River Miles Research Articles

Deep learning of estuary salinity dynamics is physically accurate at a fraction of hydrodynamic model computational cost

AbstractSalinity dynamics in the Delaware Bay estuary are a critical water quality concern as elevated salinity can damage infrastructure and threaten drinking water supplies. Current state‐of‐the‐art modeling approaches use hydrodynamic models, which can produce accurate results but are limited by significant computational costs. We developed a machine learning (ML) model to predict the 250 mg L−1 Cl− isochlor, also known as the “salt front,” using daily river discharge, meteorological drivers, and tidal water level data. We use the ML model to predict the location of the salt front, measured in river miles (RM) along the Delaware River, during the period 2001–2020, and we compare predictions of the ML model to the hydrodynamic Coupled Ocean–Atmosphere‐Wave‐Sediment Transport (COAWST) model. The ML model predicts the location of the salt front with greater accuracy (root mean squared error [RMSE] = 2.52 RM) than the COAWST model does (RMSE = 5.36); however, the ML model struggles to predict extreme events. Furthermore, we use functional performance and expected gradients, tools from information theory and explainable artificial intelligence, to show that the ML model learns physically realistic relationships between the salt front location and drivers (particularly discharge and tidal water level). These results demonstrate how an ML modeling approach can provide predictive and functional accuracy at a significantly reduced computational cost compared to process‐based models. In addition, these results provide support for using ML models in operational forecasting, scenario testing, management decisions, hindcasting, and resulting opportunities to understand past behavior and develop hypotheses.

Cold Roses

Cold Roses Juliana Gray (bio) Vermont’s Green Mountains jut into the horizon like the dramatic, unlikely slopes I drew as a child. They seem so close, as if walking a few miles in their direction I might suddenly bang my knee against the incline. That illusion—that the mountains were only a mile or so around the bend—was unshakable during my drive here. Now, walking the hills above town, I feel it again. I take a few pictures, but the February day is bright, so I mostly capture sun flares against dark hills. I’m at an artists’ residency, and I should be writing in my cozy little studio. But it’s a rare sunny day, and I’ve been eating rich dining hall food with no exercise. Stretching my legs in sun, luxuriating like a cat, I strip off my coat and tuck my phone into my back pocket, earbuds connecting me to a true crime podcast for company. Back in my room, I post my bad pictures on Facebook and make a joke about how much I’ve missed my murder podcasts. “A lovely place for murder!” a friend comments. Amused, curious, I look online. And in no time at all, I find one. ________ Jodie Whitney was 35, with brown hair and a toothy smile. She worked at Stoweflake Mountain Resort in Stowe; she was married, and had a three-year-old daughter. On May 24, 2004, her husband reported her missing, saying he last saw her that morning before he left for work. She never showed up at the resort that day, and she never came home. Her Jeep was found behind a barn, not far from her house. Jodie wasn’t in it. ________ The podcast I had listened to during my walk was indeed about a murder, or rather, a likely murder. Eight-year-old Relisha Rudd was living with her mother in a homeless shelter; Relisha was taken by a friend, a man the mother trusted. She didn’t, at first, perceive that her child was in danger, and didn’t report her missing. Relisha was Black, so it was somewhat unusual to hear her case covered [End Page 166] by a popular podcast. Crimes involving people of color or marginalized victims such as drug users or sex workers are underrepresented in the media. The most popular stories are about murdered and missing white women, especially if they’re young, especially if they’re middle- to upper-class, especially if they’re blonde and beautiful. Think Natalee Holloway, JonBenét Ramsey, Gabby Petito. The podcast made a point of this underrepresentation, suggesting the police’s initial failure to investigate Relisha’s disappearance may have been linked to her race and her family’s precarious economic status. By the time police got involved, Relisha had missed over a month of school, and her mother hadn’t seen her in 18 days. When police did start to ask questions, the man who had taken her killed his wife, then himself. Relisha has never been found. ________ Police began searching for Jodie right away. Like most Vermonters, she was white. In all, 50 officers and a canine unit conducted a ground search in a one-mile radius around Jodie’s abandoned Jeep. There was an expanded search, an aerial search, a search of three miles of the nearby Gihon River. An unidentified woman at a hospital in Dartmouth, New Hampshire seemed to fit Jodie’s description, but she wasn’t Jodie. Soon people were comparing Jodie’s disappearance to those of two other young women in the area. On February 9, 2004, U Mass Amherst student Maura Murray vanished after an apparent car crash in rural New Hampshire. Then, just over a month later, 17-year-old Brianna Maitland disappeared after leaving her job at a restaurant in northern Vermont. The similarities—missing women, abandoned cars, geographical proximity—were compelling. People began to murmur about a serial killer. Then, on June 2, just over a week after she went missing, Jodie’s body was found. Her husband was already in custody, giving his confession. [End Page 167] ________ My writing studio at the...

Geomorphic response to historic and ongoing human impacts in a large lowland river

AbstractLowland coastal plain rivers are important for navigation and ecosystems, having unique concerns regarding water and sediment management. The Apalachicola River in Florida, the lower end of the ACF (Apalachicola–Chattahoochee–Flint) system, had historical modifications beginning in the 1800s. Most impacts are attributable to the Apalachicola Navigation Project in the latter half of the 20th century, which included dredging, disposal, rock and snag removal, artificial cutoffs, and wing‐dike building.As one of few studies using paired hydrographic surveys over a long reach and time (170 km, 50 years), we defined four zones of bed elevation change between 1960 and 2010 based on the cumulative thalweg elevation plots. The river has four bed change zones: (1) uppermost, marked degradation from river mile (RM) 106 to 85 because of dam construction; (2) middle, minimal degradation from RM 85 to 34; (3) artificial cutoff zone, highest degradation, from RM 34 to 27; and (4) lowermost zone, aggradation from RM 27 to Apalachicola Bay because of upstream bed and bank sediment disturbances. Artificial cutoffs and lithology influence lateral migration, with rates being highest in cutoff zones and least in areas with some bedrock upstream and finer sediments downstream. Length changes from 1941 to 2019 are stable, except for the middle reach, which lengthened nearly 10%, and the lower non‐tidal reach, where length shortened with cutoffs then regained in subsequent decades. Minimizing disturbance has led to 18% of the sand bar area revegetating since a decade of dredging ended. This framework helps in understanding historic and ongoing human activities, notably upstream water consumption, connectivity changes, sediment inputs, and climate change, that will affect the water and sediment management of the river, its floodplain, and bay, thus varying approaches for restoration.

Spatiotemporal hydrological analysis of streamflows and groundwater recharge for sustainable water management in Prince Edward Island, Canada

AbstractPrince Edward Island (PEI), Canada, entirely depends on groundwater for freshwater supplies, which also highly feeds streamflows. In a few watersheds, pumping has had disturbed steady‐state conditions and reduced streamflows. Spatiotemporal hydrological analysis of streamflows and recharges was performed in its scattered watersheds. Mill, Wilmot, West, Winter, and Bear River watersheds were modeled by the Soil and Water Assessment Tool (SWAT) under the shallow water‐table conditions, besides other analyses. The model was calibrated against 120 observed mean monthly flows (1995–2004) and validated for another 120 observations (2005–2014), with Nash–Sutcliffe efficiency (NSE) as the major performance assessment parameter. The model accurately simulated mean monthly flows for all watersheds during 1995–2014, except Winter River watershed (NSE = 0.02–0.33), wherein it overpredicted by 31%–52% and 5–12% in Wilmot River (NSE = 0.28–0.64). Streamflows were found highly dependent on groundwater; therefore, pumpings of 6.92 and 0.73 million cubic meters (MCM)/year caused the overpredictions in Winter and Wilmot watersheds, as SWAT cannot account pumping. In the rest three watersheds with negligible pumping, 4%–18% underprediction was due to multisite calibration. Spatially, streamflows randomly varied between 555 and 811 mm/year across watersheds, whereas thick and highly permeable sandstone produced higher recharges, the maximum ~600 mm/year in the eastern forest‐dominated Bear River watershed, lesser in western ~330 mm/year, and moderate ~450 mm/year in central watersheds. Temporally, March–May are the months of highest streamflows, whereas recharge is maximum during April–July. The succession trend justified strong surface water–groundwater interactions. Existing Water Extraction Permitting Policy ensures sustainability at the island scale. It sets pumping limit at 20% of recharge, that is, 0.48 km3/year altogether, against the present pumping of ~0.04 km3/year, yet a few watersheds are somewhat water‐stressed due to population and pumping concentration. Expansion of streamflow and groundwater monitoring, promoting population and pumping in rural areas, and more scrutiny for further pumping permits in water‐stressed watersheds are quite important for sustainable water management in PEI.

Baseline framework for assessing community resilience using a balanced index approach and spatial autocorrelation in the Mill river watershed, Nassau County, New York

Community resilience examines how communities react, adapt, and recover from adverse situations and has grown out of disaster research over the last 20 years. This paper presents a baseline framework to identify, measure, evaluate, and explain resilience across the Mill River watershed. A balanced composite index was constructed using 30 indicators aggregated into four categories (economic, social, health, and ecological resilience). The geospatial distribution of resilience scores represents a clustered, non-random pattern. Five clusters were identified based on overall resilience scores and geography. Cluster 1 (High Resilience–Headwaters) represent high economic standing and minimal ecological risks; Cluster 2 (High Resilience–Mid-watershed) represent high health and ecological resilience with stark socioeconomic disparities with neighbouring communities; High Cluster 3 (High Resilience–Coastal) represents extensive affluence with coastal vulnerabilities; Cluster 4 (Low Resilience–Coastal) represent coastal vulnerabilities and the lowest overall resilience; and, Cluster 5 (Low Resilience Mid-Watershed) represents places with a history of socioeconomic inequities with below average overall resilience. Since the Mill River Watershed is a microcosm of Long Island, New York, this research provides a data-based framework that can be implemented for measuring resilience across Long Island with recommendations for improving the framework. This research analyzes the coexisting nature of extremes in the study area: affluent vs. impoverished and inland resilience vs coastal vulnerability. It suggests that resilience can be effectively improved if communities can identify their strengths and weaknesses for which this index provides baseline data.

Realignments of the Colorado River by ∼2 m.y. of rotational bedrock landsliding: The Surprise Valley landslide complex, Grand Canyon, Arizona

Abstract The Surprise Valley landslide complex is the name used here for a group of prominent river-damming landslides in Grand Canyon (Arizona, USA) that has shifted the path of the Colorado River several times in the past 2 m.y. We document a sequence of eight landslides. Three are Toreva-block landslides containing back-rotated but only mildly disrupted bedrock stratigraphy. The largest of these landslides, Surprise Valley landslide, is hypothesized to have dammed the Colorado River, cut off a meander loop through Surprise Valley, and rerouted the river 2.5 km south to near its present course at the Granite Narrows. Another bedrock landslide, Poncho's runup, involved a mass detachment from the north side of the river that drove a kilometer-scale bedrock slab across the river and up the south canyon wall to a height of 823 m above the river. A lake behind this landslide is inferred from the presence of mainstem gravels atop the slide that represent the approximate spillway elevation. We postulate that this landslide lake facilitated the upriver 133 Mile slide detachment and Toreva block formation. The other five landslides are subsequent slides that consist of debris from the primary slides; these also partially blocked and diverted the Colorado River as well as the Deer Creek and Tapeats Creek tributaries into new bedrock gorges over the past 1 m.y. The sequence of landslides is reconstructed from inset relationships revealed by geologic mapping and restored cross-sections. Relative ages are estimated by measuring landslide base height above the modern river level in locations where landslides filled paleochannels of the Colorado River and its tributaries. We calculate an average bedrock incision rate of 138 m/m.y. as determined by a 0.674 ± 0.022 Ma detrital sanidine maximum depositional age of the paleoriver channel fill of the Piano slide, which has its base 70 m above the river level and ∼93 m above bedrock level beneath the modern river channel. This date is within error of, and significantly refines, the prior cosmogenic burial date of 0.88 ± 0.44 Ma on paleochannel cobbles. Assuming steady incision at 138 m/m.y., the age of Surprise Valley landslide is estimated to be ca. 2.1 Ma; Poncho's runup is estimated to be ca. 610 ka; and diversion of Deer Creek to form modern Deer Creek Falls is estimated to be ca. 400 ka. The age of the most recent slide, Backeddy slide, is estimated to be ca. 170 ka based on its near-river-level position. Our proposed triggering mechanism for Surprise Valley landslides involves groundwater saturation of a failure plane in the weak Bright Angel Formation resulting from large volumes of Grand Canyon north-rim groundwater recharge prior to establishment of the modern Deer, Thunder, and Tapeats springs. Poncho's and Piano landslides may have been triggered by shale saturation caused by 600–650 ka lava dams that formed 45 river miles (73 river km; river miles are measured along the Colorado River downstream from Lees Ferry, with 1 river mile = 1.62 river kms) downstream near Lava Falls. We cannot rule out effects from seismic triggering along the nearby Sinyala fault. Each of the inferred landslide dams was quickly overtopped (tens of years), filled with sediment (hundreds of years), and removed (thousands of years) by the Colorado River, as is also the potential fate of modern dams.

Shell density variation among populations of the ornate rocksnail Lithasia geniculata (Gastropoda: Pleuroceridae)

Abstract Pleurocerid snails generally exhibit shell variation with the environment and predation; shells are thicker, more conic, and harder to crush upstream than downstream. Little is known, however, about whether the density of shell material varies in a similar fashion and how it correlates with other shell characteristics and the environment. Using eight populations of Duck River Lithasia geniculata, we measured shell material density as a function of X-ray radiopacity and shell thickness and correlated it with river mile and crushing strength. Populations differed in their density, which was positively correlated with river mile whether adjusted for shell thickness or not. Regression indicated that shell density showed a positive correlation with thickness and a negative correlation with crushing strength. Our results in L. geniculata are the first to show variation in shell material density in pleurocerids, and our data suggest adaptive trade-offs in response to hydrology and predation pressures.

Impacts of an extreme flood on the ecosystem of a headwater stream

Headwater streams are the smallest parts of rivers but make up the majority of river miles. The chemistry and macroinvertebrate composition of such streams are among the most important indicators of their environmental health. Macroinvertebrates are affected namely by runoff genesis and, in many regions of the world, also by acid atmospheric deposition and its consequences. The aim of this paper is to evaluate the impacts of an extreme summer flash flood on the physical environment, chemistry and macroinvertebrates in a small headwater stream located in the Beech-woods National Nature Reserve of the Jizera Mts. (Northern Bohemia, Czech Republic). The studied stream is characterized by a pluvial hydrologic regime with perennial streamflow uniformly distributed within the year, with peak-flows originating mainly from summer rainstorms, and moderate current anthropogenic acidification. During the observed summer flash flood of the return period near 1,000 years, high currents (1-2.5 m s-1) flushed out 2.7 m3 of sand and gravel from the streambed, resulting in a devastating effect on macroinvertebrates. Both number of species/taxa and diversity were reduced by about 50% while the abundance of surviving taxa was reduced to about 10% compared with before the flood. The following spring after the event, both number of species/taxa, diversity and abundance increased, partially due to the temporary unsuccessful colonization of the site by several alien species creating a peak of biological diversity, but complete recovery of the original macroinvertebrate assemblages was not observed even during the subsequent two years. On the other hand, a significant drop in sulphate contents and rising alkalinity observed in stream waters during base flow conditions after the flood indicate positive effects on recovery of the aquatic environment by depleting the catchment sulphur pool. Thus, the flood did not significantly alter the long-term recovery of the studied headwater stream from acidification.

Sources of 2,3,7,8-Tetrachlorodibenzo-p-dioxin and Other Dioxins in Lower Passaic River, New Jersey, Sediments.

Elevated levels of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and other contaminants have been reported in lower Passaic River, New Jersey, USA, sediments since the 1980s. Nearly 8000 surficial and buried sediment samples have been collected along the 17 miles (27.4 km) of river and analyzed for various contaminants, including the seventeen 2,3,7,8-substituted PCDD/F congeners. Principal component analysis and hierarchical cluster analysis reveal spatial heterogeneity in the distribution of dioxin congeners, with respect to both sediment depth and river mile. Polytopic vector analysis resolved 11 unique 2,3,7,8-substituted dioxin congener profiles in the river sediment. The profiles were consistent with multiple dioxin source types, including manufacture of certain dyes and pigments, chlorinated industrial chemicals, hexachlorophene, polychlorinated biphenyls, waste disposal and incineration, the production and use of 2,4,5-trichorophenol (2,4,5-TCP), and other industrial processes. The distribution of dioxin profiles in surface and buried river sediments is indicative of multiple inputs of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) and other dioxins at different locations along the lower Passaic River. These findings are inconsistent with historical claims that a former herbicide manufacturing plant in the lower reach of the river is the only significant 2,3,7,8-TCDD source and consistent with evidence of several different inputs associated with the production, use, and/or disposal of 2,4,5-TCP at several locations along the lower Passaic River. Environ Toxicol Chem 2021;40:1499-1519. © 2020 SETAC.

Temporal Influences on Selenium Partitioning, Trophic Transfer, and Exposure in a Major U.S. River

Hydrologic and irrigation regimes mediate the timing of selenium (Se) mobilization to rivers, but the extent to which patterns in Se uptake and trophic transfer through recipient food webs reflect the temporal variation in Se delivery is unknown. We investigated Se mobilization, partitioning, and trophic transfer along approximately 60 river miles of the selenium-impaired segment of the Lower Gunnison River (Colorado, USA) during six sampling trips between June 2015 and October 2016. We found temporal patterns in Se partitioning and trophic transfer to be independent of those in dissolved Se concentrations and that the recipient food web sustained elevated Se concentrations from earlier periods of high Se mobilization. Using an ecosystem-scale Se accumulation model tailored to the Lower Gunnison River, we predicted that the endangered Razorback Sucker (Xyrauchen texanus) and Colorado Pikeminnow (Ptychocheilus lucius) achieve whole-body Se concentrations exceeding aquatic life protection criteria during periods of high runoff and irrigation activity (April-August) that coincide with susceptible phases of reproduction and early-life development. The results of this study challenge assumptions about Se trophodynamics in fast-flowing waters and introduce important considerations for the management of Se risks for biota in river ecosystems.

Picking Up Where the TMDL Leaves Off: Using the Partnership Wild and Scenic River Framework for Collaborative River Restoration

The National Wild and Scenic Rivers Act protects less than ¼ of a percent of the United States’ river miles, focusing on free-flowing rivers of good water quality with outstandingly remarkable values for recreation, scenery, and other unique river attributes. It predates the enactment of the Clean Water Act, yet includes a clear anti-degradation principle, that pollution should be reduced and eliminated on designated rivers, in cooperation with the federal Environmental Protection Agency and state pollution control agencies. However, the federal Clean Water Act lacks a clear management framework for implementing restoration activities to reduce non-point source pollution, of which bacterial contamination impacts nearly 40% of the Wild and Scenic Rivers. A case study of the Musconetcong River, in rural mountainous New Jersey, indicates that the Wild and Scenic Rivers Act can be utilized to mobilize and align non-governmental, governmental, philanthropic, and private land-owner resources for restoring river water quality. For example, coordinated restoration efforts on one tributary reduced bacterial contamination by 95%, surpassing the TMDL goal of a 93% reduction. Stakeholder interviews and focus groups indicated widespread knowledge and motivation to improve water quality, but resource constraints limited the scale and scope of restoration efforts. The authors postulate that the Partnership framework, enabled in the Wild and Scenic Rivers Act, facilitated neo-endogenous rural development through improving water quality for recreational usage, whereby bottom-up restoration activities were catalyzed via federal designation and resource provision. However, further efforts to address water quality via voluntary participatory frameworks were ultimately limited by the public sector’s inadequate funding and inaction with regard to water and wildlife resources in the public trust.

Assessment of the effective width of riparian buffer strips to reduce suspended sediment in an agricultural landscape using ANFIS and SWAT models

Riparian buffers are important features that help to mitigate suspended sediment loads within rivers running through agricultural landscapes. Evaluating their effectiveness for sediment control by different modelling approaches can help direct beneficial management practices. The Soil and Water Assessment Tool (SWAT) model and the Adapted Neuro-Fuzzy Inference System (ANFIS) based model were used for prediction of suspended sediment concentrations (SSC) and sediment loads in the Mill River watershed (PEI, Canada). Those models were then used to assess the impact of riparian buffer widths in reducing sediment loads. The ANFIS model predicted measured SSC more accurately than the SWAT model. The relationship between buffer width and sediment reduction was asymptotic, and the relationship begins to plateau when the width reaches 50 m. Increasing the buffer width from 15 to 100 m led to an increase in sediment loads retention of 30.5% and 36.2% of the total stream sediment load for the SWAT and ANFIS models, respectively. This study highlighted that a data-driven ANFIS based model can be used to simulate the impact of land use changes on the sediment delivery in a river.

Supporting Coastal Resiliency by Investigating Tidal Reach and Inter-Connected Factors in Coastal Georgia

Increasing our understanding of the tidal dynamics, the extent of tidal reach, and storm surge impacts on near-coastal areas of Georgia and South Carolina rivers is a significant research opportunity. It has the potential to yield benefits to sustainable planning, ecosystem protection, and risk management for regulators and state agencies, local municipalities, coastal residents, and other regional stakeholders. This study leveraged existing United States Geological Survey (USGS) water level data for the Savannah River, added additional water level gauges in key areas for less than one year, and analyzed these combined large data sets with modified wavelet analysis and Fourier analysis. One significant outcome of the research included confirmation of river mile 45, historically referred to as Ebenezer Landing, as the head of tide. We also provide information on the dynamics of wave propagation through the near-coastal area of the Savannah River, give indication of critical areas of concern for flooding resulting from interactions between the interconnected factors affecting elevated upstream flows and storm tides, and discuss relevance of study results for various stakeholders.

Measuring benefits from spatially-explicit surface water quality improvements: The roles of distance, scope, scale, and size

Programs to improve water quality do not improve all water bodies equally. Evaluation of the benefits of such programs must account for where improvements occur and the relative magnitude of improvements that occur in different places. This study uses a choice experiment survey to explore how the value to a household of a surface water quality improvement varies as a function of (i) the distance between the household and the affected streams and rivers, (ii) the degree to which the quality of the water has been improved, (iii) how many stream and river miles have been improved, and (iv) the sizes of the affected streams and rivers. Results show evidence that value declines with distance in an approximately linear way, weak evidence that large rivers are worth more than small rivers, and no evidence that willingness-to-pay is nonlinear in either the degree of water quality improvement or the number of stream miles improved. These results indicate that it may be defensible in applied work to value small, spatially-explicit water quality improvement projects independently and then sum over projects.

Devil’s Den to Lickingwater: The Mill River through Landscape and History. By John Sinton. Amherst: Levellers Press, 2018. xvi + 299 pp. Illustrations, maps, graph, chart, appendix, notes, and index. Paper $28.25.

<i>Devil’s Den to Lickingwater: The Mill River through Landscape and History</i>. By John Sinton. Amherst: Levellers Press, 2018. xvi + 299 pp. Illustrations, maps, graph, chart, appendix, notes, and index. Paper $28.25.

The proposed change to the definition of “waters of the United States” flouts sound science

The U.S. Environmental Protection Agency (EPA) and Army Corps of Engineers (hereafter, “the agencies”) have issued a proposed rule (1) that would remove Clean Water Act (CWA) protections from more than half of wetlands and one-fifth of streams in the United States (2). This move sharply contrasts with reports indicating that US waters remain threatened by storms, droughts, contaminants, algal blooms, and other stressors. Even the EPA’s National Water Quality Inventory detected poor conditions in 46% of stream and river miles and 32% of wetlands (3). In short, the proposed rule does not reflect the best-available science and, if enacted, will damage our nation’s water resources. A proposed rule under consideration by the US federal government does not reflect the best-available science and, if enacted, will damage the nation’s water resources. Image credit: Shutterstock/Martha Marks. Despite the CWA’s mandate “to restore and maintain the chemical, physical, and biological integrity of the Nation’s waters” (4), controversy persists over jurisdiction. For decades, the protected “waters of the United States” (WOTUS) included traditionally navigable waters (TNWs), such as large rivers, lakes, and territorial seas, as well as waters meaningfully connected to or affecting the integrity of TNWs. Operationalizing this connection has become a flashpoint for the science and politics of water protection. Connectivity among waterbodies was the cornerstone of the Obama administration’s Clean Water Rule (CWR), which reflected a state-of-the-science synthesis of more than 1,200 scientific publications [known as the “Connectivity Report” (5)], input from 49 experts, and a rigorous review by a 25-member panel of the EPA’s Scientific Advisory Board (SAB) (6). Since then, scientific evidence supporting the 2015 CWR, and hence contradicting the new proposal, has only accumulated, especially as related intermittent (i.e., flow seasonally) and ephemeral (i.e., flow periodically, after precipitation events) streams, riparian and floodplain zones, and non-floodplain wetlands … [↵][1]1To whom correspondence may be addressed. Email: sullivan.191{at}osu.edu. [1]: #xref-corresp-1-1

Historical record of an alligator gar,Atractosteus spatula(Lacépède, 1803), captured on the floodplain of the Middle Mississippi River at Columbia, Illinois, USA

Historical photographs, newspapers, and interviews can provide useful information on the abundance, distribution, and habitat use of rare fish species and can be useful in the development of conservation and management plans for target species. We report on the historical occurrence of Atractosteus spatula (alligator gar) on the Middle Mississippi River (MMR) floodplain near Columbia, Illinois (Monroe County), approximately 280.5 river kilometers above the Ohio River (River Mile 168) during the spring of 1937. Based on measurements taken from a photograph of a captured specimen and Mr. Paul Lopinot's recollection of the specimen's weight, the alligator gar was approximately 2.0 m total length and weighed 60 kg. An additional 25–30 large alligator gar were observed on the floodplain approximately 3.6 km from the river. The loss of seasonally inundated floodplain habitat due to construction of an extensive agricultural levee system on the MMR may be a contributing factor to the decline of the alligator gar in the northern portion of its range.

Baseline Qualitative and Quantitative Mussel Surveys of the Mill River System, Massachusetts, Prior to Final Dam Removal

Baseline Qualitative and Quantitative Mussel Surveys of the Mill River System, Massachusetts, Prior to Final Dam Removal

Comparison of different spatial interpolation methods for historical hydrographic data of the lowermost Mississippi River

ABSTRACTThe lowermost Mississippi River (LMR) is important to the environment and economy of continental United States. Although bathymetric data have been collected over many decades at numerous cross-sectional sounding points, there has been no consensus on appropriate interpolator for generating bathymetry. Such interpolation is critical to reliable assessments of channel morphology and channel change, which serve for dredging, engineering projects, and mapping of navigation hazards. This study aimed to identify an optimal spatial interpolation for mapping the river bathymetry from cross-sectional sounding measurements. We evaluated a variety of spatial interpolation methods including Inverse Distance Weighting (IDW), Ordinary Kriging (OK), Radial Basis Function (RBF), and Local Polynomial Interpolation (LPI). In addition, we also considered the anisotropic form of IDW (Elliptical IDW as EIDW), that of OK (OKA), and Universal Kriging (UK). Two reaches in the LMR, located between approximately RM (River Miles) 170–140 and RM 60–35, were chosen as the study area. Those interpolators were compared in terms of root-mean-square error (RMSE), mean absolute error (MAE), bias, and coefficient of determination (r2). Our results demonstrate that both of RBF and OKA performed the best in mapping the bathymetry of study reaches. Furthermore, our results also indicate that the addition of anisotropy can significantly reduce RMSE by 5–20%, as compared to isotropic methods. The findings better inform other researchers on selecting a proper interpolation technique for mapping river bathymetry, particularly for other reaches of the Mississippi River.

Detecting river-scale turbidity disturbance after rainfall using NEXt-Generation Weather RADar (NEXRAD) and the Intelligent River

Turbidity of surface water is a major environmental and human health issue in the United States. This study integrated two years (January 1, 2015, to December 31, 2016) of high frequency in situ turbidity and stream flow data with daily Next Generation Radar rainfall data for nine Intelligent River sensors in order to learn about river-scale turbidity dynamics and disturbances after rainfall in the Savannah River, Georgia. Analysis of Intelligent River turbidity data revealed a highly dynamic system. A prevailing spatial pattern of increasing turbidity with decreasing distance from the Atlantic Ocean was evident at any given time during the study period, but the typical distribution of turbidity can be disrupted for days to months. Observed turbidity disturbances are related to periods of increased stream flow and rainfall events. Short-term (one to seven days) turbidity disturbances at river miles 150 or greater appear to be intricately linked to rainfall, but turbidity disturbances after the same rainfall events at river miles 27 and 61 were much less dramatic or not detected at all. These results paint an expectedly complex picture of high-frequency turbidity measurements at nine locations in a large river network. However, these results also highlight the feasibility and novelty of integrating NEXt-Generation Weather RADar (NEXRAD) and in situ sensing for data-driven knowledge discovery in soil and water conservation.