Highway Drainage and Large Culvert Design, 5 miles of Route 3 in Bar Harbor, Maine

Highway Drainage and Large Culvert Design, 5 miles of Route 3 in Bar Harbor, Maine

Northstar worked with HNTB for the Maine DOT to provide drainage design and large culvert hydrologic and hydraulic design for over 5 miles of reconstructed Route 3 north of Bar Harbor, Maine on Mount Desert Island.  The project included a number of large culverts, some with fish passage improvements as well as several miles of closed system drainage.  Project challenges included high rates of runoff to closed drainage systems due to shallow bedrock, steep slopes and limited shoulder widths to closed systems, semi-urban developed areas, historic buildings, and aesthetic design. Northstar combined GIS tools with project data to provide efficient…
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Dam Removal, Industrial Client

Dam Removal, Industrial Client

Northstar Hydro prepared a hydrologic and hydraulic analyses for the planned breach/removal of the dam that impounded a lake originally built in the 1940’s as a water supply for an industrial mill in Pennsylvania.  The lake owner proposed to remove the dam that impounds lake and restore the stream to a free-flowing natural state.  Northstar analyzed the watershed hydrology using GIS tools and model HECHMS and studied dam removal affects using model HECRAS.
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Route 9 Bridge Kennebunk, ME

Route 9 Bridge Kennebunk, ME

Northstar Hydro, Inc. provided hydrologic, hydraulic and scour analysis to Maine DOT’s contractor for preliminary and final design for proposed replacement of the Route 9 bridge between Kennebunk and Kennebunkport.  Unsteady flow modeling with model HECRAS and field monitoring provided data on water elevations, velocities, and rate of flow through the bridge under a variety of storm and daily tide conditions. The model helped to determine whether the bridge impacted upstream water levels and provided scour related variables. The site is shown in the photo below and the tidal river is shown in the air photo.
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Landfill bank erosion and river bed restoration, Industrial Client

Landfill bank erosion and river bed restoration, Industrial Client

Northstar Hydro developed a 2-dimensional flow model of a river running adjacent to a non-operational landfill to assess the erosive properties of the river at the landfill embankment and on the river bed.   Over the decades, the river has encroached on the riverbank portion of the landfill and in some locations portions of the landfill have been eroded into the river.  Considerable amounts of waste coat much of the river bottom in the landfill area.  Using the model results, the designer has prepared a conceptual closure plan to remove a portion of the riverbed sediment containing waste and to relocate that…
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VTrans Culvert H&H Analysis, VT Statewide

VTrans Culvert H&H Analysis, VT Statewide

Northstar Hydro has conducted numerous hydrologic and hydraulic analysis of culverts for Towns throughout Vermont.  Projects are initiated when the Town requests a review of replacement alternatives for specific culverts through VTrans.  Northstar Hydro conducts a site visit, confers with local officials, assesses hydrologic flow, and recommends several culvert sizing alternatives based on hydraulic and environmental standards. Considerations include fish passage and geomorphic setting as well as hydrologic and hydraulic parameters.
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Design-Build: I-91 Twin Bridges over Williams River in Rockingham, Vermont

Design-Build: I-91 Twin Bridges over Williams River in Rockingham, Vermont

Large Bridge I-91 Northstar Hydro is part of the Design-Build Team of Reed and Reed and HDR for the replacement of the twin bridges that carry I-91 over the Williams River in Rockingham, Vermont.  NHI provided hydrologic, hydraulic, and scour analysis Northbound and Southbound (NB and SB) bridges  Work completed included hydrologic analysis, hydraulic modeling, and scour analysis based on site specific channel survey and FEMA data.  A geomorphic assessment of the river and project reach were also prepared.  Project components included consideration of FEMA elevation and floodway data, existing and proposed condition models, ice jam considerations, and scour and geomorphic assessments.…
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Androscoggin River Bridge Replacement in Durham and Lisbon

Androscoggin River Bridge Replacement in Durham and Lisbon

The existing Route 9/125 Bridge over the Androscoggin River at Durham/Lisbon Falls was recently replaced. The bridge is located approximately 1200’ downstream of the Worumbo Dam and spans the narrowest segment of the river. The bridge is founded on rock at both abutments and at the piers on rock islands. A channel that carries flow from the dam tailrace is located below the eastern opening between the abutment and the first pier. The bridge has two piers and two abutments.  Northstar provided hydrologic, hydraulic and scour evaluations associated with the design of a replacement bridge with the final alignment residing upstream of…
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Bike Path Bridges, Barrington/Warren, RI

Bike Path Bridges, Barrington/Warren, RI

Northstar Hydro, Inc. provided preliminary design hydrologic, hydraulic and scour assessments for RIDOT’s contractor for two bridges in Rhode Island that will be replaced and carry a high use bike/pedestrian path over the Barrington and Palmer Rivers in Barrington and Warren Rhode Island.  Services included contracting for detailed velocity profiling near each bridge through a tide cycle, unsteady flow modeling of both sites and computation of storm and daily tide heights and flow velocities. The bridge locations are shown on the air photo below.  Greater Narragansett Bay is south of the project locations. The second photo is the Barrington River…
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Boombridge Bridge, Greenbush Maine

Boombridge Bridge, Greenbush Maine

UpstreamBoombridge BridgeDownstream to Penobscot River This project involved hydrologic and hydraulic evaluation of Bridge #3587 for the replacement of Route 2 over Boombridge Brook in Greenbush, Maine.  The work was prepared for CLD as part of their preliminary design work for the Maine DOT on a replacement bridge. The bridge is located just upstream of the confluence of Boombridge Brook with the Penobscot River.  The bridge is subject to backwater flooding from the Penobscot River during high water events on the river.  A large low swamp or wetland area upstream of the bridge serves as floodplain storage for floodwaters from…
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Cumberland and Bridge Street Bridges over Presumpscot River in Westbrook, Maine

Cumberland and Bridge Street Bridges over Presumpscot River in Westbrook, Maine

Northstar Hydro, Inc. worked with Stantec and the Maine Dept. of Transportation on the replacement of several bridges on the Presumpscot River in downtown Westbrook, Maine.  Northstar provided hydrologic, hydraulic and scour engineering services in association with the replacement of the twin Cumberland Street Bridges and the Bridge Street Bridge.  The Cumberland Street twin bridges are located directly upstream of the Sappi Mill dams, fishway and production buildings.  Both the dams and the buildings affect flood waters downstream of the twin bridges.  Hydraulic modeling required detailed understanding of flow through the complex mill dam system and buildings.
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