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Stream Outputs (stream + output)
Selected AbstractsSources of stream sulphate in headwater catchments in Otter Creek Wilderness, West Virginia, USAHYDROLOGICAL PROCESSES, Issue 4 2001Ross D. Fitzhugh Abstract Upland forested catchments in the Appalachian Plateau region receive among the greatest rates of atmospheric sulphur (S) deposition in the eastern USA, although coal mines and S-bearing minerals in bedrock may also contribute to stream acidity in this region. Watershed mass balance and stable S isotopic values (,34S) of sulphate (SO42,) were used to assess the contributions to stream SO42, from atmospheric and lithogenic sources at Yellow Creek (YC), a headwater catchment on the Appalachian Plateau in West Virginia. Oxygen isotopic values (,18O) of water were used to study catchment hydrology. Stream output of SO42, was c. 60% of atmospheric S deposition during a relatively dry year, whereas atmospheric S input was nearly balanced by stream output during a year with above normal amounts of precipitation. The temporal patterns and values of ,34S were similar between bulk precipitation and stream water at two upper elevation sites. At the lowest elevation site, stream ,34S values were similar to bulk precipitation values during the dormant season but were slightly lower than precipitation during the low-flow summer, probably as the result of a greater proportion of stream water being derived from deep hydrological flowpaths that have contacted S-bearing minerals with low ,34S values in coal seams. Stream ,34S values at YC were significantly higher than at Coal Run, a catchment containing abandoned coal prospects and having a greater amount of S-bearing minerals than YC. Results suggested that lithogenic S is a relatively minor source and that atmospheric deposition is the principal source of stream SO42,, and thus stream acidity, at YC. Copyright © 2001 John Wiley & Sons, Ltd. [source] Transit time distributions of a conceptual model: their characteristics and sensitivitiesHYDROLOGICAL PROCESSES, Issue 12 2010S. M. Dunn Abstract The internal behaviour of a conceptual hydrological and tracer transport model, STREAM, has been examined through generation of transit time distributions for the model. The model has been applied to a small sub-catchment of the Lunan Water in the east of Scotland where daily precipitation and stream water samples have been analysed for isotope content. Transit time distributions are generated by numerically tracking pulse inputs of tracer to the model and evaluating the simulated stream outputs. A set of baseline simulations was first established through calibration to time series of stream flow. A series of model experiments was then undertaken to assess the sensitivity of the simulated transit time distributions to different model parameterizations, flow paths and mixing assumptions. The results of the analysis show that the model transit time distributions do not conform to any simple statistical function and that their characteristics can be significantly altered depending on how the model is set up. The analysis provided valuable insight into the functioning of the model and could be usefully applied to other model codes. Comparison of the transit time distributions generated by conceptual models with data-based empirical evidence of distributions gives the potential to close the gap in understanding the physical explanation for why catchment systems behave as they do. Copyright © 2010 John Wiley & Sons, Ltd. [source] FOG AND ACIDIFICATION IMPACTS ON ION BUDGETS OF BASINS IN NOVA SCOTIA, CANADA,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 3 2000Shelagh Yanni ABSTRACT: We examined hydrogeochemical records for a dozen watersheds in and near Kejimkujik National Park in southwestern Nova Scotia by relating stream ion concentrations and fluxes to atmospheric deposition, stream type (lake inlet versus outlet; brown versus clear water), and watershed type (catchment area, topography, soils, and dominant forest cover type). We found that fog and dry deposition make important contributions to S, N, Cl, H, Ca, Mg, K, and Na inputs into these watersheds. Seasalt chloride deposition from rain, snow, fog, and dry deposition equal total stream outputs on a region-wide basis. Chloride outputs, however, differ among watersheds by a factor of about two, likely due to local differences in air flow and vegetational fog interception. We found that most of the incoming N is absorbed by the vegetation, as stream water NO3 - and NH4+ are very low. Our results also show that the vegetation and the soils absorb about half of the incoming SO42. In comparison with other North American watersheds with similar forest vegetation, Ca outputs are low, while Mg and K outputs are similar to other regions. Soil exchangeable Ca and soil cation exchange capacity are also very low. We found that first-order forest streams with no upstream lakes have a distinct seasonal pattern that neither corresponds with the seasonal pattern of atmospheric deposition, nor with the seasonal pattern of downstream lake outlets. [source] | ||||||||||