Simulation and analysis of conjunctive use with MODFLOW's farm process.

Area of Science:

• Hydrology and Water Resource Management
• Environmental Modeling
• Agricultural Water Use

Background:

• Traditional groundwater models like MODFLOW often lack integrated landscape and agricultural water use components.
• Accurate analysis of conjunctive water use requires simulating interactions between surface water, groundwater, and land surface processes.
• Existing models struggle to capture the dynamic interplay of water supply and demand in agricultural regions.

Purpose of the Study:

• To introduce and demonstrate the utility of the Farm Process (MF-FMP) extension for MODFLOW.
• To enable fully coupled simulation of water movement and use across the hydrologic system, including natural and agricultural vegetation.
• To enhance the analysis and management of conjunctive water resource systems.

Main Methods:

• Extension of MODFLOW with the Farm Process (MF-FMP) to integrate landscape water dynamics.
• Development of distributed, cell-by-cell, supply-constrained and demand-driven components within 'water-balance subregions'.
• Application of MF-FMP to simulate micro-agriculture in Pajaro Valley and macro-agriculture in the Central Valley.

Main Results:

• MF-FMP successfully simulates coupled surface water, groundwater, and land-surface water balances.
• Case studies demonstrated the analysis of aquifer storage and recovery, water distribution systems, and climate variation impacts.
• The model effectively captures the importance of precipitation, surface water, and groundwater in different hydrologic settings for conjunctive use.

Conclusions:

• MF-FMP provides a powerful tool for simulating natural and anthropogenic components of the hydrologic cycle.
• The model facilitates a comprehensive understanding and improved management of water supply and demand dynamics.
• Integrated simulation of landscape processes is crucial for accurate conjunctive water resource analysis.