Dam 6 Sewer Separation Project Reaches Substantial Completion

 In CSO Remediation, Featured News, General News, News, Public Works News

Phase II of the Dam 6 Sewer Separation Project, which began work in January, has now reached substantial completion. The project included the construction of a new stormwater-only concrete pipe that ultimately connects White Clay Creek to the overflow point of Dam 6 and hooks up to curb inlets and storm drains along the way.

The Dam 6 Sewer Separation Project was a required project for the City of Atchison to maintain compliance with the Clean Water Act of 1972 and the subsequent consent agreements that have been established between the City and the Environmental Protection Agency (EPA) and the Kansas Department of Health and Environment (KDHE).

The project was financed through KDHE’s Revolving Loan Fund program, an offering that provides below market interest rates for qualifying utility projects.

Kansas Heavy Construction served as general contractor, besting 4 other bidders to win the contract for the project. BG Consultants, the firm that designed the project, was also hired to perform construction inspection and materials testing services.

Site restoration, including final grading and seeding, will continue for the next couple of weeks, but all street closures and hard surfaces are now complete.


Project Background: As a City founded over 150 years ago, much of Atchison was originally built utilizing a single, combined sewer system (CSO). That infrastructure was great in the late 1800’s and early 1900’s, but not so great following industrialization, the Clean Water Act, and subsequent water quality standards for both water and wastewater. A combined sewer system works just fine during dry weather when all the wastewater flows to the Wastewater Treatment Plant and is cleaned prior to discharge. However, during wet weather, the capacity of the combined system is flooded, resulting in overflows of untreated sewage directly into White Clay Creek and the Missouri River.

When the Clean Water Act was originally passed by Congress, there was substantial federal money available to help fund CSO mitigation projects in cities across the country. At the time, the City of Atchison chose not to pursue any CSO mitigation projects and therefore received no federal funding to do so.

About 10 years ago, the EPA and the Kansas Department of Health & Environment (KDHE) got serious about forcing Atchison to make more substantial progress toward remediation of the combined sewer system. The City and KDHE engaged in negotiations to finalize a Consent Agreement and Final Order (CAO). The CAO became effective on December 14, 2011 and contains a series of requirements for improvements and progress that must be achieved within certain timelines. Unfortunately, there are practically no federal grant dollars available for CSO mitigation projects given today’s federal funding landscape. That effectively means that all of the expense of those required projects is now the sole responsibility of the City of Atchison.

The CAO specifically mentions the next priority for the City is to be remediation of the combined sewer overflows in both the 11th and 14th Street sewersheds. For KDHE, 11th and 14th Street are the most immediate priority because overflows occur in the open waters of White Clay Creek, whereas the other overflow points occur within the confines of the box culvert that contains White Clay Creek between the Missouri River and 7th Street.

Given the hydraulic modeling and flow monitoring data collected by Burns & McDonnell, a consulting engineering firm, staff believes that overflows from Watershed Dam 6 are the single largest contributing factor to overflows in the 14th Street sewershed, making it a natural place to begin work in that area.

Cost: Preliminary Engineering ($140,000), Design Engineering ($112,000), Phase 1 Construction ($867,000), Phase 2 Construction ($967,000)

Funding: This project is entirely funded by the City of Atchison Wastewater/CSO Capital Improvement Fund, although the project is financed through a Revolving Loan Fund with the Kansas Department of Health & Environment.

Location:  The project needs to connect White Clay Creek (on the south side of Main Street) to the Dam 6 Overflow location near the intersection of 16th Street and Atchison Street.

Contractor: Amino Brothers Construction / Kansas Heavy Construction

Status: Complete

Construction Start Date: Phase 1 – Early 2019 Phase 2 – Winter 2020

Completion Date: Phase 1 – January 2020, Phase 2 – June 2020