In fall (November 2005) and winter (February 2006), we collected current-year foliage of native red spruce (Picea rubens Sarg.) growing in a reference watershed and in a watershed treated in 1999 with wollastonite (CaSiO(3), a slow-release calcium source) to simulate preindustrial soil calcium concentrations (Ca-addition watershed) at the Hubbard Brook Experimental Forest (Thornton, NH). We ana...

4 Watershed modeling requires accurate estimates of precipitation, however in some cases 5 it is necessary to simulate streamflow in a watershed for which there is no precipitation gauge 6 records within close proximity to the watershed. For such cases, we propose an approach for 7 estimating watershed-scale precipitation by combining (or fusing) gauge-based precipitation 8 time series with rad...

The distribution and movement of arsenic was investigated on the Aberjona watershed in eastern Massachusetts for the purpose of identifying where and by what processes present and past human exposures to this element could have occurred. It was found that although most of the arsenic was originally released in the headwaters of the watershed, extensive migration had occurred, and the potential ...

[1] Watershed-scale water quality models involve substantial uncertainty in model output because of sparse water quality observations and other sources of uncertainty. Assessing the uncertainty is very important for those who use the models to support management decision making. Systematic uncertainty analysis for these models has rarely been done and remains a major challenge. This study aimed...

The results of distributed watershed models could be sensitive to spatial and temporal scales at which inputs and model parameters are aggregated. This paper reports findings of a detailed sensitivity analysis conducted on the U.S. Department of Agriculture’s distributed watershed simulation model, known as the Soil and Water Assessment Tool (SWAT). The Big Creek Watershed, located in southern ...

Several best management practices (BMPs) have been implemented through Water Quality Management Plans (WQMPs) in the West Fork Watershed of Trinity River Basin in Texas, USA, where nonpoint source pollution is a serious concern. Major sources of pollution are sediment erosion and nutrients. The objective of this study was to evaluate the long-term impact of implementation of WQMPs on nonpoint s...

Because hydrologic responses of an agricultural watershed are influenced by many natural and man-made factors including pond/reservoir, management practices, and/or irrigation/drainage, strategies of hydrological modeling for the watershed must be case-dependent and thus carefully designed to effectively reflect their roles as critical hydrologic components in simulation processes. In this stud...

This project outlines procedures and resources used on the construction of polycyclic aromatic hydrocarbon (PAH) susceptibility model. The PAH susceptibility is due to PAH loading from impervious surface features in the watershed. The susceptibility model determines areas in the watershed which contribute to PAH loading. These hotspots represent areas that should be closely monitored, as they h...

Watershed is not simply the hydrological unit but also socio-political-ecological entity which plays crucial role in determining food, social, and economical security and provides life support services to rural people. The criteria for selecting watershed size also depend on the objectives of the development and terrain slope. A large watershed can be managed in plain valley areas or where fore...

In this paper, a formal de"nition and a new algorithmic technique for the watershed transformation is presented. The novelty of the approach is to adapt the connected component operator to solve the watershed segmentation problem. The resulting algorithm is independent of the number of grey-levels, employs simple data structures, requires less error prone memory management, and issues a lower c...