PARENT SESSION
TP1 - Arid Ecosystems: Unique Considerations
Chair: Gensemer, Bob1, 1 ENSR Corporation, Fort Collins, CO
Co-chair: Meyerhoff, Richard2, 2
2:10 PM to 5:30 PM - Tuesday, 19 November 2002
Room Ballroom G-I
(413) Effluent-Dependent Water Ecosystems.
Murphy, Mark*,1, Meyerhoff, Richard2, Rowan, Nicole3, Curley, Ed4, Sierra, Karen4, Gendusa, Tony5, 1 URS Corporation, 7720 N. 16th Street, Suite 100, Phoenix, AZ, USA2 CDM, 4201 N. 24th Street, Suite 205, Phoenix, AZ, USA3 CDM, 1331 17th Street, Suite 1200, Denver, CO, USA4 Pima County Wastewater Management Department, 201 N. Stone, 8th Floor, Tucson, AZ, USA5 CDM, North Last Chance Gulch, Suite 104, Helena, MT, USA
ABSTRACT- The Arid West Water Quality Research Project (WQRP) is an EPA-funded project directed by Pima County Wastewater Management (Tucson, AZ) to develop appropriate water quality standards for ephemeral and effluent-dependent waters. Effluent-dependent waters represent unique aquatic ecosystems created as a result of treated effluent discharged to an otherwise dry or intermittent streambed. These created ecosystems are fundamentally different from the dry or intermittent streams they displace; however, they are not the perennial streams they superficially resemble. The WQRP commissioned the Habitat Characterization Study (HCS) to identify physical, chemical and biological characteristics of habitats created by effluent discharge. The project evaluated ten effluent-dependent waters using historical and site reconnaissance data. Key characteristics identified include: (1) habitat quality limitations imposed by the effluent discharge itself and frequent channel modifications, especially those designed for flood control; (2) ambient water quality closely linked to effluent quality; (3) limited aquatic community expectations; and (4) creation of a riparian community providing ancillary benefits for wildlife. The HCS summarizes these findings through the establishment of an effluent-dependent ecosystem model built around accepted riverine models. Such a model is not only useful for characterizing these waters, but providing a basis for future research.
Key words: effluent-dependent, ecosystem, arid, habitat