• . i' .' .', . -i' Cofumbia Basin Fish. & ~il.dJjfe CO:n1pen.sa"tio:n. Progra:n1

103 - 333 Victoria Street, Nelson, VIL 4K3 Phone: (250) 352-6874 Fax: (250) 352-6178

Arrow Lakes (Resei oir) Historical Repolt and Bac grounder,

Impact of dams a I d BCE Fisheries Managemer t Direction

by Bob Lindsay, BCE Fisn Biologist

h9\ti l ~s. '-\

BChydro m BC~Environment , (

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BACKGROUN I

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The Arrow Lakes were originally two large oligotro hic lakes lying between the Selkirk and Monashee Mountain ranges in southeastern ritish Columbia (Fig. 1). They were made into a reservoir when the near ,Castlegar was constructed in 1969. The lakes are dominated by the inflowing C lumbia River near Revelstoke and '- I., the outflowing near Castlegar. At full pool the Arrow Lakes have a surface area of approximately 51,800 ha (Upper rrow 28,000 ha and Lower Arrow 23,800 ha). The Upper Arrow has six major tribut ries and 25 minor tributaries; the Lower Arrow has four major tributaries and 26 min r tributaries (Figures 2 and 3). The communities of Revelstoke, and Castlegar re located on or near the lakes.

Traditionally, the Arrow Lakes supported a variety I f sport fish including rainbow trout (Oncorhynchus mykiss), bull trout (Salvelinus Jon fluentus) , kokanee (0. nerka), mountain whitefish (Prosopium williamsonl) , burb t (Lota Iota), and white sturgeon (Acipenser transmontanus). Prior to dam constru ,tion activity on the Columbia River (J!"/~" S/I:.VllfI IN,,) in the United States, the Arrow Lakes system al 0 supported anadrornous runs of chinook salmon (O. tshawytscha) and steelhead tro t. Anadromous fish were known to spawn in the narrows between the two lakes and in the Upper Columbia River near Invermere using the Arrow Lakes primarily for rearing.

MANAGEMENT DIRE TION

The goal of the provincial Fisheries Program is to d..Q.O§elYathe_natural diversity of fi _ and fish habitat, and to sustainably manage f eshwater sport fishing in British ------~.--~ ------.~~--- -- . ---._--_ .. - --- - .-,. ---- Columbia. To achieve this goal, the Fisheries P ogram has adopted four strategic priorities:

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1. conserve wild fish populations and their habi ts; 2. manage for the sustainable use of fish;

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3. build support for resource stewardship; and 4. support cooperative arrangements with First ations.

In order to achieve these priorities the Fisheries Program has developed numerous strategies and activities. The reader is encourag d to review the Fisheries Program Strategic Plan entitled "Conserving Our Fisheries esources; 1996 - 2000" for a more { , , detailed description of strategic priorities and activit es.

The Kootenay Region is one of numerous admini trative zones within the Ministry of Environment, Lands and Parks. These regions ar the 'delivery arms' for the various programs of the Ministry. The Fisheries Program i located in VictoriaNancouver and deals primarily with policy, research and devel pment, fish culture, and support services for the regional operations.

The goals of the Kootenay Region Fisheries Se tion mirror those of the provincial Fisheries Program. Certain strategies and activiti are not necessarily applicable to the Kootenay, for example, we do not have anadro ous fish, but for the most part this region is driven by the aforementioned strategic pri

FISH AND HABITAT L

The flooding of the two lakes eliminated 30% of the spawning and rearing habitat in the Arrow Lakes Basin (Lindsay and Seaton 1978). Th lakes were further impacted by the construction of the Mica Dam on the upper Columbi River in 1973. No estimate of fish losses was made before this dam was built howe er, it was later 'discovered' that at . least some of the trophy rainbow from the Arrow L kes spawned upstream of the Mica Dam in specific Canoe River tributaries. The last, a d probably most significant, impact

on Arrow Lakes fish stocks was the construction 0 the in 1984. This dam flooded 150 km of the mainstem Columbia Ri er and 200 km of tributary streams

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which were used by Arrow Lakes kokanee, bull trout, and, to a lesser extent, rainbow trout.

The Arrow Lakes traditionally supported a tro hy rainbow trout fishery for the .ps h -fU'-i'-9

dam construction (1,000 spawners and 2,000 fish f om the sport fishery). The spawner I. ' ' estimate is based on the return of 500 fish to the b se of the Revelstoke Dam (Martin 1976) and an additional 500, which according tf area residents, spawned in the narrows between the two lakes. The sport harvest estimate is loosely based on Kootenay Lake data where the annual harvest is riCe the escapement. These fish were large (up to 14 kg in size) but quite distinct from Gerrard rainbow trout (yellow­ orange colour on their bellies, and pectoral, pelvic ·~nd anal fins). The flooding of the lakes almost completely eradicated this stock, anf from the mid-1970's through the early 1980's, very few of these fish were caught. From 1979 through 1981, attempts were made by the Fisheries Section to preserve aId enhance this stock by collecting spawning adults blocked at the Revelstoke Dam. S me yearling releases. resulted from these collections, however, this program was too I bour-intensive and to.o few adults were collected to justify its continuation. Attempts Jfre made again from 1992 through 1996 to collect spawning adults to preserve thi unique stock but few fish were captured. , i In addition to the trophy rainbow trout, there is a stork of smaller-sized rainbow that are popular with anglers. An estimated 1,250 yearly sPjwners were lost as a result of the 30°fc:, habitat loss caused by flooding of the laker (Lindsay 1978) as well as 500 spawners which utilised streams tributary to the ColJmbia River north of the Revelstoke Dam (Martin 1976).

Bull trout were traditionally one of the main target :species in the Arrow Lakes. The I impacts from dam construction on this species have reen dramatic primarily because of flooding and blocked access to spawning and r,aring habitat. As a result of the Revelstoke Dam, it was estimated that 4,000 ad It spawners (13 spawners/km of

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stream habitat) were lost (Martin 1976). The number of km of habitat lost in comparison with remaining habitat in the"'Arrow sy tern represented a loss of 66% of the total adult spawning population in the lake ( indsay 1977); the total bull trout spawning population was therefore estimated at a out 6,000. Combining an average fIJ~ i'/"" yearly sport harvest from 1976 through 1983 of ,000. fish, then the total pre-dam t\.o.~~ population was about 8,000 adults. The significa effect of dams on this stock was l~~ ~ I.. '., evident through yearly creel census data coli ted on the Upper Arrow which demonstrated a dramatic decline in catch from th early 1980's through 1986. This decline was also apparent from time series catch d ta collected from Nakusp as well as subsequent brood collection activities downstream f the Revelstoke Dam.

Arrow Lakes kokanee have been severely impa ted by hydro development. The Keenleyside Dam flooded 300/0 of their spawning abitat (Lindsay and Seaton 1978) while the Revelstoke Dam blocked upstream pas age to 500,000 spawners (Martin .1976). The pre-impoundment annual escapement i the Upper and Lower Arrow Lakes was estimated at 1 million and 800,000, respecti Iy (Lindsay 1979). These figures were calculated using a combination of esti ated losses, post-ir:npoundment escapements, and a 30% loss in tributary spawni g habitat as a result of the initial

flooding of the lakes. More recent kokanee abun ance estimates from hydroacoustic ~ surveys suggest that the pre-iimpoundment spawni g population may have been in the order of 1.2 to 1.4 million kokanee rather than 1.8 iIIion. However, given the changes that have occurred in the lakes as a result of dam d velopment, i.e., impoundment, loss of tributary habitat, drawdown, entrainment, etc., ompensation of kokanee losses is more accurately a function of present lake product vity rather than just replacement of pre-impondment loss estimates

COMPENSATIO

In the late 1970's, a compensation agreemen was signed by the Ministry of Environment and BC Hydro to provide funding to r place fish and fish habitat lost due

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