East H Street Reconstruction, McCook NE
This project involved the repaving of an existing asphalt street with new 8″ concrete pavement. The existing asphalt was milled from the street, the subgrade was regraded and compacted and then 3″ of the millings were laid back as a base for the new pavement. The existing curb and gutter was in good condition as was not replaced. ADA accessible ramps were installed on all corners.
Included in this project was a major intersection with an arterial street. In order to minimize disruptions to the public this intersection was replaced through a stringent phasing plan which allowed i to be opened to traffic well before completion of the project.
W Design Associates provided design and construction administration services on these projects. Overall these projects were completed on time and within budget. Mr. Greg Wolford was the project manager for these projects.
McCook Water Treatment System, City of McCook NE
The City of MCook its water supply from the Republican River Alluvium. This source water exceeds the maximum contaminate levels by 50 percent for nitrate, arsenic, and uranium. As a result, the Nebraska Department of Health and Human Services (HHS) issued a compliance letter requiring the City to meet the maximum contaminant levels (MCL) for nitrate, arsenic, and uranium by completing designing and construction of a water treatment facility The City chose a team (essentially, the same individuals as this team to design the required treatment plant. HHS imposed extremely stringent deadlines for the project, and due to this shot time frame, an accelerated design and construction schedule was implemented. Through treatment process evaluations, Ion Exchange with with Softening Pretreatment was selected for final design. The decision was based upon economic impacts, operational ability, and waste generation and disposal. The water treatment system was designed for a peak-day capacity of 6.8 MGD, and an average-day of 2.5 MGD. A pilot test was performed to determine and confirm operational parameters. Based upon the results of the pilot study, the treatment plant equipment was bid and construction of the water treatment plant was completed in 10 months. The plant went on-line in February 2006, nearly two months before the deadline, thus exceeding the compliance requirement set forth by the regulatory agencies. Included in the design was an 8.64 MGD Booster Pump Station used to pump the treated water into the McCook distribution system.
The disposal of water treatment plant wastes poses challenges, and this innovative project was one of the first of its kind in the country to remove nitrates, arsenic, and uranium in one process. In McCook, deep well injection was selected for waste disposal, which was the first time this technology has been used in the State of Nebraska for this purpose. The deep well has been in operation since 2007 and has performed without any issues.
Other innovative aspects of the project included the fast track scheduling imposed by the regulatory agencies and the use of chloramines to disinfect the water to reduce disinfection byproducts.
Green Street in Thelan Subdivision, Wood River NE
This paving district was created to pave six block of gravel roads and improve drainage in a new development area on the north side of Wood River. The project included over 8,000 square yards of concrete street, curb and gutter, 500 feet of concrete drain pipe, 8 curb inlets as well as some water and sewer utility work associated with the paving project.
The most challenging part of the project was to design and control construction within the extremely flat slopes to work within the constraints of the existing infrastructure. The streets were paved with slopes as shallow as 0.292% and most at 0.30% slope. A summer 2007 inspection after a rain shower showed the success as there were only a few puddles of 1/4″ or less on the whole project. A high degree of project control was required not only due to the shallow slopes but portions of the project were completed in existing residential areas.
Project administration also included assistance tor the City Attorney in preparing district boundary maps as well as final assessment certifications.
Valentine Community Schools Running Track, Valentine NE
W Design Associates has designed and provided construction inspection services on many tracks in Central and Southwest Nebraska. This work has included asphalt and concrete tracks with no surfacing, latex rubber surfacing and polyethylene rubber surfacing.
The services we provide have included site survey, new facility layout, facility modifications, preparation of bid documents (plans and specifications), subgrade testing, pavement inspection and testing, surfacing inspection and construction administration.
