The Use of Normalized Duration to Evaluate Low Flow in Mississippi Streams

Author(s): Johnson, D.

Currently the Mississippi Department of Environmental Quality uses the lowest observed flow in seven consecutive days occurring in ten year period (7Q10) to establish minimum flows for streams. The 7Q10 is a minimum flow established for wastewater discharges, but it does not address the needs of aquatic organisms. The period of record flows from 128 streams in Mississippi were analyzed for annual duration. An index was developed based on the mean annual duration distribution. The index was compared to several methods that are commonly used to establish minimum environmental flows.

Go back


Past Conference Archive