We analyzed the complex dynamics that are involved the groundwater level variations due to the episodic rainfall supply in the Ionian coastal plain surficial aquifer located in Southern Italy. In this aquifer, as a consequence of the particular hydrogeological framework, both direct and lateral recharge mechanisms coexist. Hence, the dynamics of groundwater level variations are quite complex and strongly non-linear. Our focus was essentially on the short-term behavior of groundwater levels, with a specific analysis on episodic rainfall events. To model these dynamics, due to the presence of the preferential pathways in the infiltration processes, a kinematic dispersion wave model was used. Specifically, a one-dimensional and non-linear particle-based numerical model was developed. It uses ideal particles with constant water volume travel, according to celerity and hydraulic dispersion, to simulate the infiltration rate wave through the vadose zone. The infiltration rate that reaches the water table represents the input function to evaluate the aquifer groundwater level fluctuations. As a consequence of the special lithological and storage capacity characteristics of the surficial layers, groundwater flow conditions change from unconfined to confined. The developed model analyzes the direct groundwater supply under natural conditions, including episodic rainfall, and it has been validated using a high-resolution time series of rainfall data and groundwater level obtained from the monitoring station Terra Montonata.

中文翻译：

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意大利南部地表含水层偶发性降雨事件期间复杂地下水位动态的建模

我们分析了由于位于意大利南部爱奥尼亚沿海平原地表含水层的间歇性降雨供应而引起的地下水位变化的复杂动态。在这个含水层中，由于特定的水文地质框架，直接和横向补给机制并存。因此，地下水位变化的动态非常复杂且具有很强的非线性。我们的重点主要是地下水位的短期行为，并对偶发性降雨事件进行了具体分析。为了模拟这些动力学，由于在渗透过程中存在优先路径，使用了运动色散波模型。具体来说，开发了一个一维和非线性的基于粒子的数值模型。它使用具有恒定水体积行程的理想粒子，根据速度和水力弥散，模拟通过渗流带的下渗率波。到达地下水位的入渗率代表了评价含水层地下水位波动的输入函数。由于地表层的特殊岩性和储存能力特征，地下水流动条件从无限制变为有限制。开发的模型分析了自然条件下的直接地下水供应，包括偶发性降雨，并且已经使用从监测站 Terra Montonata 获得的降雨数据和地下水位的高分辨率时间序列进行了验证。到达地下水位的入渗率代表了评价含水层地下水位波动的输入函数。由于地表层的特殊岩性和储存能力特征，地下水流动条件从无限制变为有限制。开发的模型分析了自然条件下的直接地下水供应，包括偶发性降雨，并且已经使用从监测站 Terra Montonata 获得的降雨数据和地下水位的高分辨率时间序列进行了验证。到达地下水位的入渗率代表了评价含水层地下水位波动的输入函数。由于地表层的特殊岩性和储存能力特征，地下水流动条件从无限制变为有限制。开发的模型分析了自然条件下的直接地下水供应，包括偶发性降雨，并且已经使用从监测站 Terra Montonata 获得的降雨数据和地下水位的高分辨率时间序列进行了验证。