HRWC and a team of researchers and public health managers studied a new method for detecting failed septic systems to reduce pollutants entering the Huron River and yield a cost-effective approach for county health departments to monitor and rectify problem septic systems.
The 3-year study tested the use of color, infrared and thermal aerial photography to predict the functional status of septic systems. The intent was to use the information to help homeowners correct failing septic systems (or extend the life of those functioning well) by providing specific recommendations and information on proper operation and maintenance.
What is the Problem with Septics?
Pollutants from failing septic systems — pathogens and phosphorus — play a role in the health of the Huron River and its tributary streams located in rural areas. In fact, one of the more perplexing questions about water pollution in this river has been “how much of a problem are failing septics?” Preliminary work by HRWC and others shows that, potentially, the highest concentrations of phosphorus entering the middle Huron (where a TMDL mandates phosphorus reduction) are from failing septic systems.
Septic systems are essential to rural living. Communities have standards for their design, construction, and, increasingly, maintenance. Yet, even with those standards, septic systems can fail. When a septic system fails, the polluted water it releases can pose a human health risk, an expensive repair and a water quality problem for groundwater, streams and lakes.
Years 1 and 2 focused on developing a method to determine septic system failure probability by analyzing digital imagery along with existing county septic system records, taking weather and seasonal conditions into consideration, and conducting site visits to field verify the research. The task was to identify unusual patterns in vegetation (failure signatures) that could be attributed to leaking septic systems. A leaking or failing septic saturates the surrounding soil with nutrients and water which can lead to unusually vigorous vegetation growth or die-off. Report describing the methodology employed available HERE (pdf).
In Year 3 HRWC designed, implemented and assessed a homeowner education campaign that used the information learned during the earlier part of the project. The following resources were direct mailed to residents of the study area and incorporated into HRWC’s web resources on septic systems:
- “Would You Know If Your Septic System Needed Surgery?” brochure developed by the project team.
- “Do Your Part – Be SepticSmart” brochure provided by EPA.
Some homeowners were also provided with their septic system’s specific individual risk categorization. Report describing outreach efforts in detail and the results of a post outreach evaluative survey available HERE (pdf).
The project leveraged HRWC Middle Huron monitoring already underway to capture any water quality changes at a larger subwatershed scale, but then also added targeted E. coli sampling and biological source tracking (BST) at almost 30 sites across the two focus catchments: Mill and Honey creeks.
The resulting data indicated that bacterial contamination was widespread throughout the Honey Creek watershed, but especially concentrated in three areas: two branches flowing from south of Jackson Road that come together near Staebler Road; a small branch that runs under West Delhi Road; and a branch that runs west along Miller Road. Bacteria from dog, bovine and human sources were detected.
Mill Creek was shown to be consistently high in E. coli with no specific “hot spot” branches. Genetic markers were found for all five potential biological sources, so no distinct source (human or otherwise) could be identified in any Mill Creek branch.
Saving money and improving water quality were the main drivers of this project. Could the project team use an innovative approach to detect at-risk failing septics and provide a cost-effective approach for resource-limited county health departments? The project overall determined that using aerial image analysis to identify at-risk properties is a viable approach when coupled with strong supporting data such as installation permit records and/or time-of-sale inspections and recommendations. The method requires refinement, including improved supporting data and more information on how failing systems are revealed by impacts to surrounding property.
Contact Project Manager Elizabeth Riggs for more information.