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THE INFLUENCE OF CATCHMENT LAND USE ON HYDROGRAPH DYNAMICS AND IMPLICATIONS FOR STREAM BIOLOGICAL ASSEMBLAGES
Citation:
SHUSTER, W. D. AND Y. ZHANG. THE INFLUENCE OF CATCHMENT LAND USE ON HYDROGRAPH DYNAMICS AND IMPLICATIONS FOR STREAM BIOLOGICAL ASSEMBLAGES. Presented at 2005 American Geophysical Union Joint Assembly, New Orleans, LA, May 23 - 25, 2005.
Impact/Purpose:
To inform the public.
Description:
Catchment land use impacts the rise and fall dynamic of hydrographs, and may also help explain variation in biological assemblages known to be sensitive to flow regime. We collected continuous stream depth records for the 2002 water year (5 min. intervals) from eight streams draining catchments ranging in size from 17 to 58 km^2 in the Little Miami River (Ohio) watershed. Correspondent data for stream biological communities was collected on an annual basis from 1999 to 2002. High-resolution aerial photos from 2002 showed that land use over the eight catchments fell over a gradient in the extent of unvegetated, barren land, which ranged from 2 to 14 percent. Storm hydrographs were analyzed for duration and rate constants, and for both rising and falling limbs. Although we expected moderate urbanization in certain catchments to affect rise rates, we were surprised to find that no particular type or percentage land use correlated with characteristics of the rising limb. An increased proportion of barren land, however, significantly decreased the duration of the falling limb relaxation curve and its mass. The degree to which the unprotected barren areas emulate impervious surface may have increased the proportion of precipitation converted to runoff during storm events, limiting the potential for longer term recharge. This change in hydrology affected habitat availability and quality, which we furthermore discuss in the context of effects on stream biological assemblages.