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Abstract (from http://www.bioone.org/doi/abs/10.2112/JCOASTRES-D-13-00202.1): Traditional long-term (decadal) and large-scale (hundreds of kilometers) shoreline change modeling techniques, known as single transect, or ST, often overfit the data because they calculate shoreline statistics at closely spaced intervals along the shore. To reduce overfitting, recent work has used spatial basis functions such as polynomials, B splines, and principal components. Here, we explore an alternative to such basis functions by using regularization to reduce the dimension of the ST model space. In our regularized-ST method, traditional ST is an end member of a continuous spectrum of models. We use an evidence information criterion...
Abstract (from ScienceDirect): The U.S. Geological Survey (USGS) has developed the PRObability of Streamflow PERmanence (PROSPER) model, a GIS raster-based empirical model that provides streamflow permanence probabilities (probabilistic predictions) of a stream channel having year-round flow for any unregulated and minimally-impaired stream channel in the Pacific Northwest region, U.S. The model provides annual predictions for 2004–2016 at a 30-m spatial resolution based on monthly or annually updated values of climatic conditions and static physiographic variables associated with the upstream basin. Predictions correspond to any pixel on the channel network consistent with the medium resolution National Hydrography...
Summary Analysis of historical streamflow trends and their relationship to landscape characteristics is essential for understanding geographic differences in runoff within the Great Lakes basin and for distinguishing temporal trends from temporal variance. Factor analysis of streamflow records (1956–1988) from 32 US Geological Survey gauging stations within the Great Lakes basin revealed distinct spatio-temporal patterns of stream runoff within five different regions of the basin. Streams represented by the first annual factor occurred in southern Wisconsin and the lower peninsula of Michigan, and exhibited a linear increase in mean annual streamflow over the 33 year period caused by increased autumn and winter...
Agricultural nitrogen is a major contributor to Gulf of Mexico hypoxia, and research has shown that agricultural subsurface tile drainage is a major carrier of nitrogen from croplands to streams and rivers. This study compares the results of abating nitrogen under a retired-land minimization policy with those of a net revenue- maximizing policy, paying particular attention to the role of tile-drained land. Endings reveal the retirement-minimizing policy resulted in more tile-drained land being retired and less being fertilizer-managed than was optimal under the net-return maximizing policy. Also, it led to a greater economic burden being shouldered by tile- drained land. Under both cases, tile drainage dominated...
The use of conservation practices by agriculture in the United States will enhance soil organic carbon and potentially increase carbon sequestration. This, in turn, will decrease the net emission of carbon dioxide. A number of studies exist that calibrate the contribution of various individual, site-specific conservation practices on changes in soil organic carbon. There is a general absence, however, of a comprehensive effort to measure objectively the contribution of these practices including conservation tillage, the Conservation Reserve Program, and conservation buffer strips to an change in soil organic carbon. This paper fills that void. After recounting the evolution of the use of the various conservation...
Increased atmospheric CO sub(2) concentration and climate change may significantly impact the hydrological and meteorological processes of a watershed system. Quantifying and understanding hydrological responses to elevated ambient CO sub(2) and climate change is, therefore, critical for formulating adaptive strategies for an appropriate management of water resources. In this study, the Soil and Water Assessment Tool (SWAT) model was applied to assess the effects of increased CO sub(2) concentration and climate change in the Upper Mississippi River Basin (UMRB). The standard SWAT model was modified to represent more mechanistic vegetation type specific responses of stomatal conductance reduction and leaf area increase...