Stormwater Management Practices

Stormwater Management Practices

This section provides some basic information about stormwater management practices and how they work to protect watersheds. For more detailed information, you might want to read the "Why Stormwater Matters" article (.pdf format), or visit our Stormwater Manager's Resource Center at www.stormwatercenter.net.

Stormwater management practices are used to delay, capture, store, treat, or infiltrate stormwater runoff. A watershed manager needs to make careful choices about what stormwater management practices need to be installed in the subwatershed to compensate for the hydrological changes caused by new and existing development.One key choice is to determine the primary stormwater objectives for a subwatershed that will govern the selection, design, and location of stormwater management practices at individual sites. While specific design objectives for stormwater management practices are often unique to each subwatershed, the general goals for stormwater management practices usually include the following:

Maintain groundwater recharge and quality
Reduce stormwater pollutant loads
Protect stream channels
Prevent increased overbank flooding
Safely convey extreme floods

There are numerous structural stormwater management techniques for controlling stormwater quantity and quality. These five practices can be categorized into five broad groups:

Ponds
Wetlands
Infiltration
Filtering systems
Open channels

While many advances have been made recently in innovative stormwater management designs, their ability to maintain resource quality in the absence of other watershed protection tools is limited. In fact, stormwater management practices designed or located improperly can cause more severe secondary environmental impacts than if they were not installed at all.

Key Stormwater Choices for the Watershed Manager

Selecting the best stormwater management strategy can be a real challenge for the watershed manager. Some of the important issues and questions that watershed managers should address include the following:

What is the most effective mix of structural vs. non-structural stormwater management practices that can meet my subwatershed goals?
Which hydrologic variables do we want to manage in the subwatershed (recharge, channel protection, flood reduction, etc)?
What are the primary stormwater pollutants of concern (phosphorus, bacteria, sediment, metals, hydrocarbons, or trash and debris)?
Which stormwater management practices should be used or avoided in the subwatershed because of their environmental impacts?
What is the most economical way to provide stormwater management?
Which stormwater management practices are the least burdensome to maintain within local budgets?

Visit our Stormwater Manager's Resource Center at www.stormwatercenter.net for more detailed technical information about these and other stormwater management practices.