Nebraska Department of Transportation (NDOT)

Drainage Design and Erosion Control Manual, Chapter Three: Stormwater Treatment

StateNebraskahighNo

Fields not found in document: design_criteria.required_hydrologic_hydraulic_software

Other manuals in Nebraska: City of Beatrice, Nebraska

Document Metadata

Jurisdiction level

state

“The NDOT is a regulated MS4 and is required to meet the conditions of its National Pollutant Discharge Elimination System (NPDES) MS4 permit.”
Page 3-4, Section 2.A

State

Nebraska

“Nebraska Department of Transportation (NDOT)”
Page 3-1

Version / edition

April 2018 (dated April 20, 2018); replaces September 2013 chapter

“The information contained in Chapter Three: Stormwater Treatment, dated April 20, 2018... This chapter replaces Chapter Three: Stormwater Treatment, dated September 2013.”
Page 3-1

Adoption / effective date

2018-04-20

“Chapter Three: Stormwater Treatment, dated April 20, 2018... The Nebraska Division of the FHWA approved this chapter for use on the National Highway System”
Page 3-1

Last revised date

2018-04-20

“Chapter Three: Stormwater Treatment, dated April 20, 2018”
Page 3-1

Relationship to state manual

independent

“The NDOT's stormwater treatment program does not supersede a LPA's stormwater treatment program or act as a minimum standard, except when a LPA project is being constructed”
Page 3-4

Design Criteria

Design storm return periods (years)

2-year, 10-year, 100-year

“Chapter One is used to define and direct the peak discharges of stormwater runoff during the highway Design Storms (2-year to 100-year storm events).”
Page 3-26, Section 7.A.7

Water quality volume method

WQV is the first 1/2 inch of runoff from the Treatment Drainage Area (new pavement), WQV = 0.5 in × area (ft²) / 12. Target is ≥80% average annual TSS load reduction. Alternatively size to the WQV Discharge Rate: peak from a 0.75-inch, 24-hour rainfall using the NRCS Curve Number procedure (CN=98 pavement, Tc=5 min; Weighted Q preferred for mixed cover).

“The NDOT has determined that the WQV is the first one-half (½) inch of runoff from the Treatment Drainage Area... WQV = 0.5 inch x Treatment Drainage Area (ft2) /12”
Page 3-17, Section 6.A

Peak flow calculation method(s)

NRCS Curve Number (CN) procedure, Weighted Q method of the CN procedure

“To determine a WQV peak discharge for drainage areas greater than 5 acres, the NRCS CN procedure must be used. The designer can either assume the entire area is pavement with a CN value of 98 or use the weighted Q method of the CN procedure.”
Page 3-18, Section 6.B

Required hydrologic/hydraulic software

Not found in document

No evidence cited

Approved BMP categories

Vegetated Filter Strips, Grass Swales, Infiltration Trench, Infiltration Basin, Bioretention, Media Filter, Extended Dry Detention, Wet Detention Pond, Stormwater Wetland, Pervious Pavement, Proprietary Structural Treatment Control, Other Reasonable Practices

“Storage practices such as extended-detention ponds... Filtration practices such as filter strips... Grassed swales... Bio-retention... Sand filters and... Infiltration practices such as infiltration basins and infiltration trenches”
Page 3-3, Section 1