United States Department of Agriculture 570-CPS-1

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NRCS reviews and periodically updates conservation practice standards. To obtain the current 

version of this standard, contact your Natural Resources Conservation Service State office or 

visit the Field Office Technical Guide online by going to the NRCS website at 

https://www.nrcs.usda.gov/ and type FOTG in the search field. 

USDA is an equal opportunity provider, employer, and lender.

Natural Resources Conservation Service 

CONSERVATION PRACTICE STANDARD 

STORMWATER RUNOFF CONTROL 

CODE 570 

(ac)

DEFINITION 

Measures or systems to control the quantity and quality of stormwater runoff. 

PURPOSE 

This practice is used to accomplish one or more of the following purposes in controlling stormwater runoff: 

• Minimize erosion and sedimentation during and following construction activities 

• Reduce the quantity of stormwater leaving developing or developed sites 

• Improve the quality of stormwater leaving developing or developed sites 

CONDITIONS WHERE PRACTICE APPLIES 

This practice applies to sites where stormwater runoff causes or may cause undesirable downstream

conditions such as flooding due to increased flows, sedimentation, channel degradation, and/or

degradation of surface or ground water quality if left untreated. This practice may apply both to sites

undergoing development as well as remedial work on developed sites. This practice does not include

runoff from areas of livestock facilities. For runoff from livestock facilities use practices such as NRCS

Conservation Practice Standards (CPSs) Waste Storage Facility (Code 313) and Vegetated Treatment

Area (Code 635). 

CRITERIA 

General Criteria Applicable to All Purposes 

Plan, design, and construct stormwater runoff controls to comply with applicable Federal, State, and local

laws and regulations, including all necessary permits and utility locations. 

Develop a plan to reduce the impacts of stormwater runoff from the site based on an assessment of the

downstream area. As applicable, include in the plan practices or management activities that will— 

• Reduce onsite erosion. 

• Reduce offsite impacts from sedimentation. 

• Reduce the quantity of stormwater leaving the site to levels that will not adversely affect

downstream receiving channels. 

• Maintain or increase infiltration of precipitation to recharge ground water. 

• Improve the quality of runoff leaving the site. 

• Leave the site in a stable condition after construction. 

All runoff control methods must include provisions to safely bypass runoff in excess of the design storm. 
Stabilization measures 

Where appropriate, stabilize all areas disturbed by construction as soon as possible after construction to

reduce the potential for erosion. When vegetation is used, refer to NRCS CPSs Critical Area Planting

(Code 342) or Conservation Cover (Code 327). If vegetation is not appropriate for the site, use other

measures such as NRCS CPS Mulching (Code 484) that protect the soil from erosion. Include

pretreatment measures in the system as necessary to protect plantings from excessive sediment, trash,

debris, or other pollutants. 

Safety 

Detention ponds and other areas where water is detained or flows swiftly can present hazards to the

public. Where necessary, include appropriate safety features to warn of potential dangers or deter entry to

hazardous areas such as with fences, gates, and warning signs. 

Additional Criteria for the Reduction of Water Quantity 

Design stormwater control systems to control flow from the area of concern to rates and volumes that will

not cause degradation of downstream areas due to erosion or sedimentation. Acceptable peak rates and

volumes are dependent upon the capacity and stability of the receiving channel. Refer to local regulations

that specify acceptable discharge rates and volumes for different storm frequencies. In the absence of

local requirements, use the 2-year 24-hour predevelopment storm for the peak discharge rate and volume

to receiving streams. 

Control the peak rate of runoff by slowing the release of runoff from the site. This can be accomplished by

onsite storage, increasing infiltration onsite, lengthening the flow path of runoff, or a combination of these

methods. Use one or more of these methods to reduce peak rates of runoff. 

All runoff control methods must include provisions to safely bypass runoff in excess of the design storm. 

Additional Criteria for the Improvement of Water Quality 

Runoff from developing areas, including farmsteads, access roads, and storage areas, can be

contaminated with a variety of substances including sediment, oils, chemicals, and trash. Assess site

conditions to determine the type of contaminants that must be controlled. Design practices that will

capture or reduce these contaminants before they leave the site. These can include diversion of clean

water, vegetated filtration areas, rain gardens and other biofilters, management actions to prevent spills of

fuels or other contaminants, and trash guards and settling areas that are readily accessible for cleanout.

Provide a minimum of 2 feet of soil depth from bedrock to the bottom of impoundments, vegetated

filtration areas, rain gardens, and other biofilters. 

Additional Criteria for Erosion and Sediment Control 

Control erosion on the site by limiting the amount and length of time that bare soil is exposed to

precipitation. This can be accomplished by staging construction and only removing vegetation from a

portion of the site at a time, revegetating areas incrementally during construction or using temporary

seeding and mulching to stabilize areas until permanent vegetation can be established. 

Structural erosion control practices that reduce overland flow length and velocity such as NRCS CPSs

Diversion (Code 362) and Terrace (Code 600), straw bale barriers, or silt fences can be used to reduce

sheet and rill erosion. Refer to the current NRCS soil loss prediction methodology to determine the

appropriate spacing for these practices. 

When erosion cannot be stopped at the source, filter or detain sediment-laden runoff to allow sediment

particles to settle out to acceptable levels before releasing runoff from the site. This can be accomplished

by sediment traps, sediment basins, and other structures designed to detain or filter runoff. Refer to NRCS

CPS Sediment Basin (Code 350) for design requirements for sediment basins. 

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CONSIDERATIONS 

Research has shown that the first runoff from a site is often the most contaminated. After this initial flush,

less pollutants are available for removal, and dilution lessens the impact. Consequently, treatment of this

“first flush” of runoff is often sufficient to address the water quality concern. The exact amount of runoff to

treat varies depending upon the surface and level of contamination. Determine the amount of runoff to

treat based on appropriate research or experience. 

For runoff that is known to be contaminated with substances that may be particularly harmful to the water

supply or fish and wildlife, additional treatment methods may be necessary. 

Stormwater control practices can affect downstream hydrology. While this is the point of most stormwater

control systems, consider the effect (both positive and negative) of changing the peak rate and volume of

runoff on downstream areas. Where there are multiple projects in a watershed, consider the effect of a

single project in context with other projects in the watershed to determine the cumulative effect. For

developed areas consider options for reducing the peak flow from the current developed condition. 

Design stormwater control practices that will fit into the visual landscape as well as function for runoff

control. Since stormwater control practices are generally installed in public spaces, consider the use of the

space and the visual impact the practices will have. 

Improving or maintaining infiltration can be an important component of controlling stormwater runoff. Base

the design of infiltration measures on the permeability rate of the most restrictive layer in the soil profile

within the infiltration zone. Generally, soils should have a saturated hydraulic conductivity rate greater than

0.2 inches per hour. Design storage measures such as dry wells, stone trenches, and basins to empty

within 72 hours. 

If properly designed, stormwater control practices can be beneficial to wildlife. When possible use native

vegetation to provide food and habitat for wildlife and pollinators. 

To be most effective, stormwater control should include a system of practices working together. This might

include detention along with infiltration areas and the maintenance of natural, undisturbed areas.

However, it can also include managing the development of the site to limit the amount of disturbed area,

ensuring that revegetation occurs in a timely manner and controlling where heavy equipment that will

compact soils and destroy vegetation is allowed to travel on a site. 

Large storms can quickly fill stormwater runoff practices with sediment. For the practices to function

correctly the sediment must be removed and properly disposed of. Consequently, design these practices

for easy access and maintenance. 

Since stormwater control practices are often installed in urban and public spaces, vandalism may be a

problem. Consider using practices that cannot be easily vandalized such as grouting rock in place and

installing barriers and locks where appropriate. 

Stormwater runoff control plans are often required by local regulations. As a result, the practices will often

be part of a larger construction contract. To ensure that the plans will be properly implemented it is helpful

to incorporate the requirements of the stormwater runoff control plan into the plans and specifications for

the larger project. 

PLANS AND SPECIFICATIONS 

Prepare plans and specifications for stormwater runoff control systems that describe the requirements for

applying the practice according to this standard. As a minimum the plans and specifications shall

include— 

• A plan view showing the extent of the practice. 

• Where appropriate, cross-sections and/or profiles showing elevations and distances. 

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• Where appropriate, plans for structural details. 

• Where appropriate, seeding requirements. 

• Construction specifications that describe in writing site-specific installation requirements for the

stormwater runoff control systems. 

OPERATION AND MAINTENANCE 

Prepare an operation and maintenance (O&M) plan for the operator. The minimum requirements to be

addressed in the O&M plan are— 

• Periodic inspections, especially immediately following significant rainfall events. 

• Prompt repair or replacement of damaged components, especially surfaces that are subjected to

wear or erosion. 

• Regular inspection of settling basins, trash guards, and other practices to collect and remove

accumulated sediment and debris. 

• Periodic mowing, fertilization, and control of vegetation where vegetation is specified. 

REFERENCES 

Bannerman, R. and E. Considine. 2003. Rain Gardens: A How-to Manual for Homeowners. University of

Wisconsin Extension Publication GWQ037 or Wisconsin Department of Natural Resources Publication

PUB-WT-776 2003. Madison, WI. 

U.S. Environmental Protection Agency. 2007. Developing Your Stormwater Pollution Prevention Plan.

Washington, D.C. 

U.S. Environmental Protection Agency. 2004. Stormwater Best Management Practice Design Guide,

Volumes 1, 2, & 3. Washington, D.C. 

U.S. Environmental Protection Agency. 1999. Stormwater Technology Fact Sheet: Bioretention. Publ.

EPA-832-F-99-012. Office of Water, Washington, D.C.

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