Red Mountain South LID Project

Location

Kennewick, WA

Client

Kennewick Irrigation District

Service

Irrigation, Environmental, Structural, Electrical, SCADA, Geotechnical, Construction

Completed

2014

The Kennewick Irrigation District’s (KID) Red Mountain South Local Improvement District (LID) project is a new 6,300 gpm pump station and freshwater intake off the Yakima River, and also includes 15 miles of pipelines, a 1,750 gpm booster pump station, and two reservoirs. Construction of the $5.3 million Kiona Intake and Booster Pump Station was the first phase in an approximate $12.4 million construction project to bring irrigation water to the prestigious Red Mountain American Viticultural Area region. The primary pump station is the main supply source for the newly developed Red Mountain South LID irrigation system, which serves 1,785 acres of irrigable lands where some of the region’s finest wine grapes are grown.

Preliminary designs for the project looked at various sources of water, including the surface water intake, wells in hydraulic continuity with the river, and extending pipelines from the existing KID main canal supplies. RH2 prepared an extensive predesign report that concluded that the best alternative was to pump out of the Yakima River at Kiona. The project would be economical for farmers while provide significant instream flow benefits to the Yakima River between Prosser and Kiona of over 9,000 acre-feet of additional water per year.

The environmental permitting for the project presented a number of challenges due to the site’s proximity to the Yakima River, which provides a habitat for salmon listed on the Endangered Species Act. As a result, access to the river during the construction of the intake structure was limited and confined to a narrow 2-month window from mid-July to September. In addition, the topography of the site made access extremely difficult, which was further complicated by the fact that the entire site is predominantly basalt bedrock. The project required extensive rock blasting, excavation, structural earth retaining walls, and grading to prepare the site for the new facility.

RH2 prepared cost estimates at 30-percent, 60-percent, and final design with construction costs ranging from $14.9 million to $17.5 million dollars. As final design was completed, RH2 was able to find opportunities to reduce costs by careful construction phasing and organizing the project into smaller contracts where specialty contractors could bond and build specific project components. The final eight construction contracts at the time of bidding totaled $12,835,000. RH2 also provide construction administration and on-site observation services to help manage the many facets of the project concurrently. This allowed additional value engineering to occur during the construction phases, further reducing the overall project cost. Final completed construction costs at the end of the project totaled $12,417,000 which was 3 percent under the contract price and more than 15 percent lower than the estimated cost of $14.9 million at the 60-percent design stage.

For more information on this project, click the link above for Irrigation Leader Magazine's article starting on page 12.