Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/11/2012
Publication Date: 8/15/2012
Citation: Jeong, J., Kannan, N., Arnold, J.G. 2012. Effects of urbanization and climate change on stream health in north-central Texas. Journal of Environmental Quality. doi:10.2134/jeq2011.0345. Interpretive Summary: Stream health can be determined by analyzing species of fish and micro-invertebrates, the condition of riparian vegetation, and stream degradation. In this study, we quantified stream health changes caused by urbanization and climate change in the Dallas-Fort Worth metropolitan area. Two widely accepted stream health indicators were used that utilize daily stream flow, sediment and water quality from: 1) measured flow gages, and 2) the Soil and Water Assessment Tool (SWAT) watershed model. The results indicated that urbanization has negative inputs on stream health caused by increased floods and droughts. Also, potential warmer and dryer climate conditions has severe negative input on stream health in the Dallas-Fort Worth area. The approach developed in this study was determined to be a potentially useful tool in estimating the input of land use and climate on stream health at the watershed scale.
Technical Abstract: Estimation of stream health involves the analysis of changes in aquatic species, riparian vegetation, micro-invertebrates, and channel degradation due to hydrologic changes occurring from anthropogenic activities. In this study, we quantified stream health changes arising from urbanization and climate change using a combination of the widely accepted Indicators of Hydrologic Alteration (IHA) and Dundee Hydrologic Regime Assessment Method (DHRAM) on a rapidly urbanized watershed in the Dallas-Fort Worth metropolitan area in Texas. Historical flow data were split into pre-alteration and post-alteration periods. The influence of climate change on stream health was analyzed by dividing the precipitation data into three groups of dry, average, and wet conditions based on recorded annual precipitation. Hydrologic indicators were evaluated for all three of the climate scenarios to estimate the stream health changes brought about by climate change. The effect of urbanization on stream health was analyzed for a specific sub watershed where urbanization occurred dramatically but no stream flow data were available using the widely used watershed-scale Soil and Water Assessment Tool (SWAT) model. The results of this study identify negative impacts to stream health with increasing urbanization and indicate that dry weather has more impact on stream health than wet weather. The IHA-DHRAM approach and SWAT model prove to be useful tools to estimate stream health at the watershed scale.