Preliminary Conceptual Model of Groundwater level Response to Evapotranspiration in the Whitewater Basin, Kansas
Abstract
Hydrologic Studies are being proposed in the 1100 sq. km. Whitewater Basin in South-Central Kansas at scales ranging from that of a single link-hillslope system to the entire basin, as part of the Hydro-Kansas research program. This semi-arid 7th order basin is characterized by well-defined riparian zones along the banks of higher-order streams. A thick low-permeability geological unit extends to the ground surface in most of the basin, except adjacent to the stream network, where there are alluvial deposits. The groundwater flow system in these alluvial deposits is supplied by seepage losses from the stream and loses water to evapotranspiration by riparian vegetation. With the objective of estimating evapotranspiration rates as a closure term in the water balance at the scale of a single link-hillslope system, we are in the process of designing a piezometer network to estimate changes in groundwater storage and fluxes from the stream into the alluvium. The diurnal trends in evapotranspiration could potentially lead to diurnal fluctuations in groundwater levels, as has been observed at several other sites over the last 70 years. We present a simple conceptual model of stream-aquifer interaction and evapotranspiration that was developed to aid in the design of the piezometer network. The evapotranspiration rates in this model are specified using a recently developed biological allometric relationship, which provides bounds on areally integrated rates under conditions of no moisture deficit. After the piezometer network is installed in the field, the water balance estimates of evapotranspiration will be compared to ththose predicted by the allometric relationships, and to LIDAR and aircraft based measurements that are being developed in related projects. We also present a parametric analysis of the controls imposed by riparian zone width on stream-aquifer interactions to gain insights into the potential behavior across a range of stream orders
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2005
- Bibcode:
- 2005AGUFM.H31J..03M
- Keywords:
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- 1813 Eco-hydrology;
- 1818 Evapotranspiration;
- 1829 Groundwater hydrology;
- 1830 Groundwater/surface water interaction;
- 1836 Hydrological cycles and budgets (1218;
- 1655)