City of Abbotsford - Water Education

The population of Abbotsford is approximately 2,000 people. While the City is located in a predominately agricultural area, Abbotsford has a significant industrial component.

Abbotsford has historically had challenges with an adequate water supply. Since 1970 the City has aggressively searched for water within the City boundary and surrounding area. Over 200 test well borings have been drilled. The well exploration program has not yielded enough water to keep pace with City growth.

In 2007, a large industrial customer in Abbotsford announced that they will be expanding and will require additional water of 300,000 to 350,000 gallons per day. This is a dramatic increase from 100,000 gallons per day and has had a negative effect on the water level at all of the City wells. The City responded by beginning a new water exploration search. The water exploration search covered an area of 400 square miles and an evaluation of other municipal water systems in a 30 mile radius of Abbotsford. The water exploration search was not successful in locating a ground water source of supply adequate to meet the required additional water demand.

The City of Abbotsford currently has a high quality water supply through the two existing water treatment plants. However, the volume of water available in the aquifer is in jeopardy with the increased water usage. If the aquifer is not allowed to recover from pumping, there is a risk that the aquifer could be temporarily or permanently damaged, and water will not be available to meet all of the customers' demands. Initial measures would be reduction of non-essential water use, such as lawn watering and vehicle washing. If more drastic measures are required, water may not be available for health, sanitary, and security uses.

The City experienced a very serious water supply issue in the spring of 2008 when a critical piece of equipment failed at existing Water Treatment Plant No. 2. The City was very close to running out of water during the two day period that this plant was out of commission. If a structure fire had taken place during the two day period, the City would have faced dire consequences. The health and safety of the City residents is currently at a high level of risk until significant new sources of water can be brought on-line.

On May 20, 2008, Wisconsin Department of Natural Resources (WDNR) conducted the 2008 annual waterworks inspection for the City of Abbotsford. The WDNR inspection focused on operation of the existing water system and potential health and safety issues resulting from excessive pumpage of water. WDNR stressed the importance of pursuing conservation measures and increasing source capacity. The WDNR letter noted that loss of positive pressure is considered a threat to the health and safety of the community. The letter also stated that without additional source capacity, a point will be reached where growth in the community will be limited by the amount of water that can be obtained for drinking.

The goal of this project is to provide an adequate, sustained water supply for the City of Abbotsford. SEH has prepared an Engineering Report that reviews the requirements, investigations, recommendations, and estimated construction costs for the proposed public water system improvements, which consist of a water treatment plant, wells, storage tank and distribution mains for the City of Abbotsford. This memo contains a summary of the Engineering Report.

Background

The City of Abbotsford is located in central Wisconsin, in portions of both Clark and Marathon Counties, at the intersection of Highways 13 and 29. The City is approximately 30 miles west of Wausau, and 60 miles east of Chippewa Falls.

Selected Alternative

The City of Abbotsford evaluated the three alternative solutions based on capital cost, present worth cost, sustainability and schedule. The present worth analysis (life cycle cost analysis) includes capital costs, operation and maintenance costs and short lived assets costs for a 40 year time period. Comparison factors evaluated were water source flow rate, water treatment requirements, distribution system or transmission main piping required, and timeliness in ability to meet water demand. Based on the City's evaluation, the third alternative was ranked above the other two because it had the lowest capital cost, comparable present worth costs and was the most sustainable alternative (groundwater is not sustainable as a long term water resource).

Surface Water Alternative

The proposed water system improvements project consists of a surface water supply with limited interim groundwater supply. The system consists of four components: Interim groundwater supply consisting of West Wellfield improvements, east water tower, industrial park distribution system improvements, and the Elm Brook surface water treatment plant.

The City recognizes that a surface water source will require a significant amount of time to construct the water treatment facilities. Because of the immediate need for additional water, the City is constructing an interim ground water supply that will provide 24,000 gallons per day. This water volume will not meet the needs of the industrial demand. However, it does provide a small amount of water in a short amount of time.

The City seeks to utilize the surface water from Elm Brook by treating it to a high quality using a multiple barrier concept. In 2009, the City of Abbotsford plans to develop a surface water source by utilizing water from the City's Wastewater Treatment Plant (WWTP) discharge to Elm Brook. This water will be treated to a high quality using a multiple barrier concept.

The components of the surface water treatment plant would be located on the east side of the City of Abbotsford, along a tributary to Elm Brook.

The City will construct a water intake at Elm Brook to collect surface water for the Elm Brook Water Treatment Plant. A raw water reservoir consisting of two ponds with a total storage capacity of 3 million gallons will be constructed between the surface water source and the treatment process.

Water Treatment Concept Plan

The water from Elm Brook will be pumped to the Water Treatment Plant (WTP) detention storage ponds. A series of ponds will hold 3 million gallons and will consist of two ponds where the water will then be pumped to pretreatment, consisting of rapid mix, flocculation and clarification. The water will then go through rapid sand filtration. After the rapid sand filtration, the water will be pumped through a microfiltration membrane unit, followed by a biologically active granular activated carbon filter and reverse osmosis, then to UV disinfection with an option to add hydrogen peroxide. Hydrogen peroxide may be required for pharmaceutical removal. After chlorine residual disinfection with contact time, the water will be pumped into the water distribution system and a 500,000 gallon water tower.

The water treatment plant will have a firm capacity of 750,000 gallons per day with additional filtration redundancy for an ultimate capacity 1,000,000 gallons per day. The plant will need to provide 5.5 log removal of Giardia, 5.5 log removal of Cryptosporidium and 4.0 log removal of Viruses. The proposed treatment process will provide for log removal values that significantly exceed the required values. Turbidity monitoring will be located prior to filtration. Turbidity and particle count monitoring will be provided after filtration. UV light intensity monitoring and chlorine residual monitoring will be provided after disinfection.

The treated water will be used to supply an industrial water system. The industrial water system will serve customers through a distribution system separate from the Abbotsford City water system. The two systems will be connected at a single point, with a check valve that will allow water to flow from the City system to the industrial system. In the case of a catastrophic event that shuts down the WWTP or water treatment plant, the City system will supply the industrial system. Even though water in the industrial system will be treated to potable water quality standards, water will not be allowed to flow from the industrial distribution system to the City distribution system.

The concept plan for the water treatment plant includes a water conservation effort by all customers served by the City of Abbotsford. One of the largest City industries is focusing on reducing water used during cleaning processes and increased vigilance by employees to reduce water usage where feasible in the plant. The conservation plan will also include all residential, commercial, institutional and other industrial customers.

The customers served by the proposed industrial water system will be part of the Eco-Industrial Park. The Eco-Industrial Park will not only include a sustainable water supply system, but all activities in the Park, including storm water treatment, solid waste recycling and energy management will have an environmental focus.

Cost Estimate

The estimated cost of the surface water alternative is $21.8 million. A summary of the cost estimate is listed below. A detailed cost breakdown for this alternative, including O&M costs, short lived assets and a present worth cost analysis are found in the Recommended Alternatives section.

1. West Wellfield $558,000

2. Water Tower and connecting water main $1,757,500

3. Distribution and Metering $1,148,600

4. Water Treatment Plant $14,503,500

5. Engineering $3,800,000

6. Legal $10,000

7. Administration $12,000

8. Land and Rights $50,000

9. Total costs $21,839,600

Conclusion and Recommendation

The three alternatives that were investigated by the City include purchased water from another municipality, developing a groundwater source of supply and developing a surface water source of supply, with interim groundwater wells.

The City has concerns about the viability and feasibility of depending only on groundwater as a source of supply when ground water levels are diminishing in volume. There are equal concerns surrounding the development of a water source that is located a substantial distance from the City. Adjacent communities are not able to financially support a pipeline initiative now or in the near future. The City is faced with an immediate need for water and cannot wait for other communities to experience a similar need for water.

The selected alternative is to quickly develop additional interim ground water supply that will take some of the immediate pressure off of the existing drilled wells, along with a water tower and industrial park water main. The selected alternative also includes the development of a surface water treatment plant that provides long term sustainable water to meet existing and future demands. This alternate was also selected due to the availability of a consistent quantity of water, close proximity to the City and costs that are significantly lower than the purchased water alternative (pipeline).