2018-09-05_HYDROLOGY - M1996049

• Permit No: M1996049
• IBM Index Class Name: HYDROLOGY
• Doc Date: 9/5/2018
• Doc Name Note: Renewal Request
• Doc Name: Stormwater Management Plan ‎(SWMP)‎
• From: Permittee
• To: DRMS
• Email Name: ECS
• Media Type: D
• Archive: No

monthly average temperature and precipitation values calculated for MCR.
Table 1
Average Values of Temperature and Precipitation Calculated for Maryland Creek Ranch
Mean Monthly Temperatures at Mean Monthly
Mean Monthly Weather Stations(°F) Temperature Temperatures at
Month Precipitation at Lapse Rate MCR(°F)
MCR(inches) Green Mtn Dam Dillon 1E(elev. (°F/1,000 ft)
(elev. 7,740 ft) 9,060 ft) (elev. 8,850 ft)
Jan 1.1 16.5 15.1 -1.06 15.6
Feb 12 20.0 17.6 -1.82 18.5
Mar 1.4 28.3 234 -3.71 25.3
Apr 1.6 38.4 326 -4.39 34.8
May 1 4 47.9 420 -4.47 443
Jun 1 1 56.3 501 -4.70 52.5
Jul 1.9 61.9 55.8 -4.62 58.2
Aug 1.8 60.1 54.3 -4.39 565
Sep 1 3 529 47.5 -4 09 496
Oct 1 1 42.7 37.7 -3 79 396
Nov 1.0 29.4 25.5 -2 95 27.0
Dec 1.1 19.4 17.0 -1 82 179
Annual 16.0
2.2 PROJECT DEPLETIONS
Under Permit No. M-1996-049, the DRMS has approved a total of 6 mining cells (gravel pits) within MCR.
Of these, Everist has finished mining operations in cells Nos. 1, 2, and 3 and is currently mining Cell No. 4
(Figure A-3 shows the location of the mining cells). For 2017 and 2018, Everist plans to excavate around
350,000 tons per year and anticipate producing 65,000 cubic yards (CY) of concrete and 150,000 tons of
asphalt annually.The annual water consumption associated with the MCR aggregate operation is estimated
at 98.6 acre-feet(AF)for the 2017-2018 period. Table B-1, attached, summarizes, on a monthly basis, the
2017 and 2018 estimated water depletions. The methodologies utilized to calculate these water depletions
are outlined in the following paragraphs
2.2.1 Evaporative Losses
Cell No. 1 is utilized as a tailing pond and is considered backfilled. The Cell 2 pond has a surface area of
5.1 acres which will not change during 2017 and 2018. The Cell 3 pond currently measures 18.5 acres and
is close to its final configuration, although the area of exposed groundwater may decrease as sloping and
backfilling operations in this cell continue. Calculation of evaporative depletions within the context of this
SWSP renewal request, assumed that the water surface area in Cell 3 will remain unchanged during 2017
and 2018. Mining is currently taking place in Cell 4, where the surface area of exposed groundwater is
approximately 13.1 acres. However, Everist plans on dewatering this pit during the March through
November production season; thus during this time period, the acreage of groundwater exposed in Cell 4
will be negligible. Groundwater pumped from Ce114 would be discharged into the adjacent Cell 3 pond.
2 MURESOURCE