MODEL DEVELOPMENT FOR CONJUNCTIVE USE STUDY OF THE SAN JACINTO BASIN, CALIFORNIA¹

Abstract

A two-layered confined-unconfined numerical model for flow and mass transport is developed for the San Jacinto Basin. The model structure is determined by the geological structure of the Basin and model parameters are calibrated using 20 years of historical records. The total number of historical head observations used for the flow model calibration is 1,117 and the total number of the estimated parameters is 91. The two-layered transport model is also calibrated using historical water quality records. Sensitivity analysis of the flow model shows that only 68 parameters (out of a total of 91) are relatively sensitive and reliable. However, the unreliable parameters (23 of them) are found to be insensitive and thus not significant to the prediction and management of conjunctive use of surface water and ground water. The developed flow model has been used to study the two proposed artificial recharge scenarios for the San Jacinto Basin. We have found that during a relatively dry condition, an artificial recharge rate of 80 acre-ft/day can be achieved during the recharge period October through January.However, for a relatively wet condition, only 80 percent of the proposed rate can be effectively stored in the Basin during these months.(KEY TERMS: artificial recharge; conjunctive use; mathematical models; model calibration; sensitivity analysis.) at the lowest possible long-term cost.

Evaluation of aquifer heterogeneity effects on river flow loss using a transition probability framework

“…These effects are especially important in the arid southwest United States where management and accounting of surface water flows are important for meeting state water demands and interstate compact agreements. Many modeling studies that include river‐aquifer interactions have been focused on questions of regional‐scale water management and use [ Onta et al , 1991; Reichard , 1995; Wang et al , 1995; Konrad , 2006]. For such efforts, the motivation to understand river‐aquifer interaction is municipal planning and water balance [ Fleckenstein et al , 2004], but many models rely on what may be interpreted as an oversimplification of the heterogeneity within the study area.…”

River‐Aquifer Interactions, Geologic Heterogeneity, and Low‐Flow Management

“…Traditionally, modeling studies that include riveraquifer interactions have been focused on questions of regional-scale water management and conjunctive use (Onta et al 1991;Reichard 1995;Wang et al 1995). In this context, interaction between the aquifer and rivers is motivated mainly by interest in the regional water balance.…”

Groundwater flow modelling of Yamuna-Krishni interstream, a part of central Ganga Plain Uttar Pradesh

“…Interactions between an alluvial aquifer system and river are influenced by the spatial arrangement of hydrofacies at the interface between the river and the underlying aquifer (Woessner 2000). Modelling studies that include river-aquifer interactions need to be focused on the impacts of regional scale, water management and conjunctive use issues (Onta et al 1991;Reichard 1995; Wang et al 1995). For instance, the accuracy of groundwater inflow or outflow estimates, made from the difference in river flows at the beginning and the end of a reach, is limited because flow differences are often small compared to the total river flow (Rushton 2006).…”