Filling the hole Sinkholes on Commercial Before you begin repairs, an evaluation needs to When solid rock is encountered near the surface omit be conducted to ensure that utility lines and sep- the bottom most layers (that is start with a smaller Industrial & tic systems are not affected. The Health Depart- stone size) or use thinner layers. It is important that ment may be able to assist. the bottom layer be larger than the solution channel Residential opening in the bedrock. The objective is to provide an open path for percolating water so that it cannot Property carry away soil and cause another sinkhole. The re- pair, as described, also provides good filtration of water.
Fixing the structure
The County will determine if the structure is safe enough to use. If you are advised not to enter the structure, you should comply.
Your insurance agent will advise you regarding your coverage and options.
A sinkhole is best repaired by excavating to rock Damage to structures will require an expert to evalu- then building an aggregate filter in the hole, how- ate the situation. You may want to contact a com- ever, our area has little rock. pany that does foundation repairs.
1. Excavate the sinkhole down to rock if possi- ble. Remove stumps and debris. Fixing the driveway or yard 2. Put a layer of large stones in the hole (cabbage size). The hole affecting the driveway will need to be repaired 3. Put a layer of smaller stones on top (fist before you can fix the driveway. size). 4. Put a layer of gravel on top of the small A sinkhole caused by a leaking or damaged drain, pipe stones. or culvert cannot be repaired until the situation that 5. Cover the gravel with a geotextile fabric. cause the sinkhole is resolved. This may affect more This prevents the next layer (sand) from be- than one property owner. These situations are difficult ing lost through the gravel. to resolve and may required legal assistance. 6. Cover the geotextile fabric with a layer of coarse sand. Where can I get more information on sinkholes? 7. Fill the remainder of the hole with soil. This Onslow County Emergency Management: Call during can be layered to match the existing soil pro- file. working hours: (910) 347-4270 or on the web: Ideally each layer is six inches to two feet thick. http://www.onslowcountync.gov/ What do I do when I discover a sinkhole on my property?
• First and foremost: • If a public road is involved, contact the What does a sinkhole have to Ensure that life and property are local law enforcement authorities. They do with the groundwater safe. If a structure is involved and will help to secure the area. there appears to be structural supply? damage—vacate the building • Document with photographs. immediately and stay away until it Surface water that enters a sinkhole is examined. • Contact your insurance agent if passes directly into the groundwater structures are involved. with minimal filtration. In addition, • Move vehicles and equipment. waterborne contaminants that enter a • Continue to observe the sinkhole for sinkhole may be transported at a very • Secure the area with a fence, rope signs of enlarging, especially toward high rate of speed, meaning that they or tape. Keep children out of the structures, septic system drain fields, enter the groundwater quickly. area. waterlines, wells, buried tanks, and buried utility lines. This can be done by Do not put anything in the sinkhole • Contact the Onslow County using a thin metal or fiberglass rod that except for what is advised by experts. Emergency Management Center is pushed into the soil. Areas near the A sinkhole is not a dump. The water during normal business hours at sinkhole will offer less resistance to the supply or aquifer you contaminate (910)347-4270 They investigate rod than unaffected soil. Be aware of might be yours! all sinkholes that develop in the buried power lines when using a metal county and will further advise you rod! Do not apply fertilizer, pesticide or as to the type of sinkhole involved. other chemicals near the sinkhole.
Sinkholes • Soil in and near an active sinkhole Direct water away from the sinkhole. can collapse without warning, so This may help keep it from getting lar- Primarykeep Businessa good Address distance away from ger. One way to do this is to create a Your Address Line 2 berm that is seeded with Bermuda or Yourthe Address opening. Line 3 You will be held Yourliable Address if Lineanyone 4 is hurt on your Fescue grass. property, so take proper precautions to secure the area.