Comprehensive Framework for Water Resources Degradation in the lower Boise River

Increasing concern for the degradation of water resources and their long-term sustainability has become more widespread across the United States over the past few decades. Water resources can be degraded by overuse, poorly designed urbanization or pollution from sources such as agricultural land and water use, wastewater treatment facility discharge, reservoir operations, and river channel alteration. Section 303(d) of the Clean Water Act (CWA) requires States to develop total maximum daily load (TMDL) for water bodies whose beneficial uses are impaired as a result of poor water quality. The lower Boise was added to Idaho's list of water-quality-limited streams in 1992. The EPA has developed total maximum daily load (TMDL) specifications for some of these waters. It is likely that the implementation of the TMDLs will require pollutant load reductions based on land uses in the region. This research is aimed to develop a better conceptual and practical understanding of water resource degradation, and the patterns of relationships governing its causation, impact and land use management in the lower Boise River. This study is ongoing and employed an interdisciplinary approach incorporating remote sensing, GIS, coupled with non-point source modeling, and Bayesian Decision Networks (BDN) to evaluate land-use management options to safeguard long-term resource sustainability. The study also used ground truth data and limited water quality measurements. The Agricultural Non-Point Source Pollution (AGNPS) and HYDRUS-1D models are implemented to compare different land parcels in terms of the amount of pollutants. The scenarios will be tested statistically using a suggested BDN. A generic BDN was constructed for all modeling units and a predictive analysis will be performed using a complete BDN to model decision impacts and perform sensitivity analysis.