Highway – Northstar Hydro, Inc.

Tidal Bridge Replacement, Deer Ilse, ME

Northstar provided hydrologic, hydraulic and scour analysis for a replacement bridge at Mill Pond in Deer Isle Stonington. The bridge is affected by tidal flow and runoff to Mill Pond. Daily tides, storm tides and upland runoff all affect water levels and flow dynamics at the bridge. Channel bed at bridge is higher than lowest tide levels creating a lag in tidal inflow and an elevation difference. Deer Isle Tidal Bridge to be Replaced Bed grade at bridge causes a tidal inflow lag and an elevation difference at low tide.

By nicki_16

Tidal Culvert Analysis, George Wright Road, Woolwich, ME

Northstar assisted Calderwood Engineering in their work for the Town of Woolwich to evaluate options for improvements to the culvert that conveys tidal and upland flow under George Wright Road in Woolwich. Tide levels on the downstream end of the site are subject to the complex hydraulics of the Kennebec River/Sassanoa River/Sheepscot River tidal system with islands, inlets, side channels and other features that create complex tidal/upland flow interactions in this area. Tide hydrographs from this river complex were routed through George Stevens Road and Route 1 to assess potential impacts of changing culverts in George Stevens Road. Model HECRAS 1-D…

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Design Build of Six I-95 Bridge Crossings, Hampden, ME

Northstar Hydro teamed with Cianbro and WSP on this design-build project for MaineDOT. The project involved hydraulics of Souadabscook Stream which flowed under all six bridges under varying hydraulic and scour conditions. Project involved very tight timelines, a large project team and effective conveyance of complex information to the larger team with the DB framework.

By nicki_16

Regional Flooding Evaluation, Lye Brook, Manchester, VT

Northstar Hydro, Inc. assisted the Town of Manchester Vermont in evaluating local flooding issues associated with the area between Lye Brook and the Batten Kill. 2-Dimensional flow model of the river-wetland complex transected by several transportation corridors was developed to study flow and land use patterns. The model assisted in understanding the complex relationship between an altered stream and localized flooding. The study found that the area was an active alluvial fan 100+ years ago before the primary stream was channelized. The analysis highlighted the challenges of historic development patterns along an active stream as well as the impacts of…

By nicki_16

Highway Drainage for Proposed Interchange, Waterville, ME

Northstar Hydro worked with FST and Maine DOT to provide hydrologic and hydraulic design services for a new exit ramp from the Maine Turnpike. Northstar conducted a hydrologic analysis, drainage review, and/or sizing design of 17 cross culverts: 5 new culverts, 6 culvert extensions, and 6 additional culverts beyond the project but reviewed as part of the drainage design. The project involved an analysis of the final drainage design for a proposed new interchange on I-95 at Trafton Road in the City of Waterville and the Town of Sidney in Kennebec County, Maine. The design is a partial cloverleaf interchange with both ramp…

By nicki_16

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…

By nicki_16

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.

By nicki_16

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.

By nicki_16

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.…

By nicki_16

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…