Monitoring Effectiveness of EWRs

Once implemented, it is necessary to monitor the effectiveness of EWRs for maintaining water dependent ecological values of creeks and rivers.

Such monitoring is typically required as part of allocation licence conditions. WRM undertake monitoring of rivers downstream of various water resource developments (e.g. Wungong Dam, Serpentine Dam, North and South Dandalup Dams) for the WA Water Corporation, assessing changes, if any, in fish and crayfish populations. This is achieved using a standard protocol developed by the State Department of Water for ecological condition assessment.

The protocol involves semi-quantitative non-lethal sampling for fish and crayfish (fyke nets & box traps), in situ water quality measurement, visual appraisal of habitat/shoreline condition and opportunistic sightings of tortoise, water rat or other vertebrate aquatic fauna. For example, in the North and South Dandalup River, WRM assessed fish and crayfish populations using baited box traps and fyke nets, supplemented with electrofishing. Dual fyke nets were set in permanent pools and oriented to provide data on directional movement of fish/crayfish into the pool from either upstream or downstream. Nets and traps were deployed for 24 hours. Catch data from electrofishing was standardised using shocker ‘on time’ in seconds, and thereby provided a relative measure of CPUE.

Available historic data collected by the University of Western Australia during the mid to late 1980s were used as the reference condition against which to compare current data.