survcadd hydrology module - carlson softwarefiles.carlsonsw.com/mirror/manuals/old/hydro.pdf ·...

SurvCADDHydrology Module

2 Hydrology Module - DTM Commands

Slope At Points

FunctionThis command labels the slope percent at user picked points or at the grid interval. The slope iscomputed from the surface model defined by a grid file which is created by the Make 3D Grid Fileroutine. As the crosshairs are moved across the grid, the slope at the current position is displayedin the bottom of the screen menu. In addition to labeling the slope value at the user specified points,an arrow is drawn in the uphill direction. The point of the arrow is drawn at the location of thecalculated slope. The number of decimal places used to label the slope value is set by the decimalplaces in the AutoCad UNITS command. The SurvCADD d0,d1,d2, and d3 keyboard marcos canalso be used to set the AutoCad decimal places.

Overview

The Hydrology Module consists of several routines that work together in sequence. This manualonly explains the operation of the commands and not hydrology concepts. For example, you willneed to know the storm type and soil type for your area. Some routines are based on the TR-55programs and the TR-55 manual, Urban Hydrology for Small Watersheds, may be useful. TheHydrology Module also links to TR-20, SEDCAD and HEC-2. The SEDCAD links are with capacityfiles for pond design and by drawing SEDCAD hydrographs. SEDCAD, by Civil Software Design,has become a standard in the mining industry for the computation of flows and sedimentation. HEC-2 is a computer program prepared by the Corps of Engineers to compute water surface profiles instream and river channels.

D.T.M. Commands

The pull-down menu for the Digital Terrain Model com-mands of the Hydrology module is shown below. Most ofthese commands are also in the DTM-Contour module.Only the Slope At Points command is unique to this menu.The other commands are described in the DTM section ofthe DTM-Contour module manual. These DTM commandsare included here because the surface models defined bygrid files (.grd) are used by hydrology commands such aswatershed modeling.

Hydrology Module - DTM Commands Page 7-3

PromptsEnter the slope label layer <SLOPE>: Press Enter. The text output of this command will be drawnin this layer.Enter the slope label text size <4.0>: Press Enter. This is the size for the output text. The defaultis the horizontal scale multiplied by the text size scaler from Drawing Setup.Slope label format (Ratio/Degree/<Percent>): Press EnterGrid File Selection dialog boxChoose the grid file that models the surface.Reading Row 51>Extrapolate grid to full grid size (Yes/<No>)? Yes. If the limits of the surface data doesn'tcover the entire grid area, then the values for the grid cells beyond the data limit must beextrapolated in order to compute slopes in that area. This prompt only appears if there are gridcells without values.Calculate slopes at pick points or grid interval (<Pick>/Grid)? Press EnterEnter or pick point (Enter to End): pick a point. As the crosshairs are moved, the slope at the currentposition is displayed at the bottom of the screen menu.Enter or pick point (Enter to End): Press Enter to exit the routine


Draw grid file and Slope At Point labels using grid interval on same area as first example.

Pull-Down Menu Location: DTM in the Hydrology module

Prerequisite: Use Make 3D Grid File to create a grid file that models the surface.

Keyboard Command: ptslope

File Names: \lsp\cntr_grd.arx

Hydrology Module - DTM Commands Page 7-5

Universal Soil Loss

FunctionThis command calculates the volume of sediment that can be expected from a watershed by soilerosion due to precipitation. It allows the user to specify multiple watershed areas, each with itsown set of geometric and hydrological parameters. The Universal Soil Loss Equation (USLE)is used in calculating the soil loss. For each area, the area, slope and length can be manuallyentered by the user or it can be calculated by the program directly. For direct calculation of thegeometric properties of the area, the user must have a grid file that models the surface. This canbe created using the Make 3D Grid File command. In addition, the area must be defined by closedpolylines for inclusion perimeter. Exclusion perimeters are optional for excluding areas fromcalculations.

The program starts with the dialog below, where the user can add as many areas as needed toinclude in the USL calculation. Each area added is shown in the listbox with all its parameterslisted. To add a new area, click the "Add" button. To edit the parameters of an existing area,highlight that item and click the "Edit" button. To remove an existing area, highlight it and click"Remove".


The "Edit" or "Add"button brings up thedialog box shownhere, where the vari-ous parameters of thearea can be specifiedor edited. The"Landuse" is just anidentifier for the areaand has no further sig-nificance. SoilErodability, K (tons/acre) is a property ofthe soil, which deter-mines the amount ofsediment resultingfrom a precipitationevent in an area. Therainfall factor, R, is adimensionless factorthat accounts for therelationship betweenerosive forces of fall-ing rain and runoff.The Cover factor, C,is a dimensionlessfactor that relates the effectiveness of vegetal cover in reducing erosion. The Topographicalfactor, Ls, is a dimensionless length slope factor that accounts for variations in length and slopein the area. The (Conservation) Practice factor, P, is a dimensionless factor to determine howlanduse effects its erodability.

If the area of the watershed is known and is entered manually, then the length and slope of thearea have to be entered manually as well and the Ls factor will be calculated from these geometricproperties. The area can also be calculated directly if the boundary is defined as a closed polylineand the grid file that models the surface is also made. The user clicks the button "Select area" andthe program asks the user to select the grid file as well as the closed polyline representing thearea. Then, the Ls factor and the slope are calculated by the program and displayed (the "length"is not needed in this case). After filling in all values, click on "Calculate USL" to calculate thesoil loss rate per unit area for the area selected. The user can change the parameters correspond-ing to this are and recalculate, if needed. Click "OK" to return to the main dialog box. The areashould now appear in this dialog box if the parameters as specified.

After all required areas are input, the sediment volume can be calculated by clicking the"Calculate" button on the main dialog. This brings up the USLE Calculation dialog box as shownhere. Specify the Delivery ratio, which determines what portion of the gross erosion is actually

Hydrology Module - DTM Commands -7

left for deposition at the final destination,accounting for losses during sedimenttransport. Also, specify the Time periodfor which deposition has occurred. Specifythe Density of the sediment, so as to beable to determine the volume of the de-posit from its mass in tons. Also, specifythe amount of Rainfall (inches or cm) forwhich runoff volume has to be calculated.The program then calculates the Runoffvolume based on the total area and theamount of rainfall. It also calculates the sediment volume, using the Universal Soil Loss Equation(USLE) and adds it to the sediment volume and reports it as the total pond volume. A report of theform shown below is generated. This report also gives a detailed account of the calculationsperformed. For further information about the estimation of the various parameters used in thisprogram or about the USLE, please refer to "Applied Hydrology and Sedimentology for DisturbedAreas" (1981), Barfield, B.J., Warner, R.C. and Haan, C.T., Oklahoma Technical Press.

Pull-Down Menu Location: DTM in the Hydrology module

Prerequisite: Use Make 3D Grid File to create a grid file that models the surface.

Keyboard Command: soilloss

File Names: \lsp\cntr_grd.arx, \lsp\peakflow.dcl, \lsp\soilloss.lsp

8 Hydrology Module - Watershed Commands

Watershed CommandsThe Watershed pull-down menu is shown below. These commands are arranged in the order thatthey would be applied. The first command calculates the watershed boundary. Using thewatershed area and land use types, the curve number can be calculated which leads to time ofconcentration and hydrographs. Then the peak flow can be calculated.

Hydrology Module - Watershed Commands Page 7-9

Watershed Above Point

FunctionThis command createsa closed 3D watershedpolyline of the area thatdrains through userspecified points and re-ports the horizontal andslope areas, averageslope, and longest flowpath values. This wa-tershed is calculatedfrom the surface that ismodeled by a grid fileor triangulation file.The grid file can be created by the Make 3D Grid File command and the triangulation file can becreated with the Write Triangulation File option in Triangulate & Contour in the DTM & Contourmodule. A triangulation surface model has the advantage of finding sharp break lines that a gridmight skip over such as narrow ditches. For regular surfaces such as a surface defined by existingcontour polylines, the grid surface model should be used because it is much faster. Also whenusing a grid surface model it is sometimes better to decrease the grid resolution (have fewer gridcells) because this helps avoid local minimums.

The program prompts for points on the left and right side of the downstream flow line. Thewatershed polyline will include the area of runoff lines that pass between these two points. Theleft and right sides is relative to facing up the slope.

To generate a watershed that excludes a smaller watershed within it, create both watersheds andthen use the 2D Polyline with Follow command.

PromptsEnter the watershed boundary layer <WATERSHED>: Press EnterGrid File Selection dialog boxChoose the grid file that models the surface.Reading Row 51>Extrapolate grid to full grid size (Yes/<No>)? Yes. If the limits of the surface data doesn'tcover the entire grid area, then the values for the grid cells beyond the data limit must beextrapolated in order to compute slopes in that area. This prompt only appears if there are gridcells without values.Pick bottom LEFT bank of watershed: pick a point on the left bank. Left is relative to facinguphill.Pick bottom RIGHT bank of watershed: pick a point on the right bank. Right is relative

Watershed 2 ReportProcessing GRiD file: D:/SC12/DATA/SIMO.GRDLower left grid corner : 186384.62,57529.63Upper right grid corner: 186885.68,58014.67X grid resolution: 65, Y grid resolution: 60X grid cell size: 7.71, Y grid cell size: 8.08Horizontal Area is 9868.302 sq ft, 0.227 acresSlope Area is 10934.185 sq ft, 0.251 acresAverage Slope is 25.548%Longest horizontal dist: 180.84, Longest slope dist: 180.84Vertical drop: 30.23, Avg slope: 20.39%, Max slope: 57.13%


Multiple Watershed Polylines

FunctionThis command finds all the sub-wa-tersheds on a surface modeled bytriangulation (.flt) or grid (.grd) file.The watershed boundaries are drawnas closed polylines with the option tosolid fill these areas. The programalso generates a report with the wa-tershed average slope and horizontaland slope areas. The surface is mod-eled by a triangulation file (.flt file)created by Triangulate & Contour.The program draws watersheds forall the sinks. Sinks are where an areaflows off the edge of the surface or alocal minimum on the surface. Theoptions for this routine are set in thedialog shown below. Rainfall Levelis for avoiding local minimums orpuddles. If the depth of the puddle isless than the Rainfall Level, then thewatershed will enclose this area. Oth-erwise this local minimum becomesa sink and the area that flows into itbecomes a watershed boundary.

Pull-Down Menu Location: Watershed

Prerequisite: An .flt triangulation file

Keyboard Command: waterdeli


to facing uphill.Tolerance range at through point <10.0>: Press Enter. This is the distance to offset from thepicked point.Pick bottom LEFT bank of watershed: Press Enter to end.


Prerequisite: A .grd file created by Make 3D Grid File

Keyboard Command: watershed


Watershed ReportProcessing TIN file: C:\scdev\data\simo2.fltSink #1 location X: 2476.46, Y: 8903.36, Z:161.70Horizontal Area is 73903.893 sq ft, 1.697 acresSlope Area is 76237.321 sq ft, 1.750 acresAverage Slope is 19.762%----------------------------------Sink #2 location X: 1419.61, Y: 9525.77, Z:124.02Horizontal Area is 4000.481 sq ft, 0.092 acresSlope Area is 4006.388 sq ft, 0.092 acresAverage Slope is 5.195%----------------------------------Sink #3 location X: 2658.64, Y: 9048.32, Z: 79.46Horizontal Area is 5959.110 sq ft, 0.137 acresSlope Area is 6321.574 sq ft, 0.145 acresAverage Slope is 29.898%----------------------------------Sink #4 location X: 1717.49, Y: 1548.70, Z: 86.92Horizontal Area is 953900.644 sq ft, 21.899 acresSlope Area is 980891.891 sq ft, 22.518 acresAverage Slope is 20.466%----------------------------------Sink #5 location X: 2618.02, Y: 1229.49, Z: 70.26Horizontal Area is 482639.991 sq ft, 11.080 acresSlope Area is 509441.311 sq ft, 11.695 acresAverage Slope is 28.836%


Surface contours

Solid filled watershed areas


Run Off Tracking

FunctionThis command draws 3D polylines starting at user picked points downhill until they reach a localminimum or the end of the grid. In effect it simulates the path of a rain drop. The surface ismodeled by a grid file as created by Make 3D Grid File or a triangulation file created byTriangulate & Contour. The program also reports the horizontal and slope distances, averageslope, maximum slope, and vertical drop. These values can be used for time of concentrationcalculations.

PromptsEnter the run off path layer <RUNOFF>: Press EnterGrid File Selection dialog boxChoose the grid file that models the surface.Reading Row 51>Extrapolate grid to full grid size (Yes/<No>)? Yes. If the limits of the surface data doesn'tcover the entire grid area, then the values for the grid cells beyond the data limit must beextrapolated in order to compute slopes in that area. This prompt only appears if there are gridcells without values.Pick origin of rain drop: pick a point at the top of the run off polylinePick origin of rain drop (Enter to end): Press Enter


Prerequisite: A .grd file created by Make 3D Grid File

Keyboard Command: runoff



Rainfall Frequency and Amount

FunctionThis command allows you to view rainfall maps while entering the rainfall amount to be used byother hydrology commands. First choose a storm and duration from the list. Then choose yourlocation from the state list or pick your location on the map. You can enter the rainfall amountin the box in the lower left or pick your location on the map.

Reference maps are provided for all fifty states for the different storm intervals. You can alsosetup user-defined lookup tables for up to five areas. For each area, you can specify a name andrainfall amounts for each storm interval. The first time the you select a user-defined storminterval, the rainfall amount will be blank. Enter in the rainfall amount and the next time thatinterval is selected, your entered value will be there. The user-defined values are stored in a filecalled rainmap.ini in the SurvCADD USER directory.

3D Polyline Flow Values

FunctionThis command simply reports the horizontal and slope distances, vertical drop, maximum slope,and average slope of 3D polylines. The 3D polylines may be created by the Watershed AbovePoint or Run Off Tracking commands. The reported values could be applied to the Time ofConcentration routine.

PromptsSelect 3D polyline flow line: pick a 3D polylineHoriz dist: 217.96, Slope dist: 219.08, Vertical drop: 19.22Average slope: 8.82%, Maximum slope: 17.68%Select 3D polyline flow line or Enter to end: Press Enter


Prerequisite: 3D polyline

Keyboard Command: flowvals



Sub-Watersheds By Land Use

FunctionThis command divides land-use polylines into closed polylines within a watershed polyline. Theclosed land-use polylines inside the watershed can then be used to determine the area of eachland-use for the watershed. The Curve Numbers & Runoff command has an option to selectclosed polylines for determining the weighted average curve number from the polyline areas.

PromptsSelect closed polyline of watershed: pick the polylineSelect land-use closed polylines.Select objects: pick the polylines


Prerequisite: Closed polylines for the watershed and land-use areas.

Keyboard Command: landarea

File Names: \lsp\mineutil.arx


Prerequisite: none

Keyboard Command: rainmap

File Names: \lsp\rainmap.lsp & \sup\slides\*.sld


Curve Numbers & Runoff

FunctionThis command calculates the either the weighted curve number or C-factor and the runoff. Thecurve number is used by routines based on the TR-55 program. The C-factor is used by therational method for Peak Flow calculation. The weighted curve number is a weighted average ofthe curve numbers for each subarea of the watershed. The weights are based on the areas. Thecalculated C-factor is also weighted by area. This routine has spaces for both curve numbers andC-factors but you only need to fill in one type. The Description and Soil Type fields are used inthe report.

To select the subareas from AutoCad, click on the Select Areas from Screen button. Then selectall the subarea closed polylines. These polylines can be generated by the Sub-Watershed by LandUse command. After selecting the areas, the program cycles through each area by highlightingthe polyline and prompting for the curve number. Either enter the curve number or type T toselect a curve number from the table. The areas and curve numbers selected in this procedureoverwrite any previous entries.

When all the land-use curve numbers and areas are entered, click on the Calc CN button tocalculate the weighted curve number. This curve number can then be used in the Time ofConcentration and Peak Flow commands.

To calculate the runoff given the weighted curve number, enter the rainfall for the storm inquestion and then click on the Calc Runoff button. The Runoff Volume equals the Runoff Q timesthe total area.

Runoff Curve Number and RunoffProject: Park By: TW Date: 01/30/99Location: Checked: Date:Present

1. Runoff curve number (Cn)Cover description CN Soil Type AreaOpen Space 79 A 28.816 AcresSandy 86 B 31.231 AcresWoods, good 70 A 15.476 AcresCN (weighted): 80

2. RunoffFrequency .............. : 100 yrRainfall, P (24-hour) .. : 4.80 inRunoff, Q .............. : 2.72 inRunoff Volume .......... : 17.14 Acre-Ft


Table to select CNfrom.


Prerequisite: None.

Keyboard Command: curveno

File Names: \lsp\cntr_grd.arx & \lsp\hydro.dcl


Time of Concentration

FunctionThis command calculates the time of concen-tration (Tc) by either the TR-55 method, Ratio-nal method or the SCS method from A Methodof Estimating Volume and Rate of Runoff inSmall Watersheds. The Tc value is used in theHydrograph and Peak Flow commands. Time ofconcentration is the time required for water toflow from the most distant point in the water-shed to the measurement point.

The rational method calculates based on thecurve factor, length of flow and average slope.These values are set in the dialog shown. Theformula is: Tc = (1.8 * (1.1 - cf) * sqrt(length)) / (slope ^0.33)

The SCS method calculates based on the curvenumber, length of flow, and average slope. Thecurve number defaults to the weighted curvenumber from the Curve Numbers & Runoffroutine. When the three inputs are entered,click on Calculate to compute the Tc. ChooseSelect Flow Line from Screen to use a 3Dpolyline in the drawing. This sets the length offlow and average land slope. A 3D polyline that models the flow can be created with theWatershed Above Point or Run Off Tracking commands. While reading in the 3D polyline, theTc is calculated by adding the Tc's for each segment of the polyline. This yields a different andmore accurate Tc than using the average slope with the Calculate button.

The TR-55 method divides the type of flow into sheet, shallow concentrated and channel flow.The time of concentration is the sum of the times for the three types. The manning's n for thesheet and channel flow can be chosen from a table by clicking the Select from Table button.


Prerequisite: None.

Keyboard Command: flowtc

File Names: \lsp\cntr_grd.arx & \lsp\hydro.dcl

Dialog for Tc by SCS method

Rational method dialog


Dialog for Tc by TR-55 method


Time of Concentration (Tc) or Travel Time (Tt)

Project: Parking By: TW Date:Location: West Checked: Date:DevelopedTc through subarea 1

Sheet flow (Applicable to Tc only) Segment ID: AB1. Surface description .......................... : Dense Grass2. Manning’s roughness coeff. (n) ............... : 0.2403. Flow length, L (total L < 300 ft) ............ : 100.0 ft4. Two-yr 24-hr rainfall, P ..................... : 3.60 in5. Land slope, s ................................ : 0.010ft/ft6. Tt ........................................... : 0.296 hr

Shallow concentrated flow Segment ID: BC7. Surface unpaved8. Flow length, L ............................... : 1400.0 ft9. Watercourse slope, s ......................... : 0.010ft/ft10. Average velocity, V ......................... : 1.60 ft/s11. Tt .......................................... : 0.243 hr

Channel flow Segment ID: CD12. Cross sectional flow area, a ................ : 27.00 ft^213. Wetted perimeter, Pw ........................ : 28.20 ft14. Hydraulic radius, r ......................... : 0.96 ft15. Channel slope, s ............................ : 0.005ft/ft16. Manning’s roughness coeff. (n) .............. : 0.05017. Velocity, V ................................. : 2.05 ft/s18. Flow length, L .............................. : 7300.00 ft19. Tt .......................................... : 0.991 hr

20. Watershed or subarea Tc or Tt ............... : 1.530 hr

Tc by TR-55 method report


Peak Flow - Graphical Method

FunctionThis command calculates peak flow using thegraphical method from the TR-55 program.The program is run through the dialog shownbelow. The inputs in the top section default tothe values from the Curve Numbers & Runoffand Time of Concentration routines. When allthe inputs are entered, click on the Calculatebutton to obtain the peak flow at the bottomline. The peak flow value can then be used forDetention Pond Sizing or Channel Design.


Prerequisite: None.

Keyboard Command: peakflow

File Names: \lsp\peakflow.lsp, \lsp\peakflow.dcl,\lsp\cntr_grd.arx

Graphical Peak Discharge

Project: Parking By: TWDate: 11/13/95Location: West Checked:Date:Developed

1. Data: Drainage area:....................A = 27.1500 Acres Runoff Curve Number:.............CN = 70 Time of Concentration:...........Tc = 0.752. Frequency........................yr = 1003. Rainfall,P(24-hour)..............in = 6.004. Initial abstraction, Ia............ = 0.85715. Compute Ia/P....................... = 0.14296. Unit peak discharge, qu......csm/in = 410.227. Runoff,Q.........................in = 2.80528. Pond & swap adjustment factor,...Fp = 1.009. Peak Discharge,qp...............cfs = 48.8172


Peak Flow - Tabular Hydrograph Method

FunctionThis command calculates peak flow using the tabular hydrograph method from the TR-55program. The program is run through the dialog shown below. The Curve Numbers & Runoff andTime of Concentration routines can be used to calculate the subarea input values. When all theinputs are entered, click on the Calculate button. The input values can be saved to a file by clickingthe Save button. Then the Load button can be used later to recall these entered values. The peakflow report lists the flow for each subarea at different time. The peak flow value is listed at theend of the report. This value can then be used for Detention Pond Sizing or Channel Design.

See the TR-55 manual for more details on this routine. One difference between SurvCadd andthe TR-55 example is that SurvCadd interpolates the flow for the subarea Ia/P between the twonearest table Ia/P values whereas TR-55 uses the one closest Ia/P table entry. Consider a subareawith an Ia/P value of 0.14 and table entries of 100 cfs at 0.1 Ia/P and 75 cfs at 0.3 Ia/P. TR-55would use 100 cfs from the nearest 0.1 Ia./P entry. SurvCadd would interpolate between 100 and75 cfs resulting in 95 cfs.

Pull-Down MenuLocation: Water-shedP r e r e q u i s i t e :None.Keyboard Com-mand: peakflow

File Names:\ lsp\peakflow.lsp,\lsp\peakflow.dcl,\lsp\cntr_grd.arx


Peak Flow Tabular Hydrograph MethodSubarea Drainage Time of Travel Downstream Travel Rainfall Curve Runoffname area concen- time for subarea time number (sq.mi.) tration subarea names summation1 0.3000 1.50 0.00 3,5,7 2.50 6.00 65 2.352 0.2000 1.25 0.00 3,5,7 2.50 6.00 70 2.813 0.1000 0.50 0.50 5,7 2.00 6.00 75 3.284 0.2500 0.75 0.00 5,7 2.00 6.00 70 2.815 0.2000 1.50 1.25 7 0.75 6.00 75 3.286 0.4000 1.50 0.00 7 0.75 6.00 70 2.817 0.2000 1.25 0.75 0.00 6.00 75 3.28Time 11.0 11.3 11.6 11.9 12.0 12.1 12.2 12.3Subarea Discharge (cfs)1 0 0 1 1 1 1 1 22 0 1 1 1 2 2 2 23 1 1 2 2 2 2 3 34 2 2 3 3 4 4 4 55 3 4 5 7 7 8 9 106 4 6 7 10 11 11 12 147 6 8 11 15 18 24 34 51Total 17 23 30 40 45 53 65 87

Time 12.4 12.4 12.6 12.7 12.8 13.0 13.2 13.4Subarea Discharge (cfs)1 2 2 2 2 3 3 3 42 2 2 3 3 3 4 4 53 3 3 4 4 5 6 7 114 5 6 6 7 7 9 11 165 11 13 16 20 26 48 80 1156 16 19 23 29 39 74 127 1867 75 104 137 165 184 202 173 139Total 114 149 189 230 267 345 406 475




Peak Discharge: 692 cfs


Peak Flow - Rational Method (General)

FunctionThis command calculates peak flow usingthe rational method, Q=CIA. The programis run through the dialog shown below.Depending on your area, there are differentmethods for determining the Intensity ofRainfall which you will need to know forthis routine. The weighted Runoff Coeffi-cient or C-factor can be calculated by theCurve Number & Runoff routine. The peakflow value can then be used for DetentionPond Sizing or Channel Design.


Prerequisite: None.

Keyboard Command: peakflw3

File Names: \lsp\peakflw3.lsp, \lsp\hydro.dcl,\lsp\cntr_grd.arx

Rational Peak DischargeProject: Parking By: TW Date: 11/13/95Location: West Checked: Date:Developed1. Data: Drainage area:....................A = 27.1500 Acres Weighted Runoff Coefficient:......C = 0.400 Intensity of Rainfall:............I = 2.10 in/hr2. Peak Discharge,.................cfs = 22.8060

Peak Flow Rational Method Report


Peak Flow - Rational Method Kentucky

FunctionThis command calculatespeak flow using the ratio-nal method, Q=CIA, withrainfall intensity coeffi-cients specific to regionsof Kentucky. The programis run through the dialogshown below. Theweighted Runoff Coeffi-cient or C-factor can becalculated by the CurveNumber & Runoff routine.The peak flow value canthen be used for DetentionPond Sizing or ChannelDesign.

Pull-Down Menu Location:WatershedPrerequisite: None.

Keyboard Command: peakflw2

File Names: \lsp\peakflw2.lsp, \lsp\hydro.dcl, \lsp\cntr_grd.arx

Watershed Settings (Save and Load)

FunctionThese commands save and load watershed parameters to a data file with a .HYD file nameextension. The watershed values include settings from the commands in the top portion on theWatershed menu such as rainfall, storm type, weighted curve number. These commands allowyou to recall these values after reloading the drawing at a later time.


Prerequisite: None.

Keyboard Command: saveshed, loadshed

File Names: \lsp\loadshed.lsp, \lsp\saveshed.lsp


SEDCAD Draw Flow Polylines

FunctionThis command draws polylines in the SEDCAD layer that represent flow lines. When drawinga network of flow lines, first draw the main branch. Then begin drawing the other flow lines fromthe top of flow and use the Join option to connect onto the main branch. Draw Flow Polylinesis the first command in a series that produce the Junction, Branch, and Structure labels forSEDCAD.

PromptsEnd/Pick point: pick a pointUndo/End/Join/Pick point: pick a pointUndo/End/Join/Pick point: pick a pointUndo/End/Join/Pick point: Press EnterDraw another flow polyline (<Yes>/No)? Press EnterEnd/Pick point: pick a pointUndo/End/Join/Pick point: pick a pointUndo/End/Join/Pick point: JoinSelect flow polyline at place to join: pick the main branch at the junctionDraw another flow polyline (<Yes>/No)? No

Pull-Down Menu Location: Watershed, SEDCAD Structure Layout>

Prerequisite: None.

Keyboard Command: sedcad1

File Names: \lsp\poly3d.arx

SEDCAD Locate Structures

FunctionThis command is the second step for creating the SEDCAD layout. Locate Structures placestriangle symbols on flow polylines that represents structures for SEDCAD.

PromptsSymbol size <4.0>: Press EnterPick location on flow polyline for structure: pick a point on a polylinePick location on flow polyline for structure: pick a point on a polyline


Prerequisite: flow polylines


File Names: \lsp\hydro1.lsp


Label Structure Layout

FunctionThis com-mand is thethird and fi-nal step forcreating theS E D C A Dlayout. La-bel Struc-ture Layoutdraws textlabels forthe junc-t i o n s ,branches ,and struc-tures in thenetwork. Aj u n c t i o n ,branch, ands t r u c t u r ereport isalso gener-ated. Flowpo ly l i ne sand struc-ture sym-bols mustbe drawnbefore run-ning this routine. This command uses the labeling rules as described in the SEDCAD manual.

PromptsSymbol size <4.0>: Press EnterJunction offset tolerance <10.0>: Press Enter. Flow lines that meet the main branch withinthis distance of each other are considered the same junction.Select flow polylines and structure symbols.Select objects: pick the polylines and symbolsJ5,B1,S1J4,B2,S1J4,B1,S1

Example of labeled SEDCAD structure layout


SEDCAD

FunctionCivil Software Design is the author of Sedcad which is sold separately from SurvCADD. Sedcadis a comprehensive hydrology and sedimentology package, useful for all varieties of runoff andsediment control design calculations. Sedcad can be run directly from the SurvCadd hydrologymenu. The directory where Sedcad is installed must be defined in the Configure SurvCaddcommand.

J3,B2,S1J3,B1,S2,S1J2,B2,S1J2,B1,S2,S1J2,B3,S1J2,B1J1,B2,S1J1,B3,S1J1,B4,S1J1,B1Write report to file (Yes/<No>)? Press EnterWrite report to printer (Yes/<No>)? Press Enter


Prerequisite: flow polylines and structure symbols




Draw Flow Polylines (TR-20)

FunctionThis command draws polylines that represent flowlines. When drawing a network of flow lines, firstdraw the main branch. Then begin drawing the otherflow lines from the top of flow and use the Join optionto connect onto the main branch. Always draw theflow polylines from the highest to lowest elevation(in the direction of flow). Draw Flow Polylines is thefirst command in a series that produce the watershedschematic for TR-20 Hydrograph Development. Theseflow polylines only represent the layout of the water-shed and they do not need to be drawn to scale. Aftereach flow polyline is drawn, the program prompts forthe drainage area, curve number and time of concen-tration of the branch associated with that flowpolyline. This data is used in the RUNOFF statementin TR-20. The flow polyline label shows the area overthe curve number and time of concentration.

PromptsText size <4.0>: press Enter. This will be the text size for the flow polyline labels.End/Pick point: pick a pointUndo/End/Join/Pick point: pick a pointUndo/End/Join/Pick point: pick a pointUndo/End/Join/Pick point: Press EnterDrainage Area DialogDraw another flow polyline (<Yes>/No)? Press EnterEnd/Pick point: pick a pointUndo/End/Join/Pick point: pick a pointUndo/End/Join/Pick point: JoinSelect flow polyline at place to join:pick the main branch at the junctionDrainage Area DialogDraw another flow polyline (<Yes>/No)? No


Prerequisite: None.

Keyboard Command: trflow


Main flow polyline with one branch


Locate Structures (TR-20)

FunctionThis command places a structure on a flow polyline of the watershed schematic for TR-20Hydrograph Development. The program prompts for elevation, discharge and storage data forthe structure which is equivalent to the TR-20 STRUCT table data. At the bottom left of thedialog, the Water Elevation at T=0 is the water-surface elevation at the structure at the beginningof the storm. A triangle structure symbol that contains the structure data is drawn on the flowpolyline. The File button can be used to read the stage-discharge in .STG files and the stage-storage in .CAP files. The storage or discharge in the file is added to the table. Stage-storage filescan be created with the Bench Pond Design, Valley Pond Design and Calculate Stage-Storagecommands. Stage-discharge files can be created with the Drop Spillway, Design Channel andDesign Culvert routines.

PromptsSymbol size <4.0>: Press EnterPick location on flow polyline for structure: pick a point on a polylineStructure Data DialogPick location on flow polyline for structure: press Enter

Pull-Down Menu Loca-tion: Watershed

Prerequisite: flowpolylinesKeyboard Command:trstructFile Names:\lsp\hydro1.lsp, \lsp\hydro.dcl& \lsp\poly3d.arx


Locate Reach

FunctionThis command places a reach on a flow polyline of thewatershed schematic for TR-20 Hydrograph Development.The program prompts for the reach length, end area coeffi-cient and exponent M. These variables are explained in theTR-20 manual. A square reach symbol that contains the reachdata is drawn on the flow polyline. The reach labels show thelength above the end area coefficient and exponent M.

PromptsSymbol size <4.0>: Press EnterPick location on flow polyline for reach: pick a point ona polylineReach Data DialogPick location on flow polyline for reach: pressEnter



Keyboard Command: trreach

File Names: \lsp\hydro1.lsp, \lsp\hydro.dcl & \lsp\poly3d.arx

Reach on flow polyline

Edit Layout Element

FunctionThis command allows you to edit the data stored with a part of the watershed schematic. For flowpolylines the area, curve number and time of concentration can be changed. For structures theelevation, discharge and storage can be changed. For reaches, the length, end area coefficient andexponent M can be changed.

PromptsSelect flow line, structure or reach to edit: Pick a flow polyline, structure symbol or reachsymbol



Keyboard Command: tredit


Hydrograph Development

FunctionThis command routes runoffthrough branches, structures andreaches. The dialog first promptsfor storm data. Descriptions ofthese variables are in the TR-20manual. After the dialog, selectthe flow lines, structures andreaches that were created by theDraw Flow Polylines, LocateStructure and Locate Reach com-mands. The program then createsa TR-20 input file called temp.datin the SurvCadd exec directoryand runs TR-20. The output can besent to a file, printer or screenfrom the report viewer.

Hydrographs are created at eachflow line junction, structure andreach. The hydrographs are storedin files with a .h1 extension. Thesefiles are named automatically andplaced in the SurvCadd data di-rectory. Hydrographs entering a structure start with an 'S' and then the structure number. Thestructure number is labeled next to the structure symbol. Hydrographs entering a junction startwith a 'J' and then the junction number. The junction number is also labeled next to the junction.The next part of the file name is either 'RUN' for runoff, 'OUT' for the hydrograph at the end of

Watershed schematic with two flow lines, onestructure and two reaches to be used as input forHydrograph Development


Single Runoff Hydrograph

FunctionThis command creates a hydrograph for the runoff of one drainage area. The Use TR-20 togglein the upper left chooses between using TR-20 and using the SCS method from A Method forEstimating Volume and Rate of Runoff in Small Watersheds. The hydrograph is stored in a filewith a .h1 extension that can be drawn with the Draw Hydrograph command.

PromptsCalculate HydrographDialogSelect Hydrograph FileDialog

Pull-Down Menu Location:WatershedPrerequisite: None

Keyboard Command: calchgrf

File Names: \lsp\calchgrf.lsp,\lsp\poly3d.arx, \lsp\hydro.dcl &\exec\tr20.exe

the structure, 'REA' for the end of a reach, or 'ADD' for the combination of two hydrographs. A moredetailed description of the hydrograph is in the third line of the hydrograph file.

PromptsCalculate Hydrographs DialogSelect flow polylines, structure and reach symbols.Select objects: pick the objects


Prerequisite: A flow polyline. Structures and reaches are optional.

Keyboard Command: runtr20

File Names: \lsp\runtr20.lsp, \lsp\poly3d.arx, \lsp\hydro.dcl & \exec\tr20.exe


Draw Hydrograph

FunctionThis command draws ahydrograph from a hydrographfile (*.h1) that is created bySEDCAD, the Hydrograph De-velopment, or the Single RunoffHydrograph command. Multiplehydrographs can be drawn on thesame grid by first running DrawHydrograph with the Draw Gridoption on. Then run DrawHydrograph for each additionalhydrograph with the Draw Gridoption off and pick the samestarting time and same lower leftgrid corner.


FunctionThis command is designed to allow the user to create HEC-2 input files. HEC-2 is a computerprogram prepared by the Corps of Engineers to compute water surface profiles in non-prismaticstream and river channels. The bulk of the input to the HEC-2 program consists of cross-sectional data of the stream and adjacent flood plain. It is in the preparation of this data thatSurvCADD can be of real assistance.

The Prepare HEC-2 Input File routine converts *.sct files prepared in SurvCADD to HEC-2 inputdata. The files are given the same name as the *.sct file used to make them and are given the *.h2ifile extension. Each line in the HEC-2 text file, begins with a two letter identifier, followed by thecorresponding data in a fixed format. Each segment of the stream is represented by a group of lines.The header for the section is the “X1” line. On this line is recorded the general information aboutthe section and the channel reach. The “X1” line may be preceded by several change channel lines.“NC” cards as the only representative of the change lines in this routine. This line defines the streamfrictional resistance by the Manning’s ‘n’. The “X1” line is followed by a series of “GR” linesrepresenting the ground at the section. This representation is a list of elevations and distancesfrom a baseline. The baseline is on the left side facing downstream and the distances are positivevalues, increasing as the section is read from left to right.

Sections are identified in HEC-2 by a 6 character identifier on the “X1” line. The sct2hecconversion program uses the integer value of the centerline station as the identifier for thesection. This allows sections at stations up to 9,999+99. This corresponds to study reaches of189 miles. For the sake of standardization horizontal distances along the section are taken tothe even foot and elevations to the 0.1 foot.

Prepare HEC-2 Input File

PromptsRange of Times: <0.0 - 49.998>Starting time <0.0>: Press EnterEnding time <49.998>: Press EnterDraw Hydrograph settings dialog boxPick starting poind for axis <0.0 , 0.0>: pick a point


Prerequisite: a hydrograph file

Keyboard Command: hydrogrf

File Names: \lsp\hydrogrf.lsp, \lsp\makegrid.lsp, \lsp\hydro.dcl


The next piece of information on the “X1” line is the number of points on the following “GR” cards.The limit of 100 points in HEC-2 is checked and an alert box generated if applicable. The next twoitems of data on the “X1” card are the stations of the left and right banks of the stream. In HEC-2 the points must be points on the GR cards. Therefore these entries are made by selecting pointsfrom the list of points.

The last data on the “X1” line is the lengths of the channel and overbanks within the reach fromthe prior section to the current section. The distance between the sections is determined by thedifference in stations of the sections on the *.sct file. This distance is presented as the defaultvalue for the length of both overbanks and the channel. On the first section these three valuesare 0, which tells HEC-2 to begin a profile. If the original polyline defining the *.xms file wasalong the thalweg of the channel then the channel length default is correct. The overbank lengthsshould be edited for curves in the channel.

A SurvCADD *.sct file may be made by any one of the seven methods listed on the Sections pull-down of the Section-Profile module. A *.sct file made by any of these procedures can beconverted to a *.h2i file. The procedure to create an *.sct file from a surface model begins withestablishing a polyline as the centerline by which the sections will be oriented and spaced. Thisshould be along or near the thalweg, or center of flow, of the stream and drawn in an upstreamdirection. From this polyline a *.mxs file is created. The width and location of sections at regularintervals and at special stations are defined in this step. It is this *.mxs file which SurvCADD usesto define the inundated regions latter in the hydrology modeling. Then the sections are cut andthe *.sct file created by the normal means in SurvCADD. SurvCADD allows limiting the numberof points in the section. Since HEC-2 has a limit of 100 points in a section, that limit should be


observed when cutting the sections.

When running the convert a *.sct file to a *.h2i file, an input *.sct file is first requested by a fileselection dialogue box. Then an offset distance prompted for on the command line. Thisdistance should be larger than the greatest right offset used in making the *.sct files. Thehorizontal distances, called stations in HEC-2, along the cross-section must all be positivenumbers increasing across the section. The HEC-2 section represents the ground as a left toright section looking downstream. For the HEC-2 computations the sections are read from thedownstream end working upstream. Thus the need to begin the *.mxs file at the downstream endof the stream reach. (The preceding applies to the predominate case of subcritical flow and isreversed for analysis of supercritical flow.)

As each section is read the user is presented with a dialogue box to edit data specific to eachsection. In the upper left corner of the dialogue box are 3 edit boxes for the channel and overbankreach lengths. The distance between sections is used as the default in all three boxes. The usermay edit these values to correspond to channel curvature or other conditions as hydraulicallywarranted. Below these are five boxes with the Manning’s ‘n’ coefficients for the channel andoverbanks separated by the top of bank stations. The ‘n’ values may be edited just like any editbox. The top of bank stations are assigned values by selecting points from the list of all the pointsin the section displayed along the right of the dialogue box. The first station selected is assumedto be the left bank and the second the right bank. If the user changes his mind about the bankstation, after the first two selections from the list the user can select either right or left bank.These boxes do not update their display until the user has selected another box to edit. The topof bank stations must correspond to points on the following “GR” cards, which is why user entryof any number is not allowed. The bank stations are used by HEC-2 to apply the Mannings ‘n’values assigned by the user.

A complete, but minimal, input file is created by this conversion routine. Certain default valueswere selected and written to the output file to make it a complete file. These are:

Begin computations using the slope/area method with 0.01 ‘/’ slope;Flow = 500 cfs;Only a single profile will be computed;On the “T2” card the input *.sct file is recorded;At each section the default top of bank stations are the first and last points.

Older versions of HEC-2 for PCs (322k in size) can be run by shelling out of AutoCad. Newerversions (as distributed by Hastead Methods and others) use the Pharlap extender to accessextended memory and will now run in an AutoCad shell.

The user will normally need to edit the *.h2i file to represent the flows and beginning conditionsto model and the type of output desired. Other parameters which may be added to the input fileare:

Contraction and expansion coefficients for energy loss,Multipliers to Manning’s ‘n’,Call printer plots,


Channel modifications,Bridges by normal or special methods,Custom output formats,Ice conditions andEncroachments.

All of these items can be entered into the file on the appropriate cards using the DOS Editprogram, the Display-Edit selection in SurvCADD or a similar editor. The output of the conversionis in the fixed 80 column format expected by the HEC-2 program. If the user is making significantchanges or additions to the data it may be advisable to use the FREE format option for hand entereddata.

The default values for Manning’ ‘n’ are 0.020 in the channel and 0.030 for both overbanks. Thesecan be edited for the first section and the edited values will apply to all following sections.Editing the values in latter sections will create a new “NC” line to be written ahead of that section.

The availability of easy input data to the HEC-2 program will change the way engineers use HEC-2. In the past the location and number of sections was carefully considered to get the best resultwith the fewest, most representative, sections. Now a common topographic survey of thechannel reach can provide easily sections at close intervals. Changes to the stream geometry canbe easily modeled in the site plan and converted to HEC-2 data for analysis. This practicallyeliminates the need for channel improvement “CI” lines.


Prerequisite: Cross section .sct file.

Keyboard Command: sct2hec

File Names: \lsp\sct2hec.lsp, \lsp\hydro.dcl

HEC-2 Programs

FunctionThe HEC-2 programs include HEC-2, EDIT-2, PLOT-2, and SUMPO. These programs weredeveloped by the Corps of Engineers and their documentation is separate. The programs aredistributed with the Hydrology module and are placed in the SurvCADD EXEC directory. The HEC-2 programs can be placed in another directory and run from SurvCADD by setting the HEC-2directory in the Configure SurvCadd command.


Draw Watermark

FunctionThis command draws a closed polyline representing the high watermark as calculated by HEC-2. The program uses the water depth at each station from the HEC-2 output file, the existingsection file and a centerline polyline.

PromptsSelect Section File Cross-sections of the surfaceSelect HEC-2 Output File This is a user-specified file created in HEC-2Select centerline polyline: pick the polylineStarting station of centerline <0.0>: Press Enter


Prerequisite: a section file, HEC-2 output file, and a centerline polyline

Keyboard Command: drawhec

File Names: \lsp\regrade.arx

Prepare HEC-RAS Input File

FunctionThis program reads cross-section files and the corresponding MXS files (please see the materialon Sections in Chapter 6 of this manual) and creates input files that can be used to run the HEC-RAS program for river analysis. The HEC-RAS program could be considered to be an advancedWindows-based version of the HEC-2 program. This program makes it easier for CADD and GISsystems to import their data directly for river network analysis. It is also very convenient becausethe output from the program can be exported directly to CADD programs where this data can beused to create water surface models for inundation mapping.

Data Format :HEC-RAS input files consist of three data sections :* A header, containing data relevant to all sections of the data in the file.* A description of the stream network, containing reach locations and connectivity.* A description of the model cross-sections, containing cross-section location and geometricdata as well as additional HEC-RAS modelling information.

The header information is mainly for the purpose of identifying the project and is mostly notused by the program. The only important information needed by the program is the "Units"section and the value must be "ENGLISH" or "METRIC".


The network is modelled as a set of interconnected streams. Each stream is a set of interconnectedreaches. Each reach, hence, MUST have a unique Stream ID and Reach ID.

The Stream Network section contains a series of Point Numbers and the correspondingcoordinates. In addition, this section has information pertaining to each Reach. For each Reach,the following information is provided :* Stream ID and Reach ID. These are 16 character alphanumeric strings. Together these two itemsuniquely identify a Reach.

* Starting (FROM or upstream) point and ending (TO or downstream) point of the Reach. TheFROM point and TO point here are given by their Point Numbers, as identified above.

* The coordinates on the Centerline of the Reach, starting with the FROM point coordinates andending with the TO point coordinates.

The Cross-Sections portion of the input file contains data describing the geometric propertiesat each cross section in the network. The following information is provided at each Cross-Section :

* Stream and Reach ID, toidentify which Reach the Cross-Section is on.

* Station, position of the Cross-Section, relative to the Stream.The Station is taken as thedistance from the currentstation to the end of the stream.For this purpose, the streamMUST be drawn Downstreamto Upstream. THIS IS THEMOST FUNDAMENTALREQUIREMENT OF THEPROGRAM. If the Stream isdrawn in the other direction,then, it must be reversed usingthe command Reverse Polylineunder Modify>PolylineUtilities

* Cut Line : Series of pointcoordinates, identifying thesurface line of the Cross-Section. HEC-RAS identifies


the cross-sections as going from left to right as seen from upstream to downstream. The user onlyneeds to make sure that the stream network is drawn in the right direction (downstream to upstream);all other conventions are taken care of by the program.

Modelling Guidelines :Some additional guidelines in drawing the river network in the CAD so as to model correctly forHEC-RAS :

* All the Reaches in the Stream Network must be connected at common End Points; disjointedStream Networks are not allowed; Reaches must also NOT cross each other.* Streams cannot contain parallel flow lines. If three reaches connect at a node or End Point, atthe most TWO of them can have a common Stream ID. (Please note that a Reach is uniquelyidentified by a Reach ID and a Stream ID).* Cross-Section lines can cross a Reach line only once and cannot cross other X-section lines.

Program Execution:Before starting the "Prepare HEC-RAS InputFile" command, all the SCTfiles and theircorresponding MXS files should have beencreated for every Reach. Points where twostreams meet would form a node in thestream network. Sections of a stream betweensuch nodes should be modelled as a Reach.and drawn as a separate polyline. Now, changeto the Section-Profile Menu. The MXS filefor each Reach is created using the commandInput Edit Section Alignment under theSections pulldown menu. Based on any of themethods for creating section files (describedin chapter 6 of this manual), the Section filefor the Reach is created. The user must managethe .MXS file and the .SCT file correspondingto each Reach. At this point, a Stream ID andReach ID may be assigned to every Reach,based on a convenient naming convention,which is entirely up to the user. These IDswould be needed when creating the HEC-RAS input file.

The program starts by asking the user for the Header information. The user can input as muchinformation in this dialog box as possible. The "Units" can be "Metric" or "English".Next, the user will be prompted to enter the .MXS and .SCT file names, the Stream ID and ReachID for each Reach that you wish to add to your model. The user can enter data (IDs and file names)for as many Reaches as wished. That is, the user can create input files for each Reach individuallyand import them individually into HEC-RAS or create a combined input file for all the Reaches in


the Stream Network. This makes it very convenient to add more Reaches to the HEC-RAS modelat a later stage or do the analysis for various sections separately. After entering as many Reachesas needed, the user presses "Exit" to stop entering any further Reaches and to continue with theprogram execution.

On pressing "Exit", the user is prompted for the Input HEC-RAS file to be created. HEC-RASinput files have a .GEO extension. When the file is chosen at the prompt, the program createsthe input file for HEC-RAS. This file can be used to import geometric data into HEC-RAS, asdescribed below. You must have HEC-RAS version 2.0 or higher installed on your computer.

HEC-RAS :After starting HEC-RAS, select "Geometric Data" from under the "Edit" pulldown menu. Thisbrings up a Geometric data editor, complete with a CAD screen and various options. From the"File" pulldown menu of the Geometric data editor, choose the "Import Geometric Data -> GISFormat" command. This brings up a file browser and allows you to choose a geometric data file.Choose the .GEO file just created. This should load the geometric data into HEC-RAS, whichis then converted into a CAD format drawing and shows up in the Geometric Data Editor in theform of a Stream network, with EndPoint, Stream ID and Reach IDs, Cross Sections stationinginformation, along with directions of in each Reach.

At this point, the user can edit several aspects of the data where Survcadd only provides defaultvalues. Specifically, the Bank Positions and overbank reach lengths can be adjusted here. Inaddition, the Mannings coefficient has to be entered for all the cross-sections for all the left,right and center flows. As of HEC-RAS release 2.0, there is no way to input a default value forthe Mannings coefficient, but this situation may improve in future releases of HEC-RAS, inwhich case the Survcadd program will be modified immediately.

Other data that needs to be modified is the location of the left and right banks. By default, theleft bank is given to be at 0.45 times the cross-section length and the right bank is given to beat 0.55 times the cross-section length. In order to correctly model the channel geometry, thelocation of the banks must be accurately defined for each cross-section. This can be done byclicking on the "Cross-Sections" icon in the "Geometric Data Editor" or by clicking with the leftmouse on the cross-section to be edited. This brings up all the geometric data related to thatparticular cross-section, which may be edited as required.


The left and right overbank lengths are defaulted to equal the centerline length ( which may notbe equal in the case of a sharp bend in the stream). These values can also be edited in the samecross-section editor as mentioned above.

Geometric data can be stored by running "Save Geometric Data" from the "Geometric DataEditor". The file extension assigned for Geometric data files is *.g*, which means thatsuccessive geometric data files will be given file extensions in a numeric sequence, beginningwith *.g01.

Information specific to each analysis can be entered in the "Steady Flow Data Editor", which canbe brought up by selecting "Steady Flow Data" from the Edit pulldown menu of the main HEC-RAS window. The data that can be selected here are the number of profiles that need to be run,flow in each reach for each profile simulation and the Hydraulic boundary conditions at eachReach for each Profile simulation. This information is stored in a file with the extension *.f01and so on for successive files.

Once all the geometric data and Steady flow data has been entered, the simulation can be run byselecting "Steady Flow Analysis" from the "Simulate" pulldown menu in the main HEC-RASwindow. After selecting the type of flow condition (sub-critical, super-critical or mixed), theuser selects the "Compute" button to complete the analysis. If there are errors or seriouswarnings, the program reports them in a text editor. Otherwise, the program shells out to a DOSscreen and completes all the necessary calculations. Several options are available for viewingand editing output from the HEC-RAS program, which are best explained in their manual.

44 Hydrology Module - Structure Commands

Structure Commands

Shown here is the Structure pull-down menu. The Design Benchand Valley Pond commands aredescribed in the DTM-ContourModule section.

Hydrology Module - Structure Commands Page 7-45

Detention Pond Sizing

FunctionThis command calculates the runoff and storage volumes for a detention pond. The program usesthe method from the TR-55 program as described in the Urban Hydrology for Small Watershedsmanual.

The command is run through the dialog box shown here. When the input values are filled in, clickon the Calculate button to obtain the output values. The drainage area can be either entereddirectly or selected from AutoCad by clicking on the Select Area button and then selecting theclosed polyline from the screen. The peak inflow will use the value calculated in the Peak Flow-Graphical Method command. Likewise the runoff Q will use the value from the Curve Numbers& Runoff routine.

The output of this command, the storage volume value, can be applied to the Design Bench,Valley or Rectangular Pond routines.

Prerequisites: None

File Name: \lsp\det_pond.lsp

Keyboard Command: dpond

Pulldown Menu Location:Structure within Hydrology Menu


Rectangular Pond Design

FunctionThis program will draw rectangular ponds and calculate storage at any level in the pondcorresponding to top of pond, emergency spillway, principal spillway and sediment (cleanout)level. Elevations can be “reverse-calculated” based on requested storage amounts. All calcula-tions derive from input length-width and slope ratio values. Only one common ratio is used for theinterior pond slopes (e.g.. 1:1 or 2:1, etc.).

The program will output scaled and fully annotated plan view, section A-A and section B-Bdrawings, complete with principal and emergency spillways. For simplicity, the principal spillwayis considered to be a pipe spillway, and the emergency spillway is considered to be a flat-bottomweir spillway. If the pond in question has only one spillway, then the appropriate spillway elevationis entered in the dialog box, and the other spillway option is left blank.


There are two other output options available. The user can produce a table of storage values asan ASCII file output by selecting “Write Report”. This will include the “Required Freeboard” and“Peak Storm Event” values, which are used for the ASCII file output only. This information, in turn,can be read back into the drawing and plotted beside the pond details using TEXT IMPORT locatedunder the MISC pulldown menu. The last output option is the “Pond Capacity File”, which createsa “.CAP” file which can be plotted using the file option within the POND STAGE STORAGE CURVEroutine located under the POND pulldown menu. The net effect of the Rectangular Pond Designroutine is that you can calculate necessary pond storages, plot the pond detail drawings, write outand import the ASCII text summary and plot the pond stage-storage curve, all in about 3 minutes.

There are ways to use the routine in “shortcut” form to draw ponds. Simply by completing 3 dialogentries (base width, base length and total depth) the user can draw the plan view, section A-A andsection B-B. This is why the Pond Elevation items are considered “optional”. The programs canalso be used as a pond storage calculator. Any of the Pond Elevation options (excepting peakstage), when completed will lead to recalculated storage values. Storage values can likewise bealtered and will lead to recalculated elevations. The act of pressing enter inside a dialog boxactivates the calculation process. If there is no need to plot the pond detail drawings, the cancel“button” in the dialog can be selected following calculations.

PromptsThe program begins by presenting the dialog. One effective way to fill out the dialog boxes is topick the upper left box and work down and through the options by pressing the tab key after eachentry. If all items are filled out as shown, the following prompts will appear:Path/File Name for Report: POND.TXTPath/File Name for Pond: PONDEnter Scale Factor for Pond Drawing(s) <1>: Press EnterDraw Plan View: (<y>/n): Press EnterPick Lower Left Corner:Plot Cleanout and Spillway Lines (<y>/n): Press EnterPick Location of Principal Spillway:Draw Section A-A Horizontal (y<n>): yPick Left Location of Section A-A:Pick Right Location of Section A-A:Draw Section B-B Vertical (y/<n>): yPick One Side of Section B-B:Pick one Side of Section B-B:Pick Upper Left Corner for Section A-A:Plot Cleanout and Spillway Lines (<y>/n): Press EnterPick Upper Left Corner for Section B-B:Plot Cleanout and Spillway Lines (<y>/n): Press EnterIf no Section A-A or Section B-B identifier lines are drawn, no section A-A or Section B-B detailswill be drawn. Thus if you want Section A-A only, say "y" to Draw Section A-A Horizontal but"n" or Enter to Draw Section B-B Vertical. If you entered only length, width and depth in the originaldialog, the resultant prompting would be:Enter Scale Factor for Pond Drawing(s) <1>: Press Enter


Section A-A:Pick Upper Left Corner of Section B-B:The resultant plots produced by the entries in the above dialog are shown above.

Keep in mind that the scale factor, if other than 1, will enlarge or reduce the size of the detail drawingsto suit the users needs, yet will annotate dimensions correctly in all cases.

The imported text based on the output ASCII file POND.TXT (located in \SC12\WORK by default)would appear as follows:Top of Pond Elevation: 1070.00 feetPeak Stage (25th year-24 hour Storm Event): 1069.45 feetIncludes 1.00 feet of FreeboardEmergency Spillway Elevation: 1067.00Emergency Spillway Bottom Width: 10.00Principal Spillway Invert Elevation: 1065.50 feetPrincipal Spillway Diameter: 42.00 in.Principal Spillway Slope: 2.00 %

Sediment Pool (Cleanout) Elevation: 1064.00 feetBottom of Pond Elevation: 1060.00 feetStorage Volume at Emergency Spillway: 0.2990 ac.ft.Storage Volume at Principal Spillway: 0.2150 ac.ft.Storage Volume at Sediment Pool: 0.1430 ac.ft.The routines are fully metric and will substitute meters and cubic meters appropriately for feet andacre-feet. Pipe sizes, however, will default to diameters in inches.

Pull-Down Menu Location: Structure menu in Hydrology Module

Prerequisite: None

Keyboard Command: rpond

File Name: \lsp\drawpond.lsp, \lsp\drawpond.dcl

Draw Plan View? (<y>/n): Press EnterPick Lower Left Corner:Draw Section A-A Horizontal (y/<n>): yPick Left Location of Section A-A:Pick Right Location of Section A-A:Draw Section B-B Vertical (y/<n>): yPick One Side of Section B-B:Pick Other End of Section B-B:Pick Upper Left Corner of


Drop Pipe Spillway Design

FunctionThis program calculatesthe spillway discharge atdifferent water eleva-tions. As the water eleva-tion initially rises abovethe riser, the flow is con-trolled by weir flow. Athigher water elevationsthe flow is under orificecontrol. When the barrelflows full, the flow is con-trolled by full pipe flow.Given the water elevationand spillway dimensions,the program calculatesthe type of flow and dis-charge.

The Calculate button will read the values in the dialog, calculate the flow and report this flowvalue at the bottom of the dialog. The Report button will generate a report of the input values andcalculated flows. The File routine will create a stage-discharge (.stg) file. The Draw function willdraw and label the drop pipe spillway in the drawing at the specified scale. The Graph buttoncreates a stage-discharge graph.

Prerequisites: None

File Name:\lsp\spillway.lspKeyboard Command:spillwayPulldown Menu Loca-tion: Structure withinHydrology Menu

1. Data: Pool elevation:............. = 976.00 ft Top of riser elevation:..... = 975.20 ft Bottom of riser elevation:.. = 973.00 ft Outlet elevation:........... = 968.00 ft Diameter of riser pipe:..... = 20.00 in Diameter of culvert pipe:... = 30.00 in Length of culvert:.......... = 145.00 ft Entrance loss coefficient:.. = 2.1600 Friction coefficient:....... = 0.0220 Weir coefficient:........... = 3.3000 Orifice coefficient:........ = 0.95002. Spillway discharge: Weir Flow Discharge......... = 12.36 CFS Orifice Flow Discharge...... = 14.87 CFS Full Pipe Flow Discharge.... = 23.50 CFS Spillway discharge.......... = 12.36 CFS


Pond Weir Spillway Design

FunctionThis program calculates the dimen-sions of a rectangular weir given theoutflow discharge. The default dis-charge uses the value from the De-tention Pond command. The weirwidth and depth are two free vari-ables. Enter a value for one and PressENTER. Then the value for the otheris calculated.

The weir design may optionally beapplied to a pond design. First entera Required Storage Volume whichcan come from the Detention Pondcommand. Then click Apply to Ac-tual Pond and choose a Storage Ca-pacity File (.cap). This .cap file can becreated by Bench or Valley PondDesign and by the Stage-Storagecommand. The program then com-putes the elevation at the requiredstorage volume and the correspond-ing elevation for the bottom of theweir given the weir depth.

When the Draw Spillway Detail option is checked, a drawing of the weir is created as shownbelow.

Prerequisites: None

File Name: \lsp\spilweir.lsp

Keyboard Command: weir

Pulldown Menu Location:Structure within HydrologyMenu


Design Spillway

FunctionThis command creates a spillway with 3D polylines in the drawing. The program uses a surfacemodel of the area for the spillway, a spillway centerline and spillway dimensions (width, elevation,etc.). The surface model of the area can be defined by contour polylines, points and 3D polylinesor can be created by the Design Bench or Valley Pond commands. The spillway dimensions canbe calculated by the Design Channel commands to meet the desired discharge. The amount of cutrequired to make the spillway is calculated and reported.

PromptsSource of surface model (File/<Screen>)? Press Enter. Use the File option to select a .grd file.Pick Lower Left limit of surface area: Pick lower leftPick Upper Right limit of surface area: Pick upper rightBe sure to pick these limits well beyond the area of the spillway centerline in order to make roomfor the outslopes.Make GRiD File DialogAfter selecting the limits of the disturbed area the program will generate a 3D grid that representsthe surface. Specify the grid resolution desired and select OK. Pick the spillway centerline:Select polyline that crosses the damPick a point within the pond: the program needs to know which end of the spillway centerlineis within the pondEnter slopes as percent grade or slope ratio (Percent/<Ratio>)? EnterEnter the side slope ratio <1.0>: Press EnterEnter the flow slope ratio <100.0>: Press EnterRange of existing elevations along spillway centerline.Enter spillway elevation <1476.5>: 1475.0. This is the entrance elevation of the spillwayEnter the spillway width <10.0>: Press Enter

Prerequisites: surface entities that model the pond

File Name: \lsp\pond.arx

Keyboard Command: spill

Pulldown Menu Location:Structure within Hydrology Menu

Spillway Report

Spillway inlet elevation : 1445.0000Spillway outlet elevation: 1445.0000Spillway width: 10.0000Side slope percent grade: 100.00, slope ratio: 1.00Flow slope percent grade: 1.00, slope ratio: 100.00

Spillway EarthWork VolumesTotal cut: 55.593 C.Y., 1501.00150 C.F.


Calculate Stage Storage

FunctionThis command calculates stage-storage values for a pond that is already drawn in the drawing.Before running this routine, the surface model for the pond must be created as a grid file with Make3D Grid File. A closed polyline for the perimeter of the pond is also required.

PromptsChoose Grid FileSelect the .grd file that models the pond surfacePick the top of dam polyline: pick the closed polyline perimeterChoose method to specify storage elevations (<Automatic>/Manual)? ManualRange of pond elevations: 367.07 to 383.63Enter stage elevation (Enter for none): 370Enter stage elevation (Enter for none): 374Enter stage elevation (Enter for none): 378Enter stage elevation (Enter for none): 382Enter stage elevation (Enter for none): Press Enter

Pond Storage VolumesWater Elev: 370.00, Pond Storage: 10290.113 C.Y., 6.37817 Acre Feet

Spillway added to valley pond


Pond for Calculate Stage Storage

Water Elev: 374.00, Pond Storage: 42518.613 C.Y., 26.35451 Acre FeetWater Elev: 378.00, Pond Storage: 81085.584 C.Y., 50.25966 Acre FeetWater Elev: 382.00, Pond Storage: 123449.853 C.Y., 76.51850 Acre Feet

Write stage-storage to SEDCAD file (Yes/<No>)? Press Enter

Prerequisites: surface entities that model the pond

File Name: \lsp\makegrid.arx

Keyboard Command: postpond

Pulldown Menu Location: Structure within Hydrology Menu


Draw Stage Storage Curve

FunctionThis routine draws a pond stage storage curve with pond elevation on the vertical axis and acre-feet of storage on the horizontal axis. It will plot and label the emergency spillway, principal spillwayand cleanout levels and will produce a table of storage data. The program will read and write a".CAP" file of pond storage, based on areas at each stage or elevation. CAP files (short for


"capacity") are made by Bench Pond Design, Valley Pond Design, Rectangular Pond Design andby the Stage Storage Curve program itself. These are the same files produced and read by SEDCAD,a popular hydrology and sedimentology program.

In addition to file-based inputs, the user can enter pond dimensions directly by length-width, areaat each stage, or volume at each stage. Since volume-based entry does not include area information,no CAP files are stored with this option. However, the curves plot in all cases. Plots are sized tofit on 8-1/2 x 11 sheets at the selected scale for plotting. They are particularly suited for permitapplications, so the program will prompt for permit number and page.

PromptsName of Pond <Sediment Control Structure No. 1>:Permit Application Number (e.g. 898-5252): A-17Permit Item Number (eg. 30.3): 10.1Page Number <1>:(File Input or known (A)rea, Length/Width (D)imensions or <V>olume: DStage No. 1Elevation: 940Width: 20Length: 60<Enter> for more, (R) to Revise, (E) to exit entry:If you made a mistake, you could enter R and then enter a revised Elevation, Width and Length.Otherwise, press Enter to continue.Stage No. 2Elevation: 945Width: 30Length: 70<Enter> for more, (R) to Revise, (E) to exit entry: Press EnterStage No. 3Elevation <950.00>: (the program "defaults to the last interval)Width: 40Length: 80<Enter> for more, (R) to Revise, (E) to exit entry: E (to exit!)A table appears, similar to the following: Inc. Vol Acc. VolElev Width Length Area Interval Avg. Area Ave Ft. Ave Ft. Stage940 20.0 60.0 0.028 0.00 0.028 0.000 0.000 0.00945 30.0 70.0 0.048 5.00 0.038 0.189 0.189 5.00950 40.0 80.0 0.073 5.00 0.061 0.304 0.494 10.00Areas are in acres. If the area method of entry were chosen instead, the user would have beenprompted for area at each elevation (stage), and the summary table would be blank under the widthand length columns. The file input method would also only report area values. Similarly, if entrywas by volume (in cubic feet), all width, length and area columns would be blank.


Calculate Storage or Elevation Points (y/<n>): yKnown (E)levation or known <s>torage:Storage (eg. 0.2 or %60 for 60% of total): %60Storage: 0.30 Elevation: 946.759Calculate Storage or Elevation Points (y/<n>): Press EnterPressing Enter moves on. The advantage of this option is the ability to find exact spillway andcleanout levels by experimenting with needed storages or desired elevations. For example,sediment cleanout levels are often set at 60% of total storage, which would be in this case 946.76.Elevation of Top of Structure: 950Elevation of Emergency Spillway: 948.5Elevation of Principal Spillway (Enter if same): EnterElevation of Cleanout Level: 946.76Is Above Data OK (<y>/n): Enter (n leads to re-entry of above 4 items)Range of Elevation: 10.0Desired Elevation Interval: 2 (for gridding purposes)Total Storage Range in Ac.Ft.: 0.4936Desired Storage Interval: 0.1 (for gridding purposes)Pick Starting Position: pick a pointEnter Scale of Drawing <50.0>: Press EnterText for Horiz. Scale <ACCUMULATIVE STORAGE (ac-ft)>: EnterThe user controls the axis labels. If you want the horizontal axis to read STORAGE, then you wouldtype this in the above. Similar prompts continue:Text for Vert. Scale <ELEVATION MSL>: Press EnterTitle of Plot <STAGE STORAGE CURVE>: Press EnterData Title <STORAGE VOLUME COMPUTATIONS>: Press Enter(C)ertification, (B)usiness Address or <E>xit: CCertification Line 1 <KY certification>: EnterA business address or typed-in certification can be entered here. If the user wanted to save adifferent default certification, lines 1008, 1009, 1014, 1020 and 1026 could be changed in the actualSTAGE-LSP ASCII file program. We normally don't recommend altering source code, but it caneasily be accomplished with a text editor.Store Pond Capacity File (y/<n>): yPath/File Name (no extension): POND (goes to the data directory by default).

Prerequisites: None

File Name: \lsp\stage.lsp

Keyboard Command: stage

Pulldown Menu Location: Pond within Hydrology Menu and Surface within Mining (CoalCad)Menu.


Draw Stage-Discharge Graph

FunctionThis program draws a stage-dischargegraph with the stage (water elevation)on the Y-axis and the discharge on theX-axis. The data to graph is read from astage-discharge (.stg) file which can becreated by several routines includingDesign Channel, Drop Spillway, etc.

First you are prompted to select a STGfile to draw. Then the program asks forthe ending discharge for the graph whichdefaults to the highest discharge in thefile. Next this dialog is displayed toenter the graph scale and intervals. Theheight of the annotation equals the hori-zontal scale times the Axis Text Scaler.

Prerequisites: Stage-Discharge file (.stg)

File Name: \lsp\hydrogrf.lsp, \lsp\hydro.dcl

Keyboard Command: stage2

Pulldown Menu Location: Structure within Hydrology Menu


Channel Design - Non-Erodible (Manning's Equation)

FunctionThis will compute channel depth, flow and velocity based on channel parameters such as sideslopes, base dimensions and Manning's n value. It handles triangular, trapezoidal , rectangular andirregular channels. Entry of a depth leads to calculation of flow and velocity. Entry of one of theother items (flow or velocity) will lead to calculation of the remaining items. In addition tofunctioning as a channel calculator, the program will output a typical section or detail of the channelas well as a report of the channel output. The routine also works in metric units. It applies to non-erodible channels, primarily. The user can select to output an ASCII file report of the channel inputand output values as well as a standard detail shown below for the above example.

PromptsWhen the routine is selected, the dialog box shown below appears. Select, for example, a trapezoidalchannel, equal sides, with side slopes of 3 (for 3:1) and a base dimension of 16. Then at the lower


left, plug a value of 4.5 for the depth. This will calculate a flow of 862 cfs and a velocity of 6.5 fps,as shown below.

To use the routine as a calculator, enter the known value in the lower left area of the dialog (flow,depth, or velocity), then press enter while still in the entered item. The other two items are thencalculated. Note that the routine will default to the last values used during the current SurvCADDwork session, and will capture the flow values calculated in Water Runoff under the WatershedPull-down. When entering the Manning's n value, a table of n values can be brought up and anappropriate Manning's selected.

Pull-Down Menu Location: Structure

Prerequisite: Use Drawing Setup to activate Metric or English outputs. If English is configured, theformula v=(1.486/n)(R^2/3)(s^1/2) is used, where n is the Manning's value, R is the water cross sectiondivided by the wetted perimeter and s is the slope ratio. If Metric is configured, the formula becomes v=(1.0/n)(R^2/3)(s^1/2) and outputs are in meters.Keyboard Command: channel1

File Names: \lsp\channel.lsp & \lsp\hydro.dcl


Channel Design - Erodible (Manning's Equation)

FunctionThis command uses the same Manning's equations as non-erodible channel design. In this case,the discharge and velocity are known. The velocity must be less than a maximum to prevent erosion.The program calculates the channel dimensions that meet the requirements.

First choose the channel and water type. Then either enter the Manning's n, velocity, and tractiveforce or select them from a table of channel types by clicking Select from Table. Also fill in the slopeand discharge. Finally, choose either Calc Base or Calc Ratios to compute the channel dimensions.The Standard Parameters are used in drawing the channel detail. When OK is selected, the routineends and the channel is drawn if Draw Channel Detail is checked.

When choosing Calc Base or Calc Ratios, there will be a message Error: unable to solve theseparameters on the top line if the design parameters never reach erosion conditions for any channel


Pipe Culvert Design

FunctionThe pipe culvert routine reports discharge and velocity for any pipe flow depth. Fixed inputsinclude diameter of pipe, pipe length, slope and Manning's n value. The operative variable isdepth of flow. This can be entered in the dialog box at lower left and the solution is obtained byclicking Solve or by pressing enter with the Depth of Flow box clicked.

PromptsWhen entering the fixed inputs under Culvert Design Input Parameters, the best approach is to workfrom the Manning's n for Pipe up to the Embankment Elevation (bottom-to-top). The main reasonfor this is that Depth of Flow at the lower left is solved by subtracting Maximum Water Elevationminus Inlet Elevation, which leads to large depths if Maximum Water Elevation is entered first ina top-to-bottom sequence. The Manning's n may be selected from a table of pipe values. Whenthe Manning's n is selected, the type of pipe is shown at the lower right. The Embankment Elevationrefers to the top of the road, or the elevation above which the water backed up behind the pipe wouldoverflow. Clearly, one goal in culvert design is to size the pipe such that the peak water flow willnot overflow the Embankment Elevation. Another design goal might be to prevent the dischargevelocity from exceeding a certain speed (such as 5 fps), to protect against erosion. The user canaccomplish these design goals by altering pipe slope, pipe diameter and depth of flow in particular.

Type of Pipe Flow

Three types of flow are considered: (1) Open Channel, valid for depths up to 94% full, (2) Orifice(inlet) Control and (3) Pipe Control.

Open Channel FlowClick Open Channel at right and enter a depth less than full flow and the program will calculatevelocity and discharge. If a depth is entered greater than full, the program will report 0 velocity anddischarge, indicating open channel flow does not apply. The above dialog box shows calculateddischarge and velocity for a depth of flow of 1.2 feet in a 24 inch pipe.

dimension. Consider an extreme error case with a discharge of 1 cfs, a slope of 0.1%, and a velocityof 5.0 fps. There are no dimensions that meet these requirements. So, for this case, the channeldimensions can be set anyway to avoid erosion.


Prerequisite: None.

Keyboard Command: channel2

File Names: \lsp\chan_erd.lsp & \lsp\hydro.dcl


Orifice (Inlet) ControlClick on Orifice Control and enter any depth greater than 1/2 of the diameter to calculate velocityand discharge. Orifice control does not consider the values for the Inlet Head Loss Coefficient.

Pipe ControlClick on Pipe Control and obtain velocity and depths for pipes flowing full or above full. Thecalculations are affected by the Entrance Loss Coefficient, which can be selected by picking oneof the types in the upper right, or directly entered.

It will generally be noted that at greater depths at the inlet and lesser pipe slopes, the pipe controlwill tend to give lower discharge results than the orifice control. The user should accept the valuewhich is the lesser of the two. Thus in the case shown in the above dialog, pipe control governs,using an entrance loss coefficient of 0.78.


Other Pipe ConditionsBesides standard open channel, orifice control and pipe control, there are other conditions notdirectly considered in the calculations. For example, when the outlet of the pipe is submerged ina pond, it is considered to have "tailwater". Pipes emptying out on a hillside have no tailwater, andthe value should remain 0. If the user enters a tailwater, this will appear on the standard detail ifselected. However, the affect of tailwater is not at present factored into the calculations. Also,subtle flow affects in the near full condition are also ignored, as open channel flow passes into orificeand pipe control.

Output Options

Write ReportIf this box is clicked, upon exit of the dialog box (after clicking OK), the program will present a reportscreen and provide the option of printing, drawing the report in AutoCad or storing the report toa file.

Write Sedcad FileThis option produces a file with a .CVT extension that can be used as one of the building blocksfor the SedCad program (a third party hydrology and sedimentology stand-alone softwarepackage). The file is identical to what is produced within SedCad by its utilities program. The filefor the above pipe control example appears as follows: 37 0.78 80.0 1.25 0.024 4.5 0.0


Draw Pipe DetailWhen clicked, this will produce a fully annotated standard detail, with user-controlled inlet andoutlet stope entries and scaling. The detail is shown below with the results of Write Report.

Write Stage/Discharge FileThis will produce a file of flow for increasing depths at the inlet. It is useful for computing ponddepths at increasing flows. The file is used by the Hydrograph Development program within theWatershed pulldown, which tracks flow through a watershed passing through structures, usingthe SCS TR20 program. The stage/discharge file has a .STG extension.


Prerequisite: None.

Keyboard Command: culvert

File Names: \lsp\culvert.lsp


Report from the Read Profile option

Profile ReportSewer ProfileStation Invert-IN Invert-OUTDistance Slope Width(in) Depth(in) Time(min) Velocity(fps)0+40.44 61.80 61.80285.53 2.50% 10.00 1.51 2.21 2.153+25.88 68.94 68.94274.20 2.40% 10.00 1.53 2.16 2.126+00.00 75.52 75.52200.02 1.50% 10.00 1.71 1.86 1.808+00.00 78.52 78.52

Flow rate: 50.0 (GPM)Manning’s n for pipe: 0.020Total travel time: 6.23 (min)

Dialog for the Individual method

Sewer Pipe Design

FunctionThis command calculates the travel time, flow depth, and velocity for a section of pipe. TheIndividual option cal-culates for one pipesection using the dia-log shown below.The Read Profile op-tion reads the sta-tions and elevationof a sewer or pipeprofile (*.pro) cre-ated by the DesignSewer/Pipe Profilecommand in the Sec-tion-Profile module

Pull-Down Menu Loca-tion: Structure

Prerequisite: None.

Keyboard Command:swrpipeFile Names:\lsp\swrpipe.lsp


Lift Station Design

FunctionThis command aids in the design of duplex sanitary or storm sewage lift stations. The programassumes a duplex station, with the second pump used solely fro backup. That is, there are noprovisions for multiple pump operation. The system head curve and pump curve are calculatedusing the least squares method of curve fitting through three points. To calculate the three pointsinput the length of the force main (length of pressurized pipe), an assumed low-level wastewatersurface elevation in the wet well, the elevation of the static lift in the force main, the sum of minorloss coefficients in the force main , and three flowrates that adequately cover the desired range ofpump operation. The total dynamic head is calculated for each of the three flowrates by adding thestatic head, friction losses, velocity head, and minor losses that are calculated by the program fromthe input data. The next step is the calculation of the pump curve. The user should select one ormore pumps from a manufacturer's catalog that will produce the desired operating conditions. Theinput data consists of the pump shutoff head (flow rate equal to zero), a head and flowrate near thedesired operating point , and a head and flowrate beyond said operating point of the pump curve.


The system head curve and the pump curve are then intersected to produce preliminary operatingpoint results. If the user is not happy with the results, click the Edit Input Values button and changeany of the parameters. When the user attains the desired results then proceed with the wet welldesign by clicking OK.

Input for the wet well design includes type of wet well, wet well dimensions, invert elevation of thelowest line entering the wet well, and minimum wastewater depth in the wet well (usually specifiedby the pump maker). The lead pump's wet well volume is calculated using a formula from Metcalf& Eddy's Wastewater Engineering: Collection and Pumping of Wastewater: V = CT/4where V equals required volume in gallons, C equals pump capacity (GPM), and T equals minimumtime in minutes of one pumping cycle. After wet well design the program assigns a new low levelwastewater surface elevation in the wet well, and then recalculates the system head curve and finaloperating point. At this point the user may change any or all of the input parameters. If no changesare needed then click OK to show the Final Results report.


Prerequisite: None.

Keyboard Command: LIFTSTA

File Names: \lsp\liftstat.lsp & \lsp\liftstat.dcl


Set Sewer File

FunctionThis command sets a sewer network file as the current file. The other sewer network commands willreference this file. Either a new file can be created or an existing sewer file can be modified. The sewernetwork file stores all the sewer structure data (elevation, flow) and all the network connection data(slopes, pipe sizes). This file has a .sew file extension.

Keyboard Command: setswr

Pull-down Menu Location: Structure within Hydrology Menu

Prerequisite: None

File Names: \lsp\pswrfile.lsp

Locate Sewer Structure

FunctionThis command adds a manhole to the sewer network. The location of the manhole can be placedeither by picking the location, specifying a point number or by station and offset from a centerline.A surface model is required to calculate the default rim elevation and the minimum cover of any pipeconnections. The surface model can be a grid file or triangulation file created by the Make 3D GridFile or Triangulate & Contour commands.

Once the manhole location is set, the Sewer Structure Data dialog appears for setting the manholeparameters.

To change the manhole position, pick the Change Location button which allows you to pick themanhole location.

The Structure and System Names identity this manhole. Each manhole in the network must havea unique name.

The Symbol Number specifies the symbol to draw for this manhole. The size of the symbol isdetermined by the Horizontal Scale and Symbol Size in the Drawing Setup command.

Invert Elevation IN is the bottom elevation at the manhole inflow. Each upstream connection hasa separate invert in elevation.

Invert Elevation OUT is the bottom elevation at the outflow.


Rim Elevation is the surface elevation.

Depth is the elevation difference from the Rim Elevation to the Invert Elevation IN.

Area specifies the drainage area that flows into this manhole. The area units can be either squarefeet, square miles or acres. The Select Area button allows you to select a closed polyline that theprogram will calculate the area from.

Time to Inlet is the time of concentration in minutes for this drainage area.

Intensity is the Inches per Hour rainfall intensity to be used with the rational method.

Runoff Coefficient is the rational method number. Given the Time to Inlet, Intensity and RunoffCoefficient the program will calculate the flow into the manhole (Q) using the rational method.

Upstream Connections shows a list of the upstream manholes that this manhole is directly


Edit Sewer Structure

FunctionThis command brings up the Sewer Structure Data dialog for the selected manhole. To select amanhole, pick on the manhole symbol. Any of the data in this dialog can be modified.

PromptsSurface Model to Read Chose a grid or triangulation fileSelect sewer structure to edit: pick a manhole symbolSewer Structure Data dialogSelect sewer structure to edit: Press Enter to End

Keyboard Command: editswr


Prerequisite: Sewer network manholes

File Names: \lsp\makegrid.arx

connected to by a pipe. There is no need to specify downstream connections because the programautomatically figures the downstream connections based on the upstream connections. The listof manholes in the network is displayed in the Available list. To add a pipe connection to thismanhole, highlight a manhole from the Available list and pick the Add button. To remove aconnection, highlight the manhole from the Upstream Connections list and pick the Remove button.

For each connection, the pipe size, slope percent and manning's n can be set. First choose a manholefrom the Upstream Connections list to specify which connection to edit. The slope percent isautomatically calculated from the Invert In of the current manhole and the Invert Out of the upstreammanhole. Entering a new slope percent will adjust the elevation of the current manhole. TheMinimum Cover reports the minimum depth from surface along the pipe. The Area In reports thetotal drainage area from the upstream manhole and Q in reports in flow from the upstream manhole.

PromptsSurface Model to Read Chose a grid or triangulation fileLocate by pick point, point number or station-offset (<Pick>/Number/CL)? Press EnterPick manhole location: pick a pointSewer Structure Data dialogPick manhole location: Press Enter to end

Keyboard Command: editswr


Prerequisite: A surface grid file



Draw Sewer Network

FunctionThis command draws and labels the manhole symbols and pipe connections for the current sewernetwork file. An arrow is drawn on the connections to indicate the direction of flow.

Keyboard Command:drawswrPull-down Menu Loca-tion: Structure within Hydrol-ogy MenuPrerequisite: Sewer networkfile (.sew)File Names:\lsp\cntr_grd.arx

Remove Sewer Structure

FunctionThis command removes a manhole from the sewer network. To select a manhole, pick on the manholesymbol. The manhole symbol and labels are erased from the screen and the manhole is removedfrom the sewer network file.

PromptsSelect sewer structure to remove: pick a manhole symbolSelect sewer structure to remove: Press Enter to end

Keyboard Command: rmswr


Prerequisite: Sewer network manholes

Example drawn sewer network


SpreadSheet Sewer Editor

FunctionThis command is only available in Version 13 for Windows. Excel is also required. This commanddisplays the sewer network data in an Excel spreadsheet. The spreadsheet is filled out using thedata in the current sewer network file (.sew file). Any of the data values can be edited in thespreadsheet and saved back to the sewer file. For example, you can change the pipe sizes or pipeslopes. The only functions that the spreadsheet does not handle are creating new manholes andchanging manhole locations. Manholes can only be placed with the Locate Sewer Manhole routine.

This command will automatically start Excel if Excel is not yet running. Then a new spreadsheet iscreated by filling in a base spreadsheet file with the sewer network data. The base spreadsheet iscalled dde.xls and contains the spreadsheet titles and format. After making changes in thespreadsheet, the changes can be saved back to the sewer file by switching to the SurvCADD screenand pressing Enter where it prompts Press ENTER to update swr file and exit.

The spreadsheet contains two types of rows. One row is for an inlet or manhole and the other isfor a reach or pipe connection. The inlet row includes the inlet name, drainage area, runoffcoefficient, time of concentration, rainfall intensity, rim elevation and depth. The reach rowincludes the inlet names, total drainage area, total time of concentration, total flow (Q), pipesize, in and out invert elevations, reach length and calculated flow values. The formulas for thecalculated flow values are based on the rational method. These formulas are embedded in thespreadsheet cells.

The spreadsheet is filled out in top to bottom order. The drainage area, time of concentration andflow accumulate as the spreadsheet moves down the network.

PromptsChoose Grid FileWrite stage-storage to SEDCAD file (Yes/<No>)? Press Enter

Keyboard Command: editswr2


Prerequisite: Sewer network file (.sew)

File Names: \lsp\cntr_grd.arx, \msoffice\excel\excel.exe, \lsp\ddeads.exe

D e s i g n R E M A R K SFlow depthQ V Q - full V - full TC: MH depth(in) (cfs) (fps) (cfs) (fps) U/S D/S Reach Leng

TC 901.2 4.939.6 1.154079 1.713365 1.180264 1.502758 896.27 896.24 32.05994

TC 901.2 5.069.6 2.184973 3.243848 2.234547 2.845114 896.14 896.1 11.9256

TC 901.4 5.3

10 Yr Storm C a l c u l a t i o n s REACH INLET AREA COEFF. SUM TIME CONC. (min) INTEN. Q=CIA PIPE RCP n= 0.012FROM TO (acres) TOTAL "C" CA CA INLET DRAIN TOTAL "I" (cfs) SIZE V - full depth SLOPE max. V SLOPE

(in) (fps) (in) % (fps) %793 0.32 0.5 0.16 5 5 6.98 1.1168

793 792 0.32 0.16 5 0.311861 5.311861 1.1168 12 1.421954 9.6 0.083643 1.65802 0.093575792 0.18 0.8 0.144 5 5 6.98 1.00512

792 788 0.5 0.304 5.311861 0.061273 5.373134 2.12192 12 2.701712 9.6 0.301951 3.150239 0.335413788 0 0 0 0 0 0 0

survcadd hydrology module - carlson softwarefiles.carlsonsw.com/mirror/manuals/old/hydro.pdf ·...

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