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10-05-11 JWC Agenda PacketAGENDA JOINT WATER COMMISSION 1:30 pm — October 5, 2011 Council Conference Room Golden Valley City Hall 1. Call to Order 2. Approval of Minutes — September 7, 2011 3. Update on 24 -Inch Valve Replacement (Mathisen) 4. Water Interaction Study Proposal (Clancy) 5. Other Business 6. Adjournment JOINT WATER COMMISSION MINUTES Golden Valley - Crystal - New Hope Meeting of September 7, 2011 The Golden Valley — Crystal — New Hope Joint Water Commission meeting was called to order at 1:30 pm, in the City of Golden Valley Council Conference Room. Commissioners Present Tom Burt, City Manager, Golden Valley Anne Norris, City Manager, Crystal Kirk McDonald, City Manager, New Hope Staff Present Sue Virnig, Finance Director, Golden Valley Bert Tracy, Public Works Maintenance Manager, Golden Valley Dave Lemke, Utilities Maintenance Supervisor, Golden Valley Tom Mathisen, Director of Public Works, Crystal Randy Kloepper, Water and Sewer Superintendent, Crystal Guy Johnson, Director of Public Works, New Hope Pat Schutrop, Administrative Assistant, Golden Valley Minutes of July 13, 2011 MOVED by Norris, seconded by McDonald, the minutes of the July 13, 2011 meeting. and motion carried unanimously to approve Review CIP Proiects (Virnig) The JWC reviewed the status of the 2010-11 CIP projects. Tracy will work with the City of New Hope to get total control quote to add security for the SCADA system for the JWC to consider at the October 5th JWC meeting. Commissioners agreed to lowering or increasing any future years CIP funding by the balances remaining of closed projects. The TAC is working with New Hope and the Minnesota Department of Natural Resources to get the New Hope emergency well activated. The funding will fall within the $50,000 allocated in 2010. The TAC received the proposal from Barr Engineering Company for the backup water supply and will review for discussion with the JWC at the October 5th meeting. Virnig will provide the JWC with an updated CIP. 1AJoint Water CommissionUM Minutes\2011 JWC Minutes\09-07-11 JWC Minutes.doc Joint Water Commission September 7, 2011 Page 2 of 2 TAC Update (Mathisen) Update on New Hope Emergency Backup Well and Funding—see discussion above. 42nd Avenue Watermain—The TAC is continuing to work with Hennepin County. Bonestroo will not receive a notice to proceed for the pipe design until an agreement has been signed with the county. Other Business Burt prepared a draft letter to the City of Minneapolis as a follow-up to the recent May 11, 2011 meeting of the JWC's three city councils regarding the JWC's interest in reviewing the Minneapolis water rate study. Norris and McDonald agreed that Burt should finalize the letter and send to the City of Minneapolis. The Minneapolis Water Advisory Board met on Thursday, August 25. Minneapolis staff discussed the proposed 2012 Pro Forma, meter ownership, and project and studies . updates. Minneapolis is proposing a fixed base rate to its customers. Water rates will not change in 2012. Next Meeting The next meeting will be Wednesday, October 5, 2011, at 1:30 pm. Adiournment The meeting was adjourned at 1:50 pm. Thomas D. Burt, Chair ATTEST: Pat Schutrop, Recording Secretary (:\Joint Water CommissionUM Minutes\2011 JWC Minutes\09-07-11 JWC Minutes.doc 1171 Barr Engineering Company 4700 West 77th Street • Minneapolis, MN 55435-4803 Phone: 952-832-2600 • Fax: 952-832-2601 • www.barr.com An EEO Employer BARRMinneapolis, MN • Hibbing, MN • Duluth, MN . Ann Arbor, MI • Jefferson City, MO • Bismarck, ND October 4, 2011 Joint Water Commission City of Golden Valley 7800 Golden Valley Road Golden Valley, MN 55427 Re: Water Interaction Study Proposal Dear Joint Water Commission: The purpose of this letter is to provide the Joint Water Commission (JWC) with a proposal for performing a water interaction study intended to help understand the potential for unintended and undesirable chemical interactions if an emergency supply from a groundwater source is mixed in your system with the softened surface water from Minneapolis. This proposal contains the following sections: Project Understanding and Assumptions, Work Plan, Project Team, JWC Role, Schedule, and Cost Proposal. Project Understanding and Assumptions This study is the first of several that were recommended during a meeting held on August 1't at the Golden Valley City Hall. It is based on the following assumptions laid out during that meeting. • The JWC is studying the possibility of constructing an emergency water supply that would be used when an interruption of service from Minneapolis occurs. • The supply is intended for emergency use at this time but at some point in the future could become part of a system that would be the primary supply for the JWC. • The emergency supply would come from wells owned by the JWC and drilled into the Prairie du Chien aquifer. • Any future primary water supply that included these wells would be a softened supply. The JWC gets all of its water from the City of Minneapolis at this time. The water is a softened surface water that originates from the Mississippi River. Should the supply from Minneapolis become interrupted the JWC would like to have an emergency supply available to supply water to its customers. Studies to date have pointed to using wells drilled into the Prairie du Chien/Jordan aquifer as a viable emergency backup supply. The supply would be unsoftened groundwater since the construction of a full scale softening plant for emergency supply is cost prohibitive. A water interaction study is needed for several reasons. First, if an emergency supply using groundwater is used it will result in a different water quality than what is currently provided by Minneapolis. When the waters are mixed a variety of potentially undesirable chemical reactions could occur. It is in the JWC best interest to understand the potential reactions so you will be prepared in the event that they Joint Water Commission October 4`h, 2011 Page 2 occur, if for nothing else than to respond effectively to calls from concerned customers. Second, that reaction dictates the minimum level of treatment or other mitigation strategies you need to plan for as part of your emergency system. Finally, this study will provide information relevant to the treatment needed to convert the emergency source to your primary supply which is directly related to the size of site needed for a treatment plant. The groundwater source being considered is the Prairie du Chien and is known to be high in iron and manganese, relatively hard as compared to the water currently in the JWC system and will usually be at a different temperature than the water coming from Minneapolis. Numerous reactions are likely to take place when these waters are mixed. In addition, the inner walls of the JWC distribution network are likely coated with deposits related to the Minneapolis supply. While these deposits are harmless byproducts of the Minneapolis water they will react in some way with the emergency supply when it is introduced into your system. Again, understanding the reaction is in the JWC's best interests. This study is set up with two parts the first will be a computer based modeling effort using a software package called PHREEQC. The results of the computer modeling will be used to focus the second part of the work which will be a bench scale test that will help validate and calibrate the computer model. The ultimate goal of this work is to determine the minimum level of treatment needed for an emergency supply and help guide an understanding of what treatment would be needed for a full scale treatment system should the emergency supply be converted to a primary supply at some point in the future. Water Interaction Study Work Plan Study Objectives: The following objectives would be targeted by this study: 1. Identify potentially undesirable chemical interactions between the two sources of water. 2. Evaluate mitigation strategies for an emergency supply to avoid undesirable interactions. 3. Provide preliminary guidance as to the level of treatment needed for a permanent source. Study Tasks: The following is a description of the work to be done as part of this study: Task 1 Computer Based Modeling: Barr will use a computer based chemical interaction model called PHREEQC to evaluate the interaction of the two waters when they are mixed. We will then model mitigation treatment strategies that may be needed to address negative interactions such as precipitation of solids or formation of undesirable compounds. This task would use existing water quality data for both sources. The data should represent a range of seasonal quality and temperature variations for the Minneapolis source. No new data would be gathered during this phase. A computer based water quality model of the existing system, including the scale that may have built up on the inner pipe walls, will be developed using existing water quality data from Minneapolis. We assume the JWC will assist in obtaining water quality data from Minneapolis and a groundwater source that we will help identify. A preliminary list of the water quality data needed for the existing Minneapolis water and the proposed emergency supply includes but is not limited to: • cation and anion data • Iron and manganese concentrations • Dissolved oxygen concentrations • temperature • pH Joint Water Commission October 4`h, 2011 Page 3 • Total Alkalinity • hardness • dose ranges for treatment reagents used, such as chlorine and fluoride • concentration of organic compounds (i.e. TOC, DOC), or UV254 absorbance Once the existing conditions model is constructed we will run up to four different scenarios for emergency supply. Those include: 1. Adding an untreated raw groundwater to the existing system. (We understand this would not be done except in a severe emergency but this data will serve to define a base line condition). 2. Adding a minimally treated groundwater supply to the existing system. Minimal treatment would consist of disinfection only, and is assumed to be the minimum treatment needed to meet primary drinking water standards. 3. Adding a more heavily treated groundwater supply to the existing system. As an example, this might consist of adding a sequestering agent to prevent red water complaints. This level of treatment will be what is needed to meet primary and secondary drinking water standards. 4. Adding a fully softened supply to the system such as would occur in a future scenario where the JWC became its own supplier. The primary objective of this run will be to understand the long term interaction of the new water with the solids that may have built up on your inner pipe walls as discussed above. This scope of work is based on the assumption that major interactions will not occur. If significant detrimental interactions occur the scope outlined here will have to be amended to allow for additional analysis and model runs to identify the level of treatment needed to meet primary and secondary drinking water standards. Task 1 Deliverable: A technical memorandum detailing the results and a scope of work for the bench scale tests to calibrate/validate the modeling results. Task 2 Bench Scale Testing: Barr will work with a local lab to perform a bench scale study to validate the computer modeling. The bench test would also be set up to capture seasonal quality and temperature variations. Depending on the results of Task 1 the source of the groundwater could be the New Hope well and/or water from a neighboring community that performs the level of treatment anticipated for the end use in consideration. Task 2 Deliverable: A report detailing the results. The report will include guidance related to the minimum amount of treatment needed for an emergency supply and a preliminary recommendation related to a treatment system for a full scale softening system needed to convert the emergency supply to a primary supply. It will also include a scope of work for a pilot scale test needed to better inform final design of a softening plant. Note that the pilot scale test is not included in this work since it is not related to emergency supply. Project Team Barr has assembled a team to deliver the study described above. Below is a list of the team members that would be involved in the main efforts. Joint Water Commission October 0, 2011 Page 4 Brian LeMon will be the PIC for the work and manage the study. Brian has over 27 years of experience working with municipal water systems and has worked on several JWC projects. He is familiar with JWC infrastructure and water system operation. Ray Wuolo will assist in obtaining appropriate data for the groundwater sources. Todd DeJournett will head up the work related to the chemical interaction between softened Minneapolis water and unsoftened groundwater. Todd is a PHD environmental engineer and has extensive experience working in complicated chemical settings as they relate to human health and welfare and potable water systems. Scott Kyser is an environmental specialist with a master's degree in civil engineering. Scott will perform the PHREEQC modeling under Todd's supervision. Mark Ryan has experience working with chemical interactions and has a bachelors of science in civil engineering. He will work with the labs on the bench scale study under Todd's supervision. JWC Role Barr is requesting the JWC's involvement for two main tasks. The first will be to help obtain the water quality data needed from the City of Minneapolis for the finished water it delivers to the JWC. We would like four specific data points: 1. One representing the coldest temperature at which water is delivered annually, 2. Another representing the warmest temperature, 3. Another representing the quality during the spring season when taste and odor are an issue (this should represent a quality with some level of organics present), and finally 4. The average water quality delivered. Barr can assist in making the request but we will likely need JWC input to process what is needed. The second item for which we will need JWC input is to help define an acceptable quality of water to deliver during an emergency. This is ultimately subjective. We will recommend the minimum treatment needed to meet primary and secondary drinking water standards but those limits will not address the reactions likely to occur when the two waters are mixed. JWC assistance will be needed to help define a tolerable level of aesthetic water quality for your emergency supply. Project Schedule The work described in this proposal will be performed according to the following schedule. Receive raw water data Week 0 Complete Task 1 PHREEQC modeling Week 3 Complete Task 2 bench scale testing Week 7 Submit Draft Report Week 9 Joint Water Commission October 4th, 2011 Paee 5 Proposed Fees A summary of project costs is included in the table below. Task description Fee Effort in Hours Task 1 PHREEQC modeling $5,000 56 hours Task 2 Bench scale study $8,000 77 hours Meetings, analysis and report preparation $4,000 41 hours Lab costs $2,000 N/A Total $19,000 Barr looks forward to working with the JWC on this study and continuing our successful relationship. If you have any question please contact me at 952-8362-2774. If the proposal is acceptable to the JWC, please sign and date two copies of this sub agreement in the space provided below. Keep one copy for your records and return the other to Barr. BARR ENGINEERING COMPANY By Loll-� Brian K. LeMon Its Vice President Accepted this _ day of , 20 JOINT WATER COMMISSION By J:\Barr Work\Proposals\JWCUWC water interaction study.docx