Bridges – 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…

By nicki_16

Skewed Bridge, Madawaska- Edmundston International Bridge, Madawaska, ME

The International Bridge over the St. John River between Madawaska, Maine and Edmundston, New Brunswick is being replaced. Northstar Hydro prepared the hydrology, hydraulics and scour analysis for this bridge replacement, facing the following issues: · Stakeholders represent international team, including MaineDOT, NBDOT, border control for United States and Canada, local residents, paper mill on both sides of the river, and other businesses and interests. · 2-Dimensional flow model employed. · River hydraulics see widely varying flood levels. · Simulation included existing bridge at 90 degree angle to flow and new skewed bridge. · Specific distribution of water levels over…

By nicki_16

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

Town of Brownville Junction, Maine

Culvert Replacement with Fish Passage Northstar worked with Dirigo Engineering to provide hydrologic and hydraulic engineering at the stream crossing of Front Street in Brownville Junction, Maine. The Town of Brownville proposes to replace the Front Street culvert, removing the existing undersized, perched structure with a larger hydraulically sufficient culvert that would also restore aquatic passage at the site. The existing culvert is described as two old tank cars butted end to end with the middle seam pulling apart and failing. The culvert has overtopped downstream end of the culvert is perched above an existing scour hole and is experiencing erosion…

By nicki_16

Benjamin River Bridge between the Towns of Brooklin and Sedgwick, Maine.

Tidal Bridge Replacement Project Northstar Hydro worked with Kleinfelder and Maine DOT to provide hydrologic, hydraulic and scour engineering services related to replacement of the Benjamin River Bridge. Preliminary design identified key project issues including storm tide elevations, tidal cycling through the bridge, combination of tidal and upland flows and ongoing scour. The scour critical bridge was modeled using a GIS based dynamic HECRAS hydraulic model to simulate normal and storm tide conditions as well as upland flooding. Field data of tide elevation and flow velocity was also collected to provide calibration data for the hydraulic model.

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

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…

By nicki_16

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…