HR: 1330h
AN: NB33G-06 [Abstracts]
TI: The influence of catchment land use on hydrograph dynamics and implications for stream biological assemblages
AU: Shuster, W D
EM: shuster.william@epa.gov
AF: USEPA-NRMRL, ML 498 USEPA-NRMRL
26 W Martin Luther King, Cincinnati, OH 45268 United States
AU: * Zhang, Y
EM: zhang.yu@epa.gov
AF: Oak Ridge Institute for Science and Education, ML 498 USEPA-NRMRL
26 W Martin Luther King, Cincinnai, OH 45268 United States
AB:
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
km2. 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 particlar 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.
1
DE: 1800 HYDROLOGY
DE: 1803 Anthropogenic effects
DE: 1860 Runoff and streamflow
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly