Hemlocks Raw Water Pumping Station

Aquarion Water Company Pump Station Improvements

Hemlocks Pumps
BEFORE improvements to the Hemlocks Pumping Station.

Tata & Howard provided engineering services for design, bidding, construction administration, and resident observation to Aquarion Water Company for improvements to their existing Hemlocks Raw Water Pumping Station in Fairfield, CT. The project included refurbishing five 300 hp centrifugal pumps and motors, replacing the existing variable frequency drives (VFDs), installing new piping, check valves, and strainers for each pump.

As this facility is a source of supply for Aquarion’s Main System, it needed to be kept operational throughout the construction. The sequence of work required a single pump to be taken off line; refurbished; reinstalled with new piping, VFD, and appurtenances; tested and placed back into service prior to the next pump being taken off line.

Hemlock Pumps
AFTER improvements to the Hemlocks Pumping Station.

Another important aspect of the project was to replace the existing strainers so that they were easier for the plant operators to clean as they get clogged with eels. To simplify maintenance, new stainless steel wye strainers with bottom access to the screens were installed on the suction side of each pump.

Chamberlain Highway Receives New Water Main Connections

The Chamberlain Highway in Meridan, Connecticut has 536 linear feet of new 16-inch ductile iron main and two new fire hydrants. After Tata & Howard completed several test pits to verify connection locations at each end of the new main, construction work started on May 3, 2018 with the installation of a 16” x 16” tapping sleeve and valve at the north end of the project. This existing water main at the north end connection was originally installed in 1894.

Chamberlain West MainWork progressed south until the new main was approximately 50 feet away from the other connection point in West Main Street. Connections to the existing main in West Main Street was performed over a 36-hour period due to the complexity and amount of utilities around the service connection, including a live 24-inch water main five feet away and multiple telephone conduits located 6 inches above the replaced main. Tata & Howard personnel on site at all times to observe that work was in performed in accordance to the plans and specifications.

Following the completion of the Chamberlain Highway water infrastructure improvement project, work to replace two water mains on the state-owned bridge crossing Sodom Brook in Meridan will begin.

UMASS Amherst Hydraulic Modeling

Tata & Howard developed an extensive hydraulic model of the University of Massachusetts (UMass) Amherst campus. The model was verified under steady state and an extended period simulation (EPS) was completed.  Tata & Howard conducted a hydraulic review and criticality assessment and used the results to make improvement recommendations.  Tata & Howard also identified water distribution system sustainability projects for the irrigation, cooling tower makeup, and toilet flushing water.

This project included a supplemental water supply system analysis.  Potential ground and surface water sources on campus, including existing and potentially new stormwater retention ponds, were evaluated for process and irrigation water.  In addition, Tata & Howard created a hydraulic model of the UMass reclaimed water system.

The study also examined the effects that the proposed system improvements and interconnections would have on water quality.

A Decade of Infrastructure Improvements

Wiscasset Completes Capital Efficiency Plan™ Infrastructure Improvements

The Wiscasset Water District (WWD) completed its final phase of water main replacements for the Town of Wiscasset, ME. In 2007, Wiscasset, a rural coastal town in Maine, embarked on a long-awaited infrastructure improvement program to replace the Town’s century-old waterlines. The Wiscasset Water District, engaged Tata & Howard’s services in 2010, to prepare a Capital Efficiency Plan™ (CEP), to identify areas to the Town’s water distribution system needing rehabilitation, repair, and/or replacement.

CEP reportThe Capital Efficiency Plan™ report which included hydraulic modeling, system criticality, and an asset management plan, provided the Utility with a database and Geographic Information System (GIS) representation for each pipe segment within their underground piping system. The CEP report also prioritized the water distribution system piping improvements and provided estimated costs to replace or rehabilitate the water mains.

Wiscasset Main StreetIn response to the CEP™ findings, the Wiscasset Water District retained the services of Tata & Howard, to perform design, bidding, construction administration, and resident project representation services for a series of water main projects.

Phased over 10 years, the plan included replacing 33,150 feet of 12-inch and 8-inch piping, installation of a water storage tank mixer, SCADA upgrades, and office landscaping improvements.

The final phase of water main replacements is scheduled to be completed during the summer of 2018 and will fulfill all the Priority I water main improvements identified in the 2010 CEP™ report. The projects were funded in part by a combination of USDA Rural Development grants (6 total) and loans (7 total), as well as coordination with the Maine Department of Transportation and Rural Development.

With the water main improvements nearing completion, the Wiscasset Water District has retained Tata & Howard to reevaluate its 2010 Capital Efficiency Plan™. The revised plan will update the water main inventory database and review additional recommended water distribution improvements.

Unidirectional Flushing Program, Wayland, MA

Wayland Zone MapTata & Howard prepared a sequential Unidirectional Flushing Plan (UDF) for the Town of Wayland’s water distribution system, utilizing the existing hydraulic model to develop flushing sequences for hydrants and valves to be operated.  The sequences were updated from the original plan to review anticipated flushing velocities and identify areas of potential low-pressure concerns. Field assistance was provided during the implementation of the updated plan. A summary report was provided, identifying the amount of water used during flushing, areas of hydrant or valve mapping discrepancies, and areas with broken or inoperable hydrants and valves.

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.