Minimum Instream Flow Methodology
Minimum streamflow information is commonly used to determine the water available for extraction and to analyze instream environmental parameters. Minimum streamflow estimates are frequently desired at ungaged locations, either on a stream having gages at other locations, or a stream without any gages. The firm developed regional regression equations to estimate minimum streamflow using two parameters: watershed area and mean annual rainfall. These equations are based on a revised rainfall map which incorporates the available rainfall data from 127 rain gage stations and also considers geographic parameters.