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Building a Shared WTP
In the Main - A technical assistance newsletter for Public Water Suppliers
September 2008
Temporary Water Main and Service Connections
By Margaret Finn and Jennifer Olivier
As of June 2008, the Mattapoisett River Valley Water District (MRVWD) has started up its new $16.5 million water treatment facility in the town of Mattapoisett. The MRVWD has four member towns: Fairhaven, Marion, Rochester, and Mattapoisett (although Rochester does not currently have a drinking water source). The towns have realized a $4.9 million cost savings by working together and can serve as a model for other towns looking to reduce capital costs.
Advantages to Working Together
As a district, the member towns are able to:
- Use existing water resources
- Avoid new source development costs
- Minimize the cost of treatment (economies of scale, 2% State Revolving Fund SRF) loan, and share Operation and Maintenance (O&M) costs)
- Make use of the best available technology treatment for conventional cost
- Share water resources to meet future demands
- Provide emergency back-up and redundancy of water supply
Estimated cost savings analysis of individual versus district share project costs:
| |
Capital Costs |
|
Individual ($M) |
District Share ($M) |
| Fairhaven |
$10.3 |
$9.1 |
| Mattapoisett |
$7.4 |
$5.0 |
| Marion |
$3.7 |
$2.4 |
| Total |
$21.4 |
$16.5 |
| |
Capital Cost Savings of $4.9M |
The Water Treatment Facility
The water treatment facility has the capacity to treat 6 mgd of water, drawn from 8 wells belonging to Mattapoisett, Marion, and Fairhaven, which are located in Mattapoisett and Rochester. Treatment at the facility includes oxidation with ozone, followed by membrane ultrafiltration with Koch membrane filters for the removal of iron and manganese. Ultrafiltration provides an extra level of treatment beyond conventional green sand filtration. Citric acid is used to clean the membranes. Potassium hydroxide is used for pH adjustment. The project also includes four miles of raw and finished water mains, rehab of eight wells, and a three-town supervisory control and data acquisition (SCADA) system.
History
The towns of Fairhaven, Marion, Rochester, and Mattapoisett have been working together since the 1980's to protect their water supply, which is the Mattapoisett River aquifer. In 1983 legislation formed an advisory committee (Mattapoisett River Valley Water Supply Protection Advisory Committee). An additional act of legislation in 1997 allowed this advisory committee to assess up to $0.01 for every 100 gallons pumped from the Mattapoisett River aquifer. The monies collected were deposited in a water supply protection fund. The legislation allowed the committee to use the fund for acquiring land, conducting engineering studies, or public education.
More recently, the committee observed that eight of the water supplies for the towns exhibited declining water quality and loss of supply capacity due to iron and manganese. These wells had a total capacity of 6 million gallons per day (mgd), of which only 4 mgd was available. In 2003 the committee funded a study, completed by Tata & Howard, Inc., to look at water quality and treatment options, supply capacity, future needs, redundancy, and emergency backup. In 2004 the study, which concluded that a new regional water treatment facility (WTF) was the most cost-effective solution to service current and future water needs of the member communities, was completed. The establishment of the MRVWD was unanimously approved by the four towns and then by the state legislature. By 2005, the design was completed by Tata & Howard, Inc. and the committee had applied for funding.
The Mattapoisett River Valley Water District was awarded a low-interest (2%) 20-year loan for the construction of the facility through the SRF, administered by the Massachusetts Department of Environmental Protection (MassDEP) and the Massachusetts Water Pollution Abatement Trust.
Construction of the treatment facility began in July 2006. The treatment facility was expected to start servicing the towns of Fairhaven, Marion, and Mattapoisett by the end of July 2008. The town of Rochester has water rights in the valley and can purchase supply from the district in the future should the town develop a water department.
How this Arrangement Works
The MRVWD owns the WTF, the raw water transmission mains from the wells, the finished water transmission mains from the WTF to the town transmission mains, and the control/metering valves at the remote connections. The towns continue to own their wells and their own distribution systems.
The Mattapoisett Water Department agreed to be lead community for the WTF and provide certified operator(s) and O&M services. Compensation for O&M at the facility is proportionally based on the volume of water treated by member towns. However, each member town provides the O&M of individual well pumping stations after district upgrades are completed, with the expectation that member towns will repair wells in a timely fashion.
By district agreement, the rates for any given year are based on the highest average annual rate of the member towns. Members that supply excess water to the district are compensated at a single rate per 100 cubic feet of raw water. These rates are reviewed annually based on each member's estimated pumping costs.
The district, which includes representatives from each town:
- Sets policies (establishes fees, determines financing, and rate-setting criteria and formulas)
- Plans for peak summer demands and emergencies
- Balances withdrawals relative to seasonal variations, water management restrictions, and environmental impacts
- Develops water conservation guidelines and programs to be implemented by the towns.
Towns not participating financially (at least 10%) do not have voting rights on financial matters.
The district sets limitations on sale of water to non-district members and must approve all proposed developments within the Mattapoisett River Valley requiring at least 100,000 gpd. In addition, they purchased about 40 acres of land within the wells' Zone IIs approximately 2 years ago and this fall plan to purchase an additional 22 acres.
Should the town of Rochester be interested in drawing water from the facility, by agreement the buy-in formula will be based on the proportional need of the community compared to the appraised value of the facility and a payment share for engineering and pump upgrades and the original capital cost.
For more information please contact either Margaret.Finn@state.ma.us (617-292-5746) or Jennifer.Olivier@state.ma.us (617-654-5746).
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