Managing Groundwater Levels in an Agricultural Area with Peat Soils

Abstract

The Hula Decision Support System (HDSS) is designed to aid Hula site operators in managing groundwater levels in the Hula Lake region of Israel. Groundwater levels are managed by controlling water levels by using adjustable dams in a grid of drainage canals and by the timing and intensity of irrigation. Water levels in the canals are controlled by a set of hydraulic structures. Groundwater levels are to be maintained within a specified range to minimize decomposition and subsidence of the peat soils, ensure year-round green cover of the area, and avoid saturation conditions in the crop root zone, thereby allowing farmers to continue cultivation of their fields. The management module for the HDSS performs optimization with the following two objectives: (1) minimize deviation from the specified groundwater target level, and (2) minimize supply of water from the Jordan River to the Hula drainage canals (water quantity is limited). The second objective is achieved indirectly in the HDSS by determining the dam settings and irrigation quantity and timing over a period of eight weeks and then solving again whenever conditions change. The results are checked by simulation using MODFLOW within the GMS modeling package. The procedure is demonstrated and analyzed.