CURRENT PROJECT STATUS:
The City of Longview and Beacon Hill Water & Sewer District (BHWSD) supply customers with groundwater sourced and treated at the Mint Farm Regional Water Treatment Plant (RWTP). The Mint Farm RWTP reliably produces drinking water that meets all regulatory standards but a 2014 survey found the majority of customers were unsatisfied. In 2016, the City investigated going back to the Cowlitz River using horizontal collector wells but this option is no longer being considered due to disappointing water quality results. Instead, focus shifted to improve water quality through optimization of the Mint Farm RWTP.
In summer, 2018 the City will commission an air injection system at the Mint Farm RWTP to increase the amount of dissolved oxygen in the water. Aeration is simple and widely used for corrosion control, but also removes hydrogen sulfide and ammonia which tend to cause taste and odor issues. Increasing the dissolved oxygen will also help harden pipe scale and prevent iron release in the distribution system. Once the system is commissioned, it will take several months to slowly raise the amount of dissolved oxygen to meet target levels. Long term, if dissolved oxygen can reduce the dependency on chlorine to maintain a stable distribution system, we hope to reduce the amount of chlorine added to the water.
Based on an average increase of $12 to $15 per month for a typical single family household, a decision was made not to remove silica. This decision may be revisited at a later date once benefits of dissolved oxygen are seen.
Horizontal Collector Well Feasibility Study
Exploratory wells were drilled in January, 2016 to evaluate four possible sites where a horizontal collector well could be located on the Cowlitz River. Two sites proved feasible in regards to capacity but water quality testing showed high levels of iron, manganese, hardness and silica, the same constituents which have caused many of our current customer complaints.
Customer Advisory Committee
In 2015, the City Council and BHWSD commissioners appointed a Customer Advisory Committee (CAC) to review water supply options. After considering options, the CAC recommended developing a new source on the Cowlitz River using horizontal collector wells. In March, 2016 the CAC reconvened to discuss the results of exploratory drilling and recommended further investigating Riverside Park and/or Rocky Point.
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Frequently Asked Questions:
Can't find what you're looking for? Click here to view Frequently Asked Questions.
Water Fact Sheets:
Please check out these links to read fact sheets prepared by Intertox Inc., an independent toxicologist expert with information about water minerals:
News From the Well:
Please check out these Daily News inserts for water quality updates provided to customers:
To make sure the Mint Farm aquifer is protected from contamination, the City developed a program to monitor changes in water quality. For more information, visit the City's Wellhead Protection Program.
Please check out the following presentations regarding updated water quality information, by clicking on the following links.
Public Outreach Documents:
Please check out the following handouts for tips on inspecting your hot and cold water plumbing system and other questions circulated in bill stuffers and the local paper addressing water quality concerns.
Letters from Concerned Citizens:
Formal letters from City staff responding to questions and concerns about issues relating to the Mint Farm groundwater source and water quality.
Distribution System Water Quality
To better address water quality issues, the City regularly samples the distribution system to monitor changes in customer water quality. More information is available by clicking on the following links:
Distribution System Sampling Location Map
Distribution System Sampling Plan and Data Record
Other Related Project Information and Reports:
- 05.18.2017 Silica Removal Alternatives Attachments - A technical report containing results of bench testing done to evaluate treatment options for silica removal.
- 03.09.2016 Organic Nitrogen Removal - A technical memorandum explaining the test methods and results of work done to evaluate interim measures to remove organic nitrogen which could help address issues related to chlorine taste and odor.
- 07.29.2015 Home Plumbing Study - Results of water quality profiling done at two residential homes to better understand if the chemistry of the water changes between the distribution system main and the customer's tap.
- 06-25-2015 Chlorine Demand and Decay (CDD) Study - A comparison of chlorine demand and decay characteristics of each production well to determine which well has the most stable free chlorine residual and least tendency to result in combined chlorine species.
- 04-27-2015 Flavor Rating Assessment - Results of taste and odor testing performed by Seattle Public Utility to rate Longview's drinking water for offensive taste and odors.
- 06-06-2014 Silica White Paper - Provides background on silica and summarizes treatment options to remove it. This paper is not intended to provide an exhaustive review on silica but does provide an overview of the key aspects of silica chemistry which are necessary to evaluate the feasibility of treatment options for silica removal.
- 11-18-2013 Tracer Study Report - A report submitted to the Washington State Department of Health in compliance with the Groundwater Rule describing the results of a chlorine contact time tracer study and demonstrating CT6 for 4-log treatment at the Mint Farm RWTP.
- 09-14-2012 Mint Farm Wellfield Source Approval (less appendices) - In accordance with WAC 246-290-139, this report was submitted to the Washington State Department of Health for regulatory approval of the Mint Farm wellfield. It summarizes the initial planning, engineering and hydrogeological evaluation, well logs and water quality information for each of the four wells.
- 09-14-2012 Mint Farm Wellfield Source Approval (with full appendices).
- 08-23-2012 Water System Start-Up Plan - Start-up of the new Mint Farm RWTP will change the direction of flow in certain areas of the distribution system. Flow reversal, and the change from a surface water to a groundwater, can create problems. This plan describes measures taken to prevent issues including flushing, reservoir cleaning, water modeling, pH adjustment, increased monitoring, and use of citizen sentinels to provide early detection.
03-29-2011 Mint Farm WTP Corrosion Control Report
- EPA published the Lead and Copper Rule (LCR) in 1991 to reduce lead and copper levels in water by reducing the corrosivity of the water in the distribution system and reducing the corrosion of plumbing materials containing lead and copper. This report presents the City’s strategy to control corrosion in compliance with the LCR.
- 03-14-2011 SEPA Amendment for Pipeline Re-Alignment - In accordance with SEPA rules and WAC 197-11, the change in alignment for the transmission main was also submittal for SEPA review.
- 03-02-2011 NEPA Amendment for Pipeline Re-Alignment - Due to difficulty in acquiring railroad easements, an amendment was required for an alternative alignment of transmission main. Except for its location, the details of the transmission main as described in the original Environmental Information Document remain the same.
- 08-13-2010 NEPA Finding of No Significant Impact (FONSI) - The Environmental Protection Agency conducted a review of the Mint Farm RWTP project and issued a determination that the project will not result in significant adverse effect, meets all requirement of applicable federal, state and local laws, regulations, statues and Executive Orders and is consistent with the Cowlitz County Comprehensive Plan and Growth Management Act.
- 08-13-2010 NEPA Environmental Impact Document (EID) - A detailed description of the Mint Farm RWTP project, the no action alternative and other alternatives considered but rejected. It evaluates human and environmental effects including wetlands, coastal zones, archaeological resources, floodplains, endangered species, air and water quality, and how to mitigate impacts.
- 07-19-2010 Pilot Study Summary - A pilot study to confirm performance of greensand filtration using water drawn from deep monitoring well DW-9, located nearer to future production wells. Dw-9 is lower in iron, manganese and arsenic than the Prudential Blvd test well.
- 06-07-2010 Mint Farm WTP Geotechnical Report - A report summarizing sub-surface investigation, exploratory borings and lab results for the Mint Farm RWTP and associated transmission main to connect the plant to the City’s distribution system.
- 03-2010 Preliminary Design Report - A comprehensive report describing the history of the water supply project, why it's necessary and what's been done to investigate it.
- 03-08-10 Environmental Site Assessment - Detailed investigation of work done to identify the potential for on- or off-site conditions to impact the Mint Farm well field. Includes an in-depth review of historical activities, file review with regulatory agencies, site recon and extensive analysis of soil and groundwater samples taken from the Mint Farm.
- 01-04-10 Human Health Risk Assessment - A water quality assessment of the available water supply sources - Cowlitz River, Columbia River and Mint Farm aquifer. This report compares the three sources and evaluates whether the groundwater source is a safe supply of drinking water.
- 09-02-2009 Mint Farm Groundwater Granular Media Study Report - The results of a pilot study to treat raw water pumped from the Prudential Blvd test well and to determine whether iron, manganese and arsenic could be removed using three types of conventional granular media.
- 05-02-2009 Mint Farm Groundwater Pilot Study Protocol - The plan developed for water treatment trials describing the pilot study equipment, how it will be operated, treated water quality goals, and outlining the sampling and analysis plan for the raw and treated waters.
- 04-28-2009 Water Quality Sampling and Analysis Protocol - A plan describing where and how water and soil samples will be collected to evaluate the Mint Farm source. Includes an analyte list for testing based on regulation, emerging contaminants which may be regulated in the future and unregulated contaminants common to historical and industrial activity near the Mint Farm.
5-7-2008 - Constructability Study - A report identifying deficiencies, needed improvements, cost estimates, and construction schedule for possible rehab of the Fishers Lane water treatment plant.
- 05-05-2008 - GSI Environmental Review - A third party environmental review of the area near the proposed Mint Farm wellfield looking for existing potential contaminant sources due to industrial and commercial operations, and evaluating the risk of potential contamination.
- 01-09-2008 Columbia River Water Quality Report - Laboratory results of the analysis of untreated water samples collected from the Columbia River. Includes inorganic compounds, volatile compounds, synthetic organics compounds, herbicides and some unregulated contaminants.
- 12-14-2007 - GSI Peer Review - A second opinion of the groundwater evaluation provided in the 01-2007 Prudential Blvd Test Well Report. The peer review focuses on whether the aquifer is productive enough to meet projected water demand, whether the supply can be sustained, and includes a discussion of issues related to siting wells in an industrial park.
9-4-2007 - Value Engineering Study - A review of water quality alternatives focusing on options to rehabilitate Fishers Lane or relocate the source and treatment to the Mint Farm Industrial Park.
- 01-2007 Prudential Blvd Test Well Report - A summary of the Prudential Blvd test well (formerly Weber Ave test well) which was the first exploratory well drilled in the Mint Farm. Describes the drilling, construction, testing, geology, hydrogeology and water quality at this location.