2013-03-12_HYDROLOGY - M1977439

• Permit No: M1977439
• IBM Index Class Name: HYDROLOGY
• Doc Date: 3/12/2013
• Doc Name: SUBSTITUTE WATER SUPPLY PLAN
• From: DWR
• To: DRMS
• Email Name: ECS
• Media Type: D
• Archive: No

Site Name
Evaporation
Losses
(ac -ft)
Lost in
Product
(ac -ft)
Dust
Control
(ac -ft)
Total
(ac -ft)
Total
Lagged
Stream
Depletions
(ac -ft)
Home Office Pit
32.40
0.00
25.90
58.30
58.64
Overland Ponds
Site
5.83
12.83
25.90
44.55
46.93
North Taft Hill
Expansion Site
7.53
0.00
0.00
7.53
7.55
Total
45.76
12.83
51.80
110.38
113.12
Mr. Heintz and Ms. Wynne
Upper Poudre Combined SWSP
March 12, 2013
Page 2
M- 2011 -049. Ground water evaporation at the Triber Ponds and Lamb Ponds are replaced
through the Partners SWSP (WDID 0302556) and are therefore not included in this SWSP.
Although the Lamb Pond's depletions are being replaced by the Partners SWSP, they are within
MMM's DRMS mining permit for the Home Office Pit and thus final reclamation liability remains
with MMM as they are the Home Office Pit permit holder.
For the Overland Ponds Site the exposed area has significantly changed due to the lining of
cell 1 (liner approved October 5, 2011) and the near completion of cell 2's liner. Until the cell 2
liner is approved, all water exposure within the lined perimeter must be treated as ground water
with evaporation losses assessed. The current exposed ground water acreage at the Overland
Ponds Site is 2.3 acres and this is expected to increase to 3.1 acres in August due to the planned
creation of dewatering trenches associated with new mining in cell 4. For the North Taft Hill
Expansion Site, there are two ponds of 2.45 acres and 1.2 acres that are exposing ground water.
See Figure 1 for the location and boundaries of the subject mining sites.
Depletions
During the term of this plan, the only consumptive use at the Home Office Pit is the
evaporation of exposed ground water and water pumped for dust control. The consumptive use at
the Overland Ponds Site will be from water lost with mined product, from dust control, and from
evaporation of exposed ground water. The North Taft Hill Expansion Site consumptive use will only
be from evaporation of exposed ground water. The total losses for the sites are shown in the
following table:
TABLE B - DEPLETIONS
The estimate of evaporative losses under this combined plan was reduced during the ice
covered period. You have assumed the ice covered period occurs from December through
February, based on the average temperatures of 29 °F for December, 27 °F for January and 31 °F
for February; taken from the Fort Collins weather station (053005) using available data through
2005. The ice covered periods may be used to reduce the amount of evaporative losses that need
to be replaced; however, for the purpose of this SWSP, the Applicant shall replace the net
evaporation depletions from the exposed ground water surface area that may occur during the
assumed ice covered period (December through February) for any time that the pits are not
completely covered by ice. Computation of the net evaporation during any time that the pits are not
completely covered by ice shall be determined as the pro -rata amount of the monthly gross
evaporation rate distribution amount identified in the State Engineer's General Guidelines for