Wisconsin Administrative Code
Department of Natural Resources
NR 100-199 - Environmental Protection General
Chapter NR 151 - Runoff Management
Subchapter III - Non-Agricultural Performance Standards
Section NR 151.123 - Peak discharge performance standard

Universal Citation: WI Admin Code ยง NR 151.123

Current through August 26, 2024

(1) REQUIREMENT. By design, BMPs shall be employed to maintain or reduce the 1-year, 24-hour and the 2-year, 24-hour post-construction peak runoff discharge rates to the 1-year, 24-hour and the 2-year, 24-hour pre-development peak runoff discharge rates respectively, or to the maximum extent practicable. The runoff curve numbers in Table 2. shall be used to represent the actual pre-development condition.

Table 2. Maximum Pre-Development Runoff Curve Numbers

Runoff Curve Number

Hydrologic Soil Group

A

B

C

D

Woodland

30

55

70

77

Grassland

39

61

71

78

Cropland

55

69

78

83

Note: Where the pre-development condition is a combination of woodland, grassland, or cropland, the runoff curve number should be pro-rated by area.

(2) EXEMPTIONS. This section does not apply to the following:

(a) A post-construction site where the discharge is directly into a lake over 5,000 acres or a stream or river segment draining more than 500 square miles.

(b) Except as provided under s. NR 151.121(5), a redevelopment post-construction site.

(c) An in-fill development area of less than 5 acres.

The intent of s. NR 151.123 is to minimize streambank and shoreline erosion under bank-full conditions.

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