Low-Impact Development Hydrologic Analysis

Published Thursday, July 15, 1999

The purpose of this document is to provide low-impact development (LID) hydrologic analysis and computational procedures used to determine low-impact development stormwater management requirements. The hydrologic analysis presented is based on the Soil Conservation Service (SCS) TR-55 hydrologic model (SCS, 1986).

Design concepts are illustrated by the use of runoff hydrographs that represent responses to both conventional and low-impact development. Low-impact development site planning and integrated management practices (IMPs) are defined and categorized into components of low-impact development objectives. Computational procedures for determining IMP requirements are demonstrated through design examples.

The process for developing low-impact development hydrology is illustrated in Figure 1.1. This figure lists the sequential steps and the sections in the manual where the methods to calculate or determine the specific requirements are provided. 

Download the Report