Abstracts
Presentation Abstracts
(Alphabetically by Presenter*)
PRESENTATION TITLE, Restoring Ecosystem Processes and Resilience in River Systems
Dr. Luther Aadland, Minnesota Department of Natural Resources
River systems have been dramatically altered by land-use, climate and hydrologic changes, channelization, fragmentation by dam construction, and water pollution. For example, of Minnesota’s 84,705 miles of stream, an estimated 41,628 miles have been channelized, 2,968 miles have been impounded, while thousands of barrier dams and culverts block biotic migrations and recolonization. Similar changes globally have led to catastrophic declines in water quality, stream stability and biodiversity. Freshwater extinction rates far exceed those of other biomes. Biodiversity is an effective indicator of ecosystem health and resilience in river systems since it is dependent on parameters of hydrology, geomorphology, water quality, and connectivity. If allowed, river ecosystems can self-recover from many disturbances but are often unable to recover from past and ongoing human constraints. Many river projects have attempted to address symptomatic issues such as poor habitat or bank erosion with localized, structural solutions. Treatment of symptoms can be costly, temporary and, in some cases, hinder geomorphic and ecosystem processes or create new problems. In contrast, identification of underlying problems, relaxing human constraints to the degree possible, and reestablishing long-term geomorphic and biological processes can yield resilient, self-sustaining river ecosystems. Monitoring over broad spatial and temporal scales is necessary to establish success. Case examples will be presented to illustrate evaluated measures of ecosystem responses to river restoration and suggest strategies towards resilient river ecosystems.
PRESENTATION TITLE ,Has Stormwater Management Been Our Achilles Heel in River Management?
Dr. Bill Annable, Associate Professor of Civil and Environmental Engineering, University of Waterloo in Ontario, Canada
Stormwater management techniques have been employed to manage floodwaters since at least the era of the Roman Empire. Techniques have evolved into an intricate network of sewers, curb and gutters, ponds, swales and other infrastructure to route water away from developed areas to receiving water bodies with the preponderance being watercourses. Over the past century, impacts to watercourses from changing landuse practices have become more clearly realized and stormwater management strategies have been modified to address many of the hydrologic concerns. Such strategies have included: peak shaving, targeted velocities and durations to better accommodate fish migration and flow release rates at or below critical shear stress thresholds of bed and bank media to reduce channel erosion have become common place.
The current and past strategies to manage altered flows have afforded little attention to managing the continuum of bed material transport which represents half of Lane’s balance in maintaining channel stability for any given watercourse. The presence of oversized channels, oversized infrastructure (e.g. culverts), sediment detention ponds (including forebays), on- and off-line stormwater management ponds, enhanced routing, bridge spans to convey regulatory flood flows rather than spans to maintain riparian corridor stability further exacerbate the sediment transport continuum – Stoke’s Law remains valid and channels continue to degrade and exacerbate ongoing maintenance. This becomes a particularly challenging obstacle when a proponent may be contemplating either a river restoration or rehabilitation initiative. With both flow and sediment regimes irrevocably altered from landuse change, rehabilitation offers greater opportunities for design success, however, this approach in many cases may need to alter both the historical geomorphic alignment and ecological targets of a given watercourse.
If proponent’s expectations are to undertake river restoration approaches to perpetuate historical channel alignments and ecological targets, stormwater management strategies need to be notably reconstituted to include the continuum of bed material transport. Fortunately, low impact development (LID) initiatives are beginning to take hold in North America which may be the first step along this pathway continuum. It is an axiomatic notion in the fields of surface water chemistry and contaminant hydrogeology that the most effective ways to mitigate contamination are to first remove the sources of the contamination and then address the residual plume effects. A similar analogy should apply in stormwater management where rain harvesters could be installed in combination with depressional storage at the lot scale of all new (and eventually matured) developments which would remove the first one to two inches of precipitation while not interrupting the continuum of upland washload transport. Stream and river corridors could then be configured (notably larger floodplains) to accommodate the lower frequency higher magnitude flood events while maintaining sediment continuity. Such approaches would further decrease the need for other infrastructure (such as ponds) within a development envelop offsetting costs of LID investments. This presentation will summarize many of the pitfalls in current stormwater best management practices, effects upon river channels (which are applicable to urban and rural watercourses) and mitigative strategies to re-establish the bed material continuum.
PRESENTATION TITLE, The Growing & Evolving Benefits of Stream Restoration – From Resiliency to Stormwater BMP – How Will the Industry Continue to Adapt?
George Athanasakes, P.E. Stantec Consulting Services Inc.
Stream restoration continues to grow in popularity across the United States. The very practice of stream restoration relies on adaptive management to ultimately implement projects and set streams on the trajectory of sustainability. Interestingly, the profession in general and the funding sources used to pay for stream restoration are also undergoing an adaptive management process. Historically mitigation and/or fisheries enhancement were the key drivers funding stream restoration projects. Now in many areas across the US, the need for resilient communities and water quality enhancements through the TMDL program have resulted in significant funding sources for stream restoration projects.
This talk will explore the ever-evolving field of stream restoration and the adaptive management that the profession is currently under from multiple perspectives. Specifically, the evolution of funding sources for restoration implementation will be discussed and examples of key drivers for funding stream restoration in different parts of the country will be explored as well as the applicability of these funding approaches to other areas. Specific examples of the benefits of stream restoration from a resiliency and TMDL reduction perspective will be provided. The adaptive management of the profession will also be discussed. Are we evolving to a profession that will be licensed or will we be continuing on the current path? Are schools of thought for restoration converging or diverging? How are the benefits of stream restoration evolving? These questions will be explored from a practitioner’s perspective.
PRESENTATION TITLE, The Yellow River Initiative - An Introduction to the Kankakee River Problem and Plan
Bob Barr, Indiana University-Purdue University Indianapolis. Siavash Beik, Christopher B. Burke Engineering Inc.
The Kankakee River Basin is one of the most extensively modified watersheds in Indiana. Since 1977 the Kankakee River Basin Commission (KRBC) has struggled to balance drainage with sediment loss, flooding, and a long, increasing list of competing uses. The never-ending cycle of dredging and clearing the river has become increasingly unsustainable, and the politics of an interstate river basin more difficult. The KRBC has never tried to manage the basin in a vacuum; the Kankakee may be the most studied watershed in Indiana, but the questions have changed. For the last two decades, a growing body of work has demonstrated that rivers need to be managed as systems. The “patch here and dredge there” strategy doesn’t work. It simply moves the problem. The KRBC has come to realize this paradigm shift. They have fought with budgets and eroding sand dunes longer than anyone, and there is more sand than money. The KRBC has now asked the question: “is there a better way to manage this river system?” There are no easy answers, but the KRBC with the help and support of the Indiana Silver Jackets is trying to come up with ways to better manage the Kankakee River basin. In this presentation, we will discuss the most recent efforts of the KRBC to lay out and initiate, with the help of Indiana Silver Jackets, a new path to better understand and address the challenges facing the Kankakee River system – the Everglades of the North.
PRESENTATION TITLE, River channel responses to large increases in flows and sediment supply
Dr. Patrick Belmont, Associate Professor Utah State University
Alluvial river channels adjust their width, depth, and slope over time in order to convey the amount of water and sediment supplied from the watershed. Rivers throughout Minnesota have experienced profound changes in flow and sediment supply over the past few decades and are likely to experience further changes in the future. How have rivers responded to these large changes? Why do we observe different responses in different regions? What does this all mean for river policy, management and restoration? We document that flows have increased considerably in many parts of the state due to changes in both climate and artificial drainage. Next, we show that these increases in flow have very different implications in terms of sediment supply throughout the state because sediment rating curves (discharge-suspended sediment relationships) vary considerably throughout Minnesota. We find that the general shape and the steepness of these relationships is primarily dictated by geology and geomorphic history, while vertical offset of the relationships and suspended sediment concentrations of low flows are influenced by land use. This finding should help us prioritize locations where management and restoration actions can do the most good in terms of sediment reductions. Lastly, we document very distinct responses to the increases in flow and sediment supply in different parts of the state. For example, the Le Sueur River contains a very distinct slope break (knick zone) approximately 40 km from the mouth of the river. Above knick zone is low gradient, passively meandering channel. Within the knick zone the channel is relatively high gradient, actively meandering and rapidly incising. Thus, the knick zone reach has much stronger response to the increases in flow. Similarly, the Minnesota River between Mankato and Jordan is aggradational and highly dynamic with rapid meander migration rates, frequent channel cutoffs, and has responded to increased flow and sediment supply by increasing channel width considerably. In stark contrast, the Minnesota River between Jordan to Fort Snelling is far less dynamic, with passive meanders and few natural cutoffs because it has a relatively small supply of sediment. The Root River in south-eastern Minnesota has similarly distinct river reaches, but the legacy effects of land use in the watershed manifest themselves in very different ways. Recognizing these differences throughout Minnesota in the morphology of rivers and their responses to increased flow and sediment supply allows us to establish more feasible restoration goals. Some geomorphic settings require that we design for active, dynamic channels. Stable channel design is more appropriate in other settings.
PRESENTATION TITLE, Streams without Biology: How Physics Inadvertently Usurped River Restoration.
Dr. Janine Castro, Project Leader, US Fish and Wildlife Service, Vancouver, Washington
The foundations of river restoration science rest comfortably in the fields of geology, hydrology, and engineering. Lane’s stream balance equation from the mid-1950s taught us that there is a dynamic equilibrium between the amount of stream flow, the slope of the channel, and the amount and caliber of sediment. The Manning’s equation, circa 1890, still influences most stream restoration projects designed today. Inherent in that famous equation are the variables of slope and hydraulic radius, and the ever-confounding roughness coefficient – n. Biology, while completely absent in the stream balance equation, makes a cameo appearance in the Manning’s equation buried in the roughness factor. Arguably, two of the most influential equations that have shaped contemporary river restoration design left out the power of biology. This would not be a problem if we were designing and implementing river restoration in a Precambrian world -- a world where green algae and fungi are the major biological players -- but in today’s environment, biology cannot be ignored.
This talk will provide an overview of, and underpinning science for, the Stream Evolution Triangle (SET) in which biology is included on an equal basis with geology and hydrology as a driver of stream morphology. The SET broadly integrates concepts geology, hydrology, and biology, and includes improved understanding of potential morphological “stream states” at the reach scale following both natural and anthropogenic disturbances. Rather than a deterministic approach, the SET recognizes that similar events can result in various stream morphologies, while dissimilar events can result in a single, dominant stream morphology. The probability of a particular future state is strongly predicated by the relative influence of geology, hydrology, and biology. The SET assumes dynamic morphological evolution through time and recognizes variable rates of change for both spatial and temporal scales, along with numerous potential trajectories.
Having introduced the SET, evidence from completed projects will be presented as case studies for application in innovative stream restoration. Potential utility of the SET in stream restoration planning and design stems from improved understanding and explanation of morphological “stream states”, explicitly including the role of biology, which provides insights into appropriate restoration strategies to counter adverse impacts from past disturbance, while building future resilience.
PRESENTATION TITLE, Applied Research Efforts to Improve the Design, Implementation and Management of Ecological Restoration in North Carolina.
Dr. Barbara Doll, North Carolina State University.
Stream restoration is “big business” with over a billion dollars spent annually on restoration projects across the US. North Carolina is recognized as a national leader in stream restoration innovation, design and implementation. The rise of restoration in N.C. was in part due to the leadership, creativity and innovation afforded by the formation of the NC State University Stream Restoration Program (SRP) in the late 90’s. A partnership of the Biological & Agricultural Engineering Department and NC Sea Grant, the SRP is a team of faculty, staff, and students working to improve water quality and aquatic ecology through research, demonstration projects, and education. Following two decades of developing, testing, demonstrating and evaluating natural channel design focused restoration practices, the SRP now focuses heavily on evaluating the ecological performance and functional uplift and the metrics and tools for gauging these outcomes. The SRP also offers a series of River Course workshops with 4-6 short courses a year attended by more than 200 restoration professionals and a biennial stream conference, EcoStream, which attracts 350-400 participants. Since inception, the SRP has provided training and education to more than 6000 professionals in stream assessment, design, construction, modeling and monitoring.
Commonly stated goals for stream restoration include enhancing water quality, improving aquatic habitat, stabilizing stream banks, establishing native riparian vegetation and enhancing floodplain function. Many funding agencies have realized the need to document and quantify functional performance of restoration efforts. The SRP has partnered with state and federal agencies, local governments and non-profit organizations to develop research projects focused on evaluating the ecological benefits, including water quality for restoration efforts and to identify new and innovative practices to maximize these ecological benefits. This presentation will feature several of these efforts.
SRP assessed 157 restored, impaired and reference streams during 2006-2012 using several rapid assessment tools. Macroinvertebrates were collected from 85 of the restored streams and watershed assessment was conducted for a selection of streams. Morphological design data and site-specific landscape factors were also compiled for 79 of the restored streams. Statistical analysis revealed that macroinvertebrate metrics correlated with stream assessment variables and as expected, watershed condition variables improved correlation in most cases. In addition, restored streams were found to have morphologic conditions similar to reference streams, but exhibit greater variability in aquatic habitat and bedform. Larger (wider) streams in steeper valleys with larger substrate and un-developed watersheds have higher numbers of pollution intolerant EPT taxa. Also, greater floodplain widths correlate with higher EPT taxa.
In partnership with the NC Division of Mitigation Services, NC’s in-lieu fee mitigation program, and the Environmental Defense Fund, SRP is currently evaluating functional uplift and physical and morphological adjustment of stream restoration projects in the Piedmont region of NC. In addition, to assist the state’s Department of Environmental Quality in developing proposed nutrient crediting protocols for stream restoration projects, the SRP has conducted data collection, analysis and technical advice to evaluate the three mechanisms of nutrient reduction currently being considered (i.e. streambank erosion, hyporheic exchange and increased floodplain connectivity) in order to develop nutrient crediting criteria that are based on sound science.
PRESENTATION TITLE, Stream Channel Succession and Sediment Dynamics: Black Vermillion River, KS
Dr. Tim Keane, Principal Investigator Kansas State University
The Black Vermillion River drains approximately 410 square miles in northeastern Kansas. The drainage basin of the Black Vermillion River lies within Ecoregion 47: Western Corn Belt Plains. Surface materials are dominated by alluvium and glacial drift/till. Conversion from native, warm-season tallgrass prairie to agricultural production caused significant impacts to the river channel and riparian landscape. Major channelization shortened the river by nearly 16 miles from pre-settlement dimensions; this shortening combined with the construction of numerous flow-through structures/dams have produced dramatic changes in discharge and sediment dynamics.
In 2007, nine monitored stream reaches were established within three main tributaries of the Black Vermillion River of northeast Kansas. Each reach was surveyed and assessed for channel stability. Subsequent surveys (2008-2010) were conducted along with monitoring of streambank erosion, bed scour, and sediment size/distribution shifts. Surveys allowed for geomorphic characterization, quantification of stability, and identification of stream successional sequence. This work allowed correlation of stream ‘state’ and in-channel sediment contributions, as well as prediction of future erosion rates based upon progression of stream succession.
This presentation recounts our predictions of channel succession on the Black Vermillion River and the coincident sediment yield associated with establishment of a stable channel form at current bed elevations. Calculations assume that a stable channel and floodplain at current bed elevation is the most acceptable design solution in this tillage agriculture dominated landscape. Use of natural channel design parameters allows for the prediction of stable channel form and sediment yields associated with channel succession. Our measured erosion rates and basin-specific bank erosion curves (Sass and Keane, 2012) allow prediction of the time frame for stream channel succession. Such understanding is critical in determining not only how but when to most effectively mitigate the myriad of instability consequences.
This work was supported by USDA CREES 406 Integrated Program (Grant#KS600399).
PRESENTATION TITLE, Trick or Treat: Does Natural Channel Design Work to Improve Stream Ecological Function?
Matt Kondratieff , Colorado Parks and Wildlife
Rivers that depart from natural channel forms can limit ecological recovery of aquatic ecosystems and ultimately degrade habitat. Departures include channelization, loss of floodplain connectivity, removal of wood, habitat fragmentation, and altered hydraulic conditions. Monitoring results from fish populations occupying impaired rivers have shown that recovery may require many decades before populations begin to stabilize and even longer before populations show positive signs of recovery. Fish populations occupying degraded river systems may continue to decline without active restoration intervention, such as application of Natural Channel Design (NCD). Uncertainty exists whether application of NCD result in improvements to ecological function that can last over time. In Colorado and Montana, long-term monitoring of NCD projects provide evidence that stream ecological functions have improved, such as increases in fish biomass, density, and species diversity. In addition, NCD project monitoring spanning up to 27 years have shown sustained improvement in fish populations over time. Restoration of full ecological function as compared to reference quality sites has been achieved in NCD project site in Montana but not Colorado
PRESENTATION TITLE, Stream Restoration: Does Restoring Structure Lead to Function?
Dr. Sara McMillan, Associate Professor, Agricultural & Biological Engineering
Purdue University
Efforts are underway globally to improve water quality and other ecosystem services in watersheds impacted by urbanization and agricultural production. Excess nutrients (i.e., nitrogen and phosphorus) create eutrophic conditions that threaten water supply for human consumption as well as ecological health. It has long been recognized that the interfaces between terrestrial and aquatic ecosystems are locations where nutrient processing and removal is maximized. However, these river-floodplain systems are the same environments that are the most severely degraded by human development, including piped water conveyance, river network modifications for flood control, agricultural production and infrastructure placement. Competing uses for land necessitate innovative solutions that maximize biophysical processes to reduce nutrient export. Stream and riparian restoration is one strategy that seeks to do so. Practices enhance channel stability and geomorphic complexity by reconstructing stream channels, planting riparian vegetation and connecting floodplains. The assumption is that the structural changes to mimic natural systems will allow the development of functional equivalencies as well. Our research shows that restoring stream-floodplain connectivity results in greater inputs of sediments and nutrients with subsequent impacts on nutrient biogeochemistry. This was particularly evident downstream of impaired reaches, which highlights the need to optimize placement of practices for maximum impact. We also show that time lags exist in recovery of ecosystem function following stream restoration, particularly related to biologically driven nutrient retention. This is critical for monitoring programs aimed at measuring success and ensuring sufficient time for restoration practices to achieve desired goals.
PRESENTATION TITLE, Stream and watershed restoration: guidance for restoring riverine processes and fish habitat
Dr. Philip Roni, Principal Scientist , Cramer Fish Sciences
Billions of dollars are spent annually in North America and Europe to restore rivers and improve fish habitat. Unfortunately, many of these well-intentioned efforts fail to meet their objectives because they ignore watershed processes or do not follow key steps needed to adequately plan, implement and evaluate restoration. Here I provide an overview of the eight key steps needed to plan restoration, assess watershed conditions, identify restoration actions, select and prioritize restoration techniques and monitor and evaluate their success. I provide examples of successful methods, analyses or models used to address each of these key steps. Before assessing conditions or identifying restoration opportunities, it is important to have a clearly defined restoration or recovery goal. Assessment of watershed processes and habitat conditions should include assessment of potential and current rates or conditions and identify the causes of habitat degradation and loss. In selecting appropriate restoration actions, it is important to be aware of whether the actions restore underlying processes or simply improve habitat as well as the longevity, likelihood of success, and whether they ameliorate the impacts of climate change. Several approaches exist for prioritizing restoration actions at a regional, watershed, and reach scale. The most transparent and repeatable approach for prioritizing restoration projects is multi-criteria decision analysis (scoring system) that can incorporate quantitative and qualitative information including scientific and socio-economic data. Monitoring of restoration projects needs to be designed well before the projects are implemented and have clear testable hypotheses and a rigorous study design. Unfortunately, many monitoring programs fail not because of inadequate design, but because of poor implementation, quality control and management – all factors that can usually be overcome by diligent project management. The steps and considerations outlined in this presentation, if followed, should ensure that restoration actions are effective at restoring watershed processes and habitat.
PRESENTATION TITLE, Restoring Ecological & Geomorphic Function on the Heartrock Ranch, Idaho
Dr. Dave Rosgen, Wildland Hydrology
A large-scale restoration following the Natural Channel Design approach was implemented in 2011 near Sun Valley, Idaho, with primary goals of establishing cold-water fisheries and enhancing river stability (i.e., transporting sediment and streamflows) and hydrological connectivity (longitudinal, lateral, vertical, and temporal). Assessments related to both ecological and geomorphic functioning at multiple spatial scales were conducted to direct the restoration by identifying limiting factors for various species and their habitats, including large mammals, eagles, heron, waterfowl, songbirds, and aquatic organisms. A downstream reference reach on Willow Creek was used to represent the physical and biological potential of the impaired river system.
Assessment results indicate that heavy, season-long livestock grazing, poor irrigation practices, and direct channel impacts were responsible for numerous impairments, including:
Monitoring results show that average stream discharge increased even during low precipitation years, residual pool depth increased (< 0.18 m to > 0.9 m), spawning substrates increased in size (0.11 mm to 19 mm), and estimated egg-to-fry trout survival increased from less than 20% to more 90% based on the Fredle indices. Invertebrate indices of restoration effectiveness were “positive”, and fish diversity increased from three to seven species in the restored spring creeks, which matched species diversity in the post-restoration reference reach. For the two restored streams, redd counts increased dramatically (7 to 161 and from 17 to 143). Likewise, the electrofishing catch-per-unit-effort for wild trout increased dramatically (0.013 to 1.166 trout/m and 0.029 to 0.222 trout/m) for the two spring creeks as part of the larger community-level response. According to ranch accounts, the restoration and aquifer recharge approach increased hay production and reduced labor needs by converting flood irrigation to sub-irrigation.
PRESENTATION TITLE, Sediment Sources, Baseline Sediment-Transport Rates and the Effectiveness of Restoration Measures for Reducing Loads to Receiving Waters
Dr. Andrew Simon, Cardno
The impact of erosion, transport and delivery of sediment to receiving-water bodies is the focus of worldwide attention in efforts to protect drinking water, aquatic and marine resources, and maintain reservoir capacity for water supply, flood control and power generation. To adopt effective sediment-control measures to protect receiving waters, it is not sufficient to only know the magnitude of the sediment load, but also the major contributing sources. Potential sediment sources may include: uplands (from overland flow and mass movements) including gullies, dirt roads, fields and channels (bed and banks). There has long been an overemphasis on the role of uplands and fields on sediment erosion and delivery at the expense of channel processes (e.g. Chesapeake Bay, the Great Barrier Reef). This is largely due to institutional inertia that produces a reliance on watershed models to predict sediment loads, notwithstanding that these models cannot account for one of the most important sources today; streambanks.
A series of studies from the Chesapeake Bay Watershed show that streambank sediments may account for 47-95% (mean of 71%) of sediment yields. In contrast, based on watershed modeling, EPA suggests that only 30% is derived from streambanks. For example, in southern Queensland, Australia, watershed modeling showed that 60% of the suspended load delivered to the Great Barrier Reef from the Burnett River was emanating from uplands, while just 8% of the 2.76 million tonnes/y was generated from streambanks. A subsequent, detailed study of streambank erosion, however, showed by both empirical and modeling approaches that streambank erosion accounted for between 44% and 73% of the average, annual-suspended load.
The locus of sediment erosion has shifted from the uplands to the channel systems as soil-conservation measures improved and rivers adjusted to influxes of agricultural sediment and other anthropogenic activities. These periods of instability are marked by increases in sediment-transport rates. Contributions from channel sources, particularly streambanks can typically be in excess of 50% of the total suspended-sediment load. Transport rates from stable or re-equilibrated systems, however, are used to determine baseline or “reference” transport rates. Examples from various ecoregions are provided and range over several orders of magnitude.
It is, therefore, critical to use the appropriate analytic tools if one hopes to be able to accurately determine magnitudes of sediment delivery from various sources, and to determine effective sediment-reduction strategies. For streambanks, the dynamic version of the Bank-Stability and Toe-Erosion Model (BSTEM) is used to simulate bank erosion over extended flow periods. Used in combination with observations of the longitudinal extent of failing banks, unit loadings (per m of channel length) are extrapolated to determine bank-generated sediment loads. Predictions of important load reductions along with the effectiveness and cost-effectiveness of a range of restoration measures slope are quantified by comparing erosion rates for the same flow series under “existing” and various restoration strategies. These may include direct modification or protection of banks, riparian plantings, changes in flow regime or grade control. Examples are provided from the U.S., Australia and New Zealand.
PRESENTATION TITLE, Adaptive Management: Using Geomorphic Stream Stage and Transition and Departure Conditions to Plan and Generate Restoration
Dr. W. Barry Southerland, National W2Q Fluvial Geomorphologist
Understanding stage, transition, and channel evolution is a fundamental necessity in developing restoration practices considered to be natural channel restoration. Developing alternative restoration that operates within the natural range of physical variability based on models or analytical equations alone are at high risk of not meeting physical stability, biological objectives and diversity. Avoiding visits to the field involving critical measures of dimension pattern, profile and sediment studies to identify stable morphological stream types and the departure therein will inevitably have consequences. Adaptive management in river restoration is most completely served with this planning paradigm intact. Validation of the current stable analog, aka reference reach, in the similar hydrophysiographic region and fluvial landscape-valley type is essential.
Throughout the Pacific Northwest and the Intermountain West structural practices instead of geomorphic system and channel evolution based designs are still popular. In some areas in the West, such as the Pacific Northwest a structure name has driven design instead of natural stable dimensions, pattern, and profile associated with the type and distribution of sediment load. In many instances success and even objectives have become a moving target instead of identifying and serving the principle objectives stated on permits and funding documentation. Impacts on water quality are potentially a concern.
This paper discusses both river restoration successes and failures due to the consequences of not completing an analysis of stage, transition, channel evolution and departure analysis. In some instances extreme wood structures have been designed without the consideration of riparian vegetation plan and practice. In other instances, even when bank stability was stated as a design objective, extreme lateral recession occurred next to structures and it was acceptable because it was considered a natural process. In other instances, lack of consideration of the socio-economic landscape was not considered in the planning process. Channel evolution, stage of adjustments, and identification of a stable morphological geomorphic stream type within the given hydrophysiographic region with valley landscape types are essential to base line adaptive management and riparian ecological stage and transition. These are pre-requisites for appropriate and robust natural channel restoration.
PRESENTATION TITLE, Land Use Change impact on Channels
DR. Sandy Verry, Ellen River Partnership; Research Hydrologist Emeritus,
USDA Forest Service
River width is determined by watershed area, climate and stream type; but changes in land use can cause a doubling of channel size along with a 400% increase in sediment yield as channels evolve. The root causes are an increase in channel discharge resulting from a desynchronization of snowmelt, soil compaction during wet weather logging and changes in watershed roughness largely caused by the loss of mature trees. Channel discharge increases 2 to 3 times over the 1 to 50-year frequency range. Compared with land rebound from glacial melt, land use channel changes occur in mostly a 50-year time span rather than thousands of years and are in the range of 1-ft vertical and 1-ft horizontal per year compared with 1- or 2-mm per year for land rebound adjustments. More frequent and larger storms caused by climate change may also cause channel adjustments especially in narrow valleys with limited floodplains where bridges are a better long-term bet than culverts.
PRESENTATION TITLE, Regional Sediment Data and Regional Curves: Increasing Confidence in Designs through Competence, Capacity and Support
Alan Walker, Streamwalker Consulting, LLC and Consulting Agent/Project Manager, Resource Institute, Inc.
Excess sediment in the stream corridor contributes to many issues in the watershed including public water supplies, flooding, aquatic habitat, and impoundments/receiving waters. Raising the awareness of the amount of sediment entering the stream systems from stream bank erosion is not only a water quality issue, but a key component in the assessment and proposed solutions to address this natural resource concern.
Field practitioners of natural channel design must incorporate two major data resources into the process of assessment and design.
Field practitioners need local hydro-physiographic data to correlate regional curve data for use in validating bankfull and sediment data as well as channel competence and capacity for design alternatives evaluation. Collecting and analyzing sediment data using USGS field techniques allows the development of regional sediment curves. The sediment curves in conjunction with regional curve discharge data can be used in the development of dimensionless sediment curve data for use in assessment and design. RIVERMorph™ software is an excellent tool for incorporating this data and evaluating existing cross sections for competence and capacity as well as proposed cross sections. Utilizing regional curve data and sediment data to design appropriate width/depth ratios are vital components of successful stream restoration and/or stabilization projects.
Dr. Luther Aadland, Minnesota Department of Natural Resources
River systems have been dramatically altered by land-use, climate and hydrologic changes, channelization, fragmentation by dam construction, and water pollution. For example, of Minnesota’s 84,705 miles of stream, an estimated 41,628 miles have been channelized, 2,968 miles have been impounded, while thousands of barrier dams and culverts block biotic migrations and recolonization. Similar changes globally have led to catastrophic declines in water quality, stream stability and biodiversity. Freshwater extinction rates far exceed those of other biomes. Biodiversity is an effective indicator of ecosystem health and resilience in river systems since it is dependent on parameters of hydrology, geomorphology, water quality, and connectivity. If allowed, river ecosystems can self-recover from many disturbances but are often unable to recover from past and ongoing human constraints. Many river projects have attempted to address symptomatic issues such as poor habitat or bank erosion with localized, structural solutions. Treatment of symptoms can be costly, temporary and, in some cases, hinder geomorphic and ecosystem processes or create new problems. In contrast, identification of underlying problems, relaxing human constraints to the degree possible, and reestablishing long-term geomorphic and biological processes can yield resilient, self-sustaining river ecosystems. Monitoring over broad spatial and temporal scales is necessary to establish success. Case examples will be presented to illustrate evaluated measures of ecosystem responses to river restoration and suggest strategies towards resilient river ecosystems.
PRESENTATION TITLE ,Has Stormwater Management Been Our Achilles Heel in River Management?
Dr. Bill Annable, Associate Professor of Civil and Environmental Engineering, University of Waterloo in Ontario, Canada
Stormwater management techniques have been employed to manage floodwaters since at least the era of the Roman Empire. Techniques have evolved into an intricate network of sewers, curb and gutters, ponds, swales and other infrastructure to route water away from developed areas to receiving water bodies with the preponderance being watercourses. Over the past century, impacts to watercourses from changing landuse practices have become more clearly realized and stormwater management strategies have been modified to address many of the hydrologic concerns. Such strategies have included: peak shaving, targeted velocities and durations to better accommodate fish migration and flow release rates at or below critical shear stress thresholds of bed and bank media to reduce channel erosion have become common place.
The current and past strategies to manage altered flows have afforded little attention to managing the continuum of bed material transport which represents half of Lane’s balance in maintaining channel stability for any given watercourse. The presence of oversized channels, oversized infrastructure (e.g. culverts), sediment detention ponds (including forebays), on- and off-line stormwater management ponds, enhanced routing, bridge spans to convey regulatory flood flows rather than spans to maintain riparian corridor stability further exacerbate the sediment transport continuum – Stoke’s Law remains valid and channels continue to degrade and exacerbate ongoing maintenance. This becomes a particularly challenging obstacle when a proponent may be contemplating either a river restoration or rehabilitation initiative. With both flow and sediment regimes irrevocably altered from landuse change, rehabilitation offers greater opportunities for design success, however, this approach in many cases may need to alter both the historical geomorphic alignment and ecological targets of a given watercourse.
If proponent’s expectations are to undertake river restoration approaches to perpetuate historical channel alignments and ecological targets, stormwater management strategies need to be notably reconstituted to include the continuum of bed material transport. Fortunately, low impact development (LID) initiatives are beginning to take hold in North America which may be the first step along this pathway continuum. It is an axiomatic notion in the fields of surface water chemistry and contaminant hydrogeology that the most effective ways to mitigate contamination are to first remove the sources of the contamination and then address the residual plume effects. A similar analogy should apply in stormwater management where rain harvesters could be installed in combination with depressional storage at the lot scale of all new (and eventually matured) developments which would remove the first one to two inches of precipitation while not interrupting the continuum of upland washload transport. Stream and river corridors could then be configured (notably larger floodplains) to accommodate the lower frequency higher magnitude flood events while maintaining sediment continuity. Such approaches would further decrease the need for other infrastructure (such as ponds) within a development envelop offsetting costs of LID investments. This presentation will summarize many of the pitfalls in current stormwater best management practices, effects upon river channels (which are applicable to urban and rural watercourses) and mitigative strategies to re-establish the bed material continuum.
PRESENTATION TITLE, The Growing & Evolving Benefits of Stream Restoration – From Resiliency to Stormwater BMP – How Will the Industry Continue to Adapt?
George Athanasakes, P.E. Stantec Consulting Services Inc.
Stream restoration continues to grow in popularity across the United States. The very practice of stream restoration relies on adaptive management to ultimately implement projects and set streams on the trajectory of sustainability. Interestingly, the profession in general and the funding sources used to pay for stream restoration are also undergoing an adaptive management process. Historically mitigation and/or fisheries enhancement were the key drivers funding stream restoration projects. Now in many areas across the US, the need for resilient communities and water quality enhancements through the TMDL program have resulted in significant funding sources for stream restoration projects.
This talk will explore the ever-evolving field of stream restoration and the adaptive management that the profession is currently under from multiple perspectives. Specifically, the evolution of funding sources for restoration implementation will be discussed and examples of key drivers for funding stream restoration in different parts of the country will be explored as well as the applicability of these funding approaches to other areas. Specific examples of the benefits of stream restoration from a resiliency and TMDL reduction perspective will be provided. The adaptive management of the profession will also be discussed. Are we evolving to a profession that will be licensed or will we be continuing on the current path? Are schools of thought for restoration converging or diverging? How are the benefits of stream restoration evolving? These questions will be explored from a practitioner’s perspective.
PRESENTATION TITLE, The Yellow River Initiative - An Introduction to the Kankakee River Problem and Plan
Bob Barr, Indiana University-Purdue University Indianapolis. Siavash Beik, Christopher B. Burke Engineering Inc.
The Kankakee River Basin is one of the most extensively modified watersheds in Indiana. Since 1977 the Kankakee River Basin Commission (KRBC) has struggled to balance drainage with sediment loss, flooding, and a long, increasing list of competing uses. The never-ending cycle of dredging and clearing the river has become increasingly unsustainable, and the politics of an interstate river basin more difficult. The KRBC has never tried to manage the basin in a vacuum; the Kankakee may be the most studied watershed in Indiana, but the questions have changed. For the last two decades, a growing body of work has demonstrated that rivers need to be managed as systems. The “patch here and dredge there” strategy doesn’t work. It simply moves the problem. The KRBC has come to realize this paradigm shift. They have fought with budgets and eroding sand dunes longer than anyone, and there is more sand than money. The KRBC has now asked the question: “is there a better way to manage this river system?” There are no easy answers, but the KRBC with the help and support of the Indiana Silver Jackets is trying to come up with ways to better manage the Kankakee River basin. In this presentation, we will discuss the most recent efforts of the KRBC to lay out and initiate, with the help of Indiana Silver Jackets, a new path to better understand and address the challenges facing the Kankakee River system – the Everglades of the North.
PRESENTATION TITLE, River channel responses to large increases in flows and sediment supply
Dr. Patrick Belmont, Associate Professor Utah State University
Alluvial river channels adjust their width, depth, and slope over time in order to convey the amount of water and sediment supplied from the watershed. Rivers throughout Minnesota have experienced profound changes in flow and sediment supply over the past few decades and are likely to experience further changes in the future. How have rivers responded to these large changes? Why do we observe different responses in different regions? What does this all mean for river policy, management and restoration? We document that flows have increased considerably in many parts of the state due to changes in both climate and artificial drainage. Next, we show that these increases in flow have very different implications in terms of sediment supply throughout the state because sediment rating curves (discharge-suspended sediment relationships) vary considerably throughout Minnesota. We find that the general shape and the steepness of these relationships is primarily dictated by geology and geomorphic history, while vertical offset of the relationships and suspended sediment concentrations of low flows are influenced by land use. This finding should help us prioritize locations where management and restoration actions can do the most good in terms of sediment reductions. Lastly, we document very distinct responses to the increases in flow and sediment supply in different parts of the state. For example, the Le Sueur River contains a very distinct slope break (knick zone) approximately 40 km from the mouth of the river. Above knick zone is low gradient, passively meandering channel. Within the knick zone the channel is relatively high gradient, actively meandering and rapidly incising. Thus, the knick zone reach has much stronger response to the increases in flow. Similarly, the Minnesota River between Mankato and Jordan is aggradational and highly dynamic with rapid meander migration rates, frequent channel cutoffs, and has responded to increased flow and sediment supply by increasing channel width considerably. In stark contrast, the Minnesota River between Jordan to Fort Snelling is far less dynamic, with passive meanders and few natural cutoffs because it has a relatively small supply of sediment. The Root River in south-eastern Minnesota has similarly distinct river reaches, but the legacy effects of land use in the watershed manifest themselves in very different ways. Recognizing these differences throughout Minnesota in the morphology of rivers and their responses to increased flow and sediment supply allows us to establish more feasible restoration goals. Some geomorphic settings require that we design for active, dynamic channels. Stable channel design is more appropriate in other settings.
PRESENTATION TITLE, Streams without Biology: How Physics Inadvertently Usurped River Restoration.
Dr. Janine Castro, Project Leader, US Fish and Wildlife Service, Vancouver, Washington
The foundations of river restoration science rest comfortably in the fields of geology, hydrology, and engineering. Lane’s stream balance equation from the mid-1950s taught us that there is a dynamic equilibrium between the amount of stream flow, the slope of the channel, and the amount and caliber of sediment. The Manning’s equation, circa 1890, still influences most stream restoration projects designed today. Inherent in that famous equation are the variables of slope and hydraulic radius, and the ever-confounding roughness coefficient – n. Biology, while completely absent in the stream balance equation, makes a cameo appearance in the Manning’s equation buried in the roughness factor. Arguably, two of the most influential equations that have shaped contemporary river restoration design left out the power of biology. This would not be a problem if we were designing and implementing river restoration in a Precambrian world -- a world where green algae and fungi are the major biological players -- but in today’s environment, biology cannot be ignored.
This talk will provide an overview of, and underpinning science for, the Stream Evolution Triangle (SET) in which biology is included on an equal basis with geology and hydrology as a driver of stream morphology. The SET broadly integrates concepts geology, hydrology, and biology, and includes improved understanding of potential morphological “stream states” at the reach scale following both natural and anthropogenic disturbances. Rather than a deterministic approach, the SET recognizes that similar events can result in various stream morphologies, while dissimilar events can result in a single, dominant stream morphology. The probability of a particular future state is strongly predicated by the relative influence of geology, hydrology, and biology. The SET assumes dynamic morphological evolution through time and recognizes variable rates of change for both spatial and temporal scales, along with numerous potential trajectories.
Having introduced the SET, evidence from completed projects will be presented as case studies for application in innovative stream restoration. Potential utility of the SET in stream restoration planning and design stems from improved understanding and explanation of morphological “stream states”, explicitly including the role of biology, which provides insights into appropriate restoration strategies to counter adverse impacts from past disturbance, while building future resilience.
PRESENTATION TITLE, Applied Research Efforts to Improve the Design, Implementation and Management of Ecological Restoration in North Carolina.
Dr. Barbara Doll, North Carolina State University.
Stream restoration is “big business” with over a billion dollars spent annually on restoration projects across the US. North Carolina is recognized as a national leader in stream restoration innovation, design and implementation. The rise of restoration in N.C. was in part due to the leadership, creativity and innovation afforded by the formation of the NC State University Stream Restoration Program (SRP) in the late 90’s. A partnership of the Biological & Agricultural Engineering Department and NC Sea Grant, the SRP is a team of faculty, staff, and students working to improve water quality and aquatic ecology through research, demonstration projects, and education. Following two decades of developing, testing, demonstrating and evaluating natural channel design focused restoration practices, the SRP now focuses heavily on evaluating the ecological performance and functional uplift and the metrics and tools for gauging these outcomes. The SRP also offers a series of River Course workshops with 4-6 short courses a year attended by more than 200 restoration professionals and a biennial stream conference, EcoStream, which attracts 350-400 participants. Since inception, the SRP has provided training and education to more than 6000 professionals in stream assessment, design, construction, modeling and monitoring.
Commonly stated goals for stream restoration include enhancing water quality, improving aquatic habitat, stabilizing stream banks, establishing native riparian vegetation and enhancing floodplain function. Many funding agencies have realized the need to document and quantify functional performance of restoration efforts. The SRP has partnered with state and federal agencies, local governments and non-profit organizations to develop research projects focused on evaluating the ecological benefits, including water quality for restoration efforts and to identify new and innovative practices to maximize these ecological benefits. This presentation will feature several of these efforts.
SRP assessed 157 restored, impaired and reference streams during 2006-2012 using several rapid assessment tools. Macroinvertebrates were collected from 85 of the restored streams and watershed assessment was conducted for a selection of streams. Morphological design data and site-specific landscape factors were also compiled for 79 of the restored streams. Statistical analysis revealed that macroinvertebrate metrics correlated with stream assessment variables and as expected, watershed condition variables improved correlation in most cases. In addition, restored streams were found to have morphologic conditions similar to reference streams, but exhibit greater variability in aquatic habitat and bedform. Larger (wider) streams in steeper valleys with larger substrate and un-developed watersheds have higher numbers of pollution intolerant EPT taxa. Also, greater floodplain widths correlate with higher EPT taxa.
In partnership with the NC Division of Mitigation Services, NC’s in-lieu fee mitigation program, and the Environmental Defense Fund, SRP is currently evaluating functional uplift and physical and morphological adjustment of stream restoration projects in the Piedmont region of NC. In addition, to assist the state’s Department of Environmental Quality in developing proposed nutrient crediting protocols for stream restoration projects, the SRP has conducted data collection, analysis and technical advice to evaluate the three mechanisms of nutrient reduction currently being considered (i.e. streambank erosion, hyporheic exchange and increased floodplain connectivity) in order to develop nutrient crediting criteria that are based on sound science.
PRESENTATION TITLE, Stream Channel Succession and Sediment Dynamics: Black Vermillion River, KS
Dr. Tim Keane, Principal Investigator Kansas State University
The Black Vermillion River drains approximately 410 square miles in northeastern Kansas. The drainage basin of the Black Vermillion River lies within Ecoregion 47: Western Corn Belt Plains. Surface materials are dominated by alluvium and glacial drift/till. Conversion from native, warm-season tallgrass prairie to agricultural production caused significant impacts to the river channel and riparian landscape. Major channelization shortened the river by nearly 16 miles from pre-settlement dimensions; this shortening combined with the construction of numerous flow-through structures/dams have produced dramatic changes in discharge and sediment dynamics.
In 2007, nine monitored stream reaches were established within three main tributaries of the Black Vermillion River of northeast Kansas. Each reach was surveyed and assessed for channel stability. Subsequent surveys (2008-2010) were conducted along with monitoring of streambank erosion, bed scour, and sediment size/distribution shifts. Surveys allowed for geomorphic characterization, quantification of stability, and identification of stream successional sequence. This work allowed correlation of stream ‘state’ and in-channel sediment contributions, as well as prediction of future erosion rates based upon progression of stream succession.
This presentation recounts our predictions of channel succession on the Black Vermillion River and the coincident sediment yield associated with establishment of a stable channel form at current bed elevations. Calculations assume that a stable channel and floodplain at current bed elevation is the most acceptable design solution in this tillage agriculture dominated landscape. Use of natural channel design parameters allows for the prediction of stable channel form and sediment yields associated with channel succession. Our measured erosion rates and basin-specific bank erosion curves (Sass and Keane, 2012) allow prediction of the time frame for stream channel succession. Such understanding is critical in determining not only how but when to most effectively mitigate the myriad of instability consequences.
This work was supported by USDA CREES 406 Integrated Program (Grant#KS600399).
PRESENTATION TITLE, Trick or Treat: Does Natural Channel Design Work to Improve Stream Ecological Function?
Matt Kondratieff , Colorado Parks and Wildlife
Rivers that depart from natural channel forms can limit ecological recovery of aquatic ecosystems and ultimately degrade habitat. Departures include channelization, loss of floodplain connectivity, removal of wood, habitat fragmentation, and altered hydraulic conditions. Monitoring results from fish populations occupying impaired rivers have shown that recovery may require many decades before populations begin to stabilize and even longer before populations show positive signs of recovery. Fish populations occupying degraded river systems may continue to decline without active restoration intervention, such as application of Natural Channel Design (NCD). Uncertainty exists whether application of NCD result in improvements to ecological function that can last over time. In Colorado and Montana, long-term monitoring of NCD projects provide evidence that stream ecological functions have improved, such as increases in fish biomass, density, and species diversity. In addition, NCD project monitoring spanning up to 27 years have shown sustained improvement in fish populations over time. Restoration of full ecological function as compared to reference quality sites has been achieved in NCD project site in Montana but not Colorado
PRESENTATION TITLE, Stream Restoration: Does Restoring Structure Lead to Function?
Dr. Sara McMillan, Associate Professor, Agricultural & Biological Engineering
Purdue University
Efforts are underway globally to improve water quality and other ecosystem services in watersheds impacted by urbanization and agricultural production. Excess nutrients (i.e., nitrogen and phosphorus) create eutrophic conditions that threaten water supply for human consumption as well as ecological health. It has long been recognized that the interfaces between terrestrial and aquatic ecosystems are locations where nutrient processing and removal is maximized. However, these river-floodplain systems are the same environments that are the most severely degraded by human development, including piped water conveyance, river network modifications for flood control, agricultural production and infrastructure placement. Competing uses for land necessitate innovative solutions that maximize biophysical processes to reduce nutrient export. Stream and riparian restoration is one strategy that seeks to do so. Practices enhance channel stability and geomorphic complexity by reconstructing stream channels, planting riparian vegetation and connecting floodplains. The assumption is that the structural changes to mimic natural systems will allow the development of functional equivalencies as well. Our research shows that restoring stream-floodplain connectivity results in greater inputs of sediments and nutrients with subsequent impacts on nutrient biogeochemistry. This was particularly evident downstream of impaired reaches, which highlights the need to optimize placement of practices for maximum impact. We also show that time lags exist in recovery of ecosystem function following stream restoration, particularly related to biologically driven nutrient retention. This is critical for monitoring programs aimed at measuring success and ensuring sufficient time for restoration practices to achieve desired goals.
PRESENTATION TITLE, Stream and watershed restoration: guidance for restoring riverine processes and fish habitat
Dr. Philip Roni, Principal Scientist , Cramer Fish Sciences
Billions of dollars are spent annually in North America and Europe to restore rivers and improve fish habitat. Unfortunately, many of these well-intentioned efforts fail to meet their objectives because they ignore watershed processes or do not follow key steps needed to adequately plan, implement and evaluate restoration. Here I provide an overview of the eight key steps needed to plan restoration, assess watershed conditions, identify restoration actions, select and prioritize restoration techniques and monitor and evaluate their success. I provide examples of successful methods, analyses or models used to address each of these key steps. Before assessing conditions or identifying restoration opportunities, it is important to have a clearly defined restoration or recovery goal. Assessment of watershed processes and habitat conditions should include assessment of potential and current rates or conditions and identify the causes of habitat degradation and loss. In selecting appropriate restoration actions, it is important to be aware of whether the actions restore underlying processes or simply improve habitat as well as the longevity, likelihood of success, and whether they ameliorate the impacts of climate change. Several approaches exist for prioritizing restoration actions at a regional, watershed, and reach scale. The most transparent and repeatable approach for prioritizing restoration projects is multi-criteria decision analysis (scoring system) that can incorporate quantitative and qualitative information including scientific and socio-economic data. Monitoring of restoration projects needs to be designed well before the projects are implemented and have clear testable hypotheses and a rigorous study design. Unfortunately, many monitoring programs fail not because of inadequate design, but because of poor implementation, quality control and management – all factors that can usually be overcome by diligent project management. The steps and considerations outlined in this presentation, if followed, should ensure that restoration actions are effective at restoring watershed processes and habitat.
PRESENTATION TITLE, Restoring Ecological & Geomorphic Function on the Heartrock Ranch, Idaho
Dr. Dave Rosgen, Wildland Hydrology
A large-scale restoration following the Natural Channel Design approach was implemented in 2011 near Sun Valley, Idaho, with primary goals of establishing cold-water fisheries and enhancing river stability (i.e., transporting sediment and streamflows) and hydrological connectivity (longitudinal, lateral, vertical, and temporal). Assessments related to both ecological and geomorphic functioning at multiple spatial scales were conducted to direct the restoration by identifying limiting factors for various species and their habitats, including large mammals, eagles, heron, waterfowl, songbirds, and aquatic organisms. A downstream reference reach on Willow Creek was used to represent the physical and biological potential of the impaired river system.
Assessment results indicate that heavy, season-long livestock grazing, poor irrigation practices, and direct channel impacts were responsible for numerous impairments, including:
- Incised channels with disconnected floodplains
- Lack of sediment transport capacity due to overwide and shallow channel
- Poor pool quality
- Limited instream wood, undercut banks, and woody vegetation
- Invasion of fine sediments generated from accelerated streambank erosion
- No off-channel features for habitat complexity or diversity for terrestrial and aquatic species
- Poor invertebrate habitat, spawning habitat, and gravels
- Elevated water temperatures
- Limited holding cover and habitat for juvenile and adult fish species during low and high flows
Monitoring results show that average stream discharge increased even during low precipitation years, residual pool depth increased (< 0.18 m to > 0.9 m), spawning substrates increased in size (0.11 mm to 19 mm), and estimated egg-to-fry trout survival increased from less than 20% to more 90% based on the Fredle indices. Invertebrate indices of restoration effectiveness were “positive”, and fish diversity increased from three to seven species in the restored spring creeks, which matched species diversity in the post-restoration reference reach. For the two restored streams, redd counts increased dramatically (7 to 161 and from 17 to 143). Likewise, the electrofishing catch-per-unit-effort for wild trout increased dramatically (0.013 to 1.166 trout/m and 0.029 to 0.222 trout/m) for the two spring creeks as part of the larger community-level response. According to ranch accounts, the restoration and aquifer recharge approach increased hay production and reduced labor needs by converting flood irrigation to sub-irrigation.
PRESENTATION TITLE, Sediment Sources, Baseline Sediment-Transport Rates and the Effectiveness of Restoration Measures for Reducing Loads to Receiving Waters
Dr. Andrew Simon, Cardno
The impact of erosion, transport and delivery of sediment to receiving-water bodies is the focus of worldwide attention in efforts to protect drinking water, aquatic and marine resources, and maintain reservoir capacity for water supply, flood control and power generation. To adopt effective sediment-control measures to protect receiving waters, it is not sufficient to only know the magnitude of the sediment load, but also the major contributing sources. Potential sediment sources may include: uplands (from overland flow and mass movements) including gullies, dirt roads, fields and channels (bed and banks). There has long been an overemphasis on the role of uplands and fields on sediment erosion and delivery at the expense of channel processes (e.g. Chesapeake Bay, the Great Barrier Reef). This is largely due to institutional inertia that produces a reliance on watershed models to predict sediment loads, notwithstanding that these models cannot account for one of the most important sources today; streambanks.
A series of studies from the Chesapeake Bay Watershed show that streambank sediments may account for 47-95% (mean of 71%) of sediment yields. In contrast, based on watershed modeling, EPA suggests that only 30% is derived from streambanks. For example, in southern Queensland, Australia, watershed modeling showed that 60% of the suspended load delivered to the Great Barrier Reef from the Burnett River was emanating from uplands, while just 8% of the 2.76 million tonnes/y was generated from streambanks. A subsequent, detailed study of streambank erosion, however, showed by both empirical and modeling approaches that streambank erosion accounted for between 44% and 73% of the average, annual-suspended load.
The locus of sediment erosion has shifted from the uplands to the channel systems as soil-conservation measures improved and rivers adjusted to influxes of agricultural sediment and other anthropogenic activities. These periods of instability are marked by increases in sediment-transport rates. Contributions from channel sources, particularly streambanks can typically be in excess of 50% of the total suspended-sediment load. Transport rates from stable or re-equilibrated systems, however, are used to determine baseline or “reference” transport rates. Examples from various ecoregions are provided and range over several orders of magnitude.
It is, therefore, critical to use the appropriate analytic tools if one hopes to be able to accurately determine magnitudes of sediment delivery from various sources, and to determine effective sediment-reduction strategies. For streambanks, the dynamic version of the Bank-Stability and Toe-Erosion Model (BSTEM) is used to simulate bank erosion over extended flow periods. Used in combination with observations of the longitudinal extent of failing banks, unit loadings (per m of channel length) are extrapolated to determine bank-generated sediment loads. Predictions of important load reductions along with the effectiveness and cost-effectiveness of a range of restoration measures slope are quantified by comparing erosion rates for the same flow series under “existing” and various restoration strategies. These may include direct modification or protection of banks, riparian plantings, changes in flow regime or grade control. Examples are provided from the U.S., Australia and New Zealand.
PRESENTATION TITLE, Adaptive Management: Using Geomorphic Stream Stage and Transition and Departure Conditions to Plan and Generate Restoration
Dr. W. Barry Southerland, National W2Q Fluvial Geomorphologist
Understanding stage, transition, and channel evolution is a fundamental necessity in developing restoration practices considered to be natural channel restoration. Developing alternative restoration that operates within the natural range of physical variability based on models or analytical equations alone are at high risk of not meeting physical stability, biological objectives and diversity. Avoiding visits to the field involving critical measures of dimension pattern, profile and sediment studies to identify stable morphological stream types and the departure therein will inevitably have consequences. Adaptive management in river restoration is most completely served with this planning paradigm intact. Validation of the current stable analog, aka reference reach, in the similar hydrophysiographic region and fluvial landscape-valley type is essential.
Throughout the Pacific Northwest and the Intermountain West structural practices instead of geomorphic system and channel evolution based designs are still popular. In some areas in the West, such as the Pacific Northwest a structure name has driven design instead of natural stable dimensions, pattern, and profile associated with the type and distribution of sediment load. In many instances success and even objectives have become a moving target instead of identifying and serving the principle objectives stated on permits and funding documentation. Impacts on water quality are potentially a concern.
This paper discusses both river restoration successes and failures due to the consequences of not completing an analysis of stage, transition, channel evolution and departure analysis. In some instances extreme wood structures have been designed without the consideration of riparian vegetation plan and practice. In other instances, even when bank stability was stated as a design objective, extreme lateral recession occurred next to structures and it was acceptable because it was considered a natural process. In other instances, lack of consideration of the socio-economic landscape was not considered in the planning process. Channel evolution, stage of adjustments, and identification of a stable morphological geomorphic stream type within the given hydrophysiographic region with valley landscape types are essential to base line adaptive management and riparian ecological stage and transition. These are pre-requisites for appropriate and robust natural channel restoration.
PRESENTATION TITLE, Land Use Change impact on Channels
DR. Sandy Verry, Ellen River Partnership; Research Hydrologist Emeritus,
USDA Forest Service
River width is determined by watershed area, climate and stream type; but changes in land use can cause a doubling of channel size along with a 400% increase in sediment yield as channels evolve. The root causes are an increase in channel discharge resulting from a desynchronization of snowmelt, soil compaction during wet weather logging and changes in watershed roughness largely caused by the loss of mature trees. Channel discharge increases 2 to 3 times over the 1 to 50-year frequency range. Compared with land rebound from glacial melt, land use channel changes occur in mostly a 50-year time span rather than thousands of years and are in the range of 1-ft vertical and 1-ft horizontal per year compared with 1- or 2-mm per year for land rebound adjustments. More frequent and larger storms caused by climate change may also cause channel adjustments especially in narrow valleys with limited floodplains where bridges are a better long-term bet than culverts.
PRESENTATION TITLE, Regional Sediment Data and Regional Curves: Increasing Confidence in Designs through Competence, Capacity and Support
Alan Walker, Streamwalker Consulting, LLC and Consulting Agent/Project Manager, Resource Institute, Inc.
Excess sediment in the stream corridor contributes to many issues in the watershed including public water supplies, flooding, aquatic habitat, and impoundments/receiving waters. Raising the awareness of the amount of sediment entering the stream systems from stream bank erosion is not only a water quality issue, but a key component in the assessment and proposed solutions to address this natural resource concern.
Field practitioners of natural channel design must incorporate two major data resources into the process of assessment and design.
Field practitioners need local hydro-physiographic data to correlate regional curve data for use in validating bankfull and sediment data as well as channel competence and capacity for design alternatives evaluation. Collecting and analyzing sediment data using USGS field techniques allows the development of regional sediment curves. The sediment curves in conjunction with regional curve discharge data can be used in the development of dimensionless sediment curve data for use in assessment and design. RIVERMorph™ software is an excellent tool for incorporating this data and evaluating existing cross sections for competence and capacity as well as proposed cross sections. Utilizing regional curve data and sediment data to design appropriate width/depth ratios are vital components of successful stream restoration and/or stabilization projects.