Groundwater is an important source of water supply for several socioeconomic sectors. In particular, heterogeneous carbonate aquifers are an important potential reservoir of groundwater resources. The Matmata carbonate aquifer, located in southern Tunisia, suffers from over abstraction and severe anthropogenic pressure. This study aims to estimate diffusive recharge rates using climate and soil datasets, and proposes a combination of CMB techniques and numerical simulation methods. Groundwater chloride mass balance and numerical simulations were best practices for achieving these goals. The Hydrus-1D model was applied, calibrated and validated with soil water content measured at different depths and using long-term, diurnal-scale field and climate data. The results highlight that Richard's retention parameters give a close correlation with the observed saturated moisture content with RMSE of 0.07. The calculated evaporation is around 22.5 mm for the entire study period, and the contribution of rainfall to infiltration, which was estimated at 9.8 mm as 8.4%. The CMB model shows a recent recharge rate 4.83 mm. yr⁻¹, corresponding to a groundwater recharge rate of 5.84 % of precipitation. Groundwater recharge estimation is one of the most important concepts of water balance, and its assessment is crucial for groundwater management and protection.

地下水是多个社会经济部门的重要供水来源。特别是非均质碳酸盐岩含水层是地下水资源的重要潜在储库。位于突尼斯南部的马特马塔碳酸盐含水层遭受过度抽取和严重的人为压力。本研究旨在利用气候和土壤数据集来估计扩散补给率，并提出了 CMB 技术和数值模拟方法的结合。地下水氯化物质量平衡和数值模拟是实现这些目标的最佳实践。Hydrus-1D 模型通过在不同深度测量的土壤含水量并使用长期、日尺度的现场和气候数据进行应用、校准和验证。结果表明，Richard 的保留参数与观测到的饱和水分含量密切相关，RMSE 为 0.07。整个研究期间的计算蒸发量约为 22.5 毫米，降雨对入渗的贡献估计为 9.8 毫米，占 8.4%。CMB 模型显示最近的充电速率为 4.83 毫米。yr ^-1，对应地下水补给率为降水量的5.84%。地下水补给估算是水平衡最重要的概念之一，其评估对于地下水管理和保护至关重要。