Introduction

This chapter provides guidance on selecting appropriate structural stormwater Best Management Practices (BMPs) based on the type of proposed land development activity, the applicable stormwater management requirements, the physical characteristics of the site, and other factors. The information presented in this chapter is intended to help designers and reviewers:

• Screen out unsuitable BMPs for a project site
• Select the most appropriate BMPs for a project site
• Locate stormwater BMPs appropriately on a project site
• Demonstrate that all reasonable efforts have been taken to comply with the stormwater management standards and performance criteria.

The BMP selection process and factors presented in this chapter are applicable to new development and redevelopment activities, as well as stormwater retrofits. Chapter 9 - Stormwater Retrofits contains additional information on selection considerations specifically for stormwater retrofits. Other selection factors may also be considered in addition to those described in this chapter.

Stormwater BMP Selection Process

Information and flow chart to demonstrate the recommended process for choosing the best stormwater BMP for the project / site in question.

Stormwater BMP Selection Factors

Information on stormwater management suitability along with a table which provides a comparison of BMPs category, type, retention, treatment, pretreatment, peak runoff attenuation, and if the BMP requires pretreatment.

Physical Feasibility Factors

The following site physical characteristics and how they impact the feasibility of a stormwater BMP are addressed:

• Contributing drainage area
• Site Slope
• Soil infiltration capacity (Hydrologic Soil Group)
• Depth to seasonal high groundwater and bedrock

High Risk Sites and Drinking Water Protection Areas

The following high risk site factors and how they impact the suitability of stormwater BMPs are addressed:

• Land uses with higher potential pollutant loads
• Contaminated sites
• Groundwater drinking water supply areas
• Surface drinking water supply areas

Receiving Waters

The following downstream receiving waters and how they impact the selection of stormwater BMPS are addressed:

• Coldwater streams (thermal/temperature)
• Freshwater lakes and ponds (phosphorous and sediment)
• Coastal waters and estuaries (nitrogen and bacteria)

Other Selection Factors

Other selection factors addressed are:

• Maintenance
• Affordability
• Community Acceptance and Co-Benefits