End Street Drainage Ravine Restoration & Stormwater Management Project
Chicopee, Massachusetts

This project was necessitated by the failure of a 24 inch storm sewer which drains the Edgewood Avenue/ Clairmont Avenue/End Street area. Over the course of time, the head of the ravine eroded until it undermined the pipe at which time the rate of erosion markedly increased. A large scour hole developed with unstable vertical sides approximately 30-35 feet high.

Green developed a restoration plan and balanced cut and fill materials on-site by cutting unstable slopes back to 2:1 ratios for all slopes and filling the scour hole with more than 3,300 cubic yards of material. Green performed extensive hydrologic/hydraulic analyses to evaluate existing and post-construction conditions.

The End Street project required reconfiguring and extending more than 550 feet of gasketed drainage pipe with the innovative use of vortex valves around the stabilized scour hole to the bottom of the ravine where energy dissipation could be properly addressed. An energy dissipator was designed at the pipe outlet to prevent scour. The high flow bypass pipe was incorporated into the project to prevent catastrophic slope failure during extreme storm events. The design solution prevents further erosion and provides an adequate outlet for discharging drainage from the area. Green prepared a detailed landscaping plan to restore wetland functions and values in harmony with the surrounding natural landscape.

North Reading Flood Study & Floodwall

Green has served as the floodplain management consultant for the Town of North Reading, MA since the 1990's. Green updated the FEMA Flood Insurance Study for the entire Martins Brook Watershed on behalf of the Town through FEMA's Cooperating Technical Partners (CTP) program. FEMA provided a grant for the Town to perform the necessary hydrologic and hydraulic analyses that allowed new floodplain maps (FIRMS) and profiles to be developed. Under a separate project, Green performed design and construction services for a flood improvement project for the Town funded by a FEMA Hazard Mitigation Grant to upgrade several deficient culverts and build a flood wall and stormwater pumping station at the Town’s Public Safety Building , which is located in the Ipswich River floodplain. The new floodwall at the Public Safety Building (Police and Fire Stations) has already prevented major flood damage during three separate flood events since it was built.

City of Haverhill Watershed Management Plan

Green developed a Watershed Management Plan entitled Guidelines for Source Protection Through the Year 2005 for the City of Haverhill . The plan focused on protecting the quality of raw water in surface water supplies from pollution, especially from stormwater runoff, through the use of Best Management Practices (BMP’s). Haverhill has four active and two reserve surface water supplies with a contributing watershed area of more than 10,000 acres. The contributing watersheds extend into six abutting communities (four of which are in New Hampshire ). At the time of the study, the City's population was more than 50,000 and the City consumed about 6.3 million gallons of water per day. The key goal of the plan was to reduce treatment costs by preventing degradation of raw water supplies and to promote passive recreational activities on public lands in the watershed which are consistent with good watershed management.

MWRA Heath Hill Section 52 Phase 2 Rehabilitation

Green has completed, as the prime consultant, a $2.4 million design contract, the rehabilitation of 11,500 linear feet of the Heath Hill Section 52 pipeline, a 54” steel water main located in Brookline and Boston, Massachusetts.  Green conducted a external and internal pipe inspection program. From this program, Green determined the most cost effective method of rehabilitation, which ranged from cleaning and cement mortar lining to full pipe replacement. Site considerations required that other rehabilitation methods, such as sliplining and trenchless technologies, be implemented where the existing pipe was found not to be structurally sound.

Green developed life cycle cost analyses in conformance with the Authority’s procedures for all alternative rehabilitation methods to ensure the recommended alternative in the Preliminary Design Report was the most cost effective and constructible rehabilitation approach.  Following Preliminary Design, Green completed Final Design Plans for the approved rehabilitation method. Green provided Construction Administration Services, including resident inspection.  The project was successfully constructed on schedule and within budget limitations in 2008.  The project received the 2009 ACEC Gold Design Excellence Award for its recognition of innovative trenchless technology techniques.

MassDOT (MBTA) Merrimack River Bridge Scour Analysis

Green performed the Hydraulic and Scour Study as part of the rehabilitation of the MBTA Railroad Bridge No. H-12-061(AIF) over the Merrimack River in Haverhill, Massachusetts (aka. the Merrimack River Bridge).  The study included an evaluation of the hydraulic performance of the bridge and was conducted in a manner consistent with the American Railway Engineering and Maintenance-of-Way Association (AREMA) and the Federal Highway Administration (FHWA). The Merrimack River Bridge (built 1919), has five truss spans, including four deck truss spans and one though truss span, and carries two MBTA tracks over the Merrimack River.  The bridge superstructure is supported by four stone masonry piers and two stone masonry abutments at the river crossing. The total span length of the bridge is 712 ft across the river.  Green performed the hydraulic and scour/stability analysis using the U.S. Army Corps of Engineers (USACE) HEC-RAS Program.  Green performed the scour/stability analysis and reviewed underwater inspection reports prepared for the Merrimack River Bridge to confirm the validity of the scour analysis. Based on the scour results, Green developed two scour countermeasure alternatives and prepared a summary of conclusions and recommendations.

FEMA Flood Studies - Region I

Green performed the restudy of the Flood Inusrance Study for Sudbury, MA under Contract #EMW-94-C-4406 with FEMA.  The Scope of Work for the restudy included performing hydrologic analyses for the Sudbury River and a number of tributaries to the Sudbury River.  The Scope of Work also included extending the limit of detailed study further upstream for several of the tributaries to the Sudbury River and developing new hydraulic models for several other streams.

Green performed community consultation, data research, field reconnaissance, field survey and hydrologic analyses. Green has also developed new HEC-2 computer models for several other streams.  Green has performed a Log Pearson Type III analysis of two USGS gage stations as part of the hydrologic analysis for the Sudbury River.  Green compared flood flows it developed with historical flooding information and coordinated its work with the Army Corps of Engineers, as the Corps was performing its own hydrologic analysis of the Sudbury River in Framingham for a separate project. The hydrologic analyses for the tributary streams involved delineating drainage boundaries and performing an analysis using regional regression equations. Green performed HEC-2 analyses of the Sudbury River, and a number of tributaries to develop flood profiles for the 10-year, 50-year, 100-year and 500-year flood events. 

BWSC Bulfinch Triangle CSO Separation

Green designed separate sanitary sewer and storm drainage systems for the Bulfinch Triangle District in Boston.  The Bulfinch Triangle District is one of the City’s most important business districts, as well as a principal commuter transportation hub, and a very popular sports and entertainment venue. It is also one of the City’s premiere areas of architecturally and historically significant buildings and streetscapes.

Currently, the 14-acre project area is served by combined sewers, which contribute Combined Sewer Overflows into the Charles River during heavy storm events. The goal of the project is to redirect the sources of stormwater from the Bulfinch Triangle area that are currently tied into the combined sewer system to new storm drains and to create a new separate stormwater outfall.  The biggest challenge for this project was finding a route for a new 42” drain that had to run from the corner of Merrimack Street and new Chardon Street to Causeway Street. The Team investigated converting the combined sewer in Canal Street to a drain, but eventually determined that running down Portland Street was the best alternative.  The design for the project also involved modification to an existing Regulator Structure on BWSC West Side Interceptor by removing the existing tide gates and installing a new overflow pipe with gate valve to control, and ultimately eliminate, CSO overflow to BWSC outfall BOS049.