9344

• UCREFRP Catalog Number: 9344
• Author: Camp Dresser & McKee Inc.
• Title: Replacement of the Plateau Creek Pipeline.
• USFW Year: 1996.
• USFW - Doc Type: Denver.
• Copyright Material: NO

1
3.3.3.1 Historic Section 7 Consultations and Hydrologic Groupings
The USFWS provided background information on previous Section 7 consultations within the
Colorado River Basin tributary to the 15-mile reach. This information included average annual
\ depletion values for 65 project entries which total approximately 322,000 ac-ft/yr, some of which
pre-date the Recovery Implementation Program (RIP). The pre-RIP projects include a number of
well known lazge depletion reservoir storage and oil shale development projects. Both the pre- and
post-RIP projects were divided into 5 distinct hydrologic groups for the purpose of distributing the
annual depletions on a monthly basis. These hydrologic groups were determined in consultation
with the USFWS hydrologist as follows:
^ ^ Reservoir Projects
^ Municipal & Industrial (M&I)
^ Ski Areas
^ Oil Shale Projects
^ Ponds
Table 3.8 is a detailed i tin of the ro' ver e ual de letions rovided b the USFWS
i s g p ~ ects and a ag ann p p y ,
divided into the specific hydrologic groupings with total depletions by hydrologic category. The
majority of the depletion total is attributed to several pre-RIP Section 7 consultations associated with
reservoir storage and oil shale projects.
With the exception of M&I and ponds, the other hydrologic groups were further subdivided into
subcategories to account for monthly distribution differences among specific projects based on
information provided by the USFWS. Annual depletion totals were then allocated into monthly
distributions using average monthly percentages on a project specific basis. Individual projects
having the greatest impact on the overall baseline adjustment (reservoirs and oil shale) exhibited
differences in their respective monthly distribution percentages. The detail breakdown by individual
project and subcategory is included in Attachment B for reference:
3.3.3.2 Calculation of Total Average Annual Monthly Distributions
Project-specific and subgroup monthly distributions were totaled and then aggregated to each of the
5 hydrologic groups to obtain monthly total Section 7 reductions by group. The group totals were
then summed to obtain total monthly Section 7 baseline reductions for each month of an average
r year. The average yeaz is defined as one of average hydrologic response.
The resulting reductions were converted from ac-ft to cfs. The resulting calculation of monthly
reductions as a percentage of the average annual total of 445 cfs (322,000 ac-ft) indicated that for
all months except May, June, and July, the monthly Section 7 reduction distributions range from 3
to 4'/Z percent of the annual total depletion. In May and June the percentage is 20.30 and 31.49,
respectively and the July figure drops to 13.44 percent. This is reflective of conditions associated
with reservoir storage projects and oil shale projects which have storage considerations. Thus,
approximately 65 percent of the annual Section 7 reduction affects the Colorado River during the
three month period of May through July.
CDM Camp Dresser & McKee B-12
0:8047-IIO~DOCIAPPEND-B.DOC