BOARD00707

• Board Meeting Date: 7/23/2001
• Description: ISF Section - Town of Basalt De Minimis Finding, Case No. 5-00CW252
• Board Meetings - Doc Type: Memo

.

e

e

e

I. The State Engineer Office's Analytical Stream Depletion Model used to
perform these analyses is sensitive to changes in pumping rate; therefore, the
delayed well depletion factors are distributed differently with an increase or a
decrease in the pumping rate. The increased diversions during June and July
increased the depletion factors for these two months (when Basalt has upstream
augmentation water available to it), but decreased the depletion factors for the
remaining months, especially during November and April, when Basalt's
augmentation plan is not capable of providing replacement water.

2. The increased depletions due to increased pumping rate during June and July
were offset by available consumptive use credit during the same months.

Applicant's consulting engineer believes that Basalt's monthly diversions will not
substantially change even though there will be periods when Well No. 13 may be pumped
at a rate of 404 gpm during June and July. As in Case No. 90CW138, the Town of Basalt
will provide adequate replacement water to augment the depletions to instream flow water
rights on the Frying Pan River and Roaring Fork River downstream of the confluence with
the Frying Pan River.

Staff Recommendation
The Staff recommends that the CWCB:

I) Find that the Town's change in operations is still de minimis to the Roaring
Fork River upstream of the confluence of the Frying Pan River and the Roaring
Fork River; and,
2) Enter the maximum potential depletion values in the de minimis database,
despite the Applicant's claims that it will rarely pump 404 gpm. That value is
for 3.63 aflyr for the Roaring Fork River, assuming Well No. 13 will be
pumped at a constant rate of 404 gpm during the entire months of June and
July.

5.00cw252 town of basalt deminimis request board memo