Important observations and parameters for a salt water intrusion model

Area of Science:

• Hydrogeology
• Environmental Engineering
• Coastal Processes

Background:

• Saltwater intrusion into coastal aquifers is a significant environmental challenge.
• Traditional intuitive analysis often falls short in calibrating complex ground water flow models.

Purpose of the Study:

• To demonstrate the utility of sensitivity analysis in understanding saltwater intrusion calibration.
• To identify optimal data types and locations for calibrating density-dependent ground water flow models.

Main Methods:

• Utilized a density-dependent ground water flow simulator.
• Conducted five experimental simulations to test parameter sensitivity.
• Analyzed the impact of dispersivity on hydraulic head, salinity, and flow distributions.

Main Results:

• Dispersivity is a critical parameter for reproducing steady-state conditions in the freshwater-saltwater transition zone.
• Optimal observation points for hydraulic head and salinity are at the 'toe' of the transition zone.
• Submarine ground water discharge zones are ideal for flow observations, with salinity data being more effective than head data.
• Parameter correlation can hinder unique estimation of hydraulic conductivity and recharge, but additional flow observations can mitigate this.

Conclusions:

• Sensitivity analysis provides superior insight into saltwater intrusion calibration compared to intuitive methods.
• Strategic placement of hydraulic head, salinity, and flow observations is vital for accurate model calibration.
• Findings are applicable to complex coastal aquifer systems and inform model development practices.