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HomeMy WebLinkAboutStudy of Fish Protection Methods Related to a Potential AK Hydro Develop 1983... .; .... ~ . . u j_ - ~OS66 B'tSBIV •a6BJ040UV ·af\'v 4lS "M v££ ~!J04ln'V J9MOd B'tS'BI V .:JO Olcan.t ---- ... . -- ~00 111 H.&JMioat r - - - - JJ.YCI I - ·sTUDY OF FISH PROTECTION METHODS RELATED TO A POTENTIAL ALASKAN HYDROPOWER DEVELOPMENT by Edward P. Taft III Stone & Webster Engineering Corporation Boston, Massachusetts and John S. Isakson Dames & Moore Seattle, Washington ABSTRACT B3-5311301-363 The Alaska Power Authority is investigating the feasibility of a hydropower development on the Newhalen River near Iliamna, Alaska. Since the river sustains a large run of sockeye salmon, concern has been expressed over the potential loss of outmigrants (fry and smolts) as a result of passage through the project. Consequently, preliminary plans have been made to incorporate a combined fish diversion and collection system into the power canal to intercept fry and smolts for safe return to the river. In order to obtain preliminary information on the potential effectiveness of the fish protection system, a series of fish diversion and impingement survival studies was conducted in June 1983, on the Newhalen River. The studies were conducted in a 4 ft x 4 ft x 8 ft test flume. Sockeye salmon fry (28-32 mm) and smolt (100-120 mm) were evaluated. Fish .Q_iver~on ~sts-were conducted with a 1.0 mm screen_ set at a 25 degree angle to the approach flow. Approach velocities ranged from 0.3 to 1.4 ft/sec. Smolt were observed to have no difficulty in maintaining orientation at the highest velocities and diverted without problem. Fry did not display diversion behavior except at the lowest velocities tested. I~ingement tests were conducted using a partitioned box insert, containing d!!_ferent mesh sizes (0_,_5, 1_!_0, ~0 mm), which was secured in the test flume. Fry were impinged on the 1.0 and 2.0 mm meshes for periods of 8 and 16 minutes and were then -held for-48-hour latent survival tests. Confingency table analyses indicated no significant differences in survival between the four test conditions. Mean survival at 48 hours was 93 percent. r;t~~_!l_control survival was also 93 perc«:nt. These preliminary results indicate that a combined fish diversion and collection system offers the potential for preventing losses of sockeye salmon fry and smolts at hydropower developments. 1 STOMa 81 WaBSTIER .A .. B3-5311301-363 INTRODUCTION The Alaska Power Authority is investigating the feasibility of a hydropower development <>n the Newhalen River near Iliamna, Alaska. As preliminarily planned, this project would entail the diversion of water into a high level canal at River Mile 7 in which it would flow to a powerhouse near the river mouth. Since the Newhalen River sustains a large run of sockeye salmon, concern has been expressed over the potential losses of outmigrants (fry and smolts) as a result of passage through the project. Consequently, preliminary plans have been made to intercept fry and smolts entering the canal and safely return them to the river. A combined fish diversion and collection system is envisioned using angled, traveling water screens (Figure 1). Such screens have been used successfully in both ca'pacities at a number of locations. By angling the screen to the flow and supplying a bypass at the screen terminus, hydraulic conditions are created which direct swimming· fish downstream and into the bypass. Fish with little or no swimming ability (i.e., early life stages) impinge on the screen. By continuously rotating the screen, the impinged fish are carried. vertically to a low-pressure spraywash which gently rinses them into a trough. This trough then flows by gravity and connects with the screen bypass line. Once connected, diverted and collected fish are returned via pipeline to a safe release location. In order to obtain preliminary information on the potential effectiveness of the fish protection system, a series of fish diversion and impingement survival studies was conducted in June 1983, on the Newhalen River (River Mile 13). MATERIALS AND METHODS The studies were conducted in a 4ft x 4ft x 8ft test flume. This flume was used for both diversion and impingement tests. For diversion testing, an insertable screen panel was fabricated (Figure 2). The panel incorporated 2.0 mm plastic mesh as the diversion medium. The panel frame was designed to fit into the flume at a 25 degree angle to the approach flow with accurate alignment of the downstream end of the frame to a stationary bypass wall. The bypass was 6 in. wide, full depth and 2 ft. long and discharged directly to the river. At the upstream end of the flume, a 5.0 mm mesh panel was placed across the flume entrance to contain test fish within the flume and to block the passage of larger debris. By allowing this screen to slowly foul with debris, it was found that less-than-maximum velocities could be achieved in the flume. Thus, the screen became a simple means for regulating flume velocity. For impingement tests, the diversion panel was removed and a segmented box was inserted across the width of the flume. The four segments were about 1 ft. wide and incorporated 0.5, 0.5, 1~0 and 2.0 mm plastic mesh, respectively (Figure 3). Testing was conducted with the 1.0 and 2.0 mm meshes only since these sizes are the minimum that would be required to retain even the smallest fry which might be enc.ountered. A 5. 0 mm 2 , .. ) / B3-5311301-363 plastic mesh was attached to the front of the entire box which contained the test fry within the appropriate test segment. For all testing, the flume was submerged in the river near the shoreline to a depth of about 18 in. Given available river flows at the selected location, a mean cross-sectional velocity of about 1.1 ft/sec was achievable with the angled screen in the flume (Figure 4). Locating the flume in a higher velocity area was not deemed desirable for these preliminary studies due to the difficulty in securing it firmly with anchoring devices. The selected location also resulted in relatively uniform and replicable flow conditions (Figure 5). All test fish were collected at the flume site with 9ft x 9ft wingless fyke nets (smolt) and an inclined plane trap (fry). Fish were generally tested within one day of capture. Prior to testing., they were held in tanks (smolt) or a netted box (fry) submerged in the river. Testing of the angled screen was conducted with both fry and smolt. Since smolt were capable of swimming easily against the maximum velocity achievable in the flume (approximately 1.3 ft/sec), all tests were conducted at this velocity. Fry, on the other hand, displayed little ability to guide along the screen at this velocity and were, therefore, tested at approach velocities as low as 0.5 ft/sec. Few smolt were available for angled screen testing. Further, the fish were obviously capable of maintaining their position in the flume at the velocities tested and easily avoided impingement on the screen. Therefore, for these preliminary studies, efforts concentrated on observing behavior for input to future studies rather than gathering extensive quantitative data. Unlike smolt, fry appeared to have difficulty diverting on the screen even at low velocity. In general, more than 50 percent of the fry impinged immediately upon release while the others diverted to the bypass. Eventually, the impinged fish worked their way along the screen and bypasse.d, usually within several minutes. It appeared that the fry had the ability to orient into the current and swim against even relatively high velocities. However, they did not react as strongly to the screen as might have been expected. Since fry impingement rates were high and the need for a collection type of screen was evident for this life stage, diversion testing again concentrated on observation of behavior rather than collection of quantitative data. As stated, impingement survival tests were conducted with 1.0 and 2.0 mm meshes. Although little was known about the survival potential of sockeye fry, it was believed that they would be relatively hardy. Therefore, early tests were conducted for impingement durations of 8 and 16 minutes. Since these durations initially resulted in low mortality, all further tests were conducted similarly. Every attempt was made to maintain the highest possible velocity through the test screen panels. However, velocities generally decreased slightly over the duration of the test due to debris clogging. Velocities at the beginning of each test ranged from 1.2 to 1.5 ft/sec; by the completion of a test, the velocity had decreased by no more than 0.2 ft/sec. 3 B3-5311301-363 At the time of each impingement test, two lots of about io fry were placed in a release container. The test screens were cleared of debris and a rubber mat was placed across the front of the two test chambers to stop the flow. The fish were then released into the 1. 0 and 2. 0 mm screen segments and the rubber mat was immediately removed causing the fry to impinge across the surface of the two meshes. After the desired test duration, the mat was again placed across the test area to restrict the flow. Fry were observed immediately for signs of stress or injury and were then removed to a holding area for observation of latent (48 hour) survival. For each day's experiments,. a control group of fry was held for comparison of 48-hour mortality -with test fish. The controls were treated in exactly the same manner as the test fish but were not subjected to impingement. The latent survival holding facility consisted of a flow-through water bath in which 4-in. diameter holding cups with mesh-covered bottoms were placed to hold test and control fry. Each group of about 20 test or control fish was split equally between two cups to avoid crowding. Initial mortality observations were made one hour after each test. This short delay allowed stunned fish to recover or die. Thereafter, mortality was recorded at 6, 12, 24 and 48 hours. After 48 hours, all remaining live fish were enumerated and returned to the river. RESULTS Results of diversion tests with smolt (100-120 mm) clearly indicated that these fish are capable of easily swimming against the velocities tested. Upon release into the flow, the smolt distributed across the flume; some diverted within several minutes to the bypass while others remained in the flume for up to several hours. It appeared evident that smolt should be very effectively diverted by an angled screen system. Diversion tests with fry (28-32 mm) indicate that this life stage did not respond strongly to angled screen under the conditions ·tested. At a velocity of 1. 0 ft/sec, most of the fry impinged on the screen upon release but gradually worked their way to the bypass. Impingement was random relative to fry orientation (i.e., head first, tail first, upside down,· etc.) indicating that the fish were generally overcome by the current without being able to orient into it. Similar results were noted with fry at 0.9, 0. 7, 0.6 and 0.6 ft/sec velocities. However, as the velocity decreased, more fish were able to divert to the bypass without impingement. Nonetheless, even at 0.5 ft/sec, some impingement was noted. In future studies, attention should be placed on determining the survival of diverted fry to evaluate the effects of possible abrasion on the screen. Results of fry impingement tests are summarized in Table 1. Mean survival at the mesh size/impingement duration combinations tested ranged from 87.3% to 95.8%. Contingency table analyses indicated no significant differences in survival between the four test conditions. Therefore, the data were combined to yield an overall mean survival value of 93 .1%. 4 STONII! a WKBSTII!IIt B3-5311301-363 Since the mean control survival was 93.4%, the differential mortality between test and control fish was essentially zero. Therefore, it would be expected that the potential for sockeye salmon survival in a screening system involving impingement and removal to a return location in the river is very high. Based on the results of these preliminary studies, it appears that fish diversion and impingement could be very effective in protecting sockeye salmon out-migrants at the potential Newhalen Hydropower project. Further studies are planned to develop this fish protection concept to a more detailed level. SUMMARY AND CONCLUSIONS 1. Sockeye salmon smolts) appear to have the capability for complete diversion in an angled screen system at low velocities (1.1 ft/sec). l -'} 2. Further studies are needed to quantify smolt diversion and survival at velocities higher than 1.1 ft/sec. 3. Sockeye fry are not capable of diverting effectively along an angled screen, even at low velocities; therefore, in order to protect fry, a collection system would be required; tjle possible effects of. ~rasion on an angled screen amo~-~ wh!__c:=!!_ __ ~o. ~~.t:~.J~.ipt to guide suould be investigated. 4. Sockeye ~ are capable of withstanding impingement on a fine-mesh screen (1.0 and 2.0 111111) with very high survival at relatively low velocities. Higher approach velocities in a power canal on the. Newhalen River would reduce costs. Smolt appear to have the potential for diverting at high velocity. Sim~larly, it would appear that fry could survive impingement at substantially higher velocities than those evaluated to date. Further, high velocities would act to minimize potential delays in migration as a result of the screening system. Therefore, further investigations of the angled screen diversion/collection system should concentrate on diversion and impingement survival at high velocities. B3-5311301-363A TABLE 1 SUMMARY OF TEST RESULTS A. Mean survival at each test condition B. c. D. E. Impingement Duration Mesh Size 1.0 mm 2.0 mm Mean overall test Mean survival for Duration: 8 16 Mesh Size: 1 2 8 min . . 9444 (n=6) .9583 (n=5) survival = .9313 each duration and mesh min. = .9558 min. = .9071 mm = .9064 mm = .9627 Mean control survival = .9343 Mean differential mortality size 16 min. .8725 (n=5) .9505 (n=4) Differential Mortality = Test mortality -Control mortality = (1.0-.9313) -(1.0-.9342) = -.0029 or 0 STONE 81 WltaSTitA ~ J _,_ FL. OW FISH BYPASS TO FISH REMOVAL .... ..==:--~ FACI~ITIES .. FIGURE 1 FL. OW TO Pt.M'S ~ CONCEPTUAL ANGLED SCREEN DESIGN ANGL.ED TRAVEl.. I NG SCREEN ( TYP) CENTER PIER s" WIDE BYPASS FLOW \ NEWHALEN 5mm INFLOW J RIVER SCR~~l------------ 1 ;' ~/ , 1 , 1 I I I l 1 1// I , , FIGURE 2 I /• , , 2mm ANGLED SCREEN ANGLED SCREEN FLUME ARRANGEMENT (PLAN) STONE 6 WEBSTER £. • FLOW I 5mm RETENTION SCREEN --------- ~ c:::I(J ~ ~ ,_.__ ------ 2.0mm l.Omm 0.5mm 0.5mm FIGURE 3 PLAN VIEW OF FLUME WITH IMPINGEMENT TEST CHAMBER INSERTED (PLAN) IMPINGEMENT TEST CHAMBER INSERT STONE 81 WEBSTER .. . 10" \7 1.0!5 1.0!5 .... ""!!... 1.00 1.10 1.10 + + ---+ + :+ I l l 1 I l 1.0!5 1.10 1.07 1.10 1.10 +-----+ + + + I I 1 I I 1.00 1.0!5 1.00 0.97 1.10 + + + i + I I I I I 6" 12 11 J 12 •• 6" FIGURE 4 FLUME CROSS-SECTIONAL VELOCITY ( FT/SEC) DISTRIBUTION UPSTREAM OF ANGLED SCREEN WATER -DEPTH 20" STONE & WI:B8TIER ~ .. _._.,........ ____ -------- QSO + 0.6 + FLOW • , 0.60 + 0.60 i'" 0.!0/ 0.60 I + I I 0.55 + I , I 0.55 0.60 0.60 + + + FIGURE 5 VELOCITY DISTRIBUTION ALONG ANGLED SCREEN AT APPROACH VELOCITY OF. 0.6 FT/SEC (MEASUREMENTS TAKEN AT MID-DEPTH) STONE 81 WEBSTER .A ' j j • • Telecall Date: September 29, 1983 Telecall from Ole Mathison, University of Alaska Fisheries Research, Juneau RE: Bristol Bay Meeting Subject: Cannot attend meeting of October 3. However, says that if Pat Poe is there, he did not need be. Wants more direct involvement in the project work. Implied wants to contract directly with Alaska Power Authority or Stone & Webster Engineering Consultants. Subconsulting to Dames & Moore too indirect. Patti -mentions Sept. 30, that it may be worth a trip to Juneau to talk with him re: working for us. I express caution as we cannot afford to lose John Isakson with Dames & Moore. She agrees. 375/097 <XI.OS: OS I ~3. ~7~!L. ~