2018-04-13_HYDROLOGY - M1977436

• Permit No: M1977436
• IBM Index Class Name: Hydrology
• Doc Date: 4/13/2018
• Doc Name Note: Combined Replacement Plan
• Doc Name: Combined Replacement Plan
• From: DNR Water Resources
• To: DRMS
• Email Name: JLE
• Media Type: D
• Archive: No

Aggregate Industries South Platte Combined SWSP April 13, 2018
Plan IDs 3614, 4773, 3624, 4772, 4616, 3437, 3376, 3650, 3668, and 5475 Page 4 of 20

Distel Pit
(St. Vrain River) Status: Mining operations at the Distel Pit were completed in 2011 and
reclamation is in progress. In 2017, Aggregate used water from the Distel
site as a water supply for a portable ready-mixed plant located at the
site for a short-term job. Depletions covered by this SWSP include water
used for lagged depletions from dust control, past concrete batching and
past aggregate production, and post-pumping depletions from past
dewatering. Dewatering at the site ceased due to flooding in September
2013, and Aggregate currently has no plans to reactivate dewatering.
The City of Longmont has assumed the augmentation responsibilities for
lagged and future depletions from evaporation and consumptive use by
wetlands vegetation at the site under their plan for augmentation
decreed in case no. 2009CW271.
Exposed Ground Water Surface: N/A (augmented under case no.
2009CW271)
Active Dewatering: No
Tull Pit
(St. Vrain River) Status: Mining operations are anticipated to continue at the Tull Pit in
2018. Depletions covered by this SWSP include water lost due to
evaporation, dust control, aggregate production, and dewatering. The
site will be dewatered continuously throughout 2018.
Exposed Ground Water Surface: 1.0 acre
Active Dewatering: YES
W.W. Farms Pit
(Lower Poudre River) Status: Mining operations at the W.W. Farms Pit (aka Riverview
Resources) are expected to continue to be on hold for this plan period.
Depletions covered by this SWSP include water lost due to evaporation,
dewatering, dust control, and concrete batching. During Spring of 2011
the pit was flooded by the Poudre River due to the high spring runoff
conditions. Ongoing dewatering has reduced the exposed surface area at
the site. The entire remaining exposed surface area will be assessed
evaporative losses as this is an unlined pit. The site will be dewatered
continuously throughout 2018. Note: The Applicant has obtained a
decreed plan for augmentation in water court case no. 1990CW23 to
cover evaporation from up to 66 acres of exposed water surface area in
one or more unlined ponds remaining at the site post mining; however,
since final reclamation of the site has not yet occurred, all depletions
from this pit will continue to be replaced under this SWSP during this plan
period.
Exposed Ground Water Surface: 36.0 acres
Active Dewatering: YES
F-Street Pit
(Lower Poudre River) Status: Mining operations at the F-Street Pit are complete and
reclamation is in progress. Depletions covered by this SWSP are limited
to water lost due to evaporation, as lagged dewatering and operational
depletions are no longer accruing to the river.
Exposed Ground Water Surface: 26.2 acres
Active Dewatering: No