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Alan Kasprak

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In river valleys, fluvial and upland landscapes are intrinsically linked through sediment exchange between the active channel, near-channel fluvial deposits, and higher elevation upland deposits. During floods, sediment is transferred from channels to low-elevation nearchannel deposits [Schmidt and Rubin, 1995]. Particularly in dryland river valleys, subsequent aeolian reworking of these flood deposits redistributes sediment to higher elevation upland sites, thus maintaining naturallyoccurring aeolian landscapes [Draut, 2012].
Categories: Publication; Types: Citation
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In the Colorado River downstream of Glen Canyon Dam in the Grand Canyon, USA, controlled floods are used to resupply sediment to, and rebuild, river sandbars that have eroded severely over the past five decades owing to dam-induced changes in river flow and sediment supply. In this study, we examine whether controlled floods, can in turn resupply aeolian sediment to some of the large source-bordering aeolian dunefields (SBDs) along the margins of the river. Using a legacy of high-resolution lidar remote-sensing and meteorological data, we characterize the response of four SBDs (a subset of 117 SBDs and other aeolian-sand-dominated areas in the canyon) during four sediment-laden controlled floods of the Colorado...
Categories: Publication; Types: Citation; Tags: Aeolian Research
The data contained in these tables detail the areal extent of exposed sand, in square meters, along the Colorado River between Glen Canyon Dam, Arizona, and Bright Angel Creek, Arizona, within Glen Canyon National Recreation Area and Grand Canyon National Park. Sand exposure areas are provided as a function of Colorado River discharge, as measured at Lees Ferry, Arizona, in increments of 1000 cubic feet per second. Exposed sand extents are subdivided into mapped and unmapped sand areas; at Colorado River discharge; at flows below 8,000 cubic feet per second, the total extent of exposed sand can be estimated as the sum of field-mapped sand and that sand which was unmapped, but estimated to be present across the study...
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In river valleys, sediment moves between active river channels, near-channel deposits including bars and floodplains, and upland environments such as terraces and aeolian dunefields. Sediment availability is a prerequisite for the sustained transfer of material between these areas, and for the eco-geomorphic functioning of river networks in general. However, the difficulty of monitoring sediment availability and movement at the reach or corridor scale has hindered our ability to quantify and forecast the response of sediment transfer to hydrologic or land cover alterations. Here we leverage spatiotemporally extensive datasets quantifying sediment areal coverage along a 28 km reach of the Colorado River in Grand...
Our ability to sustainably manage the Colorado River is clearly in doubt. The Bureau of Reclamation’s 2012 Water Supply and Demand Study demonstrated the precarious balance that currently exists between water supply and the amount consumptively used by society. A future with either declining water supplies or additional consumptive uses will undoubtedly upset this balance. This balance is threatened, because: • Climate change science predicts that watershed runoff will decline due to increased evapotranspiration from rising temperatures; and • Water users, especially in the Upper Basin, aspire to increase consumptive uses by developing new projects. This white paper describes how declining runoff and increased consumptive...
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