Groundwater recharge and discharge analysis for land use conditions suitable for the hydrology and ecology of semiarid regions

Land use is critical for the hydrology of arid/semiarid regions with fragile/valuable ecosystems. Using Western Jilin as proxy for arid/semiarid, four land use conditions were investigated for the sustainability of fragile/valuable ecosystems – land use conditions for 1930 (pre-development), 2010 (post-development), forestland and grassland. For forestland/grassland, barren/bare-lands and land surfaces with ≥10% slope in 2010 were replaced with grass and forest. Error analysis showed good agreements among the model-simulated and field-measured values, with average error <10%. Shifting from 1930 to 2010 land use condition decreased annual recharge and discharge by 17.09% (21.46 mm/yr or 1.01 × 10⁹m³) and 34.14% (10.03 mm/yr or 4.70 × 10⁸m³), respectively, in the 4.69 × 10¹⁰m² study area. Rehabilitating 2010 land use with forest increased recharge and discharge, respectively, by 6.25% (6.51 mm/yr or 3.05 × 10⁸m³) and 12.82% (2.88 mm/yr or 1.16 × 10⁸m³). Replacing the forest with grass increased recharge and discharge, respectively, by 15.22% (15.85 mm/yr or 7.43 × 10⁸m³) and 35.85% (6.93 mm/yr or 3.25 × 10⁸m³). Although pre-development land use condition was most conducive, grass performed better than forest in the study area. Rehabilitation with grass little affects food production in the region, and is thus applicable to other arid/semiarid regions.