2025-04-14_HYDROLOGY - M1977436

• Permit No: M1977436
• IBM Index Class Name: Hydrology
• Doc Date: 4/14/2025
• Doc Name: Substitute Water Supply Plan
• From: Division of Water Resources
• To: DRMS
• Email Name: NCG
• Email Name: JLE
• Media Type: D
• Archive: No

Holcim South Platte Combined SWSP April 14, 2025
Plan IDs 3614, 4773, 3624, 4772, 4616, 3437, 3376, 3650, 3668, 5475, 5829, Ft 6243 Page 6 of 37
Wattenberg Status: Resource extraction at the Wattenberg Pit is complete and
Pit reclamation is in progress. Depletions covered by this SWSP include water
lost due to evaporation, and dewatering. Prior to 2018, the north pit was
(South Platte dewatered with water delivered to the nearby Broda Pond. The north cell
Mainstem) has since been lined, and dewatering operations have shifted to the south
cell with water to be discharged to multiple locations. A portion of the
water will be pumped to the Stillwater Ski Lake located south of the pit
to mitigate lower levels in the pond due to the suppressed water table
resulting from dewatering. A portion of the water may be pumped to a
new recharge pond on the west side of the site in order to mitigate low
water table levels in domestic wells in the area. A portion of the water
may be discharged to the Huett Seep, a surface drainage adjacent to the
site. The remainder of the dewatering discharge will be pumped across
the South Platte River to the Broda Pond located within the Platte Valley
Pit. Once water enters the Broda Pond, some is pumped to the river to
ensure the pond does not spill. There was a temporary cessation of
dewatering in January 2018. The site will be dewatered continuously
throughout 2025. A new well permit must be obtained before the
surface area of this pit can exceed 25 acres.
Exposed Groundwater Surface: 37.0 acres
Active Dewatering: Yes
Platte Valley Status: Mining operations at the Platte Valley Pit are not anticipated to
Pit occur in 2025, though reclamation activity consisting of backfilling
portions of the site will continue in 2025. Holcim intends to import
(South Platte 1,354,800 tons of material mined at other sites to the Platte Valley Pit
Mainstem) site for processing. The imported material will be washed with water
withdrawn from exposed groundwater ponds on the site, therefore 2% of
the weight of the imported material will be charged as a depletion. The
initial moisture content of the material will be charged as depletions at
the originating source, which may include sources operated by other
entities. Depletions covered by this SWSP include water lost due to
evaporation, aggregate processing, dust control, and concrete batching.
Water for concrete batching will come from Well Permit No. 13410-F-R
(WDID 0207073). Note that the water right for this well was on the
division engineer's 2010 Decennial Abandonment List, but the well may
still be used in accordance with its permit as long as all depletions are
treated as junior to all other vested water rights in accordance with this
SWSP and the well complies with the South Platte Well Measurement