loading page

Localizing Hydrological Drought Early Warning using In-situ Groundwater Sensors
  • +2
  • William Veness,
  • Adrian P. Butler,
  • Boris Fernando Ochoa-Tocachi,
  • Simon Moulds,
  • Wouter Buytaert
William Veness
Imperial College London

Corresponding Author:[email protected]

Author Profile
Adrian P. Butler
Imperial College of Science, Technology & Medicine
Author Profile
Boris Fernando Ochoa-Tocachi
Imperial College London
Author Profile
Simon Moulds
Imperial College London
Author Profile
Wouter Buytaert
Imperial College London
Author Profile

Abstract

Drought Early Warning Systems (DEWSs) aim to spatially monitor and forecast risk of water shortage to inform early, risk-mitigating interventions. However, due to the scarcity of in-situ monitoring in groundwater-dependent arid zones, spatial drought exposure is inferred using maps of satellite-based indicators such as rainfall anomalies, soil moisture and vegetation indices. On the local scale, these coarse-resolution proxy indicators provide a poor inference of groundwater availability. The improving affordability and technical capability of modern sensors significantly increases the feasibility of taking direct groundwater level measurements in data-scarce, arid regions on a larger scale. Here, we assess the potential of in-situ monitoring to provide a localized index of hydrological drought in Somaliland. We find that calibrating a lumped groundwater model with a short time series of high-frequency groundwater level observations substantially improves the quantification of local water availability when compared to satellite-based indices over the same validation period. By varying the calibration length between 1-30 weeks, we find that data collection beyond 5 weeks adds little to model calibration at all three wells. This suggests that a short monitoring campaign is suitable to improve estimations of local water availability during drought, and provide superior performance compared to regional-scale satellite-based indicators. A short calibration period has practical advantages, as it allows for the relocation of sensors and rapid characterization of a large number of wells. A monitoring system with this contextualized, local information can support earlier financing and better targeting of early actions than regional DEWSs.