2015-09-30_PERMIT FILE - M1985112

• Permit No: M1985112
• IBM Index Class Name: PERMIT FILE
• Doc Date: 9/30/2015
• Doc Name: Application AM01
• From: Loloff Construction
• To: DRMS
• Type & Sequence: AM1
• Email Name: PSH
• Email Name: WHE
• Media Type: D
• Archive: No

Mr. J.C. York
July 13, 2015 Page 2
Table 1 — Wells within area of Influence of Proposed Slurry Wall
Well Data from Wells Within Area of Influence
Model Results
Name
Pemit
Well
Depth
Rate (gpm)
Reported
Depth to
Water (ft)
Saturated
Thickness
(ft)
Max. Change
in Water
Levels (ft)
Future Depth
to Water (ft)
Future
Saturated
Thickness (ft)
%Change
in Sat.
Thick (ft)
DOWNGRADIENT WELLS
VARRA
75865 F NO
ND
ND
NO
ND
ND
ND
NO
DAVIS FARMS
14960 R 101
1150
31
70
-1
32
69
-1%
BAAB A C
620 Al45
800
9
36
-1
10
35
-3%
TAYLOR JAMES
223885
44
10
11
33
-1
ND
ND
ND
UPGRADIENT WELLS
TRUJILLO
23312
25
10
5
20
1
4
21
5%
ORONA
28174
19
20
8
11
1
7
12
9%
PALMA
297435
ND
ND
NO
ND
1
Uncertain
Uncertain
Uncertain
HARRELL ELDON
226878
50
15
16
34
2
14
36
6%
ROTHE
259513
27
20
2
25
1
1
26
4%
TRUYELLO
2947 F 21
400
6
15
1
5
16
7%
HARRELL BRIAN
287278
30
50
ND
ND
2
Uncertain
Uncertain
Uncertain
DILKA
44539
34
25
3
31
1
2
32
3%
VANBEBER
25941
25
50
2
23
1
1
24
4%
WADSWORTH
19472 F ND
105
ND
NO
1
Uncertain
Uncertain
Uncertain
VANBEBER
16038
25
24
4
21
1
3
22
5%
Three down gradient wells can be expected to experience a decline in water levels of
approximately 1 foot. Since well yield is proportional to the saturated thickness, we would
expect less than a 5% decrease in the maximum theoretical pumping rate of those wells. We do
not believe this is a significant impact.
Based on our modeling, eleven up gradient wells can be expected to have 0.5 to 2 foot increases
in water levels. Only one of those wells (Harrell Eldon) has a reported pre -mining water level
depth exceeding 10 feet. The rest of the wells either have reported depths to water of less than
10 feet or no recorded level so the depth remains "uncertain." If the recorded well locations and
depth to water are correct relative to the pit and if the wells are located near vulnerable structures
(homes with basements or excavations), those structures could be vulnerable to rising
groundwater resulting from the slurry wall.
Uncertainty
Whether future flooding or water logging will occur depend on numerous factors including: 1)
well location relative to the pit and slurry wall; 2) the location and depth of vulnerable structures
such as homes with basements; 3) the location, magnitude and timing of well pumping and
recharge from precipitation, agriculture, and canal seepage that could also affect water levels;
and 4) the location of existing drainage or canals that may intercept rising groundwater.
Therefore, there is considerable uncertainty whether there is a real and quantifiable risk of
significant impact.
Mitigation
Potential mitigation includes: 1) installing a drain around the slurry wall to minimize any
mounding or shadow effect to keep the aquifer at equilibrium 2) or moving or abandoning