2015-03-02_HYDROLOGY - M1996060

• Permit No: M1996060
• IBM Index Class Name: HYDROLOGY
• Doc Date: 3/2/2015
• Doc Name: Substitute Water Supply Plan
• From: DNR Division of Water Resources
• To: DRMS
• Email Name: ECS
• Media Type: D
• Archive: No

Poudre Pits Combined SWSP
February 26, 2015
Page 2 of 9
portion of the site and all depletions from the Firestein and Tigges parcels will be covered under this
SWSP.
The La Poudre site consists of three separate cells designated as the West Lake, Middle Lake,
and East Lake. Some additional aggregate has been discovered below the West Lake and is proposed
to be mined during this plan period.
Depletions
Evaporation and Operational Losses
During this SWSP period, depletions will consist of evaporation losses and production depletions
at the Firestein /Tigges, La Poudre, and North La Poudre Pits. The depletions for each site are shown in
the following table:
Table B - 2015 Site Depletions (acre - feet)*
`Depletions shown do not include those from past or projected dewatering operations at the sites.
For the purposes of this SWSP, depletions are assumed to impact the Cache la Poudre River
perpendicular to the point of depletions, which is considered to be the centroid of the exposed
surface area at each site. Evaporative depletions for each site were calculated using a gross annual
evaporation of 38.5 inches, with a credit of 9.78 inches for effective precipitation (based on an
average annual precipitation of 13.97 inches for the'Windsor weather station).
Operational losses at the Firestein /Tigges site will consist of 0.96 acre -feet of water for dust
control. Depletions from the Firestein /Tigges site will impact the Cache la Poudre River upstream of
the Greeley No. 3 Ditch (WDID 0300934).
Operational losses at the La Poudre and North La Poudre sites will consist of 2.20 acre -feet of
water for dust control, 12.50 acre -feet of water lost with 425,000 tons of aggregate, and 15.58 acre -
feet of water for the production of 125,000 cubic yards of concrete (assumes 40 gallons of water per
cubic yard of concrete). The aggregate is mined below the water table and is washed; therefore the
water retained in the mined product is considered to be 4.0% of the mined material by weight.
Water for dust control and concrete batching purposes will be pumped from the West Lake in the La
Poudre site. Depletions from the La Poudre and North La Poudre Pits will impact the Cache la
Poudre River upstream of the Whitney Irrigation Ditch (WDID 0300930).
The Alluvial Water Accounting System (AWAS), which uses the Glover method, was used to
determine the lagged depletions to the Cache La Poudre River from past (since 1990) and projected
evaporation and operational losses at each site. The following parameters were used in the model
with the alluvial aquifer boundary condition: the distance (X) from the centroid of the exposed
Evaporation
Water Lost
Water Consumed
Dust
Total
Totat Lagged
Site Name
Losses
in Mined
in Concrete
Control
Depletions
Depletions
Product
Batching
Firestein /Tigges
108.91
0
0
0.96
109.87
114.29
La Poudre
42.75
12.50
15.58
2.20
102.67
93.81
North La Poudre
29.64
Total
181.30'
12.50
15.58
3.16
212.54
208.10
`Depletions shown do not include those from past or projected dewatering operations at the sites.
For the purposes of this SWSP, depletions are assumed to impact the Cache la Poudre River
perpendicular to the point of depletions, which is considered to be the centroid of the exposed
surface area at each site. Evaporative depletions for each site were calculated using a gross annual
evaporation of 38.5 inches, with a credit of 9.78 inches for effective precipitation (based on an
average annual precipitation of 13.97 inches for the'Windsor weather station).
Operational losses at the Firestein /Tigges site will consist of 0.96 acre -feet of water for dust
control. Depletions from the Firestein /Tigges site will impact the Cache la Poudre River upstream of
the Greeley No. 3 Ditch (WDID 0300934).
Operational losses at the La Poudre and North La Poudre sites will consist of 2.20 acre -feet of
water for dust control, 12.50 acre -feet of water lost with 425,000 tons of aggregate, and 15.58 acre -
feet of water for the production of 125,000 cubic yards of concrete (assumes 40 gallons of water per
cubic yard of concrete). The aggregate is mined below the water table and is washed; therefore the
water retained in the mined product is considered to be 4.0% of the mined material by weight.
Water for dust control and concrete batching purposes will be pumped from the West Lake in the La
Poudre site. Depletions from the La Poudre and North La Poudre Pits will impact the Cache la
Poudre River upstream of the Whitney Irrigation Ditch (WDID 0300930).
The Alluvial Water Accounting System (AWAS), which uses the Glover method, was used to
determine the lagged depletions to the Cache La Poudre River from past (since 1990) and projected
evaporation and operational losses at each site. The following parameters were used in the model
with the alluvial aquifer boundary condition: the distance (X) from the centroid of the exposed