Alternate systems for environmentally vulnerable areas

Some areas in Nebraska are not appropriate for a conventional septic tank/drainfield system or a residential lagoon. We consider these environmentally vulnerable areas.

Some soils may accept water too slowly, so that sewage may pond on the soil or back up into the house if a conventional system is used. Some areas, especially those with high groundwater levels or in close proximity to surface water, are extremely sensitive to pollution. Examples include wetlands or areas near lakes, rivers or streams. These vulnerable areas are very important to protect since groundwater is an important source of drinking water, surface water provides excellent recreational opportunities and is important for wildlife as well.

Mound systems are one of a number of alternative systems that have been developed to overcome site conditions that limit the use of a conventional drainfield, including soils with slow or fast permeability, shallow soils over bedrock or a high water table. A mound system creates suitable conditions for treatment above the natural soil surface.

A constructed wetland is another type of system that is sometimes used in place of a residential lagoon, where the soil has very slow permeability. A wetland is designed and created to mimic processes in a natural wetland. The specific design allows a constructed wetland to treat sewage, while a natural wetland would become polluted by the sewage.

Presently, a mound system or constructed wetland must be designed by a professional engineer. The plans must receive approval from the Nebraska Department of Environmental Quality before construction can begin. A certified installer, professional engineer, or registered environmental health specialist can then install the system.

Careful lakeside development and wellhead protection are some of the tools that can help protect surface water and groundwater. For more information access the Extension publications listed below and see the related pages within this website on:

• Lakeside development
• Wellhead protection
• Toxic algae

UNL Extension Publications

Constructed wetlands

Mound systems

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Information presented within the onsite wastewater treatment section of this Water Web site has been reviewed by Wayne Woldt with the University of Nebraska–Lincoln Onsite Wastewater program.