GCMRC Responses to the SA comments on the Science Plan for Potential 2008 Experimental 

High Flow At Glen Canyon Dam, dated January 13, 2008. 

The following are in response to the overall comments: (SA comments are in 

italics) 

Impacts to the HBC may be avoided by a lack of movement of yoy out of the LCR. However, 

could winter storm events jeopardize this setting? 

Response: Winter storm flows may impact limited numbers of native fishes. No season of the 

year will entirely avoid potential impacts, but March is one of the months with the lowest 

probability of such events, so we expect impacts to be minimal. 

Benefits to HBC are to be assessed from backwaters. However, it is unclear how benefits will 

be realized from this test. 

Response: The current high flow test plan and ongoing GCDAMP work plan will assess benefits 

to humpback chub indirectly, predominantly in two ways. First, we will measure backwater 

attributes, including primary and secondary production and temperature, to tell us if there are (at 

least temporary) favorable conditions for humpback chub in these habitats. Secondly, we will 

continue the ongoing monitoring of the humpback chub population to continue the long-term 

assessment of the status and trends of this species in Grand Canyon. 

...more information is needed to structure and test effective hypotheses [about backwaters] in 

this high flow event. 

Response: We intend to apply significant time and other resources to the study of backwater 

habitats in 2008, hopefully taking advantage of the infrequent high flows in Grand Canyon that 

create sand bar backwaters. We are in the process of developing a new study (planned to be 

released for open competition) that will study other near shore habitats, as well as backwaters. 

We have termed this new study the near shore ecology study. 

...we doubt the hydrograph historically peaked as early as March each year. 

Response: We agree. In the new, altered environment that is Grand Canyon today, we believe 

February or March are the best months to have a positive impact on as many resources as 

possible, while minimizing negative impacts. No one month will be perfect for all resources 

considered. For example, a modern high flow in June, historically the month when the spring 

runoff peaked in Grand Canyon, would, today, be an excellent opportunity to broadly spread 

tamarisk seed in the canyon. 

Methods (p. 38) state that an effort will be made “to assess as many backwaters as 

possible.”...sampling bias could be a problem. 

Response: We remain very interested in measuring as many of the backwater habitats created by 

sandbars as possible. We believe we have developed an approach to doing this. We will use data 
generated by surveyors using total stations on projects 1C and 1D. Surveyors working on 1D will 

be working from a prioritized site list. Prioritization factors include: previous humpback chub 

capture locations, backwaters near humpback chub aggregations, geomorphic reaches, and sites 

previously mapped in overflights (2002 and 2005). For those sites that cannot be surveyed in this 

manner due to time constraints, we will measure those habitats with tape measure and level. We 

expect to measure all, or nearly all, backwater habitats with at least one method. 

Page 5, para. 3: It refers to Figure 3 as evidence that humpback chub populations increased 

in the period 1994 to 2000. However, this figure shows overlapping confidence intervals at the 

95% level. Thus, the statement doesn’t seem very credible. 

Response: Figure 3 shows the trend in humpback chub recruitment to adulthood, not the adult 

population size, which is shown in Figure 4. However, the confidence interval concern expressed 

by the reviewer could apply to both figures. It is important to note that these are not the results of 

pooled field samples, or some other sampling, but are the results of model simulations based on 

field collections. The simulations are randomized and re-run 1,000 times to test for departure 

from random. Despite the modest amount of overlap between maximum values from one year 

and minimum from the next, we think the risk of in incorrect conclusion about the population is 

extremely small. In other words, the trend in the adult population from 2001 to 2006 is 

increasing, in all likelihood. There is some risk to this being an incorrect statement, but we, and 

our exterior reviewers, thought that this risk is very small. 

Page 8, para. 5: Will the food base and trout assessments test the hypothesis relating to algae 

response from “cropping”? 

Response: as with other projects in this high flow science plan, we will be integrating these 

results with the results of other projects. In this case, we will not only be sampling the food base 

in conjunction with the high flow experiment, but will continue our ongoing aquatic food base 

project that includes monthly sampling in the Lees Ferry reach (and at Diamond Creek) and 

quarterly, full river trip sampling throughout Grand Canyon. We expect that this work will 

address the reviewer’s question. 

Re: rainbow trout (RBT) 

Response: our project 4.B. is directed at investigating the fate of young rainbow trout during and 

after the high flow event. It is a pilot study because we are investigating whether the equipment, 

sonic tags, will allow us to monitor individual fish in such conditions. Learning more about this 

species at this life stage helps us evaluate whether these fish resist or return following high 

flows, or do they move downstream. We also intend this project to help us investigate whether 

these tags may be used in native fishes in the future to help track their individual movements. 

COMMENTS SPECIFIC TO 1C: 
In light of concerns raised in the latest SA review, some additional information and clarification 

about the issues that were perceived as being problematic in the plan, particularly as they pertain 

to socio-cultural elements of Project 1C, are provided below: 

General Response 

GCMRC was directed to develop a science plan to guide the research that would take place if a 

high flow experiment were to occur in FY08. In keeping with the emphasis of the Long Term 

Experimental Plan, we were also directed to focus the experimental design around sediment 

dynamics and fish responses. While it is fully recognized that the concerns of the AMP are 

much broader than just sediment and fish, current priority concerns constrained the scope of our 

science plan primarily to these two key resource areas, with the understanding that by focusing 

on these key elements, we would still be able to learn more about how high flows affect other 

resources, including recreational camping beaches and archaeological sites. 

In order to meet these objectives, and also to promote integration of science activities, we 

designed Project 1 (A-D) to focus on sediment research primarily, but with supplementary 

research to link the sediment studies to other related resource concerns. One part of Project 1C 

(a relatively minor part) includes work designed to further our understanding of how changes in 

sediment stored in sand bars affects camping areas and cultural resources. Because sociocultural resource concerns are identified in the project description, many previous readers of the 

science plan misconstrued 1C to be a "cultural project." We tried to address this 

misunderstanding in our revision of the plan, but apparently we were less than fully successful in 

doing so, because it is seems from the way in which this project is characterized in the review, 

some misunderstanding persists. 

The SA review states "This study proposes to examine how high flows from the GCD and 

"normal" releases will: 1) contribute to--or subtract from—the amount of sediment on sand 

bars, especially “campable” ones; and 2) determine whether or not aeolian sands will be moved 

by canyon winds up and over archaeological sites to protect them from the tourists and possibly 

fill in the erosion gullies currently decimating many of the sites. “ This is partially correct, but it 

misses the main intent of 1C. In fact, the primary focus of 1C is to compare the 2008 eddy 

sandbar responses to previous measurements taken of the same features during and following the 

1996 and 2004 high flow experiments. This will be accomplished by conducting total station 

surveys and collecting underwater sonar measurements and grain size data from a sample of sand 

bars that NAU geologists have been monitoring for the past 17 years. Secondary objectives of 

1C are to learn more about how the creation and persistence of sand bars deposited by an HFE 

affect other sediment-dependent resources such as campsites, cultural sites, and backwaters, but 

the bulk of the effort and funding in Project 1C is dedicated to gathering measurements from the 

eddies and sand bars, not socio-cultural sites. 

The design of the sand storage study and its primary focus on sand bar measurements imposed a 

lot of constraints on the socio-cultural elements of this project. Fortunately for the socio-cultural 

program, about 3/4 of the sand bars to be studied by NAU as part of the HFE experiment are also 

used as recreational campsites, so at these locations, we will be able to measure campable area in 

addition to sand bar area and volume. There is however, considerably less concordance between 
the NAU sand bar sites and archaeological resources, particularly in terms of archaeological sites 

with prior high flow data. While it might have been preferable (for many reasons) to design an 

entirely separate cultural resources study--one that perhaps took an entirely different, systemic 

approach to evaluating the role of high flow events on cultural resources--many factors 

prevented us from doing this, including: 1) departmental direction to focus the science plan 

primarily on sediment and fish; 2) funding constraints; 3) the nature of existing monitoring data 

and the scope of current monitoring activities for cultural resources; and 4) continuing 

controversy within the GCDAMP about the area of potential affect from dam operations, and 

consequently, ongoing lack of agreement among the various program stakeholders as to the 

appropriate scope of cultural studies in general. Furthermore, an important stated objective for 

this high flow experiment is to evaluate the responses of resources in comparison to responses 

measured during previous high flow tests. The limited amount and variable quality of cultural 

resource-related data collected during previous high flow experiments constrained our options 

for making comparisons of this nature, but we still felt it was important and worthwhile to 

attempt to do so. Therefore, we decided to focus most cultural resource-related research around 

the archaeological sites where we have pre-existing, well documented, quantified measurements 

to serve as a basis of comparison. 

With this general background in mind, responses to some of the more specific questions that 

were raised in the SA review are provided below: 

It would be nice to see more details on some of the new efforts in 1C in particular, such as 

exactly how they plan to measure aeolian transport, how long monitoring will continue after 

the BHBF, and details of the spatial sampling (number of gullies, resolution of surveys). 

Response: We admit that the science plan is short on details. In fact, early versions of the plan 

included considerably more detail about the cultural components of Project 1C, but this created 

an awkward and unbalanced document because only cultural elements of Project 1C were 

discussed in detail while most of the other project elements simply referenced previously 

published studies. In the end, the managers and editors of the science plan decided to forego 

including details about methods and rationales and just reference previously published studies 

where these details were already described. In subsequent revisions to the plan, we removed 

additional text relating to the cultural resources portion of 1C in an attempt to balance the 

presentation and fix misconceptions about the primary focus of Project 1C. 

As previously noted, the cultural program is not positioned to evaluate the responses of cultural 

resources on a systemwide basis. We are currently awaiting the results of a geomorphic 

assessment that characterizes the geomorphologic settings and processes affecting individual 

sites and are working with another branch of USGS to refine a HEC-RAS model that will in the 

future allow us to project flow elevations in relation to archaeological sites, but neither of these 

tools were available for use in designing this experiment. We also lack the requisite data that 

would be needed to model aeolian transport potential at individual sites on a systemwide basis. 

What we are positioned to do through this experiment is evaluate the responses of individual 

archaeological sites to an HFE event and compare the responses to those documented during 

previous HFEs. The purpose in doing this is to determine whether previously measured 
responses are replicable and to monitor the potential persistence of those responses following the 

HFE. 

The proposed cultural research is focused at archaeological sites where studies were conducted 

in conjunction with the 1996 and 2004 experimental high flows and for which we have preexisting weather data, aeolian transport data, and arroyo survey data, to provide a basis for 

comparison to the results of this next high flow test. Several of these sites are also being 

monitored as part of the Cultural Monitoring R&D effort that started in 2006, so we will have a 

fair amount of previously collected monitoring and research data with which to evaluate the 

outcomes of a 2008 HFE. These sites were originally selected (for previous study by other 

researchers) because they were located where the interaction between cultural resources, 

geomorphic processes of interest (gully erosion, aeolian deposition), and effects from a high flow 

experiment potentially could be measured. Therefore, although the data gathered from these 

sites will be very useful for comparing the outcomes of the 2008 experiment to those of previous 

experiments, they are not suitable for characterizing the response of cultural sites systemwide. 

To provide some balance to our interpretation of results, we will also be comparing the responses 

observed and measured at previously studied sites with those from other cultural sites that were 

not studied in past experiments but are currently included in the cultural R&D project. Some of 

the latter sites are located more than a 1⁄4 mile from the river, so we will have sites in a variety of 

geomorphic settings with which to evaluate responses to an HFE test. Obviously, if a primary 

goal of this proposed experiment had been to characterize systemwide responses of cultural 

resources to an HFE, a different approach (and much more funding) would have been required; 

however, for reasons already mentioned, measuring systemwide responses of cultural resources 

is not a primary focus of the proposed HFE. 

 

One of the goals of 1D is to determine where backwater habitats will develop, but isn’t that 

really part of the goals of 1-B and 1-C? 

 Response: 1B specifically focuses on documenting how a few eddies in the Eminence area 

respond to changing sediment and flow conditions over the course of the HFE. This information 

is needed by sediment scientists to better understand and model the mechanisms and process of 

sand evacuation from and deposition in eddies during a high flow event. 1B does not look at 

where backwaters develop, but only at how. The backwater project component, 1D, was not 

incorporated in Project 1C because it represents an entirely new effort and approach. The 

primary focus of Project 1C is to repeat measurements made during previous high flows to 

enable comparison of response between the 2008 event and the earlier events. In response to 

concerns raised during earlier reviews of the experimental plan, Project 1D was designed to 

provide a system wide characterization of changes in backwater habitat to the 2008 high flow. 

The Abstract for the study admits . . . that the high flow experiments of 1996 and 2004 did 

little to “increase campable areas at sandbars on a more sustainable basis” (p. 26). The 

immediate question is, why might the next one produce a more positive outcome? 

Response: The question posed for campsites reflects the focus of the main strategic science 

question driving Project 1 and the GCMRC physical science program as a whole: “Is there a 

flow only operation that will rebuild and maintain sandbar habitats over decadal time scales?” 
We already know that we can increase campable area on a temporary basis by conducting a 

single high flow test – this has been demonstrated by the work of Kaplinksi and others with data 

collected around previous high flow events. Now we want to learn if this can be done on a 

sustainable basis by focusing more attention on the fate of the bars following the high flow test. 

The November 2004 test flow produced a positive sandbar response in the upper portion of the 

canyon, along with an increase in campable area, but the experiment was followed a month later 

by high fluctuating winter flows in January through March which rapidly eroded many newly 

formed bars. The 2005 winter high fluctuating flows were essentially a mitigation measure 

designed to generate power and possibly suppress rainbow trout reproduction; they were not 

considered to be an integral element of the experiment, and consequently, their effects on sand 

bars were not systematically monitored as part of the 2004 HFE. This time we will be 

monitoring the response of bars following the high flow event by taking daily photographs and 

periodic repeat measurements to improve our understanding of how dam operations following an 

HFE affect the newly formed bars over time. Ultimately, what the sediment scientists are trying 

to find out is whether it is possible to manage sediment in the system on a sustainable basis (and 

by extension, also sustain campable area) through implementing a combination of periodic high 

flow events under sediment enriched conditions in conjunction with carefully managed 

intervening operations. We propose to answer this question incrementally, using knowledge 

gained directly from this high flow experiment and through other means, such as modeling. 

The Abstract goes on to ask, “Do sandbars deposited by high-flow experiments contribute to 

the preservation of archaeological sites in the river corridor?” The answer, at least as 

observed by those on the June 2007 SA river trip, is that sandbars, however derived, do not 

appear to contribute to the preservation of sites. 

Response: Please review the reports produced by Draut and others (cited in the science plan and 

referenced at the end of this document) for more background information on the aeolian issue. 

The archaeological sites that the SAs visited in June were not chosen specifically to illustrate the 

role of aeolian processes as they affect archaeological site preservation in the river corridor; they 

were selected because they fit within the SA trip itinerary, did not require much time or effort to 

access, and allowed us to illustrate a diversity of issues that are relevant to understanding cultural 

resource concerns in the river corridor. Many (but by no means all) of the sites in the river 

corridor are built on or partially buried by sediment derived from the Colorado River and 

reworked by wind. In the past, high flow events periodically redeposited sand at higher 

elevations along the river, where the sediment was readily available for redistribution by wind. 

Now high flow events rarely occur, sand bars and Aeolian sand deposits are diminishing, and 

there is little opportunity for sand to be replaced at higher elevations once it is removed. IF the 

primary strategic science question for sediment can be answered and “a flow-only operation that 

will rebuild and maintain sandbar habitats over decadal time scales” can be identified through 

experimentation and modeling, then it is possible that degradation of archaeological sites could 

be slowed in some parts of the river corridor through periodically rebuilding high elevation sand 

bars and sustaining them long enough for wind to rework and redistribute the sediment over the 

sites. The knowledge gained from this experiment will contribute towards learning whether the 

AMP goal for cultural resources is attainable or not, but a single high flow test will certainly not 

resolve all the issues affecting cultural resource condition in the river corridor 
The big sites we saw at the Palisades area would require many cubic meters of aeolian sand to 

fill existing gullies that run directly through the sites and then remain there. 

Response: We agree. Portions of the Palisades area are now so severely eroded that there is 

little that can be done to change its degraded condition. This is one reason why one site in this 

area is now slated for data recovery in 2008-2009. The reason that arroyos and sand transport 

are being measured at this particular location as part of the current experiment is because several 

other sites in this area are not eroded to the same degree as the ones visited by the SAs, and these 

sites are currently being monitored as part of the cultural R&D effort, plus we have multiple 

years of previous data and measurements from this area, including detailed survey and aeolian 

transport measurements around the high flow events of 1996 and 2004, so it will be possible to 

directly compare effects of the proposed 2008 event with those of previous high flow tests (e.g., 

Yeatts 1996, 1998; Hazel and others, in review.) 

A relevant question is, assuming the sand did somehow get properly distributed, how would 

such loose deposits resist fast running water coming down through the existing gullies from 

cliffs and terraces above? The check dams previously built across the gullies at the Palisades 

sites were obviously of no avail. This is not sufficiently addressed in the study methods. 

Response: These specific questions fall outside the scope of the current HFE science plan. As 

discussed in the plan, research proposed in the HFE science plan is intended to supplement--not 

replace or duplicate--work already underway as part of the annual work plan. We are currently 

actively evaluating different monitoring protocols for evaluating how fast sediment is being 

removed from archaeological sites as part of the cultural R&D effort. USU researchers are also 

examining how weather events, check dams, and specific geomorphic attributes such as soil 

tensile strength and permeability affect rates of erosion, so these questions are being addressed 

through the annual research program. 

The part of the study relating to the cultural sites does not appear to be a legitimate scientific 

matter, at least as stated in Section 1.C. It is, rather, an ethical archaeological issue (Fowler1, 

Jolie and Salter 2008; Green 2008). 

Response: We are perplexed by this comment and require additional clarification in order to 

respond. While we have not had an opportunity to review the second referenced article, the first 

one discusses archaeological ethics in terms of diverse contexts such as national and 

international legal frameworks, knowledge making and professionalism, conservation of 

resources, trafficking in antiquities, relations with self-defined groups, and partisan politics. 

With the exception of antiquities trafficking, all of the above mentioned ethical contexts are 

 

1

 Fowler, D.D., E.A. Jolie and M.W. Salter. 2008 Archaeological Ethics in Context and Practice, In Handbook of 

Archaeological Theories, edited by R.A. Bentley, H. Maschner and C. Chippindale, pp.409-422. AltaMira Press, 

Lanham, Md. 

Green, T. J. 2008 Cultural Resource Management. In Handbook of Archaeological Theories, edited by R.A. Bentley, 

H. Maschner and C. Chippindale, pp.375-394. AltaMira Press, Lanham, Md. 
directly relevant to ongoing issues and concerns of the Glen Canyon Dam Adaptive Management 

Program. Nevertheless, it is unclear to GCMRC how the SAs’ comment was intended to apply 

to the high flow experiment science plan specifically. 

GCMRC is charged with conducting research and monitoring to help managers understand how 

dam-controlled flows--including experimental high flows--affect and potentially benefit natural, 

cultural, and recreational resources. Do the SA’s have information to indicate that this issue has 

been sufficiently studied already or that it is not a viable scientific issue worthy of investigation? 

Is the SAs’ ethical concern that insufficient effort and funding is being directed towards 

recovering information from actively eroding archaeological sites while research and costly 

experimentation continues to take place? This last concern is currently being addressed by the 

Bureau of Reclamation as an NHPA compliance issue through initiation of a multiyear, multimillion dollar archaeological excavation project. In light of the serious implications of this 

comment, we request that the SAs clarify its’ context and intended meaning in relation to the 

HFE science plan review. 

How specifically does, or might, aeolian sands get blown onto sites and what keeps them 

there? How, specifically, does, or might, aeolian sands get blown into erosion gullies across 

sites and what keeps them there? The questions are not meant to be facetious, but rather to 

say, “Provide us with more information.” As presently stated, the “experiment” does not read 

like a well designed inquiry into a difficult, possibly intractable, problem.

Response: As previously mentioned, the HFE science plan specifically describes additional 

research and monitoring activities that will be implemented in conjunction with a short-term high 

flow test. These activities are intended to supplement, but not duplicate or replace, monitoring 

and research activities identified in the FY08 annual work plan. HFE research and monitoring 

activities have been specifically designed to build upon and complement existing monitoring and 

research plans, not replicate them. Once again, we refer you to the previously mentioned 

publications by Draut and others for some of the answers to your questions (a list of reports is 

provided below) and to the cultural monitoring R&D proposal for more details on the 

development of a long-term approach for examining methodological and process issues that 

affect how we can track and evaluate various geomorphic processes and factors—including 

occasional high flow releases—that contribute to archaeological site preservation or degradation 

in the CRE. We request your patience while reports on the geomorphic field studies conducted 

over the past two years by USU and USGS researchers as part of the cultural R&D effort are 

completed. We expect reports on that work to be available later this spring and in early summer 

2008. 

COMMENTS SPECIFIC TO 1D: 

We are concerned by the lack of detail regarding the geomorphic aspects of 1D, the study of 

backwaters. 

Response: We have been increasing our staff to better address this project, and are now in the 

process of increasing the amount of detail regarding the geomorphic aspects of this study. 
[Study 1D] In paragraph 3 of this plan it states that highest densities of humpback chub occur 

in vegetated shorelines and only 5% or less are captured in backwaters. This indicates that 

some shorelines (perhaps eddies or shallow runs) are important for the fish. 

Response: on page 35 of the December 27, 2007 version of the plan, it states: “Protected 

backwater habitats are a relatively small portion (approximately 5% or less, depending on 

conditions and flows) of the nearshore habitat in the Colorado River in Marble and Grand 

Canyons.” The 5% reference is to the habitat, not fish captures. That said, we share the 

reviewer’s concern that other habitats need to be considered when evaluating relative value of 

different habitats, which is why we propose to develop an ecology of near shore habitats project 

that investigates native fish habitat use in a variety of habitats. 

We would like to see 1D(b) changed...to indicate: “why fish use them.” 

Response: We believe that the productivity and temperature data that we will collect will address 

this information need, at least indirectly. If backwaters offer a thermal refuge from the mainstem, 

have slower velocities (less energetically expensive than the mainstem), and offer more food 

items than the mainstem, we would infer that these advantages would serve as attractants to 

native fishes, as well as nonnatives. 

Study 1D is a good design, but why the emphasis solely on autochthonous production, 

particularly in backwaters? 

Response: We have previously made measurements of allochthonous production and inputs and 

have found it to be minimal. That said, we expect that both autochthonous and allochthonous 

production will be investigated in our proposed near shore ecology project. 

Table 4 (pg. 40) does not include a schedule for ecological measurements of chlorophyll, NPP, 

phytoplankton, or zooplankton. 

Response: We will be investigating the additional physical and biological parameters suggested 

during the 1D trips in February, March, May, and September. 

Comments on study 2. 

Response: These comments are very constructive and we will use them and the cited references 

to review our field protocol and to incorporate into the eventual reporting on this project. 

Project 1D (backwater study) 

The issues raised in the Science Advisor review of the High Flow Science Plan pertaining to 

project “1D” relate mainly to whether the project contains an adequate emphasis on geomorphic 

process and the degree of coordination and integration between the backwater study and other 

elements of the experimental plan. 
These concerns are valid and reflect the fact that backwaters have received much less research 

attention than many other aspects of the physical system in Grand Canyon and that this research 

is a new component of the experimental plan. This discussion will attempt to clarify the 

geomorphic components of the current backwater (project 1D) study plan. In the context of this 

discussion (and the 2008 High Flow Experimental Plan), we use the term backwater to refer to 

areas of stagnant flow or low velocity flow that occur in embayments separated from the main 

current by eddy-deposited sand bars (Schmidt and Graf, 1990; Rubin et al., 199?; Goeking et al., 

2003). 

The geomorphic component of the backwater project is designed to address the high flow science 

questions of (1) does the high flow create backwater habitat? And (2) do backwaters persist 

through Record of Decision flows that will occur following the high flow? Addressing these 

questions requires some emphasis on form and changes in form over detailed process 

measurements. The plan does, however, include some process measurements and also includes 

systematic geomorphic measurements that will be used to improve our understanding of the 

connection between backwater form and other channel morphologic characteristics. In 

summary, the plan includes (1) an inventory that will provide some measure of system-wide 

response to the high flow and following dam operations, (2) topographic/bathymetric surveys 

that will provide measurements of backwater form for a large number of study sites, and (3) 

measurements of topography/bathymetry and flow structure during the high flow experiment at 

three eddies under project 1B. 

Inventory Measurements 

Previous studies of backwaters (Goeking et al., 2003) and continuing investigation within 

GCMRC have indicated high spatial and temporal variability in backwater size and abundance. 

Goeking et al. (2003) identified from 0.5 to 3 backwaters per km in the 21 km they studied, 

implying a total population of at least 200, but possibly 1000 or more backwaters in Grand 

Canyon. There is, therefore, much concern that detailed measurements made at a few sites will 

not be representative of system-wide response. While a system wide inventory of backwaters 

could be conducted with pre- and post-high flow aerial imagery, such imagery will not be 

conducted for the 2008 experiment. Therefore, one component of the experimental plan includes 

an inventory of all backwaters before and after the experimental flow. 

The inventory measurements will be made on the six trips identified as the “tape and level” 

measurements in Table 4 of the Science Plan. Every sandbar-controlled backwater will be 

visited during these trips and measurements will be made of backwater area and volume at the 

discharge of observation and the daily high flow based on evidence of the high stage. Backwater 

relief will also be measured as the elevation of the backwater trough relative to the adjacent 

sandbar crest. 

Surveys 

Approximately 60 to 80 individual backwaters will be selected as detailed study sites for 

topography/bathymetric surveys of the backwater and adjacent sand bar. These surveys will 

initially be referenced to local control points and will eventually be referenced to the GCMRC 

control network. Using measurements of water surface and high water marks, local stage-
discharge relations will be developed at each study site. The topographic information from each 

survey and the stage-discharge relations will be used to determine relations for backwater area 

and volume as functions of discharge. This will enable calculation of backwater area and 

volume for discharges other than those observed in the field. It will also be possible to determine 

which of the studied backwaters are present only over a narrow range of flows and which persist 

over a broad range of flows including the upper range of Record of Decision flows. We also 

anticipate that building a database of backwater geomorphic information will help to identify 

connections between channel characteristics and backwater characteristics. Surveys of 

backwaters at sites that are included in the long-term sandbar monitoring studies will be made as 

part of project 1C. Approximately 60 additional backwaters will be surveyed in project 1D. 

Although the measurements made in project 1C will include bathymetry and topography over a 

larger area, both will include comparable data collection for the backwater and adjacent sandbar 

crest. 

Process Measurements – connections with project 1B 

Project 1B includes detailed measurements of topography and/or bathymetry and flow structure 

at up to three eddies during the high flow. Although the connection between this effort to 

increase our understanding of the processes of sandbar formation and the processes of backwater 

formation was not articulated in the Science Plan, it is clear that understanding of the processes 

of backwater creation first require understanding of the processes that lead to the formation of 

sand bars in eddies. Importantly, each of the eddies selected for study in project 1B contains a 

backwater and monitoring changes to the backwaters is an additional focus of this work and part 

of the motivation for that project component. 

REFERENCES: 

1

 Fowler, D.D., E.A. Jolie and M.W. Salter. 2008 Archaeological Ethics in Context and Practice, In Handbook of 

Archaeological Theories, edited by R.A. Bentley, H. Maschner and C. Chippindale, pp.409-422. AltaMira Press, 

Lanham, Md. 

Green, T. J. 2008 Cultural Resource Management. In Handbook of Archaeological Theories, edited by R.A. Bentley, 

H. Maschner and C. Chippindale, pp.375-394. AltaMira Press, Lanham, Md. 

Yeatts, M., 1996, High elevation sand deposition and retention from the 1996 spike flow: an assessment 

for cultural resources stabilization: Unpublished report on file at the Grand Canyon Monitoring and 

Research Center, Flagstaff, AZ., 32 p. 

Yeatts, M., 1998, High elevation sand retention following the 1996 spike: Unpublished report on file at 

the Grand Canyon Monitoring and Research Center, Flagstaff, AZ., 15 p.

Existing Publications from the 2003-2006 Aeolian Project: 

Draut, A.E., and Rubin, D.M., 2007, The role of aeolian sediment in the preservation of 

archaeological sites in the Colorado River corridor, Grand Canyon, Arizona-Final report on 

research activities, 2003-2006: U.S. Geological Survey Open-File Report 2007-1001, 

http://pubs.usgs.gov/of/2007/1001/ 
Draut, A.E., and Rubin, D.M., 2006, Measurements of wind, aeolian sand transport, and 

precipitation in the Colorado River corridor, Grand Canyon, Arizona-January 2005 to January 

2006: U.S. Geological Survey Open-File Report 2006-1188, 88 pages, 

http://pubs.usgs.gov/of/2006/1188/ 

Draut, A.E., and Rubin, D.M., 2005, Measurements of wind, aeolian sand transport, and 

precipitation in the Colorado River corridor, Grand Canyon, Arizona-November 2003 to 

December 2004: U.S. Geological Survey Open-File Report 2005-1309, 70 pages, 

http://pubs.usgs.gov/of/2005/1309/ 

Draut, A.E., Rubin, D.M., Dierker, J.L., Fairley, H.C., Griffiths, R.E., Hazel, J.E. Jr., Hunter, 

R.E., Kohl, K., Leap, L.M., Nials, F.L., Topping, D.J., and Yeatts, M, 2005, Sedimentology and 

stratigraphy of the Palisades, Lower Comanche, and Arroyo Grande areas of the Colorado River 

corridor, Grand Canyon, Arizona: U.S. Geological Survey Scientific Investigations Report 2005-

5072, 68 pages, http://pubs.usgs.gov/sir/2005/5072/ 

Publications relevant to the HFE currently in press or undergoing peer review: 

Draut, A.E., and Rubin, D.M., The role of aeolian sediment in the preservation of archaeological 

sites in the Colorado River corridor, Grand Canyon, Arizona: U.S. Geological Survey 

Professional Paper, in press. 

Draut, A.E., and Rubin, D.M., The role of aeolian sediment in the preservation of archaeological 

sites, Colorado River corridor, Grand Canyon, Arizona, in Van Riper, C., and Sogge, M., (eds.), 

Integrating science and management on the Colorado Plateau: University of Arizona Press, in 

press. 

Draut, A.E., Rubin, D.M., Dierker, J.L., Fairley, H.C., Griffiths, R.E., Hazel, J.E. Jr., Hunter, 

R.E., Kohl, K., Leap, L.M., Nials, F.L., Topping, D.J., and Yeatts, M., Application of 

sedimentary-structure interpretation to geoarchaeological studies in the Colorado River corridor, 

Grand Canyon, Arizona, USA: Geomorphology, in press. 

Hazel, J.E., Kaplinski, M., Parnell, R., and Fairley, H.C., Effects of the November 2004 High 

Flow Experiment on the Arroyo Network near Palisades Creek along the Colorado River in 

Grand Canyon National Park, Arizona. U.S. Geological Survey Open File Report, in review. 

Kaplinski, M., Hazel, J.E., Parnell, R., and Fairley, H.C., Campsite Area Monitoring in the 

Colorado River Ecosystem from 1998 to 2006. U.S. Geological Survey Open File Report, in 

review.