Hydraulic analysis is of particular concern for the review/approval of sites handling large flows, as well as for smaller flows when substantial reduction in field size is proposed, or where reductions are proposed in vertical and/or horizontal setback distances, typically in conjunction with the use of advanced pretreatment. Another important area where hydraulic analysis is of growing importance is when water level monitoring is proposed as a substitute for determining depth to a soil wetness condition. These monitoring data can be most accurately evaluated in conjunction with a detailed hydraulic analysis of the site. Also, when drainage is proposed, especially for finer than Group II soils, an hydraulic analysis is necessary for the proper evaluation of the proposed drainage system's effectiveness. As concerns about the pollutant contributions of subsurface systems to ground and surface water degradation increase, so will the need for more refined hydraulic analyses. Before any attempt can be made to predict contaminant transport rates away from a wastewater system, the site's key hydraulic parameters must be accurately determined.

This presentation includes an overview of:

1) Why hydraulic analyses are needed, and when they are required within the context of North Carolina's on-site wastewater program.
2) The various approaches to performing hydraulic analyses and their applicability under differing circumstances. This includes field evaluation and data collection, such as K_sat measurements, and data evaluation tools.
3) Differences by North Carolina Region in situations where hydraulic analyses are needed, and special considerations which are applicable by Region.
4) Potential changes in hydraulic analysis requirements and needs.
5) How the hydraulic analysis can be utilized as a basis for design/approval decisions.

Please address any questions to Dr. David Lindbo.

This page created by
Roland O. Coburn, Research Technician I on 1/10/03.