OPTIMAL ESTIMATION OF SPATIALLY-VARIABLE RECHARGE AND TRANSMISSIVITY FIELDS UNDER STEADY-STATE GROUNDWATER-FLOW .2. CASE-STUDY

The first-order analytical solution of the inverse problem for estimat ing spatially variable recharge and transmissivity under steady-state groundwater flow, developed in Part 1 is applied to the Upper Floridan Aquifer in NE Florida. Parameters characterizing the statistical stru cture of the log-transmissivity and head fields are estimated from 152 measurements of transmissivity and 146 measurements of hydraulic head available in the study region. Optimal estimates of the recharge, tra nsmissivity and head fields are produced throughout the study region b y conditioning on the nearest 10 available transmissivity measurements and the nearest 10 available head measurements. Head observations are shown to provide valuable information for estimating both the transmi ssivity and the recharge fields. Accurate numerical groundwater model predictions of the aquifer flow system are obtained using the optimal transmissivity and recharge fields as input parameters, and the optima l head field to define boundary conditions. For this case study, both the transmissivity field and the uncertainty of the transmissivity fie ld prediction are poorly estimated, when the effects of random recharg e are neglected.