Stormwater Atlas

City of Chesapeake

Stormwater Management and Drainage Design

CityVirginiahighNo
Fields not found in document: document_metadata.adoption_or_effective_date

Document Metadata

Jurisdiction level
municipality

Stormwater, for both water quantity and quality, shall be designed in general by the criteria established herein, the City's Master Drainage Plan

Section 5.0 GENERAL

State
Virginia

the Virginia Department of Transportation Drainage Manual and the Virginia Stormwater Management Handbook

Section 5.0 GENERAL

Version / edition
Revised December 2016

Revised 12/16 STORMWATER MANAGEMENT & DRAINAGE DESIGN

Page headers

Adoption / effective date
Not found in document

No evidence cited

Last revised date
2016-12

Revised 12/16

Page headers

Relationship to state manual
independent

Stormwater, for both water quantity and quality, shall be designed in general by the criteria established herein, the City's Master Drainage Plan, the Virginia Department of Transportation Drainage Manual and the Virginia Stormwater Management Handbook. When there is a conflict between the Virginia Department of Transportation Drainage Manual, the Hampton Roads Planning District Commission Regional Construction Standards and these criteria, these criteria shall govern.

Section 5.0 GENERAL A–B

Design Criteria

Design storm return periods (years)
2-year, 5-year, 10-year, 25-year, 50-year, 100-year

24 Hour Rainfall Depths (NOAA's NWS)... 2-yr. 3.7" 5-yr. 5.0" 10-yr. 6.0" 25-yr. 7.0" 50-yr. 8.17" 100 9.44"

Section 5.2 HYDROLOGY B, Page 5-5

Water quality volume method
Virginia Runoff Reduction Method (VRRM) with DEQ compliance spreadsheets: prevent a net increase in nonpoint source pollution for new development (post-development load shall not exceed predevelopment based on average land cover conditions); for redevelopment, achieve a 10% reduction when land disturbance is less than one acre and a 20% reduction when one acre or greater (Chesapeake Bay Preservation Area Designation and Management Regulations). Non-proprietary BMP pollutant removal efficiencies in Table 4.1 are based upon 1 inch of rainfall.

Virginia's proposed Stormwater Management Program (VSMP) Permit Regulations (4 VAC 50-60 et seq.) include water quality and quantity requirements based, in part, on the "Virginia Runoff Reduction Method" (VRRM).

Section 5.4 B. Water Quality

Peak flow calculation method(s)
Rational method (storm drainage HGL; <200 acres = 10-year, >200 acres = 50-year), NRCS / SCS Type II 24-hour hydrographic methods (basins >200 acres or detention design), NRCS runoff curve number / volumetric runoff coefficients

Storm drainage systems including Hydraulic Grade Line, etc. shall be designed using the rational method, for the recurrence frequency as follows

Section 5.3 HYDRAULICS A.1

Required hydrologic/hydraulic software
HEC-HMS, HEC-GeoHMS, TR-55, TR-20, Pond Pack, WMS / Watershed Modeling, HEC-RAS, EPA SWMM, FHWA HY-8, CulvertMaster, FlowMaster, Virginia Runoff Reduction Method (VRRM) Compliance Spreadsheet, HSPF

Acceptable methods for runoff analysis are tabulated below: Hydrology Software HEC-GeoHMS... HEC-HMS... TR-55... TR-20... Pond Pack... WMS... Watershed Modeling... Hydraulic Software HEC-RAS... EPA SWMM... FHWA HY-8... CulvertMaster... FlowMaster... Water Quality Software VA Runoff Reduction Method... HSPF

Section 5.2 HYDROLOGY C, Pages 5-5–5-6

Approved BMP categories
Rooftop Disconnection, Sheetflow to Vegetated Filter or Conserved Open Space, Grass Channel, Soil Amendments, Vegetated Roof, Rainwater Harvesting, Permeable Pavement, Infiltration, Bioretention / Urban Bioretention, Dry Swale, Wet Swale, Filtering Practice, Constructed Wetland, Wet Pond, Extended Detention Pond, Dry Detention (Virginia Stormwater Management BMP Clearinghouse), Wet Detention (Virginia Stormwater Management BMP Clearinghouse)

Table 4.1. BMP Pollutant Removal Efficiencies... Rooftop Disconnection... Sheetflow to Vegetated Filter or Conserved Open Space... Grass Channel... Soil Amendments... Vegetated Roof... Rainwater Harvesting... Permeable Pavement... Infiltration... Bioretention... Urban Bioretention... Dry Swale... Wet Swale... Filtering Practice... Constructed Wetland... Wet Pond... Extended Detention Pond

Table 4.1, Pages 5-18–5-19