2014-04-23_REVISION - M2000041

• Permit No: M2000041
• IBM Index Class Name: Revision
• Doc Date: 4/23/2014
• Doc Name: Comments
• From: John Sliman
• To: DRMS
• Email Name: TC1
• Media Type: D
• Archive: No

Ms. Heidi Frey
June 14, 2013
Page 2
discharge, or to Southwest Sod for irrigation, or both. A totalizing flow meter on the irrigation
delivery pipeline will measure the flow rate and record the volume of water being delivered for
irrigation use. Any dewatering water not used for irrigation will be discharged to the Arkansas
River using the existing Evans #2 Pit dewatering discharge system.
Irrigation Depletions
For purposes of this 2013 SWSP amendment, the water pumped through the irrigation delivery
pipeline will be considered a 100 percent depletion to the Arkansas River. Thus, there will be no
need to estimate and account for evaporation from the forebay pond in the Excelsior Ditch or to
determine lagged irrigation return flows from the irrigated fields. Fremont reserves the right to
propose future accounting in order to claim the unconsumed irrigation return flows as an offset
to the stream depletions caused by use of the dewatering system pumping for irrigation. The
Evans #2 SWSP accounting forms have been revised to include the lagged stream depletions
attributable to dewatering system deliveries to irrigation (see attached).
Since the source of water is groundwater generated throughout the Evans #2 Pit via the
dewatering system, the lagged stream depletions will be determined using the same lagging
parameters and lagging model as are currently in use for the gravel pit (x = 2,400 ft, w = 5,000 ft,
T = 100,000 gpd/ft, S = 0.20 ft/ft).
Based on the lagging parameters for the Evans #2 Pit described above, the following unit
response function (URF) illustrates the pattern of stream depletions that would accrue to the
Arkansas River from each month of pumping.
Evans #2 Pit Dewatering System Unit Response Function
Month
1
1 2
1 3 1
4
1 5
1 6
7
8
9
10
11
12
Year 1
9.8%
1 23.1%
13.8%
1 10.0%
1 7.9%
1 6.4%
5.3%
4.3%
3.5%
2.9%
2.4%
1.9%
Year 2
1.6%
1 1.3%
1.1%
1 0.9%
1 0.7%
1 0.6%
0.5%
0.4%
0.3%
0.3%
0.2%
0.2%
Year
0.1%
1 0.1%
0.1%
1 0.1%
1 0.1%
1 0.1%
-
By way of example only, and based on an assumption that half of the projected allocated July
through October 2013 and March 2014 irrigation demand of Southwest Sod Farms is provided
by the Evans #2 Pit dewatering system (72 ac -ft total), the following tables show the amounts of
pumping and stream depletion replacement requirements (72 ac -ft total) that would result.
2013 Dewatering Supply to Irrigation at 50% of Projected Demand