2012-06-07_HYDROLOGY - M2001005

• Permit No: M2001005
• IBM Index Class Name: HYDROLOGY
• Doc Date: 6/7/2012
• Doc Name: Transit Mix Concrete Co Pit, Approval Period
• From: DWR
• Media Type: D
• Archive: No

Ms. Julia Keedy Page 2
June 6, 2012
pumped for dust suppression. The area of exposed ground water from February 1, 2011 — July 31,
2011 is projected to be 19.37 acres (consisting of a 15.62 acre pond in Phase 1, a 1.25 acre fresh
water supply pond in Phase 2, and a 2.5 acre pond in Phase 2 that only exists when mining ceases
and the dewatering pump is shut off). The area of exposed ground water from August 1, 2011 —
January 31, 2013 is projected to increase to 25.07 acres to account for the maximum projected
increase in the Phase 2 exposed ground water once mining ceases again. The depletions of this
operation for the 2012 plan year (February 1, 2012 — January 31, 2013) consist of 76.08 acre -feet
of evaporative loss from the exposed ground water, 7.65 acre -feet of water removed via 260,000
tons of mined product (4% loss by weight), and 5.0 acre -feet pumped for dust suppression. A
monthly breakdown of these amounts for both plan years is given in Table 1, attached. Total
depletions from mining activities are estimated to be 78.31 acre -feet for the 2011 plan year and
88.74 acre -feet for the 2012 plan year.
REPLACEMENTS
The main source of replacement water is based on the 45.4 acres that is now removed from
agricultural production by the mining operation out of the total pro rata share of 89.47 acres of
alfalfa and silage corn historically irrigated with Lester- Attebery Ditch water. A ditch wide analysis
has been completed and the calculated historic consumptive use for the Grisenti parcel was about
221 acre -feet per year (2.47 acre -feet per acre). The historic irrigation summary is attached as
Table 2. The 45.4 acres provide an annual stream depletion credit of 112.17 acre -feet (123.59
acre -feet credit during April through October and a return flow obligation of 11.42 acre -feet during
winter months). 60 shares of Twin Lakes Reservoir water will cover the replacement water for the
winter months. As of November 1, 2010, Transit Mix has 61.63 acre -feet in their Twin Lakes
account, which is subject to a 7.81 percent transit loss (0.07% per mile for 111.6 miles) for delivery
to the Grisenti site. The proposed replacement schedule for this plan's approval period is provided
in the attached Table 3.
POST PLAN DEPLETIONS
Should the dewatering of the Phase 2 pit cease, Transit Mix shall dedicate the 60 shares of
Twin Lakes Reservoir water to this plan. These shares along with the historical consumptive use
credit will provide adequate replacement water to cover 35 acres of potentially exposed ground
water.
CONDITIONS OF APPROVAL
The state and division engineers have reviewed the plan and the adequacy of each source
of water provided for use as augmentation water, including, where necessary, the historical
consumptive use of each water right, and return flows from diversion of waters imported into the
Arkansas River Basin or other fully consumable waters proposed for use as augmentation water.
In accordance with C.R.S. § 25 -8- 202(7) and Senate Bill 89 -181 Rules and Regulations adopted
on February 4, 1992, the state engineer has determined that subject to the terms and conditions
below, the replacement supply is of a quality to meet the requirements of use to senior
appropriators.
This substitute water supply plan is hereby approved pursuant to C.R.S. § 37 -90- 137(11),
subject to the following conditions:
1. This current plan shall be valid through January 31, 2013, unless otherwise revoked or
modified.