October B.c. Siocan South - a100.gov.bc.caa100.gov.bc.ca/appsdata/acat/documents/r39334/Cayoosh...village of Lillooet, B.c. approximately 180 kilometers northeast of Vancouver, B.C

TISDALE ENVIRONMENTAL CbNSULTING Inc.

2228 PAUL LAKE RD KAMLOOPS B.C V2H I N9 PHONE 250-573-4572 FAX 250-573-4552 Email [email protected]

CAYOOSH CREEK

GRAVEL RECRUITMENT

AND

ENVIRONMENTAL MONITORING

2003

Prepared by:

A.E. (Gene) Tisdale, AScT Tisdale Environmental Consulting Inc.

Prepared for:

Aquila Networks Canada Site 2, Compo 1, RRI

3100 South Slocan Station Road South Siocan B.c.

October 2003

mailto:[email protected]

EXECUTIVE SUMMARY

Tisdale Environmental Consulting Inc. was contacted by Ms. Sue Dyer of Aquila

Networks Canada to provide environmental support at the Walden Power plant during

implementation of gravel management techniques and biophysical monitoring on

Cayoosh Creek.

The Walden Power forebay was operated throughout the freshet period with the radial

gate in an undershot position. This allowed gravel moving downstream with the current

to continue through the forebay and into the lower reaches of Cayoosh Creek. The

forebay was drawn down on two occasions near the end of the descending hydro graph,

July 04 and July 10, 2003, to encourage mobilization of settled gravel within the forebay.

Re-mobilized gravel settled within the lower reaches of Cayoosh Creek where it could

later be utilized as spawning gravel by both non-anadromous (resident) and anadromous

species of fish. Following forebay gravel mobilization, three size classes of gravel (2.5,

5.0 and 7.5 cm diameter respectively) were each painted with a unique color per size

class and placed within Cayoosh Creek. Locations chosen (sites 1-3) were downstream

of the forebay and known to be previously utilized as spawning habitat by anadromous

fish. These sites were monitored to determine hydrological movement patterns of the

various sizes of gravel. All painted gravel remained where placed through ramping

events, but was displaced during pink salmon spawning activity in September 2003.

Cayoosh Creek Gravel Recruitment and Environmental Monitoring 2003 Tisdale Environmental Consulting Inc. ii.

TABLE OF CONTENTS

Page

TITLE PAGE ....................................................................................................................... i EXECUTWE SUMMARY ................................................................................................ ii TABLE OF CONTENTS ................................................................................................... iii LIST OF FIGURES, TABLES AND PLATES ................................................................. iv

1.0 INTRODUCTION ......................................................................................................1 1.1 Study Area ............................................................................................................. 1 1.2 Background ............................................................................................................ 1 1.3 Walden Power Plant Operations ............................................................................2 1.4 Ramping Guidelines .............................................................................................. 4 1.5 Water Quality ......................................................................................................... 5

2.0 MATERIALS AND METHODS ...............................................................................9 2.1 Water Quality Monitoring ..................................................... ................................9 2.2 Stage Change Monitoring ......................................................................................9 2.3 Fish Salvage ........................................................................................................... 9

3.0 RESULTS AND DISCUSSION ............................................................................... 11 3.1 July 04, 2003 ........................................................................................................ 11 3.2 July 10, 2003 ........................................................................................................ 12 3.3 Gravel Monitoring ............................................................................................... 13 3.4 Fish Salvage .... ................................................. .......................... ......................... 15

4.0 CONCLUSIONS AND RECOMMENDATIONS .................................................16

5.0 ACKNOWLEDGEMENTS .....................................................................................17

6.0 LITERATURE CITED ............................................................................................18

Cayoosh Creek Gravel Recruitment and Environmental Monitoring 2003 Tisdale Environmental Consulting Inc. iii.

LIST OF FIGURES

Page

Figure 1. Bridge/Seton River Watershed ........................ ..................................................7

Figure 2. Cayoosh Creek and relative locations of water quality and gravel study sites.................................................................................. ..................................8

LIST OF TABLES

Table 1. B.c. HydrolDFO Ramping Rate Guidelines ...................................................... .4

Table 2. Water Quality and Event Summary for July 04,2003 ....................................... 12

Table 3. Water Quality and Event Summary for July 10,2003 ....................................... 13

LIST OF PLATES

Plate 1. Three sizes of gravel, painted red, yellow and white to identify each size, was placed in three locations along Cayoosh Creek. This site (#GR-l) was located approx. 100m downstream of the Walden Power plant.. 14

Plate 2. This site (site #GR-2) was located immediately downstream of the CCSRC confluence ............................................................................................ 14

Cayoosh Creek Gravel Recruitment and Environmental Monitoring 2003 Tisdale Environmental Consulting Inc. iv.

1.0 INTRODUCTION

1.1 Study Area

Aquila Networks Canada (Aquila) -Walden Power is located on Cayoosh Creek near the

village of Lillooet, B.c. approximately 180 kilometers northeast of Vancouver, B.C

(Figure 1). This 16 MW generating facility is located on the left (west) bank ofCayoosh

Creek approximately 2 km upstream of the Cayoosh Creek and Seton River confluence.

This is a run of the river type generating facility in which water held in a forebay area by

a radial gate is diverted into a penstock intake. The penstock splits near the powerhouse

and discharges into one of five Francis-type generating turbines rated at 3.2 MW each.

Water is expelled from the generators into a tailrace pond and then either diverted back

into Cayoosh Creek via four diversion culverts or into the tailrace channel and into Seton

Lake reservoir via a tunnel. An intake structure in the tailrace channel supplies water to

the Cayoosh Creek Compensatory Spawning and Rearing Channel (CCSRC) (Figure 2).

The Walden Power plant is operated under contract by B.C. Enertech Ltd. (BCE) for

Aquila.

1.2 Background

Aquila Networks Canada has had an ongoing problem with gravel settling in the forebay

of Walden Power. Gravel (2.5 cm diameter) begins to mobilize in Cayoosh Creek at

approximately 1500 cfs. Due to the typical run-of-the-river configuration of the Walden

Power plant, the forebay area required to store water and create head pressure for power

generation also acts as a settling area for migrating gravel. Accumulations of gravel in

the forebay are drawn into the penstock intake and subsequently through the turbines.

This creates excessive mechanical wear at the Walden Power plant, deposits large

amounts of gravel into the tailrace area and removes valuable fisheries-related gravel

potential from the lower reaches of Cayoosh Creek.

To help alleviate gravel build-up during freshet periods, the radial gate is typically

operated in an undershot position in an attempt to entrain gravel migrating along the

Cayoosh Creek Gravel Recruitment and Environmental Monitoring 2003 Tisdale Environmental Consulting Inc. 1.

thalweg into the lower reaches of Cayoosh Creek. Various berm configurations have

been designed and installed in the forebay by hydrological experts. Unfortunately, all

attempts to date have been unsuccessful in passing all gravel (and debris) migrating

through the forebay while drawing only water through the turbines.

1.3 Walden Power Plant Operations

The forebay operating elevation can be controlled manually, by the gate operator, or

electronically, by a programmable logic computer (PLC). The PLC will control the

elevation of the forebay by either manipulating the opening of the radial gate or

increasing/decreasing generation at the power plant. PLC ramping (flow manipUlation) is

controlled by feedback from pressure sensitive transducer readings (electronic staff

gauge). This transducer is located in Cayoosh Creek mainstem adjacent to the Walden

Power plant. When water is being diverted through the diversion culverts into Cayoosh

Creek, a backwatering effect at Walden Power's upper transducer site occurs resulting in

conservative ramping rates. When the diversion culverts are closed a more accurate

ramping rate occurs. When ramping rates calculated at this transducer exceed

predetermined settings, the PLC will suspend gate movements until ramping criteria is

within acceptable limits.

A fluctuation in stream elevation is typically noted in Cayoosh Creek throughout the day

during spring and early summer. This increase and decrease in discharge is directly

correlated to weather conditions, air temperature and snowpack. The four diversion

culverts discharging from the tailrace area into Cayoosh Creek mainstem are typically

open during freshet conditions, but were closed during the 2003 freshet period. Much of

the discharge (approximately 500-600 cfs) being utilized by the generating plant IS

redirected back into Cayoosh Creek through these four diversion culverts.

The radial gate is typically closed throughout periods of low discharge and typically

results in free-crest spilling over the top of the gate when one or more generators trip off

line. During ramping procedures, at periods of low discharge, balancing the forebay and


maximum generation through the plant (completion of ramping) is easily determined

when free-crest spilling is no longer occurring. During periods of high discharge

(freshet), the gate is typically set to release water undershot (under the gate) leaving the

top edge of the gate higher than what would be observed during periods of low discharge.

Free-crest spilling will not typically occur unless excessively high forebay levels are

noted i.e. a unit tripping off-line will not typically cause a free-crest spill condition.

Ramping during freshet conditions is complete when either the final generating unit being

brought on-line achieves 100% generation or the radial gate closes.

Due to the relative location of the five generating units (numbered #2 through #6) to the

bifurcation of the penstock, prior to entering the generating plant, a majority ofthe gravel

and large woody material coming from the forebay is shunted to unit #6 with less to unit

5 etc. and the least entering unit #2. Ramping is typically undertaken with unit #4 as this

unit has the smoothest operation of the five generating units. A generating unit is

typically brought to speed-no-Ioad (SNL) prior to being brought on-line. SNL indicates

the turbine is spinning but is not generating electricity. Initiation of a generating unit to

SNL typically requires an instantaneous extraction of approximately 60 cfs directly from

Cayoosh Creek mainstem to initiate the turbine spinning. A reduction of 60 cfs, or 20%

generation (each unit requires approximately 300 cfs to operate at 100% generation),

from an operational unit while simultaneously initiating SNL with a second unit dampens

the negative elevational effect (stage differential) on Cayoosh Creek. The creek elevation

is read at the Water Survey Canada Station 08ME002 located on Cayoosh Creek (WSC

CAY) (Figure 2). During periods of high discharge (> 1500 cfs) there is limited potential

for stranding/isolating fish, as determined by reconnaissance, and generating units are

individually brought to SNL instantaneously without simultaneously reducing the load on

an adjacent operational unit by 20%. Approximately 45 minutes is required to fully

realize stage differential at WSC-CA Y as a result of plant discharge manipulations at the

forebay. A natural variation, or 'bounce', of approximately 1.5 cm is noted in the stage

readings at the WSC-CA Y at high stream discharge. To achieve an accurate creek

elevation reading, four consecutive readings are collected remotely from the WSC-CA Y

station via a dial-up modem and an average is calculated.


1.4 Ramping Guidelines

B.c. Hydro and Power Authority (BC Hydro) and the DFO have undertaken research in

order to determine ramping rates that reduce the incidence of stranding in salmonids

(Bradford et aI, 1995). Ramping rates are temporal, temperature and species specific.

The rates of flow fluctuations in river levels are used as a measure oframping rates. The

present ramping rate guidelines can be found in Table 1.

Table 1. BC HydrolDFO Ramping Rate Guidelines.

TIME OF YEAR LIFE DAY RAMP NIGHT RAMP COMMENT HISTORY RATE RATE

STAGE

April 01-July 31 Fry

Emergence 0-2.5 cmlhr 2.5 -5.0 cmlhr a) see below

Rearing Aug. 01 -Oct. 31 until temp. 0-2.5 cmlhr 5.0 -10.0 cmlhr b) see below

< 5.0 C.

Nov. 01 -April 01 Winter Rearing

Ocmlhr ~ 5.0 cmlhr -

c) see below

a) The fry emergence period includes rainbow trout. Field studies suggest that rainbow trout fry can be stranded both during the day and night.

b) Ramping rates could be slower during the rearing period to accommodate small rainbow trout fry.

c) During winter, ramping during the day must be avoided. Night ramping rates should be slow (i.e. <5.0 cm/hr). The beginning of this interval is determined by water temperatures <5.0 Celsius. (B.Hebden, BC Hydro, 1998).

The area surveyed during this fish salvage and flow manipulation included Cayoosh

Creek from Pick's Falls downstream to the confluence of the Seton River (Figure 2) and

the Seton River from the confluence with Cayoosh Creek to the confluence of the Fraser

River.


1.5 Water Quality

Turbidity is a measurement of the ability of light to penetrate into a liquid (in this case,

water); it is measured in Nepholemetric Turbidity Units (NTU's). Affecting properties

range from tannic water, to glacial till, to silt, etc. Ministry of Environment, Lands and

Parks (MoELP) outlines a guideline for water quality criteria concerning aquatic life for

particulate matter. For periods during clear flow: "Induced suspended sediment

concentrations should not exceed background levels by more than 25 mg/I (8 NTU's)

during any 24-hour period. For sediment inputs that last between 24 hours and 30 days,

the average suspended sediment concentration should not exceed background by more

that 5 mg/l (2 NTU's)." During periods of turbid flow: "Induced suspended sediment

concentrations should not exceed background levels by more than 25 mg/I (8 NTU's) at

any time when background levels are between 25 and 250 mg/l (8-80 NTU's). When

background exceeds 250 mg/I (80 NTU's), suspended sediments should not be increased

by more than 10% ofthe measured background level at anyone time." (Singleton, 1997).

Total suspended solids (TSS) is a physical measurement of actual material suspended

within a solution and described in mg/I. (personal communications L. Campbell, ASL

Laboratories, 1998). According to Newcombe and MacDonald (1991), impacts to aquatic

life can be more accurately assessed with the measurement of TSS, rather than turbidity.

They suggest modeling of concentration of sediment pollution, combined with duration

of exposure, has predictable physical and behavioral effects on aquatic biota that can be

measured and applied to a scale rating of 1-14 (1 is increased coughing in fish, 14 is 80 to

100% mortality). They also conclude that more data is required before this model can be

used as a management tool.

TSS cannot be measured in the field. Accurate turbidity measurements can, however, be

made in the field using a portable turbidity meter to gain real-time measurements for on

site monitoring of sediment management techniques. Turbidity measurements can be

used as a relative index of TSS (personal communication D. Holmes, 1999 Env. Section

Head, Pollution Prevention Branch, MoELP). Each stream consists of a unique set of


biophysical characteristics including size and composition of sediment. A correlation can

be shown between turbidity and TSS for each particular stream and used for practical

application in the field.


125km

~~~

/

Kilom

eters

o 5

10 15

20

Figure 1. B

ridge/Seton R

iver watershed.

7

~»

WQ-l

D Forebay Area Walden Power

Penstock

China Gate Radial Gate Diversion Twmellnlet

.-Pick's Falls

Upper Transducer Location and WQ-2

Gravel Study -Sites GR-I-GR-3 q Water Quality -Sites WQ-l-WQ-2 ~ Seton Canal Aqueduct o~

Q ~~

KilometaB Water Survey Canada Station

Highway Bridge 08MEOOI

o 0.25 0.5 0.75 1.0

Seton River Confluence ~(

Figure 1. Cayoosh Creek showing relative location of water quality and gravel study sites.

8

2.0 MATERIALS AND METHODS

2.1 Water Quality Monitoring

An HF Scientific Model DRT -15CE turbidity meter was utilized to collect turbidity

measurements (Nepholemetric Turbidity Units -NTU's). The meter was calibrated using

a 0.02 NTU calibration cuvette prior to collection of field data. Three readings were

recorded from each cuvette sample over a period of thirty seconds. A mean, standard

deviation and variance were calculated from the three readings. Air and water

temperatures were recorded at each site using a red spirit-filled, glass-stemmed pocket

thermometer.

2.2 Stage Monitoring

Creek elevational change (stage change) was monitored via dial-up modem at WSC

CAY. A pressure sensitive transducer, installed into Cayoosh Creek adjacent to the

Walden Power plant, is also used for monitoring stage differential as well as for PLC

ramping. (Figure 2).

2.3 Fish Sa]vage

Cayoosh Creek was monitored by a four person fish-salvage crew equipped with Smith

Root Model 12B battery powered backpack electro fishing equipment and outfitted

accordingly as per Workers' Compensation Board standards.

Crews are typically deployed along each shoreline during all discharge manipulations.

All portions of Cayoosh Creek were examined from the confluence of Cayoosh Creek

and Seton River upstream to Pick's Falls located immediately upstream of the Walden

Power generating facility. Some areas of the Seton River downstream of the Cayoosh

Creek confluence require salvaging and are monitored as well. Any fish captured were

identified to species, as described by Scott and Crossman, 1973, measured for fork

length, as described by MoELP, 1995, and live fish were released unharmed into the main

channel. Mortalities, if recovered, were to be retained and preserved in Davidson's

Cayoosh Creek Gravel Recruitment and Envirorunental Monitoring 2003 Tisdale Environmental Consulting Inc. 9.

Solution as per DFO request. Physical condition of fish was noted (live or mortality), as

was location (stranded, isolated or incidental capture). Stranded fish are those recovered

that are no longer in water. Isolated fish are those recovered from pools which cannot

return back to the mainstem stream. Incidental fish are those captured while removing

fish from areas that may dewater in the future.

2.4 Gravel Monitoring

Gravel was collected from various bar areas within the channel of Cayoosh Creek to

ensure similar profile to that of naturally occurring gravel within Cayoosh Creek. Three

size classes were collected, 2.5, 5.0 and 7.5 em diameter, and painted red, yellow and

white respectively. Once the paint had thoroughly dried, the three gravel sizes were

mixed in equal proportions within a 25 liter bucket and placed into Cayoosh Creek at

locations pre-determined to have been used as spawning sites by anadromous fish. These

locations were located approximately 100m downstream of the diversion culverts

confluence (Site #GR-l), immediately downstream of the CCSRC confluence (Site #GR

2), and immediately downstream of the Seton Aqueduct crossing (Site #GR-3). All

locations were monitored on an opportunistic basis.


3.0 RESULTS AND DISCUSSION

3.1 July 04, 2003

Water quality samples were collected from two locations within Cayoosh Creek prior to

initiation of forebay reduction; approximately 100m upstream of the forebay (Site #WQ

1) and adjacent to the Walden Power plant (Site #WQ-2) (Figure 2). Resulting

background turbidity readings were 4.92 NTU's at 0545h and 5.21 NTU's at 1600h

respectively with a creek elevation of 1.499m (424 cfs) at WSC-CA Y (Table 2). Prior to

initiation of flow manipulation, generating units # 2 and #4 were operational at 100%,

unit #3 was at 82%, unit #6 was at 55%, and the forebay was stable at 289.08m. At

1615h, generating unit #3 was decreased from 82% generation to 52%. At 1715h, unit #3

was decreased from 52% to 19% (off-line) to SNL. This resulted in an increase in

Cayoosh Creek elevation at WSC-CA Y to 1.690m (657 cfs); an increase of 19.1 cm (233

cfs). At 1745h, unit #6 was decreased from 55% to off-line and then shut down. At

1800h, unit #2 was decreased from 100% to 57% generation and then shut down at

1850h. The forebay elevation was reduced to the lowest point of transducer range

(288.683m) at 2153h while continuing to maintain electrical control (PLC) of the

forebay. Gravel began to move in the forebay as a result of decreased elevation prior to

achieving the lowest elevation. Although discharge increased in Cayoosh Creek

downstream of the forebay as a result of decreasing generation at the power plant,

turbidity readings remained fairly constant at site #WQ-2 (Table 2). Turbidity readings

increased to a maximum of 15.3 NTU's (10.1 NTU's over background readings) at site

#WQ-2 by 2135h with a WSC-CAY creek elevation of 1.888m (1002 cfs). The turbidity

had decreased to 8.21 NTU's by 2200h. Unit #4 remained operational generating at

100%. Forebay operating parameters required electronic adjustment to lower the

elevation even further and complete the gravel mobilization.


Table 2. Water Quality and Event Summary for July 04,2003

3.2 July 10,2003

Water quality samples were collected at exact locations to July 04, 2003 at sites #WQ-l

and #WQ-2. Resulting background turbidity readings were 4.62 NTU's at 0720h and

4.61 NTU's at 0700h respectively with a WSC-CA Y creek elevation of 1.883m (991 cfs)

at 0615h. Prior to flow manipulation, generating unit #4 was operational at 100% and the

forebay was stable at 289.10m (Table 3). Unit #4 was decreased from 100% to 59% at

0715h to initiate forebay reduction. Cayoosh Creek elevation at WSC-CAY read 1.950m

(1138 cfs) at 0814h; an increase of 147 cfs (6.7 cm). Unit #4 was shut down at 0855h

when gravel began to be drawn in to the penstock intake due to low forebay elevation.

Turbidity readings at site #WQ-2 increased to 22.7 NTU's by 0915h, as the forebay

gravel began to mobilize, and continued to increase to 38.6 NTU's by 0930h. One of the

four diversion gates between the Walden Power tailrace and Cayoosh Creek mainstem

was opened at 1000h to ensure an adequate supply of water to CCSRC. Cayoosh Creek

elevation, at WSC-CAY, increased to 1.934m (1101 cfs) by 1024h where it remained

relatively stable throughout the day. Turbidity readings slowly increased over the day to

a maximum of 45 .2 NTU's at 1730h. The forebay gravel was visibly decreased by


1600h and the radial gate was lowered slightly at 1610h, 1840h, 1905h and 1915h. The

forebay elevation began to increase at 1905h and gravel mobilization was stopped.

Turbidity readings decreased to 29.7 NTU's by 1930h at site #WQ-2. With the forebay

stabilized and gravel mobilization completed, Units #2 and #4 were brought back on-line

from July 11 -21, 2003 with appropriate fish salvage techniques and monitoring.

Results from this ramping event will be provided in a separate document.

Table 3. Water Quality and Event Summary for July 10, 2003

3.3 Gravel Monitoring

Three size classes of gravel (2.5, 5.0 and 7.5 cm diameter respectively), with each size

class painted with a unique color, was placed within Cayoosh Creek at locations known

to be used as spawning habitat. Painted gravel was placed on July 24, 2003 at

approximately 141 cfs.


Plate I. Three sizes of gravel, painted red, yellow and white to identify each size, was placed in three locations along Cayoosh Creek. This site (#GR-l) was located approx. 100m downstream of the Walden Power plant.

Plate #2. This site (site #GR-2) was located immediately downstream of the CCSRC confluence.

Cayoosh Creek Gravel Recruitment and Environmental Monitoring 20m Tisdale Ellvironmental COllsulting fllc. 14.

Walden Power tripped off-line on July 25, 2003 resulting in an increase in discharge at

WSC-CA Y to 367 cfs. All three sites were monitored following flow reductions to

determine hydrological movement of the various sizes of gravel. All painted gravel

remained where placed through this ramping event with no visible displacement of any

gravel size. Painted gravel was monitored opportunistically throughout August and early

September; all painted gravel remained where placed. When monitored on September

14, 2003, much of the painted gravel had been displaced by pink salmon spawning

activity. Very few of the painted gravel, of any size, could be located.

3.4 Fish Salvage

No fish were located that had been isolated or stranded as a result of this gravel

recruitment procedure.


4.0 CONCLUSIONS AND RECOMMENDATIONS

The technique used for forebay management during the 2003 season was successful in re

mobilizing much of the gravel that had settled within the forebay area. Management

techniques were also successful in permitting the re-mobilized gravel to settle and

maintain placement in the lower reaches of Cayoosh Creek where it was later utilized by

spawning fish. It is, therefore, recommended that future forebay gravel mobilization

begin at approximately 1500 cfs total discharge. Monitoring of water quality data during

the gravel mobilization should be continued in an attempt to further assess potential

impacts to the aquatic environment. Data had been collected prior to oncoming freshet

conditions, in May of 2003, in a joint effort by DFO and Aquila Networks Canada for use

in a habitat simulation model. Data collected included detailed topographical

measurements of the braided area located between CCSRC and the diversion culverts.

Additional data could be collected in the spring of 2004 using the same transects may

provide insight into quantifying depths of newly deposited gravel within this area.


5.0 ACKNOWLEDGEMENTS

I would like to thank Dean Grant and John Barten (plant operators -BCE), Kevin

Goforth, Kirk Goforth, Tyson Goforth, Terry Adolph and Bob Vinnie (Tisdale

Environmental Consulting Inc.) for their efforts in data collection.


6.0 LITERATURE CITED

Higgins P.S. and Bradford M.l 1996. Evaluation of a large-scale fish salvage to reduce the impacts of controlled flow reduction in a regulated river. North American Journal of Fisheries Management 16:666-673, 1996.

Ministry of Environment, Lands and Parks. 1995. Lake and Stream Inventory Standards and Procedures. Fisheries Branch, Inventory Unit. Victoria, B.C. 227 pp

Newcombe, c.P. and MacDonald, D.D. 1991. Effects of Suspended Sediments on Aquatic Ecosystems. North American Journal of Fisheries Management 11 :72-82.

Scott, W.B. and Crossman, EJ. 1973. Freshwater Fishes of Canada. Bulletin 184. Fisheries Research Board of Canada, Ottawa 1973.

Singleton, H.J. 1997. Ambient Water Quality Criteria for Turbidity, Suspended and Benthic Sediments. British Columbia Ministry of Environment, Environment and Resource Division, Water Management Branch.

Cayoosh Creek Gravel Recruitment and Envirorunental Monitoring 2003 Tisdale Environmental Consulting Inc. 18.

Documents

October B.c. Siocan South - a100.gov.bc.caa100.gov.bc.ca/appsdata/acat/documents/r39334/Cayoosh...village of Lillooet, B.c. approximately 180 kilometers northeast of Vancouver, B.C