2022-08-25_PERMIT FILE - M2022001

• Permit No: M2022001
• IBM Index Class Name: Permit File
• Doc Date: 8/25/2022
• Doc Name: Adequacy Review Response #2
• From: Civil Resources, LLC
• To: DRMS
• Email Name: JLE
• Email Name: PSH
• Media Type: D
• Archive: No

6.3.2 Drain Recharge
In order to keep groundwater from being exposed to evaporation and to help mitigate the shadow affect to the north a
series of model iterations were run utilizing the Drain DRT MODFLOW Package. The Drain DRT package allows for the
water removed from the drain cells to be recharged back into selected cells rather than removed from the model. The
conceptual model was set to simulate recharge to an open bottom manhole placed between Cells 3 and 7 at the north of
the model along with perforated pipe extending three (3)cells to the east and west.The majority of the recharge was
placed in the manhole with the perforated pipe acting as shallow overflow mitigation. As shown in Table 7, piping the
diverted water to the north of the Site will reduce the shadow affect on the wells to the north (Schmidt, United and Owens
Wells)as well as reducing evaporation.
Table 7 details three options for drain mitigation. Option 1 was modeled as the construction of all slurry walls at the Site
and the water from the drain/wells was routed to the river by surface structures. For Option 2, slurry wall 5S was not
constructed and the water was routed to the river by surface structures. Option 3 adds recharge north of the Site to
Option 2. Option 3 is shown on Figures 7 and 7A.
Table 7
Groundwater Surface Elevations with Drain Install 0 tions
Option 2
Option 1 Drain
Drain Option 1 Mitigation Option 2 Option 3 Option 3
Mitigation Difference (No Cell-5S Difference From Drain Mitigation Difference From
Location Baseline All SW From Baseline SW) Baseline With Recharge Baseline
Patrid a House 4736.5 47346 -1.90 47359 -0.6 47359 -0.6
Cline House 47371 47350 -2 10 47362 -0 9 47363 -0 8
Harding House 47369 4734.7 -2 20 4735.7 -1 2 4735.8 -1 1
Wiedeman House
13434 4738.4 4738 1 -0.30 47387 03 47388 04
Wiedman House 13218 47386 4740.2 160 47407 2 1 47408 22
Shape House 47385 47400 150 47405 20 47405 20
HS Land and Cattle 4732.7 47319 -0.80 47327 00 47328 01
Karbowski Brave
House 47257 47232 -2.50 47242 -1 5 47245 -1.2
Schmidt Well 47146 47102 440 4710.9 -3 7 4712.8 -1.8
United Well 47123 47065 -5 80 47063 -6 0 47106 -1 7
Owens Well 47147 47115 -3 20 47115 -3 2 47124 -2 3
Wright House 47180 47119 -6 07 47116 -6 4 47130 49
Schmidt House 47192 4716.0 -3 20 47161 -3 1 4716.7 -2 5
Smit House 47196 47173 -2 30 47178 -1 8 47183 -1 3
Kissler House 47302 47296 -0.60 47306 0.4 47307 05
Woolverton House 47314 47310 -0 40 47320 06 47320 06
Shimon House 47336 47329 -0 70 4734.1 05 4734.2 06
Kern House 4734.4 47334 -1 00 47346 02 47346 02
Rainbolt House 47364 4734.9 -1 50 47360 -0 4 47361 -0.3
Gilcrest Valley HS 1 47378 47371 -0 70 47377 -0 1 47377 -0 10
Groundwater Model Report—Section 20 Gravel Mine Site -11 - August 2022