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.
CLIENT: City of Meriden, CT
PROJECT: Fosters Pond Dam Reconstruction
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 provided engineering services to the University of Southern Maine related to the interior and exterior rehabilitation of a welded steel water storage tank. The standpipe was constructed in the 1950’s and is approximately 30 feet in diameter and 105 feet tall with a capacity of 0.55 million gallons. The scope of services included preparing Contract Documents for the cleaning, interior abrasive blasting, exterior pressure washing, and interior and exterior coating application.
The project also included coordination with two cellular companies and incorporation of corresponding design considerations into the Contract Documents. Additional design considerations included providing the USM logo on the tank exterior, repairing foundation cracks and gaps, extending the overflow pipe and installing a flapper, screen, and concrete splash pad, providing safety climb system for exterior access ladder, replacing the roof vent, and installing a new roof access hatch. Tata & Howard provided bid assistance, construction administration services, and full time construction observation. Since the standpipe is located on a college campus, the time frame for completion was limited to summer break, but the standpipe rehabilitation project was completed within budget and on schedule.
Tata & Howard prepared a wastewater treatment and disposal alternative analysis for the Town of Ayer. The analysis evaluated alternative plans for treatment and disposal of wastewater utilizing the Town’s existing wastewater treatment facility, a proposed regional wastewater treatment facility, or a combination of both facilities.
The alternative analysis estimated the wastewater flows and loadings, assessed the condition and capacity of the existing plant unit processes, and recommended improvements to meet the future service needs over the next 20 years. Tata & Howard designed upgrades to the existing main wastewater pump station which pumps the entire volume of wastewater generated in Ayer.
In addition to the overall rehabilitation of the pump station, Tata & Howard designed the addition of new pumping facilities to divert wastewater to the nearby regional wastewater treatment facility at the former Fort Devens, now managed by Mass Development. The main wastewater pump station has a peak capacity of 4.0 mgd and includes four wastewater pumps with a capacity of 2,800 gpm. The upgrades included new variable frequency drives for the pumps and new SCADA.
Tata & Howard has been working with the Town of Hopedale, Massachusetts for a number of years on a variety of wastewater collection and treatment projects. When the Town received an administrative order to address copper and ammonia violations at the plant, they turned to Tata & Howard for assistance. We completed the design and construction of a Wastewater Treatment Facility Upgrade project which included the installation of an automated soda ash feed system and an integrated fixed film activated sludge system (IFAS). The IFAS system is an innovative biological treatment process using thousands of special carriers designed to increase total surface area for biofilm growth without expanding the plant’s footprint. The blowers were also modified to provide better control over the aeration process.
A pilot study was conducted to test the ability of various reagents to facilitate the removal of copper from the waste stream. An automated chemical addition system was designed to improve coagulation. Additionally, a dynamic tangential filter was incorporated into the upgrade project. These improvements have allowed the Town to now meet its discharge limits for ammonia and copper.
