Simulating ground water-lake interactions: approaches and insights.

Area of Science:

• Hydrogeology
• Environmental Modeling
• Water Resource Management

Background:

• Modeling lake-ground water interactions is crucial for understanding hydrological systems.
• Early methods used fixed lake stages, limiting accuracy.
• Advanced packages like MODFLOW's LAK package offer improved simulation capabilities.

Purpose of the Study:

• To evaluate and compare different approaches for modeling lake-ground water interactions.
• To provide guidelines for constructing accurate and efficient lake-ground water models.
• To assess the impact of grid size on simulation results.

Main Methods:

• Comparison of MODFLOW's LAK package with analytic element lake simulation.
• Grid sensitivity analyses to evaluate the influence of grid resolution.
• Development of guidelines for model grid size, flow location, and vertical capture.

Main Results:

• MODFLOW's LAK package provides superior output compared to fixed lake stage methods.
• Analytic element models show acceptable agreement with MODFLOW, with discrepancies related to model setup.
• Large grid sizes can lead to significant discrepancies in simulated lake-ground water flux.

Conclusions:

• Guidelines for model construction, including grid size, are essential for accurate lake-ground water interaction simulations.
• Selecting the appropriate lake simulation tool is critical for reliable results.
• Reducing grid size in finite-difference models improves agreement with analytic element methods.