Implementation of an Integrated Water Management Program for the Rancho Murieta Community Services District
Abstract:California faces an uncertain future in supplying water to its projected population of 52 million in the year 2030. To achieve such a feat, the State's Recycled Water Task Force found that the water supply must be augmented and made more efficient through, among others, the use of water recycling and conservation.
The Rancho Murieta Community Services District's (District's) water supply consists of seasonal diversion from the Consumnes River that is normally diverted into three storage reservoirs. During average rainfall events, diversions provide adequate supply for consumptive uses and storage reservoir replenishment. However, during dry years, the river is subject to drought restrictions and as a result the District is faced with depleted storage reservoirs. Looking into the future, this condition will worsen and ultimately result in water supply shortages.
In addition to water supply concerns, the District was also met with developing an additional treated effluent disposal method, as the capacity of the existing disposal method was quickly approaching.
To address these challenges in a holistic manner and to provide a roadmap for maximizing the beneficial use of the community's water resources, the District initiated the Integrated Water Master Plan Project (Project).
The Project (completed in November 2006) recommended a multi-faceted and integrated solution (as described in Figure 1). The first two components (mandatory drought reductions and reduced water allocations for large estates) are being considered by the District's Board. The remaining recommended program components to maximize the beneficial use of existing water supplies are implementation of a conservation pricing strategy and a residential recycled water program.
Although the reduction in demand, estimated to be 3.5%, is not large, a conservation pricing strategy promotes community-wide awareness and water conservation practices. Thus, the District initiated a comprehensive review of conservation-based water rate structures to determine whether there was an alternate rate structure that would focus on efficient water practices, but still be flexible enough to provide a conservation signal during changing water supply conditions.
As part of the Conservation Pricing Study, the District explored a number of alternative rate structures that were more contemporary in design, including uniform rate structures, inverted block rate structures and seasonal rate structures, as well as the implementation of drought surcharge analysis.
A key challenge of the study was developing a new rate structure that would minimize transition issues, including (1) impacts to low- and high-use customers from a change in rate structure, (2) data constraints and rate design issues when attempting to meet target revenue levels, (3) utility billing system constraints, (4) explaining the change in rate structure to customers, and (5) encouraging the use of recycled water for landscape irrigation through monetary benefits.
An inverted block rate structure for residential customers, along with adoption of the drought surcharges, was ultimately recommended. The rate structures, as developed, should minimize impacts to the “average” customer, while those high use “inefficient or wasteful” customers will see greater impacts.
Recycled Water Program
In addition to finding that the District's existing water supplies would not be sufficient to meet future demands, the Project also found that additional wastewater effluent disposal would be required in the future because treated effluent production would surpass golf course irrigation needs. To reduce raw water supply demands and address future effluent disposal limitations, the District initiated a study to assess the feasibility of a residential recycled water program. The study examines the technical feasibility of implementing a residential recycled water program as well as the administrative, regulatory, and financial components which must also be addressed.
The feasibility study identified the following challenges associated with administrative and regulatory requirements: (1) program oversight including management, operations and compliance, (2) development of standards and user agreements, (3) approval of a master reclamation permit, and (4) public outreach to foster involvement and promote education.
The technical analysis found that approximately 10% of the total future water demand could be met using recycled water for residential irrigation. Moreover, the study identified several major benefits of program implementation, including reduction of future drought deficits, reducing the planned expansion of the water treatment plant, and improvement of reservoir waterline aesthetics. These benefits were then used to distribute program costs fairly and appropriately among the beneficiaries.
Document Type: Research Article
Publication date: January 1, 2008
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