Situation

Colorado Springs, CO is the county seat and the largest city in El Paso County in Southern Colorado.  El Paso County's population is anticipated to grow at a rate of 1.9 percent a year through 2030, or 350,000 additional people.  To satisfy their growing need for municipal water, Colorado Springs and their partners have chosen to invest in their future and have developed plans to construct the Southern Delivery System to utilize their water rights from the Arkansas River.  This system consists of the design and construction of a 66 inch welded steel pipeline and water system that will transport raw water 47 miles from the Pueblo Reservoir to the future Colorado Springs water treatment plant.

Included in the system are a dam connection, raw water pump stations, 47 miles of 66 inch raw water pipeline, a treatment plant initially capable of treating 50 million gallons per day expandable to 100 million gallons per day, finished water pump stations, and approximately 9 miles of 42 inch to 54 inch finished water pipeline, at a Phase I cost of approximately $1 billion financed with 40 year bonds.  Due to the magnitude of the overall project it was designed and constructed in phases and segments.

Solution

Layne contracted with Colorado Springs Utilities to construct Segments 3 and N1C/N2A, which totaled approximately 13.7 miles, of the 66 inch raw water pipeline.  Segment 3 is located just north of Pueblo West. The southerly 5.3 miles of the alignment is through an environmentally sensitive working cattle ranch and the northerly 2.3 miles are through a ranchette community.  The majority of the project was installed in sandy material, but there was also 7,350 cy of rock that had to be excavated for installation of the pipeline.The depth of excavation ranged from approximately 14 feet to 45 feet.

SDS Segment N1C/2A is 6.1 miles and consisted of 32,260 LF of 66” welded steel pipe, 3 air/vacs w/ structures, 4 blowoffs w/ structures, 240 LF of 84” steel casing tunneled beneath Bradley Road, the primary access to Schriever Air Force Base, the crossing of numerous above and below ground high voltage electric lines, the crossing of high pressure petroleum lines, traffic control, reclamation, riprap structures, earthwork, cathodic protection, and hydrostatic testing to 394 ± psi.  The welded steel pipe is bedded with a combination of CLSM and aggregate bedding.  The project also required the use of cost loaded CPM scheduling.

In the deeper areas, the 150 foot wide construction easement was very tight, but due to the environmentally sensitive nature of the surrounding lands it was critical to stay within the easement.  The lower 70% of the pipeline was backfilled with CLSM, and the upper 30% percent was backfilled with select native materials.  A batch plant was set up on the project site, and CLSM was produced using the native soils as aggregate, but due to the quantity of CLSM offsite sources also were required. 

Layne Heavy Civil, Inc. received a "2014 Top Projects Award" by Water and Wastes Digest for our successful involvement in the construction of the Southern Delivery System.

Services employed

  • Pipeline Construction
  • Water Main Construction