2008-06-24_HYDROLOGY - M1979191

• Permit No: M1979191
• IBM Index Class Name: HYDROLOGY
• Doc Date: 6/24/2008
• Doc Name: Wate supply plan
• From: DWR
• To: Applegate Group, Inc.
• Media Type: D
• Archive: No

Mr. Richard Raines June 17, 2008
Middle Poudre Combined Plan - Lafarge West, Inc. Page 7 of 9
9. By July 1, 2008, the Applicant is required to provide updated accounting to document
the monthly amount and timing of releases to maintain the historical return flow
obligations of the Gray Lakes water used for replacement purposes. Applicant is also
required to provide a copy of a revised lease for Gray Lakes water that reflects the use of
a 45% consumptive use credit and that corresponds to the required replacement amount
to be shown on the revised Table 1.
10. The applicant was advised in the previous plan that if a subsequent request to use Gray
Lakes water for replacement purposes is submitted without a detailed historical
consumptive use analysis being provided to substantiate a larger credit, the consumptive
use credit allowed will be limited to 45% for the Gray Lakes water (55% assumed to be
return flow). Since a detailed historical consumptive use analysis of the Gray Lakes water
was not provided, the consumptive use credit allowed for this plan will be limited to
45% for the Gray Lakes water (55% assumed to be return flow).
11. The Applicant shall perform an inspection and provide verification for all parcels of dried
up land used to generate augmentation credits during the term of this SWSP. 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 the entire irrigation season for each parcel of land
used in this SWSP. The Applicant shall provide all affidavit(s) to the division engineer by
November 15, 2008 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. The Applicant shall modify accounting to reflect that the credit from any
dried-up fields containing alfalfa or native grass was 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 %-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.
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%
1. Adapted from EVAPOTRANSPIRATION AND AGRONOMIC RESPONSES IN FORMERLY
IRRIGATED MOUNTAIN MEADOWS, South Park, Colorado, March 1, 1990; Revised September 1, 1991