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WATER
RESOURCES PROJECTS
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Three
Forks Flood Study
Three Forks, Montana
The Three Forks Flood Study
of the Madison and Jefferson Rivers in the vicinity of
Three Forks, Montana was used to create updated FEMA Flood
Insurance Rate Maps. The project consisted of project management
for surveying, creation of base maps and floodplain mapping.
Allied Engineering utilized state-of-the-art software including
HEC-GeoRas and ArcView with 3D Analyst to perform the flood
mapping. The study reach included upstream and downstream
of the junction between the two rivers. The floodplain modeling was performed
with the computer program HEC-RAS and involved complicated
flow spits, levees, ice jamming analysis, and numerous
bridges. This study was completed in 2005.
Key project
elements were automated
geometry extraction and floodplain mapping, compliance
with FEMA Guidelines and specifications for flood hazard
mapping partners, floodplain mapping for an area covering
roughly 7.5 square miles and over 6 miles of river studies,
and over 40 bathymetric cross-sections utilizing
GPS, a boat, and conventional techniques.
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Yellowstone County Floodplain
Studies
Yellowstone County, Montana
Allied Engineering provided floodplain maps to Yellowstone
County for a re-study of Cove Creek and a new study for
Five Mile Creek.
This project included surveying cross-sections, hydrologic
and hydraulic analyses, and production of floodplain maps.
The total stream lengths were over 10 miles. Allied teamed
with Van Mullem Engineering who provided the hydrologic
and hydraulic analyses. Allied provided surveying, base
map creation, and floodplain mapping. These studies were
completed in 2004.
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South Fork Stream Reclamation
& Bank Protection
Big Sky, Montana
Unauthorized dumping of
waste fill from the construction of an up slope road caused
damage to the South Fork stream near Big Sky, Montana.
The unauthorized fill was incorporated into the design
and used to construct a vegetated floodplain bench and
rock barbs to provide long-term protection from bank recession.
Allied provided engineering
design and permitting services, along with surveying and
construction oversight and inspection. This project completed
in 2004, required
HEC-RAS modeling and extensive permitting with State and
Federal Agencies.
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Kerns Lake Dam Rehabilitation
Powell County, Montana
Allied Engineering provided engineering analysis, design, permitting, and construction documents for the Kerns Lake Dam Rehabilitation. Major elements of the rehabilitation included flattening embankment slopes, adding internal drainage to enhance slope stability, and replacing the low level outlet and an outlet control tower. Internal drainage included a diaphragm filter and a two-stage toe drain that utilized natural on-site gravel along with smaller amounts of imported coarse aggregate. Allied Engineering is also providing construction staking and inspection. This project involves coordination with the Department of Natural Resources and Conservation State Water Projects Bureau and the client - Correctional Enterprises Ranch.
Key Project Elements:
• Regulatory Permit Coordination
• Geotechnical Investigation
• Topographic Survey
• Low Level Outlet Replacement
• Upstream Slope Remediation
• Downstream Seepage Control Berm and Drainage System
• Preparation of Design Report, Plans, and Specifications
• Construction Oversight.
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Clearwater River Fish Barrier Removal Project
Missoula County, Montana
Allied Engineering in conjunction with Mainstream Restoration designed approximately 200-feet of steepened river channel to replace an aging log crib dam on the Clearwater River just upstream of Seeley Lake. The timber crib dam prevented upstream migration of fish because of the roughly 10-foot drop from the dam spillway structure. The objective of the replacement river channel will be to provide upstream passage to salmonids while restricting upstream passage to Northern Pike. The replacement channel will also need to meet the aesthetic objectives of the landowner. An embankment retrofit and a new emergency spillway were also designed.
The most challenging aspect of the project involved designing the steepened river channel to be stable on slope of roughly 5% with the 100-year flow (approximately 2,000 cfs) and fish passage during the annual low flow (approximately 15 cfs). This wide variation in design flows required careful design of the rock gradation and placement in the channel.
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Tongue River Diversion Dam Removal
Custer County, Montana
The SH Dam was located approximately 45 miles southwest of Miles City, Montana. The Montana Department of Fish Wildlife & Parks completed the project to restore migration of native warm-water fish species that live in the Yellowstone River and its tributaries. The project consisted of removal and disposal of 300 lineal feet of a concrete irrigation structure on the Tongue River. Allied Engineering's scope of work included an Environmental Assessment, Design, Construction Documents, and assistance with Bidding, and Construction Management.
Key Project Elements:
• Analysis of impounded sediment to estimate the significance of downstream release of sediment after dam removal. Utilized the sediment transport functions in HEC-RAS to characterize sediment transport based upon available sediment gradation data and the mean of the mean daily flow data from the USGS for a nearby stream gage.
• Environmental Assessment - Finding of No Significant Impact
• Construction Documents - Produced plans and specifications from very limited field survey data.
• Post-Construction Inspection
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Pine Creek Remediation Project
Calumet County, Wisconsin
The Hayton Area Remediation Project (HARP) is a PCB-contaminated site on Hayton Mill Pond and its tributaries near Chilton, Wisconsin. TRC Environmental Corporation was tasked with undertaking remediation of the contaminated site. The remediation involves the modification and reconstruction of portions of Pine Creek and the associated floodplain. Mainstream Restoration and Allied Engineering were contracted to design the post-remediation stream and floodplain restoration, prepare construction documents, and assist with permit acquisition.
Allied Engineering served as the project engineer provided surveying, data management, AutoCAD drafting, GIS analysis, hydrologic and hydraulic analysis and modeling, design, and permitting plans for a restoration of a 4.1 mile reach of Pine Creek in Calumet County, Wisconsin.
Key Project Features:
• Surveyed 30 stream channel cross-sections.
• Built a georeferenced HEC-RAS model of the 4.1 mile project corridor. The geometric model was extracted by combining limited and rough floodplain survey data by TRC with detailed cross sectional data obtained by Allied Engineering and Aerometric, Inc.
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