Extended Period Simulation and Hydraulic Study for Town of Avon, MA Water Division

Tata & Howard completed an Extended Period Simulation (EPS) hydraulic model of the water distribution system for the Town of Avon, Massachusetts. An EPS model was created to account for changes in the water distribution system over an extended period to include peak and minimum demands during both the summer and winter months. These changes included tank levels, pump controls, value operation, and demand variations.

The EPS model was used to estimate the water age in the water distribution system under winter and summer demand conditions. Water age is the time water takes to travel from a water supply source to a point within the distribution system.  It is used as an indicator of water quality based on the assumption that the older the water is, the greater the likelihood that water quality has deteriorated.  According to MassDEP Finished Water Storage Guidelines, a three to five-day complete water turnover is recommended in water storage tanks.

The EPS model was also utilized to evaluate the Town’s existing system operations. The model was used to determine the optimal tank operating range and the impact of the run times on the well pumps. Simulations were performed on both the Center Street and Page Street Tanks to evaluate operations under existing and projected average day demand (ADD), maximum day demand (MDD), and peak hour demands with a minimum pressure of 35 psi maintained throughout the distribution system.

In addition to analyzing the tank optimal operating levels, changes to the existing pump operations and the effect on tank levels and water age were evaluated. Two modified pump operations scenarios were evaluated. Both scenarios were run with the existing tank water level controls and allowing the Page Street Tank to drop four feet.  A second modified pump operation scenario evaluated the Town’s lead/lag system. Results for the pump and tank level operations under these simulations were recorded for both summer and winter operations.

Based on the results from each operational modification, Tata & Howard made several recommendations for improvement to the water distribution system. These included allowing the water level in the Page Street and Central Street tanks to drop an additional six feet to improve water age during both the summer and winter demands.

In addition, to help improve the water age in the tanks to an optimal three to five-day complete water turnover as recommended by MassDEP Finished Water Storage Guidelines, Tata & Howard suggested installing mixing systems in each tank.

Burbank Tank Rehabilitation – Millbury, MA

Burbank Tank, Millbury, MA  The Burbank Tank is a 110-year-old buried fieldstone tank located in Millbury, MA.  Due to concerns from MassDEP on the age and condition of the tank, the Aquarion Water Company contracted Tata & Howard to provide design specifications and DN Tanks was selected as the tank rehabilitation contractor for installing shotcreting lining to the fieldstone walls, pouring a new concrete floor and removing pipes within the tank that are no longer in use.  While the proposed work is not a structural fix for the tank, shotcreting the walls will reduce potential root intrusion, seal up areas of lost mortar, and reduce the potential for leakage.  The rehabilitation was undertaken in early 2017 and completed in 8 weeks.

The Burbank Tank is the only storage tank in the water distribution system.  Therefore, careful planning and evaluation of the system using the hydraulic model was required to review the options for operations without storage for an extended period of time.

Worcester, Massachusetts Hydraulic Modeling Services and Capital Efficiency Plan™

Tata & Howard completed a hydraulic model update and Capital Efficiency Plan™ for the City of Worcester. As part of the project, Tata & Howard updated and verified the City’s existing hydraulic model, which has over 550 miles of water main.  Work included three days of fire flow tests throughout the City and allocation of demands using up-to-date billing and parcel data.  Phase II of the project, the Capital Efficiency Plan™, identified and prioritized areas for improvement within the distribution system.  Our services included evaluating the condition of the existing distribution system infrastructure to determine the adequacy of meeting present and future demands, calculating needed storage requirements, assessing and prioritizing system improvements, reviewing and evaluating typical fire flows throughout the system, creating a pipe asset management rating system, and recommending improvements to the distribution system.

Tata & Howard calibrated the hydraulic model under extended period simulation for an evaluation of the Super High Service Area with the Chester Street Tank off-line due to rehabilitation.  The configuration of the service area included two distinct zones.  The Chester Street Tank is located in one area and the Howland Hill and Apricot Tanks are located in the other area.  To remove the Chester Street Tank from service, an evaluation of supply and pressures needed to be completed.  The results of the analysis included running both zones off the Apricot Tank and utilizing the Chester Street Pump Station to maintain pressures within the vicinity of the Chester Street Tank.

M36 Water Audit, Wayland, MA

Tata & Howard, Inc. was retained by the Town of Wayland, MA (Town) to complete a water audit of the water distribution system based on data and system information for the calendar years 2013, 2014, and 2015.  The project included assessing the amount of lost water using the American Water Works Association M36 water audit methods.  The report estimates the volume of lost water in terms of non-revenue water, identifies potential sources of lost water, and estimates system performance indicators including the Infrastructure Leakage Index.

The AWWA water audit results found that the Town’s non-revenue water was approximately 223 million gallons (mg) in 2013, 80 mg in 2014, and 93 mg in 2015.  The associated annual costs of water lost were approximately $425,000 in 2013, $320,000 in 2014, and $398,000 in 2015. In addition, 64% of the Town’s meters are over 15 years old.   The audit found that many of the losses are a result of customer meter reading and billing procedures.  Recommendations to reduce water loss included the following: volumetrically testing master meters at multiple flow rates and performing a field to database audit of SCADA flow reported from master meters; implementation of a customer meter testing and replacement program; upgrade of the customer billing system or replacement with advanced metering infrastructure (AMI); and documentation of unbilled and unmetered water use with the use of meters whenever possible.

To assist the Town with addressing the customer billing issues and aging meters, Tata & Howard completed a water meter and AMI evaluation. Next steps include assistance with a request for proposal (RFP) for AMI, and assistance during meter installation.

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Water Audit, Grafton, MA

Tata & Howard, Inc. was retained by the Town of Grafton, MA to complete a water audit of the water distribution system based on data and system information for the calendar year 2015.  The project included assessing the amount of lost water using the methodology outlined in AWWA’s Water Audits and Loss Control Programs, Manual of Water Supply Practices – M36, Fourth Edition, published in 2016.  The final report estimates the volume of lost water in terms of non-revenue water, identifies potential sources of lost water, and estimates system performance indicators including the Infrastructure Leakage Index.

The AWWA water audit results found that the Town had total water losses of approximately 182 million gallons in 2015 and the associated annual cost of water lost was over $312,000.  Of this, 11% is Unavoidable Annual Real Losses (UARL). Recommendations to reduce water loss include volumetrically testing master meters and performing a field to database audit of SCADA flow reported from master meters and interconnections, beginning a customer meter testing and replacement program, documenting unbilled and unmetered water use with the use of meters whenever possible, and conducting a third-party review of the leakage detection program. The estimated cost of recommended improvements to the District’s water loss control program was $20,000 for the SCADA audit and leakage detection program review, $129,000 to replace customer meters over 25 years old, and $7,000 in annual costs for establishing master meter and customer meter testing and replacement programs. Implementation of all recommendations would result in an expected ROI of less than one year.

Trinity Avenue Pump Station, Grafton, MA

Tata & Howard is providing engineering services to the Grafton Water District for the Trinity Avenue Pump Station at the Trinity Avenue Wellfield. The project included permitting, design, and bidding of the pump station as well as providing assistance with permitting, design, and reporting to the Massachusetts Department of Environmental Protection (MassDEP) for the proposed Trinity Avenue Well site.  The property was owned by the Massachusetts Division of Fisheries and Wildlife (DFW).  The Grafton Water District swapped land with the DFW to obtain ownership and control of the Trinity Avenue site.  Test wells were installed and short term pump tests were completed on each of the wells.  Based on the results of the tests, it was recommended to install a three well configuration of 18 inch x 12 inch gravel packed wells resulting in approximately 800 gallons per minute (gpm).  The project included an evaluation of alternatives for the access road including installation of a bridge or an open bottomed culvert, and T&H assisted with the preparation of permanent easements for the installation of utilities and roadway to the well site. In addition, T&H prepared and submitted an NOI to the Grafton Conservation Commission. Design included double wythe block and interior concrete painted block with wood truss roof and asphaltic shingles; and security included chain link fence, gates, locks, intrusion alarms, and lighting. T&H also assisted with the coordination of the installation of three phase power to site. Chemical feed at the station includes KOH for pH adjustment and chlorine gas for disinfection. Standby power was included in an outdoor enclosure. The design also included a 24-inch transmission main for 4-log removal. Currently, T&H is providing construction administration and resident observation services.

 

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Ozone Water Treatment Plant in Franklin, MA

Tata & Howard provided design and construction services for a new water treatment facility that houses a 1.2 mgd ultrafiltration system and completed a pilot test that consisted of an evaluation of two separate ultrafiltration technologies.  Franklin Wells No. 1 and 2, located off Hayward Street in Franklin, Massachusetts were installed in the 1940’s with a combined safe yield of 1.2 million gallons per day. Due to high concentrations of iron and manganese in the groundwater, the wells were only used to meet peak water demands during the summer months. The construction of the water treatment facility recaptures the yield from these two sources.  The water treatment facility consists of a main building which houses static mixers, ozone feed equipment, chemical feed equipment, prefilters, membrane filtration equipment, instrumentation and controls. Treatment consists of ozone oxidation followed by membrane ultrafiltration. The project was funded in part by the Massachusetts Water Pollution Abatement Trust through a low interest state revolving fund loan.

The overall treatment scheme is as follows: ozone injection, oxidation of iron and manganese in an ozone contact tank, prefiltration, treatment through two ultrafiltration membrane skids, chlorination prior to a clearwell, and fluoride addition prior to discharge into the distribution system. The plant is designed to recycle backwash water and membrane recirculation water to the head of the plant utilizing two decant tanks. Ozone is produced on site utilizing compressed air, while a LOX tank is available to allow for the production of additional ozone if required in the future.

 

Capital Efficiency Plan™ for Manchester-By-The-Sea, MA

Tata & Howard, Inc. was recently retained by the Town of Manchester-by-the-Sea to complete a Capital Efficiency Plan for the Town’s water system.  The system was evaluated to identify areas of the water distribution system in need of rehabilitation, repair, or replacement, and to prioritize improvements to make the most efficient use of the Town’s capital budget.  The study evaluates the existing water infrastructure including water transmission and distribution piping and appurtenances.  In addition, water storage and supply needs were evaluated and prioritized. The analysis and improvements in this report are based on the Three Circles Approach for optimum capital efficiency, which combines hydraulic and critical component considerations with an asset management rating system to evaluate the condition of the water mains in the distribution system.  Each circle represents a unique set of evaluation criteria for each water main segment.  From each set of criteria, system deficiencies are identified.  System deficiencies from each circle are then compared.  Any deficiency that falls into more than one circle is given higher priority than one that does not.  Using the Three Circle Approach, recommended improvements will result in the most benefit to the system.  In addition, the Three Circle Approach allows us to identify any situations that mitigate a deficiency in one circle and eliminate a deficiency in another circle.  By integrating all three sets of criteria, the infrastructure improvement decision making process and overall capital efficiency are optimized.

Recommendations included a siting study for a second storage tank, Phase I-III distribution system improvements, and the continuance of scheduled maintenance programs such as hydrant flushing, leak detection, and meter testing. The Town’s pavement management plan was also taken into consideration to best prioritize and coordinate utility work with roadway reconstruction.

 

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Capital Efficiency Plan™ and Water Supply Study in Rowley, MA

A Capital Efficiency Plan was completed for the Town of Rowley in May 2017.  The study evaluated the 45 miles of the Town’s water distribution system using the Three Circles Approach, which consists of a system hydraulic evaluation, criticality component assessment, and asset management considerations.  From each set of criteria, system deficiencies were identified and a 20-year recommended improvements plan was provided.  Recommended improvements consisted of water main replacement projects, a pumping capacity evaluation and well redevelopment study, an interconnection analysis, and a distribution static pressure evaluation.

 

Capital Efficiency Plan™ for Avon, MA

Page Street Tank

Tata & Howard recently completed a Capital Efficiency Plan™ for the Town of Avon, MA.  As part of the project, Tata & Howard updated and verified the Town’s existing hydraulic model.  The work included the completion of fire flow tests throughout the Town and allocation of demands using up-to-date billing and parcel data.  The Capital Efficiency Plan™ identified and prioritized areas for improvement within the distribution system.  Our services included evaluating the condition of the existing distribution system infrastructure to determine the adequacy of meeting present and future demands, assessing and prioritizing system improvements, reviewing and evaluating typical fire flows throughout the system, creating a pipe asset management rating system, and recommending improvements to the distribution system. Recommendations included installation of two replacement wells, conducting an interconnection study, rehabilitation of the Page Street Tank, and phased distribution system improvements.

The hydraulic model was also verified under an Extended Period Simulation (EPS), which considers changes in the distribution system over time.  The EPS will be used to evaluate tank operating ranges and modifications to the well operating conditions.