City of Beatrice, Nebraska

Drainage Criteria Manual

CityNebraskahighNo

Other manuals in Nebraska: Nebraska Department of Transportation (NDOT)

Document Metadata

Jurisdiction level

municipality

“This manual applies within the corporate limits of the City and its extraterritorial jurisdiction.”
Page 1, Section 1.1

State

Nebraska

“BEATRICE, NEBRASKA”
Adoption Resolution

Version / edition

August 2020

“Drainage Criteria Manual, dated August 2020”
Adoption Resolution

Adoption / effective date

2020-09-08

“RESOLUTION PASSED AND ADOPTED this 8th day of September, 2020.”
Adoption Resolution

Last revised date

2020-08

“Drainage Criteria Manual, dated August 2020”
Adoption Resolution

Relationship to state manual

independent

“Portions of the City of Lincoln Drainage Criteria Manual, the City of Omaha Regional Stormwater Design Criteria Manual was used in the development of this manual.”
Introduction / related manuals discussion

Design Criteria

Design storm return periods (years)

2-year, 5-year, 10-year, 100-year

“The minor drainage system design will be based on the 5-year (20% annual exceedance probability) design storm for residential areas and the 10-year (10% annual exceedance probability) design storm for”
Section 1.4 / minor drainage system

Water quality volume method

Water Quality Control Volume (WQCV) for sites disturbing ≥1 acre: new development uses the 80th-percentile rainfall event; redevelopment uses the 70th-percentile. Beatrice is Region C (East): P = 0.83 in (80th) / 0.62 in (70th). WQCV = P × (0.05 + 0.009 × %impervious) × treatment drainage area (acres) × (1/12) × 43,560. Flow-based BMPs use Qwq from the NRCS CN procedure on the 80th-percentile 24-hour event with Tc = 5 minutes (impervious area only). WQCV drain-down typically 24–40 hours (up to 72 hours when stacked with flood control).

“For new development sites that have a land disturbance of one acre or greater, the WQCV shall be based on the 80th percentile rainfall event, at a minimum.”
Page 107, Section 9.4.1

Peak flow calculation method(s)

Rational Method, NRCS unit hydrograph / Curve Number method, Modified Rational Method (not for storage facility design)

“Peak runoff values shall be calculated by using either the rational method, NRCS unit hydrograph method, or rational or NRCS methodological software as appropriate.”
Hydrology / peak runoff criteria

Required hydrologic/hydraulic software

HY-8, Hydraulic Toolbox, HEC-RAS, HEC-HMS, Nebraska Department of Transportation Rational Method RMA Calculator

“Software available from the Federal Highway Administration such as HY-8 or Hydraulic Toolbox, the U.S. Army Corps of Engineers such as HEC-RAS or HEC-HMS, or state agencies such as the Nebraska Department of Transportation's Rational Method RMA Calculator are generally acceptable in their most recent versions”
Page 6, Section 1.6 Software

Approved BMP categories

Vegetated Filter Strip, Grass Swale, Infiltration Trench, Infiltration Basin, Bioretention Basin, Media Filter, Sand Filter, Extended Dry Detention, Wet Detention Ponds, Stormwater Wetland, Underground Detention, Pervious Pavement, Proprietary Structural Treatment Controls, Green Roofs, Soil Conditioning, Construction Erosion and Sediment Control BMPs, Good Housekeeping BMPs

“Vegetated Filter Strip... Grass Swale... Infiltration Trench... Infiltration Basin... Bioretention Basin... Media Filter... Sand Filter... Extended Dry Detention... Wet Detention Ponds... Stormwater Wetland... Underground Detention... Pervious Pavement... Proprietary Structural Treatment Controls... Green Roofs... Soil Conditioning”
Page 113, Table 9-3