For years, the common method of disposing of trees and stumps when land was being developed was to pile and burn off the material. This practice was banned in 1968. Thereafter, developers went in another direction getting rid of the material: they buried it. This common practice carried on until 1988, when burying wood debris was prohibited. Unfortunately, some 25 years after burying debris was banned, sinkholes have begun appearing where wood debris was buried in the late 1960s, 70s and 80s.
Commonly known as debris pits, these sinkholes pose several threats to human health. First, they can literally open up, creating voids in the ground that can drop many feet down. These voids are sometimes narrow and devoid of oxygen, making them difficult to escape and potentially lethal. If structures have been built over debris pits, the settling of debris under it usually leads to significant and sometimes severe structural damage. Another perilous outcome is methane produced by decaying wood, which means the debris pits host concentrated pockets of methane that pose obvious health hazards.
There are three indicators to look for if you suspect a debris pit on your property:
- Subsidence – an area of the yard that has settled and is lower in elevation than what surrounds it. The difference in elevation can be a few inches to a couple of feet depending on the amount of settlement that has occurred. Cracks in the soil at the edge of the subsided area may be visible. The natural settlement and decomposition of the waste mass cause subsidence. Subsidence can also occur in areas where soils used for fill have not been properly compacted.
- Distressed vegetation – plants and grass will not grow, or else grow poorly in a specific area as a result of gases produced by the decomposing debris. While this is one possible indication of a debris pit, distressed vegetation can be caused by other many factors.
- Sinkholes – an open hole or holes that suddenly appear in your yard. Sinkholes may appear small at the surface but can be cavernous immediately below the ground’s surface and should be approached with caution. As a safety precaution, sinkholes should be covered with plywood or a suitable substitute and children should be kept away until the cause of the sinkhole can be determined and the problem corrected. Sinkholes are formed when large void spaces within the buried debris become exposed at the surface of the ground. The debris within the debris pit is sometimes visible within the sinkhole. Sinkholes can also be formed by improperly channeled storm water or by abandoned septic tanks that have degenerated.
The State of Delaware and New Castle County have dedicated funding to remediate debris pits. If you believe you have a debris pit, both can assist you in determining the best course of action.
Division of Watershed Stewardship Debris Pit Remediation Program
2430 Old County Road
Newark, DE 19702
Debris Pit Complaint Form (MS Excel)
Here is a summary of your options for addressing a debris pit on your property:
- Option 1: Do it yourself
As long as you or your contractor complete the work according to state program specifications, and the work has been monitored by the Division of Watershed Stewardship program staff, you may be eligible to receive up to $10,000 in reimbursement payments. Documentation of costs are required.
- Option 2: New Castle County Conservation District cost-share program
The New Castle County Conservation District will remediate debris pits whose owners are willing to contribute 25 percent of the cost of the project out of pocket (up to $40,000; 10 percent of costs in excess of $40,000). Work will begin almost immediately.
- Option 3: State program
The State will remediate debris pits free of charge. However, there is a waiting list. There are currently close to 300 properties on the waiting list, which equates to a waiting list of seven years before work will begin.