The development of Southwest Virginia’s coal mining region is limited by a lack of building sites. Much of the land in this region consists of steep slopes with shallow soils that are poorly suited to residential development. In recent years, widespread surface coal mining has created landforms that are favorably located and configured to support residential housing. However, because such sites are commonly located beyond the extent of public sewers, developing them requires a means for on-site wastewater treatment and dispersal. This publication is written for homeowners, homebuilders, land developers, public officials, and others who may have an interest in building residential housing or other types of development on mined lands that are not accessible to public sewers.

Wastewater is a significant source of carbon, sediment, nutrients, pathogens, and other potential pollutants. Reducing the quantity of these contaminants before they are discharged to either groundwater or surface water is essential to preserve or enhance water quality in receiving waters. This is accomplished through the installation of wastewater treatment and collection systems. The form of these systems can vary substantially. In Virginia, they range in size from 5,000 to 50,000 gallons per day; 49 percent are public systems and the remainder are private (Parten 2008).

The purpose of this document is to provide guidance on measuring water movement through in situ saturated soil (saturated hydraulic conductivity, or Ksat) as it relates to dispersal and treatment of on-site sewage (wastewater) through an on-site wastewater dispersal area