Water availability in semi-arid regions is threatened by climate variability, land use dynamics and growing water demand, highlighting the need for long term, spatially explicit management planning. This study applies the InVEST model to the North fork Red River Basin, the basin draining to Lake Lugert altus, and the main water source for Jackson County, OK. Using multi-decadal climate and land use data for five representative years (1985, 1995, 2005, 2015, and 2023) we analyzed hydraulic responses to climate variability and identified priority sub-watersheds relevant to regional water management. Model calibration and sensitivity analyses highlighted the strong influence of subsurface routing parameters on baseflow estimation. Validation against observed streamflow demonstrated robust model performance, with simulated quick flow corresponding with observed discharge, with R2 ranging from 0.86 to 0.91 and Nash-Sutcliff efficiency values between 0.71 to 0.88. Baseflow separation (a = 0.850, BFImax = 0.20) using Eckhardt separation method indicated that streamflow in the basin is predominantly runoff driven, with limited and rapidly recessing groundwater contributions, consistent with semi-arid hydrologic behavior. Results demonstrate strong spatial variability in water yield components, with higher quickflow, baseflow, and local recharge consistently concentrated in the downstream and south-eastern sub-watersheds, including those contributing to the Lugert-Altus reservoir. Temporally, water yield peaked during the mid-1990s, followed by basin-wide decline in recharge and baseflow through 2023, indicating increasing vulnerability to drought and hydroclimatic extremes. These findings provide insights into the dynamics between water supply and areas of high demand, highlighting priority locations for water resource management and opportunities to enhance climate resilience. By linking hydrologic ecosystem service dynamics to regional water use dependence, this study supports adaptive planning strategies for sustaining water security in semi-arid agricultural watersheds under future climate uncertainties.