Hydraulic Structures

{id=61570585121, createdAt=1639074811182, updatedAt=1646949409305, path='st-vrain-diversion-replacement', name='St. Vrain Diversion Replacement', 1='{type=string, value=St. Vrain Diversion Structure Replacement}', 33='{type=number, value=0}', 34='{type=list, value=[{id=10, name='Civil Infrastructure', order=4, label='Civil Infrastructure'}]}', 4='{type=string, value=When historic floods damaged the St. Vrain Diversion Structure, a design-build team was contracted to replace the hydraulic structures as quickly as possible. Read how Alden meet the aggressive schedule.}', 5='{type=list, value=[{id=19, name='Government', order=4, label='Government'}]}', 6='{type=list, value=[{id=1, name='Hydraulic Structures', order=0, label='Hydraulic Structures'}, {id=9, name='Water Conveyance', order=8, label='Water Conveyance'}, {id=15, name='Structural Design', order=14, label='Structural Design'}, {id=16, name='Structural Engineering', order=15, label='Structural Engineering'}]}', 7='{type=list, value=[{id=9, name='Engineering', order=8, label='Engineering'}, {id=10, name='Construction Services', order=9, label='Construction Services'}]}', 39='{type=string, value=st-vrain-diversion-replacement}', 8='{type=string, value=

The Highland Ditch Company services more than 40,000 acres of farmland. Its primary diversion infrastructure is located near Lyons, Colorado, along the St. Vrain River in Boulder County.

In September 2013, a five-day rainfall exceeded the annual average in Boulder County. The resulting flood destroyed Highland's diversion dam and headgate structure, which were built in 1870.

A design-build team was contracted to replace the hydraulic structures as quickly as possible so the system would be operational before spring runoff. The accelerated schedule was implemented so that water would be available for the 2014 irrigation season.

Alden's role included:

• Hydrologic analysis
• Hydraulic design
• Structural engineering
• Field inspections and engineering services during construction

The project design accommodated short lead times and readily available materials. Our team also developed rebar and steel shop drawings, which saved several weeks in the schedule.

The project features include:

• 350 cfs diversion structure with 5 headgates
• Sluice structure with 2 sluice gates
• 70’ long diversion dam, including a grout curtain below
• 60’ long trash rack
• More than 100’ of concrete retaining walls and wing walls
• Scour protection
• 800’ long trapezoidal channel

This project started only weeks after the historic flood event in September 2013.  Alden worked closely with the contractor to meet the aggressive schedule; construction was completed on February 5, 2014.

}', 13='{type=image, value=Image{width=976,height=781,url='https://20952198.fs1.hubspotusercontent-na1.net/hubfs/20952198/PROJECTS/ALDEN/St-Vrain/After-2013-Flooding.jpg',altText=''}}', 14='{type=string, value=After 2013 flooding}', 15='{type=image, value=Image{width=1430,height=1072,url='https://20952198.fs1.hubspotusercontent-na1.net/hubfs/20952198/PROJECTS/ALDEN/St-Vrain/After-2013-Flooding-debris.jpg',altText=''}}', 16='{type=string, value=After 2013 flooding}', 17='{type=image, value=Image{width=1430,height=1073,url='https://20952198.fs1.hubspotusercontent-na1.net/hubfs/20952198/PROJECTS/ALDEN/St-Vrain/Construction-of-replacement-structure-2.jpg',altText=''}}', 18='{type=string, value=Construction of replacement structure}', 19='{type=image, value=Image{width=948,height=799,url='https://20952198.fs1.hubspotusercontent-na1.net/hubfs/20952198/PROJECTS/ALDEN/St-Vrain/Construction-of-Replacement-Structure.jpg',altText=''}}', 20='{type=string, value=Construction of replacement structure}', 21='{type=image, value=Image{width=1182,height=500,url='https://20952198.fs1.hubspotusercontent-na1.net/hubfs/20952198/PROJECTS/ALDEN/St-Vrain/hydraulic-structures.jpg',altText=''}}', 22='{type=string, value=After new construction}', 25='{type=number, value=0}', 27='{type=number, value=1}', 28='{type=number, value=1626695165000}', 29='{type=number, value=120}', 30='{type=string, value=

What does an accelerated timeline look like?

• September 12 - 15, 2013: Peak of flooding; St. Vrain diversion structures fail
• September 17, 2013: Engineering team, contractor, and owner meet at the site; design begins
• October 5, 2013: Contractor begins reconstruction of the canal
• October 30, 2013: First concrete placement for the new diversion structure
• December 15, 2013: St. Vrain Creek is first diverted to Highland Ditch
• February 5, 2014: Construction completed

}'}