HR: 0800h
AN: H21E-1072    [Abstracts]
TI: Recharge, Upflux, and Water Table Fluctuations for Shallow Water Table Conditions
AU: * Sanjay, S
EM: sshukla@ifas.ufl.edu
AF: University of Florida, Agricultural and Biological Engineering, Southwest Florida Research and Education Center, 2686 State road 29 N, immokalee, Fl 34142 United States
AU: Jaber, F H
EM: fhjaber@ifas.ufl.edu
AF: University of Florida, Agricultural and Biological Engineering, Southwest Florida Research and Education Center, 2686 State road 29 N, immokalee, Fl 34142 United States
AB: Recharge to groundwater and upflux were estimated for shallow water tables that have unexpectedly high rises in response to small water input. This phenomenon, known as the reverse Wieringermeer effect, renders the conventional recharge and upflux calculations, using specific yield, inaccurate. Water balance and soil moisture data from five large lysimeters, were used to develop a method for calculating recharge and upflux. Regression analysis was used to correlate the water table fluctuations to rainfall and irrigation input and withdrawals for the lysimeters. Three lysimeters (drip lysimeters) were irrigated through a combination of drip and seepage irrigation and two lysimeters (seepage lysimeters) were irrigated using seepage irrigation method. Rainfall and seepage irrigation input was highly correlated with water table rise in all lysimeters. Drip irrigation input had a low correlation for all lysimeters because of the effect of evaporation on the percolation rate. Drainage was highly correlated with water table drops in drip lysimeters while the correlation in the seepage lysimeters was low. The low correlation for seepage lysimeters is attributed to air entrapment in the groundwater during the high volume seepage irrigation events. These relationships could provide effective prediction tools for irrigation and drainage management under shallow water table conditions.
DE: 1818 Evapotranspiration
DE: 1829 Groundwater hydrology
DE: 1836 Hydrologic budget (1655)
DE: 1866 Soil moisture
DE: 1875 Unsaturated zone
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting