Hydraulic Modeling Archives - Page 2 of 2

Southern Maine Regional Water Council (SMRWC) Regional System Study

Tata & Howard was retained by the Southern Maine Regional Water Council (SMRWC) to complete a Regional System Study for the Portland Water District (PWD), Maine Water Company – Biddeford & Saco (MWCB&S), Kennebunk, Kennebunkport, Wells Water District (KKWWD), Sanford Water District (SWD), South Berwick Water District (SBWD), York Water District (YWD), and Kittery Water District (KWD).

The purpose of the study was to provide a detailed update to their 2008 Regional Water System Master Plan Study, which studied possible interconnections between the water systems within the SMRWC. A combined water distribution system regional hydraulic model was developed using the hydraulic models of each individual water system. The regional hydraulic model was used to evaluate the hydraulic feasibility and impacts of the proposed interconnections as well as the potential of transferring water from northern systems to southern systems through a completely connected and open system. The PWD and MWCB&S have large water sources and are interested in exploring the option of providing water to southern systems. The study evaluated the needed infrastructure improvements, each system’s available water supply, and demands through the potential and existing interconnections.

The study also examined the effects that the proposed system improvements and interconnections would have on water quality. Not all water systems treat water in the same way; therefore, finished water is unique to the chemicals and treatment techniques used by each system. Specifically, pertinent available data was collected and chemicals used for coagulation, sequestering, primary disinfection, secondary disinfection, corrosion control, pH adjustment, and dental health were reviewed. Raw and finished water parameters such as turbidity, alkalinity, temperature, pH, and total hardness were also collected. Of the seven participating water systems in the study, three disinfect with chloramines and four disinfect with only chlorine solution. Operating the systems together as a permanent solution to water supply concerns would require modifications to the treatment processes in some if not all of the systems. Ideally, each water system involved in water sharing would need to agree to a treatment method to give each system acceptable water quality and eliminate concerns with blending systems.

The identified improvements were based on hydraulic feasibility. Infrastructure recommendations at the interconnection locations include construction of new water mains, pressure reducing valves, and booster pumping stations.

Regional Intermunicipal Interconnection Evaluation, MA

Through a grant from the Pioneer Valley Planning Commission, Tata & Howard was retained by the City of Northampton Department of Public Works (Northampton) and the City of Easthampton Water Works (Easthampton) to complete a Regional Intermunicipal Interconnection Evaluation for the Easthampton, Hatfield, Northampton, Southampton, and Williamsburg water systems. The purpose of the study is to evaluate potential water distribution system intermunicipal connections and emergency water supply. A combined water distribution system regional hydraulic model was developed and used to evaluate the hydraulic feasibility and impacts of the proposed interconnections. The study evaluated the needed infrastructure improvements, system available supply and demands, and available supply through the potential interconnections.

Potential interconnection locations between Northampton and Easthampton were considered at four locations, between Northampton and Hatfield, between Northampton and Williamsburg, and between Easthampton and Southampton. Infrastructure recommendations at the locations include construction of new water mains, meter pits, flow meters, pressure reducing valves (PRV) and portable pumping systems. The Massachusetts Department of Environmental Protection (MassDEP) Water Management Act (WMA) permitted and registered pumping volumes for each system’s sources was evaluated for potential supply to other communities. Northampton and Easthampton have surplus supply, while Hatfield, Williamsburg, and Southampton are approaching their WMA permit or registration allowable withdrawal volumes.

The study determined the following:

Three of the four potential interconnection locations between Northampton and Easthampton could be utilized in an emergency by isolating portions of Northampton’s system. An interconnection that could serve all of Northampton would require a pumping system.
A pressure reducing valve would be required to supply Hatfield from Northampton and a pumping system would be required to supply Northampton from Hatfield.
Due to the location of the Williamsburg interconnection along Northampton’s transmission main route, and the limited amount of water available from Williamsburg, an interconnection from Williamsburg to Northampton is not feasible.

There is an existing hydrant to hydrant interconnection between Easthampton and Southampton that has been utilized to supply water to Southampton during periods of high summer demands. To supply the entire Southampton system, a pumping system would be required, and a PRV would be required to maintain adequate pressures if Southampton were to supply Easthampton.

Water Distribution System Evaluation and Tank Design, Paxton, MA

The new tank was completed in 2015 — The new tank was completed in 2016.

Town of Paxton, MA

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:

Water Storage Tank Painting, Cleaning, and Rehabilitation, Worcester, MA

CLIENT: City of Worcester, Massachusetts

PROJECT: Chester Street 0.5 million gallon water storage tank painting, cleaning, and rehabilitation

THE CHALLENGE: The Chester Street water storage tank required evaluation, repair, cleaning, and painting of both the interior and the exterior. The tank is located in a heavily populated residential neighborhood and the exterior surface had high levels of lead in the paint. Therefore, special attention to lead contamination, noise, and construction debris was required. In addition, determination of the effects of taking the tank offline were required before any work could be started.

THE SOLUTION: Analysis of the Super High Service Area using the verified hydraulic model was conducted, and the model was run under extended period simulation (EPS) to evaluate the potential pressure problems within the service area. As a result, operational modifications to the existing pump stations and service zones were recommended. Working only during daylight hours while keeping noise and debris to a bare minimum, construction crews completed miscellaneous repairs including replacing the anchor bolts, installation of overflow support brackets, modification of the access ladder, modification of the roof ladder, repair of the upper level sway rod, extension of the balcony handrail, installation of a roof handrail, and replacement of the roof finial vent. During the exterior abrasive cleaning, a containment system was utilized to prevent lead from getting into the air and soil. Once all repairs and cleaning were completed, the interior and exterior of the elevated tank were painted.

PROGRESS: Two years later, the tank is still in pristine condition, as shown in the photo above.

Water System Operations Plan, Falmouth, MA

Tata & Howard, Inc. prepared a Water System Operations Plan for the Falmouth water system. As part of the Settlement Agreement between the Town of Falmouth and the Commonwealth of Massachusetts, the Town agreed to complete a Water System Operations Plan. The purpose of the plan was to evaluate seasonal demands, current source and storage tank operations and identify system and operational changes necessary to address distribution areas with low chlorine residuals.

The Town of Falmouth’s water distribution system consists of approximately 400 miles of water mains of various materials ranging in size from six to 24 inches in diameter. The Town has five active water supply sources including both groundwater and a currently unfiltered surface supply. Each source is treated with sodium hypochlorite for disinfection with the exception of Long Pond, which includes disinfection with chlorine gas. Falmouth’s water distribution system includes four water storage tanks and a Supervisory Control and Data Acquisition (SCADA) system to run and monitor operations.

The Falmouth Water Department faced a number of challenges, including the following:

Maintaining regulatory compliance
Meeting water demands
Peak summer demands could only be met with Long Pond surface supply
Long Pond is an unfiltered surface water supply
Constant struggle to maintain treatment compliance and water quality
Seasonal impacts from turnover or algae growth
Lack of treatment to address taste, odor, and color can require severe curtailment in use of the supply
Excessive source chlorine residuals needed to maintain distribution system residual chlorine concentrations, combined with source water organics results in elevated disinfection by-products (DBP – Total Trihalomethanes and Haloacetic Acids) which are regulated compounds

The study reviewed the challenges above and recommended changes to systems operations procedures to improve water quality. We used a hydraulic model to determine water age and look at its impacts on water quality. The plan was submitted and approved by Mass DEP.

Additionally, Tata & Howard completed the design of a 3.6 mgd treatment facility which utilizes air stripping and pressure filtration technology for the removal of iron, manganese and volatile organic compounds (VOCs). The facility includes an air stripping tower, three greensand filtration units, horizontal carbon contactors, chemical storage and feed facilities, gravel pack supply well, finished water storage, and backwash holding tanks.

Capital Efficiency Plan™ including Water System Master Plan, Northampton, MA

Tata & Howard has completed a Water System Capital Efficiency Plan™ for the City of Northampton. The plan includes a comprehensive water system master plan that evaluates the hydraulics of the system as well as critical components and asset management considerations. The hydraulic analysis included completion of fire flow testing and c-factor tests. Tata & Howard developed a hydraulic model from the City’s extensive ArcGIS database and the flow test results were used in verification. Tata & Howard reviewed recommended static pressures and Insurance Service Office recommended fire flows as well as estimated needed residential and commercial fire flows throughout the system.

The Northampton water system has wide range of ground elevations, resulting in extreme high and low static pressures in some areas. To maintain recommended system pressures, a new service zone was recommended to divide the distribution system. The recommendations included a new water storage tank, pressure reducing valves and transmission main improvements. Tata & Howard also developed additional recommended water main improvements to meet fire flow needs.

The asset management portion of the project included a detailed analysis of each segment of pipe in the water system based on age, diameter, material, pressure, soil conditions, break history, and potential water hammer. Each segment of pipe was given a numeric rating based on weighted asset criteria developed in cooperation with the City. This information was used with the hydraulic evaluation and critical component assessment to determine the prioritized improvements for the system.

Tata & Howard is also assisting the City with testing of pipes throughout the system. The work includes visual evaluation of samples and pipe strength testing. An analysis of the estimated service factor of each pipe segment will be provided to the City and used to supplement the information obtained during our asset management analysis.

Distribution System Water Quality Study, Norwich, CT

Tata & Howard, Inc. was retained by the Norwich Public Utilities (NPU) in Norwich, Connecticut to perform a distribution system water quality study to evaluate the water age, water quality, and hydraulic gradient in the Taftville/Occum Service Area. The Taftville/Occum Service Area has high water age, due primarily to the large volume of the Occum Tank. In addition, high levels of total trihalomethanes (TTHM) are observed throughout the Taftville/Occum Service Area.

This study examined the TTHM concentrations and high water age in the Taftville/Occum Service Area and presents various options to help mitigate these issues.

During the course of this study the following tasks were completed:

Updated the existing WaterGEMS hydraulic model using recent system data
Collected water distribution system data on current operating conditions,
historical and current disinfection by-product samples, water age, pressures, flows, and tank levels and supply and demand data for the entire NPU system
Conducted a gradient evaluation of the affected service area and investigated potential alternatives to improve the current conditions, including making short and long term capital improvements to provide improved tank level fluctuation and improved customer pressure ranges
Performed water age modeling of the existing service area and for potential
alternatives that improve the current conditions and graphed the results
Provided information and costs for alternatives to the tank passive mixing system
Provided recommendations for improving the service area gradient(s), water age, and water quality
To evaluate the Taftville/Occum Service Area, the entire NPU distribution system needed to be examined to determine the quality of the water as it enters the service area.

The key finding from this study related to the TTHM levels in the Taftville/Occum Service Area was that the formation potential in the effluent water from both of NPU’s surface water treatment plants was high enough for the TTHMs to exceed 80 µg/L at the entry point to the service area.

Based on this study, NPU has decided to add dissolved air flotation (DAF) to its Stony Brook water treatment plant. Tata & Howard designed the DAF system and other related improvements.

On-Call Water Engineering Services, Franklin, NH

Tata & Howard has been assisting the City of Franklin, New Hampshire with general water engineering services since 2009. The Tata & Howard team has managed several phases of work, including the design and construction of the water treatment plant and distribution system improvements.

The first phase was the design and construction of 2,500 linear feet of water main on Hill Road to connect a new water treatment plant to the City’s distribution system. This project also involved use of four bioretention systems to treat and manage stormwater from the roadway, and was constructed in 2010.

The second phase of our work with the City included the design and construction of two parallel 2,500 LF sections of 12-inch diameter HDPE crossings beneath the Pemigewasset River using horizontal directional drilling to transport water from the City’s Franklin Falls Well to the water treatment plant site.

Tata & Howard managed the survey and geophysical studies and prepared a Preliminary Design Report and Environmental Review documents for several phases of work. The City’s wells are surrounded by lands controlled by the US Army Corps of Engineers, which required that we complete an extensive permitting process to secure permissions for the final design of the project.

Tata & Howard completed design, construction, permitting, and funding applications for a 1,000 gallons per minute groundwater treatment plant to remove iron and manganese from three of the City’s wells. The plant has four pressure filters containing Greensand Plus media and using sodium hypochlorite for oxidation and sodium carbonate (soda ash) for pH adjustment. This plant went online July 9, 2012.

Tata & Howard provided design services for the construction of a new prestressed concrete tank at the site of an existing tank. The existing tank was in poor condition and due to the site characteristics, it was determined that construction of the new tank on the existing foundation of the old tank would be the best option. A second tank on the site was demolished in 2013 and a new prestressed concrete tank will be constructed in its place.

Tata & Howard also conducted a full water system analysis for the City of Franklin, New Hampshire by utilizing our proprietary Capital Efficiency Plan™ methodology. Our CEP involved creating a model of all water infrastructure in the City including sources, pump stations, treatment facilities, storage facilities, transmission, and distribution lines. Using our GIS modeling software, the system was calibrated based on fire flows in an attempt to accurately replicate the existing system. We then pinpointed deficiencies within the system based on a custom rating scale given to multiple criteria such as age, break history, material type, criticality and size. Recommendations were made for improvements in order of need. The study renewed both above ground and below ground assets. Funding for this study was in part from an Asset Management Planning Grant from NHDES.

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Water and Wastewater Engineering Services: Hydraulic Modeling, Facilities Plan, WRF Improvements, Goodyear, AZ

Tata & Howard provided water and wastewater engineering services associated with the update of existing water and sewer system models using InfoWater and InfoSewer computer programs; review of the impact of proposed developments and proposed extensions to the City’s systems; verification of the hydraulic models for the City of Goodyear’s water distribution and wastewater collection systems. The water model included fire flow testing, C-value tests and calibration of the InfoWater hydraulic model. The wastewater collection system model included installation of six flow monitoring stations in three sub-basins, calibration of the model, development of a cost allocation model, and preparation of a technical report.

Tata & Howard prepared a facilities plan for the Corgett Water Reclamation Facility. The plan addressed the need for process redundancy and recommended improvements for increased flows and Class A+ effluent. Provided ongoing support services to address operational needs and to assess the impact of new developments on the system. Provided design, bidding, construction administration, resident observation, and construction services associated with improvements to the Corgett WRF including: filter system, low lift pump station, modifications to the sand filter, and instrumentation upgrades.