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• Board Meeting Date: 3/18/2008
• Description: ISF Section - Injury with Mitigation - Case No. 3-99CW34 - Application of Charles Nearburg
• Board Meetings - Doc Type: Memo

In addition to being filled via the above-described direct flow diversions from Trout Creek, the
Channels also most likely will intercept ground water tributary to Trout Creek. Such ground
water will provide a necessary source of water for fish habitat during the winter (October 16 to
April 30). Depletions associated with evaporation and secondary evapotranspiration from the
Channels are estimated to total between 2.6 and 4.1 acre-feet annually. Under the injury with
mitigation proposal, such depletions will be deemed to occur as the result of surface water
diversions from Trout Creek, given the summertime diversions of surface water from the Creek
and the negligible lag in groundwater depletions to the Creek in the winter.
Benefits of mitigation
At the January Board meeting, Steve Belz of Black Creek Hyrdrology gave a presentation on the
benefits to the natural environment resulting from Mr. Nearburg's stream restoration and habitat
improvement projects. In general, in the unrestored reach of Trout Creek, only one of the
CWCB hydraulic criteria was satisfied at flow rates of both 35 c.f.s. and 15 c.f.s., (the decreed
summer and winter instream flow rates. In the restored section of Trout Creek, all three criteria
were satisfied at a flow rate of 25 c.f.s., and two out of three criteria were satisfied at a flow rate
of 15 c.f.s. These findings are significant because, under the injury with mitigation proposal,
diversions of 1 c.f.s. into the Channels will occur only when the gaged flow in Trout Creek is
above 25 c.f.s. (3 of 3 criteria satisfied). When gaged flows drop below 25 c.f.s., then maximum
diversions into the Channels will be limited to 0.5 c.f.s., and diversions will cease entirely when
the gaged flow in Trout Creek is below 15.1 c.£s (2 of 3 criteria satisfied). Further, the benefits
to the natural environment extend to over 8,500 linear feet of Trout Creek, while the limited
impacts from diversions into the Channels will affect approximately 2,700 feet of the ISF reach -
providingmore than 3 feet of improved stream for every 1 foot of potentially impacted ISF
reach.
Alternatives
The purpose of the Channels is to create additional fishery habitat and deep water refuge on
Trout Creek, as a component of the overall habitat improvement and stream restoration work
performed by Mr. Nearburg on Trout Creek. Mr. Nearburg has explored the following
alternatives to the injury with mitigation proposal described herein:
i. Mr. Nearburg evaluated the possibility of developing or purchasing storage above the
point of diversion for the Channels to augment any diversions into the Channels.
However, the reaches of Trout Creek not far above Mr. Nearburg's property are located
on Federal lands, making the development of new storage structures unlikely. One
ii. storage structure, Rankin Reservoir, does exist upstream of the Channels; however, Mr.
Nearburg is not the owner of this structure.
iii. Mr. Nearburg considered the creation of mitigation habitat on reaches of Trout Creek
outside of his Trout Creek Ranch property; however, access and other issues made this
option infeasible. The on-site mitigation that is the basis for this proposal provides more
direct benefits to the affected ISF water right.
Colorado Division of Wildlife Evaluation of Proposal
CWCB and Colorado Division of Wildlife ("CDOW") staff members have visited the site and
have met with Charles Nearburg's representatives to discuss this proposal. Based upon the
substantial amount of stream habitat improvements completed, the documented increase in fish
biomass, and Mr. Nearburg's agreements to reduce historical diversions through the Caster
Ditch and to confer with the CDOW concerning best management practices regarding the Trout