Showing papers by "Timothy O. Randhir published in 2009"

Urbanization effects on watershed habitat potential: a multivariate assessment of thresholds and interactions

Abstract: A watershed-based assessment is used to assess the effect of urbanization on vertebrate habitat potential in Westfield River Watershed in Massachusetts, USA. A spatial analysis is used to develop urban indicators and habitat potential for each subbasin in the watershed. It is observed that threshold effect of urbanization on habitat potential of vertebrates is at 10 to 12 percent impervious cover. Amphibian habitat is influenced by available open space and land use disturbance in the watershed. The reptile habitat is sensitive to impervious coverage and land use disturbance, and decreased with fragmentation. The habitat for birds is influenced by land use disturbance, human population densities, size of forest patch, and open space in the watershed. Mammal habitat is influenced by human population density, land use disturbance, and fragmentation. A watershed-based assessment is useful to identify critical areas of high urban influence. Threshold values and nature of interactions between urbanization and habitat are assessed and used in policy recommendations. Policies and practices that minimize effects of urbanization in the watershed include impervious taxes, zoning policies, and open space protection. The need for provision of education and information on the relationship between urbanization and habitat potential is emphasized for sustainable use of watershed resources. Copyright © 2009 John Wiley & Sons, Ltd.

Multiattribute optimization of restoration options: Designing incentives for watershed management

Abstract: [1] Watershed restoration requires careful assessment of impairment in ecosystem attributes to design appropriate conservation policies. This study applies a multiattribute optimization framework for evaluating relative gains in restoration based on potential improvements in economic and environmental attributes related to water quality, habitat, and urbanization. Policy mechanisms through direct compensation of restoration activities are evaluated based on single-attribute and multiattribute optimization and watershed response to varying levels of restoration incentives. Results indicate that tradeoffs in economic and environmental objectives are critical to identifying optimal restoration strategies at a watershed scale. The multiattribute optimization method developed in this study balances levels of multiple attributes and reflects tradeoffs in preferences for each attribute. Through an evaluation of a variety of attributes for relative gains and costs, opportunities exist for strategic selection of restoration activities in subwatersheds. The multiattribute method is found to be superior to the single-objective method in incorporation of tradeoffs, balancing economic and environmental impacts, and development of participatory solutions. Multiattribute assessment and policies are important for cost-effective and consensus-based watershed restoration practices.

Watershed-Scale Tradeoffs in Water Quantity and Quality Attributes for Conservation Policy

Abstract: Information on tradeoffs among water quantity and quality attributes at a watershed scale is important in developing effective watershed conservation policies. Assessment of these multiattribute tradeoffs, a focus of this study, is often a low priority in policy design. A combination of simulation modeling and statistical assessment was used to evaluate the significance of relationships among runoff, sediment, nitrate, and phosphorus loading in 115 subwatersheds of the Blackstone River Watershed in southern New England. We observed high variability in rates of runoff, nitrate, phosphorus, and sediment loading among subwatersheds. Results of the regression analysis indicate a high correlation between nitrate and surface runoff, emphasizing the importance of stormwater management in mitigating nutrient loads. A significant relationship exists between mineral phosphorus and sediment yield in watersheds that could inform strategies to mitigate eutrophication problems in phosphorus-limited systems such as some inland water bodies. The tradeoff analysis proposed can be used in policy design and to assess the implications of various policies to address multiple pollutants.