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How Do Land-Use and Climate Change Affect Watershed Health? A Scenario-Based Analysis
Citation:
Hoque, Y., C. Raj, M. Hantush, I. Chaubey, AND R. Govindaraju. How Do Land-Use and Climate Change Affect Watershed Health? A Scenario-Based Analysis. M. M. Aral (ed.), Water Quality, Exposure and Health. Springer, New York, NY, 6(1-2):19-33, (2014).
Impact/Purpose:
The overall goal of this study was to conduct an R-R-V indicator-based risk analysis to quantify watershed health as it is related to water quality for a candidate watershed under multiple land-use and climate change scenarios. Specific objectives to meet this overall goal include (1) Estimation of R-R-V values for selected water quality constituents under projections of multiple land-use and climate change scenarios; (2) Comparison of R-R-V values between the baseline case and projected scenarios and assess their influence on watershed health.
Description:
With the growing emphasis on biofuel crops and potential impacts of climate variability and change, there is a need to quantify their effects on hydrological processes for developing watershed management plans. Environmental consequences are currently estimated by utilizing computer models such as Soil and Water Assessment Tool (SWAT) to simulate watershed hydrology under projected climate and land-use scenarios to assess the effect on water quantity and/or quality. Such studies have largely been deterministic in nature, with the focus being on whether hydrologic variables such as runoff, sediment and/or nutrient loads increase or decrease from the baseline case under projected scenarios. However, studying how these changes would affect watershed health in a risk-based framework has not been attempted. In this study, impacts of several projected land-use and climate change scenarios on the health of the Wildcat Creek watershed in Indiana have been assessed through three risk indicators, namely reliability-resilience-vulnerability (R-R-V). Results indicate that cultivation of biofuel crops such as Miscanthus and switchgrass has the potential to improve risk indicator values with respect to sediment, total N and total P. Climate change scenarios that involved rising precipitation levels were found to negatively impact watershed health indicators. Trends of water quality constituents under risk-based watershed health assessment revealed nuances not readily apparent from deterministic asessments alone. For example, while biofuel crop cultivation reduced total N loads under all hypothetical land-use scenarils examined in this study, watershed vulnerability in terms of total N also rose in some of those scenarios. Risk-based analyses coupled with deterministic methods are needed for a more comprehensive assessment of the health of a watershed under projected scenarios.
