Manastash Creek Restoration Program and Implementation of Three Nature-like Fishways

In February 2001, WEC sent a draft notice of intent to sue WDFW, Kittitas Reclamation District and West Side Irrigating Company under the Endangered Species Act relative to their operations of diversions on Manastash Creek.   Although WEC threatened litigation, it offered to sit down with the affected parties to develop a mutually agreeable plan to enhance fish passage and instream flows in Manastash Creek while ensuring the viability of local agriculture.  In response to this, the irrigators jointly developed a concept to consolidate their multiple irrigation diversions into one diversion structure to allow them to convert water lost to the “watering up” of their ditches to instream flow.  Practical limitations discovered during design required a change in concept to where three diversions were required to meet the irrigator’s needs.

The new diversions were sited at locations of old diversions and incorporate nature-like fishways  to restore passage at each of these locations.  These include two roughened channels with step pools and one roughened chute.

This presentation will present how this project was developed to where three new screened diversions now service six former diversions including an overview of the collaborative restoration program, details with regard to the nature-like fishway and lessons learned in the design, construction and operation of the facilities.