drainage (wisconsin and iowa manual) ce550 xudong chai march 31, 2005
TRANSCRIPT
Drainage(Wisconsin and Iowa Manual)
CE550
Xudong ChaiMarch 31, 2005
Objectives
Legal Aspects General Guidelines Data Collection and Field Work Hydrology Hydraulic Design of Culverts Erosion Water Pollution Control Subgrade Drainage
Legal Aspects
Three Major Considerations – The safety of the traveling public– The use of sound engineering practices to
economically protect and drain the highway– The protection of private property from flooding,
water-soaking, or other damage.
(Procedure 13-1-1)
Legal Aspects
Common Drainage Law – Common enemy rule– Reasonable use rule
Statutory Drainage Law (Wisconsin Statutes)– Section 88.87– Section 86.075– Section 146.13– Section 236.13
(Procedure 13-1-1)
General Guidelines
Water Accumulation (Wisconsin Statutes, Section 88.87) Coordinate with Local Drainage Board (Procedure 5-15-1) DOT and DNR Cooperative Agreement (Procedure 20-30-1) 401 and 404 Permits (Procedure 21-30-1)
– Discharge of fill (usually upland soil, sand, gravel, riprap) into Waters of the U.S. requires a 404 permit from Army Corps of Engineers
– 401 permit (Water quality certifications) from DNR
Work with Local Sewerage Commissions Consider Fish Passage Determine Drainage Patterns
– Reconstruction and Relocation of a Highway
General Guidelines
Work with Local Sewerage Commissions
General Guidelines
Consider Fish Passage Determine Drainage Patterns
– Reconstruction and Relocation of a Highway
Decide Headwater– How high above the inlet elevation of the culvert the water may go
without causing damage to adjacent property or the road itself.
Drainage Rights and Easements Overflow Section (Procedure 13-10-1)
– On collectors and local roads
General Guidelines
Overflow Section (Procedure 13-10-1)– Considering:
Incremental construction costs Probable property damage, including damage to the highway Traffic volumes and the cost of traffic delays Duration and depth of inundation Frequency of occurrence Length of roadway to be flooded Availability of alternate routes, emergency supply, and evacuation routes The potential for loss of life and budgetary constraints
General Guidelines
Maintenance Considerations– Erosion protection– Larger enough culverts– Curbs or berms and downslope pipe or gutters along fills of erodible
material– Wide-enough drainage easements– Debris catches where needed– Corrosion-resistant structures in areas with corrosive soils and waters– Interceptor ditches along the top of cut slopes– Drainage structures should be located, if possible, beyond the clear
zone. Otherwise, provide protective barriers
Data Collection and Field Work
Data Collection (Procedure 13-1-5, see Figure 1)– Aerial Photos (1" = 200' to 1"= 800‘)– USGS quadrangles or similar maps– Watershed characteristics– Stream crossing locations– Climate information– Limiting design factors– Existing structures– History of flooding and obvious problem areas
Data Collection and Field Work
Data Collection ( 4A-1 )– Preliminary Survey provides the basic survey information for
the project including Plan and profile sheets 10 scales (250 scales in metric) and 20 scales (500 scales in
metric) Cross sections Locations and elevations of existing storm sewer Locations of existing utilities Drainage plats and utility plats
Data Collection and Field Work
Data Collection ( 4A-1 )– Photogrammetry provide
Topography maps Quad maps Aerial photos
Data Collection and Field Work
Data Collection ( 4A-1 )– The city may provide
Zoning plans Planning maps Future street and storm sewer plans Drainage studies Plans for existing systems Plans for future construction or replacement of sanitary sewer and
other utilities
Data Collection and Field Work
Data Collection ( 4A-1 )– Army Corps of Engineers may provide
Flood studies Levee construction plans Flood control plans Other information about flood plains and flood control areas
Data Collection and Field Work
Field Review ( 4A-1 )– Finally, the designer should conduct a field review of the
project to become familiar with the area and any special drainage problems that may exist.
Data Collection and Field Work
Field Review– Preliminary Field Review (Procedure 13-5-1)
Existing and past flood condition (page 3)
(high-water elevations for channels, personal interviews,
approximate flow in channels, etc.) Special controls on flood rates(existing swamps, ponded areas, flood control dams, reservoirs, and
lakes, etc.)
Data Collection and Field Work
Field Review– Preliminary Field Review (Procedure 13-5-1, page 2)
Proposed changes to existing conditions– The collection and concentration of water through a structure
under the proposed highway (page 4)– The change of depth of floodwaters immediately above the
proposed highway (page 5) Possible tail-water controls
– Tail-water depth is the depth of water at the outlet of a structure that will affect the flow of water through a structure
– Placing the outlet of the culvert above the maximum highwater elevation
Data Collection and Field Work
Field Review– Final Field Review
After the preliminary field trip is completed and the follow-up design progresses, another field trip will have to be made to confirm that the structure designs proposed for each structure site are appropriate.
Hydrology
Flood Frequency ( Procedure 13-10-1)
– The average interval in years between the actual occurrence of a hydrological event of a given or greater magnitude.
Design Frequencies– A balance between the cost of a drainage facility and
the cost of potential flood damage– The design flood does not overflow the roadway.
Hydrology
-Design Frequency (Procedure 13-10-1 Figure 1)
Hydrology
Design Discharge (Procedure 13-10-5) – Rational Method– NRCS, Urban Hydrology for Small Watersheds (TR-55)– USGS flood frequency equations for Wisconsin– Gaging station– Published watershed studies– Field review notes, interviews, and historic data
(Compute runoff by at least two of these methods, and the results may be averaged or weighted)
Hydrology-Design Discharge
Hydrology
Design Discharge (Procedure 13-10-5) – Rational Method– NRCS, Hydrology for Small Watersheds (TR-55)– USGS flood frequency equations for Wisconsin– Gaging station– Published watershed studies– Field review notes, interviews, and historic data
(Compute runoff by at least two of these methods, and the results may be averaged or weighted)
Hydrology
Design Discharge– Rational Method ( Procedure 13-10-5, 4A-4 )
Q=CIA (Urban or potential urban < 5 square mile, Rural < 200 acres)Where:Q = peak runoff rate (cfs)C = runoff coefficientI = intensity of rainfall for a duration equal to the time of
concentration (inches per hour)
A = drainage area (acres)
Hydrology
Design Discharge ( Procedure 13-10-5) – NRCS, Hydrology for Small Watersheds
(Software TR-55 can be downloaded from the following site:
http://www.wcc.nrcs.usda.gov/hydro/hydro-tools-models.html)
Graphical Peak Discharge method
Where:
= Factor from TR55, Table 2-1
= drainage area (square mile)
= Runoff depth (inches)
= Percent ponding and swampy areas (0 -1.0)
Hydrology
Design Discharge (Procedure 13-10-5) – USGS flood frequency equations for WisconsinFor example, the equation of the 100-year flood (Q100) for the
urban gaging station 05430403, Fisher Creek Tributary at Janesville, Wis., is:
Where, A = drainage area (square miles) I = percentage of total impervious area (0-100%), related to
includes single-family residential, multifamily residential, commercial, industrial, and public facilities.
Hydrology
Design Discharge (Procedure 13-10-5) – Gaging station data (page 7)
In addition to computing discharges by the USGS flood frequency equations, a comparison should be made with steam gaging data from similar drainage basins in the locality.
Hydrology
Design Discharge (Procedure 13-10-5) – Published watershed studies Hydrologic and hydraulic information for a specific watershed may
be obtained from: Regional Planning Agencies Army Corps of Engineers Natural Resources Conservation Service U. S. Geological Survey Consulting Engineering Companies
Hydrology
Design Discharge (Procedure 13-10-5) – Field review notes, interviews, and historic data
Field review notes of stream channels and existing structures can indicate high-water elevations that have occurred in the past.
Field interviews of local residents can be very important in determining past flow rates.
Historic flood information of extreme high-water elevations can often be used to make estimates of peak discharges.
Hydrology
Hydrograph (Procedure 13-10-5) – Hydrograph is defined as the graph of flow (rate versus time)
at a stream section.– Hydrographs are used in the planning and design of water
control structures, especially detention basins, which are used to minimize downstream flooding by attenuating the peak flows of storms with specific duration frequencies.
– Hydrographs are also used to show the hydrologic effects of existing or proposed projects.
Hydrology
-Hydrograph
Hydraulic Design of Culverts
Economic Analysis ( Procedure 13-15-1)– Economic design requires that the pipe flow at least
full or with some headwater– Full-flow culverts reduce the size of the culvert, and
therefore reduce the cost– Many effects needs to be considered
Hydraulic Design of Culverts (Cont’d)
Design Criteria ( Procedure 13-15-5)– Culvert Location
(The culvert passes the expected discharge with as little interruption as practical)
– Structure size selection Estimated runoff (Q). Approximate length and slope of culvert. Allowable headwater depth Entrance type. Barrel cross-sectional shape Barrel roughness factor Tail-water conditions
Hydraulic Design of Culverts (Cont’d)
Culvert Hydraulics ( Procedure 13-15-10)– Design Aids
FHWA’s Hydraulic Design Series (HDS) #5 (1) FHWA’s Hydraulic Design Series (HDS) #3 HY8 in FHWA’s HYDRAIN software package
(Any designer should first thoroughly study the above-listed publications)
Hydraulic Design of Culverts (Cont’d)
Culvert Hydraulics ( Procedure 13-15-10)– Inlet-Outlet Control
Two major types of culvert flow– Flow with inlet control– Flow with outlet control
Hydraulic Design of Culverts (Cont’d)
Culvert Hydraulics ( Procedure 13-15-10)– Inlet-Outlet Control
The controlling factors for inlet control:– Inlet Area– Inlet Shape– Inlet Edge Configuration– Allowable Headwater
Hydraulic Design of Culverts (Cont’d)
Culvert Hydraulics ( Procedure 13-15-10)– Inlet-Outlet Control
The controlling factors for outlet control:– Inlet Area– Inlet Shape– Inlet Edge Configuration– Allowable Headwater– Tail Water Elevation– Slope of Culvert– Roughness of Culvert– Length of Culvert– Area of Barrel– Barrel Shape
Hydraulic Design of Culverts (Cont’d)
Culvert Hydraulics ( Procedure 13-15-10)
– Headwater In all culvert design, headwater at the entrance to a culvert is an
important factor in culvert capacity The headwater depth (HW) is the vertical distance from the
culvert invert at the entrance to the energy line of the headwater pool (depth and velocity head)
Assume the water surface and the energy line at the entrance are coincident
• Culvert Hydraulics – Headwater
Hydraulic Design of Culverts (Cont’d)
Culvert Hydraulics ( Procedure 13-15-10)– Improved Inlets
increases the capacity of a given culvert pipe size without raising the headwater
Their use has resulted in considerable savings on various projects throughout the United States
includes bevel-edged, side-tapered, and slope-tapered inlets
Hydraulic Design of Culverts (Cont’d)
Special Hydraulics ( Procedure 13-15-15)– Drainage Disposal By Pumping– Siphons and Sag (Inverted Siphon) Culverts
(Limited use in highway engineering)
Erosion Water Pollution Control
Special Hydraulic Structures ( Procedure 13-35-1)– Flow Control Gates
Flap gates
Sluice gates
Erosion Water Pollution Control
Special Hydraulic Structures ( Procedure 13-35-1)– Debris Control Structures
Can be found in the FHWA publication HEC #9, entitled "Debris Control Structures“
Allow for planned maintenance Allow for emergency maintenance during flood period.
Erosion Water Pollution Control
Detention Basin ( Procedure 13-35-1)– Only for increasing the time of concentration of water flow to any
point of discharge– Not confused with the Retention Basin
Retention basin holds water for infiltration into the subsoil. It is self-draining and after a period of time will be completely free of water
Erosion Water Pollution Control
Temporary Sediment Structures ( Procedure 13-35-1)– Constructed at a suitable location to trap and store sediment– Sediment Trap and Sediment Basin– Formal design information
"Standards and Specifications for Soil Erosion and Sediment Control in Developing Areas," U.S. Department of Agriculture, Soil Conservation Service
"Model Drainage Manual 1991”, AASHTO
Erosion Water Pollution Control
Energy Dissipators ( Procedure 13-35-1)– Warranted when discharge velocities exceed 14 feet per
second– Drop inlets at the inlet– Hydraulic jump at the outlet
Riprap Blanket (Figure 2) Lined Channel Expansions (Figure 3 and 4) Outlet Expansion (Figure 5)
Subgrade Drainage (Cont’d)
Underdrains ( Procedure 13-40-1)– Underdrains or subdrains are installed to control three
specific types of groundwater: (Figure 1) Seepage in cuts or sidehill areas High-water tables Subbase and/or subgrade areas where water enters from
either the surface or below the surface
Subgrade Drainage(Cont’d)
Subgrade Drainage (Cont’d)
Underdrains ( Procedure 13-40-1)– Locations
Sidehill Seepage Interception Water Table Drains Surface Leakage Drainage of Granular Bases Laterals and Outlets
Subgrade Drainage (Cont’d)
Underdrains ( Procedure 13-40-1)– Design Criteria
Size and Length Requirements Separation of Drainage
(Surface drainage discharge into an underdrain – Not permitted)
(The discharge from an underdrain into a roadway drainage system or a culvert – Permissible)
Cleanouts Grade Requirements Depth and Spacing of Underdrains (Figure 2)
Subgrade Drainage (Cont’d) Figure 2
Iowa Urban Drainage Design
Preliminary Roadway Drainage Design (4A-3)– Estimate the locations of intakes and utility accesses– Choose the appropriate accesses to be used– Number all intakes and accesses to facilitate design and
construction
Iowa Urban Drainage Design
Water Discharge Calculation – Rational Method (4A-4)– NRCS, Hydrology for Small Watersheds (13-10-5)– USGS flood frequency equations for Wisconsin (13-10-5)
Iowa Urban Drainage Design
Spread and Intake Location (4A-5)– Spread
Iowa Urban Drainage Design
Sizing Intakes(4A-6)– Intake size: (Intercepting 85% to 90% of the water flowing past the
intake’s location)
– Example:
RA-70 intake, Spread=7ft, Longitudinal grade of gutter = 3%, What percentage of the flow the intake can capture?
Iowa Urban Drainage Design
Pavement Drainage Design (4A-7) Design of Storm Sewer Pipe (4A-8)
– Worksheet 104-5 for partially full pipe– Check for major storm– Pressure flow design