MODFLOW and HYDRUS Modeling of Groundwater Supply Prospect Assessment for Distant Pastures in the Aksu River Middle Reaches

As in many regions across the world, southeastern Kazakhstan is subjected to ongoing water-resource depletion. The livestock sector is already a major natural water resource consumer, with groundwater use becoming its water supply strategy. Remote pasture infrastructure development requires new water resources to allow pasture area circulation. The distant pastures in the middle reach of the Aksu River consist of three pastures, with a total area of 32,450 ha and a permissible number of 3245 livestock heads. The HYDRUS-1D water transport model and MODFLOW groundwater-flow model simulated complex water infrastructure prospect hydrogeological scenarios to allow the consumption of 302.4 m³ per day for livestock keeping on pasturelands. During pumping for livestock watering, projected production well drawdowns were quantitatively evaluated. The findings show that the projected pumping flow rate equals 288 m³/day during the water consumption season and 95 m³/day outside the water consumption season. While the production wells on pastures No. 2 and No. 3 can be considered reliable, on pasture No. 1, an additional production well is needed. To maintain the production wells’ drawdowns to less than 6 m, a projected pumping flow rate reduction to 216 m³/day and 70 m³/day, respectively, is required.