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.
Tata & Howard assisted Maine Water Company with mechanical, structural, and architectural design of a new high service zone booster pump station on Barra Road within the Biddeford-Saco water distribution system. The new pump station replaced the existing Alfred Road station, providing pumping capacity to meet current demands in a majority of the City of Biddeford as well as room for future expansion. Funding for the project was provided in part by the Maine Drinking Water Program State Revolving Fund (DWSRF).
Mechanical design for the project consisted of sizing and selection of three (3) centrifugal booster pumps, associated piping, and appurtenances. The pumps were sized with input from a hydraulic model of the system developed by Tata & Howard, and they were selected to maximize the available flow from a 16” cast iron pipe line that crosses the Maine Turnpike from the water system’s major storage reservoir. A pipe gallery was incorporated into the slab and foundation design as well as insulated concrete form (ICF) foundation walls. Per the Owner’s request, the architectural design used colors and materials similar to the other buildings within the surrounding commercial office park. Also, a gable roof canopy was added to the design (pictured below) to help shield the emergency backup generator from the elements. Precautions were taken to ensure proper air flow and ventilation was achieved to meet the requirements of the generator. Construction of the pump station was completed in 2015.
Tata & Howard provided the design of a 1.44 million gallon per day (mgd) water treatment plant to treat water from the Whitinsville Water Company’s Whitin Wellfield. The existing facilities consisted of a chemical injection facility and pump station, and historical high levels of iron and manganese led to water discoloration issues in the distribution system.
The new treatment facility for the Whitin Wellfield utilizes chlorine oxidation and GreensandPlus™ media filtration to remove iron and manganese from the raw water to concentrations below Secondary Maximum Contaminant Levels. The installation of 16-inch pipe between the existing facility and the water treatment facility is utilized in combination with filtration to provide contact time to achieve log removal of Giardia Lamblia (Giardia), Cryptosporidium, and viruses, if it becomes necessary in the future.
The treatment plant components include a three cell horizontal pressure filter vessel, a backwash water tank, and backwash pumping systems. The design also included a dehumidification system and the installation of crushed stone below the filter vessel and spent backwash tank. This allows for water to infiltrate into the ground and prevent puddling on the concrete floor in the event that condensation does occur on the equipment.
Tata & Howard’s Waterbury, CT office completed forty (40) dam inspections and reports for the Department of Energy and Environmental Protection (DEEP) for dams located in the Western District of Connecticut, including fifteen flood control dams. The dams were rated from a hazard classification of ‘C’ to ‘BB’, and were located in urban environments, suburban locations, and rural settings. The construction of the dams varied from earthen embankments to mortared stone masonry to concrete to roller compacted concrete. The spillways varied as well, including ogee spillways, broad crested weirs, intake risers, and a drop inlet structure.
Bunnells Pond Dam
Each report included a description of the dam, inspection checklists, photographs, a sketch of the dam identifying the major features and showing the photo locations, an aerial photograph and location plan, and recommendations for improvements.
T&H staff also provided the DEEP with a cost estimate for the recommended repairs and maintenance at the 23 non-flood control dams, including contingencies for engineering services, permitting, and construction administration support services.
THE CHALLENGE: Skilton Road Bridge was originally built in 1865 as a one lane, dry stone masonry arch bridge over the Skilton Gorge in Watertown, Connecticut. Rehabilitation in 1988 included strengthening of the stone masonry with reinforced concrete, and adding concrete guide rails to the bridge. On December 10, 1991, Skilton Road Bridge was added to the National List of Historic Places, and in 2013, the bridge was found to be structurally deficient.
Before rehabilitation
THE SOLUTION: Tata & Howard’s design for the rehabilitation and repair of the bridge required careful consideration of the historical nature of the structure. The design was approved and construction took place in 2015. All structural deficiencies were addressed and the project included the following:
Removed existing guide rails
Installed prestressed concrete beams across the top of the existing bridge
Widened the bridge for two 9’ travel lanes and a sidewalk
Installed new aluminum bridge rails covered with wood
Repaired the stone masonry on the west abutment wall
Added new storm drainage
After rehabilitation
PROGRESS: Construction on the Skilton Road Bridge was completed in October of 2015, and a ribbon cutting ceremony was held on December 10, 2015. The bridge maintains its historic integrity.
A ribbon cutting ceremony was held December 10, 2015
Let's stay in touch.
Get the latest news, blogs, and insights conveniently in your inbox.
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.
