Storage Archives - Tata & Howard

Rehabilitation of a 130 Year Old Tank, Newton, MA

About the System

The water distribution system in the City of Newton, MA (City) serves approximately 90,000 people and includes 319 miles of water main ranging from 2-inches up to 30-inches. There is a southern pressure zone, a northern pressure zone, and three additional high service areas. All water is supplied by Massachusetts Water Resources Authority (MWRA) and the system utilizes two tanks, the Waban Hill Reservoir and the Oak Hill Tank.

Installation of the 24-inch cast iron piping in 1890

The Waban Hill Reservoir (Reservoir) is located in the Chestnut Hill area of Newton and serves the southern pressure zone. The Commonwealth Avenue Pump Station, operated by the MWRA, serves Newton’s southern pressure zone and fills the Reservoir. The Reservoir has a capacity of approximately 10 million gallons (MG) with four chambers that were built in stages: Chamber 1 was constructed in 1891, Chamber 2 in 1901, and Chambers 3 and 4 in 1917. Each chamber is approximately 2.5 MG. At the center of the reservoir is a gate chamber building that houses the influent and effluent valves and piping to each of the chambers as well as the 90-inch diameter central core standpipe.

As shown in Figure 1, there is a 24-inch diameter common inlet/outlet line that fills the interior standpipe and then overflows equally into all four chambers. When drawing, the 24-inch diameter check valve opens and draws through the effluent lines and out the common inlet/outlet. An additional 24-inch diameter inlet/outlet pipe is located in the corner of Chamber 2 that operates Chamber 2 only if needed. During construction, Chamber 2 was used to feed the system through the secondary inlet/outlet pipe while work was completed on the effluent valves for all chambers. During construction, the effluent pipe from Chamber 2 to the core was plugged so that work could be performed on the piping and valve while keeping Chamber 2 in service.

All chambers have a drain line and valve that manifold into a 24-inch diameter drain line that runs under the existing common inlet/outlet pipe. The bottom of the interior standpipe as well as the standpipe overflow both drain into the 24-inch drain line.

Design

The original scope of the repair project included rehabilitating the 90-inch diameter standpipe, replacing four 24-inch effluent valves, and replacing the asphalt shingle roof.

Prior to construction, it was important to review the impacts of removing Chambers 1, 3, and 4 from service on the distribution system. The existing hydraulic model for the City was used to evaluate pressures and available fire flow throughout the system with just Chamber 2 online. The inlet/outlet pipe for Chamber 2 runs down Commonwealth Avenue to the Pump Station (blue line in Figure 2) while the main inlet/outlet pipe from the Central Core runs down Ward Street to the Pump Station (red line in Figure 2). Changing the location of where water enters the system from the Reservoir in turn impacted the hydraulics at certain areas of the system, specifically at higher elevations north of the Reservoir. A recently installed 12-inch diameter interconnection between the two feed lines was opened, reducing the overall headloss in the system.

The design required a contingency plan, addressing potential challenges such as losing the entire Reservoir due to a water main break on the inlet/outlet pipe to Chamber 2. Through close coordination with T&H, the City, and MWRA, an emergency response plan was created that added enhanced scenarios. T&H evaluated the model for the best location of a mobile pumping unit and location of pressure relief valves. The City installed additional hydrants so the City could use MWRA’s mobile pumping unit if needed to pump from the northern pressure zone to the southern pressure zone, which required coordinating availability of equipment with MWRA.

Following a review of the challenges, the design scope was revised. Final design and bidding on the project included standpipe rehabilitation, effluent valve and piping replacement, drain valve replacement, check valve replacement, and asphalt shingle roof replacement as well as the standpipe cover and man-way, interior lighting improvements, and instrumentation.

Construction Challenges

There were many construction challenges to overcome as part of the design. Record drawings indicated an isolation valve was located on the common inlet/outlet pipe; however, the valve was unable to be found. A new valve was installed as a change order for the project.

The construction contractor was limited to light loads due to the uncertainty of the structural integrity of the roof to support specific loads, meaning no cranes or heavy equipment could be used, and spanning a crane from the access road to the gate chamber was cost prohibitive.

The existing valves were embedded in concrete and the flanges were severely deteriorated. Because of the age of the pipe, angles and bolt patterns were not easily matched with modern piping. Therefore, stainless steel piping was used to fabricate the needed angles to connect the new valves to the common inlet/outlet pipe.

The standpipe was showing signs of severe deterioration. Under recommendations from MassTank, specialty repairs were required to prolong the life of the standpipe. Steel plates were installed at the joints within the standpipe, both interior and exterior surfaces were sand blasted, a 200 mil epoxy coating was installed on the interior surfaces, and a 10 mil coating was applied to all exterior surfaces.

Initial filling of the reservoir caused Chamber 2 to fill faster than Chambers 1, 3, and 4 which caused the Commonwealth Ave. Pump Station to shut down. Therefore, the MWRA mobile pumping unit was relocated to the Waban Hill Reservoir and water was pumped from the hatch in Chamber 2 through the hatch in Chamber 1 which was connected to Chamber 3 and 4 through the central core.

Conclusion

Construction was completed in February 2024 and the project was highly successful with minimal service interruption due to a close working partnership with Tata & Howard, the City of Newton (client), and MWRA.

Four Water Storage Tanks, Westfield, MA

Tata & Howard provided engineering services to the City of Westfield for its water tanks, most recently the Provin Tank. For background, the City of Westfield water system consists of 242 miles of water main ranging in size from under 4-inches up to 24-inches and has one main service area. There are also four small high service areas, each of which utilizes a booster pump station. There are nine groundwater supply sources and one active surface water supply source, the Granville Reservoir, and there are interconnections with the City of Springfield at three locations. The system has a total of four tanks with a total capacity of 11.2 million gallons (mg). In 2014, a Condition Assessment Report was completed for each of the City’s four prestressed concrete tanks in order to evaluate condition of each tank and provide recommendations for required rehab work.

The site of the East Mountain Tank, a 2.7 mg tank constructed in 1961, was deemed a “hard hat zone” due to its declining condition. The dome and dome cap were determined to be in fair to poor condition, showing significant deterioration of concrete, and it was further determined that the dome would need to be completely replaced. Due to the significant rehabilitation required, the City decided to construct a new tank. Tata & Howard started the design of the new East Mountain Road Tank in 2017, and the new tank was constructed and operative by 2020.

Wanting to be proactive and avoid the deterioration found at the old East Mountain Road Tank, the City contracted Tata & Howard in 2020 to design and bid the rehab of the City’s three other tanks: the Northwest Road Tank, Sackett Tank, and Provin Mountain Tank.

Rehab work required on the Northwest Road Tank, which was constructed in 1975, consisted of exterior cleaning and coating, repairing of concrete patches, replacing access hatches, replacing the dome vent, and installation of a new overflow screen.

The Sackett Tank, which was more recently constructed in 1991, only required exterior cleaning and coating and replacement of an access hatch.

The Provin Mountain Tank, which is located in the southeastern corner of City, is a 5.0 mg prestressed concrete tank originally constructed in 1967. Measuring 148 feet in diameter and standing 40 feet high, it connects to the system via a 16-inch line. The original scope of the rehab work needed was as follows:

Exterior cleaning and coating
Concrete patch repairs
Injecting a polyurethane grout into a crack
Replace dome hatch and dome vent
Install new overflow screen
Evaluate and repair exposed and broken prestressed wires

With all of these tanks being prestressed concrete, prestressed wires are wrapped tightly around the dome ring as reinforcement to hold the weight of the water. In October 2021, the contractor arrived on site to complete the rehab work on the Provin Mountain Tank. When they started chipping away at loose concrete, it was discovered just how bad the condition of the dome ring was. Each day, more wires were found broken, with more than one third of the total wires found to be broken. The dome was in danger of potential collapse.

The team reconvened to discuss next steps on the project. During rehab work, the contractor surveyed the surrounding area to see if any residents were potentially in the path of the tank if it were to collapse. The tank level was lowered to about 25% capacity, and it was decided to complete repairs on the tank to act as a temporary fix. Temporary repair work began in October 2021 and was completed in April 2022, consisting of the following:

Remove all loose gunite material and broken wire by hand
Apply shotcrete to the dome ring face and provide a uniform surface
Install prestressing strand, Teflon shims, and anchors
Apply shotcrete to fully encapsulate the prestressing strand
Repeat for subsequent layers (estimate 3-4 layers, 17 strands total, 0.6 inch each)
Pressure-wash top surface and face of dome ring
Seal surface cracks on the top surface of the dome ring with Sika 55
Apply a waterproof coating on the dome ring apron and face (Tamoseal)

This repair work extended the useful life of the tank by 2-5 years. The question then was whether to abandon the existing tank or replace it with a new tank. To evaluate if a replacement tank was needed, a storage evaluation was completed. US Census trends and ASR data used to estimate service populations and demands to 2041 showed that the future MDD was estimated at 10.7 mgd. Emergency storage, equalization storage, and fire flow storage were calculated and totaled for current and future demand conditions, showing that the future required storage for the system was approximately 2.77 mg. While having a water storage surplus may initially sound like a positive, too much of a surplus can lead to water quality issues such as water age and disinfection byproducts. This data indicated a replacement tank was not needed based on needed system storage alone.

Hydraulic impact was also studied. Pressure decreased 2-4 PSI depending on which sources were running, and the available fire flow decreased up to 600 gpm, but was limited to the area around the tank which is mostly residential. Resultant flows were sufficient for the residential area.

While storage and hydraulics showed that the tank was not needed, it was determined that there would be significant lack of fire protection in much of the system if the Sackett Tank was offline for repairs or other issues in addition to elimination of the Provin Mountain Tank. Due to the lack of fire protection under this scenario, it was ultimately recommended to replace the tank.

EPS modeling was used to evaluate change in water age for various size replacements. It was ultimately decided to construct a 2 mg tank with the recommendation that the City change the operation of their wells to increase fluctuation in tank levels. Overflow was decided to match the old tank at 428 feet, and the inside diameter of the new tank would be 79 feet compared to 148 feet of the existing tank. The new Provin Tank is currently in design with an anticipated bid this fall, with site work expected to begin by late fall. Given that temporary repairs were completed in April 2022, we are on track to replace the tank within the 2-3 year time frame based on the lifespan of the temporary repairs.

The existing tank will be demolished after the new tank is in service.

East Mountain Road Water Storage Tank, Westfield, MA

Tata & Howard was contracted to provide design, bidding services, construction administration, and resident observation for the new water storage tank on East Mountain Road in Westfield, MA. The project included subconsultant work for the development of a survey, borings work, geotechnical evaluation and report, and environmental services to prepare a Habitat Assessment and MESA Checklist.

The design phase of the project consisted of the following:

Development of a site plan showing the proposed 2.1 MG precast, pre-stressed, wire-wound concrete tank location
New 16-inch diameter water main
Removal of the existing 16-inch AC water main
Access road improvements.

The new tank and access road required a Stormwater Management Permit to be filed with the City Engineering Department. Permits were filed with MassDEP, FAA, and MESA.

The construction administration phase consisted of the following:

Attending progress meetings with the client
Providing consultation on construction matters
Contracting with a qualified biologist to develop and supervise implementation of the Rare Vertebrate Protection Plan
Review and approval of shop drawings, schedules, and other data
Final observations of project
Finished set of record drawings

The resident project representative phase included the services of a part-time Resident Project Representative at the site to assist in the observation of the work.

The precast concrete tank, constructed by DN Tanks, is made of multiple concrete panels that were cast on site and lifted into place by a crane.

The new 2.1 mg tank will replace the city’s original 2.7 mg tank and is now online.

Auburn, MA Water Storage Tank

Tata & Howard was contracted to provide Design, Construction Administration, and Resident Project Representation services for the construction of the Prospect Street Water Storage Tank in Auburn, MA.

The project consists of the construction of a 1.0-million-gallon capacity glass-fused-to-steel water storage tank with associated piping and appurtenances, electrical work, a tank mixing system, and site work. Other work included the decommissioning and demolition of the pre-existing 500,000-gallon capacity welded steel water storage tank at the site.

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.

Worcester, MA Hydraulic Modeling 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.

Water Distribution System Evaluation and Tank Design, Paxton, MA

The new tank was completed in 2015 — The new tank was completed in 2016.

Town of Paxton, MA

Tata & Howard provided engineering services for a comprehensive water distribution system evaluation and study. The work included development of a hydraulic model using WaterCad software. The plan included fire flow tests, review of the water supply agreement with the City of Worcester, preparation of projected water demands based on historical use and population trends, and evaluation of storage. The plan also included an evaluation of potential water supply sources within Town boundaries.

This project included an evaluation of the system prior to design of the tank to determine the best solution. Work included calibrating the model under extended period simulation (EPS). The hydraulic model was used to determine the best hydraulic gradeline elevation of the system to reduce the storage surplus. Additionally, the model was used to track the chlorine residual from the Worcester Pump Station to the extremities. Jar testing was completed to determine the chlorine demand in the water supply while water quality testing results assisted with determining the chlorine demand in the piping system. The model was used to simulate the chlorine degradation. Improvements were input into the hydraulic model and the effects on the chlorine residual in the extremities reported. Improvements such as an elevated tank at Maple Street with a total usable volume, reduction in hydraulic gradeline elevation, and cleaning and lining water mains were evaluated. The analysis determined that a new tank at Maple Street is necessary based on water quality and cost.

Tata & Howard provided assistance with the preparation and submittal of a Project Evaluation Form to the Massachusetts Department of Environmental Protection for the construction of a new elevated tank with a capacity of 0.2 million gallons. The new tank reduced the water age in the system by replacing the deteriorating ground level tank. Tata & Howard provided construction administration and resident observation services for the new tank, which was completed in 2016.

Whitepaper:

ABSTRACT: In 2012, the Town of Paxton, MA was experiencing significantly reduced chlorine residuals in the extremities of the system along with an aging water tank that required extensive rehabilitation. As a result, the Paxton Department of Public Works (DPW) determined the need to create an extended period simulation (EPS) hydraulic model to evaluate the water age and water quality in the distribution system. The study examined the residual chlorine concentrations and water age throughout the distribution system and presented various options to help mitigate these issues, including replacing the aging tank and adding a chlorine booster pump station at the existing site. Construction of the new tank and pump station was completed in the summer of 2016. Read the complete whitepaper by clicking below:

To download “Town of Paxton, Massachusetts Distribution System Evaluation and Improvements” whitepaper instantly, simply fill out the form below:

Water Storage Tank Replacement, Hamden, CT

Tata & Howard provided evaluation, design, construction administration, and resident observation services to the South Central Connecticut Regional Water Authority (SCCRWA) for the replacement of the Whitney-Wintergreen water storage tank. The project included an analysis of SCCRWA’s Whitney-Wintergreen service area to determine the appropriate volume of storage needed to serve its customers, and a 1 million gallon concrete tank was constructed to replace the existing 1.5 million gallon steel tank at the same site. The project also included demolition of the existing tank as well as stormwater management at the site. The project was completed in September of 2015.

Water System Upgrades including Manganese Removal, Montgomery, VT

Tata & Howard designed and constructed the improvements to eliminate low and inadequate system pressures, construct a new source, pilot test filtration for manganese removal, design and construct required distribution system piping to connect the plant and storage tank with the system, design a new concrete storage tank, booster pump stations, and the filtration facility for manganese removal. The project was very successful and remains in great condition today.

Water System Improvements and Funding Assistance, VT

Greensboro Fire District No. 1 (GFD#1), situated on the Northern portion of the Green Mountains in Vermont, requested assistance with their water distribution and treatment systems due to deficiencies identified in a sanitary survey conducted by the State of Vermont. This contract addresses these deficiencies and provides the District a more robust covered water storage tank, secure buildings that house controls and chemicals and related equipment, emergency power generation, and water metering.

As part of the project, Tata & Howard helped GFD#1 secure funding that included a 45% USDA Grant for the originally planned project with an estimated budget of $2,900,000. During the design phase, the District lost their primary well source due to an extended drought. Tata & Howard engineers worked with the District to secure a 100% USDA grant for the cost of constructing a new municipal well source and associated emergency generator and related appurtenances.

Tata & Howard provided design, construction administration, and resident observation for the water system improvements project. Construction began in the spring of 2015 with the setup of a temporary water storage system and demolition of the existing water storage tank roof structure. Precast planks and a ballasted membrane roof were then installed, providing safe, quality water. Two new small buildings were constructed to house chemicals and water well piping and controls, along with an emergency generator to provide continuous water in case of interruption to electrical power.

Services: Storage