FLOOD04935

• County: Statewide
• Basin: Statewide
• Title: Storm Water Management for Constructed Activities
• Date: 9/1/1992
• Prepared By: EPA
• Floodplain - Doc Type: Educational/Technical/Reference Information

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Chapter 2-Storm Water Pollution PrevtHItion Plan

Runoff Water Quality

Collect any information on the quality of the runoff from the site which may be available. In many
cases, there will be little water quality data from runoff collected specifically from a site, however,
if your construction site is located on or next to an existing industrial facility, or if it drains to a
municipal separate storm sewer in a city/county with a population greater than 100,000, water
quality data may have been collected which indicates the quality of runoff from your site. Contact
either the industrial facility or the municipal storm sewer authority which will receive your storm
water and ask if they have performed any analysis on storm water from your proposed construction
site. You may also be able to obtain runoff water quality information from the U.S. Geological
Survey (USGS). the USDA Soil Conservation Service (SCS), State or local watershed protection
agencies. Contact these agencies to see if they have collected samples of runoff from your site or
from locations down stream of your site.

Name of Receiving Water

Identify the name of the body of water(s) which will receive runoff from the construction site. If
the receiving water is a tributary include the name of the ultimate body of water if possible.
Receiving waters could include; rivers, lakes, streams, creeks, runs, estuaries, wetlands, bays,
ocean, etc. If the site drains into a Municipal Separate Storm Sewer System, identify the system
and indicate receiving water to which the system discharges. This information is usually available
from county, State, or USGS maps.

Rainfall Data

It is useful to determine the amount of rainfall you will anticipate in your design of storm water
management measures. These rainfall amounts are often referred to as "design storms." Design
storms are typically described in terms of the average amount of time that passes before that
amount of rain falls again and by the duration of the rain (e.g., the 10 year-24 hour storm).
Contact your State/local storm water program agency for additional information on the design
storm criteria in your project area. Consult Appendix G for sources of design storm data if it is not
available from your State/local agency.

2.1.2 Develop Site Plan

The next step in the process is to develop a preliminary site plan for the facility which is to be
constructed. The site plan will be developed primarily based upon the goals and objectives of the
proposed facility. However, there are several pollution prevention principals which should be
considered when developing the site plan for the project. They are:

. Disturb the smallest vegetated area possible.

. Keep the amount of cut and fill to a minimum.

. Limit impacts to sensitive areas such as:

Steep and/or unstable slopes
Surface waters, including wetlands
Areas with erodible soils
Existing drainage channels.

In addition to reducing pollution in storm water runoff from your site, incorporating the above
objectives into the site plan for the project can also: reduce construction costs for grading and

September 1992

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