Water Stewardship Information Sources
| Citation | D. Burt and Associates. 2006. Lower Jordan River Fish Index Study - Year 1 (2005). Prepared for BC Hydro. |
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| Organization | BC Hydro |
| URL | https://www.bchydro.com/content/dam/hydro/medialib/internet/documents/environment/pdf/wup_fish_index_lower_jordan_river_march_2006.pdf |
| Abstract/Description or Keywords | The Lower Jordan River Fish Index Study was initiated to assess the biological benefits a 0.25 m3 /s fish flow release from Elliott Dam anticipated to commence in 2007. The study design incorporates 2 years of pre-flow release monitoring followed by 4 years of treatment monitoring. Performance measures include fish abundance, fish condition factor, and continuity of habitat. The geographic scope includes the Jordan River from Elliott Reservoir downstream to the Jordan River Generating Station tailrace. This report presents the results of year 1 of the study (2005). Four main tasks were identified in the project terms of reference for year 1: 1) Undertake a power analysis to establish sampling intensity (number of index sites) that provides sufficient statistical power to detect differences in fish standing stock (ǻ • 100%). 2) Conduct a fish sampling program to estimate standing stock and condition factor of rainbow trout at the designated index sites. 3) Complete habitat inventories of subsections of each reach of the lower Jordan River. 4) Undertake environmental monitoring at 5 of the index sites including installation and servicing of water temperature loggers, collection of water samples for lab analysis (pH, conductivity, alkalinity, total dissolved copper, and total copper). The power analysis was performed using a 2-sample t-test model with alpha set at 0.05 and ȕ set at 0.20 (power of 80%). The terms of reference suggested using a minimum detectable difference at 100% of the mean, however, for fry it was possible to use a minimum detectable difference of 50% of the mean. Standard deviations and means were taken from the 1994 work by Griffith (1996) with the tests run using both observed and adjusted values. Power curves were generated for 0+ fry and 1+ parr and indicated that 7–10 index sites would be required to detect a 50% change in fry abundance and 19–20 sites to detect a 100% change in parr abundance. At the sample intensity achieved in 2005 (14 sites), the parr component is predicted to have a power of 66–69%. A total of 14 fish population index sites were established in 2005. Four of the sites received 3- pass removals and the other 10 1-pass removals. Maximum likelihood estimates were used to compute the fish population within the 3-pass sites. Regression analysis using data from the 3-pass sites and from Griffith (1996) was used to derive an expansion factor for estimating the populations for 1-pass sites. All salmonids captured were measured for length and weight in order to derive Fulton’s condition factor. |
| Information Type | report |
| Regional Watershed | Vancouver Island South |
| Sub-watershed if known | Jordan River |
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| Comments | |
| Project status | complete |
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