SPS 382.36 Note
Note: For further explanatory material regarding the rational method, other methods and runoff co-efficients, see ch.
SPS 382 Appendix A-382.36 (4).
SPS 382.36(5)(a)(a)
Peak flow. The peak flow of stormwater influent to a plumbing system shall be calculated using any of the following methods:
SPS 382.36(5)(a)1.
1. `Area method.' For sizing of conveyance piping, when calculating stormwater peak flow based on the tributary area, the area in square feet shall be divided by the following applicable divisors:
SPS 382.36(5)(a)1.c.
c. For lawns, parks and similar land surfaces the divisor is 104 square feet/gpm.
SPS 382.36 Note
Note: For example, 10,000 square feet of roof area/26 square feet/gpm = 385 gpm or 0.85 cubic feet/second.
SPS 382.36(5)(a)2.
2. `Rational method.' For calculating peak flow, the intensity shall be determined using the time of concentration for the tributary area.
SPS 382.36 Note
Note: For the equation procedure for runoff coefficients for use with the rational method, refer to ch.
SPS 382 Appendix A-382.36 (5)-1.
SPS 382.36(5)(a)3.
3. `Engineering analysis method.' An engineering analysis shall be based on an analysis provided by a Wisconsin registered architect, registered professional engineer, or permitted designer of engineering systems - plumbing, or an approved alternate standard per s.
SPS 381.20 (2) based on the peak flow calculated in accordance with sub.
(3) (a).
SPS 382.36 Note
Note: A model that calculates peak flow such as SWMM, TR-20, TR-55, P8 or an equivalent methodology may be used.
SPS 382.36(5)(b)
(b)
Volume. The volume of stormwater influent to a plumbing system shall be based on an analysis provided by a Wisconsin registered architect, registered professional engineer, or permitted designer of engineering systems – plumbing, or an approved alternate standard per s.
SPS 381.20 (2) and a minimum of a two-year, 24-hour storm event and designed so that no property damage occurs at 100-year, 24-hour storm event with a Type II distribution.
SPS 382.36 Note
Note: For runoff coefficients and use of other methods or models, refer to ch.
SPS 382 Appendix A-382.36 (5)-2 and
A-382.36 (5)-3.
SPS 382.36 Note
Note: The intensity of rainfall varies considerably during a storm as well as geographic regions. To represent various regions of the United States, the U.S. Department of Agriculture (USDA), Natural Resources Conservation Service (NRCS) developed four synthetic 24-hour rainfall distribution types from available National Weather Service (NWS) duration-frequency data (Hershfield 1961; Frederick et al., 1977) or local storm data. Type IA is the least intense and type II is the most intense short duration rainfall. Types I and IA represent the Pacific maritime climate with wet winters and dry summers. Type III represents Gulf of Mexico and Atlantic coastal areas where tropical storms bring large 24-hour rainfall amounts. Type II represents the rest of the country, including Wisconsin. For more information, see the USDA-NRCS webpage:
http://www.nrcs.usda.gov/.
SPS 382.36(5)(c)
(c)
Additional inputs to stormwater systems. Additional inputs to stormwater systems shall be estimated based on anticipated flows and volumes.
SPS 382.36(6)(a)
(a)
Design. The design of stormwater and clearwater conveyance systems shall conform to all of the following:
SPS 382.36(6)(a)1.
1. Horizontal stormwater conveyance piping shall be sized using either of the following:
SPS 382.36(6)(a)1.a.
a. An engineering analysis, based on full flow capacity, acceptable to the department.
SPS 382.36(6)(a)2.a.a. A vertical conductor for stormwater may not be smaller than the largest horizontal branch discharging into the conductor.
SPS 382.36(6)(a)2.b.
b. Vertical conductors shall be sized in accordance with Tables 382.36-1 and 382.36-3 or by an engineering analysis acceptable to the department.
SPS 382.36 Note
Note: For the use of Baird's equation, refer to ch.
SPS 382 Appendix A-382.36 (6)-1.
SPS 382.36(6)(a)4.
4. Underground, gravity-flow storm building sewers shall have a minimum 3-inch inside diameter.
SPS 382.36(6)(b)
(b)
Velocity in stormwater conveyance system piping. The pitch of stormwater conveyance system piping shall be designed to create a minimum velocity of one foot per second when flowing full.
SPS 382.36(6)(c)2.
2. The minimum radius for the first 90
° fitting located downstream of a roof drain shall comply with the horizontal to vertical requirements in Table 382.30-4.
SPS 382.36(6)(e)1.
1. The minimum pitch of gravity conveyance system piping having a 2-inch inside diameter or less shall be 1/8 inch per foot.
SPS 382.36(6)(e)2.
2. The minimum pitch of clearwater gravity conveyance system piping having at least a 3-inch inside diameter or more shall be 1/16 inch per foot.
SPS 382.36(6)(f)
(f)
Branch connections near base of stack. Branch drains from interior clearwater inlets may not connect downstream from the base fitting or fittings of a drain stack within a distance equal to 20 pipe diameters of the building drain.
SPS 382.36(6)(g)1.1. The storage volume of a dry detention system shall be designed and installed with a drain time of 72 hours after a storm event.
SPS 382.36(6)(g)2.
2. Paved surfaces or parking lots serving as detention areas shall be limited to a design
depth of 6 inches, unless otherwise limited by local ordinance.
SPS 382.36(6)(g)3.
3. By design, ground surface ponding shall drain within 24 hours after a storm event.
SPS 382.36(6)(g)4.
4. A subsurface stormwater detention system that has a permanent pool of water shall be designed and installed in a manner that accomplishes vector control.
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See PDF for table 
SPS 382.36 Note
Note: To convert to cubic feet per second (cfs) divide gpm by 448.8.
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See PDF for table SPS 382.36 Note
Note: To convert to cubic feet per second (cfs) divide gpm by 448.8.
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See PDF for table
a. Sizing per manufacturer's specifications.
SPS 382.36 Note
Note: To convert to cubic feet per second (cfs) divide gpm by 448.8.
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See PDF for table SPS 382.36 Note
Note: To convert to cubic feet per second (cfs) divide gpm by 448.8.
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See PDF for table SPS 382.36(7)(a)1.1. A subsoil drain discharging to a plumbing system shall discharge into an area drain, manhole or storm sewer, trapped receptor or a sump with a pump.
SPS 382.36(7)(a)2.
2. Where a foundation drain is subject to backwater, the drain shall be protected by a backwater valve or a sump with a pump.
SPS 382.36(7)(b)
(b)
Backwater valve. All backwater valves shall be accessible for maintenance.
SPS 382.36(7)(c)1.1. No storm building sewer or private interceptor main storm sewer may pass through or under a building to serve another building, unless one of the following conditions is met:
SPS 382.36(7)(c)1.a.
a. The storm building sewer or private interceptor main storm sewer serves farm buildings or farm houses, or both, that are located on one property.
SPS 382.36(7)(c)1.b.
b. Where a storm building sewer or private interceptor main storm sewer serves buildings that are located on one property, a document that indicates the piping and distribution arrangement for the property and buildings is recorded with the register of deeds no later than 90 days after installation.
SPS 382.36(7)(d)1.1. The connection of a stormwater leader discharging to a storm building sewer shall be made at or above the finished grade.
SPS 382.36 Note
Note: For more information regarding joints and connections, refer to s.
SPS 384.40.
SPS 382.36(7)(d)1m.
1m. If in direct connection and at finished grade, a removable strainer shall protect the inlet. The capacity of the strainer shall be provided in accordance with sub.
(9) (b).
SPS 382.36(7)(d)3.
3. Interior inlets and drains subject to backflow or backwater shall be protected with a check valve or backwater valve.
SPS 382.36(7)(d)8.
8. Storm building drains, clearwater building drains, and building storm sewers and appurtenances shall be separated from water wells by the applicable separation distances contained in chs.
NR 811 and
812, or as otherwise permitted by the department of natural resources.
SPS 382.36(7)(d)9.
9. All underground stormwater storage tanks for water reuse shall be separated from sanitary sewers by a minimum of 8 feet.
SPS 382.36(7)(d)10.a.a. A means to locate buried non-metallic storm building sewers and private interceptor main sewers that discharge to municipal mains shall be provided in accordance with the options under s.
SPS 382.30 (11) (h), except as provided in subd.
10. b. SPS 382.36(7)(d)11.
11. Subsoil drain connections to the storm sewer shall be installed at a point above the horizontal center line of the storm sewer in such a manner that the subsoil drain is entirely above the top of the building sewer; or be provided with a backwater valve.
SPS 382.36(7)(e)
(e)
Hydrodynamic stormwater separators. Hydrodynamic stormwater separators shall conform to ASTM F1745/F1745m.
SPS 382.36(8)(a)1.1. `General.' All storm building subdrains shall discharge into a sump, the contents of which shall be automatically lifted and discharged, dispersed or used in accordance with sub.
(4).
SPS 382.36(8)(a)2.a.a. Except as provided in subd.
2. c. and
d., an interior sump shall have a rim extending at least one inch above the floor immediately adjacent to the sump.
SPS 382.36(8)(a)2.b.
b. A sump shall have a removable cover of sufficient strength for anticipated loads.
SPS 382.36(8)(a)2.c.
c. Where a sump is installed in an exterior meter pit or elevator pit, the rim may be level with the floor.
SPS 382.36(8)(a)3.
3. `Location'. All sumps installed for the purpose of receiving clearwater, groundwater or stormwater shall be separated from water wells by the applicable separation distances contained in chs.
NR 811 and
812, or as otherwise permitted by the department of natural resources.
SPS 382.36(8)(a)4.a.a. Except as permitted under subd.
4. b. or
c. the size of each sump shall be no smaller than 16 inches in diameter at the top, 14 inches in diameter at the bottom, and 22 inches in depth, but in no case smaller than the manufacturer requirements to ensure sufficient pump run time.
SPS 382.36(8)(a)4.b.
b. The minimum sump diameter may be smaller than 16 inches when specified by the manufacturer for a combination sump and pump.
SPS 382.36(8)(a)4.c.
c. A sump located in an elevator pit may have a width or diameter of not less than 12 inches and a depth of not less than 12 inches.
SPS 382.36(8)(a)5.
5. `Solid covered sumps.' A storm or clearwater sump with a solid cover shall be vented. The vent shall terminate a minimum of 1 inch above finished floor and be sized per Table 382.31-4. In lieu of a separate vent, a sealed sump may incorporate a radon vent connected to the subsoil drain or sump cover.
