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
The Fosters Pond Dam reconstruction project presented several challenges. The existing spillway was inadequate to discharge the 100-year spillway design flood, and the existing dam was in extremely poor condition. The embankments lacked erosion protection and were very steep, the crest was narrow, and the outlet had fallen into disrepair, rendering it inoperable. Therefore, it was imperative that the reconstruction design of Fosters Pond Dam be designed to improve both safety and reliability, provide a functional and operable outlet, and provide ease of maintenance.
The reconstruction included the construction of new and higher reinforced concrete spillway training walls, upstream riprap erosion protection, a new reinforced concrete gate structure with 24″ inlet and outlet pipes and sluice gate, widened embankment crests to 12′, flattened slopes for ease of maintenance, and a gravel road to allow access to the embankment and gate structure. Riprap erosion protection is now provided on the upstream slopes as well as in the discharge channel. Because of these improvements, the dam can safely pass the 100-year spillway design flood with over a foot of freeboard. The length and level of the spillway weir remains unchanged.
Saugatuck Dam is a concrete water supply dam in Weston, CT built in 1940, now owned by Aquarion Water Company. The majority of this project included repairs and modification to the gatehouse and gate chambers at the dam. Repairs included rebuilding the gatehouse walls, cleaning and painting the intake and outlet valves, and removing and replacing the stems and valve operators. Modifications included installing platforms made of steel beams and fiberglass in the gate chambers to provide safer access the valves in the chambers, and the interconnection of the 36” supply main and the 48” diversion main at the toe of the dam to provide greater flexibility for releasing water from the reservoir.
The Shangri La Ranch water supply, located in New River, Arizona, exceeded the running annual average maximum contaminant level (MCL) for arsenic. For the first quarter of 2015, the running annual average (RAA) was 0.0107 mg/L, and the RAA for the second quarter of 2015 was 0.0106 mg/L. The MCL for arsenic is 0.01 mg/L. Arsenic contamination within aquifers is not uncommon and is generally from natural mineral deposits. Arsenic in high enough concentrations can result in skin legions and damage to the circulatory system and cancer; therefore, it is important to monitor and minimize this contaminant from drinking water.
The Shangri La Ranch is a non-transient, non-community water system that services approximately 240 customers. The actual number of customers served varies and is dependent on the number of people that are visiting the resort during a given period of time. Tata & Howard prepared an Arsenic Treatment Report for the Arizona Department of Environmental Quality (ADEQ) to address arsenic levels in the Shangri La Ranch’s water supply. It included a summary of the existing layout and operation of the water supply wells, representative treatment provided, and recommendations for additional treatment to meet the State and Federal MCL for arsenic.
The results of the study indicated that the arsenic concentrations in Well No. 1 was low enough that blending from the existing wells would adequately reduce the arsenic concentration to below the MCL. It was also recommended that the system install two ISOLUX® cartridges, in parallel, to reduce the arsenic level in Well No. 4 to levels below the MCL prior to blending with the remaining water supplies. ISOLUX® utilizes a zirconium adsorption system to remove arsenic from water
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.
THE CHALLENGE: The existing spillway is inadequate to discharge the 100-year spillway design flood, and the existing, aging dam is in very poor condition. The embankments are steep and lack erosion protection, the crest is narrow, and the outlet is in disrepair and inoperable. The reconstruction of Fosters Pond Dam needs to be designed to improve the safety and reliability of the structure, provide an operable outlet, and make the structure easier to maintain.
THE SOLUTION: The reconstruction includes constructing new, higher reinforced concrete spillway training walls, providing upstream riprap erosion protection, constructing a new reinforced concrete gate structure with 24-inch inlet and outlet pipes and sluice gate, widening the embankment crests to 12 feet, flattening the slopes for ease of maintenance, and providing a gravel road to allow access to the left (looking downstream) embankment and gate structure. Riprap erosion protection will be provided on the upstream slopes and in the discharge channel. With these improvements, the dam will be able to safely pass the 100-year spillway design flood with 1.1 feet of freeboard. The level and length of the spillway weir will remain unchanged.
Tata & Howard was contracted to design approximately 2,000 linear feet of new 12-inch diameter ductile iron water main on Congress Street and West Fountain Street (High Service Area). The work included borings, survey, preparation of plans and specifications, and bidding. Construction of the High Service Area Water Mains took place over the summer, and was recently completed. Tata & Howard provided construction administration and resident observation services.
In addition, Tata & Howard was contracted to design approximately 2,400 linear feet of new 12-inch diameter ductile iron water main on East Main Street (Route 16). The work included survey, wetlands delineation, MassDOT permitting, completion of a Notice of Intent, preparation of plans and specifications, bidding, construction administration, and resident observation services.
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