Stillwater Sciences is passionate about watershed science. We approach watershed analysis and restoration with rigorous science, innovation, and a collaborative decision-making process. We strive for simple, integrated solutions

to complex and unwieldy environmental problems. Sound interesting? Learn more at www.stillwatersci.com.

Stillwater Sciences

Stillwater Sciences specializes in science-based approaches to environmental issues. By integrating geomorphic and biological studies to understand critical ecosystem processes, we work to identify ef-fective measures for restoring and managing rivers, their floodplains, and whole watersheds as func-tioning ecosystems. We regularly collaborate with university academics and other expert scientists to maintain the highest scientific standards, and we apply current research findings to watershed issues. With a reputation for objective work and a high respect for our staff from state and federal agencies, non-governmental organizations, and industry, Stillwater has a proven record of effectively bringing stakeholder groups to agreement on the basis of objective, credible scientific data and analysis that result in scientifically sound management decisions.

About Stillwater Sciences

Yantao Cui, PhD, has more than 20 years experience modeling sediment dynamics in natural and regulated rivers for engineer-ing design purposes and ecological management. Much of his work includes state-of-the-art numerical modeling of sediment processes that link land use and restoration activities with their effects on physical processes and habitat conditions of impor-tance to salmonids and other aquatic biota. His applied research projects involve investigation of sediment transport following dam removal, landslide or mass wasting, river bank erosion, effects of gravel extraction on fluvial geomorphic processes, fine sediment dynamics in gravel-bedded rivers, and the down-stream impacts of reservoir management. Dr. Cui is the author or co-author of more than 20 peer-reviewed journal articles and book chapters. He has been invited to speak at many national and international conferences as a recognized expert in sedi-ment transport and river mechanics and has led numerous analyses of potential impacts of dam removal on sediment.

Ethan Bell, MS, currently works in various capacities on several large-scale hydroelectric and watershed assessment projects along the west coast. His background in salmonid ecology al-lows him to provide technical expertise on endangered species consultation, hydroelectric relicensing, and impacts of dam removal. Mr. Bell was the lead on an analysis of the potential impacts on aquatic biota of removing dams on the Klamath River. Focal species for analysis included green sturgeon, Chi-nook salmon, coho salmon, steelhead, coastal cutthroat trout, and Pacific Lamprey.

Stephen Ralph, MS, has over twenty-nine years experience in natural resource management, concentrating on the effects of water and land use on freshwater and marine ecosystems. Prior to joining Stillwater Sciences to head the Washington operations in 2004, he worked for a variety of federal, state, tribal, city, and county governments engaged in resolving natural resource management decisions with environmental protection. On be-

half of the Elwha Tribe, and as part of the licensing proceedings, Mr. Ralph co-authored the 1986 motion to FERC for removal of the two dams on the Elwha River in order to restore the river and its native salmon runs. He worked collaboratively with the other stakeholders to gain their mutual support for dam re-moval, including consultation with the facility owner on options that would ensure that their power needs were met.

Peter Downs, PhD, CGeog, is the lead senior fluvial geomor-phologist at Stillwater Sciences with 20 years experience in the field of watershed-scale effects on sediment transport processes, channel morphological response and river restoration. He leads dam removal projects at Stillwater Sciences. He has technical expertise in both rapid and extensive geomorphic assessments, river restoration design and planning within an adaptive man-agement framework, post-project monitoring and evaluation, and integrated watershed planning. He is involved with many projects that aim to quantify sediment transport dynamics at the hillslope and channel scale in both natural and managed watersheds. He is the lead author of River Channel Management: towards sustainable catchment hydrosystems, the first textbook devoted specifically to the history and recent developments in management and restoration of river channels.

Maia Singer, PhD, has over 10 years experience in aquatic sci-ences and engineering spanning water quality, river restoration planning, ecology, and water treatment. Dr. Singer has particu-lar expertise in trace metals biogeochemistry, including the fate and transport of mercury, selenium, copper, zinc, and cyanide in river, wetland, and estuarine environments. Dr. Singer recently served as the technical lead for synthesis of the large body of existing information on water quality on the middle and lower Klamath River and the Klamath River Estuary, including an assessment of data gaps related to dam removal, water quality, and the potential impacts of climate change.

Key Stafffor Dam Removal Studies

Berkeley, CASabrina Simpsonsabrina@stillwatersci.com(510) 848-8098 x113

Davis, CAScott Wilcoxscott@stillwatersci.com(530) 756-7550 x230

Arcata, CADirk Pedersendirk@stillwatersci.com(707) 822-9607 x201

Santa Barbara, CADerek Boothdbooth@stillwatersci.com(206) 914-5031

Portland, ORJody Landojblando@stillwatersci.com(503) 267-9006

Santa Cruz, CAZooey Diggoryzooey@stillwatersci.com(831) 786-8969

Seattle, WASteve Ralphralph@stillwatersci.com(206) 632-0107

Contact Us

Dam Removal

For over a decade, Stillwater Sciences has been actively involved in advancing the science behind dam removal as a restoration approach, including contributions at national workshops on dam removal. By using modeling tools and site-specific field data, we are able to provide our clients with a comprehensive understanding of the short-term and long-term physical and biological impacts of dam removal at varying spatial scales with an un-biased, science-based perspective. This information is then used to determine likely impacts on valued native flora and fauna and the potential for downstream flood risk, and so allow stakeholders to understand the competing issues and benefits of dam removal. Our goal in these analyses is to provide the most cost-effective and ecologically-sound method for removing dams, specifically tackling the issue through the following ways:

• Numerical modeling: predicting downstream streambed conditions, associated physical/biological impacts, and evaluating different dam removal strategies• Physical modeling experiments: replicate site-specific field conditions and calibrate numerical models• Physical and biological monitoring: pre- and post-removal field studies, model calibration and validation, adaptive management• Planning and impact assessment: flood frequency, channel morphology and other geomorphic impacts; turbidity, nutrient loading, and other water quality impacts; fish passage, habitat quality and other biological impacts.

Marmot Dam RemovalPhoto courtesy of Don Ryan

The removal of Marmot Dam represented one of the first large-scale releases of dam-impounded sediment in the US, and thus raised numerous concerns about possible impacts on fish and aquatic species downstream of the dam. To assess these potential impacts, we evaluated geomorphic, sediment transport, and ecological conditions associated with approxi-mately 1 million cubic yards of sand and gravel being released once the dam was removed. We used numerical sediment transport models to predict changes in downstream bed elevation and assess potential impacts of the sediment release on fish habitat and water quality, as well as potential increases in flooding risk for downstream property owners associated with changes in the channel. The analyses permitted stake-holders to agree upon an ecologically and economically ac-ceptable dam removal alternative. Removal of Marmot Dam occurred in summer 2007.

Observations made one year after dam removal indicated that the sediment transport predictions made 8 years prior to dam re-moval were broadly accurate (see figure above), including the process of reservoir erosion and downstream channel aggradation, the low suspended sediment concentration associated with dam removal, and the quick restoration of fish passage.

Marmot Dam Removal, Sandy River, OregonC A S E S T U D Y : A S S E S S I N G E C O L O G I C A L E F F E C T S O F D A M R E M O VA L

R E L A T E D S E R V I C E S

Restoration Planning & ImplementationIncreasing urban development, threat-ened aquatic population levels, and ever-tightening budget constraints demand restoration efforts that are well designed and implemented. Stillwater Sciences employs a performance-led approach to process-based restoration planning and implementation. We identify the water-shed-specific context, the limiting physical and biological conditions, the biological performance criteria, a prioritized suite of measures best suited to restore natu-ral aquatic function, and a monitoring strategy to ensure the long-term achieve-ment of management goals. The result is a recommendation for restoration that is tailored to the specific needs of the watershed and site. Capitalizing on the diversity of our expertise and experience, our restoration projects incorporate water-shed-scale understanding of the physical and biological context, channel morphol-ogy, natural recovery, flow and sediment transport processes, habitat structure and diversity, and the specific needs of critical or endangered species.

Geomorphic MonitoringStillwater Sciences employs a cadre of highly-qualified geomorphologists from a variety of backgrounds who work closely with their colleagues and teaming partners to provide integrated biophysical and biogeochemical solutions to real-world issues in environmental manage-ment. We are highly experienced in moni-toring hillslope and channel geomorphic conditions for the purpose of helping our clients with project planning, character-izing site conditions (past, present, and future), and interdisciplinary problem-solving. Specific geomorphic monitoring services include:• Bed sediment transport monitoring: tracer rocks, scour cores, and scour chains• Channel geometry and gradient topo-graphic surveys• Field interpretation of channel condition • Analysis of channel sediment storage • Surface and subsurface sediment sam-pling• Fine sediment infiltration analyses• Stream flow monitoring• Historical analyses of channel change• Stream flow & sediment transport records analysis• Coastal sediment transport and deposi-tion analysis

With minimal funding and very limited existing field data, Stillwater Sciences conducted a preliminary study to evaluate potential sediment deposition in the Klamath River downstream of Iron Gate Dam if Iron Gate, Copco 1, Copco 2, and J.C. Boyle dams were removed. This study indicated that sediment deposi-tion downstream of the dams following dam removal will be minimal despite the estimated 20 million cubic yards of sediment deposit stored in the reservoirs.

This study was peer-reviewed by the nation’s top sediment transport experts, and the modeling results were recog-nized as credible. The result of this preliminary study for American Rivers helped to alleviate concerns of many stakeholders for flooding post-removal and provided the momentum for continued studies.

Stillwater Sciences was then contracted by the California

State Coastal Conservancy to conduct more detailed analyses based on addition-al data collected in the field. This study included examining sediment transport dynamics (i.e., channel responses, suspended sediment concentrations), po-tential impacts to key fish species, and water quality. The study confirmed the results of our preliminary study, concluding that there would be minimal sedi-ment deposition in the river following dam removal and thus, minimal increase in flooding risks. Analyzing more than 70 drawdown scenarios with multiple variables, such as different start dates, drawdown rates, and other inputs, we predicted suspended sediment concentrations following dam removal would be high upstream, but would quickly become diluted downstream as more tributar-ies join the mainstem. Our investigation also suggested that while there would be a short-term impact of dam removal, all focal fish species would recover in the long term. Our water quality analyses concluded little to no impact from sediment-associated nutrients or contaminants on riverine biota. Most long-term effects on temperature, nutrients, dissolved oxygen, pH, and turbidity will likely benefit native aquatic species.

Jointly with the University of California, Berkeley, and San Francisco State University, Stillwater Sciences was awarded a CALFED grant to examine geo-morphic responses to dam removal (and to gravel augmentation and river restoration) at a flume built at UC Berkeley’s Richmond Field Station. The flume experiments were designed to provide a rapid and economically viable way of testing for geomorphic impacts following river management decisions: riverine geomorphic investigations necessarily span large spatial and temporal scales, making it difficult and expensive to collect the field data necessary to fully evalu-ate such responses. With regards to dam removal, sediment management is fre-quently the most challenging concern in dam removal but there is little guidance available to resource managers. We experimented with two processes critical to evaluating the effects of dam removal: the linkage between sediment pulse texture and size and the magnitude and duration of impacts on downstream channel morphology, and physical parameters that control the infiltration dynamics of released fine sedi-ment into coarser downstream channel beds. For those rivers with beds composed primarily of non-cohesive sediments we found that (1) one-dimensional numerical modelling of sediment pulses can simulate reach-averaged transport and deposition over tens of kilometres, with sufficient certainty for managers to make informed decisions; (2) physical modeling of a coarse sediment pulse moving through an armoured pool-bar complex shows deposition in pool tails and along bar margins while maintaining channel complexity and pool depth similar to pre-pulse conditions; and (3) physical modeling and theoretical analysis show that fine sedi-ment will infiltrate into an immobile coarse channel bed to only a few median bed material particle diameters.

Iron Gate, Copco 1, Copco 2, and J.C. Boyle dams, Klam-ath River, California and Oregon

C A S E S T U D Y : F I S H A N D WA T E R Q U A L I T Y

Physical Modeling ExperimentsC A S E S T U D Y : F L U M E E X P E R I M E N T S

Learn more at www.stillwatersci.com

Sediment transport modeling conducted to evaluate removal of Saeltzer Dam on Clear Creek indicated minimal downstream impact. Although the ac-tive restoration projects (channel reconfiguration and gravel augmentation) implemented in conjunction with dam removal prevented a quantitative comparison of model prediction and field observation, it is obvious that dam removal resulted in minimal downstream impact as predicted in our sedi-ment transport evaluation.

Saeltzer Dam Removal, Clear Creek, CaliforniaC A S E S T U D Y : S E D I M E N T T R A N S P O R T E VA L U A T I O N

Stillwater Sciences is currently evaluating the sediment trans-port dynamics associated with the proposed removal of the 10-ft high Simkins Dam and the 34-ft high Bloede Dam on the Patapsco River, Maryland using DREAM-1 model. The study is ongoing, and is projected to be completed by the end of 2009. Simkins Dam will be removed in 2010, and Bloede Dam will be removed at a later date.

Simkins Dam and Bloede Dam, Patapsco River, MarylandC A S E S T U D Y : S E D I M E N T T R A N S P O R T D Y N A M I C S