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Project Details

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Project Information Sheet

Field evaluation of on-site sewage disposal systems (OSDS) and broad-scale mapping of suitable and unsuitable areas for OSDS, Morgan County, Indiana

Funding Source:	Indiana State Department of Health
Period of Contract:	1 Oct 2003 to 30 Sep 2005
Status:	completed — Definition of status type
Project Director:	Greg A. Olyphant and Sally L. Letsinger

Issue

More than 800,000 on-site sewage disposal systems exist in Indiana; evaulating nitrogen loading of aquifers is important so the state can make informed management decisions concerning the suitability of on-site sewage disposal systems in different landform and soil settings. Many citizens of Morgan County use on-site sewage disposal systems (OSDS) as their primary method of wastewater treatment. These systems can be cost-effective and efficient methods of treating wastewater if they are properly designed and installed. However, some areas of Morgan County may not be suitable for these systems. Potential water-quality degradation is a public health concern because of the increased possibility for transmission of waterborne diseases in contaminated drinking water.

Objective

The objective of this project was to collect data concerning the subsurface ground-water characteristics that exist in and adjacent to on-site sewage disposal systems throughout the entire year.

Approach

As a pilot effort in addressing this issue, Morgan County, Indiana, with its wide range of soils and topographic settings, was selected for intensive site-specific investigations and geographic information system (GIS) analysis. We monitored in and beneath septic distribution fields at each of four field sites. The sites selected were different from one another in setting and soil texture, and were representative of a broad range of soil types within Morgan County. Each site was monitored for 10 months.

Products

The results of the monitoring were used to calculate rates at which nitrogen was recharging into ground water. These loading rates and their relationship to topographic and geologic factors were subsequently used to guide a GIS analysis of Morgan County and to derive a preliminary map showing various degrees of OSDS suitability.

Benefits

Research-based recommendations were provided to the Indiana State Department of Health regarding the suitability of on-site sewage disposal systems in Morgan County. The methodology developed for assessing the suitability of OSDS can be applied to other areas of the state.

Locations Affected:

Morgan

Indiana House Districts Affected:

47

93

Indiana Senate Districts Affected:

35

37

Indiana Congressional Districts Affected:

Information Updated February 1, 2007

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