Drainage (Wisconsin and Iowa Manual) CE550 Xudong Chai March 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 )

Legal Aspects Common Drainage Law – Common enemy rule – Reasonable use rule Statutory Drainage Law (Wisconsin Statutes) – Section – Section – Section – Section (Procedure )

General Guidelines Water Accumulation (Wisconsin Statutes, Section 88.87) Coordinate with Local Drainage Board (Procedure ) DOT and DNR Cooperative Agreement (Procedure ) 401 and 404 Permits (Procedure ) – 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 ) – On collectors and local roads

General Guidelines Overflow Section (Procedure ) – 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 , 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 ) 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 , 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 ) – 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 Figure 1)

Hydrology Design Discharge (Procedure ) – 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 ) – 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 , 4A-4 ) Q=CIA (Urban or potential urban < 5 square mile, Rural < 200 acres) Where: Q = peak runoff rate (cfs) C = runoff coefficient I = intensity of rainfall for a duration equal to the time of concentration (inches per hour) A = drainage area (acres )

Hydrology Design Discharge ( Procedure ) – NRCS, Hydrology for Small Watersheds (Software TR-55 can be downloaded from the following site: 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 ) – USGS flood frequency equations for Wisconsin For example, the equation of the 100-year flood (Q100) for the urban gaging station , 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 ) – 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 ) – 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 ) – 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 ) – 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 ) – 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 ) – 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 ) – 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 ) – 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 ) – 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 ) – 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 ) – 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 ) – 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 ) – Drainage Disposal By Pumping – Siphons and Sag (Inverted Siphon) Culverts (Limited use in highway engineering)

Erosion Water Pollution Control Special Hydraulic Structures ( Procedure ) – Flow Control Gates Flap gates Sluice gates

Erosion Water Pollution Control Special Hydraulic Structures ( Procedure ) – 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 ) – 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 ) – 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 ) – 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 ) – 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)

Underdrains ( Procedure ) – Locations Sidehill Seepage Interception Water Table Drains Surface Leakage Drainage of Granular Bases Laterals and Outlets

Subgrade Drainage (Cont’d) Underdrains ( Procedure ) – 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 ( ) – USGS flood frequency equations for Wisconsin ( )

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 for partially full pipe – Check for major storm – Pressure flow design