Preliminary CSO Controls will include separation, underground storage facilities and collection system technologies.
|
 |
Omaha like many other older cities is wrestling with problems resulting from an
old sewer system that was designed for very different conditions and standards
than it faces today. As a result, the sewer system has difficulty keeping up with
the demands that are placed on it during heavy rain storms and overflows are sent
to the Missouri River and Papillion Creek.
The City of Omaha’s Department of Public Works has begun the planning phase of
a long-term program to control combined sewer overflows (CSO). The City has partitioned
the CSO study of its 51-square-mile service area into ten different basins and assigned
an engineering team to each basin. Wade Trim, teamed with Lamp, Rynearson & Associates,
DLZ, EDC, and Thiele Geotechnical, is working on a solution for one of the more complex
basins - the Leavenworth CSO Basin.
The Leavenworth CSO Basin is partly within the downtown area of Omaha. The project team
will evaluate a variety of alternatives to determine the best way to control two major
overflows in this area including separation, in-system storage, treatment options and a
deep storage tunnel. The Leavenworth CSO Basin study area includes US Army Corps of Engineers
flood control projects that must be incorporated into the project as well as ConAgra, a major
user of the sewer system.
Alternatives evaluation is a comprehensive process that will be conducted over several
years. Initial efforts to review data and develop preliminary alternatives began in August of
2006. Field work will be conducted to gather additional data that will be used to screen
preliminary alternatives during the winter of 2007. Modeling of alternatives will be performed
using the InfoWorks software package that was selected by the City. Further evaluation of
alternatives will be conducted in 2008 and the final approach is due to the Nebraska Department
of Environmental Quality in October of 2009.
An active public involvement process will be used to educate the public about the program
and how they will be affected. City-wide and basin-specific meetings will be held to gather
input on criteria and weightings that will be used in the final alternative analysis. Both
cost and non-economic criteria will be carefully considered in finding not necessarily the
least-cost alternative but the best fit for the City of Omaha and the public.
Wade Trim has been helping Michigan, Ohio and Pennsylvania communities tackle these types
of sewage overflows since the early 1990s, pioneering engineering methods to control and treat
the mixture of storm water and sewage generated during large rain storms. Lessons learned
from these communities will be valuable to finding the best CSO solution for a portion of
Omaha’s downtown area. Our experience working with other teams to address CSO issues
will help to develop approaches that may benefit multiple basins. The final recommendation
will be folded into a plan for Omaha’s entire service area that will be implemented over
the next 20 years.
^Top
|
