Water Tank Services
CEI's water tank services include:
Inspection Using sUAS (drones)
CEI Working With the Dennis Water District
Water Storage Tank Evaluation
Located on Route 28 in Dennis, MA, this water storage tank is a 500,000 gallon elevated water storage tank constructed in 1955 by Pittsburgh Des Moines Steel Company. The overflow of the tank is approximately 170 feet above ground. The inspection showed that the tank required extensive repairs, abrasive blasting and complete re-coating. The tank is located in close proximity to structures on neighboring properties including the Dennis Fire Station and homes. Rehabilitation work needed would include complete Class 1A containment, repairs to various components (including but not limited to sway rods, radial rods, vent, hatches), cleaning of tank interior and pit filling, abrasive blast cleaning and painting of tank exterior. It was determined that the cost to rehabilitate the tank would not be cost effective given the age of the tank. Therefore, the District opted to evaluate replacement of this tank in lieu of the costly rehabilitation work.
New Tank Design & Construction
CEI completed the evaluation, planning, design, permitting, bid and construction phase for a new 1 MG elevated composite water storage tank. As an initial step, CEI evaluated potential tank locations and sizes, accounting for hydraulics, future water demands, available properties and aesthetics. Work included estimation of future water demands and the development of a hydraulic computer model of the distribution system using WaterGEMs to evaluate the effects of various tank sizes and locations. Based on the supply provided by existing tanks and anticipated future demands, it was determined that the existing tank would most effectively be replaced with a 1 MG elevated tank.
Two potential tank sites were evaluated, the existing site and an alternate location nearby. Using the model, the effects of each on system pressures, available flow and water age were compared for the average week, maximum week and emergency flow (fire flow and main break) conditions. The results showed that a tank located at either site would provide comparable hydraulic benefits. This is primarily due to the robust distribution main looping throughout the system. Since the tank sites performed comparably based on hydraulics, additional factors were evaluated including community opinion, property ownership and size, revenue from cellular service providers and costs. The capital and operation and maintenance cost for a tank at either site would be nearly equivalent since the sites are located at similar ground elevation and would therefore require a similar height tank. The more influential deciding factor is the revenue from cellular service providers. The existing Route 28 Tank generates annual revenue from cellular service providers. A tank at the alternate site may not be suitable for the cellular equipment and at a minimum would require construction of related infrastructure and re-negotiation of agreements. Based upon these over-riding revenue benefits, the existing site was determined to be the most advantageous for construction of a new tank.
Various elevated tank styles were also considered to weigh the advantages and disadvantages of all steel versus composite style tanks. The District opted to pursue the composite style tank. The existing tank will be removed after construction of the new tank and relocation of the cellular antenna. CEI completed design and permitting phase services for the new tank during the spring/summer of 2016, the project was bid in the fall of 2016 with construction occurring from 2017-2018.
CEI’s drone services provide an additional tool for water storage tank inspection. Images and video taken using the drone exceed those obtainable from ground level. The drone provides the ability to capture a full 360 degrees around the tank and views from above the tank, at vantages not seen before. The drone can be used to complete annual tank inspections without the need for climbing the tank. Additionally, images from the drone can be used for planning and scheduling of a thorough inspection that would require someone to climb the tank for a closer look at tank finishes, rust or pits, vents and other features.
CEI provided several site renderings for the new tank from various vantage points in the community. The District used these renderings at public meetings to convey what the new tank will look like as compared with the existing tank. Images below show the existing tank, the existing and new tank side-by-side and the new tank after the old tank removal from one of the vantage points. .
Existing & New Tank