River Restoration Projects Research Articles

Environmentalism with Chinese Characteristics? Urban River Revitalization in Foshan

Human settlements have long been located on rivers, and the relationship of the place to the river functions as a deep reflection of its historical, cultural, and socio-economic traditions. This paper explores urban river revitalization in contemporary China, focusing particularly on ongoing efforts to clean up Foshan's polluted Fenjiang River. The research shows that the traditional cultural status of the waterway, which is known as the “Mother River” of Foshan, plays a paradoxically pivotal role in the project to modernize it. Interacting in complex ways with domestic and international political concerns, and popular media and internet technologies, the cultural status of the river has helped to determine both the type of environmental movement that has emerged in its defence, and the community of interests that serves as a proxy for civil society in that movement. Ultimately, this paper argues that the unique configuration of institutions and actors engaged in the Fenjiang River restoration project are emblematic of a new type of “environmentalism with Chinese characteristics.”

The four major rivers restoration project in South Korea

A massive and fast-moving £12 billion programme is underway throughout South Korea to restore its four major rivers, which following decades of poor management have become silted, polluted and flood-prone. In addition to delivering permanent measures for controlling water volumes and quality, the 3-year ‘Korean Green New Deal’ project looks set to bring significant environmental and economic benefits to much of the country. This paper describes the vast scale of the works, which include restoring 700 km of waterways, dredging over 500 million m3 of silt, building 16 dams, constructing over 1000 water-treatment facilities and installing nearly 280 GW of hydropower.

Spawning site selection and redd gravel characteristics of sea trout Salmo trutta in the lowland streams of Lithuania

Abstract To date, no characterization of spawning habitats on scientific basis was made for the eastern Baltic salmonid populations. The aim of the present study was to characterize spawning habitat preferences and redd gravel structure of sea trout in lowland streams of western Lithuania. The redd position at the habitat-unit scale, microhabitat hydrological characteristics and the redd gravel structure have been analyzed. The spawning site selection by sea trout was related to the in-stream characteristics, but not to the riparian features. Redds were positioned mainly in the transitional pool-riffle zones, associated with close proximity to potential cover for spawners. At the microhabitat scale, sites with relatively consistent hydrological parameters (mode of water depth 0.25–0.40 m, flow velocity 0.4–0.7 m s−1 and Froude number 0.2–0.4) were selected from a wide range of available sites. Egg incubation conditions, in terms of the redd gravel structure in the spring, were of intermediate quality, while varied widely within particular reaches. According to the results of the present study, it is apparent that sea trout have particular preferences for spawning sites, which should be considered in emerging river-restoration projects.

The Penobscot River, Maine, USA: a Basin-Scale Approach to Balancing Power Generation and Ecosystem Restoration

Although hydropower is a source of low-carbon energy, without careful consideration and management, dams have the potential to degrade river ecosystems and the goods and services they provide to society. Today, a broad range of hydropower interests and stakeholders are seeking approaches to hydropower development and operation that are more environmentally and socially sustainable. The Penobscot River Restoration Project ('the Project') illustrates that basin-scale approaches can provide a broader set of solutions for balancing energy and riverine environmental resources than can be achieved at the scale of individual projects. The Penobscot basin is the largest in Maine and historically supported culturally and economically significant populations of migratory fish. These migratory fish populations declined dramatically following the construction of a series of hydropower dams on the main stem river and major tributaries in the early 20th century. The Project, negotiated between a power company (PPL Corporation) and a coalition including the Penobscot Indian Nation, resource agencies, and nongovernmental conservation organizations, features the removal of two main stem dams on the lower Penobscot and improved fish passage at the dams that remain. Because of various capacity and/or operational changes, power production will be increased at the remaining dams and total hydropower energy production from the basin will be maintained or increase slightly. The Project is expected to expand considerably the proportion of the basin accessible to migratory fish and contribute to significant increases in fish populations. The Project illustrates that a basin-scale approach can potentially yield more comprehensive solutions for sustainable hydropower than can be achieved at the project scale, and we recommend that such large-scale planning processes can improve the sustainability of both regulatory licensing of existing dams as well as the planning of future dams in regions undergoing the expansion of water-management infrastructure.

Seed Rain and Revegetation of Exposed Substrates Following Dam Removal on the Elwha River

Abstract Scheduled to begin in 2011, the removal of two dams on the Elwha River, Washington, will be one of the largest dam removal and river restoration projects undertaken in the United States. One challenge associated with this project is to understand how exposure and downstream deposition of sediments presently detained behind the dams will influence patterns of revegetation and invasive species colonization following dam removal. We conducted two greenhouse experiments assessing the potential effects of reservoir sediments on germination success and growth of (1) propagules dispersed naturally via seed rain, and (2) seeds of selected native and invasive species. Observed summer seed rain density was relatively low (<125 seeds m-2). This suggests slow recolonization in the initial years following dam removal, although these results may have been influenced by sampling methods and timing. In the selected species experiment, four out of five tested species exhibited reduced germination and growth on fi...

Temporal Development of Scour Holes around Submerged Stream Deflectors

Although the deflector structures used in many fish habitat rehabilitation schemes are frequently overtopped, few studies have examined the scour patterns created around submerged models. Furthermore, laboratory studies typically test smooth-surfaced structures, when those installed in natural rivers are generally made of logs or boulders. This study uses rough-surfaced, paired deflectors to investigate the temporal evolution of scour for three overtopping ratios in identical approach flow conditions in a flume. Results show that when maintaining identical discharge, raising deflector height and thus reducing the overtopping ratio (flow depth / structure height), an increased depth and volume of scour is generated next to the structures. The location of maximum depth and the rate of scouring with time is similar for the two highest deflectors (overtopping ratios of 1.22 and 1.83), but different for the lowest deflector model (overtopping ratio of 3.67). In order to improve the success rate of river restoration projects using in-stream structures, the overtopping ratio should be used in equations that predict scour depth evolution with time.

Framework of the approximate cost estimating model for river dredging construction

Recently, construction on the Four River Restoration Project began in South Korea. The project includes the maintenance of river embankments, the development of river areas, and river dredging. Accordingly, considerable attention is being paid to the necessary budget and estimation of construction costs. However, only a few studies have been carried out for the cost estimation of construction projects for river development or maintenance. In particular, approximate construction cost estimations for river dredging have not been studied. The lack of sufficient studies on estimating the approximate construction cost of river dredging has caused some doubt about the validity of the project’s estimated construction cost. This study proposes a framework of an approximate cost estimating model for river dredging construction. For this purpose, the construction operation process, type of river section, and the combination of equipment employed for river dredging were analyzed from the historical data of river dredging projects conducted in South Korea. The appropriateness of the analysis was examined through interviews with experts in the field. The framework of the approximate cost estimating model for river dredging construction proposed in this study provides a basis from which to develop a more accurate construction cost estimation of river dredging at the planning stage.

A River System to Watch: Documenting the Effects of Saltcedar (Tamarix spp.) Biocontrol in the Virgin River Valley

spp.) can form dense, mono-typic stands and is often reported to have detrimental effects on native plants and habitat quality (Everitt 1980; Shafroth et al. 2005). Natural resource managers of these riparian areas spend considerable time and resources con-trolling saltcedar using a variety of techniques, including chemical (Duncan and McDaniel 1998), mechanical, and burning methods (Shafroth et al. 2005). Approximately one billion dollars are spent each year on river restoration projects nationally (Bernhardt et al. 2005), and a majority of these projects focus on invasive species control in the Southwest (Follstad Shah et al. 2007).A technique that has drawn much attention is the use of the saltcedar leaf beetle (

Linking Geomorphological and Ecological Responses in Restored Urban Pool-Riffle Streams

Anne Chin, Frances Gelwick, David Laurencio, Laura R. Laurencio, Morgan S. Byars and Mateo Scoggins

Legislative Consideration on the Creation of Environment-Friendly Waterside Space in Accordance with the Four Major Rivers Restoration Project

Legislative Consideration on the Creation of Environment-Friendly Waterside Space in Accordance with the Four Major Rivers Restoration Project

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

ABSTRACTA 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 &amp; Sons, Ltd.

Hydrogeophysical studies in unrestored and restored river corridors of the Thur River, Switzerland

Niklas Linde, Ilaria Coscia, Joseph A. Doetsch, Stewart A. Greenhalgh, Tobias Vogt, Philipp Schneider and Alan G. Green provide examples from the Thur River in Switzerland to recommend that geophysical surveys and geophysical monitoring be included before and after larger scale river restoration projects to determine how such operations affect aquifer morphology and infiltration patterns.

Evaluating the Response of Biological Assemblages as Potential Indicators for Restoration Measures in an Intermittent Mediterranean River

Bioindicators are essential for detecting environmental degradation and for assessing the success of river restoration initiatives. River restoration projects require the identification of environmental and pressure gradients that affect the river system under study and the selection of suitable indicators to assess habitat quality before, during and after restoration. We assessed the response of benthic macroinvertebrates, fish, bird and macrophyte assemblages to environmental and pressure gradients from sites situated upstream and downstream of a cofferdam on the River Odelouca, an intermittent Mediterranean river in southwest Portugal. The Odelouca will be permanently dammed in 2010. Principal Component Analyses (PCA) of environmental and pressure variables revealed that most variance was explained by environmental factors that clearly separated sites upstream and downstream of the partially built cofferdam. The pressure gradient describing physical impacts to the banks and channel as a result of land use change was less distinct. Redundancy Analysis revealed significant levels of explained variance to species distribution patterns in relation to environmental and pressure variables for all 4 biological assemblages. Partial Redundancy analyses revealed high levels of redundancy for pH between groups and that the avifauna was best associated with pressures acting upon the system. Patterns in invertebrates and fish were associated with descriptors of habitat quality, although fish distribution patterns were affected by reduced connectivity. Procrustean and RELATE (Mantel test) analyses gave broadly similar results and supported these findings. We give suggestions on the suitability of key indicator groups such as benthic macroinvertebrates and endemic fish species to assess in stream habitat quality and appropriate restoration measures, such as the release of peak flow patterns that mimic intermittent Mediterranean systems to combat habitat fragmentation and reduced connectivity.

Hydropeaking indicators for characterization of the Upper-Rhone River in Switzerland

River channelization and the construction of high-head storage schemes have been the basis of agricultural and socio-economic development in many alpine regions. One example is the Upper-Rhone River in Switzerland. The Upper-Rhone’s morphology changed considerably between 1863 and 1960 as a result of two major channelizations and, from 1950 on, the construction of a large number of high-head storage hydropower schemes in the catchment. These modifications have brought large benefits to the local population, at the cost, however, of substantial disturbances in aquatic and terrestrial ecosystems in and along the river. A primary factor behind these disturbances is the alteration of the natural flow regime, namely hydropeaking due to the operation of the high-head storage hydropower plants. For sustainable river-restoration projects on regulated rivers, scientists and engineers now widely accept the necessity of integrated management of the river. Different aspects such as river morphology, sediment management, water quality, temperature, and the naturally variable flow regime should be considered simultaneously. Mitigation of non-natural, sub-daily flow fluctuations due to hydropeaking is a crucial step in restoring natural flow regimes, but is especially challenging due to the economic constraints such mitigation places upon hydropower plants. With the goal of addressing this challenge, this paper proposes three indicators to describe the flow regime of rivers in alpine catchments with and without high-head storage hydropower plants. The indicators quantify: (1) the seasonal distribution and transfer of water, (2) sub-daily flow fluctuations, and (3) the intensity and frequency of flow changes. Indicators are evaluated in a case study of the Upper-Rhone River for pre- and post-impact situations, and the benefit of a multipurpose project reducing hydropeaking on hydrologic conditions is quantified. Furthermore, the paper explores the possibility of using these indicators to link aquatic and terrestrial ecosystem well being to their hydrology.

Influence of shallowness, bank inclination and bank roughness on the variability of flow patterns and boundary shear stress due to secondary currents in straight open-channels

Boundary shear stress and flow variability due to its interaction with main flow and secondary currents were investigated under conditions that extend previous research on trapezoidal channels. Secondary currents that scale with the flow depth were found over the entire width in all experiments. These findings contradict the widespread perception that secondary currents die out at a distance of 2.5 times the flow depth from the bank, a perception which is largely based on experiments with smooth boundaries. The reported results indicate that a stable pattern of secondary currents over the entire channel width can only be sustained over a fixed horizontal bed if the bed's roughness is sufficient to provide the required transverse oscillations in the turbulent shear stresses. Contrary to laboratory flumes, alluvial river bed always provide sufficient roughness. The required external forcing of this hydrodynamic instability mechanism is provided by the turbulence-generated near-bank secondary currents. The pattern of near-bank secondary currents depends on the inclination and the roughness of the bank. In all configurations, secondary currents result in a reduction of the bed shear stress in the vicinity of the bank and a heterogeneous bank shear stress that reaches a maximum close to the toe of the bank. Moreover, these currents cause transverse variability of 10–15% for the streamwise velocities and 0.2 u * 2–0.3 u *  2 for the bed shear stress. These variations are insufficient to provide the flow variability required in river restoration projects, but nevertheless must be accounted for in the design of stable channels.

Does river regulation increase the dominance of invasive woody species in riparian landscapes?

ABSTRACTAim A regional analysis was used to explore the influence of river regulation on the dominance of non‐native, invasive shrubs and trees. We addressed the following questions: (1) How do large dams affect hydrological parameters that influence riparian vegetation? (2) How do flow regimes affect the dominance of non‐native woody species? (3) How do changes in flow regimes affect the dominance of non‐native woody species?Location South‐western USA.Methods We sampled the canopy cover of woody species on 179 point bars along seven non‐dammed and thirteen dammed river segments. Wilcoxon rank sum tests were used to determine differences between flow parameters in dammed and non‐dammed rivers. We used correlation analyses and generalized linear model comparisons to examine associations of flow parameters and canopy cover of native (Populus and Salix) and non‐native (Tamarix and Elaeagnus) taxa. An index of flow alteration that was created using principal components analysis was regressed with vegetation cover.Results Tamarix cover was positively related to drainage area, flow constancy, August and May median flow and flow recession rate, but Elaeagnus cover was unrelated to flow variables. River segments with peak flows in late summer or high constancy had the highest Tamarix cover. Populus cover was positively influenced by low maximum temperatures and frequent high pulses. Flow alteration was negatively related to Populus cover and positively related to Tamarix cover. Total non‐native, Elaeagnus and Salix covers were not correlated with flow alteration.Main conclusions Rivers with a large drainage area and low flow variability are inherently more vulnerable to invasions. River regulation does not necessarily increase the cover of non‐native, invasive species. Instead, changes in flow allow proliferation of species that have life‐history traits suited to modified flow regimes. River restoration projects that aim to reinstate natural flow regimes should be designed with knowledge of native and non‐native species' life history strategies.

River restoration, habitat heterogeneity and biodiversity: a failure of theory or practice?

Summary1. Stream ecosystems are increasingly impacted by multiple stressors that lead to a loss of sensitive species and an overall reduction in diversity. A dominant paradigm in ecological restoration is that increasing habitat heterogeneity (HH) promotes restoration of biodiversity. This paradigm is reflected in stream restoration projects through the common practice of re‐configuring channels to add meanders and adding physical structures such as boulders and artificial riffles to restore biodiversity by enhancing structural heterogeneity.2. To evaluate the validity of this paradigm, we completed an extensive evaluation of published studies that have quantitatively examined the reach‐scale response of invertebrate species richness to restoration actions that increased channel complexity/HH. We also evaluated studies that used manipulative or correlative approaches to test for a relationship between physical heterogeneity and invertebrate diversity in streams that were not in need of restoration.3. We found habitat and macroinvertebrate data for 78 independent stream or river restoration projects described by 18 different author groups in which invertebrate taxa richness data in response to the restoration treatment were available. Most projects were successful in enhancing physical HH; however, only two showed statistically significant increases in biodiversity rendering them more similar to reference reaches or sites.4. Studies manipulating structural complexity in otherwise healthy streams were generally small in scale and less than half showed a significant positive relationship with invertebrate diversity. Only one‐third of the studies that attempted to correlate biodiversity to existing levels of in‐stream heterogeneity found a positive relationship.5. Across all the studies we evaluated, there is no evidence that HH was the primary factor controlling stream invertebrate diversity, particularly in a restoration context. The findings indicate that physical heterogeneity should not be the driving force in selecting restoration approaches for most degraded waterways. Evidence suggests that much more must be done to restore streams impacted by multiple stressors than simply re‐configuring channels and enhancing structural complexity with meanders, boulders, wood, or other structures.6. Thematic implications: as integrators of all activities on the land, streams are sensitive to a host of stressors including impacts from urbanisation, agriculture, deforestation, invasive species, flow regulation, water extractions and mining. The impacts of these individually or in combination typically lead to a decrease in biodiversity because of reduced water quality, biologically unsuitable flow regimes, dispersal barriers, altered inputs of organic matter or sunlight, degraded habitat, etc. Despite the complexity of these stressors, a large number of stream restoration projects focus primarily on physical channel characteristics. We show that this is not a wise investment if ecological recovery is the goal. Managers should critically diagnose the stressors impacting an impaired stream and invest resources first in repairing those problems most likely to limit restoration.

Historical channel movement and sediment accretion along the South Fork of the Iowa River

River valleys have been influenced by sediment derived from agricultural erosion and channel straightening intended to hasten flood routing. Post-settlement alluvium (PSA) has been little documented in tile-drained areas of the upper Midwest, where agricultural settlement began around 1850, and few soils are highly erodible. This study investigated channel movement and PSA accumulation along the South Fork of the Iowa River. Channels of the South Fork and tributary Tipton Creek were digitized using rectified aerial photographs taken in 1939 and 2002. Soil cores were collected along valley-crossing transects to determine PSA extent and thickness. Within 80 m (262 ft) of the South Fork, PSA averaged 0.78 m (30.7 in) thick and 85% frequency of occurrence. Beyond 80 m, PSA decreased below 50%. Within 43 m (141 ft) of Tipton Creek, PSA averaging 0.58 m thick occurred with 75% frequency. An estimated 9.2 × 10⁶ Mg (10.2 × 10⁶ tn) of PSA is stored along these valleys, representing 156.6 Mg ha⁻¹ (69.8 tn ac⁻¹) of soil eroded from uplands since settlement. The volume of PSA is equivalent to 11 mm (0.44 in) runoff from the watershed. The valley9s flood-storage capacity has been reduced by 5.1 × 10⁶ m³ (4,123 ac ft), considering pore space of the PSA. Modern flooding events are accordingly exacerbated by accretion of agricultural sediment, compared to presettlement river conditions. Channels were straightened in response to local flood events, which reduced stream length by 10% and hastened routing to the Iowa River. Design of river restoration projects should take account of fluvial processes and how these processes are responding to historical sedimentation and channel straightening.

Gestão Adaptativa e Sustentável para a Restauração de Rios: Parte II O Tema Desenho do Programa de Capacitação Social

This paper shows the evaluation performed in the Gramame river basin, in the South coastal region of Paraiba State, Brazil, referring to the application of the Thomson e Pepperdine (2003) methodology for analysis of the social capacity dimensions. The aim is to aid in the elaboration and evaluation of river restoration projects. Theme 4, concerning the design of the restoration program and its seven dimensions, is highlighted among the five themes that help understand the actors’ interaction in the basin. The results indicate paths of institutional macrochange which help consider ways of achieving shared objectives through sustainable adaptive management, among other major points

Assessment of the Effectiveness of a Constructed Compound Channel River Restoration Project on an Incised Stream

Compound channels are often constructed in restoration projects on rivers and streams that have been channelized or are deeply incised. This design allows for flow over a wider cross-sectional area during high flows and is expected to reduce both flow velocities and bed-shear stresses in the channel during high flows. Using a compound channel restoration project on Tassajara Creek as a case study, the effectiveness of a constructed compound channel in reducing channel velocities and bed-shear stresses during high flow events was tested in two ways. First, since this is an a posteriori analysis, postproject surveys and assessments of the project are used to demonstrate the geomorphic and ecological benefits of the constructed compound channel for reducing further channel incision, improving channel stability, and enhancing native riparian vegetation, while still providing conveyance capacity for design flood flows. Second, the effectiveness of a constructed compound channel in reducing channel velocities a...