International Irrigation Center
Computer models are developed for computing optimal perennial groundwater withdrawal strategies for the East Shore Area of Utah's Great Salt Lake. The underlying aquifer has three confined or unconfined layers. Both embedding and response matrix (RM) approaches are tested and compared. Historically, it has been difficult to incorporate simulation of an unconfined aquifer and many external flow equations described by nonsmooth functions within linear programming models. RM models normally assume system linearity. The presented RM model overcomes this difficulty using cycling and influence coefficients generated with a modified MODFLOW model. In this groundwater flow simulation model, the above nonlinear terms are treated linearly. The embedding model contains quasi-three- dimensional finite-difference forms of the groundwater flow equation as constraints. To achieve a stable optimal solution, the completely linearized formulation is cyclically optimized. The embedding model is preferred here because of its flexibility and ability to handle more linear and nonlinear hydrological variables for a specified amount of memory. Using the embedding model, optimal, spatially distributed, sustainable, annual groundwater pumping rates are computed for alternative future scenarios. Strategy results are then verified using external steady-state and transient simulation. This study demonstrates utility of the embedding approach for optimizing perennial-yield planning of large, complex aquifers.
Takahashi, S. and R.C. Peralta. 1992. Optimal perennial groundwater yield planning for the East Shore Area, Utah. International Irrigation Center Report IIC-92/3. Utah State Univ., Logan, Utah. 81 p.