HR: 09:45h
AN: H21I-07    [Abstracts]
TI: Inference of Stream Network Fragmentation Patterns from Ground Water - Surface Water Interactions on the High Plains Aquifer
AU: * Chandler, D G
EM: dgc@ksu.edu
AF: Civil Engineering Kansas State University, Fiedler Hall, Manhattan, KS 66507, United States
AU: Yang, X
EM: xiaoying@ksu.edu
AF: Civil Engineering Kansas State University, Fiedler Hall, Manhattan, KS 66507, United States
AU: Steward, D R
EM: steward@ksu.edu
AF: Civil Engineering Kansas State University, Fiedler Hall, Manhattan, KS 66507, United States
AU: Gido, K
EM: kgido@ksu.edu
AF: Division of Biology Kansas State University, Ackert Hall, Manhattan, KS 66507, United States
AB: Stream networks in the Great Plains integrate fluxes from precipitation as surface runoff in discrete events and groundwater as base flow. Changes in land cover and agronomic practices and development of ground water resources to support irrigated agriculture have resulted in profound changes in the occurrence and magnitude of stream flows, especially near the Ogallala aquifer, where precipitation is low. These changes have demonstrably altered the aquatic habitat of western Kansas, with documented changes in fish populations, riparian communities and groundwater quality due to stream transmission losses. Forecasting future changes in aquatic and riparian ecology and groundwater quality requires a large scale spatially explicit model of groundwater- surface water interaction. In this study, we combine historical data on land use, stream flow, production well development and groundwater level observations with groundwater elevation modeling to support a geospatial framework for assessing changes in refugia for aquatic species in four rivers in western Kansas between 1965 and 2005. Decreased frequency and duration of streamflow occurred in all rivers, but the extent of change depended on the geomorphology of the river basin and the extent of groundwater development. In the absence of streamflow, refugia for aquatic species were defined as the stream reaches below the phreatic surface of the regional aquifer. Changes in extent, location and degree of fragmentation of gaining reaches was found to be a strong predictor of surface water occurrence during drought and a robust hydrological template for the analysis of changes in recharge to alluvial and regional aquifers and riparian and aquatic habitat.
DE: 1813 Eco-hydrology
DE: 1830 Groundwater/surface water interaction
DE: 1834 Human impacts
SC: Hydrology [H]
MN: 2007 Fall Meeting