BOARD02036

• Board Meeting Date: 9/24/2001
• Description: CF Section - Investments - South Platte River Decision Support System Year 2
• Board Meetings - Doc Type: Memo

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Agenda item
September 24-25, 2001 meeting
Page 7 of15

monitoring wells will be constructed, providing needed information on the geologic
structure and aquifer properties of the groundwater basins, The surface and groundwater
planning tools will be expanded to enable water users, the CWCB and DWR to address
present and future water policy, development and administration issues in a timely,
efficient and cost effective manner,

. Alternative 3 is the "full-featured alternative" that provides water users, the CWCB and
DWR a DSS that collects data and develops tools for administration and planning at a
detailed, but expensive, level. Alternative 3 includes everything from Alternative 1 as
well as Alternative 2, plus additional data collection and components, The additional data
collection includes augmentation plans, substitute supply plans, transfer decree data,
installation of additional stream gages and additional monitoring wells, Alternative 3
would produce an SPDSS that would meet nearly all of the expressed needs of the water
users as well as all of SB 96-74 recommendations applicable to the SPDSS,

RECOMMENDATIONS

The CWCB and DWR management team and the consultant team consider Alternative 2 to be
the most cost-effective alternative that: (1) satisfies the DSS needs as specified by the CWCB
and DWR to aid in addressing the current and future water resources issues before them, (2)
addresses the expressed needs of water users as determined during the needs assessment
interviews, (3) provides a level of data collection necessary to provide the information needed by
the DSS applications, and (4) is consistent with the DSS developments completed or under
development in other parts of the State,

In general, the data and components for each alternative are inter-dependent. Each alternative
identifies and anticipates the modeling and tool needs for the SPDSS so that a data collection
program can be developed and implemented during the first two years of SPDSS development.
The components identified for each alternative require that a certain level of data collection
activities be carried out to meet the needs of that alternative, If Alternative 1 were initially
selected and then a later decision were made to implement Alternative 2, additional data
collection tasks would be needed, with resultant increases in time and costs due to the loss of
economies of scale, This delay would potentially prohibit the CWCB and DWR from addressing
water resource issues in a timely and effective way, For example, Alternative 1 includes only the
expansion of the existing SB 96-74 Denver Basin MODFLOW model to include the overlying
alluvium, If Alternative I was initially selected and three years later it was decided that a
MODFLOW model for the Lower South Platte Alluvium region was required, three years of
needed data collection for this new effort would have been lost. It would then be necessary to
design a new data collection program at a higher cost and longer time frame than if Alternative 2
had been selected initially, keeping the CWCB and DWR from making potential policy decisions
on using the best available data and tools,

Consequently, the consultant team and the State management team recommend Alternative 2 for
implementation, By providing the data and analysis tools outlined in Alternative 2, the SPDSS