|KUMAR, S. - University Of Texas - El Paso
|GODREJ, A.N. - Virginia Tech
|GRIZZARD, T.J. - Virginia Tech
|POST, H.E. - Virginia Tech
Submitted to: Journal of Water Resources Planning and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/7/2017
Publication Date: 5/18/2018
Citation: Kumar, S., Moglen, G.E., Godrej, A., Grizzard, T., Post, H. 2018. Trends in water yield under climate change and urbanization in the U.S. mid-atlantic region. Journal of Water Resources Planning and Management. https://doi.org/10.1061/(ASCE)WR.1943-5452.0000937.
Interpretive Summary: This manuscripts focuses on the water budget for ten watersheds in the Washington, DC metropolitan area. Four watersheds were dominated by agricultural and forested land uses. Five watersheds were urban, and one transitioned from agriculture/forest to urban during the 40-year study period. Differences in water budget among runoff and evapotranspiration were noted between the different land use compositions examined. Trends in water yield, the fraction of precipitation that is converted to streamflow, were also observed. These trends reflect changes to both land use and evapotranspiration - the latter process being affected by warming temperatures from climate change. This paper provides anecdotal evidence of changing yield patterns that is relevant to watershed model calibration, watershed monitoring activities, and possible changes in future water supply.
Technical Abstract: Changes in climate and land use are two primary drivers of hydrologic adjustment. This study analyzes forty years of water resources data for ten watersheds in the Washington, DC, metropolitan area to quantify the impact of climate change and urbanization on water yield. The watersheds investigated have experienced varying degrees of land use change, from relatively little change to rapid and extensive urbanization. Comparing the data trends for different watersheds allows the separation of effects due largely to climate from those due to land use change. Predominantly rural watersheds show a steady decline in annual water yield while predominantly urban watersheds do not show any similar trend with time. Separating the year into growing versus non-growing seasons reveals that limited evapotranspiration from urban surfaces during the growing season or the general effects of a leaking water distribution network may mask the reductions in water yield in urban watersheds from changing climate. These analyses provide hydrological evidence for generally enhanced evapotranspiration and complex interactions between concurrent climate change and urbanization within the study area.