Wisconsin Department of Natural Resources

Wet Detention Pond (1001) — WDNR Technical Standard

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Narrow WDNR Technical Standard 1001 for wet detention ponds only — not a full statewide stormwater design manual. Explicitly excludes flood-control design; local authorities may require peak control beyond the 2-yr, 24-hour storm. SLAMM/P8/DETPOND are approved optional models, not mandated for every design. Companion standards (1002–1004, 1064) and NR 151 govern broader post-construction requirements.

Fields not found in document: design_criteria.approved_bmp_categories (beyond wet detention pond — this standard covers only one practice)

Document Metadata

Jurisdiction level

state

“This practice provides a method to demonstrate that a wet detention pond achieves the total suspended solids (TSS) reduction and peak flow control required by NR 151.12, Wis. Adm. Code”
Section III

State

Wisconsin

“Wisconsin Department of Natural Resources”
Page 1

Version / edition

10/07

“10/07”
Footer throughout

Adoption / effective date

2007-10

“10/07”
Footer

Last revised date

2007-10

“Technical Standards are reviewed periodically and updated if needed... 10/07”
Page 1 footer note

Relationship to state manual

independent

“Wisconsin Department of Natural Resources Technical Standard”
Page 1

Design Criteria

Design storm return periods (years)

1-year, 2-year, 10-year, 100-year

“the peak outflow during the 1-yr., 24-hour design storm... Design the outlet to control the proposed 2-yr., 24-hour discharge... Any storm up to the 10-yr., 24-hour design storm shall not flow backward... Design the spillway to safely pass peak flows produced by a 100-yr., 24-hour design storm”
Section V.B.1

Water quality volume method

Permanent pool surface area sized from post-construction peak outflow during the 1-yr, 24-hour design storm and target particle settling velocity (Equation 1; 80%/60%/40% TSS via 3/6/12 micron particles). Active storage volume above the permanent pool sized with a hydrograph method (TR-55 / App. B) for the 1-yr, 24-hour storm. Demonstrates TSS reduction and peak-flow control per NR 151.12.

“The permanent pool surface area is sized based on the particle size and the peak outflow during the 1-yr., 24-hour design storm using Equation 1: Sa = 1.2 * (qo / vs)”
Section V.B.1.a.ii

Peak flow calculation method(s)

NRCS Technical Release 55 (TR-55) hydrograph method, Runoff curve numbers (TR-55; cropland Table 1)

“The post-development outflow shall not exceed pre-development peak flows for the 2-yr., 24-hour design storm. Use a hydrograph-producing method such as TR-55 for all runoff and flow calculations.”
Section V.B.1.h.v

Required hydrologic/hydraulic software

SLAMM, P8, DETPOND

“Pollutant loading models such as SLAMM, P8, DETPOND or equivalent methodology may also be used to evaluate the efficiency of the design in reducing TSS.”
Section III

Approved BMP categories

Wet Detention Pond

“Wet Detention Pond (1001)... A permanent pool of water with designed dimensions, inlets, outlets and storage capacity, constructed to collect, detain, treat and release stormwater runoff.”
Section I. Definition