Wahleach Project Water Use Plan Wahleach Reservoir ... - BC Hydro

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TN:TP 120 100 80 60 40 20 0 June 2004 July 2004 Aug 2004 Sept 2004 Oct 2004 Nov 2004 May 2005 June 2005 July 2005 Aug 2005 Sept 2005 May 2006 June 2006 July 2006 Aug 2006 Sept 2006 Oct 2006 P Limitation N Limitation Figure 8. Mean TN:TP (wt:wt) ratios in the epilimnion of Wahleach Reservoir, 2004- 2006. Red dashed lines indicate ratio that suggests either N or P limitation. 4.4 Phytoplankton Phytoplankton cell densities ranged from 2,320 cells·ml -1 in 2004 (one station only; no measure of variance available) to 3,770 ± 400 cells·ml -1 in 2006 (Fig. 9). Although densities increased ~50% in 2006 from 2004, likely due to higher fertilizer loading in 2006, the densities were on average 30% lower than the densities observed in oligotrophic Okanagan Lake (Stockner in Andrusak et al 2004). The low densities observed in 2004 and 2005 are similar to densities found for unfertilized Elsie Lake, a fast flushing ultra-oligotrophic coastal system (Perrin and Harris, 2006) suggesting that the fertilizer loading in 2004 and 2005, which were below the levels recommended by Perrin et al (2006), may have had limited effect on productivity. Phytoplankton biomass ranged from 0.53 mm 3 ·ml -1 in 2004 to 1.47 ± 0.09 mm 3 ·ml -1 in 2006 (Fig. 9). Despite fertilization of Wahleach, the low density and biomass clearly reflect a phytoplankton community typical of oligotrophic conditions (Wetzel 2001). Wahleach Reservoir Fertilization Project, 2004-2006. 20
Density (cells mL -1 ) 4000 3000 2000 1000 0 Density Biomass yr 2004 2005 2006 Figure 9. Annual mean density and biomass of phytoplankton community in Wahleach Reservoir, 2004-2006. A total of 53 species of phytoplankton were found in Wahleach Reservoir during the study period. Mean phytoplankton density and biomass by phytoplankton classes in Wahleach Reservoir in 2004-2005 are provided in Appendix 2. Phytoplankton species assemblages were very similar among the study years (Fig. 10). Chrysophytes and cryptophytes, both nanoflagellates, were the most abundant class followed closely by diatoms (Bacillariophytes), cyanobacteria (Cyanophytes), green algae (Chlorophytes) and dinoflagellates (Dinophytes) and (Fig. 11). The timeseries illustrates quite clearly that the Chrysophytes/Cryptophytes and the diatoms, which accounted for over 86% of the density and 69% of the biomass, were the principle groups of phytoplankton taxa in Wahleach Reservoir. Wahleach Reservoir Fertilization Project, 2004-2006. 2.0 1.5 1.0 0.5 0.0 Biovolume (mm -3 L -1 ) 21
Page 1 and 2: Wahleach Project Water Use Plan Wah
Page 3 and 4: Citation: Harris, S.L., D. Sebastia
Page 5 and 6: spawners, from 0 spawners at the st
Page 7 and 8: Table of Contents EXECUTIVE SUMMARY
Page 9 and 10: List of Figures Figure 1 Map of stu
Page 11 and 12: List of Tables Table 1. Annual fert
Page 13 and 14: 1 Introduction The Wahleach Reservo
Page 15 and 16: 3. Methods 3.1 Fertilizer Additions
Page 17 and 18: Photo 1. Old tank farm, consisting
Page 19 and 20: Nitrogen Load (mg·N·m -2 ) 140 12
Page 21 and 22: Vertical profiles of dissolved oxyg
Page 23 and 24: y gravid females and the lengths of
Page 25 and 26: hydroacoustic surveys was used in o
Page 27 and 28: 4. Results 4.1 Reservoir elevation
Page 29 and 30: 4.3 Water Chemistry The mean pH was
Page 31: Silicic acid is used by diatoms to
Page 35 and 36: Chrysoflagellates and Chryptoflagel
Page 37 and 38: 4.5 Zooplankton The zooplankton com
Page 39 and 40: Density (individuals·L -1 ) Biomas
Page 41 and 42: 4.6 Spawner Surveys The number of k
Page 43 and 44: providing some spawning opportuniti
Page 45 and 46: Kokanee spawners 10000 8000 6000 40
Page 47 and 48: Catch Per Unit Effort (# Fish·Net
Page 49 and 50: Weight (mm) Fork Length (mm) 60 55
Page 51 and 52: 4.8 Hydroacoustics Good weather pro
Page 53 and 54: strengths suggested these fish were
Page 55 and 56: Table 5 lists the range and the mea
Page 57 and 58: Wahleach Reservoir had lower total
Page 59 and 60: 6. Recommendations 1) Fertilization
Page 61 and 62: 7. References APHA. 1985. Standard
Page 63 and 64: Pick, F.R. and D.R.S. Lean. 1987. T
Page 65 and 66: Appendix 1. Phytoplankton species a

Wahleach Project Water Use Plan Wahleach Reservoir ... - BC Hydro

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