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:
The Whitin Wellfield Water Treatment Facility design consisted of a pressure filtration vessel housed within a new pre-fabricated metal building, and upgrades to the chemical feed system housed within an existing building on site. The project also included associated electrical and instrumentation, as well as site stormwater management.
The design called for replacement of the existing paved driveway, but since no new impervious pavement was added, the only stormwater runoff that required treatment was the rooftop runoff from the new building. MassDEP guidelines require treatment of runoff from metal roofed buildings within the Zone II radius of a wellfield.
The necessary treatment was achieved by discharging the roof runoff into a grass-lined channel. The grass-lined channel provided pre-treatment for a bioretention area, which consisted of a shallow excavation in which specially selected metal-resistant grasses and shrubs were planted within a specific soil to provide treatment. This treatment train provided the necessary total suspended solids removal but did not receive credit for infiltration, which was required by MassDEP. The biofiltration area was designed to collect, store, and infiltrate a 100-year storm event, so although the BMP train did not receive credit by MassDEP standards, the local Conservation Commission agreed that runoff would be infiltrated and therefore approved the design.
Tata & Howard completed a Water/Wastewater and Related Departmental Organizational Plan for the City of Westfield. Prior to the start of work, the organization included a Water Resources Superintendent, a Wastewater Superintendent, and other department heads to provide water, wastewater, stormwater, and highway services. The chief project goal was to seek alignment of people, business processes, and technology.
Tata & Howard reviewed relevant documents, facilitated individual interviews with knowledgeable managers and staff, and conducted on-site workshops as appropriate to evaluate the City’s current organization against desired business goals and industry best practices. We recommended a revised organization to the City which is in the process of being approved through the City Council. Upon acceptance of the new organization, a detailed report will be submitted.
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.
The Means Brook Reservoir Dam is a concrete gravity dam that was constructed on rock in 1916 in Shelton, Connecticut. The aging dam required repairs in to improve reliability and safety, modernization and rehabilitation of the gate chambers, and replacement of the deteriorated upstream and downstream faces of the dam and the crest, which were severely spalled and delaminated. Hydraulic, hydrologic, and structural studies had indicated that the dam would be overtopped by about 3.9 feet by the Probable Maximum Flood, and that the dam did not have sufficient stability factors of safety for this extreme loading condition. The dam reportedly overtopped by about four inches during the 1955 flood. In 1977, modifications were made to the dam including extension of the spillway to its current length of 100 feet, and construction of a 2.1-foot high concrete parapet wall along the upstream crest of the dam.
Means Brook Dam after rehabilitation, August 2015
Tata & Howard provided design and construction administration for the rehabilitation of the dam that included the following:
Concrete repairs to the crest and both faces of the dam:
Deteriorated and delaminated shotcrete and concrete removed to sound concrete;
Anchor dowels and reinforcing installed, and new concrete surfaces poured;
Upstream face was resurfaced to a depth of about six feet below spillway, and the downstream face to two feet below grade;
New concrete surface designed with a nominal thickness of 12 inches on the downstream face and six inches on the upstream face.
Installation of rock anchors post-tensioned in holes drilled through the dam into the rock foundation to improve stability and provide adequate factors of safety for overtopping by the Probable Maximum Flood.
Removal and replacement of one section of the spillway training wall, and removal and resurfacing of concrete on remaining walls.
Repairs and improvements to the gatehouse and chambers:
Reshingling of gatehouse roof;
New steel plate exterior door for additional security;
Blocking up the existing windows;
Replacement of antiquated electrical system;
Replacement of both of the inoperable sluice gates and their appurtenances in the upstream gate chamber;
Replacement of the former vertical brass ladders in the intake gate chambers with new fiberglass ladders, including a base for fall protection and retrieval system;
Replacement of wooden stairs in the lower gatehouse with new aluminum ships ladder;
Replacement of the pneumatically operated butterfly valve on the 30-inch service main in the basement of the lower gatehouse with an electrically operated butterfly valve that can be remotely controlled;
Installation of an extension stem and electric operator;
Replacement of the 8-inch chamber drain and 10-inch auxiliary outlet gate valves;
Replacement of wooden hatches over floor openings within the gatehouse with aluminum grating with cover plates;
Installation of chain link fence along portions of the spillway training wall for safety; and at both ends of the dam for security;
Installation of galvanized steel pipe railings along the upstream and downstream crest of the dam for safety; steel pipe rails were chosen for the dam crest instead of chain link fence because the dam crest is subject to overtopping.
The project received a 2017 Excellence in Engineering Merit Award from the American Council of Engineering Companies, Connecticut. Read more here.
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.
Milford Water Company retained Tata & Howard to perform a visual inspection and prepare a report of conditions for Echo Lake Dam and appurtenant structures. Echo Lake Dam is located at the head of the Charles River in Hopkinton, Massachusetts, and serves to impound water to create Echo Lake, a public water supply reservoir for the Town of Milford, operated by the Milford Water Company.
The dam measures approximately 198 feet in length with a structural height of 41 feet and a hydraulic height of 30 feet from the 24-inch outlet pipe to spillway crest. The dam was built in 1898, raised 10 feet with stone masonry in 1901, and raised 2.5 feet with stop planks in 1987. The dam is classified as large and high hazard potential.
The Phase I Inspection / Evaluation Report was performed in accordance with MGL Chapter 253, Sections 44-50 of the Massachusetts General Laws. The purpose of the investigation was to inspect and evaluate the present condition of the dam and appurtenant structures to provide information that will assist in both prioritizing dam repair needs and planning/conducting maintenance and operation.
The investigation was divided into four parts: 1) obtain and review available reports, investigations, and data previously submitted to the owner pertaining to the dam and appurtenant structures; 2) perform a visual inspection of the site; 3) evaluate the status of an emergency action plan for the site and; 4) prepare and submit a final report presenting the evaluation of the structure, including recommendations and remedial actions, and opinion of probable costs.
Tata & Howard has been conducting Infiltration/Inflow (I/I) investigations for The Town of Milford, Massachusetts for the past several years within their collection system, which consists of approximately 90 miles of 4-inch diameter to 36-inch diameter gravity sewers and force main, ten pump stations and a 4.3 million gallon per day (MGD) advanced wastewater treatment facility. Throughout the investigations, I/I sources such as broken service connections, broken pipes, cracks, roots, and illegal connections have been identified. The I/I ranged from 144 gallons per day (gpd) to in excess of 400,000 gpd. Based on the results of previous I/I investigations, the Sewer Department was able to remove a direct connection from the street drainage system to the sewer system that resulted in the removal of an estimated 450,000 gpd of extraneous water from the sewer system, therefore regaining 10 percent of available capacity at the treatment facility.
As a result of conducting these I/I investigations, the Town has the ability significantly reduce the amount of extraneous water entering the collection system, as well as free up capacity at the treatment facility. The Town of Milford has also incorporated a 5:1 removal policy within the Town Bylaws, which requires Contractors/Builders to remove 5 gpd of I/I from the system for each gallon of wastewater proposed to be discharged, which minimizes repair costs for the Town and their residents.
Baldwins Pond Dam is a stone masonry and earthen embankment dam located on Harbor Brook just upstream of Westfield Road. The dam has a length of about 200 feet and a maximum height of about 17 feet. A concrete gate chamber at the right (looking downstream) end of the spillway provides controls for the 30-inch low level outlet, which discharges through the right training wall. Access to the operator is provided through a hatch in the top of the chamber. The spillway has an overflow length of 85 feet and a stepped concrete apron at the downstream toe. The upstream embankment slope and the area downstream of the apron are protected with riprap. Baldwins Pond has a surface area of 6 acres and a tributary watershed of 8.34 square miles.
The dam was rehabilitated in 1998, designed by Tata & Howard’s Waterbury, CT office.
The exposed water main ran under the bridge on Mechanic Street
Tata & Howard provided engineering consulting services to the Town of Monson, Massachusetts for the relocation of the 8-inch diameter water main on Mechanic Street.
The main was originally constructed in 1897 under the streambed; however, after 117 years in this location, the decrease in surface water elevation had exposed the water main. The water level averaged about one inch below the top of pipe, exposing the top portion of the entire section of main that crossed the brook, approximately 15 linear feet of main. Exposure of the water main made it susceptible to freezing during the winter months, which could have resulted in a break and subsequent lost water or contamination from the brook to the Town’s entire water system, potentially resulting in significant costs to residents and to repair, clean, and disinfect the system. The main provides potable water to approximately fifty residents. There were only two gate valves located at the ends of Mechanic Street. As a result, if the main were to fail at the bridge, the entire street would have to be shut down in order to repair the damage, disrupting water service for the 50 serviced residents.
The Mechanic Street Bridge has a history of failure. As a result of a major flood event in 1955, the bridge failed and was completely replaced in 1956. The bridge ran directly over the water main, which posed an additional threat to the main should the failure reoccur. Although the main was unaffected during the previous failure, its weakened condition made it more susceptible to failure in a similar event.
Tata & Howard provided funding assistance and the project qualified for and received a FEMA Hazard Mitigation Grant for 75% of the cost of the project. The work included the preparation of design plans and specifications for the relocation of the 8-inch water main to a self-supporting beam structure attached to the bridge abutments on Mechanic Street. The project also included bidding, permitting, construction administration, and resident observation.
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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.
