Urban Stormwater Temperature Surges: A Central US Watershed Study

Hydrology

Sean J. Zeiger¹  Jason A. Hubbart¹ 

关键词: stream water temperature;    experimental watershed study;    urban heat island;    storm water runoff;    water quality;   

DOI  :  10.3390/hydrology2040193

来源: mdpi

【 摘 要 】

Impacts of urban land use can include increased stormwater runoff temperature (T_w) leading to receiving water quality impairment. There is therefore a need to target and mitigate sources of thermal pollution in urban areas. However, complex relationships between urban development, stormwater runoff and stream water heating processes are poorly understood. A nested-scale experimental watershed study design was used to investigate stormwater runoff temperature impacts to receiving waters in a representative mixed-use urbanizing watershed of the central US. Daily maximum T_w exceeded 35.0 °C (threshold for potential mortality of warm-water biota) at an urban monitoring site for a total of five days during the study period (2011–2013). Sudden increases of more than 1.0 °C within a 15 min time interval of T_w following summer thunderstorms were significantly correlated (CI = 95%; p < 0.01) to cumulative percent urban land use (r² = 0.98; n = 29). Differences in mean T_w between monitoring sites were significantly correlated (CI = 95%; p = 0.02) to urban land use practices, stream distance and increasing discharge. The effects of the 2012 Midwest USA drought and land use on T_w were also observed with maximum T_w 4.0 °C higher at an urban monitoring site relative to a rural site for 10.5 h. The current work provides quantitative evidence of acute increases in T_w related to urban land use. Results better inform land managers wishing to create management strategies designed to preserve suitable thermal stream habitats in urbanizing watersheds.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.