Use of Stage Data to Characterize Hydrologic Conditions in an Urbanizing Environment

 

Gerard McMahon ¹, Jerad D. Bales ¹, James F. Coles ², Elise M.P. Giddings ¹, and Humbert Zappia ³

¹U.S. Geological Survey, 3916 Sunset Ridge Road, Raleigh, North Carolina 27608, USA
²U.S. Environmental Protection Agency, 1 Congress Street, Suite 1100 (HBS), Boston, Massachusetts 02114, USA
³U.S. Geological Survey, 2350 Fairlane Drive, Suite 120, Montgomery, Alabama 36116, USA

ABSTRACT.— This paper presents the results of a study on the use of continuous stage data to describe the relation between urban development and three aspects of hydrologic condition that are thought to influence stream ecosystems--overall stage variability, stream flashiness, and the duration of extreme-stage conditions. This relation is examined using data from more than 70 watersheds in 3 contrasting environmental settings--the humid Northeast (the metropolitan Boston, Massachusetts, area); the very humid Southeast (the metropolitan Birmingham, Alabama, area); and the semiarid West (the metropolitan Salt Lake City, Utah, area). Results from the Birmingham and Boston studies provide evidence linking increased urbanization with stream flashiness. Fragmentation of developed land-cover patches appears to ameliorate the effects of urbanization on overall variability and flashiness. There was less success in relating urbanization and streamflow conditions in the Salt Lake City study. A related investigation of 6 North Carolina sites with long-term discharge and stage data indicated that hydrologic-condition metrics developed using continuous stage data are comparable to flow-based metrics, particularly for stream flashiness measures.