United States Department of the Interior 

U.S. GEOLOGICAL SURVEY

SOUTHWEST BIOLOGICAL SCIENCE CENTER

GRAND CANYON MONITORING AND RESEARCH CENTER

2255 NORTH GEMINI DRIVE, MS-9394 

FLAGSTAFF, ARIZONA 86001

928 556-7094 Telephone

928 556-7092 Fax

October 18, 2006 

MEMORANDUM 

To: Technical Workgroup Members, Science Advisors and GCMRC’s cooperating 

physical scientists who participated in the August PEP review meeting

From: Ted S. Melis, Deputy Chief

Subject: Distribution of External Peer Review on Sediment Monitoring Protocols

Attached, is the SEDS-PEP III panel’s final report on 2000 through 2006 research and 

development results on long-term monitoring of sediment resources of the Colorado River 

ecosystem. 

Again, I would like to take this opportunity to thank those of you who participated in the August 

15-17, 2006 meeting in Flagstaff. I especially appreciate the fact that the review panel delivered 

the report three weeks ahead of the assigned October 31st due date. 

I believe that this review is another milestone for the GCMRC’s science program and provides 

many solid recommendations that should be carefully considered and discussed by the Technical 

Workgroup and the GCMRC staff as future science planning continues. 

Please feel free to contact me at 928-556-7282, if you have questions regarding this report. 
2

GRAND CANYON MONITORING 

AND RESEARCH CENTER 

Protocols Evaluation Program (PEP-SEDS III) 

Final Report of the Physical Resources Monitoring Peer Review 

Panel 

October 6, 2006 

U.S. Geological Survey Field Center 

Flagstaff, AZ 
3

PROCEEDINGS OF THE EXTERNAL PEER REVIEW WORKSHOP III ON LONGTERM MONITORING OF WATER AND SEDIMENT RESOURCES OF THE 

COLORADO RIVER ECOSYSTEM 

WORKSHOP-III DATES: August 15-17, 2006

MEETING LOCATION: USGS Field Center, Bldg. #3, 2255 N. Gemini Dr., Flagstaff, AZ 

PHYSICAL SCIENCE PEER REVIEW PANEL: 

 CHAIR: Ellen Wohl, Department of Geosciences, Colorado State University, Ft. 

Collins, CO, 80523-1482, phone 970-491-5298, fax 970-491-6307, 

ellenw@warnercnr.colostate.edu

James P. Bennett, U.S. Geological Survey (retired), 3026 Parfet Drive, Lakewood, CO, 

80215, merjimeric@comcast.net 

Michael D. Blum, Department of Geology and Geophysics, E235 Howe-Russell, 

Geosciences Complex, Louisiana State University, Baton Rouge, LA, 70803, phone 225-578-

5735, fax 225-578-2302, mike@geol.lsu.edu 

Gordon E. Grant, USDA Forest Service, Pacific Northwest Research Station, Forestry 

Sciences Laboratory 280, 3200 SW Jefferson Way, Corvallis, OR, 97331-8550, phone 541-750-

7328, fax 541-750-7329, Gordon.grant@orst.edu 

Daniel M. Hanes, U.S. Geological Survey, Coastal and Marine Geology Program, 

Pacific Science Center, 400 Natural Bridges Drive, Santa Cruz, CA, 95060, phone 831-427-

4718, fax 831-427-4748, dhanes@usgs.gov 

Alan D. Howard, Department of Environmental Sciences, University of Virginia, 291 

McCormick Road, P.O. Box 400123, Charlottesville, VA, 22904-4123, phone 434-924-0563, fax 

434-982-2137, ah6p@virginia.edu 

David S. Mueller, U.S. Geological Survey, Office of Surface Water, 9818 Bluegrass 

Parkway, Louisville, KY, 40299, phone 502-493-1935, fax 502-493-1909, dmueller@usgs.gov 

David H. Schoellhamer, U.S. Geological Survey, Placer Hall, 6000 J Street, 

Sacramento, CA, 95819-6129, phone 916-278-3126, fax 916-278-3071, dschoell@usgs.gov 

Francisco J. Simoes, U.S. Geological Survey, Denver Federal Center, National Research 

Program, Box 25046, Lakewood, CO, 80225-0046, phone 303-236-4556, fax 303-236-5034, 

fsimoes@usgs.gov 
4

I. OVERVIEW

 The Grand Canyon of the Colorado River is one of the nation’s premier national parks 

and one of the most visited natural sites on Earth. As the centerpiece of a heavily visited 

landscape, the riverine corridor attracts attention from diverse stakeholders that include 

numerous government agencies, user groups, scientists, and the general public. Management of 

natural resources and human activities within the Colorado River ecosystem is likely to remain 

the focus of intense scrutiny by these diverse stakeholders for decades to come. 

Increasing concern over human effects on the Colorado River ecosystem led to the 

establishment of the Glen Canyon Environmental Studies (GCES) Program in 1982, which 

eventually gave rise to the present Glen Canyon Dam Adaptive Management Program (AMP). 

This latter program includes the Grand Canyon Monitoring and Research Center (GCMRC) as 

its science component. The Protocols Evaluation Panel convened in Flagstaff during August 

2006, and is part of ongoing peer review of monitoring and research efforts carried out by the 

GCMRC. The August 2006 panel forms the third such review carried out by the Physical 

Resources Program thus far (earlier panels were convened in 1998 and 1999). The panel was 

charged with evaluating current recommendations on research and long-term monitoring of 

physical resources below Glen Canyon Dam, and was asked to respond to six review elements 

focused on monitoring protocols (Appendix 1) based on the Strategic Science Questions 

developed at the Knowledge Assessment Workshops in 2005 (Appendix 2). This report 

summarizes the recommendations of the panel with respect to the six review elements and to 

broader issues that the panel considers vital to the success of the GCMRC in administering a 

program of physical resources monitoring and research. 

Design of the monitoring program 

 As has been the case during previous peer reviews, the 2006 panel is generally impressed 

with the direction of the GCMRC physical resources monitoring program as it is presently 

designed and operated. Largely as a result of research and monitoring guided and facilitated by 

the GCMRC, our collective understanding of the Colorado River ecosystem is remarkably 

detailed and comprehensive. The results of decades of study on the Colorado River ecosystem 

represent a unique and exemplary knowledge to guide river management and restoration on the 

Colorado and other rivers. The panel commends the individual scientists and the program 

administrators on the degree of communication and collaboration among research teams. 

Biennial science symposia attended by all participating scientists undoubtedly foster this 

communication and collaboration, but these symposia would be insufficient if individual 

scientists did not make the effort to work closely together that is reflected in group efforts such 

as FIST (Fine-grained Integrated Sediment Team) or the collaboration between David Topping 

and David Rubin. 

Further efforts are necessary, however, to more fully integrate core monitoring and 

research efforts. The coarse sediment monitoring (Webb and others) seems to be better 
5

integrated with experiments and field work than the fine sediment modeling (Wiele and others), 

for example, but the projects focused on coarse sediment and fine sediment are not well 

integrated. Similarly, the scientists engaged primarily in modeling efforts could make more rapid 

progress in model development and application to specific management needs if these scientists 

worked more closely with the research teams focusing primarily on collection and analysis of 

field data. The clear articulation of a guiding framework that serves as a reference point for the 

role of individual studies and for integration of individual studies would strengthen 

collaborations among project scientists, facilitate effective communication between the three 

core monitoring programs of the GCMRC, and enhance the ability of outside reviewers to 

comment on the physical resources program. 

 The panel commends the attention given by participating scientists to the management 

implications of their monitoring and research activities. Numerous examples of using specific 

research results to inform management decisions were provided during the presentations given 

by participating scientists as part of the August 2006 meeting. Peter Wilcock, for example, 

discussed the potential to use the fine sediment model to understand the effect of daily flow 

fluctuations on sand retention following sand inputs from the Paria River, and David Topping 

noted that variability in some aspects of the flow regime post-dam exceeds pre-dam variability, 

which has implications for the height and frequency of fluvial re-working of terrace deposits and 

the erosion or protection of archeological sites. It is critical to the adaptive management process 

and to comprehensive, ecosystem-scale modeling that this consideration of management 

implications continues during design and implementation of future monitoring activities. 

 The panel also commends the program director and individual scientists for the progress 

made in addressing monitoring and research needs identified by the previous review panel 

during the 1999 meeting. This level of responsiveness helps to move the program toward 

meeting the needs of adaptive management, and gives the program a level of credibility that 

keeps participating scientists and stakeholders positively engaged in the adaptive management 

process. 

 At the broadest level, the effectiveness of the GCMRC to inform and promote adaptive 

management could be further improved by better integration among the three core monitoring 

and research programs of physical resources, biological resources, and sociocultural resources. 

Such integration is best achieved from bottom-up collaborations of scientists rather than topdown management edicts. Formulation of scientific questions and studies that bridge the three 

programs is one way to accomplish this. The programs appear to be starting such formulations, 

and the panel encourages continuation and expansion of these collaborations. 

The current adaptive management process, in which AMWG (Adaptive Management 

Work Group) and TWG (Technical Work Group) prioritize core monitoring information needs 

based on group consensus, is cumbersome and likely inhibits setting clear, prioritized goals and 

making decisions. Jacobson defines adaptive management as “a cyclic, learning-oriented 

approach to the management of complex environmental systems that are characterized by high 

levels of uncertainty about system processes and the potential ecological, social and economic 
6

impacts of different management options. As a generic approach, adaptive management is 

characterized by management that monitors the results of policies and/or management actions, 

and integrates this new learning, adapting policy and management actions as necessary.” 

Advances in understanding and improvements in management require that the adaptive 

management concept be better implemented. The gap between experimental floods, for 

example, should be less than eight years. Under the current adaptive management process, the 

identification of goals and approaches by AMWG and TWG takes the form of lists of priorities 

and needs considered mostly in isolation from each other and lacks a strong rationale for 

prioritization. 

II. SPECIFIC CHARGES TO THE PHYSICAL RESOURCES MONITORING PEER 

REVIEW PANEL (Appendix 1) 

Draft statements of work for FY 2007 

1. Integrated quality-of-water core monitoring, with emphasis on sediment elements 

(Topping and others). 

The panel considers the sediment statement of work (SOW) to be reasonable. 

This SOW effectively documents the role that the measurements play in overall sediment and 

water quality monitoring and in supplying data for modeling efforts. It is clear that most of the 

measurements and budgeted effort are related to background measurements and would be 

relatively unaffected by the occurrence (or not) of an experimental flow. The proposed activities 

seem to be important to creating a realistic sediment budget and water-quality assessment. The 

panel supports funding to continue the work by David Topping and others, and recommends that 

Topping be fully funded. Other staffing requests in the SOW are appropriate. 

The statement of work gives more attention to what has already been done than to 

proposed work for 2007, with the exception of installing a LISST infinity at the Paria River 

gage. Specific suggestions from the panel include 

• Greater attention to prioritization of proposed activities and associated budgeted 

items. 

• The SOW does not identify what fraction of the budget is support for any 

experimental flows that might occur during the budget period. Does the budget 

reflect the anticipation of an experimental flow, or would supplementary funds be 

required for such an event? 

• The level of effort and analysis provided seems to warrant a full-time effort by the 

project chief, rather than 75% of his time. 

• The scope and sophistication of sediment and water quality measurements have 

undergone dramatic increase during the past 3-5 years. Although the document 

clearly identifies the techniques, protocols, and schedules to be used, there is less 

sense of the place of the work plan in the long-term evolution of sediment and 

water quality monitoring. For example, which of the activities are baseline 

monitoring that would be expected to occur many years into the future, and which 
7

are relatively short-term measurements primarily to be used for model calibration 

and then discontinued? 

• The monitoring could be strengthened in two ways to reflect the scientific 

findings of the past few years. Two important discoveries are that bed sediment 

size and tributary (mainly Paria) sediment inputs exert first-order control on 

sediment transport in the Colorado downstream of Glen Canyon Dam. In light of 

this, the panel recommends more focus on 1) bed sediment grain size (and its 

temporal and spatial variations) and 2) Paria inputs. For grain size, we 

recommend that the bed sediment camera be added as a routine component of the 

monitoring during field trips. Some effort should be expended to explore the 

feasibility of a remotely operating bed sediment camera that could be used for 

"continuous" monitoring. With regard to the Paria river, a variety of sensors 

should be installed upstream of the Colorado River junction in order to obtain 

more accurate measurements of discharge, stage, suspended sediment flux, bed 

sediment grain size, and bedload sediment flux. The proposed LISST-infinity is a 

great start, but there should be even more emphasis on obtaining better data in the 

Paria, in order to more accurately constrain the sediment input to the 

Colorado. This is a significant request that requires either increased resources or 

cuts elsewhere. If program cuts are required, the panel recommends reducing 

work downstream of the Grand Canyon gage. 

• Instrumentation issues: A USGS series report thoroughly documenting instrument 

calibration and development of time series of cross-sectionally averaged velocity 

weighted suspended sediment concentrations (silt/clay and sand) should be 

written. A comparison of the D-77 bag sampler used on this project with the 

currently recommended D-96 sampler should be provided to document that the 

project sampler is acceptable. The review panel understands the difficulty and 

limitations of the D-96 sampler, but the performance of the D-77 bag sampler 

needs to be documented through direct comparison or standard isokinetic 

laboratory tests. A comparison of pumped and sampler collected water samples 

should be provided to document that pumping samples is acceptable. Suspendedsediment load is determined with the Equal Width Increment (EWI) method using 

five stations in a cross section, whereas the rule of thumb is twenty stations. An 

evaluation of whether the EWI method with five stations is sufficient should be 

provided. A subset of this report should be published in the peer reviewed 

literature. If possible, validation should also be presented. 

• The project should consider the cost of maintaining redundant systems as 

calibration and intercomparisons of data measurement techniques become 

sufficient. The LISSTs appear to be the instrument that requires the most 

maintenance and with fully operational acoustics could be considered for 

elimination to reduce long-term maintenance costs. If the data provided by the 

LISST continue to be important, the project should consider the LISST infinity 

which, although having a larger initial cost, will likely reduce long-term 

maintenance 
8

• The project should evaluate servicing frequency because several instrument 

malfunctions developed during the preceding six-month servicing interval, 

necessitating difficult and inefficient return trips by foot. Perhaps a four-month 

servicing interval would actually save the project money and allow for more 

efficient use of staff time. 

• When instruments are not operating, the shifting rating curves presented by Scott 

Wright appear to be a potential method to fill data gaps, and the project should 

continue to investigate this method. It is important that these data be appropriately 

flagged in the database, however, as being estimated. 

• Does the proposed SOW include funding to WRD to maintain and develop the 

water discharge side of the data? 

• Although Topping’s approach to characterizing the tributaries is the least 

expensive approach available, the accuracy of the siphon samplers is uncertain. 

• The techniques developed and used in the Grand Canyon to monitor suspended 

sediments should be fully developed and tested in other environments. The 

validation of these methods in other environments will provide added validation 

to the data collected in the Grand Canyon and will likely make these methods 

standard techniques rather than special, research-oriented techniques. This could 

be important in any court challenges to the scientific data produced. 

• The management information needs are for monthly data, but continuous data are 

still needed because of the ephemeral nature of flows, especially from tributaries, 

and the daily variation of discharge. 

• Data reports: Given that the water-quality data collection is evolving from a 

research activity to a monitoring activity, an annual USGS open-file report 

summarizing suspended-sediment concentration data should be written or the data 

should be included in Arizona’s Annual Data Report. 

• Error estimates: The project personnel are commended for their recognition and 

concern for the errors associated with the field measurements and the effects on 

long-term system response and prediction. The error analysis reported to the 

panel, however, was based purely on a composite unsigned error. The project 

should better determine the components of the error associated with random 

uncertainty and bias. It is recommended that someone with statistical expertise in 

quantifying long-term errors be consulted, and that a better representation of the 

prediction errors be determined. 

2. Modeling support linked to integrated quality-of-water core monitoring (Wright and 

others). 

The goals of the modeling effort, as outlined in the statement of work, are 

appropriate and reasonable. The statement of work appears to place the modeling effort 
9

within GCMRC, which the panel endorses. The proposed effort appears reasonable and very 

dependent on Scott Wright’s involvement. He has been working on the project for over two 

years, is knowledgeable of the system, appears to work well with other team members, and 

has the necessary sediment transport and modeling background. Although he recently moved 

to Sacramento, GCMRC should endeavor to maintain his involvement in the modeling effort. 

Steps should be taken to ensure that the modeling program is properly integrated with the 

core monitoring program of Topping and others. Where appropriate and possible these two 

programs should benefit from mutual feedback, because they share similar objectives. 

Participation of Scott Wright in both programs is regarded as a positive step in this direction. 

Additional specific comments from the panel (see Appendix 3 for written suggestions or 

recommendations provided by scientists): 

• The statement that the model will be used to fill data gaps where instrument problems 

have occurred must be implemented carefully. Model simulations are not observed data 

and need to be clearly identified and represented as simulations. 

• The 1-d temperature model seems appropriate, but the combination of separate 

FORTRAN codes that must be operated in sequence is awkward. Hopefully the interface 

will automate and hide all of this from the operational user. 

• Although the integration of tributary sediment input into the Colorado River sediment 

transport model is important, the panel is not convinced that the Colorado River model is 

currently adequate. Also, the budget for the proposed integration seems low, irrespective 

of the adequacy of the mainstem model. 

• It is unfortunate that the proposal does not address improvements to the current mainstem 

model. Presentations during the PEP by Peter Wilcock clearly showed the type of longterm results desired from the model, but the model is not currently capable of producing 

those results. The only task in the current proposal for addressing this deficiency is 

further investigation of beta. Given that the model did not accurately replicate the erosion 

of sand from eddies, more research is needed to parameterize the eddy contributions to 

sediment management in the model. 

• A long-term sediment transport model is desperately needed to demonstrate to 

stakeholders the potential results of various operational scenarios. This capability 

unfortunately does not exist at present, and the proposed work does not convincingly 

demonstrate that the current situation will be significantly improved. There was 

insufficient time to get into the detailed problems associated with the current model 

during the PEP, but the panel remains concerned about the condition of the model. The 

panel recommends that the current one-dimensional Colorado River model be critically 

reviewed by a small group that will be tasked with making recommendations to guide 

further development or re-development of the model. 

• No detailed statements of work corresponding to that provided for the Topping et al. 

effort detail the efforts of Rubin and Wright. 

• Although the document covers the new near-shore temperature monitoring (and 

modeling?) effort, it is not clear who will be responsible for this program. 

• The largest single line item in the budget is “Outside USGS Contract Science Labor 

(17% Burden Rate)” at $325K, but the dispersal of these funds is largely unexplained. 
10

Does this cover the beach monitoring activities of the NAU group and/or the coarse 

sediment monitoring and research efforts or river trip logistics? 

Effectiveness of current or proposed sediment core monitoring in meeting identified core 

information needs and answering strategic science questions 

Need for a comprehensive structured approach. At the most fundamental level, the panel 

notes the lack of a comprehensive structured approach that can be used to prioritize information 

needs, to define the flow of information that will get program scientists to a desired endpoint of 

understanding, and to specify the level of detail, such as the spatial and temporal resolution 

needed to address driving questions. It was not clear during the review panel meeting whether an 

integrative adaptive management model remains an envisioned endpoint of the GCMRC 

activities, because such a model was not used as a framework to guide discussion of physical 

science research projects. 

 As an example of the questions that arise in the absence of a structured approach, the 

panel remains uncertain how the efforts to model fine sediment dynamics (Steve Wiele and 

others) integrate with the efforts to model coarse sediment dynamics (Robert Webb and others). 

A structured approach defining how the different research components within the physical 

resources program fit together would promote understanding of program activities by peer 

reviewers and stakeholders, and would facilitate integration among individual scientists and 

research efforts. At present, such an understanding seems to be implicit in the minds of many 

individual researchers, but not clearly articulated in a framework on which all program scientists 

agree. A comprehensive structured approach would improve program effectiveness by allowing 

(i) identification of gaps in existing monitoring and research efforts, (ii) identification of gaps in 

the current state-of-the-knowledge of the overall system, (iii) evaluation of whether the balance 

among the effort distribution in monitoring, applied studies, and modeling is appropriate, (iv) 

evaluation of the cost versus benefit for specific lines of research (all of the existing studies 

represent good work, but it remains unclear whether extending some of the projects is beneficial 

to achieving long-term goals; the sediment mass balance, for example, is fairly mature at this 

point, whereas the fine sediment modeling is fairly immature), and (v) clear identification of, and 

agreement on, the integrated goals and objectives of the physical resources program. A 

structured approach would also provide a framework for integration of the physical program with 

the biological and cultural programs and for the adaptive management cycle of experimentation, 

monitoring, evaluation, and implementation. 

Fine sediment modeling. The panel believes that more effective communication is 

required between scientists involved primarily in modeling (Steve Wiele and others) and 

scientists focusing on data collection and analysis. Modeling must be a component of the mass 

balance, FIST, and coarse sediment projects, rather than a stand-alone exercise. This relationship 

requires that individual scientists work to ensure that they are making the best possible use of the 

data and understanding of other GCMRC scientists. The current collaboration between David 

Topping and David Rubin provides a good example of an effective partnership, whereas the 
11

apparent lack of collaboration between David Topping and Steve Wiele reduces the effectiveness 

of the GCMRC physical resources program. 

Scientists engaged in data collection and analysis should help guide model development 

by prioritizing the critical questions to be addressed in simulations, as well as identifying the 

appropriate spatial and temporal scope and resolution. A longitudinal, system-wide model of 

water and sediment movement within the river ecosystem is essential, for example, but this can 

only be developed if Wiele’s group puts forth an effort comparable to Topping’s group, and is 

more integrated into the physical resources program than at present. The panel feels that the 

development of the fine sediment model thus far is below what could reasonably be expected. 

Modelers need to better assess the most important aspects of model unknowns and pursue these 

systematically. The existing model could also be substantially improved by strengthening the 

treatment of hydraulics within eddies, given the importance of this portion of the river system for 

sediment dynamics. Evaluation of different management scenarios requires a 2-3 eddy-length 

multidimensional model that can be tested during experimental flow releases. 

The model contains many simplifications, among which reach averaging, equilibrium, 

and one-dimensionality are the most significant. Given these simplifications, there is no reason 

to expect that theoretical coefficients would produce optimal results. Thus, the model must be 

calibrated. In addition, the equilibrium assumption is not applicable to experimental floods that 

are the primary application of the model, so the assumption should be removed from the model. 

For example, simulation of the 2004 experimental flood featured too much sediment arriving too 

soon at mile 30. This could result from the assumption of equilibrium, or from a settling velocity 

that is too small for the well-mixed cross section. At mile 87 the results were better, which is 

unusual because errors normally propagate downstream. The assumption of equilibrium would 

get better with distance downstream, so it is likely that the equilibrium assumption is the primary 

cause of the poor results at mile 30. Part of the problem is that the model remains at the stage of 

preliminary testing. Proposed calibration of the model using existing 2007 funds will presumably 

lead to future improvements. 

The panel believes that the fine sediment model needs to have the capability to (i) 

simulate a range of flow scenarios, (ii) account for eddy storage dynamics to at least a first-order 

approximation, and (iii) better address reach-scale processes. Essentially, the model needs to 

provide first-order estimates of the effects of different management scenarios, although in order 

to do this it may be necessary to run 2d or 3d models of specific processes such as eddy 

dynamics, for which field-based hydraulic measurements will be needed. The initial, onedimensional theoretical model without calibration has been used to assess general model trends, 

and this approach indicates that the model has promise. The model now needs further refinement 

and calibration and the panel suggests that the modeling team develop shorter time-step, more 

detailed simulations that are used to parameterize longer model runs that can then be applied to 

scenario testing as a management tool (for e.g., evaluating relative sediment input, sediment 

retention, and sediment output). The lack of detailed measurements during periods of change 

limits modeling efforts. Measurements of hourly to daily changes over a time period of days on a 

reach basis, for example, are necessary for the fine sediment model to be useful for management. 
12

The modelers first need to demonstrate that the model works on a simplified, theoretical or 

laboratory-type example, however, and this has not yet been shown by Wiele’s group. At this 

point, the existing model needs further work to make it applicable to evaluating different 

management scenarios, and this in turn requires much closer collaboration between modelers and 

field-based researchers. One way to facilitate this closer collaboration and to ensure that the fine 

sediment model meets the needs of the mass balance and FIST groups would be for GCMRC 

rather than other USGS offices to lead the modeling program. The FY2007 statement of work 

for modeling appears to accomplish this. One of the primary reasons that the earlier panel 

recommended concentrating on several reaches for the FIST monitoring effort was to provide the 

three-dimensional geometry and temporal history of fine sediment storage that could be used in a 

two-stage approach of using Wiele’s 2+d model to calibrate the one-dimensional model. The 

FIST reaches do not appear to have been utilized in this way. 

A weakness of the present modeling efforts resides in the lack of quality control of the 

model and its solution. There are recommended practices that should be followed by any general 

modeling program, and those have not been followed here. These practices have been 

standardized across disciplines by the AIAA (American Institute of Aeronautics and 

Astronautics), the ASME (American Society of Mechanical Engineering) and the ASCE 

(American Society of Civil Engineering), which publish those standards in manuals and other 

practice recommendation documents. Wiele and coworkers are referred to those documents and 

encouraged to follow them in future work. 

Assessing thresholds. Another issue relevant to data collection and modeling is how well 

physical resources scientists need to know the parameters and trends that they study. This issue 

can be paraphrased by asking, “Where is the elbow curve in a data set?” In other words, rather 

than focusing on detailed resolution, it may be most effective for project scientists to understand 

trends and thresholds within the river ecosystem. Given that the level of effort needs to be 

commensurate with the set of objectives identified, scientists involved in modeling and 

monitoring need to consider how to assess, for example, whether they’ve reached an 80% level 

of understanding of the system. Individual physical resources scientists are constantly assessing 

their level of accuracy, which is admirable, and the panel commends this as a strength of the 

program. However, there may be unnecessary overlap in current measurement programs, such as 

using both LISST and multifrequency acoustics. The LISST appears to provide valuable data, 

but requires an extraordinary amount of maintenance. Is the added value worth the cost? Could 

the system be monitored to an acceptable level with only multifrequency acoustics? If the LISST 

is needed, it is likely that the initial cost of installing LISST Infinities would be recovered in 

reduced maintenance costs. An analysis of this and associated costs should be developed. Project 

scientists should carefully consider what would be the minimal instrumentation needs to derive a 

trigger for an experimental flow release. The monitoring requirements to identify a trigger may 

be different than the monitoring requirements to track the short-term and long-term response to 

the triggered release. (An example might be discharge and sediment using acoustics and eventdriven sampling at the Paria, LCR (Little Colorado River), and Diamond Creek, with 20% 

accuracy in the associated rating curve.) 
13

Core monitoring and analysis. Monitoring, applied studies, and modeling form the three 

basic components of the physical resources program of GCMRC. Monitoring activities feed 

directly into the identified CMIN (core monitoring information needs), applied studies address 

key uncertainties, and modeling ties all three components together and provides a framework for 

the physical resources program and for scenario evaluation. The panel suggests that all three of 

these components be collectively referred to as core monitoring and analysis because effective 

monitoring requires interpretation, as provided by applied studies and modeling, that can inform 

adaptive management. 

Experimental flows. Experimental flow releases remain critical to the core monitoring 

and analysis program. These flows form an integral part of monitoring because they create 

episodic changes in the river ecosystem that can be planned for and measured, and thus provide a 

platform for calibrating conceptual and numerical models, and testing model predictions. The 

November 2004 flood provides a good example of adaptive management. The experimental 

release that created this flood was triggered by a naturally occurring flood on the Paria River. 

The November 2004 flood reversed much of the recent erosion on sand bars, but did not restore 

bars to pre-1990 condition. The flood also demonstrated the existence of “hot spots” where most 

of the change in sediment storage occurs. 

Because experimental flows remain critical to achieving understanding of the Colorado 

River ecosystem, these flows must continue. One of the largest constraints on the ability of the 

physical resources program to learn is the lack of experimental flows. Scientists in the physical 

resource program have not yet evaluated the ability of annual or biannual experimental flows to 

build sustainable beach habitat and have not addressed the question of how to manage flows in 

order to conserve sand bars following experimental releases, for example. Scientists will 

probably need further experimental releases in order to address these critical questions. 

Experimental flows are necessary to adaptive management, and may result in operational 

flexibility that is not yet recognized as being possible. The use of scenarios modeled by an 

appropriately developed model could help provide justification to the AMWG that the costs of 

experimental floods are justified. The model may need to be revised as data collected during 

these floods are analyzed, but that is the heart of the adaptive management process. The lack of a 

model to show potential results may be hindering the project from moving forward. 

Sediment monitoring strategies. Lacking specific metrics to guide monitoring, at least 

three complementary but potentially redundant approaches exist with respect to sediment 

monitoring in the Colorado River ecosystem. The first approach is to detect the trend of change 

in sand bar area and volume. This is only a first-order determination, yet is one of the more 

difficult to accomplish. In this context, the panel commends the works of the NAMDOR team in 

producing ground-based survey data that are critical to evaluating bar changes. The minimalist 

monitoring to accomplish detection of trends in sand bar area and volume is repeat surveys of 

existing, established sites on a regular basis, such as once a year, using ground-based techniques. 

This would provide the ability to detect long-term trends through time, but would not provide 

any insight into cause and effect or into impacts of changing flow regime. Adding event-based 

surveys to the annual surveys would increase the ability to detect the influence of controlled 
14

floods or fluctuating flow regime. The most effective monitoring will be sufficiently flexible and 

responsive to utilize unexpected events, such as sediment inputs from the Paria or LCR, as well 

as planned events such as controlled floods on the main channel. 

The second approach for monitoring sediment is to track inputs, storage, and outputs for 

a sediment mass balance. This provides the ability to quantify a trigger for beach habitat building 

flows (BHBFs). Continuing key uncertainties in using the mass balance approach include inputs 

from the Paria and the LCR, how much sediment remains stored in the main channel, and how 

much sediment has moved through the river system. Further quantifying the mass balance will 

provide insight into these unknowns for future controlled floods. A minimal level of mass 

balance would be based on considering only inputs. A more robust mass balance would also 

include outputs and overall mass balance. The panel believes that it is critical to have the more 

robust mass balance because our understanding of the system is insufficient at this point to make 

recommendations about controlled floods. The more robust mass balance should include 

monitoring of bed sediment grain size and density of coverage based on research results to date, 

although it remains unclear whether bed sediment size is causal or correlative with supply and 

transport history. 

The third approach for monitoring sediment is to continue a full FIST approach to 

identify changes in the spatial distribution of sediment on the bank and bars in long reaches of 

the river. This approach would include detailed, event-based measurements of hydrodynamics 

and sediment transport in multiple eddies. The approach would provide the largest spatial 

distribution of data, but may be limited in accuracy because of the uncertainty associated with 

remote sensing data and surficial bathymetric surveys that cannot quantify the depth and 

composition of the bed material. 

It is unlikely that approaches 1 and 3 could provide the level of detail needed to trigger 

BHBFs or to develop and validate a sediment transport model of the system. Approach 2 can 

only provide information on how much sediment is stored or eroded, but not on where the 

storage or erosion is occurring in the system. A combination of approaches is therefore required, 

and all approaches need to be part of a unified and integrated work plan. Until the final results of 

the remote sensing data are completed, its usefulness compared with cost cannot be determined. 

There is always value in long-term data sets and for this reason the repeated ground surveys of 

the NAU sites should be continued. Based on the results of the remote-sensing data, it may be 

beneficial to reduce the number of NAU sites while expanding the spatial distribution with 

remote-sensing data. This determination will have to be made by the project staff once the 

processing and analysis of the remote sensing data are complete. 

It will be the task of managers, as guided by recommendations from program scientists 

and peer reviewers, to choose among the alternate approaches for sediment monitoring. This 

panel recommends employing the first two approaches by continuing both annual and eventbased ground monitoring of sand bars, and continuing development of the sediment mass 

balance for the river ecosystem. The panel also emphasizes that it is essential that funding for all 

existing research efforts continue for a sufficient period of time to allow the scientists to analyze 
15

their data in order to recoup the GCMRC’s existing investment. 

Potential for integration of sediment core monitoring protocols with other related program 

activities and objectives 

 The degree of integration among the three core programs of the GCMRC has improved 

since 1999, but the programs are not yet effectively integrated. The panel recommends the 

following actions as means to foster integration among the programs: 

• Establish common frames of reference that facilitate discussion of effects of changing 

flow and sediment regimes among scientists in the three programs. Stage in relation to 

discharge provides an example of such a frame of reference; discussing various flow 

scenarios with respect to stage would facilitate quantification of parameters such as fish 

habitat or camping area on bars, which are of particular concern to the biological and 

sociocultural programs, respectively. 

• Evaluate trade-offs among different resources as a function of differing flow regimes. For 

example, how does a specific flow scenario affect survival of humpback chubs versus 

camping space versus preservation of archeological sites? Scientists in the physical 

resources program need to consider not just bar building, but also what comes after with 

respect to the continuing effects of different flow scenarios. The concept of trade-off 

space represents a higher objective for the monitoring program that would facilitate 

comparison of trade-offs among the multiple objectives articulated by stakeholders in the 

adaptive management process. 

• Identification by scientists in other programs of physical parameters which are central to 

their understanding of the river ecosystem. Scientists in the physical resources program 

have impressive measurement capabilities for many parameters that are likely to be 

important to scientists in other programs, but integration is limited if the physical 

scientists are not informed of these parameters, and of the spatial and temporal resolution 

of measurements most useful to scientists in other programs. What level of detail do 

biologists want for quantifying aquatic and riparian habitat, for example, with respect to 

area, volume, or substrate type? What other types of measurements (e.g. water 

temperature, dissolved oxygen) could be emplaced at existing flow and sediment 

measurement sites that would be useful to biologists? 

• Joint annual research symposia and river trips by scientists in the three core monitoring 

and research programs that are organized specifically to identify common frames of 

reference and to evaluate trade-offs among resources under differing management 

scenarios would foster collaboration and integration, and should ultimately facilitate use 

of an ecosystem-level adaptive management model. 

• As noted earlier in this report, many of the 1999 recommendations of the PEP SEDS 

panel have been implemented by the GCMRC staff and scientists. It is not clear to the 

panel that this type of follow-through occurs as consistently in other programs. Serious 

attention to external review and implementation of review recommendations by other 

programs within GCMRC would provide important impetus to these programs and would 

facilitate integration among programs. Many of the recommendations from the most 
16

recent panel review for the sociocultural program are directly related to sediment issues, 

for example, as are many of the objectives of both the biological and sociocultural 

programs, albeit on different time scales. 

Responses to specific questions and recommendations from scientists in the physical resources 

program

• The FIST data would need to be fully evaluated in relation to the mass balance and NAU 

data before the panel could recommend continuation of one versus the other. The 

physical resources program lacks consistent cross-comparison of different approaches 

within the same frame of reference, which hinders recommendations for prioritizing 

ongoing data collection efforts. True evaluation of the effectiveness of different 

approaches requires more integrated, comprehensive analysis of results and comparison 

between methods. FIST has not yet facilitated calibration and validation of Wiele’s 2d 

model, which was part of the original intent of implementing FIST. The original intent of 

FIST was to inform detailed models, which would then inform bin-based models. The 

FIST group collected the type of data intended, but these data have not been utilized by 

modelers. 

• At this point, the panel does not consider it necessary to add further monitoring sites 

downstream from Phantom Ranch, but this may need to be revisited (presumably by 

stakeholders) in the future. 

• The fact that much remains to be learned about where bars will be built or reduced as a 

function of flow magnitude, duration, and timing with respect to tributary sediment 

inputs argues for development of a robust sediment mass balance that includes the 

transport and export of sediment. As part of this, the panel endorses the goal of reducing 

error in the sediment mass balance by obtaining better data (particularly high flow data) 

from the Paria River. 

• Work to date on LiDAR is very impressive and is useful for monitoring changes in beach 

area and vegetation cover. The panel recommends continued use of LiDAR, although this 

may not be necessary every year or with continuous coverage of the Colorado River 

ecosystem. LiDAR surveys should be carefully designed to provide information to all 

three GCMRC programs. LiDAR may be more effective as a targeted tool that is used in 

combination with ground-based surveys. Evaluations of different techniques would be 

facilitated by detailed comparisons such as ground-based versus LiDAR bar cross 

sections, or changes in volume, area, or vegetation cover of bars; fish finder versus NAU 

bathymetric surveys; or NAU versus FIST surveys for trend analysis of bars. Evaluations 

within individual data sets would also help to address questions such as whether fewer 

than 45 sections can be used for NAU surveys. The panel suggests that project scientists 

consider using the Kruskal-Wallis rank test or a similar statistical test to address this 

question. 

• Topping and Rubin have already done a tremendous amount of work, but the panel 

questions their ability to make substantial additional progress without more clearly 

articulated goals within the overall sediment program. At present, they can provide a 

sand budget for the river ecosystem, the NAU group and Jack Schmidt can provide bar 
17

area, and Rubin and Roberto Anima can provide bed composition. All of these elements 

can now be tied together. Wiele’s 1d sediment transport modeling is a good start at tying 

these different data sets together, but work is needed on model calibration rather than on 

further model development. 

• The panel recommends that Topping and other physical resources program scientists 

consult with experts on error and uncertainty, such as Tim Cohen of the U.S. Geological 

Survey, Office of Surface Water, in Reston, Virginia. 

• The panel recommends careful consideration of cost-benefit ratios for all monitoring and 

analysis techniques used in the physical resources program. 

• The panel and GCMRC need a better-coordinated scheme for identifying the type of 

information now critical to modeling efforts in order to prioritize funding for continued 

monitoring and research efforts versus new directions. 

• The qualities of “sustainable” or “attainable” conditions in resources need to be more 

precisely defined to guide monitoring. 

• The panel feels that David Topping plays an essential role in this program. He does very 

high quality work and has many skills that cannot be replicated by other scientists 

involved in the program. The innovative nature of the sediment mass balance that he has 

developed is admirable. The panel views his participation in the physical resources 

program as essential, and recommends that anything that would facilitate his continued 

participation should be endorsed because he plays such a unique role. Program success 

likely would considerably diminish without his presence at GCMRC and institutional 

knowledge, and his progress over the last decade has been phenomenal. 

III. SUMMARY

 In summary, the review panel commends the physical resources program director and 

contributing scientists for the progress made with respect to core monitoring and analysis since 

the 1999 program review. Although the panel believes that many specific improvements can be 

made within the physical resources program and in cross-program linkages within GCMRC, we 

think that the physical resources program is proceeding in a manner that will be effective in 

addressing core monitoring information needs and strategic science questions. 

The panel stresses the need for more experimental releases in order to assess the 

adequacy of any model that program scientists use to predict changes in bar distribution and size. 

Continued experimental flows are critical to resolving the complex uncertainties of bar dynamics 

in terms of how variations in flow magnitude, duration, and timing influence sand transport and 

storage. The lack of experimental flows constrains the ability of scientists and managers to learn 

and predict because experimental flows are not solely research tools, but also function as 

monitoring and management tools that reflect the outcome of alternative strategies of dam 

management. Monitoring of system responses to experimental flows will allow identification of 

flexibility within the river ecosystem with respect to parameters such as ramping rates and daily 

fluctuations. Experimental flows may provide a better, faster, and cheaper alternative than using 

a sediment pipeline to restore declining sand bars within the Colorado River ecosystem. Because 
18

scientists studying this ecosystem are not yet able to specify the characteristics of experimental 

floods necessary to preserve or restore sand bars, experimental flows remain critical to 

monitoring how the system responds to high flows. The crux of adaptive management is to 

experiment, monitor, design management, and experiment again until the desired state is 

achieved and, in the Colorado River ecosystem, this process requires experimental flow releases. 

 The panel believes that the greatest opportunities for learning presently lie in addressing 

issues such as (i) plausibly simulating a multi-eddy, multi-bar system and linking this to 

management scenarios, (ii) better understanding the spatial organization of the Colorado River 

ecosystem, and (iii) developing a better sense of trajectories in the system following different 

release schedules (existing sediment research, for example, seems to support the idea of relaxing 

restrictions on daily flow fluctuations). One type of data collection is necessary for 

understanding a complex system, and this is now largely complete for the physical resources 

component of the Colorado River ecosystem. Another type of data collection is necessary for 

monitoring the system, and this should be the continuing focus of the GCMRC physical 

resources program. 

 As noted in the final report of the 1999 physical resources program review panel, 

excellent progress continues to be made in developing an understanding of the physical behavior 

of the Colorado River in Grand Canyon. The physical resources program is well managed and 

integrated. The quality of the overall research and monitoring effort is exceptionally high. The 

effectiveness of the physical resources program, and the GCMRC as a whole, can be improved 

by attention to the issues highlighted in this report, which include: 

• clear articulation of a structured approach that guides core monitoring and analysis 

efforts in each research project and in all GCMRC programs 

• closer integration within the physical resources program between efforts aimed primarily 

at monitoring and applied studies, and efforts to develop integrated models of hydraulics 

and sediment dynamics within the river ecosystem 

• integration of frequent experimental releases into core monitoring and analysis 

• development of a common frame of reference and discussion of trade-offs among 

differing resources under varying flow regimes by scientists in all three GCMRC 

programs 

• consideration by physical resources scientists of issues of resolution versus trends and 

thresholds in the parameters being measured or modeled with respect to a context of 

adaptive management 

• development of a monitoring plan based on a structured approach and including details of 

techniques to be used, desired spatial and temporal resolution of data collection and 

modeling, and data storage and retrieval 

Appendix 1. Review Elements 
19

1. Please comment on any long-term sediment monitoring protocols identified or 

recommended by the GCMRC staff during the SEDS-PEP III meeting for FY 2008 and 

beyond. 

2. Please review and evaluate all written suggestions or recommendations for future longterm sediment monitoring and modeling provided by other cooperating scientists during 

the August 15-17, 2006 meeting. 

3. Please review and provide comments on draft statements of work proposed for FY 2007 

(a) integrated quality-of-water core monitoring – with emphasis on sediment elements 

(Topping and others), and (b) proposal for modeling support linked to integrated qualityof-water core monitoring (Wright and others). 

4. Please provide evaluations of how effectively the panel thinks the sediment scientists’ 

monitoring recommendations will be in meeting the identified core monitoring 

information needs for sediment goals and management objectives. 

5. Please comment on how effective the current or proposed sediment core monitoring 

(presumably, in combination with sediment flow experiments and modeling activities) 

will be in answering the strategic science questions that have been recently identified for 

sediment resources (sustainable sand bar restoration through implementation of BHBF 

and possible optimization). 

6. Please comment on potential for integration of the sediment core monitoring protocols 

with other related program activities and objectives. 

Appendix 2. Strategic Science Questions 

Strategic Science Questions developed cooperatively by scientists and managers as a 

result of the Knowledge Assessment Workshops in 2005 

4.1 Physical Resources 

4.1.1 Is there a “Flow-Only” (non sediment augmentation) operation that will restore and 

maintain sandbar habitats over decadal time scales? 

4.1.2 Is there an optimal strategy for BHBF implementation to manage tributary inputs on an 

annual to inter-annual time scale? 

4.1.3 What are the short-term responses of sandbars to BHBFs? 

4.1.4 What is the rate of change in eddy storage (erosion) during time intervals between 

BHBFs? 

4.1.5 How does the grain-size distribution of the deposits affect sandbar stability? Main 

channel turbidity? 

4.1.6 What are the effects of ramping rates on sediment transport and sandbar stability? 

4.1.7 Can we develop a relationship between suspended sediment concentration and turbidity 

to support fisheries research? 

Appendix 3. Suggestions or recommendations for future long-term sediment monitoring 
20

and modeling provided by project scientists 

Set 1. Future Sand Modeling Activities 

Peter Wilcock and Stephen Wiele 

We have demonstrated the viability of the reach-averaged approach to modeling sand routing 

and its application to the Colorado River in Grand Canyon. An uncalibrated model provides a 

good fit to the 2004 flow and transport conditions. We will develop example applications to 

management questions and collaborate on delivery of a Graphical User Interface with Josh 

Korman, completing work on the first version of sand routing model. 

As designed, the sand routing model addresses questions of sand routing and storage 

corresponding to management actions and tributary events over a time frame of days to months. 

The model can be used to evaluate dam release scenarios for conserving tributary sand supplies 

prior to high flow releases. The model is intended to assist in determining the most effective dam 

operations for conserving tributary sand inputs. 

Broader questions arise regarding the long-term sand balance. Can sand conservation flows and 

BHBFs maintain or increase the amount of sand stored in the system? Is sand augmentation 

necessary to increase the amount of stored sand and, if so, in what quantities? The completed 

sand routing model can be used to evaluate dam releases, tributary supplies, and sand 

augmentation in terms of optimizing storage of introduced sediment, but the long term balance 

depends also on the rate at which sand is lost from eddies over long time periods between high 

flow events. To complete our ability to model the long-term effects of management actions on 

the sand resource, the short-term sand routing model will need to be coupled with a long-term 

eddy sand loss model. The long-term model will need to be developed in close coordination 

with long-term field monitoring of changes in eddy sand volume in order to constrain model 

error accumulated over long computational periods. This will require a focused research effort 

that includes (1) monitoring of sand loss over long periods with no high flows and different 

initial conditions of sand storage and (2) a model framework combining the relevant mechanisms 

with long-term constraints based on observations of eddy sand loss. 

Set 2. Downstream Integrated Quality-of-Water Monitoring (below Glen Canyon Dam) 

David Topping, Scott Wright, and David Rubin 

The downstream IQW project focuses mostly on monitoring, but can also support 

implementation of flow research related to stable flow testing, evaluation of alternative 

fluctuating flows, tests of BHBFs and ongoing development and evaluation of numerical 

modeling. In some instances, it is difficult to separate these elements from experimental 

elements because they support each other. For example, monitoring the suspended sediment 

budget may be considered core monitoring, but it is also required to assess a 

trigger for a BHBF such that it could be considered experimental research support. In the 

section on project goals/tasks, the individual project elements are described along with 

the associated category(s). This project is intended to provide core-monitoring information to 
21

meet the information needs of the GCD AMP related to Goals #7 and #8 under an ongoing 

schedule during FY 2007 and beyond. 

Geographic Scope: 

The downstream IQW project is primarily focused on the main channel of the Colorado 

River from just below Glen Canyon Dam (mile -15) downstream to Diamond Creek (mile 

226). However, an important component of the project is a combination of monitoring 

and modeling of tributary sediment inputs such that sediment and flow monitoring 

activities are also carried out in various tributary watersheds, such as the Paria and Little 

Colorado Rivers. 

Project Goals/Tasks: 

The downstream IQW monitoring project is focused primarily on measurements of 

surface flow throughout the river ecosystem, as well as quality-of-water parameters such 

as temperature, specific conductivity, dissolved oxygen, and suspended-sediment 

transport. The monitoring project directly supports achievement of the following GCD 

AMP goals: 

Goal 7: Establish water temperature, quality, and flow dynamics to achieve GCD AMP 

ecosystem goals. 

Goal 8: Maintain or attain levels of sediment storage within the main channel and along 

shorelines to achieve GCD AMP ecosystem goals. 

Because this monitoring project addresses the physical framework of the ecosystem, which 

underlies many biological, cultural, and recreational resource objectives, it indirectly supports 

achievement of almost all other GCD AMP goals, as described below: 

Goal 1: Protect or improve the aquatic food base so that it will support viable populations of 

desired species at higher trophic levels. 

The downstream IQW project supports this goal by providing information on flows, water 

temperature, and turbidity that aids in food base studies, such as the assessment of primary 

productivity and allochthonous inputs. 

Goal 2: Maintain or attain a viable population of existing native fish, remove jeopardy for 

humpback chub and razorback sucker, and prevent adverse modification to their critical habitats. 

The downstream IQW project also supports the native fish program by 

providing near-shore water temperature data for the assessment of growth rates, sediment 

concentration data that is used to adjust for catch efficiency in population models, flow and stage 

data that is important to understanding the effects of near-shore habitat disruption caused by 

fluctuating flows, and information on sandbars which create 

backwater habitats that are thought to be important for native fish. 

Goal 4: Maintain a wild reproducing population of rainbow trout above the Paria River, to the 

extent practicable and consistent with the maintenance of viable populations of native fish. The 

downstream IQW project also monitors dam release and Glen 

Canyon quality-of-water, which proved critically important in fall 2004 when dissolved oxygen 

levels were low requiring modifications to release patterns in order to raise oxygen levels. 

Goal 6: Protect or improve the biotic riparian and spring communities within the Colorado River 

ecosystem, including threatened and endangered species and their critical habitat. The 

downstream IQW project also tracks the transport and fate of fine sediment, which provides the 

substrate for riparian vegetation and marsh communities. 
22

Goal 9: Maintain or improve the quality of recreational experiences for users of the Colorado 

River ecosystem within the framework of GCD AMP ecosystem goals. The downstream IQW 

project also produces monitoring data and supports experimental and modeling research to 

understand flow dynamics and the size and abundance of sandbars, which are resources that 

affect the recreational experiences of Colorado River users such as rafters and fishermen. 

Goal 11: Preserve, protect, manage, and treat cultural resources for the inspiration and benefit of 

past, present, and future generations. The downstream IQW project also provides monitoring 

data related to riverine sand bars that provide a source of sediment, through aeolian transport, to 

high elevation sand deposits that contain archaeological 

resources. In addition, the downstream IQW project has also developed stage modeling 

capabilities that allow for the assessment of the flow level that inundates a given cultural site. In 

August 2004, the AMWG reviewed these goals and identified priority questions. The top five 

priority questions are as follows: 

Priority 1: Why are the humpback chub (HBC) not thriving, and what can we do about it? How 

many humpback chub are there and how are they doing? 

Priority 2: Which cultural resources, including Traditional Cultural Properties (TCPs), are 

within the Area of Potential Effect (APE), which should we treat, and how do we best protect 

them? What are the status and trends of cultural resources and what are the agents of 

deterioration? 

Priority 3: What is the best flow regime? 

Priority 4: What is the impact of sediment loss and what should we do about it? 

Priority 5: What will happen when a Temperature Control Device (TCD) is tested or 

implement? How should it be operated? Are safeguards needed for management? 

As with the AMP goals, the IQW monitoring directly supports some priorities while 

indirectly supporting others. For example, monitoring and research on flows, sediment 

transport, and water temperature clearly directly support priorities 3, 4, and 5, while also 

indirectly supporting priorities 1 and 2 by providing information on the general physical 

framework of the riverine environment. 

There are several project related tasks that occur within the downstream IQW project: 

• Flow and stage monitoring: Continued monitoring of flow and stage at established mainstem 

locations and major tributaries (-15-mile, 0-mile, 30- mile, 61-mile, 87-mile, 226-mile, Paria, 

and Little Colorado Rivers). 

Category(s): Core Monitoring. Schedule: Ongoing. 

• Quality-of-Water monitoring: Continued monitoring of water temperature at established 

mainstem locations and major tributaries (-15-mile, 0-mile, 30-mile, 61-mile, 87-mile, 166-mile, 

226-mile, 246-mile, Paria and Little Colorado Rivers, Kanab, Havasu). Implement of a new 

nearshore/backwater temperature monitoring program. Continued 

monitoring of conductivity at established stations (-15-mile, 0-mile, 30-mile, 61-mile, 87-mile, 

226-mile). Continued monitoring of turbidity at established stations (30-mile, 61-mile, 226-

mile).Category(s): Core Monitoring. Schedule: Ongoing for mainstem temperature, conductivity, 

and turbidity monitoring; implementation of nearshore/backwater monitoring program in FY07, 

then ongoing; monitoring data supports completion of downstream thermal model development 

during FY07, applications ongoing. 

• Suspended-sediment flux monitoring: Continued monitoring of suspended-sediment flux at 
23

established mainstem locations and major tributaries (30-mile, 61-mile, 87-mile, 226-mile, Paria 

and Little Colorado Rivers). Because BHBF triggers are based on sediment retention within the 

mainstem, it is insufficient to monitor tributary inputs only. 

Category(s): Core Monitoring. Schedule: Ongoing. 

• Collaboration with and support of aquatic food base program: Integrated research studies with 

the aquatic food base program, including submerged aquatic vegetation and bed texture 

classification with acoustics, monitoring algal drift with acoustics, and quantification of tributary 

inputs of organic material. Category(s): support for Research and Development. Schedule: 

Ongoing. 

• Coordination with other resource areas: Regular meetings and interaction with other resource 

area personnel, particularly at the Program Manager level, in order to facilitate an ecosystem 

approach to our scientific studies and ensure that the IQW is providing useful information 

regarding the physical environment to the other resource areas. Category(s): Program 

Management. Schedule: Ongoing. 

Need for the Project: 

Information on flow, water quality, and suspended-sediment transport is critical to 

understanding the physical environment upon which biological and socio-cultural 

resources depend (see details in Section 1 of this project description). In order to 

understand responses of these resources to dam operations, we must first understand the 

effects of dam operations on the physical environment. The goal of the downstream IQW 

project is to provide this information and link dam operations to changes in the physical 

environment. 

Strategic Science Questions: 

The downstream IQW monitoring project is designed with the goal of providing data that 

supports answering the two primary physical resources questions identified during the 

Knowledge Assessment Workshop conducted in the summer of 2005, as follows: 

• Is there a “Flow-Only” operation (i.e. a strategy for dam releases, including managing tributary 

inputs with BHBFs, without sediment augmentation) that will restore and maintain sandbar 

habitats over decadal time scales? 

• How do dam release temperatures, flows (average and fluctuating component), meteorology, 

canyon orientation and geometry, and reach morphology interact to determine mainstem and 

near shore water temperatures throughout the CRE? 

Also, as detailed throughout this project description, the IQW project provides information on 

the physical environment that is critical to other resource areas and will thus contribute indirectly 

to answering a variety of other science questions related to other resources. 

Links/Relationship to Other Projects: 

Aquatic Food Web Research: The downstream IQW project supports new research 

focused on the food web of the river ecosystem by providing continuous data on surface 

flow in the main channel and major tributaries, as well as related quality-of-water data, 

such as water temperature, specific conductivity, dissolved oxygen and suspendedsediment 

concentrations and grain size for suspended particles in transport. 

Fisheries Monitoring and Research – the IQW also supports science activities in 

the fisheries program by providing flow and quality-of-water data that may be used by 

the fisheries biologist in evaluating their fish catch data, as well as growth, movement 
24

and habitat use information. 

Information Needs Addressed: 

The downstream IQW project directly addresses several of the core monitoring and 

research information needs (CMINs and RINs) related to AMP Goals 7 and 8. A 

selection of the information needs that are addressed by IQW are listed below. The IQW 

addresses many more CMINS, but the ones listed below are considered most relevant to 

answering the science questions outlined above. 

• CMIN 7.4.1 Determine and track flow releases from Glen Canyon Dam under all operating 

conditions. 

• CMIN 7.1.2 Determine and track LCR discharge and temperature near the mouth (below 

springs). 

• CMIN 7.1.1 Determine the water temperature dynamics in the mainstem, tributaries, 

backwaters, and near-shore areas throughout the Colorado River ecosystem. 

• CMIN 8.1.3 Track, as appropriate, the monthly sand and silt/clay –input volumes and grainsize characteristics, by reach, as measured or estimated at the Paria and Little Colorado River 

stations, other major tributaries like Kanab and Havasu creeks, and “lesser” tributaries? 

• CMIN 8.1.2 What are the monthly sand and silt/clay export volumes and grain-size 

characteristics, by reach, as measured or estimated at Lees Ferry, Lower Marble Canyon, Grand 

Canyon, and Diamond Creek Stations? 

The monitoring data from IQW not only fulfill the CMINs listed above, but are also 

intended to feed new information directly into modeling efforts (see Project PHY 07.R1.07) that 

will allow sediment-transport modelers the opportunity to address research information needs 

(RINs) related to AMP Goals 7 and 8. 

• RIN 7.4.1: What is the desired range of seasonal and annual flow dynamics associated with 

power plant operations, BHBFs, and habitat maintenance flows, or other flows that meet AMP 

goals and objectives? 

• RIN 7.3.1: Develop simulation models for Lake Powell and the Colorado 

River to predict water quality conditions under various operating scenarios, supplant monitoring 

efforts, and elucidate understanding of the effects of dam operations, climate, and basin 

hydrology on Colorado River water quality. 

• RIN 8.5.1: What elements of Record of Decision operations (upramp, downramp, maximum 

and minimum flow, MLFF, HMF, and BHBF) are most/least critical to conserving new finesediment inputs, and stabilizing sediment deposits above the 25,000 cfs stage? 

General Methods: 

Flow, stage, water temperature, conductivity, turbidity and suspended-sediment data are 

collected using standard USGS protocols with QA/QC. Suspended-sediment sampling is 

supplemented through the use of emerging technologies, including acoustics and laser 

diffraction. Stage, water temperature, conductivity, turbidity, and suspended-sediment surrogates 

(i.e. acoustics and laser-diffraction) are monitored with in-situ instrumentation recording at 15-

minute intervals. River flow is measured periodically and used to develop a stage-discharge 

rating curve, providing 15-minute flow records. Similarly, suspended-sediment concentration is 

measured periodically and used to calibrate and acoustic and laser diffraction instrumentation, 

providing 15-minute records of concentration (sand, silt/clay, and sand grain-size). 

Products/Reports: 
25

The following products/reports are expected on an annual basis: 

• Streamflow, stage, and tributary sediment data published in annual Arizona Water Resources 

Data reports and served through the GCMRC webpage. 

• Biennial Data Report summarizing mainstem sediment transport and water quality data; data 

also served through the GCMRC webpage. 

• 2 – 4 conference abstracts and proceedings articles 

• 1 – 3 journal articles 

• Frequent presentations at stakeholder meetings. 

Set 3. Bar Monitoring 

David Rubin and FIST participants 

Bar surface area: 

Should have higher priority than bar volume because area is how the resource is used (real estate 

lots are sold by area--rather than volume--for a reason). Also, area (such as area above 8000 cfs) 

can be measured at lower cost and with lower error than volume. Could be measured by 

surveyors on the ground at edge of water, from air photos, or lidar--whichever has the best 

balance of coverage and accuracy to cost. Frequency of measurements could be every year for 

selected bars and campsite areas, every few years or pre- and/or post-flood for longer reaches or 

more bars, and every 5-10 years for a larger region (entire river corridor). 

Bar volume: 

Should have lower priority than measuring area because of greater cost and lower benefit. Too 

early to decide what is the best surveying technology, sampling strategy, or recommended time 

interval. 

Grain size: 

Reasons for mapping grain size: 

(1) Monitoring requested by managers 

(2) Learn how to design more effective monitoring plans for the future (compare results with 

beta-calculations and shifting rating curves) 

(3) Learn how the river works, where fine sediment is stored, how long it resides in different 

locations 

(4) Extremely inexpensive (compared to bathymetric mapping and mass-balance monitoring) 

Recommended near-term plan: 

(1) Map grain size using eyeball in cooperation with other bathymetric surveying trips, 

preferably before and/or after each flood, a minimum of once each year 

(2) Recent surveys have collected in excess of 5000 images per trip (approximately 1000 

locations with 5 images per location). The estimated error (95% confidence) in the mean for 

such large samples with the observed standard deviation is only 10% of the grain size. 

Because the estimated error in the mean scales with the square root of the number of samples, we 

could get by with fewer samples, provided we don't sacrifice spatial coverage. We therefore 

recommend streamlining the operation by collecting and processing fewer images per location 

(rather than fewer locations). 
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(3) In our existing data-processing scheme, the most time-consuming step is frame-grabbing of 

images from the digital video tapes collected in the field. Our existing digital recorder has a slot 

for inserting a memory card for still-image capture. We recommend using this feature to grab 

frames in the field (and collect the digital tape primarily as a back-up, or for replacement of any 

defective images grabbed in the field). 

(4) We recommend using whatever navigation system is most compatible with other 

simultaneous field operations: (a) using a combination of monumented cross-sections (for 

longitudinal location) and pressure transducer on the eyeball housing or markings on the eyeball 

cable (for depth and therefore transverse location using surveyed depths for that cross-section), 

(b) gps, or (c) tracking by laser surveyor. 

Set 4. Sand Bar Monitoring 

Matt Kaplinski and Joe Hazel 

1) Measuring bar volume and topography/bathymetry provides additional information not 

included in measurements of area alone. 

2) Errors arise if bar area is mapped while water discharge is changing 

3) Measuring area at low, steady discharge might not save money.