storm sewers user guide

Hydraflow Storm Sewers Extension

for AutoCAD® Civil 3D® 2009

User’s Guide

January 2008

ii

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Table of Contents

1 INTRODUCTION ...................................... 1

Help and Documentation ..................................................................... 1

System Requirements ......................................................................... 1

Starting Hydraflow Storm Sewers Extension .................................... 1

2 OVERVIEW ............................................... 2

Upgrading From Previous Versions ................................................... 2

General Modeling Guidelines.............................................................. 4

The Basics of Running Hydraflow Storm Sewers Extension .......... 4

Quick Start Tutorial .............................................................................. 8

3 RUNNING HYDRAFLOW STORM SEWERS EXTENSION.............................. 22

Entering Data ...................................................................................... 22

Hydraflow Storm Sewers Extension's Main Menu .......................... 22

The Basics .......................................................................................... 24

Setting up IDF Curves ........................................................................ 25

Design Codes ..................................................................................... 33

Adding Lines ...................................................................................... 41

Line and Inlet Data ............................................................................. 45

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Editing Lines ....................................................................................... 66

Inserting and Deleting Lines ............................................................. 76

Moving Lines ...................................................................................... 78

Estimating Cost .................................................................................. 80

Computing the System ...................................................................... 82

Computed Results ............................................................................. 96

Printing Reports ............................................................................... 115

Plotting Graphs ................................................................................ 117

Import & Export DXF / XML Files .................................................... 124

Saving and Retrieving Files ............................................................ 136

4. COMPUTATIONAL METHODS .......... 139

Standard Step Method ..................................................................... 139

The Rational Method ........................................................................ 147

Inlets .................................................................................................. 151

Design Options ................................................................................. 159

Enhanced Modeling System (EMS)TM ............................................. 161

APPENDIX A ........................................... 163

Runoff Coefficients (C) .................................................................... 163

Manning’s n-Values ......................................................................... 164

INDEX ...................................................... 165

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1 Introduction Hydraflow Storm Sewers Extension for AutoCAD® Civil 3D® 2009 is an easy-to-use, full-featured application for urban hydrosystems engineering. It was designed primarily for hydrologic and hydraulic analysis of simple and complex storm sewer networks. It can be used as a basic tool for determining the hydraulic grade line in an existing system to planning or designing new systems.

Help and Documentation Rely on the Hydraflow Storm Sewers Extension for AutoCAD Civil 3D 2009 User’s Guide and the online help to answer questions about using Hydraflow Storm Sewers Extension. Both resources are accessible from the Help menu. Click Help menu > Contents to open the online help or click Help menu > User’s Guide (PDF) to open the Hydraflow Storm Sewers Extension for AutoCAD Civil 3D 2009 User’s Guide. You can also open the online help from the application. Press the [F1] key or click the Help button in any dialog box.

System Requirements Hydraflow Storm Sewers Extension is a 32-bit program and will run on most off-the-shelf PCs running Microsoft Windows 2000, XP, or Vista operating. It requires about 20 MB of hard drive space.

Starting Hydraflow Storm Sewers Extension 1. Click [Start] on the Task bar. 2. Select Programs > Autodesk > Hydraflow Storm Sewers Extension. or Double-click the Hydraflow Storm Sewers Extension for AutoCAD Civil 3D icon on your desktop.

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2 Overview

Upgrading From Previous Versions Migrating from previous versions is easy. Hydraflow Storm Sewers Extension for AutoCAD Civil 3D 2009 will read your old project files with a .stm extension as far back as version 7.0. However, once saved in Hydraflow Storm Sewers Extension format, the files cannot be reloaded in earlier versions. Your existing files are not backward compatible. To open your previous IDF curves, simply open an old version *.IDF file. To do this, click the [IDF] button from the upper toolbar. Then [Open ] the IDF file. Hydraflow cannot open version 7 IDF files. ______________________________________________________________ Note When opening files earlier than version 2003, it may be necessary to switch over to the Pipes or Inlets tab prior to opening. ______________________________________________________________ Many new features have been added to this new version. Below are the highlights and differences from version 2005. General The overall user interface is quite similar to its predecessor. The main difference is that Hydraflow Storm Sewers Extension expands features already in place, adds new design and calculation options and reporting capabilities without added complexity. Here are the highlights. User Interface

User-defined precision for line lengths and angles. Text scaling options for Plan views and Profiles. Quicker plan layouts. Crop background images. Move outfalls without moving upstream lines.

Data Entry

Dual lines. Up to 4 barrels can be specified for each line.

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User-defined Northing and Easting coordinates for each line. User-defined junction shape, length, width or diameter. Curb inlets can be specified as horizontal or inclined (45-deg) throat. Built-in Tc calculators include TR55 and FAA methods. New Code options include default n-values, maximum slope, defaults

for structure shapes and sizes and other HGL options. Computing

Full design options include “Follow existing grade” to avoid drop-structures.

Quickly reset your project’s pipe sizes and/or invert elevations with one click. Optionally hold the outfall invert(s).

Starting HGL options include (dc + D)/2. The Interactive feature has been enhanced:

o Graphically control Known Qs. Good for determining overflows at structures.

o Elements under control are highlighted for ease of use. o Inverts can be locked / unlocked at the Interactive screen. o Options allow you to carry modifications up or downstream.

Profiles Smart labels automatically adjust themselves to avoid overlapping. User-defined text scales from small, medium to large. User-defined text scale factors for improved DXF export.

Hydraflow Storm Sewers Extension for AutoCAD® Civil 3D® 2009

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Hydraflow Storm Sewers Extension will automatically adjust label locations to avoid overlapping. Reporting

Print preview! View reports on-screen before sending them to the printer. New reports include:

o Structures report. This is a tabulated report by Structure rather than by Line.

o Tc Tabulation provides complete detail on inlet times.

General Modeling Guidelines When using Hydraflow Storm Sewers Extension you will be able to model and/or design storm sewer networks in the same fashion as traditional methods. In brief, Hydraflow Storm Sewers Extension can design and model a network of up to 250 storm sewer lines at once. The network is basically made up of "Lines". A line is a length of pipe with a junction at the upstream end. Junctions can be manholes, inlets, j-boxes or other structures where losses or gains occur. There may be more than one line entering a junction but only one may exit. Remember, you have the option of specifying multi-barrels for any line. It should be noted that Hydraflow Storm Sewers Extension can model more than one system at a time, i.e., there can be any number of outfall lines.

The Basics of Running Hydraflow Storm Sewers Extension

Starting a new project is easy. You don’t have to do anything. Once Hydraflow Storm Sewers Extension is started it’s ready to accept new data. Your system is described to Hydraflow Storm Sewers Extension by specifying the required data, one line at a time, starting at the downstream end. Don't worry about having to enter in accumulated data such as drainage areas, Tc, etc. Hydraflow Storm Sewers Extension does all this for you. In fact, as you'll see later, the amount of required data for each line is surprisingly small. But at the same time, a high level of detail can be given. And because Hydraflow Storm Sewers Extension is completely menu driven, you can perform the task you

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want, when you want. There is never a rigid course of procedures to follow, regardless of the complexity of the system. Project files are like a spreadsheet or word processor in that they are saved and opened at your convenience.

Line Numbering Hydraflow Storm Sewers Extension automatically numbers the lines in the order that they are input. Therefore the first line that is input will be line number 1 and the second line input will be number 2 and so on. This does not necessarily mean that line X flows into line X minus 1. Part of the input data for each line will be the "Downstream Line Number". This indicates to Hydraflow Storm Sewers Extension which line, line X flows into.

Typical Storm Sewer System Layout Lines are always drawn in their upstream direction starting with Line 1. Hydraflow Storm Sewers Extension can accept up to 250 lines and inlets with numerous outfalls.

+-4 3

2 5

1

The downstream line number for Line 4 is 2. Its deflection angle is -55 degrees.

The deflection angle for Line 3 is +45 degrees.

The deflection angle for Line 2 is 0.

Angles to the left are negative.Angles to the right are positive.

Outfall Begin here


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The Basic Storm Sewer Line In Hydraflow Storm Sewers Extension, a Line is a length of pipe with a junction at the upstream end. The length can be any distance upstream and the junction can be one of nine types. The pipe section can be circular, elliptical or box. The pipe cross-sectional dimensions are described by Rise and Span. The user may specify invert elevations up and down as well as finish ground or Inlet/Rim elevations. New with Hydraflow Storm Sewers Extension are user-defined structure shapes, lengths, widths or diameter. In addition, each line can have unique roughness coefficients, junction loss coefficients as well as drainage areas, runoff coefficients, inlet times and inlets.

Inlets

Any line in your storm sewer system can have an inlet at its upstream end. The available inlet or junction types are those shown on the side toolbar buttons. They are: Manhole, Curb, Grate, Combination Curb & Grate, Generic, Drop Curb, Drop Grate, Open Headwall, and None (no inlet). Gutters

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can have compound cross-slopes including gutter depressions at the inlet face. Hydraflow Storm Sewers Extension follows the FHWA HEC No. 22 methodology and inlet types.

Typical Inlet Section Note that the local depression amount and the throat height are measured from a line projecting from the slope, Sx. The Sw shown is the heavy dashed line and refers to the gutter cross slope, upstream of the inlet face. Once the system data is input, Hydraflow Storm Sewers Extension offers a Menu from which you can perform various tasks including four ways to compute results. The method used depends on the type of system and the level of accuracy needed. In either case, the end results will always show the hydraulic grade line, the full flow capacity of the system, a comprehensive inlet analysis including carryover, captured and bypassed flows, total cost along with a host of other pertinent data, drawings and graphs.

Existing Systems When using Hydraflow Storm Sewers Extension you will be able to model existing systems. Existing systems are modeled by simply describing the individual line's invert elevations, length, size, etc. It will allow you to input anticipated flows for each line by using the Rational Method, by direct entry of known Q's, or a combination of both. Hydraflow Storm Sewers Extension's automatic capacity calculation will allow you to compare the actual conditions with the system's full flow capacity. From this comparison, you can quickly

Throat Height

Local Depression, a

Sx

Gutter Width

Spread

Sw


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determine the "weak links". As you will see later, Hydraflow Storm Sewers Extension has many design abilities that will allow you to correct deficiencies in an existing system.

New Systems (design) New systems are designed in a fashion similar to modeling existing systems. Instead of entering each line's invert elevations and pipe size, the user simply omits their values. When these blank values are encountered during the calculations, Hydraflow Storm Sewers Extension automatically designs them using the Design Codes specified by you. That is, minimum / maximum pipe sizes, design velocity, pipe crown alignment, and minimum depth of cover, etc. Again, you have the option of using either the Rational Method for design flows, direct entry or both. You also have the option of entering existing values for any of the lines in your system. In addition, you may enter existing invert elevations for any line and omit the pipe size, or vise-versa. In either case Hydraflow Storm Sewers Extension will provide the missing parameter based on the design codes.

Quick Start Tutorial This manual will cover the many important topics you will need to know to use Hydraflow Storm Sewers Extension. Besides a brief discussion of modeling guidelines, each and every screen and data input item is discussed in the next chapter "Running Hydraflow Storm Sewers Extension." Hydraflow Storm Sewers Extension has a state-of-the-art user interface with prompts and error recovery routines throughout. You can easily operate Hydraflow Storm Sewers Extension by simply using common sense and following the screen instructions. You can explore around in the program by selecting the various options at the Main Menu. Adding a line is easy. From the Plan tab, just click on one of the desired junction types from the side tool bar and then drag your mouse to draw. Don’t forget…click [Ok] when finished! This can be accomplished by right-clicking your mouse and selecting [Ok] or by clicking [Ok] on the bottom of the side toolbar.

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To model a system, you first should check or set the design constraints, referred to as "Design Codes". Next, add lines from the Main Menu starting at the downstream end working upstream. Then compute the system and follow the screen instructions for reporting options. If you are familiar with storm sewer hydraulics and the basic methodology used by Hydraflow Storm Sewers Extension and want to get started right away, by all means, click the Hydraflow Storm Sewers Extension icon and get to work! Important: If you plan to use the Rational Method, you must first set up your rainfall data file. See "Setting Up IDF Curves" next chapter. (The program ships with a sample set of IDF curves which you can use at first to get started.) If you want to know more about what makes Hydraflow Storm Sewers Extension the most popular storm sewer software available, follow along with this simple example. Given:


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For this example we are give two runs of storm sewer with a proposed Drop Curb Inlet at the most upstream end. Finish elevations must match existing grade and the downstream invert at the outfall must match an existing system at elevation 100.00. Our task is to compute the flows and design the Drop Curb inlet as well as the storm sewer pipes that convey the design flows including their sizes, invert elevations and slopes for a 5-year return period. We will use the default settings in the Design Codes for our design parameters. There are basically 4 steps: 1. Draw the system 2. Add line data 3. Compute 4. View results, print reports.

► Step 1. Draw your system, beginning with Line 1. The best way is to draw these at the Plan view tab. Do this by selecting an upstream junction type from the side toolbar (just click on one of the buttons corresponding to the desired upstream junction type). Then move your mouse cursor to the downstream point of the new line and drag your mouse in the upstream direction to draw the line to the correct length and angle. To connect to any downstream line, simply begin drawing at or near the connecting junction. Hydraflow Storm Sewers Extension will automatically snap the lines together. After each line draw, click the [Ok] button to accept. Repeat this process for each line while working upstream. Add Line 1 by first selecting MH from the side tool bar.

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Next, move your mouse pointer to the downstream end of the line. This can be basically anywhere on your plan screen.

Then drag your mouse in the upstream direction to the desired length and angle. In this case, 60 feet at 0 degrees deflection. Note that the Line’s current length and angle are displayed just above the drawing surface in text boxes. They allow you to directly enter lengths and angles while drawing. You can also easily modify these later.


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When you have positioned the upstream junction, right-Click your mouse and select [Ok] or click the [Ok] button on the side toolbar to accept.

Repeat this process for Line 2. Select the Drop Curb inlet type (2nd icon from the bottom). Then move your mouse pointer to the upstream end of Line 1. (You’ll hear a clicking sound when you’re near.) Then drag your mouse pointer to a length of 50 feet at -45 degrees deflection.

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Don’t worry if you cannot exactly draw to 50.00 feet. You can edit these values later. Also, you can use the zoom functions to enlarge the drawing. Click [Ok] when done. Tip: Use the zoom buttons to make more room on the drawing surface.

► Step 2. Add the line data. Click the [Data] button on the top of the side tool bar or double-click on Line 1’s junction icon (MH) to open the Line Data dialog.


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This dialog box allows you to add/edit your line and inlet data. Click [Ok] to accept the new data. Click [Exit] to return to the main menu. Using your [Tab] key to navigate the input boxes, enter the data for Line 1 as shown below: Line ID = Outfall to Line 1 Line Length = 60.00 ft Deflection Angle = 0 deg Invert Elevation Down = 100.00 ft Inlet/Rim Elevation Down = 106.60 ft Inlet/Rim Elevation Up = 107.75 ft Tab through all other inputs as they are optional.

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All other data items can be left as is. Skip entering data for the junction/inlet as this is a manhole. Click [Ok] and then click the [Next] button to advance to the next line, Line 2. and repeat for the following data. Line ID = Line 1 to Line 2 Line Length = 50.00 ft Deflection angle = -45 deg Drainage Area = 3 acres Runoff Coefficient = 0.65 Inlet Time = 15 min.


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Click on the Inlet/Junction tab to add data for this inlet.

This inlet is a Drop Curb. Enter the following data: Inlet ID = Inlet 2DC Inlet Length = 0 (This sets it up to be automatically designed) Throat Height = 4 in Cross-Slope =.05 ft/ft Then click [Ok] and [Exit].

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► Step 3. Compute.

Click the [Run] button on the top tool bar to compute the results. The Compute System screen appears. Set the options as follows: Return Period = 5 Yrs Calculation Options = “Analysis w/ Design” Starting HGL = “Crown” Use Interactive Feature = Checked on


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Click [Ok] to start. The Interactive Design screen appears:

Hydraflow Storm Sewers Extension’s interactive feature allows you to make edits to both pipes and inlets in real time. Hydraflow Storm Sewers Extension displays a profile of Line 1. Note that it has already designed the pipe size and slope at 18-inches at 0.25% to accommodate the computed 5-yr flow rate of 9.0 cfs. Hydraulic information about this line is displayed on the top table. The items in the bottom table are available for you to modify using the spin button control on the right. The spin control will increment or decrement the data item which

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has the focus, i.e. the one with the yellow background color. You can set the focus of other data items in the table by clicking on them with your mouse. Using this interactive feature is beyond the scope of this example but will be explained in greater detail in the next chapter. Click the [Up] button to proceed upstream to Line 2.

The blue line denotes the pipe; the red line indicates the HGL. The green line shows the Inlet/Rim elevations. Again, Hydraflow Storm Sewers Extension automatically designed this line for full-flow as it did for Line 1. What’s more, since we set the drop curb Inlet Length to zero, the inlet was also automatically designed. Check it out by clicking the Inlet Section button tab on the upper left of the plot window.


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Hydraflow Storm Sewers Extension designs Drop Curb inlets by first setting the Inlet Depth equal to the Throat Height and then solving for the required length of opening. In this case, the Throat Height was set to 4 inches (0.33 ft). The resulting required length is 15.72 feet. Divided by four sides gives 3.93 feet per side. The total spread width is 17.27 ft. Occasionally you will need to tweak your designs for practical reasons. For example, an inlet with even 4-foot sides may be more practical in the field than 3.93 feet. This is easily changed by the interactive controls. First, set the focus on the Curb Length data item by clicking on that column. Its background color should be light yellow. Next, click the top part of the blue-colored spin control enough times so that the Curb Length reads 16.00. Notice that these are real-time edits and you will see the inlet hydraulics change immediately. The spread width has now decreased to 17.10 feet. This completes the design & analysis phase. Now click [Finish] to return to the main menu.

► Step 4. View results on the Results tab. After computing, Hydraflow Storm Sewers Extension offers a wide array of reports and profiles. All which can be exported and/or printed. To view the reports, click on the Results tab at the main menu.

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Hydraflow Storm Sewers Extension offers six preformatted reports as well as a complete custom report with over 95 variables to choose from. Plotting Profiles. This can be done quickly by highlighting (drag your mouse over) the rows in the Results table corresponding to the beginning and ending lines you wish to plot, and clicking the [Profile] button on the top toolbar.

The Profile screen has many options for manipulating your drawing and can also export the finished drawing to a DXF file.

More information about these options can be found in the next chapter. Click [Exit] to return to main menu.

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3 Running Hydraflow Storm Sewers Extension Entering Data

Entering data in Hydraflow Storm Sewers Extension for AutoCAD Civil 3D 2009 is easy. For the most part, you will be asked to fill in data screens in either a spreadsheet or dialog box. To fill in a data item, you need to type in the text or number and then press the [Tab] key, not [Enter]. Typically, pressing [Enter] is the same as clicking an [Ok] button while pressing [Esc] is the same as clicking [Cancel]. Hydraflow Storm Sewers Extension will then move the focus to the next item. To go back to a previous item, press [Shift-Tab].

Hydraflow Storm Sewers Extension's Main Menu As described in the Overview chapter, "General Modeling Guidelines," you will be able to model and/or design storm sewer networks much in the same fashion as traditional methods. Hydraflow Storm Sewers Extension can design and model a network of up to 250 pipes and inlets at once. The network is basically made up of "Lines". A line is a length of pipe with a junction at the upstream end. Junctions can be manholes, inlets, j-boxes or other structures where losses or gains occur. There may be more than one pipe entering a junction but only one may exit. The system is described to Hydraflow Storm Sewers Extension by specifying the required data, one line at a time, starting at the downstream end. And because Hydraflow Storm Sewers Extension is completely menu driven, you can perform the task you want, when you want. You can easily maintain a working model of your system by only adding lines as necessary. There's never a need to enter all of the anticipated lines initially. Hydraflow Storm Sewers Extension automatically numbers the lines in the order that they are input. Therefore the first line that is input will be line number 1 and the second line input will be number 2, and so on. This does

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not necessarily mean that line X flows into line X-1. Part of the input data for each line will be the "downstream line number". This indicates to Hydraflow Storm Sewers Extension which line, line X flows into. But just in case you need to label your lines to match your way of doing things, Hydraflow Storm Sewers Extension allows you to assign "Line IDs" for each line and "Inlet ID's" for each inlet. Once the system data is input, Hydraflow Storm Sewers Extension offers four ways to compute results. The method used depends on the level of accuracy needed and whether you are modeling an existing system or designing a new. Before getting started, you should read and familiarize yourself with the elements of Hydraflow Storm Sewers Extension's Main Menu. It appears when you first start Hydraflow Storm Sewers Extension.

Hydraflow Storm Sewers Extension’s main menu features a state-of-the-art user interface. The Plan View shown above is typically where you will draw your lines in. Lines can also be added from any of the data editors. The Main Menu is typical of other Windows-based cad programs. It features a pull-down menu system along with a toolbars just below the pull-down menu and to the side. Both toolbars contain command buttons that are activated with a mouse click. (The remaining part of this chapter will describe how to use each of these functions in more detail.)


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The bottom panel of the Main Menu is a status bar that displays the progress bar, project file name, and the mouse N, E coordinates.

Display Style The Main Menu offers a great deal of flexibility with four styles of display; "Plan", "Pipes", "Inlets" and "Results". The display you use will most likely depend on the task at hand. For example, when adding lines to your system, you may want to use the Plan view and graphically draw your system in, although you can add lines from the Lines and Inlets tab as well. Then, when adding the line's data, you'll use the Lines and/or Inlet views. A data dialog box is available which you can use to add and/or edit any Line data in lieu of using the spreadsheet-style editors. More about that later in this chapter.

The Basics There are just a few steps from setting up your storm sewer model to computing results and printing out professional looking reports and drawings. Below is a brief description followed by more detailed discussion.

► Step 1. Check the Design Codes. Each time Hydraflow Storm Sewers Extension is started it loads values (Design Codes, settings and cost data) from the Storm2008.ini file. As you exit the program, these values are automatically re-saved and reloaded on start-up. Be sure that the design constraints and inlet default values are set the way you like.

► Step 2. Make sure you have the correct IDF curves loaded. Some sample IDF files came pre-loaded with Hydraflow Storm Sewers Extension and to get started, you can use those. Hydraflow Storm Sewers Extension automatically loads the most recently used curve each time it is started. See "Setting Up IDF Curves" later in this chapter.

► Step 3. Draw the lines. Actually, this can be done from any display style but the Plan view is popular. Lines are added by clicking the desired inlet type (the upstream end of the line) from the side toolbar, dragging your mouse to draw to the desired length and angle, and then clicking the [Ok] button at the bottom of the side toolbar. Repeat for each line. Hydraflow Storm Sewers Extension will assign default


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data for each line as you enter them. Remember, you must click the [Ok] button for each line!

► Step 4. Add remaining line data. At this step, switch over to the "Pipes" Tab and fill in the blanks as needed. For example, the flow data and physical data such as invert elevations, pipe sizes, etc.

► Step 5. Add remaining inlet data. Optional. Since most of the inlets will be assigned default values (by you) you may not always need to check this step. Switch over to the "Inlet" Tab and fill in the appropriate data there. Any inlets on grade must have a longitudinal gutter slope specified. Tip: Steps 4 & 5 can be accomplished by using the Data Dialog. To use this, click the [Data] button on the top of the side tool bar.

► Step 6. Compute. Do this by clicking the [Run] button on the upper toolbar. View the results by switching over to the "Results" Tab. From here you can print out reports, view drawings, etc. That's it... the basics that is. The rest of this chapter will go in to greater detail. As mentioned above, eventually you're going to need to set up the IDF curves so they match your locale.

Setting up IDF Curves Hydraflow Storm Sewers Extension can develop any number of IDF curves, that is, any number of geographic locations, with up to eight return periods. Once setup, the user doesn’t need to be concerned with them as Hydraflow Storm Sewers Extension, behind the scenes, manages them. They are always loaded upon startup and remembered upon exit. During calculations, Hydraflow Storm Sewers Extension automatically computes the rainfall intensity from the currently loaded IDF curves for use in the Rational Method. But first, you must provide data so that these curves match those that you are presently using. This program ships with sample IDF


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curve files called sampleFHA.IDF and FLZone1.IDF. Feel free to use these while getting to know the program. The rainfall data file, regardless of the type of data used initially, is set up from the Main Menu. Once the IDF data has been entered, Hydraflow Storm Sewers Extension stores the IDF curves under a user-definable file name. This file is loaded each time Hydraflow Storm Sewers Extension is started. During design Hydraflow Storm Sewers Extension uses it along with the computed Tc to compute the intensity. Hydraflow Storm Sewers Extension can store an unlimited number of different rainfall files for different jobs or locations. These IDF curves can be loaded for use at any time. You have a choice of entering points from your existing IDF curves or creating them from map data.

IDF curves are automatically loaded at startup. Note the Min. Tc shown here is 5 minutes. Set in the Design Codes.

Using Existing Data To setup your curves to match existing idf data, click the [IDF] button on the top tool bar. The IDF graph will appear showing the current IDF curve. Next click the index tab "IDF Table". The following screen should appear:


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Note Experience shows that this is the better method for Western states that have been included in the latest NOAA Atlas 14. Use intensity values provided by the atlas. ______________________________________________________________

The required data, consists of the intensity values, in in/hr, for the 5, 15, 30 and 60 minute durations corresponding to the 1, 2, 3, 5, 10, 25, 50 and 100-year storms. Any return period data can be left blank. For example, if you do not use or have 1-year data, leave the values blank. To enter your own data, click the [Clear] button or just edit the table with new data. 2-Yr / 5 MIN ... 100-Yr / 60 MIN Enter the corresponding intensity amounts in inches / hour or centimeters / hour from your Intensity - Duration - Frequency curves. You must enter all of the data for each return period used. When finished, click the [Ok] button. Hydraflow Storm Sewers Extension will then calculate the corresponding rainfall intensity equation coefficients. See "Viewing IDF Curves".


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Creating From Map Data

Hydraflow Storm Sewers Extension has the ability to generate new IDF curves from NWS precipitation data. The computational procedure is that as described in FHA Circular No. 12, "Drainage of Highway Pavements." Technically, when using Hydro-35 data or existing curves, Hydraflow Storm Sewers Extension manipulates your input data to generate coefficients B, D & E, for use in an intensity vs. Tc equation.

( )DTc EBI

+=

Where: I = rainfall intensity in in/hr (cm/hr). Tc = time duration. B, D & E = coefficients. The required data can be precipitation values from NWS Hydro-35 (Eastern United States) or NOAA Atlas (Western United States) Hydro-35 and the NOAA Atlases may be available at National Technical Information Service (NTIS) 1-800-553-6847. Ask for publication number PB272112. (Hydro-35) You must be working in U.S. Customary units in order to generate IDF Curves from map data. Once you have created your curves, simply switch to SI units from the Main Menu. Hydraflow Storm Sewers Extension will do the conversion. To generate IDF curves from map data, click "IDF Curves" from the Main Menu (Pull-down) and select "Create New from Map Data". Then select "Eastern States" or "Western States".

If you are in the Eastern States If located in the Eastern and Central United States, the precipitation data from NWS Hydro-35 will be needed. The values are in total inches, not inches per hour (in/hr) and consist of the 5, 15 and 60 minute durations corresponding to the 2 and 100-year frequencies.


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To get your local rainfall data go to the National Weather Service (NWS) website. 2-Yr / 5 MIN ... 100-Yr / 60 MIN Enter the corresponding precipitation amounts in total inches. When finished, click the [Ok] button. Hydraflow Storm Sewers Extension will then calculate the corresponding rainfall intensity equation coefficients.

If you are in the Western States If located in the Western United States, the precipitation data from your state's NOAA Atlas will be needed. The values are in total inches, not inches per hour (in/hr) and consist of the 6 and 24 hour durations corresponding to the 2 and 100-year frequencies. The average elevation in feet will also be needed.

If located in the Western United States, the precipitation data from your state's NOAA Atlas will be needed. 2-Yr / 6 Hr ... 100-Yr / 24 Hr Enter the corresponding precipitation amounts in total inches.


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AVERAGE ELEVATION Enter the average ground elevation for this area. For example, the average ground elevation for Colorado Springs, Colo. could be 6000. When finished, click the [Ok] button. Hydraflow Storm Sewers Extension will then calculate the corresponding rainfall intensity equation coefficients.

Third Degree Polynomial Hydraflow Storm Sewers Extension has the option of creating IDF curves using a third degree polynomial equation as follows:

DXCXBXAI 32 +++= Where: I = rainfall intensity in in/hr (cm/hr). X = Ln(time duration in minutes). A, B, C, D = coefficients. To create polynomial-based curves, select "View/Load Curves" from the IDF curves pull-down menu or click the [IDF] button on the upper toolbar. A graph will appear showing the current IDF curve. Next click the index tab "Coefficients". Then click the [Poly] button to make sure the table is in the Polynomial mode. The following screen appears:

Click the [Clear] button to wipe out any existing data. Then just enter in the appropriate coefficients. When done, click [Ok]. Click the "Graph" tab to view the curves.


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Viewing I-D-F Curves Regardless of the method used to create your new curves, Hydraflow Storm Sewers Extension will always generate equation coefficients and a graphical display of the curves. To view this data, select "View / Load Curves" from the "IDF Curves" menu from at the Main Menu or click the [IDF] button on the upper toolbar.

These curves are Polynomial-based. This screen allows you to do several things. You can edit the equation coefficients; you can save the current IDF file; you can open a previously saved IDF file; and you can print a hard copy of the plot or get a numerical report of the IDF data. Editing Coefficients: Click the "Coefficients" tab. To change any of the coefficients, click the table cell and retype the new number. Click [Ok] when finished. To see the effect of the change on the plot, click the "IDF Graph" tab. Save File: Once the IDF curve has been generated, you should save the file. Hydraflow Storm Sewers Extension allows you to save as many different IDF curves as your disk space allows. To save, click the [Save] button. Enter a name for the file in the Filename text box. If necessary, change the drive and directory, to the location where you want to save the document. It is recommended that you save this file in the directory where Hydraflow Storm Sewers Extension was installed because Hydraflow Storm Sewers Extension


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will load this file when first started. It will look in its default directory. Also note that all IDF file names will be assigned an ".IDF" extension. Printing the curves: To print a hard copy of this plot, click the [Print] button.

A separate IDF report can be printed in graphical and/or in numerical formats Check the appropriate boxes and then click [Print]. Check the "Numerical Report" box to get a printed report of the numeric data. Open an existing curve: Click the [Open] button. The Open dialog box appears. Next, click the name of the file you wish to load. Its name should then appear in the File Name text box. Then click [Ok]. The new plot will be shown along with its corresponding numeric data. When you are finished viewing, click [Exit] to return to the Main Menu. Hydraflow Storm Sewers Extension will use the currently loaded IDF curve in all subsequent calculations. The name of the current IDF curve will appear on appropriate printed reports. When you exit Hydraflow Storm Sewers Extension, it remembers this file and reloads it the next time it is started.


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Design Codes Hydraflow Storm Sewers Extension allows you to specify certain design constraints and initial conditions before calculating results as well as setting default values for various inputs. The values as shown are preset but you can edit them at any time. To change the Design Codes, select "Design Codes" from the Edit menu or click the [Codes] button.

Hydraflow Storm Sewers Extension offers many design constraint options. The defaults button will reset the values to factory settings. Hydraflow Storm Sewers Extension will calculate and design using the current settings. When finished editing, click the [Ok] button and Hydraflow Storm Sewers Extension will return to the Main Menu. Like the IDF curves, Codes are automatically saved upon exiting Hydraflow Storm Sewers Extension and are re-loaded upon its start. Code settings are also embedded within each project file. The data for the design codes are divided into 3 categories. Each is described below. To change a data item, click the white text box and retype, or select from the list box, the new entry.


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Pipes Minimum Pipe Size

This is the smallest pipe size that Hydraflow Storm Sewers Extension will use when designing pipe sizes. Select from the list box by clicking the list box arrow.

Maximum Pipe Size This is the largest pipe size that Hydraflow Storm Sewers Extension will use when designing pipe sizes.

Design Velocity This is the design velocity in ft/sec (m/sec). When zero's have been specified for both invert and pipe rise, Hydraflow Storm Sewers Extension will select a pipe size based on this velocity. When a specific pipe size is not available, Hydraflow Storm Sewers Extension will select the next smaller size in order to maintain the Design Velocity at a minimum. For example, if the theoretical size is 19.5 inches, Hydraflow Storm Sewers Extension will round down and use an 18-inch pipe. When Hydraflow Storm Sewers Extension has been asked to set the pipe slope, it will use this velocity along with Manning's equation to compute it.

Minimum Slope Select the minimum slope in percent. Hydraflow Storm Sewers Extension will use this for design only and will not set any invert slopes less than this value. If the theoretical slope is less than the "Minimum Slope", Hydraflow Storm Sewers Extension will reset the designed slope to this value.

Maximum Slope Select the maximum slope in percent. Hydraflow Storm Sewers Extension will use this for design only and will not set any invert slopes greater than this value.


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Minimum Cover Enter the minimum cover in feet (meters). This value should be from the natural ground to the crown of the pipe. The pipe thickness is neglected. Remember, the minimum cover constraint is used only when "Full Design" has been specified as the calculation option. Otherwise it is ignored during any design procedure. Check the Zero at outfalls box ON to keep Hydraflow Storm Sewers Extension from setting the outfall ends too deep.

Default n-value Use this to automatically set the pipe roughness coefficient when adding new lines.

Size Options Hydraflow Storm Sewers Extension allows you to control which pipes are available for design. This is useful in areas where certain pipe sizes, usually 21-inch (530 mm), 27-inch (680 mm), and 33-inch (840 mm) are not commercially available. To select one of the options, click on the check box(s) corresponding to the option you wish to use.

Design Alignment During design, Hydraflow Storm Sewers Extension will match either the crowns of the pipes or their inverts. Matching crowns prevent lines from flowing into another against a head.

Match Crowns Will match crowns of pipes regardless of their size.

Match Inverts

Will match inverts.

Match crowns

Flow


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Matchline Drop This alignment option will provide a drop in invert elevation across junctions of equal pipe sizes. For example, if a 24-inch line enters and exits a junction, Hydraflow Storm Sewers Extension will automatically lower the outgoing line by the amount specified.

Allow Smaller Downstream Pipes In some cases during design, the theoretical pipe size required may be smaller than the one connecting upstream. It is not typically a good design practice for pipes to decrease in the downstream direction but if you insist, turn this option ON.

Inlets Defaults

When adding new lines to your system, Hydraflow Storm Sewers Extension allows you to preset values for the inlets and gutters to eliminate redundant data entry.

Elev. drop

Flow

Match inverts

Flow


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These items are explained in detail in the "Adding Lines" section. In essence, each time a line is added, it utilizes this data set. For example, based on the above settings, when adding a line with a curb inlet, its throat height will be 6 inches, Sx and Sw will be .02 and .05 respectively. The gutter width will be 2 feet. The gutter section at the inlet will contain a depression of 0 inches, and the gutter n-value will be 0.013. You can certainly edit the line data later. This just automatically enters the data for you ahead of time. Note that the Curb Opening affects all curb inlets and is a global setting. This setting does not apply to combination or drop curb inlet types.

Grate Design Depth When Hydraflow Storm Sewers Extension designs grate inlets in sags, it sizes the grate using the orifice equation.

)(267.0 nDepthGrateDesiggQGrateArea =

If it knows the depth and Q, it can solve for the grate size. See also, "Computational Methods."

Composite Runoff Coefficients Hydraflow Storm Sewers Extension has the option of pre-setting up to 3 runoff coefficients for use when adding line data and using composite areas. This is most useful in situations where you will always use these fixed C values. Their values will be based on the corresponding land uses. See "Adding


38

Lines" and using composite C's. You can enter your own C value for each line rather than use these.

Calculations Minimum Starting Depth

This determines how the starting water surface elevation at the downstream end of any line is chosen, except outfalls. The choices are: Normal, Crown, (dc + D)/2 and Critical depth. If the starting HGL at any line, other than an outfall line, is below the Minimum Starting Depth, Hydraflow Storm Sewers Extension will automatically set the starting HGL to this specified depth. Remember, this refers to all lines upstream, not the beginning HGL.

Correct EGL Discrepancies

This option will maintain the energy grade line at junctions in order to prevent a rise in energy in the downstream direction. This can occur when additional flows are added to the junction causing a rise in the downstream EGL. This option will hold the EGL for the next upstream line and will adjust its starting HGL (EGL – Velocity head).


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The figure on the left is an example of an increase in the EGL in the downstream direction (flow runs right to left) and the option to correct the EGL discrepancy was turned off. The example on the right shows the result when turned on. Notice the double jump in the HGL. This is a tell-tale sign that the starting HGL for the upstream line was adjusted.

Check for Inlet Control A pipe flows under inlet control when it is more difficult for flow to get IN the pipe than it is to get THROUGH the pipe. This option will check each HGL calculation for inlet control. Choose either HDS-5 method or standard orifice equation.

Accumulate Known Q's You have the option of entering a known flow into any line of your system. This feature accumulates these known Qs as Hydraflow Storm Sewers Extension works downstream if checked. Unchecked, known Q's are not added.

Use inlet captured flows in system Typically, inlet flow quantity calculations are done separately from system flows. In other words, most designers assume that all of the flows computed by the Rational Method will enter the pipes. Checked, this option will limit the system flows to those captured by the inlets. This option should typically be in the OFF position. Warning! If the junction is not an inlet, then it cannot capture inlet flows, resulting in a zero Q. If a line has a drainage area, C and inlet time, its junction type must be an inlet when this option has been checked ON. Also


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note that if the total Q’s shown on your reports don’t match the corresponding Q = Cia, this option has been checked ON.

Suppress Pipe Travel Time Turn this feature on if you want Hydraflow Storm Sewers Extension to ignore travel times in pipes when computing Tc for the system.

Minimum Tc Used to Calculate Intensity To prevent Hydraflow Storm Sewers Extension from using intensities based on Tc’s below a certain minimum, enter that minimum here.

Junction Loss Coefficients Hydraflow Storm Sewers Extension will automatically compute and assign junction loss coefficients based on the junction configuration when "Automatic" is ON. It will select these coefficients based on the following data adapted from FHWA HEC No. 22. See also, "Computational Methods." Remember, the selected coefficients will be based on the angle of the lines entering the junction at its upstream end. ______________________________________________________________ Note When using Automatic option, you will not have the ability to edit the loss coefficients when adding or editing line data. ______________________________________________________________ For bends less than 90 degrees, Hydraflow Storm Sewers Extension uses the following equation to compute junction loss coefficients.

⎥⎥⎦

⎤

⎢⎢⎣

⎡⎟⎠⎞⎜

⎝⎛ −−=

2

90901 AngleDeflectionK

If the junction is an inlet, K is multiplied by 1.5. In no case will K be less than 0.15 for Manholes or 0.50 for Inlets. For bends greater than or equal to 90: Inlets K = 1.5 Manholes K = 1.00


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For Lines at ends of a branch, K = 1.00 When Manual Entry is on you will have the option to enter user-definable coefficients.

Adding Lines Adding lines is simple in Hydraflow Storm Sewers Extension. You can add lines any time you wish and at any display tab; Plan, Lines or Inlets (but not Results) as well as the Data Dialog. It is easiest to add your lines at the Plan tab but you will eventually develop a preference. Remember, you build your system by adding lines from the downstream end working upstream. Any number of lines can enter a junction but only one may exit. The first line you enter is Line 1. The next is Line 2 and so on. Up to 250 lines can be added per project file. Each line is automatically numbered in sequence beginning with line number 1. The rest of this section will explain how to add lines from each of the various display types.

Adding From the Plan Tab

Hydraflow Storm Sewers Extension allows you to graphically draw the line by dragging your mouse in the upstream direction. Remember to click [Ok] after each line! To add a line from the Plan tab, simply click on the desired junction type from the side toolbar. Then, using your mouse, move the cross-hair close to the upstream end of the line you want this line to connect to (or at the outfall


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location). Then drag the cross-hair to the desired length and angle and release the mouse button to accept. Repeat or make adjustments as necessary. Always draw in the upstream direction. Note the line's length, angle and downstream line number are shown in the Plan tab's status bar. Important: When you have the line drawn in as desired, either click the [Ok] button on the side toolbar, right-click your mouse and select Ok, or press [Enter] to register this line. To cancel this line draw, click the [Cancel] button or press [Esc]. If you already clicked the [Ok] button but want to cancel, select "Undo" from the "Edit" pull-down menu. To continue adding lines, right-click your mouse and choose “Add Another Line”. Hydraflow Storm Sewers Extension will automatically snap to the last line drawn and will use the same junction type. That can be changed later if desired. Once a line is added, a certain amount of line data, as specified in the Design Codes default settings is automatically entered for you.

Locking In Note that you can manually enter the deflection angle and length. Clicking the [Lock] button will hold the existing values, preventing them from being changed by any further mouse movement. Click this button again to unlock. You can lock and unlock any time, before, during, and after the process.

Using the Zoom Buttons Use the three Zoom buttons on the right side of the Plan tab's status bar to zoom in, zoom out, or reset the drawing scale. When resetting, Hydraflow Storm Sewers Extension automatically selects a scale to fit the entire system on screen.

Changing the Downstream Line You can also switch the downstream line or manually select one using the "Dnstrm Line =" text box on the Plan tab's status bar. Type in the desired line number and then click the [Checkmark] button to accept. See also, "Renumbering Lines" later in this chapter.


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Adding From the Pipes Tab One the greatest advantages to the spreadsheet display is the ability to view and/or edit all of the system's data in a single screen. Adding lines from the Pipes tab is done by first selecting the downstream line by highlighting it using the line selector to the left of the line. Then click on the desired junction type on the side toolbar. (Note that it is not necessary to select a downstream line. In that case, Hydraflow Storm Sewers Extension will assign the last line added as the downstream connecting point.) At this point, Hydraflow Storm Sewers Extension automatically adds data for the line as specified in the Design Codes, along with a line length of 50 ft or 16 m. The cursor will go to the first input column and you are free to enter the remaining data. Remember to type in the data and then [Tab] to the next column. (Note that while you are adding a line, you are free to move about the spreadsheet to edit any other existing lines. Use your cursor navigation keys to move about.)

Adding lines from the Pipes tab is done by first selecting the downstream line by highlighting it using the line selector to the left of the line. Then click on the desired junction type on the side toolbar. When finished adding data, click the [Ok] button on the side toolbar to register this line...This is very important! To cancel this line draw, click the [Cancel] button. If you already clicked the [Ok] button but want to cancel, select "Undo" from the "Edit" pull-down menu.


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Each data item is discussed separately later in this section.

Adding From the Inlets Tab The procedures for adding lines from the Inlets tab are identical to the Pipes tab.

Adding From the Data Dialog Depending on your personal preferences, you may feel more comfortable using a traditional dialog box to enter and/or edit data. In this case, Hydraflow Storm Sewers Extension provides such a feature.

To access click on the Data button located on the top of the side tool bar.

To add a new line, click the [Add] button. Hydraflow Storm Sewers Extension will assign the last line added as the downstream line.) At this point, Hydraflow Storm Sewers Extension automatically adds data for the line as specified in the Design Codes, along with a line length of 50 ft or 16 m. Navigate this screen using your [Tab] key. Click on the Inlet/Junction tab to add inlet data. Click [Ok] when finished to accept. Then [Exit] to return to the


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Main Menu. See, “Editing Lines” later in this chapter for more information about this screen.

Line and Inlet Data Regardless which display type you're using, entering data is basically the same. Simply type the appropriate number or text (or select from a drop-down list box) and then press the [Tab] key. Hydraflow Storm Sewers Extension will then check the data for validity and move to the next data item. If you need to edit a previously entered item, press [Shift][Tab] to move the input cursor backwards. You can also click the desired data item (inside the white box) with the mouse. You are free to move about the data items as you choose but it is recommended that you enter the data in the order as shown. Hydraflow Storm Sewers Extension supports up to 250 lines per project file. Each data item is explained in detail as follows.

Line Data This section will cover those items for line data only. See also, "Inlet Data".


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Line ID Enter any name or label that you wish to help identify this line. For example, MHx - MHy. Do not use commas or quotation marks! This interferes with Hydraflow Storm Sewers Extension's file format. Downstream Line No. If you have drawn your system in from the Plan tab, this data item is already set. If not, enter the line number which this line flows into. The downstream line must have been previously input. The downstream line number of Line 1 is always 0... outfall. Hydraflow Storm Sewers Extension supports multiple systems (outfalls). Any line with a zero downstream line number will become an outfall. Line Length (ft, m) If you have drawn your system in from the Plan tab, this data item is already set. Also, when adding lines from the other tabs, Hydraflow Storm Sewers


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Extension sets the length at 50 feet. It is then intended for you to edit it as needed. Enter the length of this line in feet (meters). It is the distance between junction centers. Deflection Angle (Deg) If you have drawn your system in from the Plan tab, this data item is already set. As looking upstream, enter the angle between this line and the projection of its downstream line in degrees. Angles to the right are positive and angles to the left are negative. The deflection angle for Line 1 is usually 0. See figure above. However, to change the orientation of your system, you can specify an angle for line 1 or other outfall line. Northing, Easting (ft, m) Optional. These are the plan x, y coordinates. If you have drawn your system in from the Plan tab, these data items are already set. However, this feature allows you to override and set manually. Junction Type... Any line can have a manhole or inlet at its upstream end and can be in a Sag or On Grade. Select the appropriate junction type from the list box. Note that this item can also be entered at the Inlets tab as "Inlet Type". See also, “Inlet Data” later in this chapter. Known Q (cfs, cms) Enter any known or additional flow for this line. This value is added to any other incoming flows and is also carried downstream to be added to other downstream lines when "Accumulate Known Qs" is checked in the Design Codes. Note that when "Use inlet captured flows" has been checked on in the Design Codes, any Known Q's will be ignored on manholes or non-inlet type junctions. Drainage Area (ac, ha) Enter the drainage area that contributes to this line only. Hydraflow Storm Sewers Extension will accumulate the areas during the calculations.


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Runoff Coefficient (C) Enter the runoff coefficient corresponding to this drainage area. See Appendix and Help. Composite Coefficients: Hydraflow Storm Sewers Extension will compute a weighted or composite coefficient by clicking the [%] button on the side toolbar. Hydraflow Storm Sewers Extension will compute a weighted C using the three C values set in the Design Codes. Tc Options Hydraflow Storm Sewers Extension provides the option of using a known Tc or calculating it using either the FAA or TR55 methods. Choose by clicking the corresponding option button or from the drop-down list on the Pipes tab. Inlet time is the time it takes for runoff to travel from the most remote upstream point in the drainage area to the inlet in question. 1. Known Tc. This is the default method. Simply enter the Tc in minutes. 2. FAA method. Collected data from airfield drainage by the Army Corps of Engineers was used to develop this method and is now widely used in urban drainage design. 3. TR-55 method. This option allows you to compute Tc by using the 3-component Tc as used by TR-55. Hydraflow Storm Sewers Extension has a built-in TR-55 worksheet that computes Tc. Inlet Time (min) Enter the inlet time (overland flow time) for this catchment. It is usually 10 to 20 minutes. This is not the computed Tc for the system but the Tc for this inlet only. Hydraflow Storm Sewers Extension will compute the overall Tc during the calculations. If FAA or TR55 was chosen for the Tc Method, click the corresponding [FAA] or [TR55] button to open the built-in Tc calculator. If using the Pipes tab, click the special function button [%] to open the Tc calculator. Your cursor must be


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on the Inlet Time column to activate. The computed values will be automatically entered as the Inlet Time. ______________________________________________________________ Note You can model a system with rational method flow information and without inlets if desired. Simply draw your system in using manholes at junctions while specifying drainage areas, C’s and inlet times. Just don’t expect to see any inlet analysis on the reports. ______________________________________________________________

► TR55 Tc Calculation Hydraflow Storm Sewers Extension has a built-in TR-55 worksheet that computes Tc. This method computes Tc by adding the travel times of sheet flow, shallow concentrated flow and open channel flow from each of the components A, B and C, as described in Technical Release 55 (TR-55) Urban Hydrology for Small Watersheds. The individual data items are self explanatory however, a brief description of the flow types will be described below. For more information, see TR-55.

TR55 is one of three Tc options available in Hydraflow Storm Sewers Extension and has up to three components for each flow type Sheet Flow Sheet flow is flow over plane surfaces usually in the upper reaches of the drainage area. A typical n-value used is .011 for smooth surfaces such as


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concrete, asphalt or bare soil. Dense grasses yield .24, Bermuda grass is .41 while woods range from .40 to .80 depending on the underbrush. ______________________________________________________________ Note This method for computing sheet flow is limited to a flow length of not more than 300 feet. After 300 feet, sheet flow turns to shallow concentrated flow. ______________________________________________________________ Shallow Concentrated Flow Hydraflow Storm Sewers Extension automatically computes the average velocity based on the watercourse slope and surface type - Paved or unpaved. This segment is best described as the surface between sheet flow and open channel flow. Open Channel Flow For these data items, it is assumed the channel is bank-full. Hydraflow Storm Sewers Extension automatically computes the average velocity. Hydraflow Storm Sewers Extension allows you to specify up to 3 components for each flow type, areas A, B & C. In addition, these values are saved with the project .stm file. Once you have completed the data items, click the [Compute] button. Hydraflow Storm Sewers Extension will compute Tc and travel times for each segment. To print a hard copy worksheet report, click the [Print] button. Note that this report can also be printed with the Tc Tabulation report from the Main Menu so it is not necessary to print it here. When finished, click the [Exit] button.

► FAA Tc Calculation Collected data from airfield drainage by the Army Corps of Engineers was used to develop this method and is now widely used in urban drainage design.


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Flow Length Enter the hydraulic flow length in feet. Watercourse Slope Enter the slope of Flow Length as a percentage. Click Compute to calculate Tc. Then click [Exit]. Invert Elevation Down (ft, m) Enter the invert elevation of the downstream end of this line. If you want Hydraflow Storm Sewers Extension to set it for you, enter 0. Note that when adding upstream lines, Hydraflow Storm Sewers Extension will automatically place a default value equal to the upstream invert of the downstream line. Slope of Invert (opt.) (%) Enter the slope of this line in percent. This input item is optional. If entered, Hydraflow Storm Sewers Extension will compute the upstream invert and will use it as the default value for the upstream invert elevation. If you do not enter a slope, Hydraflow Storm Sewers Extension will compute it based on the invert elevations you enter. Invert Elevation Up (ft, m) Enter the elevation of the invert at the upstream end of this line. Enter 0 to have Hydraflow Storm Sewers Extension set it for you. Note that this item will automatically be set to 0 if the downstream invert is set to 0. Hydraflow Storm Sewers Extension does not design downstream inverts when the upstream invert is fixed. Line Rise (in, mm) Enter the diameter of the pipe or the height of the box or elliptical pipe in inches (mm). To have Hydraflow Storm Sewers Extension size the pipe for you, enter 0. If 0 was entered for any one of the invert elevations, Hydraflow Storm Sewers Extension will size a circular pipe based on the design velocity. Otherwise it will design it based on Manning's equation setting the slope of the energy grade line equal to the slope of the invert.


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Line Type Hydraflow Storm Sewers Extension can model circular, box and elliptical pipes. The line type that is presently specified is displayed in the list box between the Line Rise and Line Span input boxes. To change the line type, click the arrow on the right side of the list box. Then click elliptical, box or circular. Note that Hydraflow Storm Sewers Extension does not design pipe sizes for elliptical or box sections. Arch Pipes Hydraflow Storm Sewers Extension does not directly model arch pipes because of inconsistent depth-to-area relationships. If you need to model a different pipe section such as an arch, it is recommended you use an equivalent section of a box or elliptical section. Set the invert and crown to match conditions. Then compute the span that gives an equivalent cross-sectional area of the desired section. Line Span (in, mm) Enter the width of the box or elliptical section in inches. If this line is a circular pipe, press [Tab] to accept the default. No. Barrels Select from the drop-down list 1, 2, 3 or 4. Note that you do not need to adjust the Line Length for this. The Line Length is the distance between junction centerlines. Manning's n-Value Enter the roughness coefficient for this line. Hydraflow Storm Sewers Extension will assume a default value of that set in the Codes. See Appendix or help screens. To choose other n-values, click the arrow on the list box. Then click the desired value. Junction Loss Coeff. Enter the junction loss coefficient for this line. This number usually ranges from 0.15 to 1.5 and is multiplied by the velocity head of the flow exiting the junction of this line. The computed loss is then added to the HGL at the


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upstream end of this line (HGUP) to produce the (HGJ) and is typically the starting HG for any incoming lines. Hydraflow Storm Sewers Extension will automatically compute and assign junction loss coefficients, based on the junction configuration, when "Automatic" in the Design Codes is on. See "Design Codes" this chapter. See also, "Computational Methods", Chapter 4. ______________________________________________________________ Note When using the "Auto" option, you will not have the ability to edit the loss coefficients. Switch to manual afterwards for further editing. ______________________________________________________________ Inlet / Rim Elev. (ft, m) Enter the finish or natural ground elevation at the upstream end of the line. This item will be used for design when calculation option "Design" is chosen. Otherwise this entry is only cosmetic. Note that you'll need to enter the downstream Inlet/Rim elevation when entering Line 1 or other outfall line data. At other lines, the downstream Inlet/Rim elevation is shown but disabled. User-Defined Station Up / Down (Data Dialog box only) This is an optional item and is only available in the Data Dialog box. Enter any user-defined value that corresponds to this Line. These typically are stations developed from a baseline or centerline from a base map. See figure below. Hydraflow Storm Sewers Extension will optionally plot your profile drawing(s) using the stations. See, “Plotting Graphs” later in this chapter.


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For example, User-Defined Stations for the system used in the Quick-Start Tutorial would be entered as: Line 1 User Defined Sta Down = 50.00 User Defined Sta Up = 110.00 Line 2 User Defined Sta Down = 110.00 User Defined Sta Up = 145.35 The resulting profile will plot as follows:

Hydraflow Storm Sewers Extension can optionally draw profiles with user-defined stationing.

Ok [Command Button] When finished, click the [Ok] button. Hydraflow Storm Sewers Extension will then check the data for validity and go into a viewing mode. Line Data Summary You can add lines to your system at any time. Hydraflow Storm Sewers Extension assumes that you are adding them in the upstream direction. Line numbers are automatically assigned and increase in the upstream direction. Line 100 can have a downstream line number of 30. But line 30 cannot have a downstream line number of 100. In other words, when you assign a


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downstream line or inlet number, that line must already exist in the system. More than one line may enter a junction but only one may exit. Flows for each line may consist of known Q's and/or Rational method flows. If a particular line does not have any incoming overland flows, i.e., a manhole, then the Flow Data can be skipped. Just enter 0's. Hydraflow Storm Sewers Extension will carry upstream flows through the line. You may specify actual invert elevations or skip these as well. The same applies to the line size. What you leave out, Hydraflow Storm Sewers Extension designs. Some restrictions apply however. It is also important that because Hydraflow Storm Sewers Extension uses an energy based method for HGL calculations, negative line slopes are allowed. Hydraflow Storm Sewers Extension will not, however, provide design options or compute full-flow capacities for lines that are on negative slopes.

Inlet Data Any line in your storm sewer system can have an inlet at its upstream end. The available inlet types are shown in the dropdown list box at the corresponding input box and are basically those shown on the side toolbar buttons. They are: Manhole, Curb, Grate, Combination Curb & Grate, Generic, Drop Curb, Drop Grate, Open Headwall, and None (no inlet). Gutters can have compound cross-slopes including gutter depressions at the inlet face. Hydraflow Storm Sewers Extension follows the FHWA HEC No. 22 methodology and inlet types. However, since HEC-22 uses unique grates on grade, Hydraflow Storm Sewers Extension assumes the frontal flow ratio, Rf, is equal to 1.

Throat Height

Local Depression, a

Sx

Gutter Width

Spread

Sw


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Typical Inlet Section Inlet Captured, Bypass & Carryover Flows

Hydraflow Storm Sewers Extension will automatically compute bypass, captured and carryover flows. Captured flows are the flows that are intercepted by the inlet. Bypass flows are those that were not captured. Carryover flows are bypassed flows from other inlets. Carryover flows are combined with any runoff and known Qs to compute the total flow subject to capture by an inlet.

Plan View of Inlet. Carryover flows come from other inlets. Bypassed flows are directed to the BypassTtarget inlet.

Curb inlet with bypass flows


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There are many design options when specifying inlets. In general, Hydraflow Storm Sewers Extension will size inlet curb opening lengths and grate sizes for 100 percent capture when their respective data items have been set to 0. Note that certain data items will not be required depending on the inlet location -- sag or on-grade. When this happens, Hydraflow Storm Sewers Extension will display those items' background as “-----“. Simply skip (tab through) these data items. These inlet types and their required data are shown below.

Inlet Types When a manhole has been selected, other inlet data will not be required.

Curb Inlet

A typical curb opening inlet will have a rectangular opening along the face of the curb to which it is attached. They can have horizontal throat openings or inclined throat openings. (This is set in the Codes). Hydraflow Storm Sewers Extension assumes inclined throat openings to be 45-degrees.


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All curb inlets within a project must be horizontal or inclined. This setting is found in the Codes.

Grate Inlet

When using grate inlets on grade, the Gutter Width should equal the Grate Width.


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Combination

Combination inlets require the same input data as both Curb and Grate Inlets. Note that you may enter unique lengths for the grate and curb opening. When the curb opening is larger than the grate length, Hydraflow Storm Sewers Extension assumes the open curb portion to be located upstream of the grate, often called a "sweeper" inlet. Combination inlets are assumed to have horizontal throat openings.

Sweeper Inlets Per HEC-22, the capacity of combination inlets on grade is equal to the grate alone. Capacity is computed by neglecting the curb opening. The sweeper inlet has an interception capacity equal to the sum of the curb opening upstream of the grate plus the grate capacity. The grate capacity of sweeper inlets is reduced by the interception by the upstream cub opening.

Generic Inlets Use this inlet type if none of the other inlet types here work for your particular situation. It’s good if the inlet type is not important and you already know what the capacity is, or if you want Hydraflow Storm Sewers Extension to design a capacity for you. For example, if this generic type has a known capacity of 10 cfs, Hydraflow Storm Sewers Extension will bypass 2 cfs if the Q catchment plus Q carryover equals 12 cfs. ______________________________________________________________ Note Generic inlets are not intended to be used in sags, i.e., zero gutter slope, when the user-specified capacity is less than the total Q. When this happens,


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Hydraflow Storm Sewers Extension will bypass the excess to the bypass line number. ______________________________________________________________

Drop Curb Inlets These inlets are a type of curb inlet used in sags in open yard areas. They typically have four sides with rectangular openings.

Note that the length entered should be equal to the sum of the four sides and that compound cross-slopes are not allowed.


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Drop Grate Inlets Drop grate inlets are similar to the drop curb inlets except that they can be in either sag or grade locations. Their Sx, Sw values must be equal.

Open headwalls

Open headwalls do not require gutter or inlet input data. Selecting this junction type is mainly for cosmetic reasons. Headwalls capture 100% of the flow. Enter the Ground/Rim elevation as it corresponds to the top of the headwall. Do not attempt to use this junction as an outfall.

No Junction

Select the "No Inlet" when you need to connect two pipes without the use of a traditional junction. This may be useful for modeling pipes on curves. Simply make them a series of straight lines with “No Junction” as the junction type. The loss coefficient, when in the "Auto" mode, is treated the same as a manhole.

Gutters

Among other data, each inlet has a gutter cross section that consists of a gutter width and slope, and compound gutter cross slopes, Sw and Sx, and an optional local depression. Note that any time Sx and Sw have unique values, HEC-22 calculations treat gutters as if they were depressed. In fact,


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they are depressed.

Note the heavy dotted line refers to the gutter slope at the inlet face. The specified Sx and Sw's refer to the gutter upstream of the inlet. At the inlet face, Sx and the depression value are used to describe the section. Hydraflow Storm Sewers Extension automatically computes spread widths and flow depths in the gutter section. For drop curb and drop grate inlets, Sw should equal Sx. The program does not allow compound sections for these types. The following describes individual data items for inlets and gutters. Note that certain cells on the input grid will be marked out with “----“. This indicates that data is not required for that particular junction. Simply [Tab] through those cells. Inlet ID Enter any name or label that you wish to help identify this inlet. For example, Inlet 1. Do not use commas or quotation marks! This interferes with Hydraflow Storm Sewers Extension's file format. Inlet Type Any line can have a manhole or inlet at its upstream end and can be in a sag or on grade. Select the appropriate inlet type from the list box. Note that this item can also be entered at the Pipes tab as "Junction Type".

Throat Height

Local Depression, a

Sx

Gutter Width

Spread

Sw


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On Grade or Sag If this inlet is on a continuous grade, select “On Grade” from the drop-down list box. If it is in a sag or sump location, select Sag. Note that this item is not required for Manholes, Headwalls, and None. Also, Drop Curb inlets are assumed to be in a sag condition. Bypass Target Enter the number of the line/inlet in which all bypass flows are to go. Enter 0 to have the flows sent offsite. Note that unlike Downstream Line Numbers, inlet bypass flows can be sent to any inlet in your system. This is most useful for when gutters flow opposite their line flow. This target will be indicated on the Plan tab when "Gutter Lines" has been checked ON at the Main Menu Options menu.

In the system shown above, the downstream line number for Line 2 is 1 but its bypass target is Line 3. Inlet Length (Curb, Combination, and Drop Curb inlets) Enter the total length of the opening in feet or meters. Tip: By setting this value to zero, Hydraflow Storm Sewers Extension will automatically design it for you based on 100% capture. Throat Height (Curb - Horiz, Combination, and Drop Curb inlets)

This is the height of the opening in inches or mm and is measured from the projection of cross slope, Sx. Do not include any local depression amount. See figure above.

1 2

3

Bypass


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Throat Height (Curb-Inclined throat)

This is the height of the opening in inches or mm and is measured perpendicular to the throat opening angle (assumed to be 45-deg). Do not include any local depression amount.

Opening Area (Grate, Combination, and Drop Grate inlets)

Enter the clear opening area of the grate. Required only in sags. Grate Width & Length (Grate, Combination, and Drop Grate inlets) Enter the width and length of the grate. Tip: Set the Length to zero for automatic design. Hydraflow Storm Sewers Extension will size the inlet length for 100% capture. When Hydraflow Storm Sewers Extension designs for grates in sags, including combination inlets, it sizes the grate opening area based on the "Grate Design Depth" in the Design Codes. Known Capacity (Generic inlets) Enter a known or assumed capacity for this inlet in cfs, cms. Note that if the generic inlet has a known capacity of 5 cfs, for example, Hydraflow Storm Sewers Extension will bypass 2 cfs if the Q catchment plus Q carryover equals 7 cfs. Caution: Generic inlets are not meant to be used in sags. When the user-specified capacity is less than the total Q, Hydraflow Storm Sewers Extension will bypass the excess to the bypass target line.


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Tip: By setting this value to zero, Hydraflow Storm Sewers Extension will automatically design it for you based on 100% capture. Cross Slope, Sx Enter the transverse slope of the pavement section only, Sx in ft/ft or m/m. See figure above. Equals Sw when modeling Drop inlets. This item is not required for Manholes, Headwalls or None inlet types. Cross Slope, Sw Enter the transverse slope of the gutter section only, Sw in ft/ft or m/m. Equals Sx when modeling Drop inlets. This item is not required for Manholes, Headwalls, None and Drop inlet types. Local Depression Enter any local depression amount in inches (mm). This value is measured from the projection of Sx. See figure above. Gutter Width Enter the width of the gutter section in ft (m). This is the width as it corresponds to the Sw value, if specified, and should not be less than any grate widths specified for this line. If this is a Drop Grate inlet, you should select a width wide enough to contain the entire grate width. This item is not required on Manholes, Headwalls, None, and Drop Curb inlet types. Longitudinal Slope Required for inlets on grade. Enter the gutter slope, or longitudinal slope of this inlet in ft/ft (m/m). If the inlet is located in a sag, Hydraflow Storm Sewers Extension automatically sets this to 0 and disables the input box. This item is not required on Manholes, Headwalls, None, Drop Curb inlet types or inlets in sags.


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Manning's n-Value Select an n value for the gutter section. This is not required on any inlet in a sag, Manholes, Headwalls, None and Drop Curb inlet types. Structure Shape Optional. This defines the shape of the junction. Choose Circular or Rectangular from the drop-down list. Structure Diameter / Length, Width Optional. If the shape is circular, enter the diameter in ft(m), otherwise enter the length and width. The length is in the direction of the pipe length while the width is perpendicular.

Editing Lines Invariably, you will need to change or edit your line data from time to time. Hydraflow Storm Sewers Extension allows you to edit any data item at any time. The results can then be quickly recalculated. Note that once a line has been edited the results status light on the Results tab will show [COMPUTE]. This indicates that the current results may not be compatible with the current input data and reports may not be printed or the inlet plots are disabled. Re-compute to bring the results up to a current status. Editing line data is very simple. There are three ways of doing it. 1. Double click the line or data item you want to edit. This method is the fastest and most popular. 2. Click the [Edit] command button on the upper toolbar. 3. Select "Edit Line(s)." from the "Edit" pull-down menu at the Main Menu. When at the Plan tab, you must first "Select" a line to edit. Select by clicking on the line with your mouse. Its color will change to red.


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Once in the edit mode, make the desired changes and then click the [Ok] button or press the [Enter] key to accept or click the [Cancel] button or the [Esc] key to abort.

Edit Undo Hydraflow Storm Sewers Extension offers an undo command just in case you inadvertently [Ok]'d an edit, add or compute. In fact, the undo command is available after adding a line, editing a line, inserting or deleting a line, renumbering lines, and compute. To undo, select Undo __ from the Edit pull-down menu.

Plan Tab Editing Options Once you have entered at least one line into your system, Hydraflow Storm Sewers Extension draws and displays your system at the Plan tab. Here you can manipulate the layout. Typically, you will want to enlarge the drawing, move the drawing up, down, left or right, and print the drawing. To move or change the length any line, simply double-click on the line and drag your mouse to make the change. When finished, click [Ok].

It should be noted that when the display option “Show Junction Icons” is on, double-clicking the icon opens up the Data Dialog box for editing. To edit the line’s length and angle, double-click the line itself.


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Locks

While adding or editing lines Hydraflow Storm Sewers Extension offers options to directly enter deflection angles and line lengths. Additionally, these parameters can be locked to maintain their current values. Click the appropriate lock button to lock. Click again to unlock.

Nodes At the Plan tab is a nodes lock / unlock button. If in the locked position, all junctions except the one selected for edit will hold their coordinates. When unlocked, all upstream junctions will maintain their deflection angles but will be relocated according to the new position of the edited line.

Deflection Angles This text box will display the current line’s deflection angle. While in the edit mode, you can directly enter the deflection angle. If locked, the deflection angle is held while adjusting the line length.

Length This text box will display the current line’s length. While in the edit mode, you can directly enter the length. If locked, the length is held constant.

Downstream Line Number

While in the edit mode, you may directly enter or edit the current line’s downstream line number. Type the new value in the text box and click the [Apply] button to accept.

Labels

Hydraflow Storm Sewers Extension allows you to annotate your drawing with user-defined labels. They can be placed anywhere on the plan drawing and


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can be of any available font and color. Do not use quotation marks (“) in the label text.

Adding Labels

To add a new label, click the [Add Label] button. Then move the label box to the desired location on your plan and click your mouse. Next, type in the desired text. After that you can change the font (see below) or click the [Ok] button on the side tool bar to accept.

Editing Label Fonts

While editing or adding labels you can change the font by clicking the [Label Font] button. This opens the Font dialog box. Make the change and click [Ok] to return to the Main Menu. Click the [Ok] button on the side tool bar to accept.

Moving Labels Once a label has been added it can be moved by dragging its handle (the upper left corner of the label text) to a new position. It is not necessary to be in the edit mode to move a label. To move, position your mouse cursor over the upper left corner of the label text. Your mouse pointer will change to a cross-hair. Then drag to the new position.

Editing & Deleting Labels Any label can be edited by double-clicking it. To delete a label, click on the text to highlight and then click the [Delete] button on the top toolbar.

Label Display Options


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Hydraflow Storm Sewers Extension allows you to select which types of labels appear on your plan. These can be toggled on/off by clicking the [Label Display] button and selecting the desired toggle. These options are also available from the Options pull-down menu however is only enabled while in the Plan tab. The Text Scale option allows you to adjust the size of the labels (except User-defined) from small to medium to large. The Auto selection will adjust their font size based on the drawing scale. Note that the junction icons will turn off automatically when the x-scale of the drawing exceeds 2,000 feet or on line numbers >100.

Zoom Options

Hydraflow Storm Sewers Extension has four zoom options which enlarge, reduce and reset the drawing scale. Feel free to use this feature before, during and after adding or editing. Zoom In: This feature allows you to enlarge the drawing. To enlarge the drawing, click the [Zoom In] command button. The mouse cursor will change its shape to a cross-hair centered inside of a red rectangle. This rectangle represents the scale limits of the enlarged drawing. Move the rectangle with your mouse to the area you want to enlarge and then click your left mouse button. Hydraflow Storm Sewers Extension will then redraw the system to an enlarged scale. Repeat this process to enlarge further.


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Zoom Out: Clicking the [Zoom Out] button enlarges the drawing extents. Repeat as desired. Reset Scale System: When Hydraflow Storm Sewers Extension draws your system on the screen, it selects a scale such that the entire system will be displayed. To redraw the system to this default scale, click the [Reset] button. Reset Scale Background: When Hydraflow Storm Sewers Extension draws your background image on the screen, it selects a scale such that the entire image will be displayed. To redraw the image to this default scale, click the [Reset Background] button. Vertical Scroll Bar - By clicking the arrows on this bar, you can move the system drawing up or down. This can also be accomplished by dragging the scroll box up or down. Horizontal Scroll Bar - By clicking the arrows on this bar, you can move the system drawing left or right. This can also be accomplished by dragging the scroll box left or right.

Background & Foreground Colors Hydraflow Storm Sewers Extension allows you to change the background and foreground colors of its plan view. The default colors are a white background and blue foreground. These colors can be modified at any time. Here's how. Select either "Foreground - Lines", "Foreground - Inlets", "Background" or "Defaults" from the "Options / Plan View" menu at the Main Menu. To change the color, simply click the color of your choice and then click the [Ok] button. To reset the foreground and background colors to the defaults setting, select "Defaults". Note: The foreground - Inlets refers to the direction of the bypass and carryover flows of the inlets. Not the inlets themselves.


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What are those green lines on my plan? These lines indicate the direction of the bypass and carryover flows. You can toggle the bypass inlet lines on to off by clicking "Gutter lines" from the "Options/Plan View" menu.

Move System Perhaps not important without a background map, Hydraflow Storm Sewers Extension allows you to move the entire system of lines with one procedure. To do this, move your mouse cursor over the downstream end of Line 1 or any outfall. The cursor will change to a cross-hair. Then drag to the new position. Watch the X and Y coordinates on the lower status bar. For more information on moving branches of lines, inserting & deleting lines, see “Moving Lines” later in this chapter. Setting the Outfall Coordinate If you need to move your system to specific coordinates in order to match another map, you can do so by selecting any line in the system, then select “Set Outfall Coordinate…” from the Edit menu.


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This feature allows you to set the N,E location of the outfall. Moving the Outfall Only Occasionally you will need to move just the outfall point while preserving the rest of the pipe system’s node locations. This is the same procedure as moving the system except first, lock the nodes. Then move your mouse cursor over the downstream end of Line 1 or any outfall. The cursor will change to a cross-hair. Then drag to the new position. All other lines will stay in place.

Lines & Inlets Tab Editing Options The Lines and Inlet grids behave much like a traditional spreadsheet. To edit, double-click on the data item you wish to edit. Make the change and click [Ok]. While editing, you are free to move about the rows and columns to edit other data items. Use the [Tab] key to navigate through cells. Use the scroll bars to view hidden rows and/or columns. Undo, Cut, Copy, Paste, Delete and Select All When in an editing mode, clicking the right mouse button brings up an editing menu which allows the Windows traditional cut, copy, paste and delete commands. This feature is useful for typing in redundant or repeated data.


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The Lines and Inlet grids behave much like a traditional spreadsheet.

The Data Dialog

Hydraflow Storm Sewers Extension offers a traditional dialog box for which you can add and edit data. This box is opened by clicking the Data button on the top of the side tool bar or by double-clicking the junction icon. Junction icons must be visible. They can be turned on/off from the Label Display option button or from the Options pull-down menu. Navigate this screen using your [Tab] key. Click on the Inlet/Junction tab to edit inlet data. Click [Ok] when finished to accept. Then [Exit] to return to the Main Menu. Use the arrowed navigation buttons to move upstream and downstream.


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Depending on your personal preferences, you may feel more comfortable using a traditional dialog box to enter and/or edit data

Global Editing This screen has an editing feature which will apply data edits to any range of lines in your system. For example, you may wish to reset the pipe sizes for a range of lines or even raise or lower the inverts for the entire system. Here’s how it works… Move the cursor to the data item you wish to change. Type in the new data and click [Global]. The following screen appears:

Select the range of lines for this edit to be applied from the two list boxes. For example, From Line No. = 2. To Line No. = 6. Click the [All] button to apply to all lines. Then click [Ok]. Hydraflow Storm Sewers Extension will make the changes to the selected range of lines and will acknowledge when completed.


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Click [Ok] to return to the data dialog box. Invert Elevation Options When global editing invert elevations you can either specify absolute values or add a “+” or “-“ prefix to a value to be added to the existing data. For example, to lower each invert elevation by 1 foot, you could enter “-1”. To raise the inverts by 0.5 you should enter “+0.5”.

Inserting and Deleting Lines Hydraflow Storm Sewers Extension allows you insert and delete lines as well as inserting junctions into existing lines in your system at any time. When inserting or deleting, Hydraflow Storm Sewers Extension re-numbers the lines from the point of deletion or insertion to the last line by decrementing or incrementing them 1. The Line IDs along with all other line and inlet data are preserved.

Deleting Lines

To delete a line, select the line you want to delete with the mouse pointer. Then click the [Delete] button on the upper toolbar or select "Delete Line" from the Edit pull-down menu. The line will be deleted without warning. Use the Undo command to restore inadvertent deletes.

Inserting Lines & Junctions

Hydraflow Storm Sewers Extension allows you to insert lines within an existing system or junctions within existing lines.

Inserting Lines To insert a line, first select the line you want the new inserted line to flow into. In other words, the line you select will be the "Downstream" line for your new line. If no line is selected, a new line will be inserted downstream of Line 1.


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Then click the [Insert] button on the upper toolbar and select “Insert Line” or select "Line_Insert" from the Edit pull-down menu. Hydraflow Storm Sewers Extension will automatically insert a new line, 50 feet, 15.2 meters, long and using any defaults for the inlets. Whichever inlet type was last used will be used during a line insert. Next, follow the same procedure as for adding a new line. Click [Ok] when finished. Note that you cannot cancel a line insert. You must use the Edit Undo command to revert to the previous plan. To insert a new Line 1, do not select a line. Also note that you cannot insert downstream of an outfall other than Line 1. If you need to do this, just add a new line to the upstream end of the outfall line. Then edit the outfall line. The new line number will always be the selected downstream line number plus one. Hydraflow Storm Sewers Extension must keep the lines in an ascending order to correctly calculate the system flows and HGL. Tip: If the drawing scale is too large to easily select a single line, simply "Zoom" in on that portion of the plan and then select the line. The example below demonstrates Inserting a line between lines 1 and 2.

Before inserting Line 2 Select Line 1. Click [Insert] and select “A New Line”. Then click [Reset Scale] zoom button (optional). Hydraflow Storm Sewers Extension will insert a new line between Line 1 and a Line 3 (The previous Line 2).


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After inserting Line 2 Note that line 2 was incremented by one. Also note that the deflection angles were preserved.

Inserting Junctions You can insert a junction into an existing line first highlighting the line for insertion and then clicking the [Insert] button and selecting “Junction in a Line”. Hydraflow Storm Sewers Extension will automatically insert a Manhole junction in the selected line midway between the upstream and downstream ends. Move the new junction to the desired location by dragging your mouse. Click [Ok] on the side tool bar when finished to accept. Next, double-click the junction icon to make any desired data edits. Note that Hydraflow Storm Sewers Extension will set the invert in and out elevations as well as the ground elevations of the new junction by straight line interpolation between the upstream and downstream junctions. Also, each line number upstream of the new junction will be incremented by 1.

Moving Lines On occasion you may have the need to relocate an entire branch of lines in your system. In many cases you can simply change the downstream Line Number of the line you wish to move. All other connecting lines will then follow. However, this may not be possible if the new downstream line has a higher line number. Hydraflow Storm Sewers Extension allows you to move an entire branch of lines by simply dragging your mouse. Here is an example.


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Suppose you need to relocate Lines 4 through 6 from Line 3 to Line 10. First, turn off the Junction Icons by clicking on the [Label Display] button and turning off “Show Junction Icons”.

Next highlight the most downstream line of the branch you wish to move. In this case, Line 4. Only click once to highlight. You do not need to be in the Edit mode to move branches. Move your mouse pointer over the downstream end of the highlighted line, Line 4. The mouse pointer changes to a cross-hair.


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Drag your mouse to the upstream end of the new location, Line 10. You’ll hear a clicking sound when Hydraflow Storm Sewers Extension snaps to the new line. Then release the mouse button. The plan will appear as shown below.

After moving a branch of lines. Notice how the lines have been renumbered. The previous Line 10 is now 7. But all data is preserved. Turn the junction icons on again by clicking on the [Label Display] button and turning on “Show Junction Icons”.

Estimating Cost Hydraflow Storm Sewers Extension has the ability to compute the total cost of your design including pipe and cut depth quantities. During the design calculations, Hydraflow Storm Sewers Extension automatically computes the system cost. Before computing the costs, you will need to enter the cost codes. To get started, click the [Codes] button on the Main Menu. Then click [Setup] in the Cost Codes frame.

General Hydraflow Storm Sewers Extension computes the pipe quantities and cut depths based on its cost table. For example, in the table below, a 15-inch pipe


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that is buried from 6 to 8, invert to grade, will cost $40.00 / lf. During the calculations, Hydraflow Storm Sewers Extension will compute the total quantity of 15-inch pipe that falls into this cut depth category and multiply it by $40.00 to arrive at a cost. Each pipe size in each cut category is investigated during the calculations. Next, these subtotals are added to get the total system cost. An on-screen and printed cost report is available.

Hydraflow Storm Sewers Extension allows you to set up three different scenarios, each with unique cost values and cut depth increments. Each scenario can be assigned its own name or description as defined by you. It should be noted that the cost codes are optional. The program has cost codes already built-in, but they may not apply to your specific situation. Scenario Description Enter a description in the description box. This entry corresponds to the option button that is currently turned on. As you are typing the description, the name next to the corresponding option button will match. The example above shows the first scenario name as "RCP" for reinforced concrete pipe. The table columns are set up using the Initial Depth and Increment as defined by you. These values must be whole feet or meters. Initial Depth Type in the first depth increment, i.e., from 0 to Initial Depth, and press the [Tab] key.


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Increment Type the amount to increment and press the [Tab] key. The remaining columns will be set up based on this value. Table Values Next, type in the corresponding unit costs in each row and column, pressing the [Tab] key on your keyboard after each entry. Any cost amount for any pipe can be left blank if needed. The first row is set aside for junctions, manholes, inlets, etc. When finished, click [Apply]. Repeat this process for the other scenarios as needed. To switch to another scenario, simply click the corresponding scenario option button. Hydraflow Storm Sewers Extension automatically saves this cost table in its Storm2005.ini file upon exit and reloads it upon starting.

Computing the System Once you have entered your line data, set the Design and Cost Codes and loaded your IDF curve, you are ready to calculate. This is initiated by selecting one of four options from the "Compute" menu or by clicking the [Run] button at the Main Menu. Hydraflow Storm Sewers Extension will compute your system using one of four methods; Analysis and Design, Enhanced Modeling System (EMS), Full Design, and Capacity Only. Each method is described below in greater detail. Other options allow you to quickly reset the pipes sizes and/or invert elevations to zero. This is useful for doing redesign work. Hydraflow Storm Sewers Extension also allows you to interact during the calculation process. This interaction feature allows you to modify the pipe sizes, slopes, invert elevations, most inlet data, etc., during the design in real time!


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By clicking the [Run] button on the upper toolbar, Hydraflow Storm Sewers Extension displays the following screen:

Once you have entered your line data, set the Design Codes, you are ready to calculate.

Hydrology Return Period Select a return period from the list box. The Rational method flow calculations performed will be based on this return period. If you are using Known Q's or calculation option, "Capacity Only", this item is cosmetic and does not affect calculations. In these cases you may select “Known Qs only”. Tip: It’s always a good practice to check your IDF curves. In many technical support cases, users get no-flow error messages because their IDF curves have not been set up or are blank, resulting in zero Q’s.

Calculation Options Hydraflow Storm Sewers Extension has four options when computing results. Calculation options are selected by clicking the appropriate option button.


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1. Analysis and Design (New or existing systems) After computing flows, this option analyzes and designs from the downstream up and will use any and all existing data for the calculations, i.e., pipe sizes and/or invert elevations input by you. Any data that has been set to 0, for design, will be designed by Hydraflow Storm Sewers Extension. Hydraflow Storm Sewers Extension first calculates the pipe size based on the specified design velocity, i.e., Q/V = A. Next it computes the corresponding invert slope based on Manning's equation, and with the new pipe area. Based on the settings in the Design Codes, it sets the downstream crown (or invert) equal to the next downstream line's crown (or invert). If all inverts have been set to 0, then Hydraflow Storm Sewers Extension begins at the downstream end of Line 1, sets the crown elevation equal to the starting HG, and proceeds upstream. Hydraflow Storm Sewers Extension will not assign any pipe sizes outside the range as specified in the Design Codes. Use this option when downstream constraints are important, when modeling existing systems and when correcting deficiencies in a system. Just remember this methods works from the downstream up and the minimum cover constraint will be ignored. 2. Enhanced Modeling System, EMSTM Traditionally, storm sewers are designed to flow full. This is acceptable because the pipes are sized to accommodate the design flows and velocities. Thus there are no conflicting numbers, i.e., Tc's match the Q's. When analyzing existing systems, however, the actual velocity is not known until the hydraulic grade line (HGL) is computed. The computed Q's and HGL are based on assumed pipe velocities. When the real velocity is different from the assumed velocity, the computed Tc is incorrect and thus the computed Q and resulting HGL are incorrect. EMS solves this problem by directing Hydraflow Storm Sewers Extension to re-compute the hydraulic grade line based on actual flow rates and actual Tc's. To do this, Hydraflow Storm Sewers Extension must compute three system iterations so that the computed Tc's match those that were assumed with reasonable accuracy. Hydraflow Storm Sewers Extension first computes the HGL using Tc's based on the design velocity. It then computes the system a second time using Tc's based on actual velocities. These new velocities are still incorrect because they are based on the original HGL calculation, but they are more accurate


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than those used on the first trial. As one would expect, several system iterations would cause the Q's, Tc's and resulting HGL to converge to correct values. After extensive testing, it has been concluded that three iterations is the most practical balance between accuracy and the time required to produce the results. This option should be used on existing systems when the hydraulic analysis is critical and maximum accuracy is of importance. Note that EMS has all of the design features of the "Analysis & Design" option. Also note that the pipes and slopes are designed on the first iteration, not each one thereafter. 3. Full Design (New systems only) When using this option, Hydraflow Storm Sewers Extension resets all pipe sizes and invert elevations to zero and re-designs the entire system. It first sizes pipes based on the specified minimum/maximum pipe sizes and design velocity. It then computes the invert slopes using Manning's equation and the computed pipe size. Next it sets the invert elevations as high as possible but always below the minimum cover specified. At junctions, the outlet invert elevation is fixed by the lowest Inlet/Rim elevation. Note that this option requires all lines to have Inlet/Rim elevations. When selecting pipe sizes, Hydraflow Storm Sewers Extension computes the required area based on the design velocity. All pipe sizes will be within the range specified in the Design Codes. Follow Ground Surface This option will force the pipe slopes to follow the ground surface rather than the theoretical slope produced by Manning’s equation. This will reduce the possibility of drop structures as well as excavation costs. In any event, the pipe slope will not exceed the Maximum Slope set in the Codes. Use the Full Design option when upstream constraints are important and when designing news systems. Just remember this methods works from the upstream down and adheres to the minimum cover constraint. 4. Capacity Only (Existing systems) This option is most useful when you simply want to use the Q's equal to the full-flow capacity of the pipe(s). You may not know anything about the system as far as flow rates are concerned but would like to know the capacity of each


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of the lines. When this option is used, any Rational method flow data and known Q's are ignored. Instead, Hydraflow Storm Sewers Extension computes flows using Manning's equation where A = full area of the pipe, and S = slope of the invert. This option does have design abilities, but with some limits. For example, if a pipe size has been set to 0 for design, Hydraflow Storm Sewers Extension cannot size it because it does not know the flow rate, Q. In this case, it sets the pipe size equal to the minimum size as set in the Design Codes. Pipe inverts and slopes are set by the same methods as in the other calculation options, using Manning's equation and the design velocity.

Design Options As mentioned above, Hydraflow Storm Sewers Extension will automatically design a pipe size and/or invert elevation when it encounters a zero values for these during calculations. Occasionally you will find it convenient to reset all of the pipe sizes to zero but hold the inverts or visa versa. These options allow you to do just that. The actual reset doesn’t take place until after you click [Ok].

Starting HGLs This entry contains a table with rows for each outfall in your system. Invert Elevation Down This typically is already set but you can modify it here. Known Elevation Enter a known elevation in the drop-down list box corresponding to the Line Number, Line ID, etc. This is the elevation of an existing tailwater from where the HGL calculations begin... the downstream end of the outfall line. Note that this elevation cannot begin below critical depth. If you set this below critical depth, Hydraflow Storm Sewers Extension will automatically reset it to critical depth. If you do not know what it is, you should select one of the following options.


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Crown This sets the tailwater at the crown of the downstream end of the line. Normal This sets the initial tailwater at normal depth (per Manning’s Equation) of the line. Be careful on steeply sloped pipes in that normal depth is less than critical. Hydraflow Storm Sewers Extension will bump up the starting HG to critical depth in these cases. Critical This sets the initial tailwater at critical depth (min. specific energy) of the line. (dc + D)/2 New with Hydraflow Storm Sewers Extension, this option follows the starting HGLs used in HDS-5 and is (Critical depth + Diameter) / 2.

User Options Use Interactive Feature In all situations, Hydraflow Storm Sewers Extension automatically analyzes and designs your system as needed without any interaction. There are times, however, when you may want to make changes during the process. This interactive design module is used for such occasions.

Critical

Normal

Crown


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Hydraflow Storm Sewers Extension’s Interactive Design screen brings you and the project data closer together. Assures your work is done right the first time. Hydraflow Storm Sewers Extension automatically displays an interactive design screen when you set the user option, "Use Interactive Feature" to on. This feature is not available for the EMS or Capacity calculation options. It allows you to modify the design on the fly. Even when using "Full Design", you can immediately see how the modifications affect the computed HGL.

► Here's how it works… During the calculation process, Hydraflow Storm Sewers Extension plots the current line or inlet that it's working on. Hydraulic information about this line is displayed on the top table. The items in the bottom table are available for you to modify using the spin button control on the right. The spin control will increment or decrement the data item which has the focus, i.e. the one with the yellow background color. You can set the focus of other data items in the table by clicking on them with your mouse. Once Hydraflow Storm Sewers Extension sets the inverts and pipe size, it plots it. You can then redesign, resize the line, raise or lower the inverts individually or together, realign the pipe with its downstream or upstream lines. You can also realign the up or downstream ends with the Minimum Cover line. (Green dotted line) Each time a modification is made, Hydraflow


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Storm Sewers Extension updates the calculation so you can immediately see the results. Once you are ready to accept the current design, you can move on to the next line. Again, you oversee the design as it progresses, making whatever changes you need. You can proceed this way until the end or you can click [Finish] at any time to skip interacting with the remaining lines. You are free to move back to any previous lines as well as forward. Hydraulic information about the current line is displayed at the top of the screen but is for informational purposes only. It cannot be modified. Note that HGL data will be appended with an “i” when flowing under inlet control and a “j” when the line contains a hydraulic jump. In addition to the pipe data, Hydraflow Storm Sewers Extension allows you to interact with any inlets you may have. You can freely switch from the line profile, inlet section and plan view.

Below is a description of each of the controls on each screen.

The Slider control allows you to increase or decrease the sensitivity or increments of the spin buttons. This control is located to the left part of the screen. The minimum is .01 while the maximum is 1.0. Each time a spin button is clicked, the

respective value will change by the amount set in this control. For example, you might want to set the value to 1.0 when adjusting inlet throat heights or to 0.01 when adjusting invert elevations. Note that the Slider control is not used when changing pipe sizes. In addition, the control value is divided by 10 when adjusting gutter slopes and inlet cross slopes Sx & Sw.


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Navigation Controls Each screen display, Profile, Inlet Section and Plan, has common navigation controls which allow you to move throughout your system. A brief description follows:

Undo Feel free to make any modifications as you wish. There’s always a backup available. Simply click the [Undo] button to return to the line’s original data. Design This button aborts the current modifications and completely redesigns the line size and invert elevations using the calculation method, “Analysis w/ Design”. In other words, the pipe size and invert elevations are reset to zero and are designed per the Codes. It redesigns the inlet when viewing the Inlet Section. Up After making modifications, click the [Up] button and Hydraflow Storm Sewers Extension will proceed to the next upstream line. Click the [>] button to go to the last upstream line. Down To go back to a previous line click the [Down] button. Click the [<] button to go to Line 1. Finish To skip the interactive design process at any time, click the [Finish...] button. Hydraflow Storm Sewers Extension will finish the design bypassing any user interaction. Cancel Click this button to cancel this operation. If you have already gone through a portion of the system, you'll need to Undo Compute to restore the previous values back at the Main Menu. As mentioned above, the items in the bottom table are available for you to modify using the spin button control on the right. The spin control will


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increment or decrement the data item which has the focus, i.e. the one with the yellow background color. You can set the focus of other data items in the table by clicking on them with your mouse. Zoom Controls

Hydraflow Storm Sewers Extension has three zoom options which enlarge, reduce and reset the drawing scale. Zoom In: This feature allows you to enlarge the drawing. To enlarge the drawing, click the [Zoom In] button. The mouse cursor will change its shape to a cross-hair centered inside of a red rectangle. This rectangle represents the scale limits of the enlarged drawing. Move the rectangle with your mouse to the area you want to enlarge and then click your left mouse button. Hydraflow Storm Sewers Extension will then redraw the system to an enlarged scale. Repeat this process to enlarge further. Zoom Out: Clicking the [Zoom Out] button enlarges the drawing extents. Repeat as desired. Reset Scale: When Hydraflow Storm Sewers Extension draws your system on the screen, it selects a scale such that the entire system will be displayed. To redraw the system to this default scale, click the [Reset] button. Open Codes

Occasionally you may need to review the current settings in the Design Codes. This button opens the Codes window. Be aware that when making changes in the Codes will only affect the current line and upstream lines. To make those changes global, you’ll need to move downstream to Line 1 and proceed back upstream. Show EGL (Profile View Only)

This button toggles on/off the Energy Grade Line. When on, the EGL will plot as a black dotted line.


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Print

The print button will send a hard copy of your display to your printer. What follows are descriptions for each of the three display styles.

PROFILE

Size The pipe size is incremented or decremented (commercially available sizes only) by using the spin control. Note that if this line is a box or elliptical section, this item changes the "Rise" only. Barrels You can increase / decrease the number of pipe barrels. Four max. Invert Down / Down & Up / Up Click on the spin button, up or down, to increment or decrement the highlighted invert variable by an amount set by the slider control. When Down & Up has the focus, both inverts are changed. Inlet/Rim Elevation Click on the spin button, up or down, to increment or decrement the highlighted inlet/rim elevation variable by an amount set by the slider control. Known Q Use this to add or subtract flow from the system. This can be very useful for extracting Q in order to lower the HGL to a specific level. Be aware that the Known Q also affects inlets and it’s possible to zero-out the overland flow to the inlet. If this is an issue, globally edit the junction types temporarily to Manholes.


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Pipe Alignment When clicked, this option adjusts the line's invert elevations to conform to the Design Code's "Design Alignment" settings. For example, modifying the pipe size can cause the pipe crowns to go out of alignment. Clicking this button resets the new pipe to match the crown of the line. Note that this control only affects the Invert Elevation value which has the focus. For example, when the Invert Dn has the focus, this button will realign the downstream invert only.

Cover Alignment Click this button to move the pipe up/down to match the minimum cover line. The minimum cover is the dotted green line. Note that this control only affects the Invert Elevation value which has the focus. For example, when the Invert Up has the focus, this button will realign the upstream invert only.

Lock Inverts Lock this in to hold the invert elevations while adjusting something else such as the pipe size. Typically, if unlocked, adjusting a pipe size will cause the crown to stay in place and the inverts to lower. When locked, the crown will move up or down instead.

Carry Edits Up/Down This handy tool will carry the invert edits in the up or downstream directions to other connecting lines. If, for example, you raised the upstream invert elevation of a particular line by 1 foot in order to avoid a conflict of sorts. This would render other upstream lines a foot below. By clicking the Carry Edits Up button, all lines in the upstream direction will also raise by 1 foot. ______________________________________________________________ Note When carrying edits downstream only lines in the direction of flow will be affected. In other words the change goes only with the flow, not the numbers. ______________________________________________________________


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INLET SECTION

New with Hydraflow Storm Sewers Extension is the ability to interactively modify inlet parameters. This feature brought new light to inlet analysis providing you with a better understanding of the methodology, variables involved, and how they affect the interception capacity of inlets. In some cases you may be surprised. For example, what little affect Throat Height has on Curb Inlets on grade. Or the dramatic affects of changes in cross slope and local depressions on the same type of inlet. Similar to the Profile view, highlight the data cell you’d like to edit and then activate the Spin control to increase or decrease its value. Note that the increments will be equal the Slider control value with the exception of the Gutter properties, Sl, Sw & Sx. Those increments will be equal to the Slider value / 10.


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Image Controls

These controls allow you to manipulate the views of the drawing. They function differently, however, depending on whether you are in 2D or 3D mode. Two or Three-Dimensional To view the inlet in 2-dimensions, click [2D]. Likewise, click this button again to toggle back to a 3-dimensional view. Spin Buttons - While in 2D these independently increase or decrease the X & Y scales. In 3D view they move the location of the center of projection. Note that the allowed magnitude of movement is limited for practical reasons. Tip: You may modify the X or Y scales of the 3D view by first changing them in the 2D mode and then switching to 3D. Reset – Resets the drawing scale to the default.

PLAN Activate the plan view by clicking the [Plan] tab button. This screen is primarily for informational and navigational purposes. It does not allow user-interaction with data variables.


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When using the navigation controls, Hydraflow Storm Sewers Extension follows the flow path and not necessarily the line numbering sequence. However, to quickly jump to a particular line, just click on the Line’s junction icon (must be visible). Then switch to the Profile or Inlet Section screen for editing. You’ll also note that while using the navigation controls, Hydraflow Storm Sewers Extension follows the flow path and not necessarily the line numbering sequence.

Computing Summary In summary, calculation options "Analysis and Design" and "EMS" analyze existing systems and designs those parameters that have been left out (set to zero) while not considering the minimum depth requirement. The "Full Design" option resets the whole system and designs from the upstream down using the minimum depth as an additional design constraint. Use the "Capacity Only" option when all you want to know are the full-flow capacities of the system. The Interactive screen will always begin at Line 1 but feel free to move to the upstream end and work back down. ______________________________________________________________ Note Once a system has been designed, Hydraflow Storm Sewers Extension considers it to be an existing system. ______________________________________________________________ When finished, final results are displayed on the Results tab. From there you can print reports, plot lines, inlets and profiles.

Computed Results Immediately after calculating, Hydraflow Storm Sewers Extension displays the final results in the "Results" tab. This tab has seven different styles of reports including a custom report. To select a particular style, click on the corresponding style button along the top of the tab. The six styles of screen reports, Summary, DOT Style, Inlet, FL-DOT, Calculation and Cost reports are preformatted while the Custom is designed by you.


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Important! While viewing the results you will notice a sign [COMPUTE] to the right of the report selector buttons. This light indicates the status of the results. If the light is off, the displayed results reflect the current input data. If you later decide to edit the input data, this sign will turn on indicating that you may need to re-compute to make the reports current. There are many row and column formatting options available on the Results tab.

Freezing Columns There will be occasions when you will need to scroll the report to the left to view certain columns. When doing this, the columns on the left will scroll off the screen. You may wish to hold the Line No. column so you can tell which line you are viewing. You can freeze any number of consecutive columns so that they stay in place when scrolling. To freeze a column, you must start with the left-most column. Move your mouse pointer over the first, non-frozen column, typically the Line No. column to start, but not over the column heading. As you move the pointer towards the left, you'll see the pointer change to a lock icon. At this point, drag the pointer to the right the number of columns you want frozen. Release the mouse button when desired. To unfreeze, repeat the process in reverse.


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Moving Columns Hydraflow Storm Sewers Extension allows you to move any of the columns. To move a column, position your mouse pointer over the desired column heading. The pointer will change to an arrow with a box at the bottom. At this point, drag the column either right or left to the new position as desired. Release the mouse button to accept.

Resizing and Deleting Columns You can resize any column by positioning your mouse pointer over a column line in the heading. The pointer will change to a sizing cursor. Simply drag the column line to a new position to accept. Delete columns by resizing the column to a zero width.

Selecting a range of lines Hydraflow Storm Sewers Extension has many graphing options explained later in this chapter. You may need to plot a profile of a range of lines in your system. You can pre-select these lines at the Results tab by simply dragging your mouse pointer across the range of lines. Selected lines will be highlighted.

Refreshing the Results Grid

In order to restore the grid to its original condition, refresh the display by clicking on the [Refresh] button on this tab. This will not affect frozen columns.


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You can pre-select these lines at the Results tab by dragging your mouse pointer across the range of lines.

Change the Order

By default, the results are displayed in ascending order… starting with Line 1 at the top row. You can reverse this order by clicking the [Reverse Order] button.

Printing the Results Grid

Hydraflow Storm Sewers Extension allows you to quickly print the current grid display. Please note that this feature is not the same as the formal reports, however, they are very similar. The advantage to printing them here is that it is WYSWYG. All formatting will be reflected on the print-out. To print, click the [Printer] button on this tab. A print dialog box will appear to allow specifying a printer, number of copies, etc. For better looking reports, use the [Report] button on the top tool bar.

Exporting the Results Grid While viewing, you can save a report to a comma-delimited or tab-delimited text file for importing into other programs such as spreadsheets, word


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processors, or perhaps your own program for further processing. Exporting can be accomplished by selecting "Import/Export / Export Results" from the "File" menu. Then select either Comma-delimited or Tab-delimited text file. Hydraflow Storm Sewers Extension will display a "Save As" dialog box. Specify a file name, directory, drive, etc., and Hydraflow Storm Sewers Extension will save the report. Note that exported files will have a ".txt" extension. The following is a brief description of each of the reports.

Summary Report Select this screen report style by clicking the [Summary] button on the Results tab. This report displays the results in a summary form.

Summary Report. Use the vertical and horizontal scroll bars to view any hidden data. The data items are fairly self explanatory. Note however that the minor loss is the junction loss at the upstream end of the line. HGJ is the HG in the junction, HGL UP + Minor Loss. An asterisk "*" in the HG column indicates that the line is flowing under pressure, i.e., the HGL is above the crown. An “i” suffix indicates the line is


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flowing under inlet control. A “j” suffix indicates the line contains a hydraulic jump.

DOT Report This report resembles a traditional Department of Transportation tabulated report. Use the vertical and horizontal scroll bars to view any hidden data. The data items are fairly self explanatory. Note the Total Flow can be more or less than the Capacity. The capacity is simply Q based on Manning's equation with full flow. This equation assumes the slope of the energy grade line, EGL, is equal to the slope of the invert. This is seldom the case in real situations. If the slope of the EGL is greater than the slope of the invert, chances are that the total flow is greater than the full flow capacity. On the other hand, if the slope of the EGL is less than the slope of the invert, the total flow can be less than the full flow capacity and the pipe could be flowing full.

Dot Report ______________________________________________________________ Note It is also important to recognize that the Total Flow may not equal the flows computed by Total Runoff + Additional Q. There is a setting in the Design Codes, “Use inlet captured flows in system”. When this has been set to ON, the Total Flow in this report and others, will equal that which was actually captured by the inlet(s). ______________________________________________________________


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Inlet Design Report This report is dedicated to the inlet analysis only. Note that certain cells in the table are filled with "-----". In these cases, the intended data does not apply. The column, "Q = CIA" also includes any additional or Known Q's added. Also note that the Inlet Spread refers to the spread width at the inlet, while the Gutter Spread refers to the gutter just upstream of the inlet.

Inlet Report Thus, for inlets in a sag or those with equal Sx and Sw's will have equal inlet and gutter spread widths.

FL DOT Report This report has been modeled after the state of Florida Dept. of Transportation. It uses the built-in runoff coefficients specified in the "Design Codes", C1, C2, and C3. The columns labeled, Actual Velocity, Design Velocity, Actual Capacity, and Design Capacity may be confusing. They are: Actual Velocity The average of the upstream and downstream velocities.


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Design Velocity The velocity of the pipe at the Design Capacity. Actual Capacity The actual flow in the pipe. Design Capacity The full-flow capacity of the pipe per Manning's equation. If you were to compute the system using option 4, "Capacity Only", these values would report as equal.

FL-DOT Report with the Line No. column frozen

HGL Calculation Report This report provides a line-by-line tabulation of the hydraulics of the system. A complete description of the procedure is available as a hard copy print-out. Note the following footers on this report as well as others: ** Critical Depth – Indicates the depth is at critical i – Inlet Control – Indicates the line under inlet control


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j – Line contains hydraulic jump Depths and HGL/EGL values will be appended with the above signs when these conditions exist.

HGL Calculation Report.

Cost Report

This report provides a detailed list of the pipe quantities along with their cut depth quantities and associated costs. The totals are shown on the last row and column.

Click the report selector to view other Scenarios.


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Cost Report

Custom Report The customizable report allows you to create your own reports. Basically, you specify what variable appears in each column. These reports can be printed and exported, just like the other preformatted reports. You have over 95 independent variables to choose from. If the variable doesn’t appear in this list, you probably don’t need it! Custom report layouts can be saved and loaded at any time so you may have as many unique layouts as you wish. For example, you might want to create one report for the local city drainage authority and another for the county or state. Use this custom report when the other preformatted reports don’t quite “fit the bill”.

Creating Your Own Custom Report

To create your own report, click the Custom Report Edit button (Ellipsis) next to the Custom Report button on the Results tab. The following screen appears.


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Create your own reports with over 95 independent variables. Hydraflow Storm Sewers Extension automatically loads the most recently used custom report at startup, similar to the IDF curves. The basic concept is to build your report by selecting the desired variable from each column’s drop-down list box. You can add and delete columns using the two [Add Col] [Del Col] buttons just beneath the report table. The text box between these two arrows indicates the total number of columns being used. Use these buttons to insert or add and to delete columns in the table. To insert or delete a specific column, first select the column by clicking on it with your mouse and clicking the insert or delete button.

By clicking on the column head, a drop-down list box appears with the available variables. These variables can be used on all columns.


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Each report can have up to 100 columns. Variables can be repeated if desired. The first column, Line No. is fixed and must be a part of all reports. It cannot be deleted. Described below are all of the options and features of the Custom Report along with a description of each of the variables. Along the top of the Custom Report form is a small toolbar containing the following buttons:

[Clear] Use this to clear the entire table before creating a new report. [Open] Hydraflow Storm Sewers Extension allows you to save and load any previously built custom reports. Use this to open a previously saved report. [Save] Click this button to save the current report. You will have a choice of what to save as and where. These files will have a “.rpt” extension. [Help] Opens the help screens Report Name Enter a name for this report. This is not the same as the name you’ll use to save. This name will appear as the custom report button label on the Results tab. Because of this, its length is limited to 9 characters. For example, MyReport is a valid report name. Steps to Build Your New Custom Report 1. Clear the existing report. Click the [Clear] button on the top tool bar. 2. Add a new column by clicking the [AddCol] button. 3. Click on the drop-down list box in the new column and select a variable.


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4. Click [Apply] to accept. Repeat steps 2, 3 and 4 as needed to complete your report. Once you have your report table setup. Enter a Report Name. Then Save. Then click [Exit] to return to the Main Menu to view.

Custom Report Variables List Following is a description of each of the variables. Most of these apply to the preformatted reports as well. Area Dn The cross-sectional area of flow at the downstream end of the line. Area Up The cross-sectional area of flow at the upstream end of the line. Bypass Line No. The line which receives bypass flows. C1, C2, C3 User-defined runoff coefficients as specified in the Design Codes. Capacity Full-flow capacity of the line as per Manning’s equation with the slope, S, set to the slope of the invert. Cover Dn The distance from the “Ground/Rim Elev Dn” to the top of the downstream end of the line. N/A if Ground/Rim Elev = 0. Cover Up The distance from the “Ground/Rim Elev Up” to the top of the upstream end of the line. N/A if Ground/Rim Elev = 0. Critical Depth The depth at minimum specific energy.


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Cross Slope, Sw The cross slope of the gutter section. Cross Slope, Sx The cross slope of the pavement section. Curb Length The length of opening for curb and drop curb inlets. Deflection Angle Angle between the line in question and a line projecting upstream of the downstream line. Angles to the right are positive, left are negative. Depth Dn Depth of flow at the downstream end of the line. Depth Up Depth of flow at the upstream end of the line. Downstream Line No. The number of the line, the line in question connects to at the downstream end. Drainage Area Area of land contributing to runoff for the line or inlet in question. Not a total. Easting, X The X, or Easting coordinate of the upstream end of the line. EGL Dn Energy grade line at the downstream end of the line. HGL Dn plus velocity head. EGL Up Energy grade line at the upstream end of the line. HGL Up plus velocity head.


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EGL Junct Energy grade line in the junction at the upstream end. HGL Jnct plus Velocity Head Up. Equals HGL Jnct when under Inlet Control. Energy Loss Energy loss due to pipe friction. Equals the average friction slope times the line length. Flow Rate The flow, Q, used to calculate the HGL in the system. Friction Slope Ave Average slope of the energy grade line, or S, per Manning’s equation. Friction Slope, Sf Dn The slope, S, per Manning’s equation using the parameters at the downstream end of the line, depth, area, wetted perimeter, etc. Friction Slope, Sf Up The slope, S, per Manning’s equation using the parameters at the upstream end of the line, depth, area, wetted perimeter, etc. Grate Area The clear opening area of the inlet grate. Grate Length The longitudinal length of the inlet grate. Grate Width The transverse width of the inlet grate. Ground/Rim Elev Dn The elevation of the ground/rim as entered for the downstream line of the line in question. Ground/Rim Elev Up The elevation of the ground/rim as entered at the upstream end of the line in question.


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Gutter Depth Depth of flow in the gutter, upstream of the inlet. Gutter Slope Longitudinal slope of the gutter. Gutter Spread Width of flow in the gutter, upstream of the inlet. Gutter Width The transverse width of the gutter. HGL Dn Hydraulic grade line at the downstream end of the line. HGL Up Hydraulic grade line at the upstream end of the line. Does not include the minor loss. HGL Jnct Hydraulic grade line in the junction at the upstream end of the line. This value is equal to HGL Up plus the minor loss. HGL Jump Up The elevation of the water surface at the initial depth (upstream end) of a hydraulic jump. HGL Jump Dn The elevation of the water surface at the sequent depth of a hydraulic jump. Hw Headwater. The elevation of the HGJ minus the invert elevation upstream. Incr CxA Runoff coefficient, C, times the Drainage Area for the individual catchment. Incr Q Incr CxA times Intensity. Also known as Q catchment or runoff to the individual inlet.


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Inlet Depth Depth of flow at the inlet face. Inlet Efficiency Q Captured / Q Catchment expressed as a percentage. Inlet ID User defined text to describe the inlet. Inlet Location Sag (Gutter Slope = 0) or on grade (Gutter Slope > 0). Inlet Spread Width of flow at the inlet. Inlet Time User defined travel time of the Drainage Area. Intensity System The computed intensity at a given point or node in the pipe system based on Tc. Intensity Inlet The computed intensity at a given inlet based on Inlet Time. Invert Dn Invert elevation at the downstream end of the line. Invert Up Invert elevation at the upstream end of the line. Jump Loc Location of the hydraulic jump. Equals the distance from the downstream end of the line to the sequent depth. Jump Len Length of the hydraulic jump. Distance upstream from the sequent to initial depth.


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Junction Loss Coeff. User defined value multiplied by velocity head to compute minor loss. Refers to the upstream end of the line. Junction Type Manhole, Curb Inlet, Headwall, etc. Known Q User defined. Any additional known flows to be injected into the system at the upstream end of the line. Also is added to inlet flows. Line Cost The total cost of the line as per the cost codes. Line ID User defined description for the line. Line Length Length of the line from center-to-center of junctions. Line Size The line Rise and Span reported in one column. This will include Multi-barrels. Line Slope Slope of the line. Invert (Up – Invert Dn) / Line Length. Expressed as a percentage. Line Type Circular, Elliptical or Box section. Local Depression User defined. Amount of depression for the inlet. Measured from the projection of Cross Slope, Sx. Mannings n Gutter N-value of the gutter section.


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Mannings n Pipe N-value of the line. Minor Loss Junction Loss Coeff. x Velocity Head Northing, Y The Y, or Northing coordinate of the upstream end of the line. Pipe Travel Time Equals Line Length / Velocity Ave. Can be suppressed to zero in Design Codes. Q Bypass Flow that is not captured by an inlet and bypassed to the bypass target line. Q Captured Flow that was captured by the inlet. Q Carryover Q Bypass from an upstream inlet. Rise Vertical distance of the pipe. Runoff Coeff.(C) Rational method runoff coefficient. Span Horizontal distance of the pipe. Storage The volume of the flow in the line based on actual depths. Subarea, A1, A2, A3 The drainage area corresponding to C1, C2, and C3 for the catchment in question. Tc Time of concentration


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Throat Ht Vertical distance of the inlet throat opening measured from the projection of cross slope, Sx. Total Area Total drainage area contributing to flow at a given point in the system. Total CxA Sum of incremental CxA’s up to a given point in the system. Total Runoff Total CxA x Intensity System. User Sta Dn / Up User-defined stations. Velocity Ave Average velocity in the line. Velocity Dn / Up Velocity at the downstream / upstream end of the line. Velocity Head Dn / Up Velocity head at the downstream / upstream end of the line. (V2/2g) Velocity Head Jump Dn / Up Velocity head at the sequent and initial depths of the jump respectively.

Printing Reports Any of the above screen reports can be printed in hard copy in a WYSWYG fashion. However, more formal reports are available at Hydraflow Storm Sewers Extension's print menu. Most of these reports are similar to the screen reports as described above. To print a report, click the [Reports] button on the upper toolbar or select "Print ..." from the "File" menu. The following dialog box will appear.


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Hydraflow Storm Sewers Extension's reports menu. Note the Project Name on the window title bar.

Project Name Hydraflow Storm Sewers Extension will add a user-defined project name to your reports. The Project name is specified at the Main Menu in the Edit pull-down menu.

Reports Select a report style by checking the appropriate box. If the computations are not current with the input data, excluding the Inventory and structures reports, you will not be able to select these reports for printing. Re-compute to enable printing when necessary.

Options A range of lines can be selected for printing. For example, if your system contains 20 lines but you only wish to print lines 5 through 16, you can specify this range in the "From" and "To" boxes. This option does not apply to the Plan View. Enter the number of Copies of each report to be printed. Hydraflow Storm Sewers Extension typically prints reports starting from Line 1 working upstream. You can reverse the direction by clicking the "Print upstream to downstream" checkbox.


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Note: When needed, Hydraflow Storm Sewers Extension automatically sets the orientation of your printer on "Landscape" before printing. This allows Hydraflow Storm Sewers Extension to better fit the information on a single 8-1/2 x 11 inch sheet. To begin printing, click [Print…]. To see a preview first, click [Preview].

Plotting Graphs Hydraflow Storm Sewers Extension offers two types of plots, 1. A multipurpose Line Plot with a single-line drawing, inlet and plan; and 2. Profile plot.

Line Plot A line plot is a drawing of an individual line that shows a profile view. Also included are inlet sections and a plan view. To draw a Line Plot, select a line from the main menu and click the [Plot] button on the upper toolbar. If the results are current, a variety of line properties are displayed at the bottom of the screen. Note that HGL data will be appended with an “i” when flowing under inlet control and a “j” when the line contains a hydraulic jump.

Navigation Controls Use the directional arrow buttons to move from one line to the next. Note that Hydraflow Storm Sewers Extension will move in the direction of the flow and not necessarily by line number.


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|< Home Click this button to plot Line 1. < Back This button moves to the next downstream line. > Next Click the "Next" button to move upstream by one line. >| End This button takes you to the last (most upstream) line. Show EGL (Profile View Only)

This button toggles on/off the Energy Grade Line. When on, the EGL will plot as a black dotted line. Print

The print button will send a hard copy of your display to your printer. Preview is not available on individual line plots.

Zoom Controls

Hydraflow Storm Sewers Extension has three zoom options which enlarge, reduce and reset the drawing scale. Zoom In: This feature allows you to enlarge the drawing. To enlarge the drawing, click the [Zoom In] command button. The mouse cursor will change its shape to a cross-hair centered inside of a red rectangle. This rectangle represents the scale limits of the enlarged drawing. Move the rectangle with your mouse to the area you want to enlarge and then click your left mouse button.


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Zoom Out: Clicking the [Zoom Out] button enlarges the drawing extents. Reset Scale: When Hydraflow Storm Sewers Extension draws your system on the screen, it selects a scale such that the entire system will be displayed. To redraw the system to this default scale, click the [Reset] button.

Looking downstream, Line Plot showing the Inlet Section in 3D. This plot is also available in 2D. Line Plot is similar to the Interactive feature in that it has the ability to plot inlet sections as well as navigable plan views.

Profile Plot To draw a profile, click the [Profile] button on the upper toolbar.

Note You can first select a range of lines by dragging your mouse across the desired lines on your Results tab. Then click [profile]. ______________________________________________________________


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Hydraflow Storm Sewers Extension's profile plot. You can first select a range of lines from the Results tab by dragging your mouse across the desired lines. Hydraflow Storm Sewers Extension will draw a horizontal profile of lines from the "Start line" to the "End line". The upstream and downstream line numbers are user definable. The profile is automatically drawn from left to right working upstream. In other words, the profile is drawn only as the water flows. Hydraflow Storm Sewers Extension ignores any branches in the range of lines selected. To draw or re-draw a range of lines, select the line numbers from the drop-down list boxes and then click the [Redraw] button.

Scaling Options

Hydraflow Storm Sewers Extension automatically establishes the x & y scales of the profile drawing, however many options are available to manipulate your profile drawing scale.


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Y Min The elevation where the Y-scale begins. To change this value, type in the new elevation and click the [Lock] button to set. To revert to the default scale, unlock. Y Max The maximum elevation of the Y-scale. To change this value, type in the new elevation and click the [Lock] button to set. To revert to the default scale, unlock.

Y-Axis Ticks (Spin button) You can increase or decrease the number of y-scale tick marks on the plot by using this spin button located to the right of the Y-Max Lock. XIncr This is the horizontal scale selector. Choose a desired scale from the drop-down list box. Next, click the adjacent [Lock] button to set and redraw at the new scale. To revert to the default scale, unlock.

X-Axis ticks (Spin button) You can increase or decrease the number of x-scale tick marks on the plot by using this spin button located to the right of the XIncr Lock.

Label Options The Label Options toolbar allows you to toggle on/off many different drawing parameters.

Junction labels and leaders

Pipe labels

Text size

Hydraulic Grade Line

Natural ground, Rim elevations

Horizontal grid lines

Vertical grid lines


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User-defined stationing (See, “Line & Inlet Data” this chapter for more information)

Zoom Functions You can zoom in on this plot any time by simply dragging your mouse from the upper left to the lower right of the desired extents.

Draw a rectangle representing the zoom extents

Click [Redraw] to return to full scale view

Exporting to DXF This option will export the current plot as a ".DXF" file for use in CAD programs. To export the Profile, click the [Export] button. The following options screen will appear.


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Horizontal Scale - Select a horizontal scale for the exported profile from the drop-down list box. Vertical Scale – Type in a vertical scale. Text Scale Factors – Depending on the intended use of the dxf file, you might want to scale the text up or down to better fit the sheet size. Border – This option will draw a border around the profile. Click [Ok]. Next, enter the name of the file you wish to export. Labels, lines, etc. will be assigned individual layers so that you can use or delete them as needed.


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Sample DXF file as imported in a CAD program(zoomed view).

Import & Export DXF / XML Files

Hydraflow Storm Sewers Extension allows you to import and export from .DXF and LandXML data files plan layouts and background images. Most popular CAD programs such as AutoCAD produce both .dxf and LandXML files thus providing a seamless connection between Hydraflow Storm Sewers Extension and many other cad programs. Once your system is designed, Hydraflow Storm Sewers Extension lets you export your projects back to dxf and xml formats. Below is a detailed description of each feature.

Importing .DXF Files

Background Maps

Rather than draw your system in your cad program, Hydraflow Storm Sewers Extension allows you to import a background dxf file. This will aid in the accuracy of the pipe alignments as you draw your system layout. Background images can come from any standard .dxf file but are limited to Line, Polyline, LWPolyline, Arcs and Circles. Line weights, certain entity types as well as Blocks and Text are not supported in order to maintain a high processing speed of redraws. To import a background map, click [DXF Import] on the top tool bar and select “Background Image from DXF…”.


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Next, enter the name of the file you wish to import. It must have a .dxf file extension. Hydraflow Storm Sewers Extension will read the file and display the results on the Plan View. Below shows a sample map imported from a dxf file.

A background image from DXF. Once imported, use the zoom and crop buttons to modify your background image. Note the zoom extents button at the far right of the Plan View toolbar zooms to the full background drawing extents. Cropping the Background Image

The Crop tool allows you to visually customize the background drawing extents. To use, click the crop button. The mouse cursor turns into a crosshair. Next, click the lower left corner of the image. Then click the upper right. To cancel, right-click your mouse.


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Matching Your Background with Your Existing System If importing a background after you have drawn your pipe layout, you can move your pipe system to match or correlate the background image. Do this by dragging the outfall (downstream end of line 1) to the desired coordinates or position. Clearing the Background Image Clearing the background image is done from the options pull-down menu. To clear the image, select “Options / Plan View / Background Image / Clear”. Auto Redraw While editing and/or drawing your lines, Hydraflow Storm Sewers Extension must redraw any loaded background image with every move of your mouse. In most cases, it is not noticeable. However, complex background images may require a lot of redraw time and can slow you down. To overcome this, you can turn off Hydraflow Storm Sewers Extension's auto redraw feature. When off, Hydraflow Storm Sewers Extension will only refresh the background image on mouse-up events. This feature can be toggled on/off and is accessed by selecting "Options / Plan View / Background Image / Use Auto Redraw" from the main pull-down menu. ______________________________________________________________ Note Hydraflow Storm Sewers Extension does not save DXF background images with project files, rather it saves its name and location, i.e., C:\Program files\Hydraflow Storm Sewers Extension for AutoCAD Civil 3D 2009\mydxfbackground.dxf. Upon opening a project file (.stm) that had a background image, Hydraflow Storm Sewers Extension simply reloads the dxf


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file and positions the pipe network layout as it was when last saved. Therefore, if transporting your .stm file, be sure to also include any background images. Hydraflow Storm Sewers Extension does, however, save LandXML background images with the .stm project file. ______________________________________________________________

DXF Plan Layouts Hydraflow Storm Sewers Extension can import a plan layout of up to 250 lines. You can have Hydraflow Storm Sewers Extension merge this imported file with your existing plan or start a new plan. If you merge, be sure the total number of lines does not exceed 250. You can also import invert elevations if needed. Once imported, Hydraflow Storm Sewers Extension computes their lengths, downstream line numbers and deflection angles and assigns them to the corresponding alignment data. All you need to do after that is edit the lines providing the missing data such as the flow data, junction type, etc. Important! Before importing your plan, the following conditions must be met: 1. The line segments must be drawn in your CAD program as "Single Line" segments or "Polylines". 2. The individual lines must be drawn in the upstream direction. 3. The order in which the lines are drawn does not matter except that the first line drawn must either be Line No. 1 or the last line in your system. 4. It is recommended that you use the CAD program's Snap feature, i.e., the line segment's coordinates must connect. Hydraflow Storm Sewers Extension will connect them if they are within 2 feet of each other, but it is best to use the Snap mode. 5. It is recommended that you specify a layer name in your CAD program other than the number 0, or any number. AutoCAD uses 0 as its default layer name and can sometimes confuse Hydraflow Storm Sewers Extension. Try to begin the layer names with a character, not a number. 6. You can only import one system (one outfall) at a time. If you want to import multiple systems, you’ll need to do them separately.


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To import a plan layout, select "File / Import/Export / Import / Pipe Layout from DXF..." at the Main Menu. Next, enter the name of the file you wish to import. It must have a .dxf file extension. To import a plan layout, select "File / Import/Export / Import / Pipe Layout from DXF..." at the Main Menu. Next, enter the name of the file you wish to import. It must have a .dxf file extension. Layer Name Select the name of the Layer that was used in your CAD program. Click the Layer Name list box to show all of the available layers. Then click the desired layer name. New Layout Click this option button for a new project. Merge to Existing Click this option button if you want Hydraflow Storm Sewers Extension to add the imported file to the current project file. Next, select a line number to connect to or choose, “New Outfall”. Include Elevations Click this option box if you have assigned invert elevations (Z- coordinates) to each of the line segments and you want Hydraflow Storm Sewers Extension to include them in the import. When finished, click the [Import] button. If all goes well, Hydraflow Storm Sewers Extension will import the file and return to


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the Main Menu with the new layout in place. Complete the input data by editing. You may need to click the zoom [Reset Scale] button to view the drawing when merging plans. If something goes wrong Hydraflow Storm Sewers Extension reads your DXF file and tries to piece together the network by connecting line segments with similar (+ or - 2 feet) coordinates. In the end, there should only be one line that it couldn't connect... Line 1. If Hydraflow Storm Sewers Extension cannot configure your import file, it's probably due to the lines not being drawn in the upstream direction or if two or more lines couldn't be coordinate-matched. Check your import file for these violations and try again. Hydraflow Storm Sewers Extension will attempt to import all of the lines until an error is found. When importing, Hydraflow Storm Sewers Extension assumes the import file to be in the current units setting, U.S. Customary or SI.

Exporting DXF Files Hydraflow Storm Sewers Extension also allows you to export your Plan plots and Profile plots as DXF files. Exporting Plan Views To export a plan layout, select "File / Import/Export / Export / Export Plan to DXF" at the Main Menu. Next, enter the name of the file you wish to export. Note that the labels, lines, etc. will be assigned individual layers so that you can use or delete them as needed. Exporting Profile Plot See "Plotting Graphs" above.

Importing LandXML Files Hydraflow Storm Sewers Extension can import and export LandXML data files. LandXML is a data file, sort of a cross between DXF and html files. Its purpose is to facilitate the exchange of data created during the land planning, civil engineering and land surveying process. LandXML promises to enhance productivity by allowing design teams and clients to share data across platforms quickly and seamlessly, even from remote locations. LandXML data files are independent of operating systems, computers and the vendors who create them. For example, you can create your storm sewer project in


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AutoCAD Civil 3D. Export the LandXML file (it includes the background map and pipe system) to Hydraflow Storm Sewers Extension. Run the calculations. Export back to any other LandXML supported software for final drafting. You could also create your project in Hydraflow Storm Sewers Extension and export it as a new LandXML file for importing into other LandXML-supported programs. Unlike DXF, LandXML files not only contain drawing elements such as line or pipe entities, but other attribute data like invert elevations, pipe diameters, flow rates, HGLs, etc. You might, for example, import a LandXML file containing a background map along with a proposed pipe layout developed in AutoCAD Civil 3D. The xml file is imported with the associated hydraulic data, such as HGL, flows, pipe slopes, sizes, etc. left blank. Hydraflow Storm Sewers Extension runs its calculations, updating this xml file with the unknowns, and then exports back to the cad program. LandXML, unlike dxf files, can be used by Hydraflow Storm Sewers Extension to import both background images and pipe layouts in a single step.

LandXML Background Maps Rather than draw your system in your cad program, Hydraflow Storm Sewers Extension allows you to import a background image from a LandXML file. This will aid in the accuracy of the pipe alignments as you draw your system layout. Background images can come from any LandXML file containing “Parcel” and/or “Alignment” elements. LandXML background images are saved with the Storm Sewers Extension .stm project files.

LandXML Pipe Networks You can import pipe networks from any LandXML file containing “PipeNetworks”.

How to Import LandXML To import select "File / Import/Export / LandXML…" at the Main Menu. The following screen appears. Select the Import tab if needed.


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Hydraflow Storm Sewers Extension can download LandXML files from the internet. Filename: Enter the name of the LandXML file or a valid internet url address. Use the [Browse] button as needed. Then click the [Open] button.

Opening a LandXML file for import Upon opening, Hydraflow Storm Sewers Extension parses the xml file for the following information: Project Name The name of the project as provided by the LandXML author. This is an optional item and may be blank. Project Description A description of the project as provided by the LandXML author. This is an optional item and may be blank.


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Available Pipe Networks LandXML files that contain PipeNetworks elements, will have one or more PipeNetwork systems. The individual networks are listed in the “Available Pipe Networks” list box. Simply highlight the network(s) you wish to import.

Import Options There are certain options available for importing. As described above, you can import background images (Parcels and/or Alignments) and/or pipe layouts from a single LandXML file. Selected Pipe Networks Check this option on to import the selected networks shown in the Available Pipe Networks list box. Check off to skip importing pipe layouts. The indicator box to the right of this option shows the total number of pipes (lines) contained in the selected pipe networks. Parcels as background Check this option on to import any available Parcels for a background image. The indicator box to the right of this option shows the number of Parcel elements contained in the file. Alignments as background Check this option on to import any available Alignment elements. The indicator box to the right of this option shows the number of Alignment elements contained in the file. To import, click the [Import] button. The sample below displays the LandXML file, “OlympusSubd.xml”.


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Imported LandXML project Matching Your Background with Your Existing System If importing a background after you have drawn your pipe layout, you can move your pipe system to match or correlate the background image. Do this by dragging the outfall (downstream end of line 1) to the desired coordinates or position at the Plan tab. Clearing the Background Image Clearing the background image is done from the options pull-down menu. To clear the image, select “Options / Plan View / Background Image / Clear”. Auto Redraw While editing and/or drawing your lines or moving labels, Hydraflow Storm Sewers Extension must redraw any loaded background image with every move of your mouse. In most cases, it is not noticeable. However, complex background images may require a lot of redraw time and can slow you down. To overcome this, you can turn off Hydraflow Storm Sewers Extension's auto redraw feature. When off, Hydraflow Storm Sewers Extension will only refresh the background image on mouse-up events. This feature can be toggled on/off and is accessed by selecting "Options / Plan View / Background Image / Use Auto Redraw" from the main pull-down menu.


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Exporting LandXML Files Exporting LandXML is similar to importing. To export, select "File / Import/Export / LandXML…" at the Main Menu. The following screen appears. Click the Export tab if needed.

Hydraflow Storm Sewers Extension can export your system to a LandXML file. When exporting, you have a choice of exporting as a new LandXML file or updating an existing LandXML file. Even if choosing to update an existing file, you’ll have an option to save it under a new name.

Exporting As New Select this option to create a new LandXML file. The only data required for this option is a project name, description and file name. Note that this file will contain only PipeNetwork data, not background images. Project Name Enter a name for this project. This item is optional but recommended. Description Enter a description for this project. This item is optional. Click [Export…] to export. Then specify a file name. You do not need to enter a file name at the Import/Export LandXML screen. Nor do you need to select from the “Existing Pipe Networks” list box.


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Updating an Existing LandXML File Use this option to update an existing LandXML file. For example, this could be the same file used to import the system. Updating will simply change existing data in the file, for example, flow rates, HGL’s, invert elevations, etc. If the incoming file does not contain any flow data, for example, then it cannot be updated and you should export as a new file. Important! When updating an existing LandXML file, the LineID’s are used to match the Pipe names in the LandXML file. In addition, the Inlet ID’s are used to match the LandXML Struct names. If Hydraflow Storm Sewers Extension cannot find a match, it will not export. You will get an error message to that effect. To begin, you must specify and open an existing LandXML file. Filename: Enter the name of the LandXML file to update. Hydraflow Storm Sewers Extension does not export to web addresses. Use the [Browse] button as needed. Then click the [Open] button. Upon opening, Hydraflow Storm Sewers Extension parses the xml file for the following information: Project Name The name of the project as provided by the LandXML author. This is an optional item and may be left blank. Project Description A description of the project as provided by the LandXML author. This is an optional item and may be left blank. Existing Pipe Networks LandXML files that contain PipeNetworks elements, will have one or more PipeNetwork systems. The individual networks are listed in the “Existing Pipe Networks” list box.


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Select the Pipe Network(s) corresponding to the one(s) you want to update. Then click the [Export…] button. When the Save XML dialog box appears you will have the option of specifying a new file name so as to not overwrite the existing file or simply select the same file used to open.

Saving and Retrieving Files Hydraflow Storm Sewers Extension allows you to save and retrieve your project files. It is recommended that you save your projects often while you are working on them.

Hydraflow Storm Sewers Extension’s Files Hydraflow Storm Sewers Extension uses several different files: 1. Project Files: These files are used to store all of your project data including the IDF curves, custom reports, and background images that were being used at the time the project was last saved. These files are saved in an ASCII format and can be viewed in any word processor. Project files have a ".stm" extension. Note that Hydraflow Storm Sewers Extension only stores the name and location of .dxf-based background images. 2. IDF curves: These files store the IDF curves. They have an ".idf" extension. 3. Custom Report files: The custom report files store the layout of each custom report, i.e., each report is stored in a single file. These files have an .rpt extension. 4. Initialization files: This file is named "Storm2008.ini and is used to store information about the different settings in Hydraflow Storm Sewers Extension such as the Options settings, Design Codes, Cost codes and the name of the IDF curve and custom report that was being used when the program was last run, etc. This file is automatically saved and retrieved from the file folder where Hydraflow Storm Sewers Extension resides. You will get an error message during the load or unload of this software if this .ini file cannot be found by Hydraflow Storm Sewers Extension.


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Saving Projects Hydraflow Storm Sewers Extension works much like a spreadsheet or word processor. To save a project, select "Save Project" from the "File" menu or click the [Save] button. If you are saving this file for the first time, select "Save Project As". When using "Save Project" Hydraflow Storm Sewers Extension will automatically save the project under its current name.

Opening Projects To retrieve a project, select "Open Project" from the "File" menu or click the [Open] button. Hydraflow Storm Sewers Extension will search for files that have the ".stm" extension. Note: Hydraflow Storm Sewers Extension is compatible with previous version (no earlier than v7.0) project files. However, once saved in the Hydraflow Storm Sewers Extension, they cannot be reloaded in earlier versions. Your existing files are not backward compatible. To load your previous IDF curves, simply open an old version (no earlier than v2000) *.IDF file. To do this, click the [IDF] button from the upper toolbar. Then [Open] the IDF file. Next, save the IDF file.

Working in SI Units Hydraflow Storm Sewers Extension is designed to operate in either U.S. Customary or SI units. All input data is entered in the current units setting. At any time, you can switch the current units setting. Hydraflow Storm Sewers Extension automatically performs a data conversion. To change units, select "Options / Units" from the Main Menu. Then select "U.S. Customary" or "SI". You will be prompted to confirm the data conversion. It is suggested to check the Design and Cost codes along with updating any custom reports. The Cost codes will likely need to be modified because the Cost module requires the Initial Depth and Increment to be in whole feet or meters. The conversion process will likely create fractions.


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Data Conversion Considerations For the most part, your existing data will be hard converted using the appropriate English to metric conversion factors. Pipe sizes are not hard, but soft converted. For example, converting a pipe size from 18 inches to SI renders 18 x 25.4 in/mm = 457.2 mm. Hydraflow Storm Sewers Extension rounds the result to the nearest 10 mm. For example, the equivalent metric size for an 18-inch is 460 mm. Important: This soft conversion of pipes will have an effect on the resulting calculations. This is because the cross-sectional area of the pipes are not exactly identical, thus producing a slightly different velocity and HGL.

Some Restrictions Apply When the option in the Design Codes, “Check for Inlet Control” has been checked, only the Standard Orifice Equation option can be used when working in SI units. When saving project files, Hydraflow Storm Sewers Extension saves the file in whatever the current units are. In order to retrieve these files, you must first switch the current units setting to match that of the incoming file. Hydraflow Storm Sewers Extension will prompt you in such cases.

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4. Computational Methods Standard Step Method

Hydraflow Storm Sewers Extension for AutoCAD Civil 3D 2009 uses the energy-based Standard Step method when computing the hydraulic profile. This methodology is an iterative procedure that applies Bernoulli's energy equation between the downstream and upstream ends of each line in the system. It uses Manning's equation to determine head losses due to pipe friction. The greatest benefit to using this method is that a solution can always be found regardless of the flow regime. This method makes no assumptions as to the depth of flow and is only accepted when the energy equation has balanced. Hydraflow Storm Sewers Extension uses the following equation for all flow conditions.

HLYZg

VYZg

V +++=++ 22111

2

2

2

2

Where: V = velocity in ft/s (m/s, metric) Z = invert elevation in ft (m) Y = HGL minus the invert elevation in ft (m) Friction losses are computed by:

( )2

21 hfhfHL +=

Where:

LineLengthRAK

Qnhf

m

×= ⎟⎠⎞⎜

⎝⎛

667

2

.

Where: Km = 1.486 (1.0) n = Manning's n


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A = Cross-sectional area of flow in sqft (sqm) R = Hydraulic radius

Pipe and Open Channel Flow Hydraflow Storm Sewers Extension computes the hydraulic grade line in a fashion similar to methods used for open channels. With the sewer system consisting of pipes and junctions, Hydraflow Storm Sewers Extension begins computing at the most downstream line and works in a standard step procedure upstream. This method assumes the starting hydraulic grade line elevation, HGL, is known. See "Computing the System". Hydraflow Storm Sewers Extension first assumes an upstream HGL for a given line and then checks the energy equation. If the energy equation does not balance, another HGL is assumed and the iterative process continues until the assumed HGL equals the computed HGL. The downstream or starting HGL for the next upstream line is based on the computed HGL plus any junction (minor) loss. Additionally, if the starting HGL at the downstream end of any line (except outfalls) is below the Minimum Starting Depth as set in the Design Codes, Hydraflow Storm Sewers Extension will automatically change the HGL to the Minimum Starting Depth. Hydraflow Storm Sewers Extension computes the HGL for any given line at three places:

Invert

EGL

HGLY1

Y2

HL

Datum Z2

Z1

V2/2g

V2/2g

Chapter 4. Computational Methods

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HGL Down The downstream end of the line. At the beginning of an outfall, this is a user-defined elevation. Either a known elevation, Crown, Normal Depth or Critical Depth. At all other lines it is equal to the HGL Junct of its downstream line. However, if the energy grade line (EGL Dn) is less than the energy grade line in the downstream junction (EGL Junct), the HGL Down is reset to the EGL Junct minus the velocity head. This prevents any occurrences of increasing energy in the downstream direction. Again, if this starting HGL is below the Minimum Starting Depth as set in the Design Codes, Hydraflow Storm Sewers Extension will automatically change the HGL to the Minimum Starting Depth. HGL Up The upstream end of the pipe. Computed using the Standard Step Method described above. If the option of checking for Inlet Control has been set to On in the Design Codes, and the line is flowing under inlet control, the HGL Up is equal to the HGL Junct minus the upstream velocity head. HGL Junct In the junction at the upstream end of each Line. Is equal to the HGL Up plus any minor or junction loss. If the option of checking for Inlet Control has been set to On in the Design Codes, and the line is flowing under inlet control, the HGL Junct is equal to the depth determined by the Inlet Control procedure, described below. The energy grade line (EGL) is computed as the HGL plus velocity head. If the line is flowing under inlet control, velocity at this point is zero and the EGL equals HGL.

Critical Depth Critical depth is computed using the following equation. If Dc is greater than 85% of D, then a trial and error method is used to find the minimum specific energy, i.e., critical depth. See Open Channel Hydraulics, McGraw - Hill, 1985, by Richard H. French.

⎟⎠⎞⎜

⎝⎛

×⎟⎟⎠

⎞⎜⎜⎝

⎛=

g

Q

DDc

2 25

26011

...


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Where: Dc = Critical depth D = Pipe diameter Q = Flow rate

Junction Losses Junction losses are computed by the following equation.

⎟⎟⎠

⎞⎜⎜⎝

⎛=

gVkssJunctionLo2

2

Where: k = Coefficient V = Velocity of flow exiting the junction Junction losses are not computed for lines at critical depth or those flowing under inlet control.


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Junction Loss Coefficients Hydraflow Storm Sewers Extension will automatically compute and assign junction loss coefficients based on the junction configuration when "Automatic" is on. It will select these coefficients based on data adapted from FHWA HEC No. 22. Remember, the selected coefficients will be based on the angle of the lines entering the junction at its upstream end. For bends less than 90 degrees, Hydraflow Storm Sewers Extension uses the following equation to compute junction loss coefficients.

⎥⎥⎦

⎤

⎢⎢⎣

⎡⎟⎠⎞⎜

⎝⎛ −−=

2

90901 AngleDeflectionK

If the junction is an inlet, K is multiplied by 1.5. In no case will K be less than 0.15 for Manholes or 0.50 for Inlets. For bends greater than or equal to 90: Inlets K = 1.5; Manholes K = 1.00. For Lines at ends of a branch, K = 1.00 A conservative value for this coefficient is 1.0. This assumes all of the velocity head is lost at the manhole. In other words, the junction is simply a reservoir being fed by any incoming lines. The incoming velocity is lost and converted to static head.

Supercritical Flow Hydraflow Storm Sewers Extension has the ability to compute supercritical flow profiles with hydraulic jumps automatically. When the energy equation cannot balance, Hydraflow Storm Sewers Extension initially assumes critical depth and proceeds to the next upstream line. When finished with the subcritical profile, it reverses the calculation procedure for any lines with critical depth assumed at their upstream ends, i.e. from upstream to downstream, and computes the supercritical profile.

Hydraulic Jump Hydraflow Storm Sewers Extension uses the Momentum Principle for determining depths and locations of hydraulic jumps. At each step (one tenth of the line length) during supercritical flow calculations, Hydraflow Storm Sewers Extension computes the momentum and compares it to the momentum developed during the subcritical profile calculations. If the two


144

momentums equal, it is established that a hydraulic jump must occur. There may be occasions when a hydraulic jump does not exist or when it is submerged. The condition which must be satisfied if a hydraulic jump is to occur is

21 MM =

Momentum, M, of the subcritical profile equals the momentum of the supercritical profile. Where:

AygAQM +=

2

Where: Q = Flow rate A = Cross-sectional area of flow Y = Distance from the water surface to the centroid of A The location of the jump is the point along the line when M1 = M2 and is reported as the distance from the downstream end of the line. The length of the jump however, is difficult to determine, especially in circular sections. There have been many experimental investigations which have yielded results which are contradictory. Many have generalized that the jump length is somewhere between 4 and 6 times the Sequent depth. Hydraflow Storm Sewers Extension assumes 5.


145

Hydraflow Storm Sewers Extension automatically computes supercritical flow profiles with hydraulic jumps. The dotted line shown is the Energy Grade Line.

Inlet Control Besides the Slope term in Manning’s equation, inlet and outlet control is the most misunderstood concept in storm sewer hydraulics. So just what is inlet control? Inlet control occurs when it is harder for the flow to get through the entrance of the pipe than the remainder of the pipe barrel. The only factors that matter during inlet control are the cross-sectional area of the pipe and the inlet geometry. That’s it. The roughness coefficient, pipe length, slope are not important. On the other hand, outlet control occurs when it is harder for the flow to get through the length of the pipe than it is to get into the pipe to start with. The solution is to compute the HGL assuming both exist, and then selecting the larger of the two. Hydraflow Storm Sewers Extension optionally checks HGL calculations for inlet control on all junctions except for “No Junction” types. One of the calculation procedures is derived from HDS-5 Hydraulic design of Highway Culverts. The other is the standard orifice equation. If the computed HGL for inlet control is greater than the computed HGL (outlet control), then the HGL Junct is set equal to the inlet control value. When inlet control is used, the minor loss (junction loss) is not computed.


146

The standard orifice equation used is:

ghCoAQ 2=

Where: Co = Orifice coefficient = 0.62 A = Cross-sectional area of flow in sqft (sqm) h = Headwater depth to the center of A in ft (m) Note: This is the default equation used when working in SI units.

Flow Under Inlet Control When choosing the HDS-5 method, the following inlet control equation is used:

( )⎥⎥⎦

⎤

⎢⎢⎣

⎡−+×= SY

DAQ

cDHdi 5.2

Where: Hdi = Headwater depth above invert. D = Line Rise, ft c = 0.0398 (Coeff. for square edged circular section) Q = Flow rate, cfs A = Full cross-sectional area of pipe, sqft Y = Coeff. 0.67 S = Line slope, ft/ft

Invert

Crown

HGDN

HG Junct

Grade Rim Elev

JunctionSpan Rise

Inlet Control


147

______________________________________________________________ Note This equation applies only when Q/AD0.5 is greater than or equal to 4.0. Remember, inlet control is only considered when the “Check for Inlet Control” option is set on in the Design Codes. Otherwise inlet control is not evaluated. ______________________________________________________________

The Rational Method

Hydraflow Storm Sewers Extension computes peak flows using the Rational Method. This method is expressed by the formula:

KrCiAQ =

Where: Q = discharge in cfs (cms) Kr = 1 (.0277) C = runoff coefficient. See Appendix. i = rainfall intensity in in/hr (cm/hr) A = drainage area in ac (ha) The rainfall intensity is computed by the formula: FHA Equation

( )DTc EBI

+=

Where: B, D and E are constants Tc = time of concentration in minutes subject to the Min. Tc set in the Design Codes. The constants are pre-computed by Hydraflow Storm Sewers Extension and are based on geographic location. The time of concentration is the time required for water to flow from the most remote point of the drainage area to the point of the system in question. Hydraflow Storm Sewers Extension computes Tc by choosing the greatest of the following:


148

1. The time of concentration of the upstream line plus the time of flow through the line from the upstream run. 2. The time of concentration as above for any other connecting line(s). 3. The inlet time of the line under consideration. For the most upstream run, the time of concentration is the inlet time. For all succeeding lines, the time of concentration is computed as the largest value of the three items above. When computing flows for downstream lines, Hydraflow Storm Sewers Extension uses a total CxA, that is, CA for the line in question plus CA for the next upstream line plus CA for the next upstream line and so on. Third Degree Polynomial Equation Hydraflow Storm Sewers Extension has the option of creating IDF curves using a third degree polynomial equation as follows:

DxCxBxAI 32 +++= Where: I = rainfall intensity in in/hr (cm/hr). X = Ln(time duration in minutes). A = coefficient. B = coefficient. C = coefficient. D = coefficient. Appropriate values for X are 8 to 180 minutes subject to the Min. Tc set in the Design Codes.

Rainfall IDF Curves Hydraflow Storm Sewers Extension builds its rainfall IDF curves from user supplied data. In the case of using map data (FHA Method), Hydraflow Storm Sewers Extension computes rainfall intensity values based on the methods presented in FHWA Hydraulic Engineering Circular No. 12, Drainage of Highway Pavements, more commonly known as HEC-12. The calculation methods for the Eastern and Central United States are different from the Western region.


149

Important: This method does not produce 1- or 3-year return periods.

Eastern and Central United States Precipitation values for the 2-year and 100-year frequencies of 5, 15, and 60 minute durations are required for input. Hydraflow Storm Sewers Extension uses these values and the following equations to estimate values for 10 and 30 minute durations. 10 min value = 0.59 x (15 min) + 0.41 x (5 min) 30 min value = 0.49 x (60 min) + 0.51 x (15 min) The following equations are used to compute values for return periods intermediate to the 2 and 100 year frequencies. 5-yr = 0.278 x (100-yr) + 0.674 x (2-yr) 10-yr = 0.449 x (100-yr) + 0.496 x (2-yr) 25-yr = 0.669 x (100-yr) + 0.293 x (2-yr) 50-yr = 0.835 x (100-yr) + 0.146 x (2-yr) Once the rainfall volumes for the 2-yr through 100-yr frequencies of 5, 10, 15, 30 and 60 minute durations have been computed, Hydraflow Storm Sewers Extension converts them to intensity values in in/hr.

Western States Precipitation values required for input are the 24-hr and 6-hr durations for the 2-yr and 100-yr frequencies. Hydraflow Storm Sewers Extension uses these values and the following equations to compute 60-min duration values. Y2 = 0.218 + 0.709 x [X1 (X1/X2)] Y100 = 1.897 + 0.439 x [X3 (X3/X4)] - 0.008 x Z Where: Y2 = 2-yr, 60-min value Y100 = 100-yr, 60-min value X1 = 2-yr, 6-hr value X2 = 2-yr, 24-hr value X3 = 100-yr, 6-hr value X4 = 100-yr, 24-hr value


150

Z = point elevation in hundreds of feet Next, Hydraflow Storm Sewers Extension uses a built-in nomograph to compute precipitation amounts for return periods intermediate to the 2-yr and 100-yr frequencies. Built-in ratios are then applied to convert the 60-min volumes to 5, 10, 15 and 30-min volumes. See HEC-12. The rainfall volumes are then converted to intensities in in/hr.

Equation Coefficients Hydraflow Storm Sewers Extension computes rainfall intensity for any time duration or Tc, using the FHA equation described above.

( )DTc EBI

+=

The coefficients B, D and E are computed by Hydraflow Storm Sewers Extension using a log-log interpolation of the rainfall intensity values. This, in effect, plots to an almost straight line. Hydraflow Storm Sewers Extension then uses a trial and error process of determining a constant, D, which when added to corresponding Tc's, allows the line to plot straight. The coefficient B, is the ordinate at t = 1. The coefficient E, is the slope of the plotted line. This procedure is repeated for each frequency.

Using Existing IDF Curves to Develop Coefficients You can derive your own equation coefficients in case the computed ones do not exactly match those that you are accustomed to. Simply reverse the procedure described above. Plot your existing rainfall intensity - duration curve(s) on Log-Log paper. The values B, D and E can then be found and directly entered into Hydraflow Storm Sewers Extension. Normally, the initial plotted line is not straight. If it does plot straight, D = 0. Otherwise, select a constant, D, say 5. Add this to each of the Tc ordinates. Re-plot the line. If it is then straight, D = 5. If it is not straight, try different constants until the line is straight. B is then the intensity at Tc = 1 while E is the slope of the plotted IDF line. Simply edit the IDF curve coefficients to match the ones derived and save.


151

Inlets One of the best features of Hydraflow Storm Sewers Extension is its ability to design and analyze a system of curb, grate, combination, drop curb, drop grate, and known capacity inlets. Inlets are located at the upstream end of a line and can be in a sag or on a longitudinal slope and can be of any size. The purpose of this analysis is to determine the amount of flow a particular inlet can capture, the ponding depth, inlet and gutter spread widths, the amount of flow that is bypassed, and what affect it has, to downstream inlets. Hydraflow Storm Sewers Extension has design features that will size inlets to capture 100% of the flow. To simplify this process, Hydraflow Storm Sewers Extension assumes that all inlets have common n-values. These values are specified in the "Design Codes". Gutters, however, contain unique n-values values for each line. Hydraflow Storm Sewers Extension follows the basic methodology of FHWA HEC-22 for inlet interception capacity calculations. Clogging factors are not used in this program. It is suggested, if needed, that you adjust your inlet lengths to account for clogging factors.

Plan View

Q catchment Hydraflow Storm Sewers Extension uses a separate and slightly different analysis for determining Qs for inlets than that for the overall line network. The Qs for inlets are computed using the Rational formula, Q = CIA. But I is the intensity based on the individual catchment's inlet time, not the cumulative Tc, and the C x A term is the individual catchment's drainage area and corresponding runoff coefficient. This Rational method Q is labeled as "Incr


152

Q" and “Q=CiA” in the reports. Note that "Known Q's" will be added to overland flows. Carryover and Bypassed Q's Q's for individual inlets are developed from two components. The first is that from the catchment's drainage area or runoff. The second component is from excess flows, or noncaptured flows. Noncaptured flow is called "carryover" when it is coming from upstream inlets. It is called "bypassed" when an inlet cannot capture 100% and sends a portion of the total flow offsite or to another specified target inlet. Carryover and bypass flows are both noncaptured flows. To an inlet, carryover is an incoming flow and bypassed is an outgoing flow. These flows are labeled as "Q carryover " and "Q bypassed" on the reports. Note that lines with a manhole or no inlet will bypass all carryover flows to its downstream line.

Inlets in Sags An inlet in a sag, or sump, has no longitudinal slope, i.e., the gutter slope equals zero. In addition, inlets in sags capture 100% of the flow and thus no bypass flow. Note that the Drop Curb inlet must be in a sag.

Curb Inlets in Sags

Curb inlets operate as weirs to depths equal to the curb opening height and as orifices at depths greater than 1.4 times the throat height. At depths in between, flow is in a transition stage. Depressed Curb Opening The equation used for the interception capacity of the inlet operating as a weir is:


153

( )dWLCwQ 5.18.1+=

Where: Cw = 2.3 (1.25) L = Length of curb opening in ft (m) W = Gutter width in ft (m) d = Depth at the face of curb measured from the cross slope, Sx, in ft (m) Note: If L > 12 feet then the equation for non-depressed inlets is used, per HEC-22.

Without Depression The equation used for the interception capacity of the inlet operating as a weir is:

5.1CwLdQ =

Where: Cw = 3.0 (1.60) L = Length of curb opening in ft (m) d = Depth at the face of curb measured from the cross slope, Sx, in ft (m) The equation used for the interception capacity of the curb inlet (depressed and non-depressed) operating as an orifice is:

Throat Height

Local Depression, a

Sx

Gutter Width

Spread

Sw

d


154

( )ogdCohLQ 2=

Where: Co = 0.67 h = Total height of curb opening in ft (m) L = Length of curb opening in ft (m) g = 32.2 (9.8) gravity do = Depth measured to the center of the inlet opening in ft (m) It should be noted that the inlet depths reported are measured from the lip of the curb opening, i.e., Depth = Do + (h / 2) where h is the total opening. Inclined Depths = Do + (h / 2)Sin(45o). In transition flow, Hydraflow Storm Sewers Extension uses both equations and selects the smallest Q. If the inlet length has been set to 0 by you, Hydraflow Storm Sewers Extension automatically computes it by using the above weir equations assuming the depth to be equal to the total curb opening and solving for L.

Grate Inlets in Sags Grate inlets in sags operate as weirs to a certain depth dependent on their bar configuration and operate as orifices at greater depths. Hydraflow Storm Sewers Extension uses the procedure as described in HEC No. 22. Hydraflow Storm Sewers Extension uses both orifice and weir equations at a given depth. The equation that produces the lowest discharge is used. The standard orifice equation used is:

gdCoAgQ 2=

Where: Co = 0.67 Ag = Clear opening area in sqft (sqm) g = 32.16 (9.8) gravity d = Depth of water over the grate in ft (m) The weir equation used is:

dCwPQ 5.1=


155

Where: Cw = 3.0 (1.66) P = Perimeter of the grate in ft (m) disregarding side against curb d = Depth of water over the grate in ft (m) If the grate area, A, has been set to 0 by you, Hydraflow Storm Sewers Extension automatically computes it using the orifice equation and by assuming d = "Grate Design Depth" as entered in the "Design Codes". If the perimeter, P, has been set to 0 by you, Hydraflow Storm Sewers Extension sets it by assuming d = "Grate Design Depth" as specified in the "Design Codes" and solving for P in the weir equation. It is believed that when the depth of water over the grate = 0.3 ft (.09 m), the inlet begins a transition to acting as an orifice.

Combination Inlets in Sags The interception capacity of combination inlets in sags is equal to that of the grate alone in weir flow. In orifice flow the capacity is equal to the capacity of the grate plus the capacity of the curb opening. Ref. HEC-22. Hydraflow Storm Sewers Extension essentially uses the procedure described above for grate inlets in sag. However, when the depth at the curb is such that orifice conditions exist for the grate, Hydraflow Storm Sewers Extension uses both procedures, grate and curb inlets in sags, and adds their capacities to arrive at the total capacity. Note that both weir and orifice equations are used for the curb inlet analysis. In other words, the grate could be in orifice flow while the curb opening is in weir flow. As with the single grate inlet, if the grate area, A, on the combination inlet has been set to 0 by you, Hydraflow Storm Sewers Extension automatically computes it using the orifice equation and by assuming d = "Grate Design Depth" as entered in the "Design Codes" and solving for Ag. If the perimeter, P, has been set to 0 by you, Hydraflow Storm Sewers Extension sets it by assuming d = "Grate Design Depth" as entered in the "Design Codes" and solving for P in the weir equation. There is not a design option for the curb opening length on combination inlets. Hydraflow Storm Sewers Extension by default sets it equal to the grate length if found to be 0.


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Inlets on Grade An inlet on grade has a positive longitudinal gutter slope. Hydraflow Storm Sewers Extension uses methods presented by HEC-22. Please note that for depressed inlets, the quantity of flow reaching the inlet is dependent on the upstream gutter section geometry and not the depressed section.

Curb Inlets on Grade The interception capacity for curb inlets is computed using the following equation. The equation also applies to slotted inlets.

( )nSe

SQKL LTT1 6.0

3.042.0=

Where: LT = Curb opening length for 100% capture in ft (m) KT = 0.6 (0.817) Q = Gutter flow in cfs (cms) SL = Gutter slope, longitudinal in ft/ft (m/m) n = Manning's n-value Se = Equivalent cross slope

oWX ESSSe '+= Where: Sx = Cross slope of pavement in ft/ft (m/m) S'w = Depression in ft (m) / gutter width in ft (m) or, for non-depressed inlets, cross slope Sw - cross slope Sx E0 = Ratio of flow in the gutter section to total gutter flow When the inlet length has been set to 0 (design) by you, Hydraflow Storm Sewers Extension automatically sets the inlet length equal to LT. If the specified inlet length is larger than LT, it will capture 100% of the flow and "Q captured will equal Q. If the specified inlet length is less than the computed LT, then Q captured is computed as follows:

FT EQQcaptured ×= Where: QT = Q catchment + Q carryover EF = 1 - (1 - L/LT)1.8 = Efficiency


157

Q bypassed equals QT - Q captured

Grate Inlets on Grade The interception capacity of grate inlets on grade is computed using the following equations per HEC-22:

( )osof ERERE −+= 1

Where: E = Efficiency of the grate Rf = Ratio of intercepted frontal flow to total gutter flow E0 = Ratio of frontal flow to total gutter flow Rs = Side flow interception efficiency Note: The Rf term in the above equation is dependent on the specific grate properties illustrated in HEC-22 and most likely will not match every situation. In that light, Hydraflow Storm Sewers Extension assumes Rf = 1. This assumes all frontal flow will be intercepted without any loss of flow due to splash-over effects. All of the grate on grade examples given in HEC-22 compute an Rf = 1.

⎥⎦

⎤⎢⎣

⎡⎟⎟⎠

⎞⎜⎜⎝

⎛+

=

LSVKc

Rs

X3.2

8.1

1

1

Where: Kc = 0.15 (0.0828) V = Velocity of flow in the gutter in ft/s (m/s) L = Grate length in ft (m) The amount of intercepted flow for grates on grade = E x Q. Of course, any non-intercepted flow is bypassed. If the grate length has been set to 0 for design, Hydraflow Storm Sewers Extension will use the following weir equation:

dPCQ W5.1=

Where: Cw = 3.0 (1.66) P = Perimeter of the grate in ft (m) disregarding side against curb


158

d = Depth of water over the grate in ft (m) It solves for P and then sets the grate length, L, equal to P – 2 x (grate width). Note that this design does not guarantee 100% capture. Combination Inlets on Grade The interception capacity of combination inlets on grade is essentially equal to that of the grate alone. Hydraflow Storm Sewers Extension computes this capacity by neglecting the curb opening and using the methods described above.

Sweeper Inlets When the curb opening length is longer than the grate length, Hydraflow Storm Sewers Extension assumes the open curb portion to be located upstream of the grate, often called a "sweeper" inlet. The sweeper inlet has an interception capacity equal to the sum of the curb opening upstream of the grate plus the grate capacity. The grate capacity in this case is reduced by the interception by the upstream cub opening.

Gutter Spread Hydraflow Storm Sewers Extension uses the following modified Manning equation to compute the depth of flow in the gutter:

( )SKcZ

QnD

375.0

=

Where: D = Depth of flow in gutter in ft (m) Q = Flow in gutter in cfs (cms) Z = Reciprocal of the cross slope S = Longitudinal gutter slope Kc = 0.56 (0.376)


159

For compound cross slopes, Hydraflow Storm Sewers Extension uses a trial and error procedure and computes D in the gutter, (Sw) and (Sx) sections separately. From this depth, and cross-section geometry, Hydraflow Storm Sewers Extension computes the gutter spread. This depth and spread is labeled "Gutter Depth" and "Gutter Spread" respectively in the reports.

Inlet Spread

Using the above equations for the variety of inlet types and conditions it computes the final inlet depth as the total depth at the inlet, not just d, for example. The inlet spread is then computed accordingly using basic geometry. This depth and spread is labeled as "Inlet Depth" and "Inlet Spread" respectively in the reports.

Design Options Hydraflow Storm Sewers Extension offers various design options regardless of which calculation option you use "Analysis & Design", "EMS", "Full Design"

Sx

Gutter Width

Inlet Spread

Inlet Depth

Sx

Gutter Width

Gutter Spread

Sw


160

or "Capacity Only". They are; 1) designing pipe sizes; 2) setting invert elevations and 3) designing both simultaneously. When designing, Hydraflow Storm Sewers Extension uses the following form of Manning's equation.

⎟⎠⎞⎜

⎝⎛

=S

KdnQD

375.0

Where: D = Pipe diameter in ft (m) n = Manning's n-value Q = Line discharge in cfs (cms) or velocity x pipe area S = Slope of the invert in ft/ft (m/m) Kd = 2.16 (3.20) This procedure assumes that the pipe is flowing full and that the slope of the invert is equal to the slope of the energy grade line. Important! The S, or slope term in Manning's equation, in its traditional use, is the slope of the energy grade line. Not the slope of the invert. This confuses many engineers. In real conditions, the slope of the invert seldom equals that of the energy grade line. Case 1: Inverts given, pipe size set to 0 (Design). Hydraflow Storm Sewers Extension will automatically compute a pipe size by:

cityDesignVeloQArea =

It then selects an available pipe size whose area matches “Area”. It only chooses certain sizes that have been predetermined. That is, 12 to 36 inches in 3-inch increments and 42 to 102 inches in 6-inch increments, or their metric equivalents. See "Using Metric Units" in the previous chapter. When a specific pipe size is not available, Hydraflow Storm Sewers Extension will select the next smaller size. For example, if the theoretical size is 31.5 inches, Hydraflow Storm Sewers Extension will round down and select the 30-inch.


161

Case 2: Pipe size given, invert set to 0. When designing for invert elevations, Hydraflow Storm Sewers Extension simply uses the above equation, setting the velocity equal to the "Design Velocity" as set in the "Design Codes", and solves for S. It then sets the invert elevations accordingly. If the resulting slope, S, is less than the "Minimum Slope", then S is reset to the minimum slope and a new pipe size will be selected at the new slope, using Manning's equation. If Follow Ground Surface has been selected as a calculation option, then the slope is set first to match grade. If the slope exceeds the Maximum Slope as set in the Codes, then it is reset to the Maximum Slope. Case 3: Inverts set to 0, Pipe size set to 0. Hydraflow Storm Sewers Extension, computes the required full pipe area by:

cityDesignVeloQArea =

It then selects an available pipe size whose area matches “Area”. With the chosen pipe size, it sets the inverts using the procedure in Case 2. Note that the final velocity will not always be equal to the "Design Velocity". This is due to the affects of the downstream HGL after the design is complete. If you were, however, to re-compute results using the "Capacity Only" option, the final velocity will be equal to the "Design Velocity".

Enhanced Modeling System (EMS)TM

The Enhanced Modeling SystemTM is designed to eliminate conflicts between the time of concentration and the final hydraulic grade line. Traditionally, storm sewers are designed to flow full. This is acceptable because the pipes are sized, after the fact, to accommodate the design flows and velocities. Thus there are no conflicting numbers, i.e., Tc's match the Q's. When analyzing existing systems, however, the actual velocity is not known until the hydraulic grade line (HGL) is computed. The computed Q's and HGL are based on assumed pipe velocities. When the real velocity is different from the assumed velocity, the computed Tc is incorrect and thus the computed Q and resulting HGL are incorrect. The


162

Enhanced Modeling SystemTM solves this problem by re-computing the hydraulic grade line (HGL) based on actual flow rates and actual Tc's. To do this Hydraflow Storm Sewers Extension must compute three system iterations so that the computed Tc's match those that were assumed with reasonable accuracy. Hydraflow Storm Sewers Extension first computes the HGL using Tc's based on the design velocity. It then computes the system a second time using Tc's based on actual velocities. These new velocities are still incorrect because they are based on the original HGL calculation, but they are more accurate than those used on the first trial. As one would expect, several system iterations would cause the Q's, Tc's and resulting HGL to converge to correct values. After extensive testing, it has been concluded that three iterations is the most practical balance between accuracy and time required to produce the results. The EMSTM should be always be used on existing systems when the hydraulic analysis is critical and maximum accuracy is of importance.

A-1

Appendix A Runoff Coefficients (C)

Description of Area Coefficient Business: Central business 0.70 - 0.95 District and local 0.50 - 0.70 Residential: Single family 0.35 - 0.45 Multi-units 0.40 - 0.75 1/2 acre lots or larger 0.25 - 0.40 Industrial: Light 0.50 - 0.80 Heavy 0.60 - 0.90 Parks, cemeteries 0.10 - 0.25 Playgrounds 0.20 - 0.35 Railroad yards 0.20 - 0.40 Unimproved 0.10 - 0.30 Asphaltic 0.70 - 0.95 Concrete 0.80 - 0.95 Roofs 0.75 - 0.95

A-2

Manning’s n-Values Surface Manning's "n" Reinforced concrete pipe 0.013 Reinforced concrete box 0.013 Vitrified clay pipe 0.013 Coated cast iron 0.011 Uncoated cast iron 0.012 Wrought-iron, black 0.013 Wrought-iron, galvanized 0.014 Smooth welded pipe 0.011 Riveted and spiral steel 0.015 Corrugated metal pipe 0.023 Corrugated aluminum pipe 0.023 Corrugated metal multi-plate 0.035 Polyvinyl chloride (PVC) 0.010

Index Accumulate Known Q's 39

Adding lines 41

alignment 8, 36, 93, 127

Analysis and Design82, 84, 96

arch pipes 52

background image125, 126, 130,

132, 133

Bypass flows 56

Bypass Target 63

Calculation options 83

Calculation Report 103

Capacity Only82, 83, 85, 96, 103,

160, 161

Captured flows 56

Carryover flows 56

Colors 71

composite coefficient 48

cost 7, 24, 80, 81, 82, 113

Cost Report 104

Critical depth 38, 141

Cross Slope, Sw 65, 109

Cross Slope, Sx 65, 109, 113

curb opening inlet 57

Custom Report 105, 107, 136

Deflection Angle 47, 109

delete lines 76

Design Codes 33

Design Velocity34, 102, 103, 161

DOT Report 101

drainage area39, 47, 48, 114, 115,

147, 151, 152

drop curb inlets 61, 109

Drop grate inlets 61

dxf file 124, 125, 127, 128

Enhanced Modeling System82,

84, 161

Exporting the Results Grid 99

FL DOT Report 102

freeze a column 97

Full Design35, 82, 85, 88, 96, 159

Generic inlet 59

Global Editing 75

Grate Design Depth 37, 64, 155

Grate Width & Length 64

gutter cross slopes 61

Gutter Depth 111, 159

Gutter Spread102, 111, 158, 159

Gutter Width 65

Gutters 61

HEC-2255, 59, 61, 151, 153, 155,

156, 157

Help and Documentation 1

hydraulic grade line 140

hydraulic jump 144

IDF curves 25

inlet control 109, 145, 146

Inlet Depth 112, 159

Inlet Design Report 102

Inlet Length 63

Inlet Spread 102, 112, 159

inlet time 39, 48, 148, 151

inlet types 7, 55

Inserting Junctions 78

Inserting Lines 76

interception capacity calculations

151

junction loss40, 52, 53, 100, 143,

145

junction loss coefficient 52

junction loss coefficients40, 143

Known Q39, 47, 83, 102, 113, 152

Labels 68

LandXML file130, 131, 132, 135

Line Length 46, 47, 113, 114

Line Numbering 5

local depression7, 61, 63, 64, 65

longitudinal slope 65, 151, 152

Maximum Pipe Size 34

metric units 28, 137

Minimum Cover 35

Minimum Pipe Size 34, 36

Minimum Slope 34, 161

Minimum Starting Depth38, 140,

141

momentum 144

Move System 72

Open Channel Flow 50

Open headwalls 61

Opening Area 64

Outfall Coordinate 72

pipe quantities 80

plot31, 32, 96, 98, 117, 118, 120,

122, 150

printing 116

profile 119

Quick Start Tutorial 8

Rational Method 7, 8, 9, 25, 39,

147

Results 96

return period 27, 83

runoff coefficients 37, 102, 108

save 137

scale42, 70, 71, 77, 91, 118, 119,

121, 123

Selecting a range of lines 98

Shallow Concentrated Flow50

Sheet flow 49

Size Options 35

spread widths 62, 102, 151

Standard Step method 139

starting HGL 140, 141

Storm2003.ini 24, 82, 136

supercritical flow 143

sweeper inlet 59, 158

System Requirements 1

tailwater 86, 87

Third Degree Polynomial Equation 148

Throat Height 63, 64

TR-55 worksheet 49

Undo 42, 43, 67, 73, 76, 77, 90

Use inlet captured flows in system

39

Use Interactive Feature 88

User-Defined Stations 54

Variables List 108

Zoom42, 70, 71, 77, 91, 118, 119

storm sewers user guide

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