In cooperation with the Glen Canyon Dam Adaptive Management Program 

Science Plan for Future Experimental Beach/Habitat 

Building Flows Released from Glen Canyon Dam 

By Melis, T.S., Hamill, J.F., Andersen, M.E., Fairley, H.C., Topping, D.J, Draut, A.E., Rubin, D.M., Wright, S.A., Coggins, L.G., 

Gwinn, D.C., Ralston, B.E., Kennedy, T.A., Cross, W., Hall, R., Rosi-Marshall, E., and Vernieu W.S. 

Technical Work Group Review 

Draft: May 14, 2007 

U.S. Department of the Interior 

U.S. Geological Survey 
 ii

U.S. Department of the Interior 

DIRK KEMPTHORNE, Secretary 

U.S. Geological Survey 

Mark D. Myers, Director 

U.S. Geological Survey, Reston, Virginia 2007 

Revised and reprinted: 2007 

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Suggested citation: 

By Melis, T.S., Hamill, J.F., Andersen, M.E., Fairley, H.C., Topping, D.J, Draut, A.E., Rubin, D.M., Wright, S.A., 

Coggins, L.G., Gwinn, D.C., Ralston, B.E., Kennedy, T.A., Cross, W., Hall, R., Rosi-Marshall, E., and Vernieu 

W.S., 2007, Science plan for future experimental beach/habitat-building flows released from glen canyon 

dam: U.S. Geological Survey, Grand Canyon Monitoring and Research Center. 

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Although this report is in the public domain, permission must be secured from the individual 

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 iii

 
 1

1 Science Plan for Future Experimental Beach/Habitat 

2 Building Flows Released from Glen Canyon Dam 

3 By Melis, T.S., Hamill, J.F., Andersen, M.E., Fairley, H.C., Topping, D.J, Draut, A.E., Rubin, D.M., 

4 Wright, S.A., Coggins, L.G., Gwinn, D.C., Ralston, B.E., Kennedy, T.A., Cross, W., Hall, R., Rosi5 Marshall, E., and Vernieu W.S. 

6 Introduction 

7 This science plan describes potential monitoring and research activities to be conducted by 

8 the U.S. Geological Survey’s (USGS) Grand Canyon Monitoring and Research Center (GCMRC) 

9 in the event that the Secretary of the Interior approves a high-flow experimental release, or 

10 beach/habitat-building flows (BHBF), from Glen Canyon Dam in the future. The GCMRC has 

11 responsibility for scientific monitoring and research efforts for the Glen Canyon Dam Adaptive 

12 Management Program (GCDAMP; program). The program is a federally authorized initiative to 

13 ensure that the mandates of the Grand Canyon Protection Act of 1992 are met through advances in 

14 information and resource management. Because of the lengthy lead time required to plan and 

15 execute a BHBF experiment, the Adaptive Management Work Group (AMWG)—the Federal 

16 Advisory Committee under the program that provides recommendations to the Secretary of the 

17 Interior on the operation of Glen Canyon Dam—recommended that the GCMRC develop this 

18 science plan in anticipation of future BHBF experiments. This plan is designed to build upon 

19 existing understanding to inform managers about the efficacy of using high flows to conserve not 

20 only sediment, but also related resources in Marble and Grand Canyons; it is not intended to be a 

21 complete and comprehensive long-term experimental plan (LTEP), but might be considered as one 

22 of several subcomponents of any future LTEP for evaluating the influence of BHBF tests over a 

23 decadal timeframe. 

24 A BHBF, as defined by the 1995 Operation of Glen Canyon Dam Final Environmental 

25 Impact Statement (EIS), is a release of water from Glen Canyon Dam that is at least 10,000 cubic 

26 feet per second (cfs) greater than allowable peak discharge (30,000 cfs) but not greater than 45,000 

27 cfs. The EIS termed these experimental releases beach/habitat-building flows because they were 

28 intended to, at least in part, mimic predam floods that previously maintained sandbars and related 

29 habitat throughout the Colorado River ecosystem (CRE)—the Colorado River corridor from the 

30 forebay of Glen Canyon Dam to the western boundary of Grand Canyon National Park (figure 1.1). 

31 For the purpose of this science plan, these non-emergency high-flow dam releases shall be referred 

32 to as a BHBF or BHBF test. BHBF tests are considered bypasses or spills because they exceed 

33 normal powerplant capacity, and, to date, have been implemented only as tests to evaluate the 

34 degree to which beaches and sandbars can be maintained using this flow-only management 

35 strategy. 

36 

37 

38 
 2

1 

2 Figure 1.1. The Colorado River ecosystem encompasses the river corridor that extends from below 

3 Glen Canyon Dam to the western boundary of Grand Canyon National Park, Arizona. 

4 

5 Maintenance of sandbars in the CRE in the postdam era requires the periodic release of high 

6 flows from the dam to transfer sand from the channel into eddy-sandbar environments (Schmidt 

7 and others, 1999). In transferring sand to shorelines, BHBFs are known to form nearshore habitats, 

8 such as backwaters that structure the aquatic environment. BHBFs may also disadvantage 

9 nonnative fish (e.g., Minckley and Meffe, 1987), which are of concern because they are thought to 

10 compete with native species like the endangered humpback chub (Gila cypha) for food and prey on 

11 young native fish. Shoreline sandbar deposits that are built during BHBF tests are also sources of 

12 sand that can be transported by wind to areas upslope, which may protect archaeological resources 

13 from weathering and erosion. Conservation of sand resources, endangered humpback chub, and 

14 cultural resources found in the Colorado River ecosystem are primary goals of the Glen Canyon 

15 Dam Adaptive Management Program (U.S. Department of Interior, 1995; Patten and others, 2001). 

16 Although this science plan primarily focuses on potential experimental studies associated 

17 with future BHBF tests, the plan also addresses concerns expressed by GCDAMP participants 

18 about issues related to future high-flow experimental research, particularly the associated costs and 

19 benefits. Appendix A presents the issues of concern, relevant information about these issues 

20 gathered during the science-planning process, and responses prepared by GCMRC scientists. 
 3

1 Efforts have been made to identify the pros and cons of future BHBF tests, which are also 

2 enumerated in appendix A. 

3 Background 

4 The most pressing question that sediment researchers have been asked to address for the 

5 program is whether it is possible to restore and maintain sandbar habitats in the Colorado River 

6 ecosystem over the long term solely through the manipulation Glen Canyon Dam releases. As 

7 articulated in GCMRC’s strategic science plan (2007–11), the primary strategic science question 

8 driving sediment studies that justifies future BHBF testing is: 

9 

10 Is there a “flow-only” operation that will rebuild and maintain sandbar habitats over 

11 decadal timescales? 

12 

13 Despite continual advances in the understanding of the physical dynamics of the CRE that 

14 have accrued since the GCDAMP’s inception more a decade ago, existing information and models 

15 are not yet capable of answering this question. Scientists have concluded that answering the 

16 question will require a commitment to an ongoing program of BHBFs (i.e., short duration dam 

17 releases of between 41,000 and 45,000 cfs) implemented at perhaps the same frequency as annual 

18 average to above-average new sand is provided to the system by tributaries to the mainstem 

19 Colorado River. Although sediment scientists believe that is the only potentially successful option, 

20 one to several additional BHBF tests are still required to fully evaluate the approach. The rationale 

21 for conducting experiments under sediment-enriched conditions has been documented in several 

22 peer-reviewed outlets, including Webb and others (1999), Topping and others (2000a), Rubin and 

23 Topping (2001), Rubin and others (2002), Schmidt and others (2004), Wright and others (2005), 

24 Hazel and others (2006), Topping and others (2006), and Melis and others (2007). 

25 The sediment-related data that researchers propose to collect for future high-flow tests will 

26 facilitate comparison with the data collected for BHBFs conducted in 1996 and 2004. Proposed 

27 experimental studies will also generate new data that can be compared to previous tests on the 

28 physical processes regulating sandbar erosion and deposition during BHBFs, sediment deposition at 

29 archaeological sites, ecosystem flux measurements related to organic tributary inputs, effects of 

30 flood disturbance on vegetation, and formation of backwater habitats used by native and nonnative 

31 fishes. These comparisons must be made to determine whether greater and more geographically 

32 extensive sandbar rebuilding is possible with future BHBFs than occurred during the 1996 and 

33 2004 tests. The results have implications for native fish survival, cultural resource preservation, and 

34 habitat enhancement benefits for other high-priority aspects of the Colorado River ecosystem. Fully 

35 answering the strategic sediment science question posed above will obviously require additional 

36 data collection than proposed in this experimental science plan, and these additional data will likely 

37 only be collected during future monitoring activities, which could occur through 2009 and beyond. 

38 2004 High Flow Findings 

39 In September 2002, the U.S. Department of the Interior approved implementation of new 

40 BHBF testing on the basis of triggering thresholds linked to sand inputs from the Paria River. This 

41 new experimental strategy was adopted on the basis of new findings about CRE sediment-transport 

42 behavior following the 1995 EIS and the 1996 BHBF test that indicated the annual sand input from 

43 tributaries was not accumulating over multiyear periods under the modified low fluctuating flow 
 4

1 (MLFF) alternative (Wright and others, 2005). The new experimental paradigm focused on 

2 evaluating how effectively high-flow releases might be used to move new sand up onto shorelines 

3 before it was flushed downstream. The sand input trigger was specifically targeted to be a volume 

4 of sand from the Paria River that, on average, would occur about every other year. The only BHBF 

5 experiment conducted as a result of the Paria sediment trigger occurred in 2004. Significant sand 

6 inputs to Marble Canyon occurred during September–November 2004 and exceeded the sediment 

7 trigger. Approval of a supplemental environmental assessment paved the way for the BHBF test 

8 that began on Sunday, November 21, 2004. 

9 During the 2004 experiment, a net transfer of channel sand into eddies resulted in an 

10 increase in sandbar total area and volume in the upper half of Marble Canyon (Topping and others, 

11 2006). Further downstream, where sand was less abundant, the experiment resulted in the net 

12 transfer of sand out of eddies (Topping and others, 2006). Scientists also confirmed that substantial 

13 increases in total eddy-sandbar area and volume are only possible during high-flow releases 

14 conducted under the sand-enriched conditions that follow large tributary floods (Rubin and others, 

15 2002; Topping and others, 2006). In the future, more sand than the 800,000 to 1,000,000 metric16 tons of sand available during the 2004 BHBF test will be required to achieve increases in total 

17 eddy-sandbar area and volume throughout all of Marble and Grand Canyons (Topping and others, 

18 2006). 

19 Because tributary inputs of sand larger than those that preceded the 2004 BHBF test are 

20 relatively rare, it is not considered feasible to achieve significant systemwide rebuilding of sandbars 

21 with a single BHBF. Rather, the most promising method of rebuilding sandbars systemwide over 

22 the long term is by following each average to above-average tributary input of sand with a short23 duration BHBF (Topping and others, 2006a). Under this scenario, each subsequent BHBF test 

24 presumably builds upon the results of the previous one, potentially resulting in cumulative 

25 increases in systemwide sandbar area and volume over decadal time scales. However, this strategy 

26 is only feasible if the intervening powerplant releases do not completely erode the sand deposited in 

27 sandbars during these BHBFs. Since theory and monitoring data for this system have shown that 

28 fluctuating flows transport more sand than equivalent-volume steady flows, intervening releases 

29 with the least amount of fluctuation will have the highest probability of maintaining the sandbar 

30 building achieved during future BHBF tests. Hence, there is a long-term need for monitoring 

31 sandbar changes over a period of repeated BHBF tests under multiple sand enrichment scenarios 

32 (perhaps at least over a decade) to answer the core science question for sediment. This science plan 

33 assumes that sufficient long-term sediment monitoring will occur during 2008 and beyond, which 

34 will supplement BHBF test evaluations, to allow scientists to investigate the effects of dam 

35 operations that occur between BHBF tests. 

36 In terms of archaeological resources, earlier studies (e.g., Hereford and others, 1996; Draut 

37 and others, 2005) showed that many prehistoric cultural sites found in Grand Canyon are not only 

38 built on Colorado River flood deposits, but also are buried by windborne sand derived from river39 deposited sediment that has helped to preserve them over time. Results following the 2004 BHBF 

40 test confirmed that high flows released under sand-enriched conditions can increase the nearshore 

41 source areas for windborne sand, leading to increases in the rate of sand transported toward some 

42 locations in Grand Canyon that contain cultural resources (Draut and Rubin, 2006). Increased sand 

43 transport by wind and backfilling of gullies and deflated areas with aeolian sand can potentially 

44 reduce the rate of erosion and increase the preservation potential of these sites. 
 5

1 Summary of Key Findings from the 2004 BHBF Test 

2 

3 • Although substantially more sand was present in suspension in upper Marble Canyon during 

4 the 42,000 cfs 2004 BHBF test than during the 45,000 cfs 1996 BHBF test, there was less 

5 sand in suspension further downstream during the 2004 BHBF than during the 1996 BHBF 

6 (Topping and others, 2006). 

7 

8 • During the 2004 BHBF, net transfer of channel sand into eddies resulted in an increase in 

9 sandbar total area and volume in the upper half of Marble Canyon. Further downstream, 

10 where sand was less abundant, the response of eddy sandbars during the 2004 BHBF test 

11 was similar to that observed throughout Marble and Grand Canyons during the 1996 

12 BHBF—net transfer of sand out of eddies (Topping and others, 2006). 

13 

14 • Substantial increases in total eddy-sandbar area and volume (such as those observed in the 

15 upper half of Marble Canyon following the 2004 BHBF) are only possible during BHBFs 

16 conducted under the sand-enriched conditions that follow large tributary floods (Rubin and 

17 others, 2002; Topping and others, 2006). 

18 

19 • After the 2004 BHBF, where substantial flood sediment still remained until the subsequent 

20 spring windy season, windborne sand transport was significantly greater than in the 

21 previous spring given comparable wind conditions (Draut and Rubin, 2006). Sediment-rich 

22 BHBFs can increase windborne transport of sand toward some locations in Grand Canyon 

23 that contain archaeological material, thereby reducing gully erosion and increasing the 

24 preservation potential of these sites. 

25 Recommended Magnitude, Timing, and Duration of Future BHBF Tests 

26 Following the 2004 BHBF test, the sand input trigger was reevaluated by the GCMRC and 

27 the Science Planning Group (SPG) and revised to include sand inputs from the Little Colorado 

28 River (LCR) and other lesser tributaries in addition to the Paria River. The revised sediment trigger 

29 proposed for future BHBF tests would occur when 0.5 million metric tons of sand are introduced 

30 by the Paria River and retained above river mile (RM) 30 and an additional “weighted” 0.5 million 

31 metric tons of sand are delivered by the Paria and Little Colorado Rivers, or sources that enter the 

32 ecosystem annually in between these two primary tributaries and are retained upstream of Diamond 

33 Creek (RM 226). To calculate the weighted input, sand from the Paria River is given full value and 

34 sand from the LCR and other sources is valued at 50% of the actual input. Thus, a BHBF could be 

35 triggered with an input of 1.0 to 1.5 million metric tons of sand depending on how much of the 

36 sand is derived from the Paria River. The rationale for revising the sand input trigger is that it 

37 allows experimentation under enriched sand conditions that might occur below Marble Canyon 

38 from the LCR during periods when the Paria River inputs alone may not equal the earlier trigger, 

39 but weights the Paria River inputs over downstream inputs to prevent BHBFs from occurring at 

40 times when the Marble Canyon has not had any annual sand inputs. Under the revised triggering 

41 criteria, repeated experiments might occur more frequently and would facilitate a more rapid 

42 evaluation of whether or not cumulative sandbar deposition occurs on a systemwide basis through 

43 time. 
 6

1 Seasonal Timing: Considerations about Biology and Cultural Resources 

2 The optimal timing of future BHBF tests is dependent on the timing of tributary inputs as 

3 well as flow releases from the dam, which are in turn dependent on basin hydrology. The optimal 

4 timing for a BHBF in one year may not be the same as in another year. In general, the optimal 

5 timing is when the most new tributary-derived sand is available throughout the system. 

6 Historically, the largest Paria River inputs have occurred during the later summer and fall 

7 thunderstorm season. For the Little Colorado River, large inputs may occur during the late summer 

8 and fall thunderstorm season as well as during springtime floods. The rate at which the tributary9 derived sand is exported downstream to Lake Mead is dependent on the availability of the new sand 

10 as well as flow releases from the dam. Under moderate and higher dam releases the export rate can 

11 be quite high, which may constrain the time available for the new sand to be used for BHBF tests 

12 (Rubin and others, 2002). The majority of sand in a moderate input is predicted to be lost within 

13 days (at discharges of >35,000 cfs), weeks (at discharges of ~25,000 cfs), or months (at discharges 

14 of ~15,000 cfs); however, at discharge rates of 10,000 cfs or less sand is retained for periods of 

15 months to years. As discussed previously, the new sand will only be available for BHBF tests, if the 

16 BHBF occurs shortly after new sand enters the system or if dam releases are constrained; however, 

17 as noted above, basin hydrology may prohibit low releases. 

18 Because of this interaction between the timing of tributary inputs and basin hydrology, the 

19 optimal timing of BHBF tests will vary from year to year. For example, during periods of wet 

20 hydrology and high dam releases, when export rates are expected to be high, the optimal time to 

21 conduct BHBF tests would likely be within days or weeks of large tributary inputs such as during 

22 late fall for typical Paria inputs. Conversely, during periods of dry hydrology and low volume dam 

23 releases, when export rates are expected to be lower, it may be optimal to wait until later in the 

24 winter or early spring, which will allow sand from the Paria and Little Colorado Rivers to 

25 accumulate throughout the various sediment input seasons. Finally, export rates are dependent on 

26 the amount of fluctuation as well as the total volume; thus, the amount of fluctuation will affect the 

27 amount of sand available and the optimal timing of BHBF tests (i.e., less fluctuation leads to more 

28 retention and thus more flexibility in BHBF timing). 

29 Peak Flow Magnitude 

30 Consistent with the 1995 EIS (U.S. Department of the Interior, 1995), as well as previous 

31 BHBFs in 1996 and 2004, future tests should be conducted in the range of 41,500 to 45,000 cfs, or 

32 possibly higher when Lake Powell storage is high enough to reach the spillway gate elevations, to 

33 promote the most robust conservation of sand at higher elevations along the river banks. 

34 Replication of the 2004 peak magnitude of 41,500 cfs during future BHBF tests has the most 

35 likelihood for supporting comparative analyses intended to determine the potential for using sand36 enriched high flows to build and maintain sandbar habitats.

37 Peak Flow Duration and the Lag Time Phenomenon 

38 The concept of replicating the 2004 BHBF test hydrograph was discussed extensively 

39 among cooperating sediment scientists at the 2005 knowledge assessment workshop convened by 

40 the GCMRC with stakeholders. The 2004 test hydrograph was designed on the basis of sandbar 

41 simulations for a subset of eddies under a scenario of 45,000 cfs peak magnitude and sand 

42 concentrations that were measured in the postdam era. This, along with data collected from the 

43 1996 BHBF test, was the basis for choosing 60 hours as the reduced duration for peak flow, which 
 7

1 is down from 168-hour test that occurred in 1996. The 2004 peak magnitude was limited to 41,500 

2 cfs because one of the eight units at Glen Canyon Dam was undergoing maintenance. Replication 

3 of the 2004 hydrograph in a future test seeks to determine if the locally robust and consistent 

4 sandbar building responses that occurred in upper Marble Canyon as the result of the 2004 BHBF

5 test will occur consistently. Scientists will also examine the downstream progression of sandbar 

6 building each time a BHBF is released under locally sand-enriched conditions. By reproducing the 

7 2004 test hydrograph in future BHBF tests, scientists would also be able to evaluate if there are 

8 cumulative benefits to sandbar conservation in lower Marble Canyon and Grand Canyon each time 

9 sand-enriched BHBFs occur. 

10 The GCMRC and its science cooperators recently evaluated the limitations and benefits of a 

11 shorter duration peak at 41,500 cfs, such as one that lasted for only 30 hours. Exact predictions 

12 about the outcome of a BHBF with a shorter duration are not possible at this time without field 

13 experimentation. Predictability is limited because current sediment models have limited utility in 

14 making such predictions and there are many factors to consider related to peak-flow duration and 

15 peak magnitudes for high-flow experiments. While the main recommendation from scientists at 

16 present is to use the same hydrograph for the next test as was used in 2004, they also acknowledge 

17 that future BHBF tests with durations of not less than 30 hours would also provide sufficient data 

18 collection to advance learning about BHBFs and sediment dynamics. In table A.2 of appendix A the 

19 GCMRC compares of the pros and cons associated with a 60-hour versus 30-hour peak high-flow 

20 test duration. 

21 By conservation of mass, flood waves in a wet channel travel downstream at a higher 

22 velocity than the water (Lighthill and Whitman, 1955). Additionally, the water travels much faster 

23 than the sand in suspension. Thus, depending on the longitudinal distribution of sand in the river, 

24 substantial lags may develop between a BHBF flood wave and the sand in transport, with the flood 

25 wave greatly leading the suspended sand. During the 2004 BHBF test, this disparity in travel time 

26 between the flood wave and the water and new sand input from the Paria River was as much as 27 

27 hours by the time the flow peak reached Diamond Creek, more that 240 river miles below Glen 

28 Canyon Dam. During evaluation of the flow and sediment data from the 2004 test, it became 

29 apparent that once the peak of the test release had moved ahead of the new sand supply in upper 

30 Marble Canyon, it became another test of the 1996 BHBF test, except with even less sand available 

31 in downstream reaches owing to continued sand export between 1996 and 2004. 

32 Although the fall 2004 dam releases that preceded the 2004 BHBF test (5,000 to 10,000 cfs 

33 daily range) were very effective in limiting downstream sand transport between September and late 

34 November 2004, having the new sand mostly stockpiled in the upper section of Marble Canyon 

35 meant that the flood wave’s higher velocity took it downstream of the new sand supply by the time 

36 the flood reached lower Marble Canyon and beyond. As a result, sediment scientists now suggest 

37 the need for some period of normal dam operations following the input of new sand to allow some 

38 redistribution of new sand before to conducting future BHBF tests. Allowing the sand to be 

39 redistributed before a BHBF test might produce more optimal sandbar building than occurred 

40 during the 2004 test. The hypothesis to test here is that a more uniformly distributed new sand 

41 supply will be more evenly transferred to eddy sandbars throughout this critical upper Canyon 

42 reach as the fast-moving flood wave propagates downstream. If the results from replicating the 

43 2004 hydrograph under sand-enriched conditions in the spring following one to several months of 

44 downstream sand transport under Record of Decision operations are as positive as those measured 

45 in 2004, then this approach may be interpreted as being a sustainable strategy for longer term 

46 habitat rebuilding and maintenance (see figure 1.2). Positive in this case means that the BHBF test 
 8

1 produces more uniformly distributed sandbar responses under conditions of more uniformly 

2 distributed sand supply downstream or deposition progressing farther downriver with successive 

3 floods as upriver eddies become filled. 
 9

1 

2 

3 Figure 1.2. Flow chart for evaluating future BHBF test results intended to test the concept of “flow 

4 only” operational treatments combined with tributary sand supplies below Glen Canyon Dam to 

5 restore sandbar habitats and related resources. If available sand can be increased 

Yes 

No

No

Conduct replicated1 BHBF test under 

sand triggers – measure changes in 

eddy-sandbar area and volume for each 

event 

Measure changes in eddy-sandbar area 

and volume during intervening 

operations 

Are gains during BHBF tests 

exceeding loss(es) during 

intervening operations? 

Are gains in eddy-sandbar area 

and volume meeting 

management objectives? 

Evaluate options for increasing 

available sand, such as changing 

intervening operations and/or 

mechanical augmentation 

Yes

Conduct additional 

studies to optimize 

BHBF timing, frequency, 

and hydrograph shape 1 Replication implies use of a similar BHBF test hydrograph to 

November 2004, recognizing that it is impossible to replicate the 

exact initial conditions (i.e. tributary sand inputs are controlled by 

nature). Replication of the hydrograph allows for more direct 

comparison between events and also serves as a monitoring tool to 

help evaluate whether or not sand resources are improving. 
 10

1 Integrating Research and Monitoring for Future BHBF Research Studies 

2 Previous BHBF tests in 1996 and 2004 consisted of several physical, biological, and 

3 sociocultural studies; however, these studies were not fully coordinated to achieve objectives for 

4 integrating data and interpretive results. Developing a more integrated research and monitoring 

5 program in the future is a major goal of the GCMRC during the next phase of its strategic science 

6 initiative (2007–11). Several science planning meetings between GCMRC scientists and 

7 cooperators in 2006 resulted in a more integrated study plan than those associated with previous 

8 BHBF experiments. For instance, sediment studies have been more closely integrated between 

9 suspended-sediment flux measurements, eddy sandbar and flow and sand deposition measurements, 

10 and modeling activities. Further, sociocultural elements and objectives related to the fate of new 

11 sandbars following a BHBF test, particularly with respect to secondary aeolian transport into 

12 archaeological sites (tied to better meteorological data), have been integrated into the core sediment 

13 study plan (see linked elements of experimental studies 1.A, 1.B, and 1.C). 

14 Links between sediment and biological studies are also highlighted. For example, this 

15 science plan includes closely coordinating the study of riparian vegetation dynamics with sandbar 

16 sedimentology and fine-sediment flux data (see experimental study 2). Efforts to explore how 

17 BHBFs affect lower trophic levels (experimental study 3) has several study components, each of 

18 which is intended to interface with sediment project components. In particular, experimental study 

19 3 is concerned with studying the fate of organics, the tributary derived debris (wood, seeds, and 

20 other organic materials) that enters the ecosystem with sediment inputs, and its movement through 

21 the river corridor. Previous studies have documented that much of this organic carbon becomes 

22 deposited within new sandbar deposits that may persist in buried beaches for extended periods, but 

23 none of the previous research has been linked to whole system carbon budgets. This information 

24 will be critical for ultimately measuring the effect of BHBF tests on inputs, retention, and export of 

25 organic matter that fuels river food webs. 

26 In several cases, the experimental studies proposed here have also been coordinated with 

27 ongoing monitoring efforts, such as the systemwide inventory of backwaters that occurs each 

28 September to sample these habitats for fish presence and abundance (work consistently repeated 

29 each fall since 2002). Future inventories of backwaters will provide valuable distribution, size, and 

30 abundance data about fish using these habitats within several months of future BHBF tests. 

31 The Grand Canyon fish community is actively monitored annually. This information helps 

32 evaluate the impacts of BHBF tests on this resource. Scientists at the GCMRC are actively working 

33 on additional methods to help further evaluate the fish community before and after BHBF tests (see 

34 appendix C). Experimental study 4.A is focused on nonnative rainbow trout, but the study also 

35 includes the involvement of physical scientists and flow modeling to answer questions about how 

36 high flows transport gravel in the Lees Ferry reach, a process that could have implications for redd 

37 mortality and recruitment of nonnative fishes that might influence downstream predator/prey and 

38 competition interactions between humpback chub and salmonids. Finally, experimental study 5 

39 attempts to document changes in Lake Powell and resultant downstream quality of water; data that 

40 is intended to inform productivity studies associated with experimental study 3. 

41 Experimental Studies 

42 This science plan describes the suite of additional research and monitoring activities thought 

43 to be desirable, feasible, and necessary to interpret and understand the effects of conducting BHBF 

44 tests during sand-enriched conditions on key CRE resources. The experimental studies presented in 
 11

1 this plan are designed to explore and possibly answer a number of scientific questions that are 

2 priority concerns identified by the Adaptive Management Work Group (table 1.1). In some cases, 

3 current technologies and methods were found to be inadequate for answering these priority 

4 questions, such as predicting the influence of future BHBF tests on native fish populations. 

5 Appendix B identifies ongoing monitoring and research activities associated with various 

6 resources, the challenges that confronted scientists in attempting to develop this science plan, and 

7 other considerations that influenced the selection of the experimental studies identified here. 

8 Table 1.1 Scientific questions identified as a priority by the Adaptive Management Work Group 

9 SEDIMENT 

10 • Is there a “flow-only” operation that will restore and maintain sandbar habitats over decadal timescales? 

11 • What is the minimum duration for BHBFs needed to build and maintain sandbars under sand enrichment? 

12 • Do sandbars deposited by BHBFs contribute to preservation of archaeological sites in the river corridor? 

13 • How do post BHBF flows affect the persistence of sandbars and related backwater habitats? 

14 HUMPBACK CHUB 

15 • Do BHBFs result in creation of nearshore habitats (i.e. backwaters) that can offer physical benefits to 

16 humpback chub and other native fishes? 

17 • Do BHBFs affect the distribution and movement of nonnative fishes? 

18 • What are the effects of BHBFs on aquatic food production? How do these effects impact native fishes? 

19 CULTURAL RESOURCES 

20 • Do sandbars deposited by BHBFs contribute to preservation of archaeological sites in the river corridor? 

21 • Do BHBFs contribute to added stability or erosion of archaeological sites located in close proximity to the 

22 river? 

23 • How does the abundance and distribution of native and nonnative riparian species important to Native 

24 American tribes change in response to a BHBF? 

25 RAINBOW TROUT 

26 • Are individual rainbow trout displaced from the Lees Ferry reach as a result of a BHBF? If so, do displaced 

27 rainbow trout return to the reach, or do they establish residence elsewhere? 

28 OTHER PRIORITY ISSUES 

29 • Food base: How do BHBFs affect food production and availability for rainbow trout in the Lees Ferry reach? 

30 • Lake Powell: Will BHBFs result in higher nutrient releases and shrinking of the hypolimnion? Will the 

31 operation of the river outlet works and the penstocks at capacity measurably alter Lake Powell hydrodynamics 

32 or stratification, or alter release water quality? 

33 • Riparian vegetation: Are open patches more susceptible to exotic species colonization and establishment 

34 than sites with existing vegetation following a disturbance?

35 • Kanab ambersnail: Will BHBFs reduce habitat at Vaseys Paradise in a way that impacts the ambersnail 

36 population? 

37 • Camping beaches associated with sandbars: Can BHBFs increase campable areas at sandbars on a 

38 sustainable basis? 

39 

40 

41 
 12

1 The experimental studies presented in this science plan also recognize that resource 

2 responses are driven not only by the physical effects of the high flows but also by interrelation 

3 among resources. As a result, this plan integrates the evaluation of the high-flow effects across 

4 multiple resources. 

5 The experimental studies identified below are in addition to or represent an expansion of 

6 ongoing research and monitoring activities typically included in the GCMRC’s annual work plans. 

7 The implementation of research and monitoring activities associated with proposed experimental 

8 studies will represent a substantial undertaking by the GCMRC, cooperators, and contractors. To 

9 adjust to the increased workload that occurs in years when BHBF tests take place, the GCMRC 

10 proposes to increase the activities of existing contractors and cooperators and add additional onsite 

11 contractors to the degree feasible and affordable and to temporarily add technical staff to existing 

12 projects. When essential, new agreements and contracts would also be established for appropriate 

13 periods to accomplish the new research related to BHBF tests. Clearly the additional personnel, 

14 equipment, and supply costs associated with a BHBF test will require additional funding. 

15 A description of each proposed experimental study follows, including the program goals 

16 and management objectives each study is designed to advance and the projected cost of each 

17 activity. Each study description includes a section that identifies links to other studies that are 

18 designed to promote integrated, cross-disciplinary science collaborations and outcomes. 

19 These studies are briefly summarized along with estimated costs in table 1.2. 
 13

1 Table 1.2 Summary of proposed studies and estimated costs associated with future integrated beach/habitat-bu2 tests. 3 

BHBF Related Science Projects Goal Associated with Study Hypotheses 

SEDIMENT/CULTURAL STUDIES  A - Sand Budgeting B - Sandbar Depositional Rates C.1 - Sandbar Fate: Topographic and Grain-size Responses  C.2 - Sandbar Fate: Effects of new Sand Deposits at Cultural Sites 

A – Sand Budgeting: (1) reach-based accounting of input vs. export during the BHBF test, (2) longitudinal patterns of erosion and deposition of sand, and (3) changes in sediment grain size related to enrichment/depletion of sand. B – Sandbar Deposition Rates: Improve understanding of time evolution of eddy sandbars and rate of deposition or erosion of eddy sandbars during BHBFs to determine optimal BHBF peak duration necessary to achieve management goals. C – Sandbar Fate: (1) determine if BHBFs conducted under sedimentenriched conditions can maintain/sustain eddy sandbars and 

A - Sand Budgeting: BHBFs with sand enrichment similar to the 2004 test will result in bar building comparable to that observed during the 2004 BHBF test. If true, then sand budget will be positive between rivermiles 0 and 30 for the period bracketing the tributary inputs of sand and the BHBF test. If reaches downstream from river-mile 30 are sand-enriched relative to the 2004 test, then bar building in these reaches will be greater than was observed in these reaches during the 2004 test and the sand budgets in these reaches will also be more positive than in 2004. B - Sandbar Deposition Rates: Sand deposition rates during BHBFs are regulated by (1) interaction of the flow field with the antecedent bed topography and (2) the upstream sand supply. At a given location and for a given BHBF hydrograph, sandbars grow over time if upstream sand supply is sufficiently large; conversely, if upstream sand supply is insufficient, then sandbars will erode. C.1 - Sandbar Fate: BHBF tests under sand enrichment like those prior to the 2004 test result in bar building and low-elevation gully infilling 

A&B - S

C - Sedim
 14

 C.3 - Sandbar Fate: Changes in Campable Area 

campsites, and (2) whether increased aeolian flux of sand from larger sandbars produced during sandenriched BHBFs can maintain downwind (but upslope) archeological sites. 

comparable to that observed during 

2004 test. C.2 - If reaches downstream from river-mile 30 are more sand-enriched compared to pre-2004-test conditions, then bar building and gully infilling in these reaches will be greater than was observed in these reaches during the 2004 test. C.3 – Larger, dry sandbars will result in increased aeolian flux of sand to downwind archaeological sites, thereby increasing their preservation potential. 

AQUATICS - FISH AND FOOD STUDIES Fish –  A - Lees Ferry Reach Rainbow Trout Redds Studies  B – Rainbow Trout Movement Studies in Glen and Marble Canyons Food Production -  - BHBF effects on lower trophic 

Fish A - Determine how high flows affect spawning survival of early life history stages of rainbow trout in the Lees Ferry reach. B - Determine if a BHBF causes displacement of rainbow trout from the Lees Ferry trout fishery into Marble Canyon and Grand Canyon B - Determine if such displacement is experienced differentially among different length fish B - Provide a platform for Grand Canyon scientists to develop skills with acoustic technologies that can be applied to answering questions about native and nonnative fish movement, distribution, and sampling efficiencies. Food Production To determine whether a BHBF has a 

Fish A - High flows will scour redds but the effect on the juvenile rainbow trout population will be limited because of compensatory survival responses. A - High flows will alter the distribution of age-1 fish in the Lees Ferry reach resulting in either higher mortality or migration out of the reach. B - BHBF will result in displacement of trout from the Lees Ferry reach into Marble Canyon and Grand Canyon. B - The redistribution of trout will be inversely related to size Food Production A short duration BHBF in spring 

Fish: ~$1Food Pro
 15

levels (i.e., algae and invertebrates) in the Colorado River ecosystem 

neutral, negative, or positive effect on the quantity and quality of food available for invertebrates, and ultimately fishes. 

initially scours the river bottom causing reductions in algal biomass, but the new algal community is of higher quality, more productive, and is assimilated more efficiently by invertebrate consumers, leading to an increase in annual invertebrate production. 

OTHER STUDIES Native/nonnative diversity and richness - Lake Powell: Influence of BHBF on Lake Powell QW 

Native/nonnative diversity and richness – Compare native/nonnative diversity in established and reworked depositional environments along a hydrological gradient following a high-flow test. Lake Powell – Determine how BHBF will alter QW in tailwaters of GCD and Lake Powell fore bay 

Native/nonnative diversity and richness – Native/nonnative species richness ratios are the same across all habitats and surface elevations. A: The ratio between native/nonnative richness and cover at established sites will not change following disturbance Bare areas will have similar ratios Surface elevation will not have an affect on native/nonnative richness and cover values. B: The ratio between native/nonnative richness and cover at sites with established vegetative communities will shift toward an increase in nonnatives due to the increased nutrient availability associated with the disturbance. Native/nonnative richness and cover ratios will change by surface elevation with nonnative species decreasing with increasing surface elevations in relation to available soil nutrients. Bare areas will favor nonnative species across all surface elevations. Lake Powell – BHBF will result in higher nutrient releases and shrinking of the hypolimnion 

Seed DisLake Pow
 16

CONSERVATION MEASURES  - Kanab Ambersnail Habitat  - Archeological Sites Public Outreach Activities 

KAS – habitat at Vaseys Paradise Arch Site Mitigation – Glen Canyon site 

N/A N/A N/A 

KAS: ~$Cultural Public OTOTAL 

1 
 17

1 Part 2: Experimental Study Descriptions 

2 

3 

4 Experimental Study 1.A: Reach-scale changes in the fine-sediment 

5 mass balance and grain size during BHBF Tests 

6 

7 Duration 

8 

9 20 months 

10 

11 Principal Investigator(s)

12 

13 David Topping, USGS WRD-National Research Program, and David M. Rubin, USGS 

14 GD-Western Coastal and Marine Geology 

15 

16 Geographic Scope 

17 

18 River miles 0 through 226

19 

20 Project Goal(s) 

21 

22 This project documents the following: (1) reach-based sediment budgeting during future 

23 BHBF tests, (2) longitudinal patterns of net erosion and deposition of sand, and (3) 

24 temporal and spatial changes in sediment grain size related to enrichment/depletion of 

25 sediment during future BHBF tests. 

26 

27 Need for Project 

28 

29 Detailed measurements of sediment flux and grain size are required to evaluate whether 

30 one or more future BHBF tests conducted under sand-enriched conditions can be used to 

31 maintain/sustain eddy sandbars in the Colorado River ecosystem. These data are also 

32 required for continued development/verification of predictive physically based sediment33 transport models. 

34 

35 Strategic Science Question(s)

36 

37 4.1 Is there a “Flow-Only” operation (i.e. a strategy for dam releases, including 

38 managing tributary inputs with BHBFs, without sediment augmentation) that will 

39 rebuild and maintain sandbar habitats over decadal time scales? 

40 

41 Working Hypotheses 

42 

43 Future BHBF tests conducted under magnitudes and longitudinal distributions of sand 

44 enrichment similar to those that existed before the 2004 BHBF test will result in sandbar 

45 building comparable to that observed during the 2004 BHBF test. If this is the case, the 

46 sand budget computed under this project will be positive between river miles 0 and 30 for 
 18

1 the period bracketing the tributary inputs of sand and future BHBF tests. If reaches 

2 downstream from river mile 30 are sand enriched relative to their condition before the 

3 2004 BHBF test, then sandbar building in these downstream reaches will be greater than 

4 was observed in these reaches during the 2004 BHBF test. 

5 

6 Methods 

7 

8 Hydrodynamic, sediment transport, grain size, temperature, conductivity, and turbidity 

9 data are to be collected at five locations (Lees Ferry gaging station, river mile 30, river 

10 mile 61, Grand Canyon gaging station, and above Diamond Creek gaging station) and on 

11 two Lagrangian river trips (tracking the water between river miles 0 and 226). 

12 Suspended-sediment data are collected using both conventional and laser-acoustic 

13 methodologies. Stage, discharge, and water-quality data are to be collected using standard 

14 USGS methodologies. Similar work conducted during the 1996 and 2004 BHBF tests and 

15 2000 low summer steady flow experiment is described in Konieczki and others (1997), 

16 Rubin and others (1998, 2002), Topping and others (1999, 2000a, 2000b, 2006a, 2006b), 

17 Rubin and Topping (2001), and Hazel and others (2006). Analyses (as described in Rubin 

18 and others, 1998, and Topping and others, 1999, 2006b) of sediment-transport and sand 

19 grain-size data, and analyses of reach-based sand budgets will be used to evaluate the 

20 results of future BHBF tests relative to the BHBF tests conducted in 1996 and 2004. If 

21 the working hypotheses are supported by these analyses, then rebuilding and maintenance 

22 of sandbars might be possible through use of repeated future BHBFs conducted under 

23 sand-enriched conditions. If the working hypotheses are rejected by these analyses, then 

24 flow and non-flow strategies in addition to or other than BHBFs may be needed to restore 

25 and maintain sandbars in the Colorado River ecosystem (further constraint of operations, 

26 sediment augmentation, or a combination of both). 

27 

28 Links/Relationship to Other Projects 29 

30 This project builds on the large quantity of previous published work on sediment 

31 transport, erosion, and deposition in the Colorado River ecosystem downstream from 

32 Glen Canyon Dam. It is also linked to several BHBF-related physical, sociocultural, and 

33 biological projects, including experimental studies 1.B (Studies of eddy-sandbar 

34 hydrodynamics, sediment transport, and bathymetry during future BHBF tests), 1.C 

35 (Response of sandbars and selected cultural sites to BHBF tests conducted under 

36 sediment-enriched conditions), 2 (Evaluate effect of future BHBF tests on riparian plant 

37 community development at multiple surface elevations and depositional environments), 

38 and 3 (future BHBF test effects on lower trophic levels in the CRE). Work conducted 

39 under this project will also be used by the ongoing project of the USGS’s Lew Coggins, 

40 Scott Wright, and Nick Voichick relating fish-catch rates to suspended-sediment 

41 concentration and grain size. 

42 

43 Information Needs Addressed 44 

45 The project will directly address multiple information needs, for example, as follows: 

46 
 19

1 EIN 8.1.1 How do fine sediment abundance, grain-size, and distribution in the 

2 main channel below 5,000 cfs change in response to an experiment performed 

3 under the Record of Decision, unanticipated event, or other management action? 

4 

5 EIN 8.3.1 How does fine sediment abundance, grain-size, and distribution, within 

6 eddies below 5,000 cfs change in response to an experiment performed under the 

7 Record of Decision, unanticipated event, or other management action? 

8 

9 EIN 8.4.1 How does fine sediment abundance, grain-size, and distribution, within 

10 eddies between 5,000 to 25,000 cfs change in response to an experiment 

11 performed under the Record of Decision, unanticipated event, or other 

12 management action? 

13 

14 RIN 8.5.1 What elements of Record of Decision operations (upramp, downramp, 

15 maximum and minimum flow, MLFF, HMF, and BHBF) are most/least critical to 

16 conserving new fine-sediment inputs, and stabilizing sediment deposits above the 

17 25,000 cfs stage? 

18 

19 RIN 8.5.2 What is the reach-scale variability of fine-sediment storage throughout 

20 the main channel? 

21 

22 RIN 8.1.3, RIN 8.2.1, RIN 8.3.1, RIN 8.5.6 What fine sediment abundance and 

23 distribution, by reach, is desirable to support GCDAMP ecosystem goals? [Note: 

24 Definition of “desirable” will be derived from targets for other resources and 

25 managers goals.] 

26 

27 RIN 7.3.1 Develop simulation models for Lake Powell and the Colorado River to 

28 predict water quality conditions under various operating scenarios, supplant 

29 monitoring efforts, and elucidate understanding of the effects of dam operations, 

30 climate, and basin hydrology on Colorado River water quality.

31 

32 Products/Reports 33 

34 Several peer-reviewed journal article(s) and/or USGS report(s) will be produced based on 

35 the findings of one or more future BHBF studies within 12–18 months of the BHBF 

36 testing. 

37 
 20

1 Costs by Fiscal Year (specific fiscal years shown here are for cost estimating 

2 purposes only) 

3 

 FUNDING HISTORY Fiscal year 

 2006 2007 2008 2009 2010 2011 

Outside GCMRC 

Science/Labor $118,200 $26,000 

Logistics Field Support $110,000 -0- 

Project Related 

Travel/Training $7,000 $5,000 

Operations/Supplies $12,000 $15,000 

GCMRC Salaries $30,000 $30,000 

Project Subtotal $277,200 $76,000 

GCMRC overhead $35,300 $14,500 

Project Total $312,500 $90,500 

% Total Outsourced 43% 34% 

4 
 21

1 Experimental Study 1.B: Studies of eddy-sandbar hydrodynamics, 

2 sediment transport, and bathymetry during BHBF tests 

3 

4 

5 Duration 

6 

7 20 months 

8 

9 Principal Investigator(s)

10 

11 Scott Wright, USGS-WRD California Water Science Center; Mark Schmeeckle, Arizona 

12 State University; and Matt Kaplinski, Northern Arizona University 

13 

14 Geographic Scope 

15 

16 Middle Marble Canyon around Eminence (river mile 45) 

17 

18 Project Goal(s) 

19 

20 The goal of this project is to improve our understanding of the time evolution of eddy 

21 sandbars during future BHBF tests. Knowledge of the rate of deposition or erosion of 

22 eddy sandbars during future BHBF tests will assist in the determination of the optimal 

23 BHBF hydrograph shape for a given sand-supply condition to achieve sandbar resource 

24 management goals, while minimizing negative impacts to other resources (e.g., 

25 hydropower). 

26 

27 Need for Project 

28 

29 The development of predictive capabilities for the evolution of eddy sandbars, a primary 

30 recommendation of the August 2006 sediment protocol evaluation panel (Wohl and 

31 others 2006), has been limited by a lack of information on hydrodynamics, sediment 

32 transport, and bathymetry during future BHBF tests. The lack of predictive capability has 

33 in turn limited our ability to provide definitive recommendations related to experimental 

34 BHBF peak discharge and duration. The existing eddy model (Wiele and others, 1996; 

35 Wiele, 1998) has been tested only with before and after bathymetry downstream from the 

36 Little Colorado River following floods in 1993. Also, initial investigations of eddy 

37 hydrodynamics and sediment transport during the November 2004 BHBF test indicate 

38 that some of the assumptions in the existing model are not supported by the data (Wright 

39 and Gartner, 2006). Thus, detailed data are needed on eddy hydrodynamics and 

40 morphology during future BHBF tests, if we are to improve our predictive capabilities 

41 and thus improve our ability to identify future BHBF characteristics that most effectively 

42 rebuild and maintain available sand resources and related habitats. 

43 
 22

1 Strategic Science Question(s) 

2 

3 4.1-1 Is there a “Flow-Only” operation (i.e. a strategy for dam releases, 

4 including managing tributary inputs with BHBFs, without sediment 

5 augmentation) that will restore and maintain sandbar habitats over decadal time 

6 scales? 

7 

8 4.1-1a What are the short-term responses of sandbars to BHBFs? 

9 

10 4.1-1b What is the rate of change in eddy storage (erosion) during time intervals 

11 between BHBFs? 

12 

13 4.1-1c What are the effects of ramping rates on sediment transport and sandbar 

14 stability? 

15 

16 Working Hypotheses 

17 

18 Sand deposition rates in eddies during future BHBF tests are regulated by (1) the 

19 interaction of the flow field with the antecedent bed topography and (2) the upstream 

20 sand supply. At a given location for a given BHBF hydrograph, an eddy sandbar will 

21 grow over time if the upstream sand supply is sufficiently large; conversely, if the 

22 upstream sand supply is insufficient, an eddy sandbar will erode over time. 

23 

24 Methods 25 

26 This project collects hydrodynamic, sediment transport, bathymetric, and load-cell data at 

27 several eddy sandbars in middle Marble Canyon in order to improve our understanding of 

28 eddy-sandbar hydrodynamics and evolution during future BHBF tests. 

29 

30 We will use two separate methods to collect information on (1) the detailed temporal 

31 evolution of eddy sandbars at a sparse spatial resolution, and (2) the detailed spatial 

32 structure of hydrodynamics, sediment transport, and bathymetry at a sparse temporal 

33 scale. Ideally, sites throughout Marble and Grand Canyons would be studied during a 

34 single BHBF, but this is not logistically feasible. As a compromise, sites in middle 

35 Marble Canyon will be studied because (1) results from the November 2004 BHBF test 

36 indicate that eddies in this reach may provide varied responses, and (2) there are several 

37 eddy sandbars close to each other that have been studied previously as part of the 

38 Northern Arizona University long-term sandbar monitoring and the Integrated Fine39 Sediment Team (FIST) projects. 

40 

41 The detailed temporal evolution of eddy sandbars at a sparse spatial resolution will be 

42 measured by deploying an array of load sensors in three eddy sandbars in the reach 

43 around river mile 45 (Eminence). The load sensors proposed for use here were used 

44 successfully for this purpose in Grand Canyon during the 1996 BHBF test (Carpenter, 

45 1996) and for monitoring the infilling of spawning gravels with fine sediment (see 

46 http://www.rickly.com/ss/scoursensor.htm for a product description). The study team 

47 proposes to bury 3–4 load sensors within each eddy sandbar at different elevations to 
 23

1 capture deposition or erosion that occurs during the rising limb, peak, and falling limb of 

2 the experimental BHBF hydrograph. 

3 

4 The detailed spatial structure of hydrodynamics, sediment transport, and bathymetry at a 

5 sparse temporal scale will be measured with a sonar system and an acoustic doppler 

6 current profiler (ADCP) using automated shore-based boat position tracking. The study 

7 area is within a FIST project reach, so the survey control is already established. The team 

8 will map the eddy sandbars where the load sensors are deployed as frequently as possible 

9 under the logistical constraints. At minimum, we plan to obtain a map of each eddy 

10 sandbar before future BHBF tests, during the rising limb, on the peak, during the falling 

11 limb, and after future BHBF tests. The ability to get multiple maps during a given 

12 segment will depend on the timing of experimental BHBFs (i.e., mapping will only be 

13 possible during daylight hours) and the peak duration. Each survey will result in a 

14 bathymetric map of the eddy sandbar and a map of the time-averaged 3-dimensional 

15 velocity structure of the eddy. Additionally, the team will collect sediment samples and 

16 attempt to calibrate the acoustic backscatter from the ADCP to suspended-sand 

17 concentration (we have had success with this in the past; see Topping and others, 2006). 

18 If successful, we will further develop maps of time-averaged suspended-sand 

19 concentration within each eddy for each survey, which, when combined with the velocity 

20 maps, will allow us to generate maps of the time-averaged flux of suspended-sand within 

21 the eddy. 

22 

23 Links/Relationship to Other Projects 24 

25 This project is linked closely to previous and ongoing work related to numerical 

26 modeling eddy-sandbar morphology. The data acquired through this initiative has the 

27 potential to significantly enhance ongoing and potential future developments of 

28 numerical models of eddy-sandbar responses to high-flow releases from the dam. The 

29 project is also linked to several other experimental BHBF-related physical, sociocultural, 

30 and biological projects by providing sediment transport data, eddy-sandbar bathymetry, 

31 and eddy-sandbar hydrodynamics and morphology, including experimental studies 1.A 

32 (Reach-scale changes in the fine-sediment mass balance and grain size during future 

33 BHBF tests), 1.C (Response of sandbars and selected culture sites to BHBF tests 

34 conducted under sediment-enriched conditions), 2 (Evaluate effect of future BHBF tests 

35 on riparian plant community development at multiple surface elevations and depositional 

36 environments), and 3 (BHBF testing effects on lower trophic levels in the CRE). 

37 

38 Information Needs Addressed 39 

40 The project will directly address several experimental and research information needs, as 

41 follows: 

42 

43 EIN 8.3.1 How does fine sediment abundance, grain-size, and distribution, 

44 within eddies below 5,000 cfs change in response to an experiment performed 

45 under the Record of Decision, unanticipated event, or other management action? 

46 
 24

1 EIN 8.4.1 How does fine sediment abundance, grain-size, and distribution, 

2 within eddies between 5,000 to 25,000 cfs change in response to an experiment 

3 performed under the Record of Decision, unanticipated event, or other 

4 management action? 

5 

6 RIN 8.5.1 What elements of Record of Decision operations (upramp, downramp, 

7 maximum and minimum flow, MLFF, HMF, and BHBF) are most/least critical to 

8 conserving new fine-sediment inputs, and stabilizing sediment deposits above the 

9 25,000 cfs stage? 

10 

11 RIN 7.3.1 Develop simulation models for Lake Powell and the Colorado River to 

12 predict water quality conditions under various operating scenarios, supplant 

13 monitoring efforts, and elucidate understanding of the effects of dam operations, 

14 climate, and basin hydrology on Colorado River water quality.

15 

16 Products/Reports 17 

18 One or more peer-reviewed journal article(s) or USGS report(s) will be produced based 

19 on the findings of this study. 

20 

21 Costs by Fiscal Year (specific fiscal years shown here are for cost estimating 

22 purposes only) 

23 

FUNDING HISTORY FY 2007 FY 2008 

Outside GCMRC Science/Labor $52,820 $74,779 

Logistics Field Support & MPS $17,000 

Project Related Travel/Training $1,000 $2,000 

Operations/Supplies $11,000 $2,000 

GCMRC Salaries 

Project Subtotal $81,820 $78,779 

DOI Customer Burden (6–17%) $7,183 $1,430 

Project Total $89,003 $80,209 

% Total Outsourced 65% 95% 

24 

25 

26 
 25

1 Experimental Study 1.C: Response of sandbars and selected 

2 cultural sites to Future BHBF 

3 Tests conducted under sediment-enriched conditions 

4 

5 

6 Duration 

7 

8 20 months 

9 

10 Principal Investigator(s) 

11 

12 David Rubin and Amy Draut, USGS GD-Western Coastal and Marine Geology; Rod 

13 Parnell, Matt Kaplinski, and Joe Hazel, Northern Arizona University; David Topping, 

14 USGS WRD-National Research Program; and Jack Schmidt, Utah State University 

15 

16 Geographic Scope 

17 

18 Numerous fan-eddy complexes, with associated campsites, and select cultural sites 

19 between river miles 0 and 226 

20 

21 Project Goal(s) 

22 

23 The goals of this project are to determine: (1) whether future BHBF tests conducted 

24 under sediment-enriched conditions can be used to maintain/sustain eddy sandbars and 

25 associated campsites in the Colorado River ecosystem, and (2) whether sediment 

26 deposited in arroyo mouths and/or increased aeolian flux of sand from the larger eddy 

27 sandbars produced during sand-enriched BHBF tests can offset ongoing erosion of 

28 archeological sites, thereby contributing to their preservation potential. 

29 

30 Need for Project 

31 

32 This project is required to document whether future BHBF tests conducted under 

33 sediment-enriched conditions can be used to maintain/sustain eddy sandbars and 

34 associated campsites and archaeological sites in the Colorado River ecosystem (Topping 

35 and others, 2006). Furthermore, this project will address whether such BHBFs can be 

36 used to hinder arroyo development or expansion in areas that contain cultural resources. 

37 BHBFs can result in partial to full infilling of arroyos either directly (by deposition of 

38 sand in arroyos during BHBFs) or indirectly (by increases in sandbar area leading to 

39 increased aeolian sand transport upslope into areas containing cultural sites). In addition, 

40 previous work has shown that the grain size of eddy-sandbar surfaces is the most 

41 important regulator of sand transport in the Colorado River over multiyear timescales 

42 (Topping and others, 2005) and that the coarsening of the channel bed and sandbar 

43 surfaces reduces the subsequent export of sand from the system. Data will be collected as 

44 part of this project to further advance our understanding of these effects. The 

45 documentation of effects of flow management options on aeolian sand transport provides 
 26

1 necessary follow-up data to the observed effects of the 2004 BHBF test (Draut and 

2 Rubin, 2006) and also complements ongoing investigations by researchers from Utah 

3 State University on processes that affect gully incision in sediment deposits in the river 

4 corridor. 

5 

6 Strategic Science Question(s) 

7 

8 4.1 Is there a “Flow-Only” operation (i.e. a strategy for dam releases, including 

9 managing tributary inputs with BHBFs, without sediment augmentation) that will 

10 restore and maintain sandbar habitats over decadal time scales? 

11 

12 4.1a What are the short-term responses of sandbars to BHBFs? 

13 

14 4.1b What is the rate of change in eddy storage (erosion) during time intervals 

15 between BHBFs? 

16 

17 2.1 Do dam controlled flows increase or decrease rates of erosion at 

18 archeological sites and TCP sites, and if so, how? 

19 

20 2.3 If flows contribute to archeological site/TCP erosion, what are the optimal 

21 flows for minimizing impacts to these cultural resources? 

22 

23 3.9 How do varying flows positively or negatively affect campsite attributes that 

24 are important to visitor experience? 

25 

26 Working Hypotheses 

27 

28 Future BHBF tests conducted under magnitudes and longitudinal distributions of sand 

29 enrichment similar to those before the 2004 BHBF test will result in sandbar building and 

30 low-elevation gully infilling comparable to that observed during the 2004 BHBF test. If 

31 reaches downstream from river mile 30 are sand enriched relative to their condition 

32 before the 2004 BHBF test, then sandbar building and gully infilling in these downstream 

33 reaches will be greater than was observed in these reaches during the 2004 BHBF test. 

34 Additional hypotheses specific to the role of experimentally BHBF-enriched sandbars in 

35 increasing aeolian flux of sand to downwind archeological sites, thereby increasing their 

36 preservation potential, include: 

37 1. More wind-blown sand will be transported into modern fluvial sourced (MFS) 

38 aeolian deposits during the spring windy season immediately following a sandbar39 building flood experiment than in the spring windy season preceding the 

40 experiment. As defined by Draut and Rubin (2007), MFS deposits are those 

41 immediately downwind of fluvial sandbars that lie below the 45,000 cfs stage. 

42 This hypothesis is based on observations at 24.5 mile following the 2004 BHBF 

43 test (Draut and Rubin, 2006). 

44 2. If dam releases that follow a winter to early spring BHBF test are managed 

45 with subsequent dam releases such that greater dry sandbar area is available in the 
 27

1 spring windy season, compared to the spring 2005 windy season, then presumably 

2 aeolian sand transport rates into MFS deposits may be higher than those observed 

3 in spring 2005, given comparable wind conditions. This hypothesis is qualified by 

4 the caveat that the shape of a sandbar (not just its area) relative to the shoreline 

5 and the moisture content of a sandbar are important in determining aeolian sand 

6 transport inland. 

7 3. Future BHBF tests on the order of 45,000 cfs will not result in significantly 

8 increased aeolian sand transport into relict fluvial sourced (RFS) aeolian deposits 

9 as defined by Draut and Rubin (2007; RFS deposits formed as the wind reworked 

10 sediment from extensive predam flood deposits essentially in place, and do not 

11 necessarily lie downwind of <45,000 cfs-stage fluvial sandbars). This hypothesis 

12 is based on measurements made within RFS dune fields at Palisades (river mile 

13 66) and Comanche (river mile 68) following the 2004 BHBF test. 

14 

15 Methods 

16 

17 This project will collect and analyze topographic, bathymetric, sedimentologic (grain 

18 size), campable area, meteorological, geomorphic, and aeolian sand-transport data at fan19 eddy complexes and selected cultural sites. Geomorphic mapping, scour chain 

20 installation, and associated interpretive work will be conducted using established 

21 methods by scientists from Utah State University (Schmidt and others, 1999). 

22 Topographic and multibeam bathymetric surveys will be collected before and after future 

23 BHBF tests using established methods by scientists from Northern Arizona University 

24 (Hazel and others, 1999; Kaplinski and others, 2005). These data will be collected at 

25 numerous fan-eddy complexes located throughout Marble and Grand Canyons and at 

26 selected cultural sites. Analog cameras will be used at 28 selected sandbars and cultural 

27 sites to document the topographic evolution (by fluvial and aeolian processes) of these 

28 sites during and after future BHBF tests. River-based arroyos associated with selected 

29 cultural sites will also be surveyed as part of this study (See table 1.C-1 for locations of 

30 various project components.) 

31 

32 Grain size on the riverbed and on sandbar surfaces will be studied using an underwater 

33 microscope (Chezar and Rubin, 2004; Rubin and others, 2006) and digital image 

34 processing (Rubin, 2004). Grain size in flood deposits on sandbars will be measured 

35 using by sampling vertical profiles (Rubin and others, 1998) and standard lab analyses. 

36 Sedimentary structures in flood deposits will be examined by installation and excavation 

37 of scour chains, by trenching, and by inspection of natural cut banks. 

38 

39 Weather instrument stations will measure wind, rainfall, and aeolian sand transport at the 

40 targeted cultural sites listed above. These instruments will be deployed during February 

41 2007, with the exception of the Malgosa site (river mile 57.9), where equipment would be 

42 deployed before future BHBF testing occurs. This part of this project will build on the 

43 findings of Draut and Rubin’s 2003–06 study on the role of aeolian sediment in the 

44 preservation of cultural sites (Draut and others, 2005; Draut and Rubin, 2005, 2006, 

45 2007), specifically the finding from the 2004 BHBF test that high-flow releases in the 
 28

1 CRE can increase wind-blown transport of sand toward some of the aeolian deposits that 

2 contain archeological material, increasing their preservation potential. 

3 

4 Table 1.C-1. Locations of various project components. (* Individual study sites are 

5 associated with one or more archaeological sites. All river miles are generalized to 

6 protect the confidentiality of archaeological site locations.) 

7 

Day 

on 

river 

trip 

Sandbar 

topography, 

Campsite area, 

Scour chains 

Bathymetry, 

Underwater 

microscope 

Aeolian 

sandtransport 

work* 

Arroyo 

surveys* 

Cameras 

 0 -9 Mile 

 1 3L, 8L, 16L 3L, 16L 2.6R, 8.2R 

 2 22R, 24L, 29L, 

30R 

22R, 30R 24 16.7R,22.0L, 

24.5L 

 3 32R, 33L, 35L 32R, 35L 30.8L 

 4 41R, 43L, 44L 41R, 43L, 

44L 

 41.3L,44.5R 

 5 45L, 47R, 50R, 

51L 

45L, 47R, 

51L 

 47.6R, 50.1L 

 6 55R, 56R, 62R 55R, 62R 58, 60 55.9L, ~58L 

 7 65R, 68R 65R, 68R 66, 69 66L, 66R 

 8 69R,72R 69L, 72L 

 9 81L, 84R, 87L, 

88R 

 81.7R,87.6R 

10 119R, 122R, 

123R 

122R 104.4L, 19.3L, 

123.2R 

11 137L, 139R, 

145L 

139R 135 137.7R, 145.8R 

12 172L, 183R 172L 172.6R, 183.3L 

13 194L, 202R 194L 194.6L, 202.3L 

14 213L, 220R, 

225R 

225R 203, 223 213.3R, 225.5L 

15 39 sandbars 22 eddies 29 camera sites 

8 

9 

10 Analyses (similar to those described in Rubin and others, 1998; Hazel and others, 1999, 

11 2006; Schmidt and others, 1999; Topping and others, 1999, 2006a; and Draut and Rubin, 

12 2005, 2006, 2007) of sandbar topographic response, sandbar stratigraphy, sand grain-size 

13 data, aeolian sand-transport data, and aeolian topographic response at cultural sites will 

14 be used to evaluate the results of future BHBF tests relative to the BHBF tests conducted 

15 in 1996 and 2004. If the working hypotheses are supported by these analyses, then 

16 restoration and maintenance of sandbars might be possible through use of BHBFs 

17 conducted under sand-enriched conditions. Furthermore, if the working hypothesis 

18 specific to the aeolian sand-transport study are supported by these analyses, preservation 

19 of archeological sites might be increased by the greater aeolian flux of sand to these sites 

20 from the larger dry upwind sandbars produced during experimental BHBFs. If the 

21 working hypotheses are rejected by these analyses, then additional flow and non-flow 

22 treatments (such as further constraints on dam operations, sediment augmentation or a 

23 combination of both) in association with future BHBF tests may be needed to restore and 

24 maintain sandbars throughout the Colorado River ecosystem. 
 29

1 Links/Relationships to Other Projects 2 

3 This project builds on the large quantity of previous published work on sediment erosion 

4 and deposition in the Colorado River ecosystem downstream from Glen Canyon Dam. It 

5 is also linked to several other experimental BHBF-related physical, sociocultural, and 

6 biological projects, including experimental studies1.A (Reach-scale changes in the fine7 sediment mass balance and grain size during future BHBF tests), 1.B (Studies of eddy8 sandbar hydrodynamics, sediment transport, and bathymetry during future BHBF tests), 2 

9 (Evaluate effect of BHBF tests on riparian plant community development at multiple 

10 surface elevations and depositional environments), and 3 (future BHBF testing effects on 

11 lower trophic levels in the CRE). Bed sediment grain-size data collected as part of this 

12 task will be used to help interpret shifts through time in the sediment rating-curve data 

13 collected as part of experimental studies 1.A and 1.B and predicted by many modeling 

14 studies. Similarly, grain-size grading of flood deposits will be compared to temporal 

15 changes in suspended-sediment grain size observed during high flows (components of 

16 experimental studies 1.A and 1.B). 

17 

18 The subsequent evolution of the post-BHBF backwaters surveyed as part of this project 

19 will be evaluated in the subsequent fall during the backwater seining trip. Extension of 

20 the aeolian/archaeological site study supplements ongoing weather monitoring, aeolian 

21 transport, and gully-erosion monitoring work. It also extends the applications of the Draut 

22 and others (2005, 2006) study on the role of aeolian sediment in the preservation of 

23 archaeological sites that collected similar data from 2003 to 2006, and therefore will 

24 provide valuable comparison data between the 2004 and future BHBF experiments. In 

25 addition, this study complements ongoing investigations by Joel Pederson and Gary 

26 O’Brian from Utah State University on geomorphic processes that affect gully incision in 

27 Colorado River sediment deposits. 

28 

29 Information Needs Addressed 30 

31 The project will directly address multiple effects information needs and research 

32 information needs, as follows: 

33 

34 EIN 8.3.1 How does fine sediment abundance, grain-size, and distribution, within 

35 eddies below 5,000 cfs change in response to an experiment performed under the 

36 Record of Decision, unanticipated event, or other management action? 

37 

38 EIN 8.4.1 How does fine sediment abundance, grain-size, and distribution, within 

39 eddies between 5,000 to 25,000 cfs change in response to an experiment 

40 performed under the Record of Decision, unanticipated event, or other 

41 management action? 

42 

43 RIN 8.5.4 What is the significance of aeolian processes in terrestrial sandbar 

44 reworking? 

45 
 30

1 EIN 8.5.1 How does fine sediment abundance, grain-size, and distribution on 

2 shorelines between 25,000 cfs and the uppermost effects of maximum dam 

3 releases change in response to an experiment performed under the Record of 

4 Decision, unanticipated event, or other management action? 

5 

6 EIN 9.3.1 How do the size, quality, and distribution of camping beaches change 

7 in response to an experiment performed under the Record of Decision, 

8 unanticipated event, or other management action? 

9 

10 RIN 11.1.1a What and where are the geomorphic processes that link loss of site 

11 integrity with dam operations as opposed to dam existence or natural processes? 

12 

13 RIN 11.1.5 What are appropriate strategies to preserve resource integrity? 

14 

15 EIN 11.1.1 Determine the effects of experimental flows on historic properties. 

16 

17 Products/Reports 18 

19 Several peer-reviewed journal article(s) and/or USGS report(s) will be produced based on 

20 the findings of this study within 12–18 months of future BHBF tests. 

21 

22 Costs by Fiscal Year (specific fiscal years shown here are for cost estimating 

23 purposes only) 

24 

 Funding history Fiscal year 

 2006 2007 2008 2009 2010 2011 

Outside GCMRC 

Science/Labor $310,100 $119,900 

Logistics Field 

Support $120,000 -0- 

Project Related 

Travel/Training $3,000 $3,000 

Operations/Supplies $19,500 $5,000 

GCMRC Salaries 

Project Subtotal $452,600 $127,900 

GCMRC overhead $40,600 $6,800 

Project Total $493,200 $134,700 

% Total Outsourced 69% 94% 

25 

26 

27 
 31

1 Experimental Study 2: Evaluate effect of Future BHBF Tests on 

2 riparian plant community development at multiple surface 

3 elevations and depositional environments: Are open patches more 

4 susceptible to exotic species colonization and establishment than 

5 sites with existing vegetation following a disturbance? 

6 

7 Duration 

8 

9 18 months 

10 

11 Principal Investigator(s) 

12 

13 Barbara Ralston, U.S. Geological Survey, Grand Canyon Monitoring and Research 

14 Center 

15 

16 Geographic Scope 

17 

18 Glen Canyon Dam to lower Marble Canyon (river mile 61) 

19 

20 Project Goal(s) 

21 

22 The project goals are to document community compositional changes (native vs. 

23 nonnative species) in established and newly bare depositional environments across 

24 multiple surface elevations following a future BHBF test. The project goal addresses a 

25 subcomponent of a larger question posed in the Knowledge Assessment (Melis and others 

26 2006): To what extent and in what respects can BHBF tests (magnitude and frequency) 

27 achieve reduction of exotic species? 

28 

29 Need for Project 

30 

31 Riparian areas are a highly susceptible to exotic species introductions and expansion 

32 (Graf, 1978; Thébaud and Debussche, 1991; Naiman and others, 2005). Furthermore, the 

33 successful establishment of an invasive species may be affected by the degree to which a 

34 community is developed at a site. Two competing hypotheses exist regarding site 

35 susceptibility to invasive species. Darwin (1859), Elton (1958), Moulton and Pimm, 

36 (1983), Case (1990), and Case and Bolger (1991) suggest that invasion success decreases 

37 as community size and structural complexity increase. Stohlgren and others (1998, 1999) 

38 postulate the opposite hypothesis, arguing that species-rich sites, such as riparian zones, 

39 are more susceptible to exotic species introductions than upland areas that may have 

40 lower species richness. The latter argues for temporarily increased resource availability 

41 associated with disturbance, while the former argues that fewer exploitable habitats are 

42 available, thus preventing new species introductions (MacArthur and Wilson, 1967; 

43 Pimm, 1991). 
 32

1 In human-impacted systems, determining the relationship between native and nonnative 

2 species richness and site susceptibility is important for long-term resource management. 

3 A high-flow event provides a unique opportunity to compare riparian vegetation 

4 community composition (i.e., native/nonnative ratios) in established vegetation sites 

5 subject to disturbance with large bare sites made available from sediment reworking 

6 during a future BHBF test. By comparing established and new bare sites at multiple 

7 surface elevations, scientists should be able to identify the sites that are most susceptible 

8 to nonnative species introductions and expansion. Identification of susceptible sites 

9 provides managers the opportunity to focus resources when considering nonnative 

10 species control measures following a large disturbance event. 11 

12 Strategic Science Question(s) 

13 

14 4.1. Is there a flow-only operation (i.e., strategy for dam releases, including 

15 managing tributary inputs with BHBFs without sediment augmentation) that will 

16 rebuild and maintain sandbar habitats over decadal time scales? 

17 

18 Working Hypotheses 

19 

20 Hypothesis 1: Native/nonnative species richness ratios are the same across all habitats 

and surface elevations up to 1,699 m3 21 /s. 

22 

23 Alternative hypothesis: The ratio between native/nonnative richness and cover at sites 

24 with established vegetative communities will not change following disturbance because 

25 resource availability is limited by the presence of existing species. Bare areas will have 

26 ratios of native/nonnative richness and cover values similar to those of established sites. 

27 Surface elevation will not have an affect on native/nonnative richness and cover values. 

28 

29 Alternative hypothesis: The ratio between native/nonnative richness and cover at sites 

30 with established vegetative communities will shift toward an increase in nonnative 

31 richness and cover because of the increased nutrient availability associated with the 

32 experimental BHBF disturbance. Native/nonnative richness and cover ratios will change 

33 by surface elevation with nonnative species decreasing with increasing surface elevations 

34 in relation to available soil nutrients. Bare areas will favor nonnative species across all 

35 surface elevations. 

36 

37 Methods 

38 

39 Plots established by Kearsley (2006) as a part of riparian vegetation monitoring will be 

40 used to assess native/nonnative foliar cover. These plots occur at specific river miles 

41 (table 2.1) and include data collected from 2001 to 2005. Reassessment of these locations 

42 provides an opportunity to examine native/nonnative cover and richness ratios across 

43 years and relative to a large scale disturbance within a year. These plots are also linked to 

the following surface elevations: 226, 424, 708, 991, 1,274, and 1,699 m3 44 /s. At each 

location, surveys of foliar cover of all species found with four 1m2 45 plots located at each 

46 surface elevation will be recorded. Many of these sites occur in channel margin locations 
 33

1 and will likely experience some disturbance but would be unlikely to be completely bare 

2 following a future BHBF test. 

3 

4 Percent foliar cover will be determined by using 10 cm grids on 1m frames. Field readers 

5 will count the number of cross-sectional grid points that coincide with the presence of a 

6 given species. This is more accurate than field crews estimating percent cover visually. 

7 All species encountered in a plot will be recorded and those species that have <1% cover 

8 will be identified as a trace and assigned a value of 0.01. All sites will be visited before a 

9 future BHBF test as a part of monitoring. Sampling following a future BHBF test will 

10 take place in association with post-flood sandbar monitoring trips, which will occur in 

11 mid-summer at the height of plant productivity and in the fall in association with regular 

12 monitoring. 

13 

14 Bare ground sites: Similarly sized plots will be established in newly identified 

15 depositional environments (e.g., sandbars, return current channels). Surface elevations 

16 will be determined for these sites and data collection will follow that of the established 

17 vegetation sites. 

18 

19 Soil collection: To determine how soil constituents and grain size affect species 

20 composition, soil samples will be collected at each site and analyzed for available 

21 nitrogen, total carbon, and particle size. Four soil samples will be taken at each site and at 

each surface elevation. One sample will be taken from the mid point of each 1m2 22 plot. 

23 The sample will be external of the plots so as not to disturb the plots. Standing litter will 

24 be removed before sampling and sample depths will be at least 15 cm. A soil sampler will 

25 be used to collect the soil cores. Samples will be combined into a single soil sample for 

26 each surface elevation per site. Analysis will be conducted by an external lab to be 

27 determined. Samples will be collected before and after a future BHBF test at the 

28 established vegetation plots to determine if soil constituents and grain sized changed as a 

29 result of an experimental BHBF. 

30 

31 Analysis: Species cover data from each surface elevation will be pooled to determine 

32 total cover and richness, as well as richness and cover values for native and nonnative 

33 species. Native/nonnative values will be compared using analysis of variance (ANOVA). 

34 Established and bare ground sites will be compared using multiple regressions. Stepwise 

35 regression will be used with soil data to determine the effect of soil constituents and 

36 particle size on native/nonnative cover and richness values. 

37 
 34

1 Table 2.1. Established vegetation by river mile (R=river right and L=river left) 

2 

Establish vegetation sites 

by river mile 

 -6.0R 

 -2.0L 

 00.2R 

 02.7L 

007.3L 

008.1L 

012.3R 

018.2L 

020.8R 

035.1L 

037.7R 

040.8R 

041.2R 

042.6L 

043.9L 

047.0L 

053.2R 

056.1R 

059.6L 

3 

4 Links/Relationships to Other Projects 

5 

6 This project augments general riparian vegetation monitoring because it incorporates 

7 exiting monitoring locations into data collection efforts. By using surface elevations as 

8 site location criteria, the project also links species richness and cover to operational 

9 effects on riparian vegetation across surface elevations. In terms of integrating research 

10 across resources, this project will produce data that supports experimental study 1.C 

11 (Response of sandbars and selected culture sites to future BHBF tests conducted under 

12 sediment-enriched conditions) by sampling reworked and bare sandbars and return 

13 current channel substrates, collecting and analyzing soil samples for grain-size 

14 information, and identifying plant species components in marsh and riparian habitats. It 

15 also will helps to answer a cultural research information need 11.2.3 (Determine 

16 acceptable methods to preserve or treat traditionally important resources within the 

17 Colorado River ecosystem) by providing data relevant for improving our understanding 

18 of how BHBF testing may affect culturally important native plant species composition 

19 and distributions relative to invasive nonnative species. 

20 
 35

1 Information Needs Addressed 

2 

3 This project directly addresses and experimental information need for M.O. 6.5 

4 associated with riparian vegetation. 

5 

6 EIN 6.5.1 How does the abundance and distribution of nonnative species change 

7 in response to an experiment performed under the Record of Decision, 

8 unanticipated event, or other management action? 

9 

10 Costs by Fiscal Year (specific fiscal years shown here are for cost estimating 

11 purposes only) 

12 

Activity FY 2007 FY 2008 

Outside GCMRC 

Science/Labor $15,800 (1⁄2 time NAU technician) $16,000 

Logistics Field Support 

and NPS 

Collections combined with fish, 

sediment and vegetation mapping 

trips if possible None in 2008 

Project Related 

Travel/publication costs $3,000 $3,000 

Operations/Supplies $9,100 

Soil sampler $100.00 

Soil analysis: 480 samples (6 

samples/site X 40 sites X 2 

sampling events) @~18.00/sample $500.00 

GCMRC Salaries 

Project Subtotal $27,900 $21,700 

 DOI Customer Burden 

(6–17%) $2,686 $2,720 

Project Total $30,586 $24,420 

% Total Outsourced 

13 
 36

1 Experimental Study 3: BHBF Testing effects on lower trophic 

2 levels in the Colorado River Ecosystem 

3 

4 

5 Duration 

6 

7 19 months 

8 

9 Principal Investigators

10 

11 Theodore Kennedy, USGS Grand Canyon Monitoring and Research Center; Wyatt Cross 

12 and Robert Hall, University of Wyoming; and Emma Rosi-Marshall, Loyola University, 

13 Chicago 

14 

15 Geographic Scope 

16 

17 Glen Canyon, the confluence of the Little Colorado River, and Diamond Creek (river 

18 miles -15 to 226) 

19 

20 Project Goal(s) 

21 

22 To measure how future BHBF testing affects the quantity, quality, and types of food 

23 available for invertebrates, and ultimately fish. 

24 

25 Need for Project 

26 

27 Previous food base research has demonstrated that a BHBF test causes short-term 

28 reductions in primary producer and invertebrate biomass (Blinn and others, 1999; 

29 McKinney and others, 1999). Blinn and others (1999) and McKinney and others (1999) 

30 focused on static measures (i.e., algal biomass, invertebrate biomass) at a relatively 

31 coarse temporal scale (i.e., monthly measurements following the flood). Although 

32 biomass of algae and invertebrates will be temporarily reduced following a BHBF test, it 

33 is possible the post-BHBF algal assemblage will be faster growing and of higher quality, 

34 leading to higher invertebrate growth rates (Note: production=biomass*growth). Higher 

35 invertebrate growth rates post-BHBF could compensate for short-term reductions in 

36 invertebrate biomass. That is, short-term (i.e., weeks) negative effects of a future BHBF 

37 test on biomass may be offset by longer term (i.e., months-year) increases in invertebrate 

38 growth rates, which would result in more food available to higher trophic levels. 

39 

40 Future BHBF tests are likely to alter the systemwide carbon budget that we are currently 

41 constructing. Consequently, we will quantify fluxes of transported organic matter before, 

42 during, and after future BHBF experiments. Although these types of measurements have 

43 been taken during previous BHBF tests, none of the data have been linked to whole44 system carbon budgets. This information will be critical for ultimately measuring the 

45 effect of future BHBF tests on inputs, retention, and export of organic matter that fuels 

46 river food webs. 

47 
 37

1 There is evidence that disturbances, such as those that might occur during future BHBF 

2 tests, lead to an algal assemblage that is dominated by fast-growing and nutritious taxa. 

3 Brock and others (1999) measured production of algae covered rocks in Glen Canyon 

4 before and after the 1996 BHBF test. They demonstrated that, although algal biomass on 

5 rocks was lower following the BHBF test, rates of net primary production and production 

6 to respiration ratios were both higher after the BHBF test. They attributed these changes 

7 to the removal of detritus and senescent algal biomass. Because rapidly growing and 

8 young algae are more nutritious than senescent algae or detritus, the study by Brock and 

9 others (1999) suggests that the post-BHBF algal assemblage was of higher quality for 

10 invertebrates than the pre-BHBF algal community. Numerous studies in Sycamore Creek, 

11 a desert stream in southern Arizona, have demonstrated that following a scouring flood 

12 the algal assemblage shifts towards more nutritious and faster growing taxa (i.e., 

13 diatoms), invertebrates readily consume these new food resources, and that invertebrate 

14 biomass rapidly recovers to pre-flood levels (Fisher and others, 1982; Grimm and Fisher, 

15 1989; Peterson and others, 1994). 

16 

17 Working Hypotheses 

18 

19 Hypothesis 1: A short-duration BHBF test in late winter scours the benthos, 

20 causing short-term reductions in algal and invertebrate biomass, and results in an 

21 overall decrease in annual invertebrate production (see figure 3.1). 

22 

23 Hypothesis 2: A short-duration BHBF test in late winter scours the benthos, 

24 causing reductions in algal biomass, but the new successional community of 

25 primary producers is of higher quality, more productive, and is assimilated more 

26 efficiently by invertebrates, leading to no change in annual invertebrate production. 

27 

28 Hypothesis 3: A short-duration BHBF test in late winter initially scours the 

29 benthos, causing reductions in algal biomass, but the new successional assemblage 

30 of primary producers is of higher quality, more productive, and is assimilated more 

31 efficiently by invertebrate consumers, thereby increasing annual invertebrate 

32 production (see figure 3.1). 

33 

34 Our research will test these competing hypotheses of recovery following a BHBF test. 

35 Direct measurements of invertebrate and fish growth before and after BHBF testing is 

36 intractable. However, we may be able to infer how invertebrate or fish growth rates 

37 are affected by future BHBF tests by measuring indices of growth (ribosomal RNA; 

38 Elser and others, 2003) and by quantifying invertebrate and fish diets and using 

39 literature values to determine the assimilation efficiencies of principle food resources. 

40 We will also measure whether a BHBF test changes the quality (i.e., C:N, C:P) of 

41 algal assemblages. Collectively, the proposed research will measure how a BHBF test 

42 affects the quantity and quality of food available for fishes and whether indicators of 

43 rainbow trout growth are affected by changes in food resources. 

44 

45 
 38

1 Figure 3.1. Potential effects of a BHBF test on invertebrate production

2 

3 

4 

5 

6 Tasks: 

7 • Measure how a BHBF test alters the carbon budget for the CRE. 

8 o Measure the composition, biomass, and nutrient content of basal resources 

9 (algae, submerged aquatic vegetation, benthic organic matter) 

10 o Quantify whole system metabolism, a measure of primary production and 

11 resource consumption 

12 o Prior to BHBF, quantify standing mass of leaf litter between 20-41k cfs 

13 stage elevation 

14 o Measure organic drift during BHBF 

15 • Measure how a BHBF test affects invertebrate biomass and production 

16 o Quantify invertebrate composition, abundance, and biomass 

17 o Quantify invertebrate diets and growth indicators (i.e., ribosomal RNA) 

18 • Measure impact of a BHBF test on growth and condition indices (i.e., ribosomal 

19 RNA) for rainbow trout in Lees Ferry (in collaboration with Korman and others) 

20 

21 We will compare the above measures before and after a future BHBF test, and again in 

22 the following year at the same time when no BHBF test occurs. Frequent measurements 

23 before and after a BHBF test (i.e., -7d, -1d, +1d, +3d, +7d, +14d), coupled with ongoing 

24 quarterly sampling at the Little Colorado River confluence and monthly sampling at Glen 

25 Canyon and Diamond Creek, will allow us to measure the short- and long-term effects of 

26 a BHBF test on food quantity and quality. 

27 

Time

Flood 

Invertebrate 

Production 

(mg/m2

/d) 

Hypothesis 1 

Hypothesis 3 

Potential Effects of a BHBF on Invertebrate Production 
 39

1 Methods 

2 

3 We will measure biomass of lower trophic levels (i.e., algal and invertebrate biomass, 

4 cover and canopy height of submerged aquatic vegetation, organic drift) coupled with 

5 dynamic process oriented measures (i.e., nutrient content of basal resources, ribosomal 

6 RNA of invertebrates and fish, open-channel metabolism measurements) to test how a 

7 BHBF experimental release affects annual invertebrate production. Methods described 

8 briefly below are presented in more detail in our original food base proposal (Hall and 

9 others, 2005). 

10 

11 We will sample algae, submerged aquatic vegetation, and benthic organic matter with 

12 appropriate area-specific sampling devices (e.g., Ponar and Hess samplers, rock scrapes, 

13 modified suction sampler); dried to a constant mass, weighed, ashed in a muffle furnace 

14 (at 450 deg C); and reweighed to determine total dry mass and organic mass. Dried 

15 samples of these food base components will also be analyzed for carbon, nitrogen, and 

16 phosphorus content following standard methodology (CHN analyzer, acid digestion and 

17 spectrophotometry, APHA 1998). Open-channel metabolism in the Glen Canyon reach 

18 will be quantified before and after the BHBF with continuously deployed Yellow Springs 

19 Instruments (YSI) data sondes (with optical probes) using a two-station diel oxygen 

20 change method, corrected for re-aeration (e.g., Hall and Tank, 2003; see Hall and others, 

21 2005). Downstream in Grand Canyon, we will measure metabolism using a one-station 

22 technique as part of the food base project (Hall and others, unpublished). Metabolism will 

23 be measured continuously at Diamond Creek for a period of a week before, and several 

24 months after, a BHBF test. At the Little Colorado River, metabolism will be measured 

25 continuously for one week before, and two weeks after, a future BHBF test. Coarse and 

26 fine organic drift will quantified using depth-integrated Miller net and grab samples 

27 respectively before, during, and after a future BHBF test at each site. Invertebrates will 

28 be quantified on multiple substrate types (i.e., cliff faces, talus slopes, cobble bars, 

29 depositional areas) with appropriate area-specific sampling devices (e.g., modified 

30 suction sampler, rock grabs, Hess sampler, ponar dredge). Dietary analysis will be 

31 conducted on invertebrates before and on multiple occasions after (days 1, 3, 7, 14, 30) a 

32 BHBF test using digital imaging software (Image Pro 3.0). Dominant dietary items can 

33 be easily identified with this method (e.g., diatoms, amorphous detritus, leaves, animal 

34 prey; Benke and Wallace, 1980; Hall and others, 2000). Ribosomal RNA analysis will be 

35 conducted on dominant invertebrates and fishes as a proxy for growth rate and condition 

36 (see Elser and others, 2003). 

37 

38 Links/Relationships to Other Projects 

39 

40 This project is linked to experimental Study 1.B (Studies of eddy-sandbar 

41 hydrodynamics, sediment transport, and bathymetry during future BHBF tests). We will 

42 share transported sediment samples and analyze them for both sediment and organic 

43 matter and determine what affect a BHBF test has on organic matter transport. 

44 
 40

1 Experimental effects information needs (EIN) addressed by the proposed research 

2 include: 

3 EIN 1.1.1 How does primary productivity for the reach between Glen Canyon 

4 Dam and the Paria River change in response to an experiment performed under 

5 the Record of Decision, unanticipated event, or other management action? 

6 

7 EIN 1.2.1 How do benthic invertebrates in the reach between Glen Canyon Dam 

8 and the Paria River change in response to an experiment performed under the 

9 Record of Decision, unanticipated event, or other management action? 

10 

11 EIN 1.3.1 How does primary productivity in the Colorado River ecosystem 

12 below the Paria River change in response to an experiment performed under the 

13 Record of Decision, unanticipated event, or other management action? 

14 EIN 1.4.1 How do benthic invertebrates in the Colorado River ecosystem below 

15 the Paria River change in response to an experiment performed under the Record 

16 of Decision, unanticipated event, or other management action? 

17 

18 EIN 1.5.1 How does drift in the Colorado River ecosystem change in response to 

19 an experiment performed under the Record of Decision, unanticipated event, or 

20 other management action? 

21 

22 Costs by Fiscal Year (specific fiscal years shown here are for cost estimating 

23 purposes only) 

24 

25 

 FUNDING Fiscal year 

2007 2008 

Coop Agreement—Outside GCMRC Science/Labor & Travel 

Principal Investigators $21,000 

Coop Agreement—Outside GCMRC Science/Labor-Technicians $45,000 

Logistics Field Support & NPS $23,800 

Project related travel $2,000 

Operations/Supplies $13,500 

Equipment $25,000 

Publication charges $5,000 

GCMRC Salaries& benefits 

Project Subtotal $132,300 $5,000 

 DOI Customer Burden (6-17%) $16,683 $955 

Project Total $148,983 $5,955 

% Total Outsourced 

26 
 41

1 Experimental Study 4.A: Effects of Future BHBF Tests on rainbow 

2 trout early life stage survival, and the distribution, mortality, and 

3 potential downstream movement of age-1 fish in the Lees Ferry 

4 reach

5 

6 

7 Duration 

8 

9 10 months 

10 

11 Principal Investigator(s) 

12 

13 J. Korman, Ecometric, Inc. (GCMRC cooperator) 

14 

15 Geographic Scope 

16 

17 Glen Canyon Dam to Lees Ferry (river miles -15 to 0) 

18 

19 Project Goal(s) 

20 

21 This project seeks to determine how BHBF tests affect spawning, survival of early life 

22 history stages of rainbow trout in the Lees Ferry reach, and potential for simulating 

23 downstream migration of age-1 fish. Hypotheses that will be evaluated are: (1) a future 

24 BHBF test will scour redds (spawning nests) but the effect on the juvenile population will 

25 be limited because of compensatory survival responses, and (2) a BHBF test will alter the 

26 distribution of age-1 fish in the Lees Ferry reach resulting in either higher mortality or 

27 migration out of the reach. 

28 

29 Need for Project 

30 

31 The size of the adult population of rainbow trout in the Lees Ferry reach is very likely 

32 regulated by the survival rate and dynamics of early life stages (Houde, 1987). This 

33 experimental BHBF project would increase our understanding of these dynamics and 

34 therefore contribute to better management of the Lees Ferry trout fishery. Trout from 

35 Lees Ferry may migrate downstream and have negative effects on native fish (Korman 

36 and others, 2005; L. Coggins, unpublished data). The extent of downstream migration 

37 may be density dependent (Clone and Anderson, 1992), a normal ontogenetic habitat shift 

38 (Elliott, 1986), and/or stimulated by high flows (Heggenes and Traaen, 1988; Jensen and 

39 Johnsen, 1999; Mitro and others, 2003). A better understanding of the dynamics of the 

40 Lees Ferry population and the effects of a BHBF test therefore has implications for the 

41 control of trout densities downstream. 

42 
 42

1 Strategic Science Question(s) 

2 

3 • To what extent could predation impacts by nonnative fish be mitigated by higher 

4 turbidities or dam controlled high-flow releases? 

5 • To what extent is the adult population of rainbow trout controlled by survival 

6 rates during incubation and age-0/juvenile rearing stages, or by changes in growth 

7 and maturation in the adult population influencing egg deposition? 

8 • Do rainbow trout immigrate from Glen to Marble and eastern Grand Canyons, 

9 and if so, during what life stages? 

10 

11 Working Hypotheses 

12 

13 To evaluate these hypotheses we will compare: (1) the number of redds before and after 

14 the high-flow event to compute the potential loss of redds because of high flows; (2) the 

15 ratio of the density of newly emerged fry to the total number of redds constructed with 

16 ratios determined in 2003, 2004, and 2006 (Korman and others, 2005); and (3) compare 

17 the abundance and distribution of age-1 fish before and after the BHBF test. We predict 

18 that: (1) redd numbers will be reduced by a future BHBF test because of scour; (2) the 

19 ratio of fry to redds will be similar to other years (2006=Record of Decision flows, 

20 2003/4=experimental flows) because of strong compensatory mechanisms that occur 

21 shortly after emergence (Elliott, 1994); and (3) distribution of age-1 fish in Lees Ferry 

22 fish will be different after the BHBF because there will be a reduction in abundance 

23 because of mortality or downstream movement (Korman and others 2005; L. Coggins, 

24 GCMRC, unpublished data). It may be possible to determine whether mortality or 

25 movement was the cause for change in abundance, if age-1 fish are tagged as part of the 

26 proposed GCMRC sonic telemetry program. 

27 

28 Methods 

29 

30 The existing 2007 budget for the Rainbow Trout Early Life Stage Survival (RTELSS) 

31 project supports five redd surveys and one age-0 survey, a substantial reduction in effort 

32 from previous years because of funding constraints (Korman and others, 2005). The 

33 proposed BHBF test component would require: (1) five additional redd surveys to 

34 provide a more accurate and detailed estimate of redd numbers and timing of spawning; 

35 (2) three additional juvenile fish surveys to compute the age-0 to redd ratio (July sample) 

36 and to describe the change in abundance and distribution of age-1 fish (before and after 

37 BHBF sample); (3) support for physical modeling to develop a depth and velocity map 

38 for a range of discharges for the entire Lees Ferry reach. The currently supported juvenile 

39 fish survey is scheduled to occur in the late fall and provides an annual index of age-0 

40 abundance (altering the timing of this survey disrupts the time series). 

41 

42 With regards to item (3) above, as fish grow they use deeper and faster habitats (Gaudin, 

43 2001). Current age-0 surveys have been restricted to generally quite slow water (but 

44 sometimes deep) that is broadly distributed along the shoreline in the Lees Ferry reach. 

45 However, larger age-0 fish and age-1 fish appear to concentrate in the limited number of 

46 shorelines with faster water where food availability is higher (Korman and Yard, 
 43

1 unpublished data). We need to sample these habitat types in order to provide a 

2 representative description of how high flows change abundance and distribution. The 

3 physical model would allow us to design a representative sampling regime for age-1 fish 

4 and scale-up density samples to estimate age-1 population size before and after a BHBF. 

5 Predictions of depth and velocity in Lees Ferry reach would also be useful for assessing 

6 redd scour, which we will evaluate in the field by before-after mapping of redds as part of 

7 our regular survey, and burial of existing spawning areas with sand (as apparently 

8 occurred at 6 and 8 mile sandbars as a result of the 1996 BHBF test). Data collected from 

9 past RTELSS efforts, and a complete topographical map of the Lees Ferry reach 

10 developed by the GCMRC would be integrated in an existing 2D hydrodynamic 

11 modeling framework developed by the USGS. 

12 

13 Links/Relationships to Other Projects 

14 

15 It is important to determine the how food-web dynamics influence the density and growth 

16 of rainbow trout in the Lees Ferry reach. Downstream migration of trout from the Lees 

17 Ferry reach resulting from a BHBF test will be studied by the GCMRC. Trout captured as 

18 part of the proposed study could be used as part of GCMRC’s downstream movement 

19 assessment and the data would be very useful for interpreting downstream 

20 movement/mortality. 

21 

22 Information Needs Addressed 

23 

24 RIN 4.2.7 What dam release patterns most effectively maintain the Lees Ferry 

25 rainbow trout trophy fishery while limiting rainbow trout survival below the Paria 

26 River? 

27 
 44

1 Costs by Fiscal Year (specific fiscal years shown here are for cost estimating 

2 purposes only) 

3 

4 

 2007 

Outside GCMRC 

science/labor $35,000 

Logistics field support 

and NPS 

5 redd survey trips, 3 electrofishing 

trips, all in Lees Ferry reach 

$2,000 

Project related 

travel/publication costs $3,000 

Operations/supplies 

GCMRC salaries 

Project Subtotal $40,000 

 DOI customer burden 

(6–17%) $2,132 

Project total $42,132 

% Total outsourced 83% 

5 
 45

1 Experimental Study 4.B: Evaluate effects of a Future BHBF Test on 

2 adult trout distribution in Glen and Marble Canyons 

3 

4 

5 Duration

6 

7 19 months 

8 

9 Principal Investigator(s) 

10 

11 Daniel C. Gwinn, U.S. Geological Survey, Grand Canyon Monitoring and Research 

12 Center 

13 

14 Geographic Scope 

15 

16 Glen and Marble Canyons (river miles -15 to 61) 

17 

18 Project Goal(s) 

19 

20 The goals of this experimental study are: (1) to determine if a BHBF test causes 

21 displacement of rainbow trout from the Lees Ferry reach into Marble Canyon and eastern 

22 Grand Canyon; (2) to determine if such displacement is experienced differentially among 

23 different length fish; and (3) to provide a platform for Grand Canyon scientists to develop 

24 skills with acoustic technologies that can be applied to answering questions about native 

25 and nonnative fish movement and distribution and sampling efficiencies. 

26 

27 Need for Project 

28 

29 Native fishes of the Colorado River evolved in a system with an extremely flashy 

30 hydrograph with base flows as low as 5000 cfs and floods as great as 300,000 cfs. 

31 Although a BHBF of ~40,000 cfs would likely not disadvantage these native species, it is 

32 commonly observed in other systems that a naturally flashy hydrograph can disadvantage 

33 nonnative species (Meffe, 1984). It is currently unclear whether a moderate high-flow 

34 event of ~40,000 cfs could affect the nonnative fish community of the Colorado River 

35 and provide a management tool. During the BHBF test of 1996, Valdez and Cowdell 

36 (1996) observed an increase in catch rates of rainbow trout <152 mm total length in the 

37 Little Colorado River inflow reach of the Colorado River. They hypothesized that the 

38 presence of fish from Lees Ferry and Glen Canyon that were displaced into Grand 

39 Canyon by the BHBF test were likely responsible for these increased catch rates. They 

40 did not, however, observe any changes in the catch rates of other species of the nonnative 

41 fish community. After the 2004 BHBF test, Korman (pers. com.) observed a decrease in 

42 the catch rates of juvenile trout in Lees Ferry, which supports the Valdez and Cowdell 

43 (1996) hypothesis of displacement in 1996, but again direct observation of the fate of fish 

44 could not be made. Currently, we do not know if short duration BHBF testing displaces 

45 young trout from Lees Ferry and cannot infer this from experiments using abundance 

46 indices alone. This experimental study would employ the additional technology of 

47 acoustic telemetry to make direct observations of movement patterns of young rainbow 
 46

1 trout during a future BHBF test. This information in combination with relative-abundance 

2 measures will allow for stronger inference to be drawn about the fate of rainbow trout 

3 during a future BHBF test. This experimental study also provides an opportunity for 

4 scientists to gain the skills and experience with acoustic technologies that may prove 

5 important for addressing broader questions about Lees Ferry trout dispersal, movement 

6 dynamics, and sampling efficiency of other native and nonnative fish species in the 

7 Grand Canyon ecosystem. 

8 

9 Strategic Science Question(s) 

10 

11 1.3 Do rainbow trout immigrate from Glen to Marble and eastern Grand 

12 Canyons, and, if so, during what life stages? To what extent do Glen Canyon 

13 immigrants support the population in Marble and eastern Grand Canyons?

14 

15 1.4 Can long-term decreases in the abundance of rainbow trout in Marble and 

16 eastern Grand canyons be sustained with a reduced level of effort of mechanical 

17 removal or will recolonization from tributaries and from downstream and 

18 upstream of the removal reach require that mechanical removal be an ongoing 

19 management action?

20 

21 3.2 To what extent could predation impacts by nonnative fish be mitigated by 

22 higher turbidity or dam-controlled high-flow releases? 

23 

24 3.6 What Glen Canyon Dam operations (ramping rates, daily flow range, etc.) 

25 maximize trout fishing opportunities and catchability? 

26 

27 Working Hypotheses 

28 

29 Future BHBF tests will result in displacement young rainbow trout from the Lees Ferry 

30 reach into Marble Canyon and eastern Grand Canyon. This trout redistribution will be 

31 inversely related to the size of fish.

32 
 47

1 Methods 

2 

3 This experimental study will utilize abundance indices and sonic technologies to evaluate 

4 the possible age-specific displacement of adult rainbow trout from the Lees Ferry reach 

5 during a future BHBF test. Abundance indices will be established for adult and juvenile 

6 rainbow trout before and after the high-flow event for comparison. Prior to the BHBF, the 

7 GCMRC will execute a trout sampling trip following the protocol developed by the 

8 Arizona Game and Fish Department (AZGFD) for long-term monitoring of adult trout in 

9 Lees Ferry (Speas and others, 2002). The post-BHBF testing evaluation of adult trout 

10 abundance will include the use of AZGFD catch-rate information from the reoccurring 

11 long-term rainbow trout monitoring in the Lees Ferry reach. Additional electrofishing 

12 catch-rate information collected by Ecometric, Inc. (experimental study 4.A) will be used 

13 for abundance comparisons of pre- and post-BHBF testing juvenile trout abundance. In 

14 combination, these catch data will be used to infer changes in the abundance of adult and 

15 juvenile rainbow trout because of a future BHBF test. 

16 

17 Relative-abundance indices will be combined with direct observations of location and 

18 movement from acoustic telemetry to draw inference about the effects of a future BHBF 

19 test on the Lees Ferry trout population. The Colorado River upstream of Lees Ferry will 

20 be divided into three strata: upper (river mile -15 to -10), middle (river mile -10 to -5), 

21 and lower (river mile -5 to 0). Ten fish of age 1, 2, and 3 will be collected from each 

22 strata and tagged via intraperitoneal implantation for a total sample size of 90 implanted 

23 individuals. The minimum size fish implanted with a transmitter will be 108mm total 

24 length. With the appropriate acoustic transmitter, this represents a tag to fish body weight 

25 ratio of 12%, which has been demonstrated to have little to no affect on swim 

26 performance of juvenile hatchery-reared rainbow trout (Brown and others, 1999). Tagged 

27 fish will be held in net pens for 24 hours to allow recovery from surgeries. Recovery of 

28 all fish will be evaluated and individuals recovering poorly will be removed from the 

29 experiment. Fish will be released in their river stratum of origin. Released fish will be 

30 manually tracked daily for 1week to evaluate movement patterns and longer term 

31 response to surgeries. We expect to observe a dispersal pattern after release that stabilizes 

32 over the period of tracking. Movement downstream of Lees Ferry will be detected with 

33 five acoustic receiver gates. These will be deployed at Lees Ferry, route 89 bridge, 

34 Badger Creek, river mile 30, and river mile 60. Fish in the Lees Ferry reach will then be 

35 tracked for an additional 3days to assure data accuracy of the stationary receiver gates. A 

36 post-BHBF test electrofishing sampling protocol will be employed 1 week after the 

37 BHBF test to detect changes in the relative abundance of trout in the Lees Ferry trout 

38 fishery. 

39 

40 Links/Relationships to Other Projects

41 

42 This experimental study has direct linkage to experimental study 4.A, the long-term Lees 

43 Ferry trout monitoring effort, the FY07 sonic tag/gear efficiency evaluation, the FY07 

44 warmwater nonnative fish research, and future native fish research. Experimental studies 

45 4.A and 4.B are interrelated because of data and logistics sharing. Conducting these 

46 studies in concert will strengthen the inferences drawn from each about the fate of age-1 

47 trout in the Lees Ferry reach as relates to a BHBF test. This study also relies on Lees 
 48

1 Ferry long-term trout monitoring data collected by the AZGFD on relative abundance of 

2 adult trout in the Lees Ferry reach after a future BHBF test. Additionally, this study 

3 provides a platform for Grand Canyon scientists to gain valuable experience using sonic 

4 technologies to address a broader set of biological question. The experience gained from 

5 a future BHBF study will be employed in ongoing investigations of gear efficiencies and 

6 warmwater nonnative fish. These tools are also expected to be invaluable for future 

7 investigations of native fish in the Grand Canyon ecosystem. 

8 

9 Information Needs Addressed 

10 

11 The experimental study will directly address the following research information needs 

12 (RIN): 

13 

14 RIN 4.2.1 What is the rate of emigration of rainbow trout from the Lees Ferry 

15 reach? 

16 

17 RIN 4.2.2 What is the most effective method to detect emigration of rainbow 

18 trout from the Lees Ferry reach? 

19 

20 RIN 4.2.3 How is the rate of emigration of rainbow trout from the Lees Ferry 

21 reach to below the Paria River affected by abundance, hydrology, temperature, 

22 and other ecosystem processes? 

23 

24 Products/Reports

25 

26 A peer-reviewed journal article and/or USGS report will be produced based on the 

27 findings of this study. 

28 

29 Costs by Fiscal Year (specific fiscal years shown here are for cost estimating 

30 purposes only) 

31 

 FUNDING HISTORY Fiscal year 

 2006 2007 2008 2009 2010 2011 

Outside GCMRC 

Science/Labor 

$10,000 

 

Logistics Field 

Support & MPS 

Project Related 

Travel/Training $1,000 

Operations/Supplies $41,850 $3,000 

GCMRC Salaries $4,560 

Project Subtotal $56,910 

 DOI Customer 

Burden (6–17%) 

$10,269 

 

Project Total $70,679 

% Total Outsourced 

32 

33 

34 
 49

1 Experimental Study 5: Evaluate Effects of a Future BHBF Test on 

2 Water Quality of Lake Powell and Glen Canyon Dam Releases 

3 

4 

5 Principal Investigator(s) 

6 

7 William S. Vernieu, U.S. Geological Survey, Grand Canyon Monitoring and Research 

8 Center 

9 

10 Geographic Scope 

11 

12 Lake Powell forebay to upstream limit of the hypolimnion (~Oak Canyon, 90 km above 

13 the dam), Glen Canyon Dam, and the tailwaters to Lees Ferry 

14 

15 Project Goal(s) 

16 

17 The goal of this experimental study is to determine how the addition of jet tube and full 

18 powerplant releases from the dam will alter water quality in the Glen Canyon Dam 

19 tailwaters and the hydrodynamics and stratification patterns in Lake Powell. This effort 

20 will entail installation of an additional water-quality multiparameter sonde (MPS) at the 

21 ring follower gates in the dam, the inlet port of the river outlet works, and may include 

22 another MPS located below Glen Canyon Dam at a point where full mixing of combined 

23 discharges is achieved. In addition to the regularly scheduled monthly profiling in the 

24 Glen Canyon Dam forebay, additional monitoring locations will be added to include the 

25 upstream extent of the hypolimnion, between 45 and 90 km above the dam. Additional 

26 surveys of these locations will take place immediately before and immediately after a 

27 future BHBF test. During a future BHBF test, additional chemical samples will be taken 

28 in the dam, at Lees Ferry, and at the river outlets works depth in the reservoir before and 

29 after BHBF testing. 

30 

31 Need for Project 

32 

33 Use of the river outlet works, 30 m below the penstocks, draws water from deeper layers 

34 of the reservoir than normal powerplant releases. This water is cooler, has higher 

35 concentrations of dissolved minerals and nutrients, and has lower concentrations of 

36 dissolved oxygen. 

37 

38 Given the most probable timing of late fall to early spring for a BHBF test, this study is 

39 likely to occur concurrently with an annual event in the reservoir that has been 

40 documented by the Lake Powell monitoring program. During this event, an upwelling of 

41 the hypolimnion of the reservoir, driven by winter underflow density currents, is 

42 observed at Glen Canyon Dam and influences powerplant releases in the early spring. 

43 During a future BHBF test, the operation of the river outlets works, combined with full 

44 powerplant releases, could evacuate large volumes of this hypolimnetic water, causing 

45 mixing to deeper layers of the reservoir and reduction of the volume of stagnant 

46 hypolimnion. For this reason, the BHBF test of 1996 significantly mixed and diminished 
 50

1 the stagnant water in the hypolimnion (Hueftle and Stevens, 2001). Development of 

2 stagnation of the hypolimnion can produce hypoxic (low oxygen) conditions in the 

3 reservoir, which may in turn be discharged below the dam into the tailwaters. 

4 

5 The 2004 BHBF test occurred in November when convective mixing and reduced 

6 reservoir elevations brought upper lake layers closer to the release structures. 

7 Consequently, net releases during the 2004 BHBF test were drawn primarily from the 

8 surface layers and had little effect on hypolimnetic waters. February/March timing for a 

9 future BHBF test is more likely to release colder, saline, and hypoxic water from the 

10 hypolimnion. 

11 

12 In summary, a future BHBF test has the potential to entrain deeper layers of the reservoir, 

13 which could cause enhanced mixing of those layers and reduced stagnation and hypoxia. 

14 Releases downstream may deliver more nutrients to the aquatic ecosystem and the river 

15 outlet works would re-aerate hypoxic releases. 

16 

17 

18 Methods 

19 

20 Existing methodologies associated with the Lake Powell water-quality core monitoring 

21 program will be utilized to accomplish the objectives. Additional multiparameter sondes 

22 will be calibrated and deployed according to past standards. Added chemical samples will 

23 be collected and processed with monitoring samples; profiles will be conduced using 

24 existing equipment and methods. 

25 

26 

27 Links/Relationships to Other Projects

28 

29 Use of the river outlet works is likely to increase the export of nutrients and ions during 

30 the experimental flows, and could alter hypolimnetic mixing patterns and result in the 

31 increased evacuation of hypolimnetic water. This could provide additional nutrients to the 

32 aquatic food base in Grand Canyon in the recovery period following the experiment 

33 (Parnell and others, 1999; Shannon and others, 2001; Stevens and others, 2001; Schmidt 

34 and others, 2001). 

35 

36 

37 Products/Reports 

38 

39 A post-experiment report will summarize findings of data collection efforts and a 

40 discussion of changes to the stratification and water quality in Lake Powell and changes 

41 to the water quality of the Glen Canyon Dam tailwaters as a result of the experimental 

42 action. 

43 
 51

1 Costs by Fiscal Year (specific fiscal years shown here are for cost estimating 

2 purposes only) 

3 

4 Estimated Costs: 

5 Field work: 2-6 additional person-days 

6 Equipment: possible rental of 1-2 YSI MPS sondes for 2-3 months 

7 Sample analyses: 6-10 additional sets of samples 

8 Analysis: 4-12 additional person-days 

9 Logistics: 1-2 field trips from Wahweap to Oak Canyon 

10 

Lake Powell BHBF Projected 

Budget Fiscal year 

 2007 range 2007 mean 2008 

Outside GCMRC Science/Labor 

(NPS help 5-10 days) $- $- $- 

Logistics Field Support & MPS 

(1–2 boat trips to Oak, 1-2 MPS 

for 3 months $951 $1,902 $1,427 

Project Related Travel/Training 

(1–3 days) $264 $640 $452 

Operations/Supplies (6-10 

additional samples) $- $- $- 

GCMRC Salaries (10 field/6 

report-20 person days with 20% 

OH $9,895 $12,369 $11,132 $6,185 

Project Subtotal $11,110 $14,911 $13,011 $6,185 

 DOI Customer Burden (6–17%) $667 $2,535 $1,601 

Project Total $11,777 $17,446 $14,612 

% Total Outsourced 

11 
 52

1 Logistics activities in support of experimental studies

2 

3 

4 Scheduling Considerations 

5 

6 Scheduling a BHBF test during the spring period poses several considerations to the 

7 GCMRC Logistics Program. The primary logistical constraints for scheduling a BHBF 

8 test in the spring are: (1) consideration of scheduling impacts to the existing monitoring 

9 program, (2) providing adequate lead time for preparation to provide for increased 

10 capacity for adequate logistical support to respond to the additional demands required to 

11 support BHBF research, and (3) provide adequate time to work with the National Park 

12 Service on permitting activities and public outreach to address safety concerns for 

13 backcountry and river users during periods of high flows. 

14 

15 This draft BHBF science plan requires launching nine motorized research trips (plus an 

16 additional press trip) and support of research projects in the Glen Canyon reach and 

17 upstream of Diamond Creek. Trips are initiated 5 weeks before the high flow peak and up 

18 to 8 weeks after the peak flow, encompassing a 3 month time period. During this period 

19 of time in the spring, there are typically three major projects scheduled to conduct field 

20 research; mainstem fish monitoring (2 trips), aquatic food base, and sediment-mass 

21 balance. The combination of BHBF testing trips and regularly scheduled monitoring trips 

22 places a heavy demand on logistical resources available to the GCMRC Logistics 

23 Program. The increased demand exceeds the current capacity of the GCMRC Logistics 

24 Program requiring additional procurement of equipment, upgrade of current capacities, 

25 and coordination of additional external resources. 

26 

27 Funding must be made available to the logistics program 6 weeks before the scheduled 

28 launch of the first BHBF trip to that resources are available to support the experimental 

29 BHBF trips while maintaining adequate support for our regularly scheduled monitoring 

30 trips. 

31 

32 Permitting 

33 

34 The final BHBF science plan will be submitted to the Grand Canyon National Park 

35 Research Permits Office for review as a project Research and Collecting Permit. 

36 Following approval of a BHBF Research and Collecting Permit, individual trip permit 

37 applications will be submitted for each of the nine trips proposed in this science plan. 

38 Requests for permit approval should occur no less than 6 weeks before to the first BHBF 

39 research trip launch date. 

40 
 53

1 Public Outreach 

2 

3 The GCMRC will collaborate with the National Park Service to establish a public 

4 outreach plan to inform the public and specifically recreational river and backcountry 

5 users as to safety concerns because of high flows. In collaboration with the National Park 

6 Service, a handout will be prepared informing the public on the purpose and effects of 

7 any future BHBF tests, including a hydrograph of the peak flows, which will be 

8 distributed to all river and backcountry users who may be affected. This plan has also 

9 includes a budget for an unscheduled press river trip. 

10 

11 Logistics 

12 

13 Any future BHBF tests will require nine motorized trips to support the proposed research 

14 activities outlined in this plan. Two trips will launch in advance of the BHBF test. Four 

15 trips will be launched before the BHBF test to be stationed at 30 mile, 45 mile, 60 mile 

16 and Phantom Ranch to conduct sampling pre-, post- and during the event. One trip 

17 launches on the initiation of the peak flow and the final two trips are conducted post18 BHBF test. Additionally, work will take place in the Glen Canyon reach between Lees 

19 Ferry and Glen Canyon Dam and upstream of Diamond Creek at river mile 225. 

20 

21 

 Project Boats Location Trip Length # Personnel 

Trip 1

 

4b 22’, 1-sport (Achilles) RM 0–225 12 days 6–8 

Trip 2 1c 2-33’,1-22’ (Eyeball), 1-

22’ (Hydro), 1-sport 

(Osprey) 

RM 0–225 18 days 18–20 

Trip 3 1a/3 1-33’, 2-sport (Osprey) RM 61 20 8–12 

Trip 4 1b 1-33’, 1-22’ (Hydro) RM 45 16 6–8 

Trip 5 1a/KAS 

compliance 

1-33’, 1-sport (Osprey) RM30 16 6–8 

Trip 6 1a 1-33’, 1-22’, 1-Sport 

(Achilles) 

RM 87/ Lower 

Langrangian 

14 6–8 

Trip 7 1a 1-33’, 1-22’ Upper 

Langrangian 

12 6–8 

Trip 8 1c 2-33’,1-22’ (Eyeball), 1-

22’ (Hydro), 1-sport 

(Osprey) 

RM 0–225 18 18–20 

Trip 9 1c 2-33’ RM 0–225 18 12–14 

22 

23 

24 Recommended Timeline

25 

26 • Final Approval BHBF Test and Hydrograph (date and hour specific) 

27 • Permitting and Logistical Planning Initiated (6 weeks) 

28 • First BHBF Research Trip Launches (5 weeks) 

29 • High Flows initiated (8 weeks) 

30 • Final Post-BHBF Test Trip Launches 

31 
 54

1 Estimated Logistics Costs (using FY 2007 costs) 

2 

Experimental studies and 

associated logistical support 

activities 

Projected cost Projected cost 

(included in study 

budgets) 

1a $110,000 

1b $20,000 

1c $120,000 

2 0 

3 $24,000 

4a $11,000 

4b $32,000 

 

Direct Logistics Costs: 

Equipment (inc. Truck) $25,000 

Salary (overtime) $8,000 

Survey Equipment $10,000 

Hydro Boat Modifications $5,000 

Public Outreach (press trip) $15,000 

Burden (19.091%) $14,890 

TOTAL $92,890 
 55

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2 

3 American Public Health Association, 1998, Standard methods for the examination of 

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6 

7 Andrews, E.D., Johnston, C.E., Schmidt, J.C., and Gonzales, M., 1999, Topographic 

8 evolution of sand bars, in Webb, R.H., Schmidt, J.C., Marzolf, G.R., and Valdez, R.A., 

9 eds., The controlled flood in Grand Canyon: Washington, D.C., American Geophysical 

10 Union, Geophysical Monograph Series, v. 110, p. 117–130. 

11 

12 Arreguin-Sanchez, F., 1996, Catchability: a key parameter for fish stock assessment: 

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14 

15 Benke, A. C., and Wallace, J. B., 1980, Trophic basis of production among net-spinning 

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17 

18 Blinn, D.W., Shannon, J.P., Wilson, K.P., O'Brien, C., and Benenati, P.L., 1999, 

19 Response of benthos and organic drift to a controlled flood, in Webb, R.H., Schmidt, 

20 J.C., Marzolf, G.R., and Valdez, R.A., eds., The controlled flood in Grand Canyon: 

21 Washington, D.C., American Geophysical Union, Geophysical Monograph Series, v. 

22 110, p. 259–272. 

23 

Booth, B.D., and Swanton, C.J. 2002. 50th 24 anniversary –Invited article: Assembly theory 

25 applied to weed communities. Weed Science 50:2–13. 

26 

27 Brock, J.T., Royer, T.V., Snyder, E.B., and Thomas, S.A, 1999, Periphyton metabolism: 

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29 eds., The controlled flood in Grand Canyon: Washington, D.C., American Geophysical 

30 Union, Geophysical Monograph Series, v. 110, p. 217–223. 

31 

32 Brown, R.S., Cooke, S.J., Anderson, W.G., and McKinley, R.S., 1999, Evidence to 

33 challenge the “2% Rule” for biotelemetry, North American Journal of Fisheries 

34 Management, v. 19, p. 867–871. 

35 

36 Carpenter, M.C., 1996, Monitoring erosion and deposition using an array of load-cell 

37 scour sensors during the spring 1996 controlled flood experiment on the Colorado 

38 River in the Grand Canyon, Arizona [abs.]: American Geophysical Union Transactions, 

39 v. 77, no. 46, p. F271. 

40 

41 Carpenter, S.R., and Kitchell, J.F., eds. 1996, The trophic cascade in lakes: Cambridge, 

42 England, Cambridge University Press, 385 p. 

43 

44 Case, T.J. 1990. Invasion resistance arises in strongly interacting species-rich model 

45 competition communities. Proceedings of the National Academy of Science 87:9610–

46 9614. 
 56

1 Case, T.J. and Bolger, D.T., 1991. The role of introduced species in shaping the 

2 distribution and abundance of island reptiles. Evolutionary Ecology 5:272–290. 

3 

4 Chezar, H., and Rubin, D., 2004, Underwater microscope system: U.S. Patent and 

5 Trademark Office, patent number 6,680,795, January 20, 2004, 9 pages. 

6 

7 Clarke, K.R., 1993, Non-parametric multivariate analyses of change in community 

8 structure: Australian Journal of Ecology, v. 18, p. 117–143. 

9 

10 Close, T.L, and Anderson, C.S., 1992. Dispersal, density-dependent growth, and survival 

11 of stocked steelhead fry in Lake Superior tributaries: North American Journal of 

12 Fisheries Management, v. 12, p. 728–735. 

13 

14 Coggins, L.G., Pine, W.E., III, Walters, C.J., Van Haverbeke, D.R., Ward, D., Johnstone, 

15 H.C., 2006, Abundance trends and status of the Little Colorado River population of 

16 humpback chub: North American Journal of Fisheries Management, v. 26, p. 233–245. 

17 

18 Coggins, L., Yard, M., Persons, B., Van Haverbeke, R., and David, J., 2005, Results of 

19 hoopnet sampling to examine changes in juvenile humpback chub abundance and size 

20 before and after the 2004 experimental high flow: Presentation to the Adaptive 

21 Management Workgroup, March 3, 2005, http://www.usbr.gov/uc/rm/amp/ 

22 amwg/mtgs/05mar02/documents/Attach_07h.pdf. 

23 

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26 Draut, A.E., and Rubin, D.M., 2005, Measurements of wind, aeolian sand transport, and 

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29 http://pubs.usgs.gov/of/2005/1309/ 

30 

31 Draut, A.E., Rubin, D.M., Dierker, J.L., Fairley, H.C., Griffiths, R.E., Hazel, J.E., Jr., 

32 Hunter, R.E., Kohl, K., Leap, L.M., Nials, F.L., Topping, D.J., and Yeatts, M, 2005, 

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35 Survey Scientific Investigations Report 2005-5072, 68 p., 

36 http://pubs.usgs.gov/sir/2005/5072/ 

37 

38 Draut, A.E., and Rubin, D.M., 2006, Measurements of wind, aeolian sand transport, and 

39 precipitation in the Colorado River corridor, Grand Canyon, Arizona—January 2005 to 

40 January 2006: U.S. Geological Survey Open-File Report 2006-1188, 88 p., 

41 http://pubs.usgs.gov/of/2006/1188/ 

42 

43 Draut, A.E., and Rubin, D.M., in press, The role of aeolian sediment in the preservation 

44 of archaeological sites in the Colorado River corridor, Grand Canyon, Arizona—Final 

45 report on research activities, 2003–2006: U.S. Geological Survey Open-File Report 

46 2007-1001 [RECEIVED DIRECTOR’S APPROVAL ON 1/3/07]. 
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10 
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1 Appendix A. Responses to Issues Raised by Members of the Glen 

2 Canyon Dam Adaptive Management Program about Future BHBF 

3 Tests 

4 

5 During their December 5–6, 2006 meeting, members of the Glen Canyon Dam 

6 Adaptive Management Program (GCDAMP) identified issues of concern for the Grand 

7 Canyon Monitoring and Research Center (GCMRC) to consider and address in planning 

8 for future BHBF tests. These concerns are summarized below from the meeting minutes 

9 and are followed by short responses prepared by GCMRC staff and cooperating 

10 scientists. 

11 Issue: What are the trade-offs between the benefits of a BHBF test and possible 

12 negative impacts? 

13 This is a broad question and one that GCMRC staff worked to address with input 

14 from the entire science staff. Please see table A-1 for a summary of the pros and cons 

15 associated with BHBF testing in spring. 

16 Issue: If a proposed future test is a new (BHBF) test, then what are the new 

17 hypotheses? 

18 The proposal for a future spring high-flow experiment is a hybrid of the two 

19 previous experiments that have been conducted and one that tries to incorporate key 

20 learning from 1996 and 2004. The next proposed high-flow experiment intends to return 

21 to the original timing of spring for such a flow operation as described in the 1995 

22 Operation of Glen Canyon Dam Final Environmental Impact Statement (EIS), a timing 

23 that attempts to approximate the spring flood disturbance regime of the ecosystem that 

24 typically occurred before the construction of Glen Canyon Dam. It is also a second test of 

25 the concept of implementing high-flow experiments within a period when new sand 

26 supplies are known to exist in the main channel following tributary sand inputs. The 2004 

27 BHBF test revealed that fall sand inputs from the Paria River were retained in the upper 

28 reaches of Marble Canyon under constrained daily dam operations that varied between 

29 5,000 and 10,000 cubic feet per second (cfs). As a result, sediment experts determined 

30 that the resulting sandbar building using the sand supply was restricted to the upper half 

31 of Marble Canyon and that the new sand did not have time under that 60-hour test to be 

32 transported to reaches downstream of about river mile 40 or so. 

33 Analysis of the 2004 results yielded a revised hypothesis regarding sand transport. 

34 This new hypothesis postulated that new sand inputs that enter the ecosystem from the 

35 Paria River should be allowed some limited time to be transported downstream under 

36 Record of Decision fluctuations into lower Marble Canyon. Hence, there is an evolving 

37 question about the appropriate timing for when high-flow experiments should optimally 

38 be tested and implemented relative to: (1) the seasonal timing of when tributary sand 

39 typically is introduced to the ecosystem from the Paria River (late summer to fall), (2) 

40 how the new sand gets distributed downstream through Marble and Grand Canyons under 

41 Record of Decision operations within the months following inputs, (3) whether 
 66

1 redistributing the new sand in a more uniform longitudinal pattern downstream before a 

2 high-flow experiment results in more uniform and robust sandbar deposition, and (4) the 

3 season in which historical flood disturbance occurs (spring). 

4 Proposed future BHBF tests are intended to have additional studies tied to food 

5 base, fisheries, and cultural site preservation; the hypotheses associated with these studies 

6 are described in the experimental study descriptions included in this science plan. 

7 Issue: What is the reason behind replicating the 2004 (BHBF test) hydrograph? 

8 The concept of replicating the 2004 BHBF test hydrograph was discussed 

9 extensively among cooperating sediment scientists at the 2005 knowledge assessment 

10 workshop convened by the GCMRC with stakeholders. The 2004 test hydrograph was 

11 designed on the basis of sandbar simulations for a subset of eddies under a scenario of 

12 45,000 cfs peak magnitude and sand concentrations that were measured in the postdam 

13 era. This, along with data collected from the 1996 BHBF test, was the basis for choosing 

14 60 hours, down from 168 hours tested in 1996, as the duration for the peak flow of a 

15 future BHBF tests. The 2004 BHBF test peak magnitude was limited to 41,500 cfs, 

16 owing because one of the eight turbine units at Glen Canyon Dam was undergoing 

17 maintenance. The concept of replication of the 2004 BHBF test hydrograph in a future 

18 test is aimed at determining whether or not the robust sandbar-building responses that 

19 occurred under the 2004 BHBF test will occur consistently each time a BHBF test is 

20 released under sand-enriched conditions. It also allows scientists to evaluate whether 

21 there are incremental cumulative benefits to sandbar conservation in lower Marble 

22 Canyon and Grand Canyon reaches each time enriched high-flow experiments occur. 

23 If the results from replicating the 2004 BHBF test hydrograph under sand24 enriched conditions in the spring (following several months of downstream transport 

25 under Record of Decision operations) are as good or better (more uniformly distributed 

26 sandbar responses under conditions of more uniformly distributed sand supply 

27 downstream) than those measured during the 2004 BHBF test, then this approach may be 

28 interpreted at being a sustainable strategy for longer term habitat restoration and 

29 maintenance using only downstream sand supplies. Such a replicated, positive result 

30 would also indicate that the more natural timing for flood disturbance in spring can be 

31 accomplished as well, while conserving new sand inputs before they are exported to the 

32 upper Lake Mead delta. On the other hand, if a different BHBF test hydrograph is 

33 released and the results are not as good as 2004 BHBF test results, then the lack of 

34 replication will make it very difficult to determine whether the response owed to the 

35 different BHBF test timing and supply conditions or to the different hydrograph. 

36 Because the 2004 BHBF test hydrograph design was tied to sandbar and eddy 

37 simulations made on the basis of measured channel topography and sediment transport 

38 data, and because the 2004 test did result in robust sandbar building in the reach (upper 

39 Marble Canyon) where the sand supply was locally enriched, it seems reasonable to 

40 return to this hydrograph design for future BHBF testing to confirm its effectiveness. 

41 
 67

1 Issue: What would the pros and cons of a shorter-duration BHBF test peak at 

2 41,500 cfs (for instance, 30 hours)? 

3 Discussions among scientists and managers about alternative duration (shorter 

4 than the 60-hour peak tested in 2004 BHBF test) peak flows for future high-flow 

5 experiments have been ongoing during recent planning activities. There are many factors 

6 to consider related to peak-flow duration and peak magnitudes for high-flow experiments 

7 (see table A.2). 

8 Issue: Is there a risk of a potential take or impact (of a future BHBF test) on 

9 juvenile humpback chub? HBC recruitment? 

10 Based on the spring season for future BHBF tests and the results of fisheries 

11 studies conducted in association with the 1996 BHBF experiment in Grand Canyon, there 

12 appears to be little risk to juvenile humpback chub associated with future proposed spring 

13 BHBF experiments. The abundance of juvenile humpback chub in the mainstem 

14 Colorado River is driven, in part, by freshet events in the Little Colorado River. Because 

15 the proposed timing of future BHBF experiments is generally tied to late March, 

16 scientists at the GCMRC expect few freshet events and therefore few juvenile humpback 

17 chub to be present in the mainstem Colorado River. This alone will reduce the number of 

18 humpback chub vulnerable to potential displacement or mortality because of future 

19 spring BHBF experiments. Following extensive sampling to measure abundance of fish 

20 before and after the spring 1996 BHBF experiment, catch-rate metrics showed 

21 insignificant differences before and after the experiment for most fish (Valdez and others, 

22 2001). The exceptions were a significant decrease in the abundance of small bodied 

23 nonnative fish and a significant increase in the abundance of speckled dace. Additionally, 

24 results from telemetry and diet work suggest minimal behavioral or feeding disruptions of 

25 adult humpback chub and flannelmouth sucker associated with the spring 1996 BHBF 

26 experiment. Relative abundance of juvenile native fish was also estimated before and 

27 after the 2004 BHBF experiment downstream of the Little Colorado River confluence 

28 (GCMRC unpublished data; Coggins and others, 2005). Unfortunately, the results of the 

29 fall 2004 study were highly inconclusive owing to elevated turbidity following that 2004 

30 BHBF test because of flooding activity in the Little Colorado River. These conditions 

31 rendered catch-rate observations taken before and after the experiment unreliable owing 

32 to likely changes in sampling gear efficiency. 

33 The findings associated with the 1996 high-flow experiment that native fish are 

34 little affected by high-flow events are consistent with theory and other published studies. 

35 Meffe (1984) found that adapted native fish species tolerated elevated discharge 

36 associated with freshets better than introduced species. Indeed, this differential tolerance 

37 to flooding has been suggested as a nonnative control method (Minckley and Meffe, 

38 1987). Though these studies view high discharge events as potential displacement 

39 mechanisms rather than direct sources of mortality, there is no evidence that humpback 

40 chub recruitment would be directly hindered by a future BHBF experiment. On the 

41 contrary, one hypothesis is that potential humpback chub recruits might enjoy higher 

42 survival rates because of increased food resources (see experimental study 3 description, 

43 this plan) and decreased negative interaction with nonnative fishes (Valdez and others, 

44 2001). Though it is certainly valid to hypothesize that a BHBF experiment could hinder 
 68

1 recruitment by imposing some direct or indirect mortality source, there is presently 

2 insufficient data to arbitrate among these competing hypotheses. 

3 Issue: Concerns about insufficient funds to address HBC issue (relative to BHBF 

4 testing)? 

5 The GCMRC believes that funding is not the major impediment to studying the 

6 effects of a high-flow experiment on humpback chub. The major challenge is attempting 

7 to evaluate changes in distribution and fate of humpback chub without the appropriate 

8 techniques and/or technology to field a viable study (see Appendix B). 

9 Issue: Will there be negative impacts (from future BHBF testing) to the food base? 

10 Will it clean or refresh the system? 

11 We are uncertain about these important questions. While we know that the 

12 biomass (a static measure) of food base components are temporarily reduced following a 

13 BHBF experiment, little is known about the effect of a BHBF experiment on their 

14 productivity (a dynamic process measure). Our working hypothesis is that after the initial 

15 reduction in food following a BHBF test, daily production and turnover of algae, 

16 invertebrates, and possibly fish are higher than pre-BHBF testing conditions. This 

17 positive response by the food base may offset the negative initial effects such that there is 

18 little net loss of material and productivity when viewed on slightly longer time scales 

19 (months to a year). This knowledge gap is precisely why we must do more experimental 

20 high-flow tests to pin down quantitative answers for the important questions raised 

21 above. 

22 

23 Issue: What are the impacts (of a future BHBF test) to hydropower and other 

24 economic interests (i.e., fishing guides and river guides)? 

25 

26 Specific studies to assess the economic impacts of conducting future BHBF 

27 experiments have not been conducted and can not be definitively determined with 

28 available information. Based on the recent economic assessment by the Western Area 

29 Power Administration for the experimental options study (conducted in 2006 by the 

30 AMWG’s Science Planning Group), there would be some short term but significant 

31 economic impacts for hydropower in the form of lost revenue generation opportunities 

32 (loss of potential marketable power because of water bypassing the generators during 

33 future BHBF testing). There would also be some immediate short-term gains resulting 

34 from running the generators at full capacity during future BHBF experiments, though not 

35 sufficient to offset future lost opportunity costs. In terms of recreational economic 

36 interests, there are likely to be short-term impacts to the local fishing guide economy 

37 during and probably immediately following future BHBF tests. Based on the proposed 

38 timing and duration of the event, however, and considering the hypothesized response of 

39 the aquatic food base over the long term (short-term decline followed by relatively rapid 

40 rebound and potentially increased productivity), the economic impact to recreational 

41 fishing is uncertain and yet to be studied. Projected economic impacts to commercial 

42 river runners, on the other hand, are likely to be very minimal to non-existent, because 
 69

1 the proposed timing of a future BHBF experiment is before the start of the commercial 

2 boating season. The larger question that remains to be determined, and that is most 

3 critical for assessing the overall economic implications of a high-flow experiment, is 

4 whether the combined potential economic impacts of conducting a BHBF experiment 

5 outweigh the potential resource benefits and societal value derived from conducting the 

6 experiment. Unfortunately, the GCDAMP is currently lacking up-to-date, comprehensive 

7 valuation data with which to address this larger economic question. 

8 Issue: BHBF experiments result in a lot of sediment below Diamond Creek, 

9 resulting in economic concerns for the Hualapai Nation. Additionally, there is an 

10 archeological site below Glen Canyon Dam that going to be harmed and unless 

11 there is a plan for that site. 

12 In recent years, with the lowering of Lake Mead because of drought and ongoing 

13 water withdrawal, formerly submerged sand deposits at the head of Lake Mead have 

14 become increasingly shallow, creating serious challenges for down-lake navigation. Also, 

15 the exposure of formerly submerged sandbars has cut off access to a formerly popular 

16 take-out point at Pierce Ferry. The Hualapai Tribe is concerned that a high-flow 

17 experiment could exacerbate these current problems by displacing sand from the main 

18 channel into areas used as harbors and launch sites by their boat operators. At Diamond 

19 Creek and other eddies immediately downstream, sand is very likely to be transferred into 

20 the eddies (this is why BHBF tests build sandbars and benefit camping beaches.) 

21 Assuming the lake remains low, a BHBF test released into Lake Mead is also likely to 

22 generate a strong current in the upper part of the lake, which would remobilize some of 

23 the channel-clogging sediment and help to redefine a clear channel through the sandbars 

24 in the upper part of the lake, but whether and to what degree sediment would be re25 deposited in specific shoreline locations used by the Hualapai Nation tour operators, and 

26 whether it would have negative consequences for these commercial operations, is 

27 unknown. What is known with certainty is that a short-term BHBF experiment will not 

28 solve, nor will it significantly exacerbate, the long-term issue of sediment build up in 

29 upper Lake Mead, with its concomitant implications for future navigability. 

30 The second part of the comment expresses concern about possible negative 

31 impacts of a high-flow experiment to archaeological sites, particularly one site located in 

32 the Glen Canyon reach. In 1996, before the first BHBF experiment, the Bureau of 

33 Reclamation funded a series of studies to evaluate and mitigate potential effects of high34 flow experiments on cultural sites in the river corridor. Following completion of these 

35 compliance-driven studies, the Arizona State Historic Preservation Office issued a formal 

36 determination of "no adverse effect" for experimental flows up to 60,000 cfs (Nancy 

37 Coulam, personal comm., December 7, 2007.). Recently, a team of archaeologists and 

38 one geomorphologist from the Navajo Nation Archaeology Department (NNAD) 

39 completed a geomorphic evaluation of all archaeological sites in the Glen Canyon reach, 

40 and they concluded that one site (AZ C:2:32) has the potential to be eroded by a future 

41 BHBF test. During the 1996 mitigation work, there was considerable uncertainty as to 

42 whether this site was truly cultural, but the recent re-evaluation by NNAD confirms that 

43 this is a potentially significant archaeological site containing deposits dating to the late 

44 Archaic period, approximately 3,000 years BP. The NNAD archaeologists recommend 

45 that a portion of this threatened site adjacent to the river be excavated before conducting 
 70

1 a future BHBF experiments. A draft mitigation plan has been prepared for the Bureau of 

2 Reclamation to implement, if warranted. The author of this draft plan estimates that 

3 mapping and excavation of the site could be accomplished over two 10-day field sessions 

4 with an 8-person crew (Kim Spurr, personal comm., January 22, 2007.) 

5 Issue: Time is constrained by the possibility of one dam unit being down for 

6 maintenance after March. 

7 From our understanding of the proposed annual maintenance schedule at Glen 

8 Canyon Dam, we do not see a problem with having one of the eight turbine units at the 

9 dam non-operational annually through March during proposed, future BHBF 

10 experiments, although having eight units fully operational would be optimal for sediment 

11 studies. Future BHBF experiments are not currently proposed for later than March. 

12 
 71

1 Table A.1. Summary of pros and cons associated with conducting future BHBF Tests2 

GENERAL CONCERNS PROS CONS UNC

AMP RESOURCES 

• Sandbar restoration and 

conservation of related physical habitats 

• Improvement of recreational 

camping sites 

• Preservation of some archeological 

sites through secondary wind deposition 

• Creation of backwater habitats used 

by native fishes 

• Mimics seasonal flood disturbance 

to river ecosystem 

• Lost hydropower capacity and 

revenue owing to bypass and monthly volume re-scheduling 

• Impact to cultural site in Glen 

Canyon (to be mitigated) 

• Impact to Kanab ambersnail habitat 

(endangered species) at Vaseys Paradise (to be mitigated) 

• Increased use of motorized 

watercraft during Colorado River Management Plan non-motor season in Grand Canyon National Park that can be mitigated through public outreach) 

• Aquatic f

• Impacts a

humpbac

• Impacts o

• Impacts o

terrestrial 

SCIENCE (Learning by Doing) 

• Advances learning about options for 

achieving GCDAMP Priority Goals, especially sediment, trout fishery, food base, cultural resources and riparian habitat 

• Provides information about optimal 

BHBF hydrograph design to maximize benefit and minimum costs? 

• Informs interested public • Information transfer to other 

scientists and managers working on river restoration 

• None • None 
 72

EXP BUDGET 

• Credible subset of studies can be 

implemented to address highpriority needs 

• Available funding is currently 

insufficient to implement all proposed studies 

• None 

ECONOMIC 

• Infusion of local economic activity 

linked to science support, etc. 

• Foregone hydropower capacity in 

later timeframe (to be quantified by Bureau of Reclamation and Western Area Power Administration) 

• Potential short-term disruption of 

Lees Ferry angling recreation 

• Financial 

quantified 

• Non-use 

resource 

INFLUENCE ON ANNUAL WORK PLAN 

• Shifts emphasis from solely 

monitoring to EXP research learning activities in a given year 

• New information will better inform 

GCDAMP process 

• Number of non-experimental 

planned activities will need to be delayed/deferred 

• Impacts timing of some normal 

monitoring activities 

• Full impa

annual wcomplete

NO HIGH-FLOW EXPERIMENTS (BHBF) ALTERNATIVE (SCIENCE/RESOURCE PERSPECTIVE) 

• Would not impact annual work plan 

tasks of monitoring 

• Monitoring data on downstream fate 

of new sand supplies under modified low fluctuating flow (MLFF) 

• No hydropower impacts 

• No opportunity to benefit sand and 

related physical habitats resources (such as backwaters and possible benefit to juvenile humpback chub)

• Already have abundant data on 

export of sand under MLFF, hence little new learning would occur

• No opportunity to learn more about 

how BHBFs may limit sand export under fluctuating flows that follow

• Missed opportunity to gather data on 

BHBFs as related to strategic, experimental questions about sand conservation and effectiveness of 

BHBFs to meet Goal #8 objectives

• BHBFs are dependent on meeting 

the sediment input trigger

• There is g

when contrigger an experimesand inpucannot be 

1 2 
 73

1 Table A.2. Comparison of 60-hour to 30-hour peak duration BHBF Test at 45,000 cubic feet per second (cfs) 2 

High-flow peak duration at 41,500 cfs ~ Glen Canyon Dam bypass volume 

(Hours) 

PROS 

OPTION A 60 hours (as determined by BHBF model simulations and recommended by sediment scientists) 

~ 93,000 acre feet (91 hours) 

• Provides most rigorous direct 

comparison with 2004 BHBF test data 

• Maximum sandbar restoration 

predicted from modeling to occur in this timeframe 

• Resulted in net positive sand 

balance in 2004 BHBF test 

• Allows field scientists time for 

replicate eddy and SS measurements 

• 108 hours shorter than 1996 

BHBF test 

• Greatest influence on 

exporting low oxygen from hypolimnion of Lake Powell 

• Byp

sugg

• High• High

user

OPTION B 30 hours (alternative BHBF test hydrograph) 

~ 56,000 acre feet (61 hours) 

• Reduces bypass volume • Reduced impact on 

hydropower 

• Reduced impact on 

recreational users 

• Reduces potential export of 

new sand supply relative to option A 

• Pote

dowresto

• Lim• Shor

less low of L

3 

 75

1 References Cited 

2 

3 Coggins, L., Yard, M., Persons, B., Van Haverbeke, R, and David, J., 2005, Results of hoopnet 

4 sampling to examine changes in juvenile humpback chub abundance and size before and after the 

5 2004 experimental high flow: presentation to the Adaptive Management Workgroup, March 3, 

6 2005, http://www.usbr.gov/uc/rm/amp/amwg/mtgs/05mar02/documents/Attach_07h.pdf 

7 

8 Meffe, G.K., 1984, Effects of abiotic disturbance on coexistence of predator-prey fish 

9 Species: Ecology, v. 65(5), p. 1525–1534. 

10 

11 Minckley, W.L., and Meffe, G.K., 1987, Differential selection for native fishes by flooding in 

12 streams of the arid American Southwest, in Matthews, W.J., and Heines, D.C., eds., Ecology and 

13 evolution of North American stream fish communities: Norman, Oklahoma, University of 

14 Oklahoma Press, p. 93–104. 

15 

16 Valdez, R.A., Hoffnagle, T.L., McIvor, C.C., McKinney, T., and Leibfried, W.C., 2001, 

17 Effects of a test flood on fishes of the Colorado River in Grand Canyon, Arizona: 

18 Ecological Applications, v. 11(3), p. 686–700. 
 76

1 Appendix B: Factors Influencing the Design of BHBF Related Experimental 

2 Studies for Fisheries, Cultural Resources, and Water Quality 

3 Fisheries Studies Associated with Future BHBF Tests 

4 The use of BHBFs was identified in the 1995 Operation of Glen Canyon Dam Final 

5 Environmental Impact Statement (EIS) as a strategy to conserve sediment resources tied to 

6 physical, nearshore habitats thought to be important to native fish in the mainstem Colorado River 

7 below Glen Canyon Dam. Short-term experimental releases have previously been reported to have 

8 limited immediate influence on long-lived fishes (Valdez and others, 2001). It is still unclear what 

9 role the abundance, size, and distribution of nearshore sandbar features, such as backwaters, play in 

10 the life history of humpback chub in the CRE. Evaluating complex and multiyear fish responses 

11 that might be associated with short-duration, high-flow experiments that occur infrequently (mostly 

12 designed with sediment studies in mind) is difficult. Simply put, the capture and enumeration of 

13 rare fishes in a large, turbid river are difficult tasks that, despite recent advances, continue to be 

14 associated with high uncertainty. 

15 The GCMRC and its cooperators continue to work on this problem and are improving both 

16 the capture and estimation techniques for the rare native fishes, especially humpback chub. Because 

17 of the high level of interest in these species, monitoring for humpback chub and other native fishes 

18 occurs throughout the year annually (illustrated by the 2007 work plan summarized in table C.1), 

19 providing a long-term perspective of the status and trends of these populations. Such a sampling 

20 regimen will bracket a future BHBF test whenever it is scheduled and provide a valuable, long-term 

21 perspective on the fate of humpback chub and other native fishes. 

22 
 77

1 Table B.1. Native fish monitoring below Glen Canyon Dam in 2007. 

Project Timing Primary Objective 

Downstream Native Fishes March Monitor native fishes from Lees 

Ferry to Diamond Creek (spring) 

Little Colorado River Humpback 

Chub 

April Population estimate of humpback 

chub in the LCR (concurrent 

sample) 

Little Colorado River Lower 

1200 meters/PIT tag antennae 

April-May Intensive monitoring of 

humpback chub in lowest 1200 

meters of the LCR/test remote 

PIT tag antennae 

Downstream Native Fishes April Population estimate of humpback 

chub in the mainstem Colorado 

River (concurrent sample) 

Little Colorado River Humpback 

Chub 

May Population estimate of humpback 

chub in the LCR (concurrent 

sample) 

Downstream Native Fishes May Population estimate of humpback 

chub in the mainstem Colorado 

River (concurrent sample) 

Above Chute Falls June Monitor the translocated 

population of humpback chub 

upstream in the LCR 

Warm Water Fishes/Sonic Tags June Monitor channel catfish in lower 

Colorado River/test application of 

sonic tags 

Above Chute Falls June-July Monitor the translocated 

population of humpback chub 

upstream in the LCR 

Downstream Native Fishes March Monitor native fishes from Lees 

Ferry to Diamond Creek 

(autumn) 

Backwater Monitoring September-October Monitor small-bodied fishes in 

near-shore habitats, primarily 

backwater eddies 

Little Colorado River Humpback 

Chub 

September Population estimate of humpback 

chub in the LCR 

Little Colorado River Humpback 

Chub 

October Population estimate of humpback 

chub in the LCR 

2 

3 

4 Fisheries scientists attempted to evaluate changes in distribution of native and nonnative 

5 fishes using catch-rate metrics from conventional sampling gear (e.g., hoopnets, electrofishing, 

6 etc.) used during the 1996 and 2004 BHBF tests. This common strategy was based on the 

7 assumption that catch-rate (number of fish captured per each unit of sampling effort) is directly 

8 proportional to fish abundance. However, this assumption will be violated if the efficiency of the 

9 sampling gear (catchability) is substantially affected by any uncontrollable variables (e.g., 

10 temperature, turbidity; reviewed by Arreguin-Sanchez, 1996). Therefore, comparisons of catch rate 

11 before and after an event like a future BHBF test are only valid to infer changes in abundance if it 

12 can be safely assumed that catchability was equal between the two samples. Violations of this 

13 assumption are particularly problematic when comparisons are made between only two events as 
 78

1 opposed to inferring trend in abundance from a extensive time-series data where variability in 

2 catchability can sometimes be taken into consideration. Additionally, catch-rate estimates for rare 

3 fishes are frequently estimated with low precision. This is clearly illustrated considering the results 

4 of the 1996 BHBF test (Valdez and others, 2001). Careful inspection of these results suggests that 

5 for the rare species the statistical power to detect change is very low. 

6 A further problem with this type of study is that displacement does not necessarily imply 

7 mortality. For instance, even if the decline in catch rate associated with the 2004 BHBF test 

8 (GCMRC, unpublished data; Coggins and others, 2005) was related to a change in abundance 

9 rather than a change in catchability, it is unknown whether the change in abundance was because of 

10 mortality. It is also possible that this change is simply a result of fish using different habitats 

11 following the 2004 BHBF test or that downstream displacement was temporary. Regardless of 

12 which of these hypotheses is correct, this type of study cannot ultimately provide information on 

13 the fate of fish associated with a future BHBF test. Therefore, we conclude that new techniques are 

14 required to answer the recurring question asked by managers, namely: “What is the fate of juvenile 

15 native fish during a future BHBF test?” 

16 We propose that direct measurement of individual fish movement, accomplished through 

17 telemetry studies, would be the most conclusive method for inferring the fate of fish associated 

18 with a future BHBF test. Telemetry techniques have advanced substantially in the last decade and 

19 we are considering their use to investigate a host of fisheries related questions (see section 2, 

20 experimental study 4.B). However, using telemetry requires substantial training and trial 

21 applications. We are currently engaged in trials of this technology and initial results are 

22 encouraging. 

23 Historically, the Lees Ferry reach has provided an ideal environment for the application of 

24 new technologies, suggesting a high probability of success. This owes, in part, to the ease of 

25 logistics, the small spatial scale, and the presence of large numbers of study animals (rainbow trout) 

26 in a relatively clear aquatic environment. Experimental study 4.B proposes to study the effects of a 

27 BHBF test on the distribution of juvenile and adult rainbow trout in the Lees Ferry reach using both 

28 indices of abundance and acoustic telemetry (this gear is being studied in 2007; see table 1). A 

29 study of this nature has a high probability of success for multiple reasons. One benefit of launching 

30 this type of study in the Lees Ferry reach is that working with rainbow trout provides ample study 

31 organisms that can be collected with little effort. This not only promotes the ability to detect small 

32 experimental effects but also incurs modest logistical costs. Alternatively, attempting such a study 

33 for humpback chub would likely require a large effort and cost to attain enough organisms. This 

34 would be difficult given the proposed timing of a BHBF test because juvenile humpback chub are 

35 at their highest abundance in the mainstem Colorado River during and after the monsoon season 

36 (mid to late summer) but far fewer fish are expected to be available for study in November–March 

37 (the likely timing of future BHBF tests). 

38 The mortality risk associated with telemetry studies on juvenile rainbow trout is less than 

39 that for juvenile humpback chub because of the broad experience with surgical techniques for 

40 juvenile salmonids. The GCMRC and associated cooperators have experimented with sonic 

41 telemetry equipment in the Lees Ferry reach to determine its effectiveness under those specific 

42 conditions. Initial experimentation was very successful in that experimental sonic tags could be 

43 readily tracked in the Lees Ferry reach. 

44 Sonic tags will be tested further in 2007, under more demanding conditions, especially in 

45 the presence of higher turbidities than occur in the Lees Ferry reach. The value of the sonic tag 

46 technology to the GCDAMP will increase if it can be shown to perform well under the more turbid 
 79

1 conditions of the Little Colorado River inflow and below Diamond Creek. Investigators will also 

2 gain expertise with implanting these tags in 2007. If the tags are still detectable in turbid conditions, 

3 and if investigators achieve good survival rates for fish implanted with the tags during 2007 studies, 

4 the GCMRC will propose that this technology be used with individual humpback chub, subject to 

5 regulatory agency approval. The 2007 results, and results in future years, will help determine the 

6 minimum size of humpback chub that would be proposed for tagging and tracking; however, there 

7 is general agreement among the cooperators that younger, smaller fish are of greatest concern and 

8 therefore would be most important to track. Specific recommendations for use of sonic tag 

9 technology, including an associated budget, will be prepared, reviewed, and distributed at least 120 

10 days in advance of a proposed future BHBF test. 

11 The thoughtful review of the GCDAMP Science Advisors clearly articulates the opinion 

12 that additional work on humpback chub should be a priority associated with future experimental 

13 high flows. We attempted to highlight the problems and shortcomings associated with fish 

14 sampling and monitoring connected with past experimental high flows and outline our approach to 

15 overcoming these issues using telemetry (see above). Subsequently, we have also identified a 

16 relatively new set of estimation techniques that could also allow better inferences about the effects 

17 of experimental high flows on humpback chub than index-based methods used in the past. 

18 Since 2000, much work has been done to characterize change in fish population size, 

19 distribution, and habitat use in situations where it is not practical to estimate or index abundance 

20 (Mackenzie and others, 2006). These newly developed techniques hold promise for quantifying 

21 change in fish density and habitat use before and after an experimental BHBF. The basic idea is 

22 that rather than comparing abundance indices (such as catch per unit effort) before and after some 

23 event where the critical assumption of equal capture probability is typically not testable, occupancy 

24 models estimate not only the proportion of sampling units occupied, but also the detection 

25 probability. As such, probability of occupancy becomes a comparable state variable between, for 

26 instance, two time periods. If sampling units are further grouped by a covariate such as habitat type, 

27 occupancy rates become a measure of habitat use. Finally, since detection probability is likely 

28 influenced by abundance, methods have also been developed to extract abundance. 

29 We are intrigued by this novel approach because of its potential for monitoring small30 bodied fish. We plan to analyze several existing datasets, including the data collected in association 

31 with the 2004 BHBF test, and conduct simulation studies using this technique to evaluate its use in 

32 estimating fishes before and after any future BHBF tests. Pending these evaluations, we may 

33 propose further sampling to estimate occupancy and associated parameters to better understand the 

34 effects of experimental high flows on humpback chub. If these methods are shown to be applicable 

35 for use in Grand Canyon, then we would propose to add a project for occupancy estimation for 

36 humpback chub in association with a BHBF test. This proposal and associated budget would be 

37 submitted for consideration at least 120 days before a proposed future BHBF test. 

38 Summary of Challenges in Assessing the Effects of Future BHBF Tests on 

39 Native Fish Populations in the Colorado River in Grand Canyon 

40 Trends in Fish Abundance in Glen and Grand Canyon 

41 

42 • Humpback chub abundance in Grand Canyon, based on catch-per-effort (CPE) and tagging 

43 assessments, shows continuing decline through the 1990s. Trends in adult abundance 
 80

1 observed during the 1990s suggest recruitment of young humpback chub began declining by 

2 the mid-1980s 

3 • Reductions in daily fluctuations and increased minimum flows beginning in the early 1990s 

4 likely caused the large increases in rainbow trout in Glen Canyon and in Grand Canyon near 

5 the Little Colorado River confluence where humpback chub are most abundant 

6 • There is considerable uncertainty about the cause of the decline in humpback chub 

7 recruitment – timing of the recruitment decline in mid-1980s does not match the timing of 

8 the rainbow trout increase in mid-1990s, though increasing rainbow trout may have 

9 continued to suppress the humpback chub population 

10 

11 Glen Canyon Dam Treatments Targeted at Improving HBC Recruitment 

12 

13 • The 1996 Biological Opinion for the EIS recommended modifications to Glen Canyon Dam 

14 operations designed to restore some elements of downstream physical habitat for humpback 

15 chub: 

16 o Seasonally adjusted steady flows to increase shoreline habitat stability and increase 

17 water temperature to stimulate mainstem spawning and improve juvenile survival 

18 rates 

19 o Testing of thermal modification of releases from Glen Canyon Dam 

20 • These hypotheses were based on very limited data at the time they were formulated. 

21 Impacts of fluctuating flows on humpback chub recruitment are not supported by the timing 

22 of decline in humpback chub abundance and increase in rainbow trout abundance. 

23 • The most recent experimental flow treatment recommended by the Glen Canyon Dam 

24 Adaptive Management Workgroup called for increased daily flow fluctuations (5,000–

25 20,000 cfs) from January–March in 2003 and 2004. The increase in daily fluctuations was 

26 intended to limit rainbow trout abundance and associated negative interactions with 

27 humpback chub. 

28 • BHBFs to rebuild nearshore sandbar habitats were also described as part of the 1996 ROD 

29 and additional sediment tests were recommended by the GCDAMP as part of integrated 

30 physical and biology experimentation in 2002. A second BHBF experiment was then 

31 conducted in fall 2004 when the Paria River delivered new sand to the ecosystem in Marble 

32 Canyon. 

33 • The potential for improving our understanding of the effects of dam operations, particularly 

34 BHBFs, is limited by: 

35 o Assessments of juvenile abundance based on catch rate metrics (CPE) are difficult to 

36 interpret because of uncontrollable changes in gear efficiency (catchability), 

37 particularly for fishes in low abundance and over short time intervals (e.g., BHBF) 

38 o Tagging assessments are more reliable than CPE data, but there is a long (3+ years) 

39 lag between the time a change in recruitment occurs and when it can be observed 

40 using the tagging assessment data. The occupancy estimation models being 

41 investigated by GCMRC and others may be employed to help address earlier life 

42 stages 

43 o Imprecision in all available assessment methods makes it difficult to detect year-to44 year differences in recruitment unless they are extremely large 
 81

1 o Experimental flows need to be replicated over multiple years to account for 

2 environmental variability and the limitations in available assessment methodology 

3 o The short-term single-year approach to experimental management currently adopted 

4 by the AMWG greatly reduces the chance of measuring native fish responses and 

5 does not embrace recommendations from the broader scientific literature on adaptive 

6 management experimental design. Further, the natural variability of annual sand 

7 production from the tributaries and other considerations typically means that future 

8 BHBF tests are likely to occur relatively infrequently under sand-enriched 

9 conditions and that annual replication is unlikely. 

10 

11 Evaluating the status and trends of native and nonnative fish populations in Grand Canyon is 

12 extremely difficult because of sampling logistics and the low abundance of native fishes, especially 

13 in the early months of the year. Application of stock assessment modeling procedures, originally 

14 developed for managing commercial fisheries, has been helpful for estimating population trends 

15 from the historical fisheries data (Coggins and others, 2006), but tagging based assessments involve 

16 considerable lag time before reliable assessments of recruitment responses to management actions 

17 are available. However, the sonic tagging of fish being studied by GCMRC and cooperators has the 

18 potential to provide some short-term information on individual fish movements. Tagging will be 

19 especially valuable if it proves to be useful in evaluating whether native fishes displaced by 

20 temporary high flows retain the ability to return to an area following the flows. Tagging methods 

21 are generally not sufficient to resolve whether declines in native fish populations have been caused 

22 by the increasing abundance of exotic fishes, dam operations (including BHBFs), or a combination 

23 of the two. Our ability to detect fish population responses to future BHBF tests is limited in spite of 

24 the lessons learned from stock assessment modeling and expanded monitoring efforts. Additional 

25 methods are needed and are currently under development by GCMRC and cooperating agencies, 

26 especially Arizona Game and Fish Department. 

27 

28 Cultural Resources 

29 Future BHBF tests have the potential to change ecosystem dynamics in ways that may 

30 affect the condition and biophysical attributes of many culturally important resources located in the 

31 Colorado River corridor, including archaeological sites, traditional cultural properties, and 

32 individual species of special concern to Native American tribes. Additionally, future BHBF tests 

33 may alter camping beaches used by park visitors and other ecosystem attributes that influence the 

34 quality of the visitors’ experience (e.g., navigability of rapids, abundance and distribution of 

35 rainbow trout.) For example, it has been hypothesized that the periodic replenishment of sandbars 

36 above the level of normal Record of Decision flows reduces crowding and competition for 

37 campsites, thereby improving the quality of visitor experience. It has also been hypothesized that 

38 the creation of larger, higher, and drier sandbars as a result of periodic high flows increases the 

39 available sediment sources for aeolian transport to higher elevations in the ecosystem, thereby 

40 potentially offsetting some of the ongoing erosion of archaeological sites caused by rainfall run off, 

41 social trailing, and surface deflation. 

42 The science activities described in this plan explicitly integrate several important cultural 

43 concerns within individual study plans in recognition of the close interrelationship between 

44 physical and biological processes and resource condition outcomes. Specifically, proposed science 

45 activities are designed to evaluate the potential effects of future BHBF tests on sediment transport 
 82

1 and deposition at archaeological sites and consequent effects to the sites’ stability or erosion; 

2 evaluate the size and distribution of sandbars and open sand area used as camping sites and their 

3 persistence through time; trout dispersal in response to future BHBF tests; and the distribution of 

4 native and nonnative riparian species, many of which are culturally important to local Native 

5 American tribes. 

6 Most of the proposed BHBF studies are designed to build upon monitoring data that are 

7 already being collected to assess the rate and extent of changes occurring to the ecosystem under 

8 Record of Decision operations. For example, in conjunction with developing an ecosystem-based 

9 approach to monitoring archaeological site condition, the GCMRC has established weather 

10 monitoring stations and is collecting aeolian transport and gully erosion data at a sample of 

11 archaeological sites within the Colorado River ecosystem. Data from focused science activities 

12 proposed as part of this experimental BHBF science plan, (experimental study 1.C) would be 

13 analyzed in relation to these previously collected monitoring data. Likewise, the GCMRC annually 

14 collects data on the area, volume, and extent of available campable area at selected sandbar sites 

15 distributed throughout the Colorado River ecosystem; additional survey data and documentation 

16 collected in conjunction with a future BHBF test will be analyzed in relation to these pre-existing 

17 monitoring data. 

18 This science plan targets a limited set of key questions and issues that have been 

19 consistently identified by resource managers and GCDAMP stakeholders as being most critical to 

20 study through implementation of future BHBF tests. Future BHBF testing and associated science 

21 activities are designed to improve understanding of the geomorphic and biological effects of BHBF 

22 tests conducted under sediment-enriched conditions as they relate to the goal of improving the 

23 potential for in situ maintenance and protection of culturally valued resources, in keeping with the 

24 stated intent of the GCDAMP. This information will have direct relevance to ongoing resource 

25 management and legal compliance issues. 

26 Water Quality 

27 Any investigation of the dynamics of the Colorado River ecosystem in Grand Canyon must 

28 not only document and understand the water quality in Grand Canyon itself, but also the water 

29 quality in Lake Powell, the reservoir created by Glen Canyon Dam. The impoundment of a river 

30 system in a reservoir alters downstream water quality in many ways (Nilsson and others, 2005). 

31 The formation of Lake Powell in 1963 was accompanied by reductions in suspended sediment and 

32 nutrient transport and by changes in seasonal temperatures, discharge levels, and benthic 

33 community structure of the Colorado River (Paulson and Baker, 1981; Stevens and others, 1997; 

34 Topping and others, 2000a; 2000b). More recently, reservoir and downstream water quality has 

35 been affected by reservoir drawdown from a 5-year basinwide drought in the Western United 

36 States. Water released from Glen Canyon Dam in 2003 and 2004 was the warmest recorded since 

37 August 1971, when Lake Powell was in its initial filling period (initial filling of the reservoir began 

38 in 1963 with the closure of Glen Canyon Dam; the reservoir reached full pool of 3,700 ft for the 

39 first time in 1980). 

40 Water temperature, nutrient concentrations, turbidity, and other water-quality parameters 

41 are of interest to managers and scientists because these parameters influence a range of ecosystem 

42 components, from support of aquatic microorganisms and invertebrates to the behavior of native 

43 and nonnative fishes. For example, water quality is an important determinant of food-web structure 

44 in aquatic habitats and abundance of consumers like fish in those food webs (Carpenter and 

45 Kitchell, 1996; Wetzel, 2001). 
 83

1 Scientists hypothesize that operational changes associated with any future BHBF tests could 

2 have significant effects on the quality of water released from Glen Canyon Dam. The experimental 

3 work proposed in this science plan will measure changes in water-quality characteristics for the 

4 water leaving the dam and the water in the tailwaters during and immediately following a future 

5 BHBF testing. 

6 

7 

8 References Cited 

9 

10 Coggins, L.G., Pine, W.E., III, Walters, C.J., Van Haverbeke, D.R., Ward, D., Johnstone, H.C., 

11 2006, Abundance trends and status of the Little Colorado River population of humpback chub: 

12 North American Journal of Fisheries Management, v. 26, p. 233–245. 

13 

14 Topping, D.J., Rubin, D.M., Schmidt, J.C., Hazel, J.E., Jr., Melis, T.S., Wright, S.A., Kaplinski, 

15 M., Draut, A.E., and Breedlove, M.J., 2006, Comparison of sediment-transport and bar-response 

16 results from the 1996 and 2004 controlled-flood experiments on the Colorado River in Grand 

17 Canyon, in Federal Inter-Agency Sedimentation Conference, 8th, Reno, Nevada, 2006, CD-ROM 

18 Proceedings (ISBN 0-9779007-1-1). 

19