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CSO Papillion Creek System
A combined sewer overflow (CSO) is a discharge of raw sewage mixed with stormwater into local waterways during a wet weather event, such as a rainstorm. Overflows occur when there is too much of this mixture for the sewer system or treatment plants to handle. To relieve pressure in the system and minimize backups into homes and businesses, excess sewage flows into local waterways.
A combined sewer is a one-pipe sewer that is designed to convey both stormwater and sanitary sewage. During dry weather, sanitary sewage alone is conveyed to a treatment facility. During wet weather, a mixture of stormwater and sanitary sewage is conveyed. With as little as 0.1” of rainfall, combined sewers can reach full capacity and begin to overflow to the Papillion Creek or Missouri River.
CSOs contain raw sewage, which can be the source of disease-causing organisms. In addition, the pollutants in CSOs can adversely affect fish and other aquatic life and can create aesthetic problems – such as odors and sewage waste and debris.
Omaha’s combined sewer collection system dates back to the 1800s and was designed to move wastewater and stormwater out of the increasingly urbanized areas and allow the Missouri River to disperse and carry pollution away. By the 1960s, it became apparent that dilution was not the total solution to pollution, and a system of diversion structures, lift stations, and interceptor sewers was constructed to direct dry weather flow (sanitary sewage) to treatment plants before discharge of treated wastewater to the Missouri River.
Since the 1960s, Omaha’s newly constructed sewer systems include separate pipes for wastewater and stormwater, and many projects have been initiated to separate parts of the existing combined sewers to prevent backups of sewage into basements. However, we still have most of the older combined sewer system in use.
A Combined Sewer Overflow (CSO) contains raw sewage and pollutants that include human bacteria and viruses, chemicals, oils, animal wastes and other contaminants that all have the potential to cause health concerns and illness. A CSO allows millions of gallons of untreated sewage and stormwater to enter the waterways in a typical year. Concerns associated with these discharges include:
- The possibility of human contact with raw sewage that can carry disease-causing organisms
- Impacts of aquatic life, such as fish
- Impacts on stream and park recreation. Most area streams do not meet the state’s water quality standards for recreational activities, such as swimming or wading
- Offensive odors and unsanitary debris along banks of rivers and streams
The extent of the health concerns from a CSO discharge depend on the amount of water dilution from the size of the receiving stream, the amount of precipitation that causes the overflow, and if the overflow occurs during peak sewage periods such as the morning or evening.
A separate sanitary sewer system is a collection of pipes located under streets and easements that are designed solely to transport sewage away from the sanitary fixtures inside homes, businesses, and industry and convey it to the wastewater treatment plant. This system protects public health by treating human and industrial wastes to reduce pollutant concentrations so they can be safely discharged to the Missouri River or Papillion Creek. Cities that have these systems must also have a separate sewer system to handle stormwater.
There are currently about 772 U.S. communities subject to CSO regulations. Most of these communities are located in the Northwest, Great Lakes, and Northeast portions of the country. This map shows those areas that have combined sewer systems and are on the EPA’s list of regulated CSO communities.
Even when CSO Solutions are implemented, stormwater from our City will flow to streams and rivers during wet weather events. This stormwater picks up pollutants as it flows across the land, whether it comes from streets, open areas, or rooftops. You can help to reduce this pollution by:
- Disposing of household chemicals and used oil properly, and not pouring them down storm sewers
- Picking up after your pets
- Fixing fluid leaks from vehicles
- Applying lawn chemicals in a way that minimizes runoff in to storm sewers
- Implementing Green Solutions
To learn about more ways to reduce pollution, you can invite the City to make a presentation to your civic associate or neighborhood group. Just indicate your interest in an educational opportunity on the Contact form.
In the combined sewer service areas, one pipe exists to convey both sewage and stormwater. When the runoff from rain adds to the sewage component of the flow in the sewer, the system relieves itself to a creek or river at a CSO outfall. If there were no designed overflow points, the excess sewage mixture would overflow at other low-lying locations, like basement floor drains.
The rates for sewer user fees are based on the costs of service by customer classification. All customers of a given class (residential, commercial, industrial) pay at the same rate, based on their contribution. All customers (inside and outside Omaha*) will help fund the CSO improvements necessary to meet the federal mandates that will improve water quality for the greater Omaha region.
*Included in the service area are the cities of Omaha, Bellevue, Papillion, La Vista, Ralston, Gretna, Bennington, Boys Town and Carter Lake.
Wastewater service is a utility, like water and gas service, with charges based on contribution. However, beginning in 2011 customers that qualify for energy assistance will also receive a utility bill credit to help with rising sewer fees. The City also plans to work with local utilities and state agencies to review the existing utility assistance programs and look for ways to improve or enhance assistance to low and fixed income customers.
Nebraska water quality standards and definitions can be found in the Nebraska Department of Environmental Quality’s Title 117. The main type of impairment in the metropolitan area is bacteria, and controlling CSOs will allow attainment of the standards in many Omaha streams.
Wastewater service is generally considered a utility, like water and gas service. Federal law requires that costs for wastewater service meet certain “equity” requirements, in terms of cost recovery.
In developing the Long Term Control Plan, Omaha considered how the CSO solutions were integrated into a comprehensive watershed management plan for stormwater. In most cases Green Solutions will serve as an enhancement to the structural controls that form the backbone of the CSO control plan.
Sewer separation work will be funded through fees collected from all users of Omaha’s regional treatment system. The impact of recently approved rates will mean the typical residential, who currently pays about $15/mo in sewer fees will see those bills increase to over $37/mo by 2014. Subsequent rate increases could force rates to rise to over $50 per month by 2017.
Generally, there should be no direct costs assessed to individuals’ homes or businesses where new sewers are constructed.
|2009 CSO Brochure||1.06 MB, PDF|
|2010 CSO Brochure||3.36 MB, PDF|
|2011 Sewer Use Charges Brochure||2.00 MB, PDF|
|2012 Sewer Use Charges Brochure||1.74 MB, PDF|
|Commercial and Industrial Users Presentation||1.7MB PDF|
|Community Presentation on the Long Term Control Plan||2.7MB PDF|
|Commercial and Industrial Users Presentation||1.7MB PDF|
Urban Design Handbook for Omaha - The Green Streets Plan for Omaha serves as a guide for design and planning of designated the "green streets" system throughout Omaha. The plan includes an analysis of Omaha's existing streets, a map of the green streets system, design prototypes and details and implementation measures for the plan. This document shall act as the primary guide for right-of-way improvements which supersedes the Standards for Urban Landscaping.
Omaha Streetscape Handbook - The Omaha Streetscape Handbook serves as a guide for design and planning of streetscape components within right of way. The handbook includes descriptions of individual component, minimum performance standards and design considerations. It has been adopted as part of the Urban Design Element of the Omaha Master Plan.
Standards for Urban Landscaping - The Standards for Urban Landscaping is a legacy document pertaining to urban landscaping. It is generally suitable as a reference for information not covered by subsequent standards or guidebooks as applicable to private property.
Old Market and Wholesale District Guidelines - Design guidelines for all buildings and areas within the Old Market Historic District. In some cases these standards may apply to publically funded development adjacent to the district. Consult with the City Planning Department for applicability.
Omaha Master Plans
Green Streets Plan for Omaha
The Green Streets Plan for Omaha serves as a guide for design and planning of designated the "green streets" system throughout Omaha. The plan includes an analysis of Omaha's existing streets, a map of the green streets system, design prototypes and details and implementation measures for the plan. This document shall act as the primary guide for right-of-way improvements which supersedes the Standards for Urban Landscaping.
Green Streets Plan - Part 1 Analysis (pages 1 - 50)
Green Streets Plan - Part 2 Prototypes, details and tree species (pages 51 - 112)
Green Streets Plan - Part 3 Implementation (pages 113 - 127)
|CSO Display||178k, PDF|