By Rich Anderson
April 25, 2011

Napa (CA) Mayor Jill Techel was presented with the 2011 U.S. Conference of Mayors Water Conservation Achievement Award on March 17 at a joint city council/planning commission meeting. Napa is one of two cities selected by a panel of independent judges as leading the nation's principal cities in water conservation achievement. Siemens Water Technologies Corp. Western Regional Manager Brian Shugrue presented the award to Techel, who accepted it on behalf of the city, the council, and the city water staff, whom she said deserved much of the credit.

Napa has a city population of 76,915, but the population served by its water treatment plants totals approximately 85,000 both inside and outside the city's rural urban limit (RUL). The city is surrounded by moderate industrial development, mixed density residential development, and, as part of Napa County, has significant agricultural land use in and around the city.

The city began serious water conservation efforts during the statewide drought of 1987-1992. By 2002, it had joined the California Urban Water Conservation Council and signed the Memorandum of Understanding (MOU) Regarding Urban Water Conservation in California. MOU signatories agree to make good faith effort to implement a prescribed list of Best Management Practices with specific implementation schedules and coverage requirements.

It should be noted that MOU is a voluntary program, but has serious implementation and accountability requirements. MOU is widely participated in by California cities. The previous governor and legislature, however, imposed a statewide 20 percent per capita demand reduction target for 2020, making urban water conservation even more essential going forward.

Napa can draw water from two local reservoirs and from state water project entitlements. Lake Hennessey has surface stores 31,000 acre-ft (10.1 billion gallons). Milliken Reservoir stores up to 1,400 acre-ft (456 million gallons) and has the highest quality source water. State water project entitlements provide up to 21,900 acre-ft (7.1 billion gallons) annually, but allocations are typically limited by state water supply conditions.

To take advantage of its state water entitlements, the city has upgraded the Edward I. Barwick Jamieson Canyon Water Treatment Plant from 12 million gallons per day (MGD) to 20 MGD. The Jamieson Canyon plant has been chosen as the primary operating treatment plant, although there is significant treatment capacity at Lake Hennessey (20 MGD), and Milliken Reservoir (four MGD, primarily for summer-only use). The Jamieson Canyon facility will meet most of the city's demand, and reducing use of the other treatment plants will save local source water for use in critical dry years.

City water staff estimates that treated water demand averages 22 MGD during peak summer season, and eight to 15 MGD in the off'season months. Total annual treated water demand ranges from 4.4 to 5.3 billion gallons. It should be noted that most of the wineries and vineyards in and around Napa do not draw on the city's treated water. Napa's demand is primarily residential, with landscape irrigation and annual evapotranspiration loss having a significant impact on supply/demand management.

Napa reports that year 2010 water use reduction via their conservation program is 33 gallons per capita per day (GPCD). The reduction is based on comparison with average use over the six-year baseline period (1997-2002) that preceded the city's signing of the California MOU. The reduction amounts to an estimated annual savings of 1.025 billion gallons (a 19 percent reduction). Reductions achieved in the residential sector accounted for 70 percent (8,352 Gallons per capita [GPC], or 23 GPCD). The remaining 30 percent of reductions were achieved in the commercial/institutional sector (3,580 GPC, or ten GPCD).

"Our demand management program is a three-legged stool of recycled water, efficiency in new construction, and water'saving incentives for existing customers," says Napa's Water Resources Analyst Patrick Costello. One leg of the program simply reduces demand for potable water by switching irrigation customers to recycled water. The city struck an agreement in 1998 with the Napa Sanitation District where tertiary treated wastewater is piped to specific areas where significant irrigation needs are now fully or partially satisfied with that recycled water. Anchor customers and revenue loss compensation were necessary for the economics of the agreement to make sense. Initial recycled water customers include the municipal golf course, a large corporate park, and a hotel resort. The system can be expanded over time as large use customers are identified and funding becomes available.

A second leg of the program involves new land development. The city adopted a local ordinance in 1991 that requires developers to offset up to 100 percent of the projected water demand of their new projects by reducing demand elsewhere in the city. This requirement is satisfied in a number of ways. The primary one is to replace older high-water-use toilets in existing residences with new high efficiency toilets (HETs). More recently, the city adopted high-performance building regulations that require 30 percent more efficient water fixtures in non-residential buildings. This requirement exceeds the state's CALGreen standard that requires a 20 percent greater efficiency for all fixtures. The city also has water-efficient landscape standards that effectively restrict lawn area in new development by imposing a stringent water budget.

A third leg of the program involves an assortment of education and incentives for existing water users to reduce potable demand. One program element is called "Cash for Grass," where homeowners are given a cash rebate for replacing lawn with water-efficient gardens. Homeowners are also eligible for incentives if they choose high-efficiency appliances such as front-loading clothes washers. One of the most innovative elements of the Napa program is Central Control Irrigation for 22 schools and 25 city parks. Two systems employ localized weather stations strategically located to monitor real-time weather conditions and stream data to specialized software that controls master valves to optimize scheduling and avoid irrigation during precipitation events. The software can also detect leaks via flow sensors and respond by limiting water flow. This saves response time to find and fix leaks; and it saves having to send personnel into the field, reducing the associated vehicle emissions impacts.

Bay Friendly training is a new part of the water education program. Napa began the local offering in 2010 to train professional landscapers on seven principles to foster soil health, conserve water and other resources while reducing waste and preventing pollution. Professionals that complete the program are qualified as Bay-Friendly Landscapers, and the city promotes them as part of its "Cash for Grass" rebate program. Bay Friendly Landscaping is a multi-county effort, and each community participates by providing training on a voluntary basis. Taken as a whole, the program is effective in reducing runoff into the bay.

"We were proud to win this award and excited that it came with a $10,000 check for the city. We will be investing it in more water conservation programs so we can continue to educate our residents on ways we can all conserve and ensure water supplies for future generations," said Techel.

Costello reports significant energy use reductions are associated with reduced supply, treatment, and distribution of water, and reduced wastewater treatment (for indoor savings). Napa's 2010 water savings correlate with 2.77 million kWh of energy savings, or 32 kWh per capita, using the California Energy Commission's Northern California water-energy factor of 3.95 kWh per 1,000 gallons (1.45 kWh for outdoor water). The water savings also correlate with a 1.45 million pound reduction in CO2 emissions, or 17 pounds CO2 per capita, using Pacific Gas and Electric Company's Carbon Footprint Calculator. About half of the water savings result from reduced indoor use, accounting for a subsequent reduction in wastewater discharges and sewage treatment by more than 500 million gallons, or 5,800 gallons per capita.