Revise the Green Infrastructure and Low-Impact Development Strategies section to read:
The goal of low impact development is to manage water as close to the source as possible using soil and vegetation-based systems. In addition to mimicking natural hydrologic cycle processes, green infrastructure and low-impact development help integrate the site with the surrounding watershed, are appropriate to the local ecosystem and climate, and deliver such other benefits as water reuse, habitat creation, and species diversity.

Prior to calculating the runoff volume from the project area, the project is encouraged to reduce the volume of runoff by protecting existing natural resources that serve to reduce the generation of runoff. Examples include healthy uncompacted soils, riparian buffers, tree canopy, etc. These areas must be protected from disturbance during the construction period in order to be effective. If protected from disturbance during construction, these natural areas can be excluded from runoff volume management.

All runoff from the chosen percentile of precipitation events must be managed such that there is no surface discharge from the site. Techniques include, but are not limited to, infiltration, storage and re-use, bioretention, open-grid pavement, and the reduction of impervious area. Infiltration may not be feasible in some cases based on the soil or geological conditions of the site. Karst geology and areas where water infiltrates at less than 1/2 inch (25 mm) per hour are two examples of situations that can be unfavorable for infiltration. The engineer, landscape architect, or rainwater professional will ultimately determine the best solution for the project’s unique conditions. Continued maintenance of all rainwater management strategies is important in order for them to remain effective over time.

Project teams should consult EPA’s National Menu of Stormwater Best Practices and consider the following questions when selecting measures for the project:
• Which GI and LID measures will best mimic natural site hydrology?
• How can multiple measures be used together (in a “treatment train” approach) to manage rainwater?
• What are the infiltration rates and capacities of the most practical measures and how might the site’s soil conditions affect their efficiency?
• What are the types and infiltration rates of existing soil conditions, and what design modifications might need to be made, if any, to the best management practices to satisfy performance goals?
• How effective are the measures at removing contaminants from the rainwater runoff?
• How will the measures be maintained?