2011-10-17_HYDROLOGY - M1980136

• Permit No: M1980136
• IBM Index Class Name: HYDROLOGY
• Doc Date: 10/17/2011
• Doc Name: SWSP
• From: OSE
• To: Applegate Group, Inc.
• Permit Index Doc Type: Hydrology Report
• Media Type: D
• Archive: No

Eagle Pit SWSP
October 5, 2011
Replacements
Page 3 of 8
In consolidated Case Nos. 81CW94 and 81CW291, a change in use and change in point of
diversion for 0.30 cfs of the Neilson South Ditch was decreed. During the historical irrigation
season of the Neilson South Ditch (decreed as May 22 through October 27), the Applicant may
divert at the C -1 Well no more than 17.2 acre - feet/year from its 0.30 cfs of the Neilson South Ditch
for industrial purposes. Diversions under this change shall occur at a flow rate of 0.30 cfs or less
and shall take place only when said 0.30 cfs of the Neilson South Ditch is in priority and physically
available at the ditch's decreed point of diversion on the right bank of Brush Creek. To the extent
that the Applicant diverts the 0.30 cfs of Neilson South Ditch at the C -1 Well, an equal amount of
diversions shall be curtailed at the ditch headgate.
The corresponding depletions estimated to occur during the historical irrigation season are
9.3 acre -feet. Depletions occurring during the historical irrigation season are to be replaced using
the consumptive use credit from the dry -up of historically irrigated lands under the Neilson South
Ditch. Pursuant to consolidated Case Nos. 81 CW94 and 81 CW291, a total of 6 acres of
historically irrigated lands will be dried up, resulting in a consumptive use credit of 9.6 acre -feet
(based on a consumptive use credit of 1.6 acre -feet per acre,of dry -up). The decree indicates the
proposed gravel pit operation will remove 10 or more acres of irrigated pasture, therefore the
decree indicates the 6 acres of land dried up for credit does not need to be specifically designated.
In addition to diverting the changed 0.30 cfs of the Neilson South Ditch at the C -1 Well, the
well may also divert under the groundwater right also decreed in consolidated Case Nos. 81 CW94
and 81CW291 for industrial use. Pursuant to paragraph 6 of the Judgment and Decree, diversions
under the groundwater right for the C -1 Well are limited to 5.4 acre - feet /year at a maximum rate of
0.56 cfs.
In order to replace the additional depletions proposed to occur under this SWSP, the
Applicant will dry-up an additional 44 acres of land historically irrigated under the Neilson South
Ditch. Pursuant to consolidated Case Nos. 81 CW94 and 81 CW291, 72 acres were historically
irrigated at the Eagle Pit. Lafarge will claim 44 acres of dry-up for this SWSP. The decree in
consolidated Case Nos. 81CW94 and 81CW291 determined the historical consumptive use of the
Neilson South Ditch at the Chambers Ranch to be 1.6 acre -feet per year per acre of irrigated
pasture. Thus, the additional dry-up of 44 acres will yield 70.4 acre -feet of historical consumptive
use credits to replace mining depletions. The 70.4 acre-feet from 44 acres of dry-up credit will
replace depletions during the irrigation season as shown on the attached Table 2. As a result of
the mining operation, the historically irrigated lands are reportedly already dried -up as shown on
the attached Figure 1.
The decree in consolidated Case Nos. 81CW94 and 81CW291 did not provide a detail of
the monthly timing of the historical consumptive use credit; therefore, the monthly timing of the
credit from this ditch was estimated using a more recent decree for Lafarge's nearby site known as
the Gypsum Ranch Pit. The decree for the Gypsum Ranch Pit was approved in Case No.
2002CW211.