Hydro-morphological parameters generate lifespan maps for stream restoration management

Numerous artificial side channels have been constructed in British Columbia and the Pacific Northwest to compensate for habitat loss from floodplain development. We reviewed data from published studies on natural and restored side channel habitats to determine how design features influence productive capacity for juvenile coho salmon Oncorhynchus kisutch. Average density and biomass of coho salmon parr were significantly higher in stream-type side channels (3.4 parr/m2 and 8.01 g/m2, respectively) than in pond-type side channels (0.8 parr/m2 and 2.37 g/m2). Although total parr biomass was three times higher in stream-type side channels, average parr weight was 47% lower, suggesting greater density-dependent limitation of growth from higher recruitment of juveniles to stream-type habitats. Parr abundance declined from late summer to early spring in both side channel types but appeared to decrease more quickly in stream-type side channels, suggesting greater self-thinning in stream-type habitat from mortality or immigration to slower pond or main-stem habitat as fish sought lower velocities for overwintering. Fish density in a single off-channel complex that contained both stream and pond habitats (fish were able to move between habitats) was also higher in stream habitats, although fish were significantly larger in pond habitats than in stream habitats. Parr density in stream-type side channels was constant with increasing channel size, whereas density in pond-type side channels was a decreasing function of side channel area. Smolt production data were more limited and variable, and production was not significantly different between stream- and pond-type side channels. Smolt density (smolts produced/m2 of channel habitat) was also a decreasing function of total side channel area, indicating that the optimal side channel habitat size (or pond size within a side channel complex) was below 5,000–10,000 m2. Side channels that incorporate a diversity of flowing- and standing-water areas are most likely to provide the variety of habitats (i.e., spawning, summer rearing, and overwintering) required by salmonids to complete their life cycle.

The Southeast Coast Network (SECN) stream habitat monitoring protocol collects data to give park resource managers insight into the status of and trends in stream and near-channel habitat conditions (McDonald et al. 2018a). Wadeable stream assessments are currently implemented at the five SECN inland parks with wadeable streams. These parks include Horseshoe Bend National Military Park (HOBE), Kennesaw Mountain National Battlefield (KEMO), Ocmulgee Mounds National Historical Park (OCMU), Chattahoochee River National Recreation Area (CHAT), and Congaree National Park (CONG). Streams chosen for assessment were specifically targeted for management interest (e.g., trail erosion issues and upstream urban development) or to provide a context for similar-sized stream(s) within the park or network (McDonald and Starkey 2019a). The objectives of the SECN stream habitat monitoring protocol are to: • Determine status of upstream watershed characteristics (basin morphology) and trends in land cover that may affect stream habitat; • Determine the status of and trends in benthic and near-channel habitat in selected wadeable stream reaches (e.g., bed sediment, geomorphic channel units [GCUs], and large woody debris [LWD]); and • Determine the status of and trends in cross-sectional morphology, longitudinal gradient, and sinuosity of selected wadeable stream reaches. On September 27, 2017, data were collected at Ocmulgee Mounds National Historical Park (OCMU) to characterize the in- and near-channel habitat on a permanently monumented reach on Walnut Creek (OCMU001). These data, along with in-office analysis of remotely-sensed geographic information system (GIS) data, are presented in this report to describe and compare the watershed-, reach-, and transect-scale characteristics of OCMU001 to selected third-order streams at Chattahoochee River National Recreation Area (CHAT001 and CHAT013) and Kennesaw Mountain National Battlefield Park (KEMO001 and KEMO002). Reach OCMU001’s watershed (Walnut Creek) has low slope/relief and is covered mostly by forest and agricultural pasture. The major defining characteristics of the stream were the presence of floodplains, natural levees, lack of riffle habitat, and homogeneous channel slope throughout the reach. Though the majority of the watershed lies in the Appalachian Piedmont physiographic province, the OCMU001 reach of Walnut Creek lies in the Upper Coastal Plain and is a low energy, depositional environment which is subject to regular flooding and slow post-flood draining. The channel surveyed at OCMU001 is smaller than expected, given the large size of its watershed. The small channel size is interpreted as evidence that the majority of flood waters that come through Ocmulgee Mounds NHP by way of Walnut Creek do not follow this flow path. Alternatively, flood waters are diverted away from the hillslope, into the wetlands to the west of OCMU001 and into a power line right-of-way east of OCMU001, through a series of flood chutes and side channels. It is suggested that discharge monitoring stations be installed at the railroad bridge that crosses Walnut Creek (upstream of OCMU001), just upstream of OCMU001, and immediately downstream of OCMU001 to determine the proportion of flow that bypasses the channel at OCMU001 and to determine how much floodwater enters OCMU001 through flood chutes and side channels. Though the reach had a high abundance of large woody debris (LWD), based on the results of the pebble count and the type/distribution of the geomorphic channel unit (GCU) within the reach, in-stream habitat within the surveyed stream was classified as “poor to fair.” These classifications are generalized interpretations of in-stream habitat and additional work is needed to determine how flow (e.g., flashiness of flow and baseflow conditions), water quality, and in-stream physical characteristics affect biodiversity and stream health at Ocmulgee Mounds NHP. Given the complex hydrologic setting of OCMU

Stream restoration, involving both in-stream and riparian techniques, was conducted on an impaired stretch of the Cacapon River, West Virginia. Fish and aquatic macroinvertebrate communities were sampled before, during, and after restoration at the restoration site and four other sites (two impaired, two natural) to determine the success of the restoration project. Overall, bluntnose minnows (Pimephales notatus) were the most abundant fish, and riffle beetles (Stenelmis sp.) were the most abundant macroinvertebrates collected. Both communities were negatively impacted by the restoration efforts in the short-term, but recovered quickly. Fish communities returned roughly to the state observed pre-restoration. Macroinvertebrate communities increased in health post-restoration; they resembled other impaired stretches prior to restoration, and resembled natural stretches following restoration. Local macroinvertebrate abundance, in particular, responded quickly. Therefore, macroinvertebrates were stronger indicators of site health than were fish in the Cacapon River.;Centrarchid nesting behavior and response to perceived harm were assessed using several environmental variables, collected from nest sites and random sites during the summer of 2010. A priori general linear models were generated to explain nest site selection, nest success, and response to perceived harm based on the environmental variables. Overall, four species of centrarchids were observed nesting: longear sunfish (Lepomis megalotis), redbreast sunfish (Lepomis auritus), rock bass ( Ambloplites rupestris), and smallmouth bass (Micropterus dolomieu). All four species nested in habitat significantly different from random sites in the river, and therefore were selecting for specific habitat. Longear sunfish also nested in habitat significantly different from the other three species. The differences in site selection were largely determined by distance to other centrarchid nests, distance to in-stream cover objects, and water velocity. Human observer-induced threat response in longear sunfish was influenced by male size, water velocity, and distance to cover. Due to a general lack of nest reuse and commonality of nests located in substantial water current, it is likely that female choice and protection from predators are driving site selection in male centrarchids more than minimization of energy expenditure.

Between 60 and 80 of the cumulative channel length in mountainous areas, such as eastern Kentucky, comprises headwater streams. Surface mining, and in particular mountaintop mining with its associated valley fills, poses a significant environmental risk to aquatic and terrestrial life through the direct conversion of headwater streams to uplands and the associated degradation of downstream receiving waters. In light of the importance of headwater streams, development of practical stream restoration techniques for mined lands is crucial in order to restore impacted headwater stream systems. Stream restoration efforts are predominately focused on waterways in agricultural and urban settings with a relatively limited number of projects on mined lands. Often employing natural channel design (NCD) techniques, stream restoration practitioners utilize reference reaches to design new channels with the appropriate dimensions, patterns, and profiles. The ability to successfully restore or recreate streams on mined lands is linked to the restoration of the streams' watershed, including uplands and riparian areas, and stream channel.

<em>Abstract</em>.—Catfishes are important in freshwater ecosystems not only as consumers, but also as essential partners in symbiotic relationships with other organisms. Freshwater mollusks are among the many organisms that have interactions with catfishes. For example, ictalurids are hosts for larvae of several native freshwater mussel species. The larvae, which attach briefly to gills or fins of fish to complete their development to the free-living juvenile stage, disperse via upstream and downstream movement of host fish. In turn, freshwater mussels serve as a food source for some catfish species while other catfish species may use spent mussel shells for habitat. Ictalurids also benefit from the conservation status of many freshwater mussel species. Federal and state laws protecting these invertebrates can preserve water quality and habitat and, at times, provide incentives and funding for conservation and restoration of stream and riparian habitats.

Restoration of streams degraded by urbanization has usually been attempted by enhancement of instream habitat or riparian zones. Such restoration approaches are unlikely to substantially improve instream ecological condition because they do not match the scale of the degrading process. Recent studies of urban impacts on streams in Melbourne, Australia, on water chemistry, algal biomass and assemblage composition of diatoms and invertebrates, suggested that the primary degrading process to streams in many urban areas is effective imperviousness (EI), the proportion of a catchment covered by impervious surfaces directly connected to the stream by stormwater drainage pipes. The direct connection of impervious surfaces to streams means that even small rainfall events can produce sufficient surface runoff to cause frequent disturbance through regular delivery of water and pollutants; where impervious surfaces are not directly connected to streams, small rainfall events are intercepted and infiltrated. We, therefore, identified use of alternative drainage methods, which maintain a near-natural frequency of surface runoff from the catchment, as the best approach to stream restoration in urban catchments and then used models of relationships between 14 ecological indicators and EI to determine restoration objectives. Ecological condition, as indicated by concentrations of water-quality variables, algal biomass, and several measures of diatom and macroinvertebrate assemblage composition, declined with increasing EI until a threshold was reached (EI = 0.01–0.14), beyond which no further degradation was observed. We showed, in a sample catchment, that it is possible to redesign the drainage system to reduce EI to a level at which the models predict detectable improvement in most ecological indicators. Distributed, low-impact design measures are required that intercept rainfall from small events and then facilitate its infiltration, evaporation, transpiration, or storage for later in-house use.

Riparian zones play a major role in the structure and function of headwater stream ecosystems. Inputs of leaf litter from riparian zones are the primary energy source for secondary production in these streams and inputs of large woody debris (LWD) help shape stream habitat. Riparian zones of Appalachian streams were degraded by past timber harvest activities. Streamside management zones (SMZs) now protect the riparian zone by limiting timber harvest activities near streams. The objective of this study was to examine aquatic-terrestrial linkages and how habitat and food resources influence brook trout ( Salvelinus fontinalis) populations in Appalachian streams. LWD was experimentally added to eight streams in the Middle Fork River watershed, Randolph Co., WV to determine if stream habitat and prey availability could be enhanced. Stream habitat was assessed and brook trout populations were monitored for one year prior to, and three years following habitat manipulations. Invertebrate drift and brook trout diets were collected to determine the effects of LWD additions on trophic dynamics and to assess the importance of terrestrial invertebrate prey to brook trout energetics. LWD additions had little effect on stream habitat by three years post-manipulation. Brook trout populations fluctuated over time, but did not show a consistent increase. Although, the number of locations where leaf litter was stored increased, invertebrate drift did not increase following the addition of LWD. Likewise, prey consumption by brook trout was not influenced by the LWD additions, but diet composition showed a shift with the proportion of the diet comprised of the shredder functional feeding group increasing by two years post-habitat manipulation. Terrestrial invertebrates comprised a large portion of the yearly consumed energy by brook trout. The results of this study illustrate the important linkage between terrestrial and aquatic systems in the trophic dynamics of headwater streams. However, the duration of the study was likely not long enough to detect significant changes in stream habitat and brook trout populations due to LWD additions. The benefits of these habitat manipulations may not be realized for several more years. These initial results may help guide resource managers in future stream restoration efforts.

Riparian vegetation distribution patterns and diversity relative to various fluvial geomorphic channel patterns, stream bank stabilization methods, and stream flow processes are described and interpreted for selected nature-friendly small stream bank protection of Goesan, central Korea. Idong Stream Pilot Project, which began in May 2003 and finished in December 2003, was selected to develop effective methods which was nature-friendly stream bank protection. The project aim to maintain or increase stream bank stabilization ecosystem goods and services while protecting downstream and stream bank ecosystem. A number of protecting methods which were a Flight of fieldstone, Vegetation block, Green river block, Stone net, Green environment block, Eco friendly cobble, Vegetation mat and Geo-green cell and Firefly block were applied on the bank of Idong stream. The stream sites have been monitored about vegetation conditions each method in 2007. We selected six points to separately investigate in left and right bank. The main purpose of this study was to find out suitable methods and to improve stream restoration techniques for ecosystem. On the stream bank, H environment block method (9.7) was the highest average of vegetation coverage and Firefly block method (3.87) was the lowest average in applied methods.

Emergent cutthroat trout fry (Salmo clarki) were observed in the margins, backwaters, and side channels, collectively called "lateral habitats," of three study streams with different riparian vegetation. Most fry remained in these lateral habitats until the end of their first summer. The abundance of cutthroat fry was proportional to the area of lateral habitat in each of the study streams. Average size and growth rate of fry were related to the effect of site elevation on stream temperature and the influence of riparian vegetation on the availability of invertebrate food. Lateral habitats are characterized by slow, shallow-water, abundant detritus and benthic invertebrate assemblages of high density. Stream margins and backwaters provide gradients of depth and velocity, cover, and access to food that are appropriate to the habitat requirements of fry. Because fry populations are closely related to the abundance and quality of lateral habitats in small streams, these habitats should be included in the assessment of habitat requirements of cutthroat trout.

Historically the Pearl River received large amounts of municipal sewage and industrial wastes. The river was ultimately reclaimed by installation of primary and secondary treatment facilities for both effluents. No violations of state or federal water quality criteria were observed in the 10-year period subsequent to installation of treatment facilities. Positive results of pollution abatement and river reclamation were: (1) an increase in clean water species of fishes and invertebrates, (2) a decrease in pollution tolerant species such as the annelid Tubifex, (3) reestablishment of unionid mussel populations in the reclaimed river segment, and (4) increased growth rates for some species of fishes.

Long-term habitat degradation has increased public recognition of the need for watershed and stream habitat restoration. With such recognition is the demand for accountability, but the effects of restoration and recovery of watersheds are complex and long-term. A monitoring program that provides sufficient information to evaluate the effectiveness of these efforts will be expensive. A pulsed monitoring strategy that consists of a series of short-term (3–5 years), high-intensity studies separated by longer periods (10–15 years) of low-density data collection can provide an effective means of implementing a long-term monitoring program with a reasonable degree of success and cost.

The primary focus of many in-stream restoration projects is to enhance habitat diversity for salmonid fishes, yet the lack of properly designed monitoring studies, particularly ones with pre-restoration data, limits any attempts to assess whether restoration has succeeded in improving salmonid habitat. Even less is known about the impacts of fisheries-related restoration on other, non-target biota. We examined how restoration aiming at the enhancement of juvenile brown trout (Salmo trutta L.) affects benthic macroinvertebrates, using two separate data sets: (1) a before-after-control-impact (BACI) design with three years before and three after restoration in differently restored and control reaches of six streams; and (2) a space-time substitution design including channelized, restored, and near-natural streams with an almost 20-year perspective on the recovery of invertebrate communities. In the BACI design, total macroinvertebrate density differed significantly from before to after restoration. Following restoration, densities decreased in all treatments, but less so in the controls than in restored sections. Taxonomic richness also decreased from before to after restoration, but this happened similarly in all treatments. In the long-term comparative study, macroinvertebrate species richness showed no difference between the channel types. Community composition differed significantly between the restored and natural streams, but not between restored and channelized streams. Overall, the in-stream restoration measures used increased stream habitat diversity but did not enhance benthic biodiversity. While many macroinvertebrates may be dispersal limited, our study sites should not have been too distant to reach within almost two decades. A key explanation for the weak responses by macroinvertebrate communities may have been historical. When Fennoscandian streams were channelized for log floating, the loss of habitat heterogeneity was only partial. Therefore, habitat may not have been limiting the macroinvertebrate communities to begin with. Stream restoration to support trout fisheries has strong public acceptance in Finland and will likely continue to increase in the near future. Therefore, more effort should be placed on assessing restoration success from a biodiversity perspective using multiple organism groups in both stream and riparian ecosystems.

River systems in the mountain western USA have been shaped by the presence of beavers for millennia. However, beavers have been extirpated from the landscape in many places, leading to excessive stream incision and streambank erosion. One common strategy to mitigate this issue is to deploy beaver dam analogue (BDAs) as a stream restoration technique. Although BDAs are intended to reduce erosion and stream incision, few studies directly document the impact of BDAs on stream channel geomorphology. This study, therefore, assesses how a complex of five BDAs along a 150 m long stream reach in Red Canyon Ranch near Lander, WY impacts stream bank erosion and deposition and channel evolution over a 1‐year period post‐installation. Relative to control locations not impacted by BDAs, the BDA reach showed greater spatial heterogeneity in erosion and deposition patterns than control locations, as well as less overall erosion. However, each BDA had unique effects on channel morphology. Large amounts of deposition were found at the most upstream BDA remaining after the first year at both inner and outer meander locations. High flow events created breaches that likely produced significant stream bank erosion observed immediately downstream of the BDA complex. From a design standpoint, the only BDAs that remained after a year were those built around fence posts inserted into the stream bed with a percussion fence post driver. Overall, our short‐term data indicate that BDAs can be successfully used as a stream restoration practice to reduce stream bank erosion and increase channel geomorphological heterogeneity.

In 2000, the Confederated Tribes of the Umatilla Indian Reservation (CTUIR) Fisheries Habitat Program implemented stream habitat restoration and protection efforts in the Walla Walla River Basin with funding from Bonneville Power Administration (BPA). The objective of these efforts is to protect and restore habitat critical to the recovery of weak or reintroduced populations of salmonid fish. Six projects, two on Couse Creek, two adjacent properties on Blue Creek, one on Patit Creek, and one property on the mainstem Walla Walla River were part of the exercise. Several thousand native plants as bare-root stock and cuttings were reintroduced to the sites and 18 acres of floodplain corridor was seeded with native grass seed. Pre and post-project monitoring efforts were included for all projects, incorporating methodologies from CTUIR's Draft Monitoring Plan.

High spatial and temporal resolution models are essential for understanding future climate impacts and developing effective climate resilience plans. However, existing regional and global river models often lack the resolution needed to accurately capture local conditions. This study uses a series of high-resolution models, including the Regional Arctic System Model, mizuRoute, and the river basin model, to analyze Arctic and sub-Arctic Alaskan hydrology. We compare a historical baseline (1991–2020) with six midcentury (2035–64) futures: two pseudo–global warming scenarios based on historical meteorology and four direct dynamically downscaled global climate models. The six futures reveal significant uncertainty in future annual discharge and peak flows, although a widespread increase in discharge during April (+63%) and October (+31%) is consistently shown across models. Projected increases in rain and shifting weather patterns lead to a transition from snow to rain in spring and autumn, reducing the fraction of snowmelt contributing to river discharge. Rising evapotranspiration moderates discharge changes, particularly in autumn, by offsetting precipitation increases. Average summer river temperatures are projected to increase by approximately 1.5°C, doubling the number of river segments that experience 18°C days, a critical threshold for salmon survival, and intensifying the heat flux to the ocean adding an average of 3.3 × 1012 MJ yr−1. These changes in the hydrologic cycle could profoundly impact riverine and oceanic ecosystems, posing substantial challenges to communities reliant on these environments. Significance Statement The purpose of this study is to enhance our understanding of the midcentury climate change impacts on the Alaskan hydrologic cycle. In all six of the potential future scenarios, river flows in spring and autumn are predicted to increase and river temperatures are projected to be warmer throughout the year. These changes are significant as higher river temperatures could jeopardize fish survival. Additionally, the combined effect of increased river water and higher temperatures during spring and autumn will contribute more heat to the ocean, possibly reducing nearshore sea ice. This is crucial because many communities depend on rivers and sea ice for transportation and subsistence activities.