A widespread lack of post‐project appraisals (PPAs) not only hinders progress in the field of river restoration but also limits the application of adaptive management – a powerful heuristic tool particularly well suited to dynamic fluvial environments. In an effort to contribute to the limited body of scientific literature pertaining to PPAs, we evaluated a stream restoration project completed in the fall of 2005 in central New York. Using a variety of evaluation approaches, we documented both successes (e.g. enhanced in‐stream habitat) and short‐comings (e.g. channel avulsions). Overall, we concluded that the project was marginally successful in achieving its stated goals and that future prospects remain uncertain based on current trajectory. Lessons learned from this monitoring study include: (i) protect vulnerable banks and floodplains until vegetation is established, e.g. via integrated bio‐ and geo‐technical methods, (ii) perform scour depth analyses and excavate scour pools associated with hydraulic structures to design depth to prevent clogging of the channel during post‐construction floods, (iii) orient bank vanes such that cross‐stream flows are not deflected towards the bank, (iv) cross‐validate restoration designs via multiple methods, including process‐based sediment transport relations, especially in unstable gravel‐bed rivers, (v) anticipate and fund for fixing natural channel design (NCD) projects for 3–5 years after completion to account for uncertainties and (vi) identify measurable, goal‐specific success criteria that account for watershed scale stressors and site constraints prior to construction to facilitate successful project design and ensure effective outcomes appraisal. Copyright © 2010 John Wiley & Sons, Ltd.

The proportional contributions of stream bank and surface sources to fine sediment loads in watersheds in New York State were quantified with uncertainty analysis. Eroding streamside glacial drift, including glaciolacustrine deposits, were examined to help explain variations in the proportional contributions made by bank erosion. Sediment sources were quantified by comparing concentrations of the bomb-derived radionuclide 137 Cs in fluvial sediment with sediment from potential source areas such as agricultural soils, forest soils and stream banks.To compare sediment sources in streams where deposits of fine-grained glacial drift were abundant with watersheds that lacked moderate or extensive streamside deposits, samples were taken from fifteen watersheds in the region. The mean contribution of bank erosion to sediment loads in the six streams with glaciolacustrine deposits was 60% (range 46 to 76%). The proportional contribution of bank erosion was also important in one stream lacking glaciolacustrine deposits (57%) but was less important in the remainder with contributions ranging from 0 to 46 %. Data from this study on the varying contributions of bank erosion and data from past studies of sediment yield in fifteen watersheds of New York State suggest that eroding streamside glacial deposits dominate sediment yield in many watersheds. In other watersheds, past impacts to streams such as channelization have also resulted in high levels of bank erosion.

Sediment tracers were used to quantify erosion from cultivated fields and identify major source areas of channel bottom sediment within the Wildhorse Creek drainage, an intensively cropped tributary of the Umatilla River in northeastern Oregon, USA. Available data indicated that Wildhorse Creek was one of the largest sediment yielding tributaries of the Umatilla River. Carbon, nitrogen and the nuclear bomb-derived radionuclide 137 Cs were used as tracers to fingerprint sediment sources. Sediment was collected from the stream bottom and active floodplain and compared to samples from cultivated fields and channel banks. Samples were characterized on the basis of tracer concentrations and a simple mixing model was used to estimate the relative portion of bottom sediment derived from cultivated surface and channel banks. The results indicate that the amount of bottom sediment derived from cultivated surface sources was less than 26 per cent for the 1998 winter season, although this estimate has a high margin of error. Cesium-137 was also used to estimate surface erosion from three cultivated fields in the watershed. Annual estimates of erosion since 1963 from the three sampled fields were from 3 to 7Á5 t ha À1 yr À1

We need a coherent, deliberate process to learn from failures and successes in stream rehabilitation projects. Insightful evaluations comparing projects in varied regions have been limited by the diversity of approaches and some scientific uncertainty as to how to best accomplish longer-term monitoring (Bernhardt et al., 2005; Giller, 2005; Palmer et al., 2005; Palmer and Bernhardt, 2005; Reid, 2001, Reid and Fur niss, 2002). Addressing just the critical issue of biological assessments would take an entire paper but with hundreds of natural channel design (NCD) projects completed across the country, simply evaluating their performance and impacts on bank erosion would be a step forward. Too often critiques of NCD projects have returned continually to the same few locations, and have yet to grapple with many other projects with different designs, disturbance histories, and environments. I hope this brief review will encourage better dialogue between scientists and stream rehabilitation practitioners.NCD most often seeks to restore the dimension, pattern, and profile of a disturbed river system to emulate the natural stable river (Rosgen, 2006). A stable channel is defined as a dynamic, alluvial channel whose characteristic dimensions or features do not change over engineering time scales (Niezgoda and Johnson, 2005). Stream bank erosion is a natural process, but when accelerated by human impacts creates a disequilibrium condition, although in some cases a braided river and/or anastomozing river type is the stable form (Rosgen, 2006; Jaquette et al., 2005). With a surge in funding for stream restoration in the United States, prompted by the decline of Pacific coast salmon runs and water quality problems across the country, public and private groups have spent more than $14 billion on 37 000 stream restoration projects since 1990 (Bernhardt et al., 2005). The Chesapeake Bay watershed alone had 747 projects to reconfigure channels and reduce bank erosion (Hassett et al., 2005), most completed since 1995. In North Carolina there have been over 400 NCD projects (Miller et al., 2006). Some of the most successful stream restoration in the western United States has been the simplest and least expensive, including riparian planting and controlling livestock use of riparian areas, thus allowing bank vegetation to recover which alone can sometimes much improve channel conditions (Nagle and Clifton, 2003). Other projects using NCD are quite controversial (Malakoff, 2004), with costs from $165/m in small rangeland streams to $2300/m in urban areas. Although NCD is expensive, the more common approaches of armoring banks with rock rip-rap can cost $325/m or more in medium-sized streams while berming and channelization can cost $7400/m (Lovegreen and Petlock, 2006), with both resulting in major problems with largely negative impacts on aquatic habitat. Dave Rosgen, a former regional hydrologist for the US Forest Service Rocky Mountain Region, devised the NCD approach and is its most influential proponent. Drawing on research by ...

/ The sedimentation of reservoirs is a serious problem throughout the tropics, yet most attempts to control sedimentation in large river basins have not been very successful. Reliable information on erosion rates and sources of sediments has been lacking. In regions where geologically unstable terrain combines with high rainfall, natural erosion rates might be so high that the effects of human activity are limited. Estimates of natural erosion in these situations often have been poor because of the episodic nature of most erosion during large storms and because mass-wasting may supply much of the sediment. The predominance of mass-wasting in some watersheds can result in an unexpectedly high ratio of bedload to suspended load, shifting sedimentation to "live" rather than "dead" storage within reservoirs. Furthermore, the inappropriate use of the Universal Soil Loss Equation to assess the effectiveness of erosion control measures has led to inaccurate estimates of the sediment reduction benefits that could accrue to watershed treatment efforts. Although reducing erosion from cultivated areas is desirable for other reasons, efforts aimed at reducing reservoir sedimentation by controlling agricultural sources of erosion may have limited benefits if the principal sources are of natural origin or are associated with construction of the dams and reservoirs and with rural roads and trails. Finally, the most appropriate locations for watershed rehabilitation depend on the magnitude of temporary storage of colluvium and alluvium within the river basin: Where storage volume is large and residence time of sediment very long, reducing agricultural erosion may have limited impacts on sedimentation within the expected life of a reservoir. Systematic development and analysis of sediment budgets for representative watersheds is needed to address these limitations and thereby improve both the planning of river basin development schemes and the allocation of resources towards reducing sedimentation. When sedimentation of reservoirs is the key issue, sediment budgets must focus especially on channel transport rates and sediment delivery from hillsides. Sediment budgets are especially critical for tropical areas where project funds and technical help are limited. Once sediment budgets are available, watershed managers will be able to direct erosion control programs towards locations where they will be most effective. KEY WORDS: Tropical watersheds; Sedimentation; Reservoirs; Erosion control

Monitoring, assessment and reporting of stream restoration projects have historically lagged far behind implementation. However, in recent years, rigorous post‐project assessments (PPAs) of modern stream restoration practices have steadily increased. This has helped to stimulate debate and inquiry regarding the effectiveness of restoration techniques and has provided critical feedback to practitioners and planners useful in restoration design and implementation. Nonetheless, few studies exist that track the performance of modern restoration projects over a protracted period. Instead, most are based on a brief snapshot taken during the initial post‐construction period, which may not always accurately characterize longer‐term project performance. Here, we re‐visit a stream restoration project implemented in 2005 on a third‐order stream in central New York. By repeating several of our quantitative and qualitative evaluation procedures from the original 2007 PPA we demonstrate that (i) despite several recent large flood events and the fact that the current channel geometry differs from the design/as‐built configuration, the project has made substantial progress towards the goals of channel stabilization and habitat enhancement; (ii) this more favourable, mid‐term outcome was not necessarily evident during or well‐predicted by our 2007 PPA; (iii) although continued deformation of in‐stream structures may be a harbinger of future channel instability, riparian vegetation is playing an increasingly important role in maintaining channel stability; and (iv) accurately predicting local scour depths proximal to in‐stream structures, performing a detailed sediment budget analysis, and prescribing adequate bank protection are critical to project success, especially during early stages of a project. Copyright © 2013 John Wiley & Sons, Ltd.

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