Illinois Streamflow Assessment Model

The Illinois Streamflow Assessment Model (ILSAM) is an online Geographic Information Systems (GIS) application that provides streamflow magnitude and frequency information — focusing on average flow to low flow — for water resources management and water supply planning in Illinois.

ISWS began developing ILSAM in 1985 and has since created models for the Sangamon, Fox, Kaskaskia, Kankakee, Little Wabash, Rock, and Middle Illinois watersheds. ILSAM is applicable for drainage areas of 10 square miles or greater.

Streamflow Parameters

ILSAM provides information for 105 selected streamflow parameters, including:

• flow-duration (flow versus exceedance percentage of duration) relationships,
• low flows for various durations and expected return intervals, and
• drought flows for a range of durations and return periods.

All parameter values are in cubic feet per second (cfs). Estimates of all streamflow parameters are presented for both present and virgin (natural or unaffected) flow conditions.

Questions?

For questions or comments, please email Wei Dang.