Comparing the functional recognition of aesthetics,hydrology, and quality in urban stream restoration through the framework of environmental perception

This study explores the application of a civic perception analysis in the context of stream restoration as a social‐ecological system (SES). Analysing such a SES is useful for understanding correlations between civic interests and environmental conditions in river restoration. An analytic hierarchy process (AHP) analysis was used to quantify the demand for restoration objectives. Additionally, an image‐based survey was used to precisely capture residents' perceptions of urban stream restoration by comparing aesthetic images, hydrologic functions, and environmental quality. Based on the AHP results, a hierarchical multiple regression was derived. A total of 181 participants responded to our survey, and the results were summarized by each subwatershed in the An'Yang watershed. The results demonstrated that the perceptions of residents who live in various environmental and regional conditions may manifoldly reflect their personal visual and aesthetic preferences by subwatershed. The upstream subwatershed values (SW1 = 7.86 and SW2 = 7.39) were higher than those in the downstream areas (SW5 = 5.28 and SW6 = 5.15). Consequently, this hierarchical multilevel model showed that individual environmental perception was highly associated with visual preference regarding stream restoration at the subwatershed level (p < 0.001). Urban environmental and spatial planners could use such information when restoring and designing waterfront spaces.     

Governance in a River Restoration Project in South Korea: The Case of Incheon

This research aims to explore an emergence of river governance in Incheon, South Korea, in relation to the Incheon Stream Restoration Project from 2003 to 2010. The purpose of the project is to restore local streams in Incheon for improvement of ecological restoration, water quality, flood prevention, and waterfront amenities for local residents. The project epitomizes the ethos of river governance through accommodation of views from various stakeholders, such as the government, nongovernmental organizations, local residents, and experts through establishment of the Stream Restoration Propulsion Group (SRPG). The enactment of the Special Ordinance for the SRPG has served to help the governance system work in the project. The interim assessment of the project in terms of river governance and ecological restoration indicates that the project has achieved a good degree of river governance coupled with a limited range of ecological restoration. The key to the success of the project hinges upon a continuous collaboration between the stakeholders to achieve river restoration, particularly political bargaining between the government and the other stakeholders.     

Monitoring the channel process of a stream restoration project in an urbanizing watershed: a case study of Kelley Creek,Oregon, USA

Pacific Northwest (PNW) streams in the United States were impacted by the 20th century development, when removal of instream structure and channelization degraded an aquatic habitat. The lower Kelley Creek in southeast Portland, USA was channelized during the 1930's Works Progress Administration (WPA) projects. Stream restoration reintroduced pool‐riffle sequences and heterogeneous substrates to protect salmonids while mitigating impacts from flooding. We investigated whether the restored pool‐riffle morphology changed substantially following effective discharge events. We examined channel forms for four reaches representing three time periods—pre‐development (two reference reaches), development and restoration. We conducted thalweg profiles, cross‐sections and pebble counts along the reaches to examine how channel geometry, residual pool dimensions and particle size distribution changed following effective discharge events. The effective discharge flows altered the restoration reach more substantially than the reference reaches. The restoration reach decreased in median particle size, and its cross‐sectional geometry aggraded near its margins. However, the residual pool morphology remained in equilibrium. Richardson Creek's reference reach degraded at the substrate level, while Kelley Creek's reference reach remained in equilibrium. The restoration reach's aggradation may have resulted from sedimentation along the nearby Johnson Creek. In contrast, Richardson Creek's degradation occurred as upstream land use may have augmented flows. Stream channels with low gradient pool‐riffle morphologies are ideal for salmonid spawning and rearing and should be protected and restored within urban corridors. The findings of our study suggest that the connectivity of streams and the dynamic fluvial geomorphology of stream channels should be considered for stream restoration projects in humid temperate climates. Copyright © 2008 John Wiley & Sons, Ltd.     

Contribution to decision‐making on establishing the maximum water level for Lake Vegoritida

The water level in Lake Vegoritida, Greece, has undergone great changes over the past decades attributable to severe water abstraction directly from the lake and its catchment, which affected not only the conditions of the natural environment, but also social and economic conditions. The water level of the lake is currently rising, with discussion of an agreeable decision about the desired maximum lake water level becoming a source of conflict among the lake stakeholders. The present study provides a framework for a participatory management plan, with the perspective of engaging all levels of lake stakeholders in the process of deciding and establishing the maximum lake water level. Kolb's learning cycle is used as a methodological vehicle in the proposed process of participatory decision‐making. Its contribution to decision‐making includes (a) identification of lake stakeholders and the issues arising from a potential establishment of a maximum lake water level; and (b) three suggested water level scenarios to facilitate a future constructive discussion directed to establishing a maximum water level in Lake Vegoritida.     

Assessing macroinvertebrate community response to restoration of Big Spring Run: Expanded analysis of before‐after‐control‐impact sampling designs

Stream restoration projects utilize a variety of approaches to improve conditions for aquatic organisms or enhance ecosystem function. Alterations to abiotic conditions to enhance certain ecosystems services may not lead to concurrent changes in the benthic macroinvertebrate community indicative of improved stream health. Big Spring Run was the location of a novel restoration project to recreate an anabranching “wet meadow” habitat typical of precolonization conditions without the primary goal of restoring a macroinvertebrate community characteristic of single‐channel lotic systems. We examined the effect of the restoration on the macroinvertebrate community using a multivariate analysis of assemblage composition, a before‐after‐control‐impact (BACI) approach, and an assessment of potential aerial migrants. We also examined subsets of the data using a BACI approach that represented restricted sampling designs often employed in stream restoration projects. Benthic macroinvertebrates were collected in the Spring twice prior to restoration (2010 and 2011) and 3 years after restoration (2012–2014). Adult stream insects were collected in 2014. Analyses of benthic macroinvertebrates and adult insects using the full dataset suggested that restoration had no effect on the macroinvertebrate community due to poor in‐stream conditions likely from sediment deposition following restoration. Dispersal barriers are likely acting as a secondary constraint on recolonization. Analyses using subsets of the data demonstrated that reference site quality and sampling extent can alter conclusions from a BACI approach. We found that a holistic approach using multiple lines of evidence required a nuanced approach to interpreting the data but was also informative for assessing project success. Robust monitoring protocols are likely the best approach for producing convincing results through a single line of evidence. The additional BACI analyses performed for this study, however, allowed the modest sampling regime employed to generate a broad narrative demonstrating that the macroinvertebrate assemblage did not respond to this type of restoration. Thus, we believe the holistic approach we employed can strengthen assessments of stream restoration projects when resources for monitoring are limited.     

DISTRIBUTION AND ABUNDANCE OF STREAM FISHES IN RELATION TO BARRIERS: IMPLICATIONS FOR MONITORING STREAM RECOVERY AFTER BARRIER REMOVAL

Dams are ubiquitous in coastal regions and have altered stream habitats and the distribution and abundance of stream fishes in those habitats by disrupting hydrology, temperature regime and habitat connectivity. Dam removal is a common restoration tool, but often the response of the fish assemblage is not monitored rigorously. Sedgeunkedunk Stream, a small tributary to the Penobscot River (Maine, USA), has been the focus of a restoration effort that includes the removal of two low‐head dams. In this study, we quantified fish assemblage metrics along a longitudinal gradient in Sedgeunkedunk Stream and also in a nearby reference stream. By establishing pre‐removal baseline conditions and associated variability and the conditions and variability immediately following removal, we can characterize future changes in the system associated with dam removal. Over 2 years prior to dam removal, species richness and abundance in Sedgeunkedunk Stream were highest downstream of the lowest dam, lowest immediately upstream of that dam and intermediate farther upstream; patterns were similar in the reference stream. Although seasonal and annual variation in metrics within each site was substantial, the overall upstream‐to‐downstream pattern along the stream gradient was remarkably consistent prior to dam removal. Immediately after dam removal, we saw significant decreases in richness and abundance downstream of the former dam site and a corresponding increase in fish abundance upstream of the former dam site. No such changes occurred in reference sites. Our results show that by quantifying baseline conditions in a small stream before restoration, the effects of stream restoration efforts on fish assemblages can be monitored successfully. These data set the stage for the long‐term assessment of Sedgeunkedunk Stream and provide a simple methodology for assessment in other restoration projects. Copyright © 2011 John Wiley & Sons, Ltd.     

LONG‐TERM MONITORING AND ASSESSMENT OF A STREAM RESTORATION PROJECT IN CENTRAL NEW YORK

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.     

A Synthesis of Stream Restoration Efforts in Florida (USA)

Studies summarizing stream restoration projects in the US are outdated and omit the majority of restoration projects in Florida. To address this gap, we compiled stream restoration data from diverse sources to create a Florida Stream Restoration Database (FSRD, available at http://www.watershedecology.org/databases.html ) containing information on project type, location, completion date, and costs. The FSRD contains 178 projects categorized by restoration type, including riparian management (23%), stream reclamation (19%), flow modification (13%), bank stabilization (12%), channel reconfiguration (11%), in‐stream habitat improvements (11%), floodplain reconnection (6%), invasive species removal (4%), and dam removal (1%). Projects were spatially clustered into three geographic regions, providing insight on the diversity of initiatives, needs, and funding sources of land management agencies and private landowners that motivated restoration efforts. Projects in the Florida panhandle emphasized in‐stream habitat restoration, while peninsular projects were dominated by flow modification, and projects in the west central region focused on stream reclamation to mitigate surface mining practices and water quality and habitat improvements in tidal streams. Results suggest that Florida is spending much more on stream restoration than previously documented. Between 1979 and 2015, the mean and median stream restoration project costs in Florida were $15.4 million and $180 000, respectively, indicating a strongly skewed distribution because of the large Kissimmee River restoration project in central Florida. This work highlights the need for, and utility of, statewide and national restoration databases to improve restoration tracking. This need will become increasingly critical as more stringent water quality and habitat mitigation rules are implemented across the country. Copyright © 2016 John Wiley & Sons, Ltd.     

Population effect of a large‐scale stream restoration effort on Chinook salmon in the Pahsimeroi River,Idaho

Stream habitat restoration is an important tool for fisheries management in impaired lotic systems. Although small‐scale benefits of stream habitat restoration are commonly investigated, it is difficult to demonstrate population effects. The Pahsimeroi River Chinook salmon Oncorhynchus tshawytscha population was previously restricted to the lower portion of the river by multiple irrigation structures. To address fish passage issues, a combination of restoration projects was initiated including barrier removals, instream flow enhancements and installation of fish screens on diversions. The largest barrier was removed in 2009, more than doubling the amount of accessible linear habitat. We hypothesized restoration efforts would expand the distribution of spawning salmon in the Pahsimeroi River watershed, leading to a broader distribution of juveniles. We also hypothesized a broader juvenile distribution would have population effects by reducing the prevalence of density‐dependent growth and survival. Redds were documented in newly accessible habitat immediately following barrier removal and accounted for a median of 42% of all redds in the Pahsimeroi River watershed during 2009–2015. Snorkel surveys also documented juvenile rearing in newly accessible habitat. Juvenile productivity increased from a median of 64 smolts/female spawner for brood years 2002–2008 to 99 smolts/female spawner for brood years 2009–2014. Overall, results suggested increased habitat accessibility in the Pahsimeroi River broadened the distribution of spawning adult and rearing juvenile salmon and reduced the effects of density‐dependent survival. Large‐scale stream restoration efforts can have a population effect. Despite the large‐scale effort and response, habitat restoration alone is likely not sufficient to restore this population.     

Better governance for integrated management of the Lake Biwa—Yodo River Basin

The present study discusses the efforts of the Union of Kansai Governments to resolve serious issues in the Lake Biwa—Yodo River Basin in Japan. It identifies many of the issues related to the basin on a ‘no man's land’ mindset of today's governmental framework, which has constrained both the will and the approach to remedy the associated problems. It also highlights better governance that not only encourages individual efforts, but also promotes collaboration and cooperation among the major stakeholders in the area, as important to developing acceptable solutions to relevant issues. The present study also recognizes objective scientific evidence as an effective driver for improving governance, being the basis for making informed decisions and highlighting the use of appropriate indicators to evaluate the conditions characterizing a specific location or the basin as a whole. The present study also describes the Union of Kansai Governments as a behind‐the‐scenes coordinator that gathers knowledge and intelligence on the basin, and works to integrate policies by getting basin stakeholders to gradually improve governance by repeating a cycle of: (a) recognizing the current situation; (b) identifying relevant issues to be addressed; (c) establishing a framework and policy for collaboration and corporation; and (d) taking necessary actions. To this end, the present study discusses the studies and efforts of the Union of Kansai Governments to develop and implement integrated management of this important interlinked lake–river water system in Japan.     

Monitoring and assessment of a river restoration project in central New York

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.     

Habitat Restoration in the Context of Watershed Prioritization: The Ecological Performance of Urban Stream Restoration Projects in Portland,Oregon

In Portland (Oregon, USA), restoration actions have been undertaken at the watershed scale (e.g. revegetation and stormwater management) to improve water quality and, where water quality and quantity are adequate at the reach scale, to increase habitat heterogeneity. Habitat enhancement in urban streams can be important for threatened species, but challenging, because of altered catchment hydrology and urban encroachment on floodplains and channel banks. To evaluate reach‐scale restoration projects in the Tryon Creek watershed, we sampled benthic macroinvertebrates and conducted habitat quality surveys pre‐project and over 4 years post‐project. Species sensitive to pollution and diversity of trophic groups increased after restoration. Taxonomic diversity increased after restoration but was still low compared with reference streams. We found no significant changes in trait proportions and functional diversity. Functional diversity, proportion of shredders and semivoltine invertebrates were significantly higher in reference streams than in the restored stream reaches. We hypothesized that inputs of coarse particulate organic matter and land use at watershed scale may explain the differences in biodiversity between restored and reference stream reaches. Habitat variables did not change from pre‐project to post‐project, so they could not explain community changes. This may have been partly attributable to insensitivity of the visual estimate methods used but likely also reflects the importance of watershed variables on aquatic biota—suggesting watershed actions may be more effective for the ecological recovery of streams. For future projects, we recommend multihabitat benthic sampling supported by studies of channel geomorphology to better understand stream response to restoration actions. Copyright © 2014 John Wiley & Sons, Ltd.     

Participation: Rhetoric and Reality. The Importance of Understanding Stakeholders Based on a Case Study in Upper East Ghana

Based on the views of a number of stakeholders involved in the development of small reservoir systems in the Upper East Region of Ghana in West Africa, this paper examines the importance of understanding the stakeholders whom the international development community wants to include in its participatory approaches. The paper also aims to show that terms such as ‘participation’, ‘participatory approach’ and ‘participatory planning’ are often used in project proposals, but that in reality the extent to which stakeholders are actually able to participate in projects is limited. This limitation is often due to a lack of understanding by the project organization of the interests and views of the stakeholders, which are then not incorporated in the project process. A stakeholder analysis could provide more insight in the interests, goals and views of all stakeholders involved in a project, as well as in the differences between the stakeholders. In the development of water resources, the long-term sustainability of a project's work is dependent on the manner in which relevant (often local) stakeholders continue the process after the official time of the project has ended. Thus, since the project is dependent on the involvement of relevant stakeholders, the formulation of adequate and appropriate forms of stakeholder engagement that will ensure information exchange and participation is essential. However, as the case study shows, such analyses were not always carried out, thus leading to a number of problems with project implementation and also with transplantation from one region, district or community to another.     

Reflexive learning in adaptive management: A case study of environmental water management in the Murray Darling Basin,Australia

Adaptive management is a structured approach for people who must act despite uncertainty and complexity about what they are managing and the impacts of their actions. It is learning‐by‐doing through deliberate cycles of experimentation, review, and synthesis. However, understanding the processes of learning and how they relate to achieving resource management goals is in its infancy. Reflexive learning—a process of identifying and critically examining assumptions, values, and actions that frame knowledge—is critical to the effectiveness of adaptive management. It involves adaptive feedbacks between stakeholders as they examine assumptions, values, and actions. Adaptive management has been applied to environmental flows because it offers a system for making decisions about tradeoffs. In the Murray Darling Basin (MDB), Australia, adaptive management is applied as a cycle of plan, do, monitor, and learn, facilitated by short‐ and long‐term learning among stakeholders. An alternative conceptualization of adaptive management as an integration of single‐, double‐, and triple‐loop learning across multiple levels of governance is presented. This is applied to environmental flows in the MDB to map adaptive feedbacks of reflexive learning. At the lowest level of governance (Water Resource Planning Area), goals are assessed as Thresholds of Potential Concern related to flow‐ecology responses, which are reviewed every 3–6 years. At the second level of governance (Basin‐States), Water Management Targets are the key goals; reviewed and reframed every 6–10 years. The highest level of governance (the MDB) is concerned with policy targets, with review and reframing over 8–15 years. Feedbacks that generate reflexive learning are complex and require commitment to move through the modes of single‐, double‐, and triple‐loop learning. Effective adaptive management of environmental water requires practitioners to situate themselves within a matrix of information flow across modes of learning, levels of governance, and components of a social‐ecological system, where reflexive learning drives the achievement of management goals.     

Effects of large woody debris on surface structure and aquatic habitat in forested streams,southern interior British Columbia,Canada

It is well known that large woody debris (LWD) plays an important functional role in aquatic organisms' life. However, the influence of LWD on channel morphology and aquatic environments at watershed levels is still unclear. The relationships between wood and surface structure and aquatic habitat in 35 first through fifth order streams of southern interior British Columbia were investigated. Study streams in the channel networks of the study watersheds were classified into four size categories based on stream order and bankfull width: Stream size I: bankfull width was less than 3 m, Stream size II: 3–5 m, Stream size III: 5–7 m, Stream size IV: larger than 7 m. We found the number of functional pieces increased with stream size and wood surface area in stream sizes I, II and III (24, 28 and 25 m²/100 m², respectively) was significantly higher than that in stream size IV (12 m²/100 m²). The contribution of wood pieces to pool formation was 75% and 85% in stream sizes II and III, respectively, which was significantly higher than those in stream size I (50%) and size IV (25%). Between 21% and 25% of wood pieces were associated with storing sediment, and between 20% and 29% of pieces were involved in channel bank stability in all study streams. Due to long‐term interactions, LWD in the intermediate sized streams (Size II and III) exhibited much effect on channel surface structure and aquatic habitats in the studied watersheds. Copyright © 2008 John Wiley & Sons, Ltd.     

Stream Temperature Impacts Because of Changes in Air Temperature,Land Cover and Stream Discharge: Navarro River Watershed,California, USA

Stream temperatures are critically important to aquatic ecology, especially cold‐water fish such as salmonids. Stream temperatures are influenced by multiple factors, including local climate, solar radiation on the stream channel, stream discharge volume and groundwater contributions. The Heat Source hydrodynamic and thermodynamic numerical model was used to evaluate temperatures in three stream reaches in the Navarro River watershed, California, USA. The model was calibrated and validated for summer 2015 conditions and then applied to scenarios that address changes in air temperatures, riparian forest cover and stream discharge. Modelling results indicate that stream temperatures are sensitive to changes in air temperatures and riparian forest cover and that higher discharge volume mitigates those impacts. Modelled stream maximum weekly average temperatures (MWAT) increased by 1.5–2.3°C in response to an air temperature increases of 3.5°C under low flow conditions (drought) but by only 0.9–2.0°C under moderate flow. Complete removal of riparian forest in a large‐scale forest fire would increase MWAT by 2.2–5.9°C in low discharges and by 1.0–4.4°C under moderate discharge. Riparian zone reforestation would decrease MWATs by less than 0.8°C, a modest change reflecting high existing shade on the modelled stream reaches. Comparison of identical climate and land cover change scenarios under low and moderate discharge conditions reveals that efforts to conserve stream discharge volume could be an effective mechanism to mitigate stream temperature increases. Copyright © 2016 John Wiley & Sons, Ltd.     

Quantifying the hydrological effects of stream restoration in a montane meadow,northern California,USA

Stream restoration efforts, particularly within meadow systems, increasingly rely on ‘pond and plug’ type methods in which (a) alluvial materials are excavated from the floodplain, forming ponds; (b) excavated alluvial materials are used to plug incised channels and (c) smaller dimension channels are restored to the floodplain surface. A commonly stated objective of these efforts is to restore ecologically significant hydrological processes to degraded riparian systems. However, little research has been conducted to evaluate and quantify the restoration of these hydrological processes. Direct comparisons of pre‐ and post‐restoration hydrological observations are often misleading due to an inter‐annual climatic variability. To overcome this issue and accurately quantify the hydrological effects of restoration, we developed, calibrated and validated a hydrological model of a 230 ha mountain meadow along a 3.6 km restored reach of Bear Creek in the northeastern California. We then applied the model to simulate the pre‐ and post‐restoration scenarios by altering the floodplain topography and stream channel networks. Our results document three general hydrological responses to the meadow restoration effort: (1) increased groundwater levels and volume of subsurface storage; (2) increased frequency/duration of floodplain inundation and decreased magnitude of flood peaks and (3) decreased annual runoff and duration of baseflow. This study supports and quantifies the hypothesis that ‘pond and plug’ type stream restoration projects have the capacity to re‐establish hydrological processes necessary to sustain riparian systems. In addition, the results of this study can be used to improve quantitative objectives for ‘pond and plug’ type stream restoration activities in similar settings. Copyright © 2008 John Wiley & Sons, Ltd.     

MODELLING CHANGES IN SALMON HABITAT ASSOCIATED WITH RIVER CHANNEL RESTORATION AND FLOW‐INDUCED CHANNEL ALTERATIONS

The River2D two‐dimensional hydraulic and habitat model was used to simulate fall‐run Chinook salmon (Oncorhynchus tschawytscha) spawning and fry and juvenile rearing habitat of the first phase of a stream channel restoration project on Clear Creek, California. Habitat was simulated for a range of stream flows: (1) before restoration; (2) based on the restoration design; (3) immediately after restoration; and (4) after one and two large flow events. Hydraulic and structural data were collected for three sites before restoration, and prerestoration habitat was simulated. Habitat simulated for these sites was extrapolated to the prerestoration area based on habitat mapping. The topographical plan for the restoration was used to simulate the anticipated habitat after restoration. Although the restoration increased spawning habitat, it was less successful for rearing habitat. Channel changes associated with high‐flow events did not entirely negate the benefits of the restoration project. The results of this study point out the need for models that can simulate the changes in channel topography associated with high‐flow events, which could then be used to simulate habitat over time. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.     

Instream restoration: its effects on lateral stream–subsurface water exchange in urban and agricultural streams in Southern Ontario

Instream restoration strategies do not generally consider the subsurface environment. The study of recently restored stream reaches can provide an opportunity to assess the impacts of restoration on surface–subsurface exchange. In this study, lateral hyporheic zones occurring in a constructed gravel bar and re‐meandered stream reach were examined, using hydrometric data in combination with differences in background conservative ion and tracer injection experiments. Both the constructed gravel bar and the meander bends induced lateral hyporheic exchange flow. In the gravel bar, lateral hyporheic exchange increased after a riffle‐pool sequence was constructed in the channel adjacent to the bar. The substrate in the meander bends had low saturated hydraulic conductivity, and the stream–subsurface exchange was limited despite the large change in channel configuration. These results suggest that to enhance and maintain stream–subsurface water exchanges, restoration projects that modify horizontal geometry should involve construction of vertical morphologic features, and where floodplain sediments are fine‐grained, the addition of coarse sediments should also be incorporated in the design. Copyright © 2007 John Wiley & Sons, Ltd.     

The stream evolution triangle: Integrating geology,hydrology, and biology

The foundations of river restoration science rest comfortably in the fields of geology, hydrology, and engineering, and yet, the impetus for many, if not most, stream restoration projects is biological recovery. Although Lane's stream balance equation from the mid‐1950s captured the dynamic equilibrium between the amount of stream flow, the slope of the channel, and the amount and calibre of sediment, it completely ignored biology. Similarly, most of the stream classification systems used in river restoration design today do not explicitly include biology as a primary driver of stream form and process. To address this omission, we cast biology as an equal partner with geology and hydrology, forming a triumvirate that governs stream morphology and evolution. To represent this, we have created the stream evolution triangle, a conceptual model that explicitly accounts for the influences of geology, hydrology, and biology. Recognition of biology as a driver leads to improved understanding of reach‐scale morphology and the dynamic response mechanisms responsible for stream evolution and adjustment following natural or anthropogenic disturbance, including stream restoration. Our aim in creating the stream evolution triangle is not to exclude or supersede existing stream classifications and evolutionary models but to provide a broader “thinking space” within which they can be framed and reconsidered, thus facilitating thought outside of the alluvial box.