Stave River Water Use Plan - BC Hydro

Stave River Water Use Plan
Monitoring Terms of Reference June 13, 2005
indicated by the ELZ model and in situ estimates of periphyton accrual. The 4 accrual
samples will be used to estimate littoral productivity using the 14 C-calibration curve
developed in Phase 1. Every three years, a subset of transects will be subject to 14 C
inoculation to re-evaluate, and correct if necessary, the accrual – primary productivity
calibration curve.
It should be noted that data collection for Phase 1 has already been done, and
an initial data report has been prepared (Beer and Stockner 2004). However, QAQC of
the data and hypothesis testing relative to WUP objectives have not been done, nor
have the modelling exercises been started. In addition, none of the 14 C-inoculation work
has been done.
2.3 Methods
2.3.1 Field methods
Periphyton Growth Substrata
Because of the difficulty in uniformly sampling a natural substrata (e.g. sediment
surface, macrophytes, rocks, woody debris, etc.) with adequate replication, the method
of choice to collect periphyton samples will be the use of artificial substrata (e.g.
Plexiglas plates, glass slides, Styrofoam sheets, wooden sticks, etc.). In the present
study, Plexiglas plates will be used. These plates will be attached to concrete blocks
(25-30 kg) placed or dug into the sediment along a transect line that extends from the
‘splash’ zone to 1m below the mean compensation depth (1% light level) of the reservoir
at low pool (see Figure 2-1). The blocks will be placed at depth intervals between 1.5
and 2 m.
The Plexiglas plate will be elevated above the anchor block to permit movement
of water on both sides. The surface of each plate will be scored with fine sandpaper to
create a surface suitable for algae attachment. Plates will also be scored with a
diamond pen into ‘quadrants’ to permit accurate quantitative sampling (see inset, Figure
2-1). A 10 x 10 cm quadrant (100 cm 2 ) usually supplies sufficient periphyton to easily
detect temporal changes in biomass and species composition in most oligotrophic lakes
or reservoirs (Shortreed et al. 1984). To monitor accrual rates, quadrant sizes need not
be as large. For the present study, the accrual quadrants were only 2.5 x 10 cm (25
cm 2 ) in size. Thus, each plate was partitioned into three 100 cm 2 quadrants, each to
sample for species composition, Chlorophyll a and ash free dry weight biomass
estimates, and eight 25 cm 2 quadrants to carry out accrual sampling (see below).
During Phase 1 of the monitor, all quadrants will be sampled (scraped) and
placed into separate sample vials for appropriate analysis. During phase 2 of the
monitor, sampling will be reduced to only one 100 m 2 quadrant, which will be used to
estimate accrual through ash free dry weight analysis. When necessary, a second
quadrant may be scraped for 14 C production estimation (see below).
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