99 D8. Groundwater Recharge and Unsaturated-zone Processes at Local and Regional Scales: A Reflection on Rick Healy's Legacy (Posters)

Monday, 23 September 2024
8:00 AM - 5:30 PM
Hall D

COUPLING PHYSICAL AND ISOTOPE HYDROLOGY TO ESTIMATE SEASONAL GROUNDWATER RECHARGE: CASE OF NERI RIVER WATERSHED, ETHIOPIA

Paper number: 99-3
Program: Technical Sessions
Time: 8:00 AM – 5:30 PM

Authors

Abstract

This study employs the WetSpass-M (Water and Energy Transfer between Soil, Plants, and Atmosphere under Steady-State Conditions) method to estimate seasonal groundwater recharge coupling with δ18O (Oxygen-18) mass balance seasonal groundwater recharge estimation method with a focus on the Neri River watershed in Ethiopia. The WetSpass model uses grid-based and database format (dbf) input parameters to estimate groundwater recharge. Conversely, the assessment of groundwater recharge based on the δ18O mass balance approach was conducted by examining groundwater and precipitation samples for stable oxygen and hydrogen isotopes. Seasonal variations in the leaf area index (LAI) and land use/cover (LULC) map of 2023 were used to estimate the recharge through the WetSpass-M model. The results of the physical hydrology approach revealed that 60.6% of the average groundwater recharge takes place from March through August, which is the rainy season, and the remaining 39.4% occurs from September through February, which is the dry season. In line with physical hydrology findings, the δ18O mass balance technique was also utilized to estimate groundwater recharge, revealing that 58.2% of recharge takes place during the rainy season and the remaining 41.8% during the dry season. The results of the study will assist local stakeholders and policymakers in creating a groundwater resource management strategy that is both sustainable and efficient for the watershed.

Geological Society of America Abstracts with Programs. Vol. 56, No. 5

doi: 10.1130/abs/2024AM-404830

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