2012-12-07_HYDROLOGY - M1994005

• Permit No: M1994005
• IBM Index Class Name: HYDROLOGY
• Doc Date: 12/7/2012
• Doc Name: SWSP
• From: OSE
• To: Wright Water Engineers, Inc.
• Permit Index Doc Type: Hydrology Report
• Email Name: DMC
• Media Type: D
• Archive: No

Depth to Ground
Water (Feet)
Percent Reduction in CU Credit'
Native Grass
Alfalfa
1
85%
100%
2
50%
90%
3
30%
75%
4
20%
50%
5
15%
35%
6
10%
20%
7
5%
15%
8
0%
10%
Mr. Peter Foster December 6, 2012
Colona Gravel Pit, Substitute Water Supply Plan Page 5 of 7
division engineer.
11. The Applicant has agreed to dedicate the historical consumptive credit from irrigation of
the site with 1 share of the Ouray Ditch to long -term replacement requirements in the
unforeseen event, or events, which would lead to the abandonment of the pit. Note that
such dedication does not relieve the Applicant from the requirement to obtain a water
court approved plan for augmentation to replace depletions to the stream system in time,
place and amount. Notwithstanding this dedication, in the event that mining operations
cease absent a water court approved plan for augmentation, the pit must be backfilled to
at least two feet above the highest recorded ground water table elevation at the pit.
12. The Applicant will inspect all parcels of dried up land used to generate augmentation
credits during the irrigation season to verify dry-up. The final verification of dry up will be
in the form of an affidavit signed by an individual having personal knowledge of the dry
up for this year's entire irrigation season for each parcel of land used in this SWSP. All
affidavits must be provided to the division engineer by the expiration date of this SWSP
(September 30, 2013) in order that the final determination of augmentation credits for
the irrigation season can be made along with mapping showing any revisions to the dry
up acreage. Credit from any dry-up fields containing alfalfa or native grass will be
assessed in the following manner:
(a) For fields deep tilled or chemically treated to successfully kill alfalfa or native grass,
100% credit will be given for consumptive use as otherwise computed under the
conditions of this approval.
(b) For fields not deep tilled or chemically treated to successfully kill alfalfa, records of
monthly monitoring of depth to groundwater at existing irrigation wells or existing or new
monitoring wells or piezometers within %4 -mile of each alfalfa or native grass field must
be maintained. Credits will be reduced according to the following table when depth to
groundwater is less than the depth assumed to provide no significant contribution to
alfalfa growth. Measurements taken at the start of each month will determine the
necessary reduction in credit to be applied during the following month. The Applicant
may use another methodology upon review and approval by the state engineer and •
division engineer.
1 Adapted from EVAPOTRANSPIRATION AND AGRONOMIC RESPONSES IN FORMERLY IRRIGATED MOUNTAIN MEADOWS,
South Park, Colorado, March 1, 1990; Revised September 1, 1991