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To: Lanya Ross, Anneka LaBelle, Ali Elhassan From: Evan Christianson, Ray Wuolo Subject: Metro Pumping Optimization 3 Date: April 2, 2015 Page: 5 Lakes are considered to have a wide littoral zone if they are less than five feet deep over more than 20 percent of the total surface area. These lakes have a greater potential of being negatively impacted by reductions in stage. For these lakes (68 in the seven county metropolitan area), the water flux out was not allowed to increase more than 10 percent and/or the groundwater flux into these lakes was not allowed to decrease more than 10 percent. All remaining River Package boundary cells that were not included in groups described above were grouped based on the public land survey township they are located in (Figure 1). This resulted in an additional 103 constraints. For these grouped boundary cells, the total groundwater flux in was not allowed to be reduced by more than 15 percent and/or total water flux out was not allowed to increase more than 15 percent. Grouping these River Package cells, rather than imposing constraints on individual cells or surface water features, was necessary to help keep the total number of constraints to a manageable level to maintain reasonable solution times for the optimization algorithm. 2.2.3 Flow Direction Constraints Flow direction constraints for Optimizations 1, 2, and 3 are identical and were included for areas of existing groundwater contamination provided by the Metropolitan Council. The flow direction in the vicinity of these contamination areas was not allowed to deviate from the baseline condition by more than 10 degrees. The baseline condition used was the flow direction simulated with the steady-state version of Metro Model 3. 2.3 Substitution of MMProc GWM-VI uses a stand-alone executable, MMProc.exe, to write MODFLOW input files, execute MODFLOW, and extract head and cell -by -cell flow values from MODFLOW output files. MMProc.exe is hardwired to only read output from a small number of MODFLOW packages. Two major limitations of MMProc.exe necessitated the development of a separate and much more flexible pre- and post -processor: inability to read/write data for the River Package, and implementation of groundwater flow -direction constraints. Pre- and post -processing for Optimization 2 and Optimization 3 are identical. Pre- and post -processing Optimization 1 involved less constraints associated with River Package boundary cells. Description of the pre- and post -processing steps described in the technical memo from August 14, 2014 and is repeated below for completeness. A python script, pyMMProc.py, was developed to handle the capabilities of MMProc.exe while being more flexible and allowing use of the River Package and flow -direction constraints. A comparison of how MMProc.exe and pyMMProc.py interact with GWM-VI and MODFLOW is shown on Figure 2a and Figure 2b.