Estuaries support critical ecological functions and processes. Restoration of estuarine habitats seeks to improve or repair physical conditions and processes, and to provide benefits to aquatic organisms. However, the trajectory of response for restoring degraded features can take years to achieve which results in uncertainty regarding when benefits to organisms will occur. We investigated the response of invertebrate assemblages and juvenile Chinook salmon foraging at hydrologically reconnected tidal wetland channels in the Columbia River estuary, U.S.A. We implemented a paired design where results from four restoration sites were compared to results from corresponding reference sites. Our analyses include hierarchical models to examine variations in salmon diet structure and three invertebrate community assemblages sampled within a wetland channel – benthic, upper water column, and wetland channel margin. Generalized additive models were used to predict total log-scale fish diet biomass as a function of spatial, temporal, and fish-level factors. Seasonality and location were primary sources of variation in the biological communities examined. We also found evidence of differences in invertebrate assemblages and fish foraging characteristics between restoration and reference sites in tidal wetlands, but the distinction between site-type (restoration, reference) was not a predominant factor and the effect of restoration differed by response variable. In our study, regardless of effect size, we found hydrologic reconnection of tidal wetlands provided opportunities for invertebrate production and fish foraging within three years of restoration actions, indicating the effectiveness of restoration may occur on short time scales.

Ecosystem restoration is a common tool for re-establishing ecosystem processes, structures, and functions to improve biodiversity and services in coastal and estuarine ecosystems. In the Salish Sea, salmon habitats have been fragmented, reduced in size, and diminished in quality, and the ecosystem processes that form and sustain these habitats have been degraded and disrupted as well. This loss is especially prevalent in estuaries, where up to 90% of former salmon habitat has been lost or compromised. Salmon species are integral to the identities and cultures of people in the Pacific Northwest, yet salmon abundances remain at historic lows, especially in urbanized areas. Recent investments in restoration are creating rearing habitat and repairing lost ecosystem function. However, restoration efforts in this region have largely proceeded at the site scale, with less attention to big-picture thinking regarding how restoration will effectively recover degraded or lost habitats for target species. As a result, no landscape-scale evaluation program exists, and the cumulative benefits of multiple interventions are unknown. We describe innovative methods for science synthesis related to the evaluation of cumulative effects of ecosystem restoration for Pacific salmon, using years of existing, but disparate data. Building from previous work on cumulative effects evaluation and incorporating a hierarchy of hypotheses approach, we propose using causal inference across numerous hypotheses in a framework to assess the cumulative benefits to Pacific salmon from multiple estuarine restoration projects. We present the framework as a method that can be used to address many complex questions and provide examples from the Salish Sea where the approach is being implemented. The framework draws on science synthesis from numerous fields and uses a hierarchy of hypotheses, causal analysis at multiple scales, and a new hierarchy of synthesis for assessing multiple lines of evidence documenting restoration effects on Pacific salmon. We propose causal inference to synthesize dissimilar data streams, in our case, to identify various manifestations of cumulative effects of restoration and benefits to salmon, and to further inform restoration and recovery planning. A unifying framework would allow for the detection of thresholds at which restoration provides measurable improvement and would greatly advance understanding of the effects of restoration on ecosystems.

A cohesive recovery strategy for Pacific salmon populations requires a shared conceptual foundation to coordinate management actions across jurisdictions and interests. We examined an estuary restoration program as a case study of a life history ecosystem framework proposed for Columbia River salmon conservation in 1999. The estuary program lacks an explicit framework to account for cross-scale connections to other salmon life stages. We propose the following conceptual foundation, composed of three guiding principles: (1) the estuary is a subsystem of a complex natural-cultural system connected by salmon life cycles; (2) a dynamic mosaic of estuarine habitats supports growth, ontogenetic development, and life history variations of salmon throughout the basin; and (3) physical and biological processes beyond the estuary limit opportunities for salmon life history expression within it. These principles require additional estuary performance indicators to coordinate water and fishery management programs and to adapt estuary restoration actions to a changing climate.

Tidal freshwater wetlands linking terrestrial, riverine, and saline habitats are critical areas for material processing and exchange. Once historically widespread, herbaceous marsh and forested tidal freshwater wetlands especially are now highly degraded worldwide. Additionally, quantitative assessments of hydrology and material exchange from these systems are lacking compared to lotic and estuarine (saltmarsh) habitats. Here we investigate macroinvertebrate and energy export from tidal marsh and forested wetlands and consider potential benefits from this ecological process to endangered Pacific salmon in a large tidal freshwater system, the Columbia River (USA). Macroinvertebrate (salmon prey) concentration, water velocity, and discharge were measured at several wetland habitat types (forested swamp, emergent marsh, and restored marsh). We used these data to compute prey flux and transport metrics. Then, applying literature values to calculate prey energy equivalents and juvenile salmon metabolic requirements, we estimated the potential energy subsidy available to juvenile salmon. Numerically, larval stages of aquatic insects were the predominant type of prey exported from the wetlands, with Diptera chironomid fly abundance exceeding other groups. Energetically, however, non-chironomid dipterans and hemipteran prey comprised most of energy transport due to their higher energetic content (energy density × mean weight). We determined the prey energy transported from the sampled tidal channels was sufficient to meet energetic needs of tens to thousands of juvenile salmon per day, depending on prey production and hydrography. The prey taxonomic composition differed among organisms exiting forested swamp, emergent marsh, and restored marsh habitats with corresponding differences in energy transport, but all habitat types supported similar numbers of juvenile salmon. We conclude that macroinvertebrate prey exported from varied tidal freshwater wetlands likely provide significant benefits to juvenile salmon over a larger ecological footprint than the wetland area would suggest.

To increase survival of diverse Columbia River salmon populations and life history types, we developed a landscape framework for habitat restoration to assess and reduce habitat fragmentation, and thereby improve habitat functions. For the last two decades, aquatic habitat has been restored in the Columbia River Estuary (U.S.A.) to aid salmon and steelhead ( Oncorhynchus spp.) listed under the Endangered Species Act. The 234‐km long estuary exhibits tidal to fluvial gradients in hydrology, sedimentology, and ecology, punctuated by large tributary rivers, cities, and land uses; it has lost two‐thirds of its historical floodplains and wetlands to development. Since 2009, an expert panel has assessed potential benefits of proposed restoration projects based on habitat “opportunity” (accessibility to juvenile salmon) and “capacity” (attributes supporting salmon production). These criteria favored large restoration projects located near the mainstem river, but they were insufficient for assessing a project's benefits due to geographic location relative to existing habitat. Our landscape framework applies the concept of restoring and conserving habitat “stepping stones” of appropriate size and location to benefit juvenile salmon growth and survival throughout their estuary residency and migration. We also compared contemporary and historical landscape conditions to identify restoration priorities. We improved our restoration project assessments by evaluating each project's benefits to juvenile salmon according to its location in the estuary relative to other habitat. Our approach operationalizes landscape ecology‐based decisions within the Columbia River Estuary for migratory salmon and is applicable to other large estuary systems with migratory aquatic species.

Ecological restoration programs in dynamic coastal environments can benefit from adaptive management, including an iterative process for identifying and addressing critical uncertainties. We highlight key developments under the three pillars that have increased the rate of restoration by the Columbia Estuary Ecosystem Restoration Program (CEERP) over 20 years: science, coordination, and management. We show how such programs can be institutionalized to ensure that estuary ecosystems are better understood, conserved, and restored. The principal conservation effort under CEERP is to reconnect historical floodplain wetlands to the mainstem. The program also supports other restoration actions that demonstrate a high potential to benefit ecosystem function and endangered salmon populations; however, there is greater uncertainty regarding these less‐utilized techniques. Through adaptive management, we address technical uncertainty regarding benefits to the environmental resource and programmatic uncertainty pertaining to decision‐making. Here, we examine three periods of CEERP growth to establish how complementary research and restoration actions have improved program outcomes over time. We highlight the tools and processes that were developed and integrated into the program to refine program strategy, improve project design, and maximize ecological benefits. CEERP supported 77 restoration projects and reconnected over 7,000 acres of floodplain habitat to the lower Columbia River between 2004 and 2021. Building on these successes, we outline current plans to better engage landowners and local communities, solicit new project types, and maintain enough flexibility within the program to adapt to new priorities.

Downstream passage for juvenile Chinook salmon Oncorhynchus tshawytscha (Walbaum) and steelhead Oncorhynchus mykiss (Walbaum) through the fish weir at Foster Dam, Oregon, was evaluated to assess the weir's efficacy as a long-term passage solution. Radio telemetry was used to estimate survival, passage and effectiveness for the fish weir, spillway and turbines. Survival of Chinook salmon through the fish weir varied by season and reservoir elevation (66%-87%), and passage proportions were low (8%-20%). Fish weir effectiveness was low to moderate (0.39-2.09). Steelhead survival was lower (57%-77%) but passed the fish weir in higher proportions (77%), and weir effectiveness was consistently high (2.96-5.49). The results indicate the existing fish weir will not be a suitable long-term passage solution for all species. However, because of the high passage proportions and effectiveness observed for steelhead, further development of the surface-flow concept appears to be promising for safely passing downstream-migrating fishes.

International efforts to restore degraded ecosystems will continue to expand over the coming decades, yet the factors contributing to the effectiveness of long-term restoration across large areas remain largely unexplored. At large scales, outcomes are more complex and synergistic than the additive impacts of individual restoration projects. Here, we propose a cumulative-effects conceptual framework to inform restoration design and implementation and to comprehensively measure ecological outcomes. To evaluate and illustrate this approach, we reviewed long-term restoration in several large coastal and riverine areas across the US: the greater Florida Everglades; Gulf of Mexico coast; lower Columbia River and estuary; Puget Sound; San Francisco Bay and Sacramento-San Joaquin Delta; Missouri River; and northeastern coastal states. Evidence supported eight modes of cumulative effects of interacting restoration projects, which improved outcomes for species and ecosystems at landscape and regional scales. We conclude that cumulative effects, usually measured for ecosystem degradation, are also measurable for ecosystem restoration. The consideration of evidence-based cumulative effects will help managers of large-scale restoration capitalize on positive feedback and reduce countervailing effects.

In intertidal wetlands, habitat access by out-migrating juvenile anadromous fishes, such as salmon (Oncorhynchus spp.), is influenced by both physical and biological factors. Physical limits are set by inundation patterns and water quality parameters, while biological bounds are determined by species-specific migration timing and seasonal residency behaviors. We developed a new metric called the fish habitat opportunity index to quantify the total time (h) and volume-time (m3-h) per calendar year that salmon could access a given wetland, based on periods of inundation (volume) and seasonal migration period (time). The basic assumption of the index is that the volume of water inundating a restored wetland and the amount of time the wetland is inundated are both positively related to ecological benefits to juvenile salmon in terms of foraging success, growth, condition, and refuge from predators. We tested this index using data collected at a reconnected tidal freshwater wetland area in the lower Columbia River and estuary during 2006–2009. We found the wetland to be accessible to different salmon species for different lengths of time and periods of the year. On average, Chum Salmon (O. keta) had remarkably consistent opportunities to use wetland marsh habitat over the four years sampled, while opportunities were more variable for Chinook Salmon (O. tshawytscha), and Coho Salmon (O. kisutch). Inundation varied nonlinearly with tidal height. Fish had access to the productive marsh edge for approximately 40–50% of the time during out-migration periods. The fish habitat opportunity index is applicable to wetland systems throughout the tidal-fluvial continuum. It provides a metric for assessing fish habitat opportunity that is more realistic than simple wetted-area calculations or species presence/absence data. Most importantly, the fish habitat opportunity index affords a method for a priori comparison among potential restoration sites to help resource managers predict the likely relative effects on habitat opportunity from restoration aimed at benefiting juvenile anadromous fishes. Maximizing the fish habitat opportunity index should positively affect fish populations that use tidal-fluvial wetlands as vital habitats in their life cycle.

This article documents lessons learned from experiences in NASA's Apollo and Skylab Programs. These lessons are valuable for future missions, NASA exploration, and commercial flights. The article describes the author's experiences as an electrical engineer supporting design, testing, and mission operations during various Apollo, Skylab, and Apollo Soyuz Test Project missions. Incidents include the Apollo 13 oxygen tank explosion, the Apollo 14 docking close call, the Apollo 15 propulsion system electrical short, the Apollo 10 inadvertent lunar module abort, the Skylab 4 loss of control for entry, the Apollo Soyuz Test Project crew ingestion of toxic propellant, the Apollo 7 AC bus short, and the Apollo 16 Lunar Rover Vehicle anomalies. Lessons from two incidents on uncrewed flights, the Apollo 4 launch pad instrumentation electrical noise and the Mars Viking test stand electrical noise problem, are also included because of their direct relevance to human spaceflight.

This paper describes a methodology for estimating the take of upstream migrating adult chum salmon (Oncorhynchus keta) caused by confined underwater rock blasting. Because these fish are listed under the Endangered Species Act, it is unlawful to take (i.e., harm, capture, collect, injure, kill, etc.) them without a federal permit. In the permit for an underwater blasting project to deepen a 2 km section of the Columbia River navigation channel linking Portland, Oregon, to the Pacific Ocean, regulators defined take as the mortality of adult chum salmon due to underwater blasting. They required monitoring to estimate take to track compliance with the permit. Conventional predictive models of fish mortality from underwater blasting depend on data about the explosive charges; however, such data for this project were not available for proprietary reasons. Therefore, an innovative approach had to be conceived. The dose-exposure-response methodology we developed provided an unobtrusive, science-based methodology for monitoring and near real-time reporting of adult chum salmon take. We applied the methodology for 99 blasting events from November 1, 2009, through February 5, 2010, in the lower Columbia River (rkm 139-141). The mean absolute peak pressure in underwater sound generated by blast events was 151,685 Pa (22 psi) at a range of 42.7 m. The estimated cumulative take for the project was 0.126 adult chum salmon, far below the 10-fish mortality limit regulators set for the project. We propose that this dose-exposure-response methodology be considered wherever underwater blasting has the potential to have an adverse effect on important fish species.

The Consortium for Execution of Rendezvous and Servicing Operations (CONFERS) is an industry-led initiative with initial seed funding provided by the Defense Advanced Research Projects Agency (DARPA) that aims to leverage best practices from government and industry to research, develop, and publish non-binding, consensus-derived technical and operations standards for On-Orbit Servicing (OOS) and Rendezvous and Proximity Operations (RPO). As part of the CONFERS effort, the University of Southern California’s (USC) Space Engineering Research Center (SERC) conducted research into existing RPO methodologies and practices and OOS methodologies through literature review and interviews with practitioners. Following the first year of analytical input focused solely on RPO, the second year’s activities have focused further into the full extent of attributes for satellite servicing and in-space docking (OOS). USC’s focus was to develop a taxonomy of functions and attributes related to all aspects of technical elements and techniques required for past/current/anticipated OOS missions. A taxonomy database was created that allowed various key elements to be broken down into quantifiable data within common categories. Following the taxonomy creation, working with the Space Infrastructure Foundation (SIF) a review of existing standards in space along with other industries were analyzed and compared for possible matches. This standards gap analysis focused primarily from the end of the RPO maneuver to the point of physical contact or action between two spacecraft. These comparisons were then used to recommend where gaps in standards exist and where it might be most beneficial to create new ones, enabling spacecraft of various shapes and sizes to safely execute various OOS operations, and spur the industry between customers and providers. The field of space servicing is a rapidly growing field, with governments and numerous private entities developing robotic systems for mission extension vehicles and satellite repair. With an increased number of servicing missions forthcoming, a system of guidelines and standards on how to effectively and safely design on-orbit servicing activities is a next natural step to enable the expansion of this burgeoning industry.

The transport of terrestrial plant matter into coastal waters is important to regional and global biogeochemical cycles, and methods for assessing and predicting fluxes in such dynamic environments are needed. We investigated the hypothesis that upon reconnection of a floodplain wetland to its mainstem river, organic matter produced in the wetland would reach other parts of the ecosystem. If so, we can infer that the organic matter would ultimately become a source for the food web in the mainstem river and estuary. To accomplish this, we adapted numerical hydrodynamic and transport modeling methods to estimate the mass of particulate organic matter (POM) derived from the annually senescent aboveground parts of herbaceous marsh plants (H-POM). The Finite-Volume Community Ocean Model (FVCOM), parameterized with flow, tide, and aboveground biomass data, simulated H-POM mobilization from fluid shear stress during tidal exchange, flooding, and variable river flow; entrainment into the water column; transport via channel and overland flow; and entrapment when wetted surfaces dry. We examined export from a recently reconnected, restoring tidal emergent marsh on the Grays River, a tributary to the Columbia River estuary. Modeling indicated that hydrologically reconnecting 65 ha at the site resulted in export of about 96 × 103  kg of H-POM, primarily during pulsed storm flooding events in autumn and early winter. This exported mass amounted to about 19% of the summer peak aboveground biomass measured at the site. Of that 19%, about 48% (47 × 103  kg) was deposited downstream in the Grays River and floodplain wetlands, and the remaining 52% (50 × 103  kg) passed the confluence of the Grays River and the mainstem estuary located about 7 km from the study site. The colonization of the restoring study site largely by nonnative Phalaris arundinacea (reed canarygrass) may have resulted in 18-28% lower H-POM mobilization than typical marsh plant communities on this floodplain, based on estimates from regional studies of marshes dominated by less recalcitrant species. We concluded that restored floodplain wetlands can contribute significant amounts of organic matter to the estuarine ecosystem and thereby contribute to the restoration of historical trophic structure.

This article presents a novel method for coarsely modeling space flight risk in the absence of vehicle-specific data. Risk and usage rates for several different modes of transportation (including space flight) and adventure sports activities (mountaineering, skydiving, and SCUBA diving) were correlated, and a line of best fit equation was derived. The strong, inverse correlation between number of fatal accidents per trip (i.e. risk) and number of trips per year (i.e. usage) (r = −0.90, p < 0.01), and the strong correlation between number of fatalities per participant and number of participants per year (r = −0.93), suggest that risk and usage may be inherently correlative, even across distinct modalities. As such, this quantitative relationship can be used to supplement traditional analysis techniques and serve as a sanity check for expert opinion—particularly during the early stages of vehicle development, when quantitative data is limited and cannot readily support alternative risk prediction techniques. In addition, this general relationship can provide an additional benchmark for tracking performance throughout the operational lifetime of a program, and offers a unique perspective for comparing the relative risk of spaceflight to more commonly experienced terrestrial activities.

Approximately 16% of the world’s electricity and over 80% of the world’s renewable electricity is generated from hydropower resources, and there is potential for developing significantly more new hydropower capacity. In practice, however, optimizing the use of potential hydropower resources is limited by various factors, including environmental effects and related mitigation requirements. That is why hydropower regulatory requirements frequently call for targets to be met regarding fish injury and mortality rates. The sensor fish (SF) is a small autonomous sensor package that can be deployed through complex hydraulic structures, such as a turbine or spillway, to collect high resolution measurements that describe the forces and motions that live fish would encounter. The Hydropower Biological Evaluation Toolset (HBET), an integrated suite of science-based tools, is designed to use the SF (implemented) and other tools (to be implemented in the future) to characterize the hydraulic conditions of hydropower structures and provide quantitative estimates of fish injury and mortality rates resulting from exposure to various physical stressors including strike, pressure, and shear. HBET enables users to design new studies, analyze data, perform statistical analyses, and evaluate biological responses. It can be used by researchers, turbine designers, hydropower operators, and regulators to design and operate hydropower systems that minimize ecological impacts in a cost-effective manner. In this paper, we discuss the technical methodologies and algorithms implemented in HBET and describe a case study that illustrates its functionalities.

We describe a process for evaluating proposed ecosystem restoration projects intended to improve survival of juvenile salmon in the Columbia River estuary (CRE). Changes in the Columbia River basin (northwestern USA), including hydropower development, have contributed to the listing of 13 salmon stocks as endangered or threatened under the U.S. Endangered Species Act. Habitat restoration in the CRE, from Bonneville Dam to the ocean, is part of a basin-wide, legally mandated effort to mitigate federal hydropower impacts on salmon survival. An Expert Regional Technical Group (ERTG) was established in 2009 to improve and implement a process for assessing and assigning "survival benefit units" (SBUs) to restoration actions. The SBU concept assumes site-specific restoration projects will increase juvenile salmon survival during migration through the 234 km CRE. Assigned SBUs are used to inform selection of restoration projects and gauge mitigation progress. The ERTG standardized the SBU assessment process to improve its scientific integrity, repeatability, and transparency. In lieu of experimental data to quantify the survival benefits of individual restoration actions, the ERTG adopted a conceptual model composed of three assessment criteria-certainty of success, fish opportunity improvements, and habitat capacity improvements-to evaluate restoration projects. Based on these criteria, an algorithm assigned SBUs by integrating potential fish density as an indicator of salmon performance. Between 2009 and 2014, the ERTG assessed SBUs for 55 proposed projects involving a total of 181 restoration actions located across 8 of 9 reaches of the CRE, largely relying on information provided in a project template based on the conceptual model, presentations, discussions with project sponsors, and site visits. Most projects restored tidal inundation to emergent wetlands, improved riparian function, and removed invasive vegetation. The scientific relationship of geomorphic and salmonid responses to restoration actions remains the foremost concern. Although not designed to establish a broad strategy for estuary restoration, the scoring process has adaptively influenced the types, designs, and locations of restoration proposals. The ERTG process may be a useful model for others who have unique ecosystem restoration goals and share some of our common challenges.

We implemented and institutionalized an adaptive management (AM) process for the Columbia Estuary Ecosystem Restoration Program, which is a large‐scale restoration program focused on improving ecosystem conditions in the 234‐km lower Columbia River and estuary. For our purpose, “institutionalized” means the AM process and restoration programs are embedded in the work flow of the implementing agencies and affected parties. While plans outlining frameworks, processes, or approaches to AM of ecosystem restoration programs are commonplace, their establishment for the long‐term is not. This article presents the basic AM process and explains how AM was implemented and institutionalized. Starting with a common goal, we pursued a well‐understood governance and decision‐making structure, routine coordination and communication activities, data and information sharing, commitment from partners and upper agency management to the AM process, and meaningful cooperation among program managers and partners. The overall approach and steps to implement and institutionalize AM for ecosystem restoration explained here are applicable to situations in which it has been incomplete or, as in our case, the restoration program is just getting started.

Fish can be injured or killed during turbine passage. This paper reports the first in-situ evaluation of hydraulic conditions that fish experienced during passage through Francis turbines using an autonomous sensor device at Arrowrock, Cougar, and Detroit Dams. Among different turbine passage regions, most of the severe events occurred in the stay vane/wicket gate and the runner regions. In the stay vane/wicket gate region, almost all severe events were collisions. In the runner region, both severe collisions and severe shear events occurred. At Cougar Dam, at least 50% fewer releases experienced severe collisions in the runner region operating at peak efficiency than at the minimum and maximum opening, indicating the wicket gate opening could affect hydraulic conditions in the runner region. A higher percentage of releases experienced severe events in the runner region when passing through the Francis turbines than through an advanced hydropower Kaplan turbine (AHT) at Wanapum Dam. The nadir pressures of the three Francis turbines were more than 50% lower than those of the AHT. The three Francis turbines had much higher magnitudes and rates of pressure change than the AHT. This study provides critical information on hydraulic conditions and fish passage information of Francis turbines, which can help guide future laboratory studies of fish passing through Francis turbine, design fish-friendly turbines, and optimize the operation of existing turbines for better fish passage conditions.