2012-03-30_HYDROLOGY - M1979191

• Permit No: M1979191
• IBM Index Class Name: HYDROLOGY
• Doc Date: 3/30/2012
• Doc Name: CSWSP
• From: OSE
• To: Applegate Group, Inc.
• Permit Index Doc Type: Hydrology Report
• Email Name: ECS
• Media Type: D
• Archive: No

Mr. Jared Dains
Lafarge Middle Poudre Combined SWSP
March 29, 2012
Page 4
(344.3 acres), and are applying 5 of those shares for recharge credits under this plan. The dry -up
acreage claimed for Lafarge's 5.5 shares would be 305.6 acres of the 344.3 historically irrigated acres
on the Three Bells property. The historical consumptive use credit of the 5.5 BEDC shares associated
with the Three Bells property was determined to be 281.4 acre -feet, based on a historical consumptive
use analysis that was completed in support of an application for an augmentation plan pending in case
no. 2002CW205.
Table 2 shows the average ditch diversion for the Box Elder Ditch from 1950 to 2007. Table 3
takes the average ditch diversions for the Box Elder Ditch from 1950 to 1984 and analyses the historic
consumptive use and return flows for Lafarge's Three Bells Farms 5.5 shares. Table 4 breaks this
information down further to come up with the historic farm headgate diversions and return flows for the 5
BEDC shares to be used in this plan. As shown on Table 4, the average farm headgate diversions
associated with the subject 5 BEDC shares is 457.0 acre -feet and the associated return flow obligations
will total 201.1 acre -feet. This leaves a net consumptive use credit of 255.9 acre -feet, or 51.2 acre -feet
per share. Lafarge is projecting to deliver the average headgate diversion 457.0 acre -feet into recharge
for 2012. Accordingly, the monthly timing of 457.0 acre -feet (full farm headgate delivery of the 5 shares)
was used in the recharge model to determine the recharge accretion credits for 2012. The recharge
model uses the following parameters: transmissivity (T)= 45,000 gallons /day /foot, the distance of centroid
of the recharge pit to the Cache La Poudre River (X) =1,600 feet, the distance for the parallel
impermeable boundary to the Cache La Poudre River (W) =5,000 feet, and the specific yield (S) =0.2.
The lagged accretions to the Cache la Poudre River are estimated to total 528.84 acre -feet for this
approval period (includes carry over from recharge in previous years). Actual recharge credits and
return flow obligations will be based on the actual deliveries made for replacement purposes in this
SWSP.
As shown on Table 6, recharge credits from the 5 BEDC shares are not sufficient in March - July,
and again in November - December of 2012. These deficient months will be covered through leases
with LCRC and PRPA. Leases from LCRC dated March 6, 2012 for 65 acre -feet and November 29,
2011 for 9 acre -feet of fully consumable water will make replacements for depletions not covered by the
recharge program from March 2012 through July 2012. Copies of the LCRC leases are attached to this
letter. The source of the replacement water will be from Gray Lakes, which can deliver water to Box
Elder Creek and from there to the Cache La Poudre River. A 0.25 percent per stream mile transit loss
will be assessed on releases from the Gray Lakes. The water storage right for the Gray Lakes owned by
LCRC is not presently decreed for augmentation, therefore a change of use application for the Gray
Lakes water storage right was filed with the Division 1 Water Court in case no. 2006CW276. A detailed
historical consumptive use analysis was performed by TZA Water Engineers, Inc. (`TZA ") in support for
case no. 2006CW276. According to the analysis LCRC water rights have historically been used to
provide supplemental water to irrigated lands within the Lake Canal Service area. Based upon the crop
mix, irrigated acreage and water available for irrigation, TZA concluded that the Lake Canal system is
water short. TZA also noted that a historical consumptive use of 65% is not uncommon for the use of
supplemental reservoir water within water short ditch systems. For the purposes of this plan, the
consumptive use associated with the Gray Lakes water was assumed to be 45 %. This also means 55%
of the delivered water constituted historical return flows, which must be maintained. Therefore, in
addition to the water to be released for replacement purposes, an additional release representing the
transit loss and return flow component shall be released from Gray Lakes to maintain the historical
return flow regime.
A lease from PRPA dated November 18, 2001 and amended on February 29, 2012 for a total of
9.5 acre -feet will make replacements for depletions not covered by the recharge program in November
and December 2012. A copy of the PRPA lease is attached to this letter. The source of the