Proper identification of water quality conditions in a river system based on limited observations is an essential task for meeting the goals of environmental management. Various classification methods have been used for estimating the changing status and usability of surface water in river basins. However, a discrepancy frequently arises from the lack of a clear distinction between each water u...

This paper describes a comprehensive stream-riparian modeling system to evaluate the effects of channel-riparian zones on stream Total Maximum Daily Loads (TMDLs). Nonpoint source pollutants emanating from agricultural fields are major contributors to the ecological impairment of stream channels. Nutrients and sediments are the principle sources of surface water impairment. The edge-of-field sy...

Natural resource managers face complex challenges in addressing non-point source water pollution. A participatory modeling approach was applied in the St. Albans Bay watershed to identify the most effective phosphorus control options to achieve the load reductions required by the Lake Champlain Phosphorus Total Maximum Daily Load (TMDL). Stakeholders participated in the collection of data in th...

Total Maximum Daily Load (TMDL) analyses of lakes and reservoirs with nutrient impairments commonly identify onsite wastewater treatment systems (i.e. septic systems) as an important potential source of nitrogen (N). In most cases, however, the contribution from on-site wastewater systems (OWSs) is difficult to estimate because of uncertainty about how much of the N is lost due to denitrificati...

The increasing number of polluted watersheds and water bodies with total maximum daily loads (TMDLs) has resulted in increased research to find methods that effectively and universally identify fecal pollution sources. A fundamental requirement to identify such methods is understanding the microbial and chemical processes that influence fate and transport of fecal indicators from various source...

Environmental decision support systems (EDSSs) are an emerging tool used to integrate the evaluation of highly complex and interrelated physicochemical, biological, hydrological, social, and economic aspects of environmental problems. An EDSS approach is developed to address hot-spot concerns for a water quality trading program intended to implement the total maximum daily load (TMDL) for phosp...

Digital elevation models (DEMs) are a useful data source for the automatic delineation of flow paths, sub watersheds and flow networks for hydrologic modeling. Digital representation of the flow network is central to distributed hydrologic models because it encodes the model element linkages through which flow is routed to the outlet. The scale (drainage density) of the flow network, used contr...

Estimation of surface runoff from a watershed is a pre-requisite to determine pollutant loss, develop regulatory measures such as Total Maximum Daily Loads (TMDL), and to forecast the water supply during spring and early summer (Mahabir et al., 2003). Regression models used for forecasting runoff for water supply often do not perform well especially in forecasting low and average runoff events,...

In this paper, we present an Internet-based, Bayesian Decision Network engine to aid watershed stakeholders in collaborative decision-making. Recent years have seen an increased emphasis on including all affected parties in the process of making water resources and water quality management decisions (as in the TMDL program). Given the complexity of the models and data analysis tools that are ty...

This paper describes the development of a comprehensive flow and salinity monitoring system and application of a decision support system (DSS) to improve management of seasonal wetlands in the San Joaquin Valley of California. The Environmental Protection Agency regulates salinity discharges from non-point sources to the San Joaquin River using a procedure known as the total maximum daily load ...