S8_11-15-04

• Basin: Statewide
• Title: SWSI Phase 1 Report - Section 8 Options for Meeting Future Water Needs
• Date: 11/15/2004
• Author: CWCB
• SWSI - Doc Type: Final Report

Section 8
Options for Meeting Future Water Needs
additional agricultural water rights will be needed to
ensure adequate supply during below normal runoff
conditions.
^ New reservoirs provide flat water recreation
opportunities. Boating, swimming, and lake fishing
opportunities are increased.
^ Storage often provides consistent flows below the
storage facility that can provide ideal cold water
fishery habitat. Many of the Gold Medal fisheries in
Colorado are below storage facilities.
^ There is the potential for hydropower generation.
The potential issues and conflicts in developing new
storage projects include:
^ There may be environmental impacts to the aquatic
and terrestrial environment. These impacts are likely
to be more significant than those resulting from
enlarging existing storage facilities.
^ Loss of recreation associated with free-flowing
streams, such as fishing, rafting, and kayaking.
^ Water quality impacts can be associated with
impounded water.
^ Cultural impacts associated with inundation of lands.
^ Permitting and mitigation can be more expensive and
lengthy than other water supply options and have an
uncertain outcome.
^ A significant amount of storage may be required to
produce an acre-foot of firm yield. The amount of
storage required will be basin and water rights
specific.
8.2.3.2 Expansion of Existing Storage Facilities
The expansion of existing storage facilities can be a cost-
effective means to develop additional storage. Options
for increasing storage in existing facilities include raising
dam embankments, dredging of sediments, and
deepening reservoirs and raising spillway levels.
The expansion of existing storage facilities has several
benefits including:
^ There are likely to be less environmental and
recreational issues than for new storage, since the
reservoir already exists.
^ Permitting and mitigation requirements may be less
difficult than for construction of a new storage facility
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^ Existing water rights are not affected if the water is to
be stored under a new water right.
^ The expansion of storage to capture unappropriated
water can potentially reduce the pressure to transfer
water from existing uses (i.e., agricultural water) to
meet future water needs.
^ The expansion of storage for unappropriated water
captures an unused resource.
^ The expansion of storage helps to maximize compact
entitlements for beneficial use within the State of
Colorado.
^ Overall system efficiencies are increased by
minimizing system spills.
^ The yields of exchanges and non-potable reuse for
irrigation are increased. Maximizing the reuse of
consumable return flows requires storage, since
return flows occur year-round, but the demand for
irrigation is seasonal.
^ Storage is required to firm the yield of transfers of
agricultural water rights. If additional storage is not
constructed, additional agricultural water rights will be
needed to ensure adequate supply during below
normal runoff conditions.
The potential issues and conflicts in expanding existing
reservoirs include:
^ Environmental and recreation impacts can also occur
here depending on the size of facility.
^ Expanding existing storage facilities does not diversify
water sources and the risks of structural failures or
water quality catastrophes are not reduced.
^ Permitting and mitigation, though typically less difficult
than that for new storage, can still be expensive and
lengthy with an uncertain outcome.
^ A significant amount of storage may be required to
produce an acre-foot of firm yield. The amount of
storage required will be basin and water rights
specific.
^ There are a limited number of reservoirs that can be
enlarged. Many reservoirs are not cost-effective to
enlarge.
^ There is a limited volume of increased storage
available through reservoir enlargements.
^ The enlargement of existing reservoirs may not be
cheaper than new storage. The original dam
embankments and spillways, in many instances, were
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Sfvtewide Woter Supoly Initiofive
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