Estimating and Forecasting Time?Varying Groundwater Recharge in Fractured Rock: A State?Space Formulation With Preferential and Diffuse Flow to the Water Table

Rapid infiltration following precipitation may result in groundwater contamination from surface contaminants or pathogens. In fractured rock, can migrate rapidly to points of withdrawals. contrast the temporal availability quality chemical indicators, meteorological and level observations are available real-time estimate time-varying recharge, which act as a surrogate identify periods rapid that indicate susceptibility. Estimating recharge using methods, such base-flow recession, unsaturated models, water-table fluctuations (WTF), cannot capitalize on currently technologies telecommunication infrastructure conduct estimation at scales relevant characterizing infiltration. We present linear, physics-based state-space (SS) model one-dimensional includes preferential diffuse-flow water table. The take advantage data for altitude, precipitation, evapotranspiration. Model parameters calibrated over an observation period, Kalman Filter (KF) is subsequently applied continuously update observed (water-table altitude) unobserved (groundwater recharge) system states predict future new become available. SS/KF algorithm demonstrated Masser Groundwater Recharge Site Pennsylvania, USA comparisons made with estimates WTF methods. results frequency (daily vs. sub-daily) dictates allocation between diffuse flow. Additionally, because processes encompass many nonlinearities, estimated need be updated least seasonally account changing conditions.