A landscape hydrology approach to inform sustainable water resource management under a changing environment. A case study for the Kaleya River Catchment, Zambia

Abstract

STUDY REGION : Kaleya River Catchment in southern Zambia. STUDY FOCUS : The ability of a landscape hydrology approach to detect controls on water availability in a fragmented landscape to inform interventions under a changing environment was investigated. Simple and measurable climatic and landscape pattern attributes were analysed using change detection, trend analysis and backward variable elimination with Partial Least Squares Regression (PLSR) to identify controls on seasonal river flows and how landscape components could be enhanced to augment natural river flows. NEW HYDROLOGICAL INSIGHTS FOR THE REGION : Landscape pattern showed increasing fragmentation, expansion of irrigated cropland and reservoirs and loss of forestland. Significant increasing trends (p < 0.05) were observed for reference evapotranspiration (ETo), one-day maximum rainfall, coefficient of variation (CV) of rainfall, maximum dry spell length, and start of rains but not annual rainfall. Increased CV of rainfall, rainfall intensity and ETo were the main climatic stressors on river flows. Increased Percentage of Landscape (PLAND) of irrigated cropland, PLAND of reservoirs, Patch Density (PD) and Largest Patch Index (LPI) of reservoirs were the main landscape pattern stressors. Only the LPI of forestland positively explained seasonal river flows. Water resource interventions in the region must adapt more to changing seasonal rainfall characteristics than to annual rainfall totals. Additionally, regeneration of larger forest patches could improve river flows. The approach can be applied in other regions.