NRC Approves Water Conservation Plan Designed Demand by at least 20% over 7 years

By Alan Pryor

Davis Historical Per Capita Water Use and Future Targets

One cannot directly compare total per capita usage by some cities with that of Davis because many cities (e.g. West Sacramento) have a far greater percentage of industrial vs home users. That said, Davis has roughly equivalent use patterns seen in other local cities for single-family homes and multi-family apartments (which doesn’t include UC obviously)

Davisites used an average of about 200 gallons per capita per day (gpcd) from about 1990 to 2007. Over the past 5 years, though, consumption in Davis has steadily dropped each year to about 155 gpcd in 2011.

This recent downward trend mirrors use reductions throughout California. The reductions result from a combination of conscious efforts by citizens to conserve and reduce water use, lower use by new residential developments which lower overall average use in a community, the impact of the recession causing consumers to watch their utility budgets more carefully, and cooler than average summer weather for the past several years which resulted in decreased landscape irrigation needs.

The NRC is wary of entirely relying on recent water use patterns influenced by the recession that will certainly some day end and by unseasonably cool weather which likely will return to more normal, hotter weather patterns in the future. Thus, the NRC is assuming a “true” average baseline use of 167 gpcd to predict average usage in the City, without additional conservation efforts, in better economic times and when normal summer weather patterns invariably return.

Background and Basis for the Proposal

The NRC’s Water Management Subcommittee has been working on developing recommendations to achieve an additional 20% reduction in water demands below the state water use target established in the 2010 Urban Water Management Plan adopted by the Davis City Council. The impetus for these efforts are that the NRC was tasked by the Council with proposing an additional 20% water conservation goal and developing a plan to achieve the lower water use target by 2020.

Final recommendations to implement a potable water demand reduction plan to reduce average usage to 134 gpcd by 2020 were presented to and approved by the NRC at their June 25 meeting. These recommendations will be forwarded to the Council and the Water Advisory Commission by the Dept of Public Works for their analysis and consideration.

In planning the strategies to be employed in this conservation program, the NRC considered that all recommendations must meet the following key water savings criteria

1. Cost-effective

2. Reliable over time

3. Voluntary vs. Mandatory Approach

4. Achievable by 2020

5. Least impact on community lifestyle

6. Forward thinking – considering changes in technology and regulations

Four Recommended Changes to Reduce Potable Water Consumption

With these criteria guiding the thinking and debate, there were 4 broad recommendations approved by the NRC as outlined below.

1. Indoor Fixture Retrofit – The City plans to continue a rebate incentive program to encourage all citizens to convert to low flow toilets and showerheads and high efficiency front load clothes washers. The estimated savings that could be achieved by this project assume 3 persons/home meeting 100% new efficiency standards of 1.28 gpf toilets, 25 gpl clothes washers, and 2.0 gpm showerheads.

If a 100% level of participation by the community is achieved, this could provide annual savings of about 750 acre-feet per year at a total cost of about $1,000,000 through 2020. About 2/3rds of the savings would be realized by single-family homes and about 1/3rd of the total water savings would come from multi-family residents. This program requires little ongoing effort or cost by consumers beyond the initial change-out and, because costs are comparatively minimal, implementation of this program is considered by the NRC to be akin to going after the low hanging fruit for achieveing water conservation.

2. Well Park Irrigation Project – This recommendation involves redirecting 4 existing intermediate aquifer well outputs to park irrigation use only and contemplates drilling 10 new wells of between 300 – 500 ft each. Although this recommendation is not strictly water conservation per se, using lower quality well water for park irrigation means higher quality potable water is not otherwise required for this use.

The total cost of this conversion project is about $7,230,000 and will produce an estimated reduction of potable water use of 400 acre-feet or about 1 million gallon per day during the irrigation season. Although not the most cost-effective measure, this recommendation has the highest degree of surety of effect – in other words, if the City spends the money, it is functionally guaranteed these levels of water savings (i.e. reductions of demand on the potable water system) would be achieved.

3. Smart Metering Project – This project involves the expenditure of about $3,500,000 (including a 20% contingency) to purchase “Smart Meters” to replace the City’s aging mechanical meters. Already, most neighboring cities have already switched to these types of meters including Sacramento and Woodland. The water meters in Davis are otherwise becoming aged and nearing the end of their useful life cycle length so replacement would otherwise still be required in the near or foreseeable future and it only makes sense to replace the older design meters with Smart Meters for the following reasons.

Smart meters allow instantaneous, real-time determination of water usage patterns allowing customers to profile their water usage to determine how water is used and to detect leaks. Elimination of only about half of the estimated leaks in residential customers’ homes in Davis would provide estimated water savings of about 700 acre-feet per year throughout the City.

This estimate is subject to the residential customer actually fixing leaks identified by Smart Meters. The City’s success rate in getting residential customers to fix leaks in their system in a timely manner, however, has been inconsistent and questionable at best. Thus, a very aggressive outreach and education program would be required for the City to realize the full value of savings from this project.

4. Outdoor Irrigation Water Management – As much as 50% of outdoor water use for irrigation in the City is excessive and above the needs of healthy plants. Reducing this excessive irrigation could save as much as 850 acre-feet per year. It would require a very comprehensive program of rate and tariff restructuring to provide incentives for watering during off-peak hours and retrofitting of some plumbing and irrigation systems to allow for proper use of “Smart” Irrigation Controllers.

Thus, realization of these savings may not be achievable without some type of rebate program. This program has the potential to reduce irrigation water needs by residential, commercial, and educational users by almost 850 acre-feet per year. But it will require an aggressive outreach and educational program combined with structuring time-of-day water usage rates (also allowed with the installation of Smart Meters). Not counting the cost of the Smart Meters identified above, outdoor water conservation program implementation costs may be only about $500,000.

This program goal relies almost completely on changing people’s behavior, however. So although it has by far the most cost-effective return on investment of the 4 programs recommended by the NRC, it also has the lowest probability of success unless extensive outreach and public education are effectively deployed.

Other Rate-Setting and Billing Recommendation

Following discussion of the specifics of these programs, it became apparent that the outreach component of some programs would be critical in terms of affecting consumer attitudes sufficient to stimulate them to undertake the steps desired to reduce their water usage. Most consumers now have little idea how much water they use and for what purposes. The City’s current billing methodology does little to help consumers in this regard. The NRC thus believes a few simple changes in how the City bills and displays its billing charges could go a long way toward effecting citizen behavioral changes.

For instance,

1)    The City should go to monthly billing instead of bi-monthly to stimulate awareness of water usage and changes from month-to-month.

2)    The City should report usage and bill based on gallons used instead of by 100 cubic feet used. Most consumers simply cannot relate a 100 cubic foot volume to everyday usage in their lives.

3)    The City should also report average usage for a household each month and display graphically how this usage compares to the usage of other households in the Davis community. This would enable high volume users to clearly identify high usage patterns and focus on reducing their usage to more normal patterns.

Additionally, as stated above, the City should fully embrace the capabilities of smart meters by going to time-of-day water usage charging to reduce peak hour usage during the irrigation season and towards more tiered usage tariffs to reduce overall consumption.

Management of the Process and Next Steps

Recognizing the uncertainty of achieving some of the water savings obtainable under this comprehensive program because the savings sought are dependent on consumer behavioral changes, the NRC intends to use adaptive management approach to implementing the 20% demand reduction plan. This will involve detailed annual analysis of water usage in the City followed by an assessment, evaluation, and recommendation process.

The NRC intends to provide such annual recommendations each February in the future, based on recent per capita water use data and water savings information over the past 12 months, to define the mix of measures that worked or did not work and then to implement changes in the upcoming year to stay on target.

The next steps for this NRC process to move forward are as follows:

1. Present final recommendations to City Council and the W.A.C in the Summer 2012 for review and guidance;

2. The NRC will then develop more detailed budgets following detailed engineering review in the Fall of 2012;

3. The NRC will conduct its first annual assessment in February 2013.

Alan Pryor is a member of City of Davis Natural Resources Commission

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