USE AND EFFECTIVENESS OF MUNICIPAL WATER RESTRICTIONS DURING DROUGHT IN COLORADO
<br />for reservoir management but is also useful to com-
<br />pare the efficacy of demand management strategies to
<br />other means of reducing drought vulnerability, such
<br />as through constructing new projects, purchasing new
<br />water rights (or options on rights), constructing
<br />wastewater reuse systems, and so on. For these types
<br />of comparisons, water volumes are much more rele-
<br />vant than percent reductions in customer demands.
<br />Only for this reason are volumetric savings presented
<br />in this study.
<br />Table 4 provides estimated ranges of actual and
<br />potential water savings in acre feet (equal to 325,851
<br />gallons) using the net use and expected use per capita
<br />methods as upper and lower boundaries. The volume
<br />of water saved is a function of total water deliveries
<br />(i.e., the size of the water system), the percent savings
<br />achieved through restrictions, and the type and dura-
<br />tion of restrictions. Collectively, the eight providers
<br />studied saved approximately 18,263 to 36,000 acre
<br />feet of water during the four -month study period. To
<br />put these values into perspective, 20,000 acre feet is
<br />the typical annual water demand of a town of approxi-
<br />mately 75,000 people (using the conservative assump-
<br />tion of 0.27 acre feet per person) and has a retail (end
<br />user) value of more than $13 million (assuming a typ-
<br />ical rate of $2 per thousand gallons).
<br />The potential savings could have been much
<br />greater. Rough extrapolations suggest that had our
<br />seven providers with mandatory restrictions utilized
<br />their programs for the entire four -month study peri-
<br />od, total savings likely would have ranged from
<br />32,491 to 48,998 acre feet. Furthermore, if all eight
<br />providers had used the twice a week watering sched-
<br />ule and achieved the 30 percent average level of sav-
<br />ings seen for this approach in this study, water
<br />savings could have totaled 64,483 to 76,784 acre feet.
<br />Using the same logic, the more aggressive once a
<br />week schedule could have potentially translated into
<br />113,920 to 130,301 acre feet of savings had this
<br />approach been used in mandatory programs over the
<br />four -month period.
<br />Translating Drought Savings to Long Term
<br />Conservation Potential. These potential savings
<br />estimates provided above are admittedly very rough
<br />and should be used judiciously; nonetheless, they sug-
<br />gest a potential for demand management in the
<br />region that is perhaps not confined merely to drought
<br />emergencies. In the absence of drought, the cities of
<br />Colorado's Front Range may want to consider adopt-
<br />ing outdoor watering restrictions on a permanent
<br />basis as part of a long term conservation program.
<br />This is already done in Castle Rock (just south of
<br />Denver), which has utilized the every third day
<br />watering schedule since 1996.
<br />There are several reasons, however, to use caution
<br />in assuming that demand management savings dur-
<br />ing drought could be sustained during nondrought
<br />periods. Specifically, the savings experienced were
<br />largely the result of cooperation and "goodwill" on the
<br />part of citizens and represented a "belt tightening"
<br />that was publicly acceptable given the emergency con -
<br />ditions but perhaps unacceptable if adopted as a nor-
<br />mal part of management. Additionally, to the extent
<br />that some water savings were, in part, due to man-
<br />agement decisions to postpone system flushing and
<br />maintenance, to limit water applications on public
<br />parks, and other emergency drought coping measures,
<br />it would be dangerous to assume that these savings
<br />could be achieved on a permanent basis.
<br />It should also be noted that any effort to reduce
<br />waste in the system could have the effect of reducing
<br />the "drought cushion" that allows cities the flexibility
<br />of drought year conservation savings although that
<br />cushion could likely be provided in other ways, such
<br />as through an expanded use of dry year options with
<br />the agricultural sector (Nichols et al., 2001; Luecke et
<br />al., 2003). This threat becomes real if the water con-
<br />served goes to support new growth rather than being
<br />held in reserve for drought emergencies. The relation-
<br />ship between water management and growth is
<br />beyond the scope of this paper as well as beyond the
<br />control of water managers, but it is nonetheless part
<br />of the context that must be considered when describ-
<br />ing the relationship between drought coping and long
<br />term conservation. In any case, further research is
<br />warranted regarding the ability to translate drought
<br />savings into permanent conservation savings.
<br />SUMMARY AND RECOMMENDATIONS
<br />This study indicates that outdoor watering restric-
<br />tions, particularly mandatory programs, are an effec-
<br />tive means of reducing water demand during drought
<br />periods among Colorado's Front Range municipalities.
<br />While this conclusion is evident regardless of the
<br />means used to calculate savings, the expected use per
<br />capita methodology yields the greatest savings and is
<br />a particularly useful approach for measuring the
<br />effectiveness of water restrictions from the standpoint
<br />of the end users (i.e., residents) dealing first -hand
<br />with the impacts of drought on residential landscap-
<br />ing.
<br />As expected, the level of water savings increases as
<br />the frequency of permitted watering days declines
<br />and as time limits (per zone) are tightened. The dra-
<br />matic jump in savings achieved by cities using the
<br />twice a week regime compared to the marginally more
<br />JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION 85 JAWRA
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