Channel delineation datasets associated with "River channel response to invasive plant treatment across the American Southwest"

The dataset contains river channel delineations in the form of an ArcGIS PRO shapefile. The shapefile contains polygons that were generated for each study site. There are fifteen study sites. Each study site contains a treated and untreated reach, and each of these reaches has pre- and post-treatment delineations. One study site, Chinle Creek, contains four treated reaches and four untreated reaches.Invasive riparian plants were introduced to the American Southwest in the early 19th century and contributed to regional trends of decreasing river channel width and migration rate in the 20th century. More recently efforts to remove invasive riparian vegetation (IRV) have been widespread, especially since 1990. To what extent has IRV treatment reversed the earlier trend of channel narrowing and reduced dynamism? In this study, paired treated and untreated reaches at 15 sites along 13 rivers were compared before and after IRV treatment using repeat aerial imagery to assess long-term (~10 year) channel change due to treatment on a regional scale across the Southwest U.S. We found that IRV treatment significantly increased channel width and floodplain destruction. Treated reaches had higher floodplain destruction than untreated reaches at 14 of 15 sites, and IRV treatment increased the rate of floodplain destruction by a median factor of 1.9. The effect of treatment increased with the stream power of the largest flow over the study period. Resolving observations of channel change into separate measures of floodplain destruction and formation provided more information on underlying processes than simple measurements of channel width and centerline migration rate. Restoration practitioners who perform IRV treatment projects often focus on wildlife or vegetation response; however, geomorphic processes should be considered in restoration planning because they drive aquatic habitat and vegetation dynamics, and because of the potential for damage to downstream infrastructure. Depending on the restoration goal, management practices can be used to enhance or minimize the increase in channel dynamism caused by IRV removal

Field-based Learning in Surface and Groundwater Processes: Preparing Water Literate Citizens and Water Resource Professionals

Hydrologic field stations installed in the Cache La Poudre River basin will provide authentic field-based learning opportunities for non-majors and majors at Colorado State University to prepare a water literate citizenry and water resource professionals. Previous experience from a campus well field has demonstrated the effectiveness of local field-based instruction in water resources. Results from three semesters of perception surveys and pre- and post-knowledge tests show increased student satisfaction and knowledge gain in fundamental water concepts through the groundwater field exercise. The new hydrologic stations are designed to build upon these results to further improve undergraduate teaching and learning of water concepts in Warner College of Natural Resources (WCNR) using the Poudre watershed as the focus. Given the numerous relevant scientific and societal issues related to our hometown watershed, now is the time to develop high-impact watershed-based learning tools for undergraduates. The hydrologic field stations will span a gradient along the Poudre River and its tributaries from the mountains at CSU’s Pingree Park campus to the plains, providing a full spectrum of geologic, climatic, biologic, and land use characteristics in the watershed. The mid-canyon site at Gateway Natural Area will be the first location accessed either in the field, virtually, or both, by 1300 students in twelve courses in WCNR. Students will collect and analyze the water quantity and quality data that are relevant to the future use of the Cache La Poudre River watershed, and all student-collected data will be made available on the FLOW (Fostering Learning of Water) website. Key learning goals include mastering surface and groundwater flow measurement, flow calculation and interpretation, hydrologic and geomorphic mapping and spatial analysis, assessing physical-biotic interactions along riparian corridors, evaluating human impacts to river networks, assessing alluvial aquifer properties, and computer modeling, thus giving students the broad knowledge and scientific skills necessary to participate as water literate citizens, enter the environmental science workforce, or pursue graduate research

Working with wood in rivers in the Western United States

Recognition of the important physical and ecological roles played by large wood in channels and on floodplains has grown substantially during recent decades. Although large wood continues to be routinely removed from many river corridors worldwide, the practice of wood reintroduction has spread across the United States, the United Kingdom and western Europe, Australia, and New Zealand. The state-of-science regarding working with wood in rivers was discussed during a workshop held in Colorado, USA, in September 2022 with 40 participants who are scientists and practitioners from across the USA, UK, Europe, and Japan. The objectives of this paper are to present the findings from the workshop; summarize two case studies of wood in river restoration in the western United States; and provide suggestions for advancing the practice of wood in river management. We summarize the workshop results based on participant judgements and recommendations with respect to: (i) limitations and key barriers to using wood, which reflect perceptions and practicalities; (ii) gaps in the use of large wood in river management; (iii) scenarios in which wood is generally used effectively; and (iv) scenarios in which wood is generally not used effectively. The case studies illustrate the importance of the local geomorphic context, the configuration complexity of the wood, and the potential for modification of river corridor morphology to enhance desired benefits. Moving forward, we stress the importance of collaboration across disciplines and across communities of research scientists, practitioners, regulators, and potential stakeholders; accounting for stakeholder perceptions of the use of large wood; and increasing non-scientist access to the latest state-of-science knowledge

Pleistocene glacial outburst flooding along the Big Lost River, east-central Idaho

Cataclysmic flood features including scabland topography, streamlined hills, a loess scarp, and flood transported boulders were mapped along Box Canyon, lower Big Lost River, eastern Snake River Plain. These features are similar to landforms within the Cheney-Palouse scabland tract, eastern Washington, formed by the great Missoula floods. Step-backwater hydraulic modeling of flow through the 11 km-long Box Canyon gorge indicates that a discharge of 60,000 m^3sec^-1 was required to produce the geologic paleostage evidence. Maximum stream power per unit area of bed locally attained values of 26,000 Wm^-2, which is comparable to the more extensive late Pleistocene Bonneville and Missoula flows. Flood power, estimated to exceed 1000 Wm^-2 , induced plucking of the jointed-basalt channel banks of Box Canyon. Tracts of scabland with networks of anastomosing channels migrated headward, driven by unit stream power values in the 600-1000 Win^-2 range. Deposition of the largest flood boulders occurred above a limiting unit stream power of 1400 Wm^-2. This ceiling on boulder deposition indicates that entrainment of these largest boulders probably took place under maximum unit stream power conditions (26,000 Wm^-2). The irregular volcanic rift topography along Box Canyon was the dominant control on removal and accumulation of flood boulders, however. Paleoflooding along Box Canyon may in part, although probably not solely, be attributed to outbursts from a glacial lake in the headwaters region located in the Pioneer Mountains.hydrology collectio

Modeling pool sediment dynamics in a mountain river

2001 Fall.Includes bibliographical references.An increasingly important source of sediment into river systems is sediment that accumulates within reservoirs and is subsequently released into the downstream ecosystem. In Colorado alone, five large-scale sediment releases from reservoirs within the last decade have resulted in a host of environmental hazards, particularly the loss of aquatic biota and their habitat. The most recent example occurred in September 1996 when approximately 7,000 m3 of clay- to gravel-sized sediment were released from Halligan Dam into the North Fork Cache la Poudre River in northern Colorado. The sediment caused extensive aggradation of the original cobble-boulder bed, primarily in pools, and complete fish mortality for 12 km downstream from the dam. Because of the thriving, pre-release wild trout fishery downstream from Halligan Reservoir, flushing of sediment from pools to recreate overwinter fish habitat was of prime concern. The purpose of this investigation was to evaluate the applicability of various hydraulic and sediment transport models as predictors of pool recovery along the steep gradient, bedrock-controlled North Fork River. Two modeling scenarios representing a low and high flushing discharge were modeled using one- and semi-two dimensional sediment transport models, HEC-6 and GSTARS2.0, respectively. The models were calibrated against quantitative measurements of pool bed elevation obtained during field surveys. HEC-6 results indicate that long-term, robust simulations yield the closest agreement between predicted and measured pool bed elevation change. Greater than 50 percent of the actual scour and deposition within three pools was modeled using HEC-6.Modeling accuracy using GSTARS2.0 was considerably more variable, and no pool-wide trends were obtained. A two-dimensional, finite element hydraulic model, RMA2, improved delineation of flow hydraulics in areas of flow separation and recirculation within a compound pool.RMA2 results of depth-averaged velocity magnitude and vectors broadly agree with timed photographs of surface flow patterns, and correspond with velocity measurements for low-velocity areas such as eddy pools. Patterns of boundary shear stress and a particle stability index accurately predict gross areas of scour and deposition, but fail to represent the simultaneous aggradation and degradation measured in pools. Estimates of bedload transport capacity from the two-dimensional modeling results are one order of magnitude greater than measured transport rates, and indicate that supply-limited conditions existed along the North Fork following a clear-water flushing release. Further correlations between observed and modeled sedimentation patterns are hindered by the disparity in resolution between the field data and modeled results; field-based cross sectional information is quickly outstripped by the finite element model RMA2. Finally, a conceptual model of pool sediment dynamics was developed for water resource specialists as an alternative to the time-intensive effort and expertise required of the numerical modeling. Predictable sites of channel aggradation and degradation resulting from a sediment pulse are identified on a reach-scale hierarchy. Processes of sediment delivery, storage, and transfer into and out of eddies that influence fish occur on the width scale, however. Sedimentation within laterally confined pools is dependent on pool geometry, distance downstream from the dam (a surrogate of sediment supply), and the duration and magnitude of flows following the release. At low flows, sediment deposition is restricted to small areas of recirculating flow. As discharge increases, migration of the separation point and development of a strong shear zone limits the transfer of sediment between the eddy and the main flow. The sediment release from Halligan induced persistent, long-term storage of fine sediment because of an elevated channel bed and loss of channel capacity. Recognition of the hazards associated with a large influx of sediment into a riverine ecosystem is critical for a greater understanding of the effects of sediment releases, and future management of sediment within reservoirs

Accept and support a multi-thread career path to keep women in the academic stream

We propose a call to action from those of us who have navigated the academic channel to help keep women afloat through the process of seeking, securing, and ascending the ranks of faculty positions

Glacier melt runoff controls bedload transport in Alpine catchments

Research on factors affecting sediment regime in glacierized catchments under warming climates is still scarce despite its societal relevance. In particular, coarse bedload transport has never been quantitatively related to water runoff origin (snowmelt vs glacier melt), which provides important information on the role of different sediment sources (glaciers vs hillslopes and channel bed). Drawing on data from multiple spatial and temporal scales in a paradigmatic Alpine glacierized catchment, we show that glacier melt flows play a key role in coarse sediment transport dynamics. Bedload concentration measured during glacier melt flows is up to 6 orders of magnitude larger than during snowmelt. At the catchment scale and within the channel, however, minimal aggradation and degradation was detected over almost a decade. In addition, sedimentation rates at a hydropower weir, inferred from flushing frequency during the last four decades, are tightly associated to summer air temperature and not to precipitation trends, and most of sediment export occurred in July-August. However, sediment flushing frequency has been decreasing since the late 1990s despite very warm summers in the following decades. Collectively, these findings indicate that sediment is dominantly sourced from within glacier covered areas and that transport rates are thus dictated by seasonal and multi-annual glacial dynamics. As glacier melt flows decrease due to ice mass loss, our results suggest that, for similar basins, a progressive shift from supply-limited (driven by glacier activity) to transport limited (during rainfall-induced events) sediment transport will occur, disrupting the current near-equilibrium channel conditions

Meltwater-driven sediment transport dynamics in two contrasting alpine proglacial streams

Subglacial sediments are a large component of the sediment budget of glacierized catchments but insights into the subglacial origin of sediments (bedload, in particular) linked to proglacial runoff dynamics remain scarce. In this study, we use a tracer-based approach to quantify meltwater proportions related to sediment transport at two proglacial streams, draining glaciers (named debris-covered and clean glacier) of different size, aspect and elevation range with contrasting distribution and thickness of debris cover and lithology of the subglacial sediments (i.e., metamorphic vs. sedimentary), in the Sulden/Solda catchment (Italian Alps). Results indicate that the glacier melt component (75 to 80 %) was associated with bedload concentrations of 1 to 10 kg m−3 at the debris-covered glacier and much lower concentrations of 0.01 to 1 kg m−3 at the clean ice glacier. At the seasonal scale, bedload and suspended sediment concentrations at both sites strongly varied with discharge. While daily bedload concentrations varied by up to two orders of magnitude obscured the seasonal development of bedload concentrations at both sites, a clear seasonality for suspended sediment concentrations was found. At the daily scale, the relationship of discharge, bedload, and suspended sediment was more complex because discharge and sediment transport did not always follow the daily variation of air temperature, or similar daily air temperatures resulted in different discharge and sediment transport responses and vice versa. Glacier size, presence of debris cover, and substrate were identified as the main drivers of meltwater dynamics and sediment transport at both glaciers. This study adds further insights into the interplay of meltwater contributions and sediment transport, which are essential to better assess the impact of climate warming on sediment supply in glacierized catchments