2025 CSDMS meeting-052
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NDVI as a proxy for Hydrological Drought Monitoring around Cape Town, South Africa
Louis Quigley,
(He/Him),University of Illinois Chicago Chicago Illinois, United States. lquigl3@uic.edu
Kerry Callaghan, University of Illinois Chicago Chicago Illinois, United States. kerryc@uic.edu
Groundwater is a key water source, particularly in arid regions such as southern Africa, but direct monitoring is limited. Groundwater monitoring becomes increasingly valuable as rising water demand meets more frequent and severe droughts under climate change. This project explores the potential of vegetation indices, particularly NDVI, as a proxy for hydrological drought . We calculate monthly NDVI anomalies at a 250 m spatial resolution and 16 day composite temporal resolution from NASA’s MOD13Q1 dataset over a 2.5° × 2.5° area covering Cape Town in South Africa. These anomalies are plotted over time and compared with a recorded drought periods to assess vegetation response to water scarcity. The high spatiotemporal resolution of NDVI products and the satellite imagery from which they are derived makes them useful for understanding where hydrological drought may be occurring, even in the absence of groundwater wells. In ongoing work, we plan to simulate changing water table elevations at a monthly timescale using the Water Table Model (WTM) to determine how local and regional water table elevations respond to drought conditions. Further work will incorporate well data and lake surface elevations to validate model accuracy. This approach aims to develop an accessible method for groundwater monitoring and drought assessment in data-limited regions.
