Agenda - Council Work Session - 02/08/2021

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CC Work Session 2. 1. Meeting Date: 02/08/2021 Information Title: Consider Next Steps for Implementation of Centralized Water Treatment Plant Purpose/Background: The purpose of this case is to receive consensus direction from the City Council on how staff should proceed to implement the Centralized Water Treatment Plant project. Attached is a copy of the latest draft Feasibility Study dated February 3, 2021 for the proposed centralized water treatment plant as prepared by SEH, Inc. The study is filled with information on the City's water supply source, water quality and quantity, water supply system infrastructure, water treatment process options and recommendations, water treatment plant site evaluations, estimated costs, funding sources, effect on water rates, and project schedule. Staff's intent is not to duplicate the information from the Feasibility Study within this case. Instead, only information that Council members may find most helpful in understanding the need for the centralized water treatment plant project is presented below. The City of Ramsey utilizes groundwater from the Tunnel City-Wonewoc (TCW) aquifer, formerly known as the Franconia -Ironton -Galesville (FIG) aquifer, as its exclusive source of drinking water. A total of eight municipal water supply wells exist, with seven being available to supply water to the City's municipal water users. Water test results from the municipal wells show that concentrations of manganese range from 0.02 mg/L to 0.37 mg/L. The Minnesota Department of Health (MDH) recently established Health Based Values (HBV) for manganese of 0.100 mg/L for bottle-fed infants, and 0.300 mg/L for everyone else. Four of Ramsey's eight water supply wells exceed the MDH HBV for manganese. In 2019, MDH recommended that the City develop short and long term plans to reduce manganese concentrations in our water supply system. In April of 2019, the City began supplying water to municipal water users using only the three wells with the lowest manganese concentrations to make sure manganese concentrations throughout the water supply system would not exceed the MDH Health Based Value (HBV) for manganese of 0.100 mg/L. The long term solution requires construction of a water treatment plant to remove manganese from the municipal water supply system. To properly plan for long-term solutions to reduce manganese and iron concentrations in the municipal water supply system, to properly treat any other emerging contaminants, and to ensure the existing aquifer used as the City's sole groundwater source has adequate capacity to meet the future needs of the City, Staff solicited proposals from qualified consultants to provide professional engineering services under the following three general areas. 1. Analyze Source Water. Analyze and report on the overall accessibility, capacity, chemistry and limitations of the Tunnel City/Wonewoc (TCW) aquifer, the existing source water for the City of Ramsey's municipal groundwater supply system, and on the long-term viability of continuing to use the TCW aquifer as the sole source of water for the municipal water supply system. This will allow the selected consultant to adequately prepare a preliminary design report by understanding the chemistry of the municipal groundwater supply system and therefore which primary, secondary and/or emerging contaminants will need to be treated over the anticipated life of the facility. This work will also allow the selected consultant to provide recommendations on the need for and use of alternative sources of water. 2. Develop Water Model. Develop a model of the City of Ramsey's municipal water supply system using an industry standard software program. This model will allow the selected consultant to adequately prepare a preliminary design report, and will allow the City to evaluate future operations throughout the system by considering variable flow regimes when water is drawn from different wells and storage tanks at different