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
infiltrated water makes its way back to a surface
water stream and is then diverted by downstream
water users.
River -
Figure 8-1 is a schematic of the return flows from Qiversiorr
agricultural water use. Under water law, ~.
appropriators have a legal right to rely on the
continuation of stream conditions in effect when they Can~~ ~
made the appropriation, including return flows to the S~~pag~~
ir I
stream from diversions made by other appropriators.
The result of this pattern of water use is that water in
Colorado can be diverted and used and then
subsequently rediverted and used many times, as
return flows from one irrigator's use of water form the
supply for a downstream user's water right. Other
benefits of these return flows include the recharge of
aquifers. Many domestic and irrigation wells would
dry up if groundwater recharge from historical
irrigation practices were not maintained. Return flows
can also result in improved riparian habitat and more
even stream flows, which help maintain year-round
fisheries that would otherwise not exist. Thus, for
example, many of the small urban creeks that flow
through urban areas support riparian habitat and aquatic
species as a result of return flows from lawn irrigation
and other urban water uses.
8.2.1 Conservation
^elayed Groundwater Returns
Surface Water Returns~
Dom~st~c $~
Ifflge~tlOf1 ~~I~S
Crap Cansumption
and Evaporation
Figure 8-1
Return Flaws from Agricultural Use of Surface Water
conservation effort. In addition, the table indicates an
estimated percent reduction in total M&I demand that
might result from each level of conservation; and a
generalized cost of the water savings at each level. Such
generalized savings and costs may vary with the
program implementation conditions of each water
provider. The percent savings and generalized costs of
each level of water conservation effort are described in
detail in Appendix E(SWSI Water Demand Forecast
Report).
8.2.1.1 Municipal and Industrial Water
Conservation
M&I water conservation programs result in improved
water use efficiency. M&I water savings occur through
the modification of water-using fixtures (e.g., showers,
landscapes, cooling towers) and behaviors (e.g.,
showering time, irrigation schedules, maintenance
schedules, etc.). The effects of conservation on M&I
water demand are the result of both passive and active
water conservation efforts. These conservation efforts,
though somewhat unpredictable in their rate of success
since they require changes in consumer behavior, can be
effective means of reducing water supply needs, with
little cost to the community.
Table 8-1 summarizes five levels of water conservation
developed during SWSI. Each level shows examples of
water conservation programs that a utility or water
provider might implement at the given level of
~~
^ Lev~l 1 iNat~r Can~eru~tian Savings: This level is
defined as water savings that result from the impacts
of plumbing codes, ordinances, and standards that
improve the efficiency of water use. These
conservation savings are sometimes termed
"passive" savings because water utilities do not
actively fund and implement the programs that
produce these savings. These savings occur as new
construction and remodeled buildings become more
water efficient over time. In addition, landscaping
ordinances contribute to these passive savings.
Level 1 conservation is included in the SWSI baseline
water demand forecast.
In contrast, water conservation savings resulting from
utility-sponsored water conservation programs are
referred to as "active" savings. The options included as
potential future options for SWSI in terms of M&I
conservation, correspond to the different levels of active
conservation (Level 2 through 5) are described below.
~~
Sfvtewide Woter Supoly Initiofive
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