Improved Sinkhole

{
  "id": "MLC-T-ENV-013938",
  "term": "Improved Sinkhole",
  "field": "Environment",
  "definition": "1. A naturally occurring karst depression or other natural crevice found in volcanic terrain and other geologic settings which have been modified for the purpose of directing and emplacing fluids into the subsurface.\n\n2. An improved sinkhole is defined in the Code of Federal Regulations Section 144.3 as a naturally occurring karst depression or other natural crevice found in volcanic terrain and other geologic settings which have been modified by humans for the purpose of directing and emplacing fluids into the subsurface. In Region 5, sinkholes are commonly funnel-shaped depressions in the land surface generally in a limestone (karst) regions. They allow water to flow directly from the surface into the ground water through passages in the rock created by solution. Water entering the ground water in this fashion does not go through any of the natural purification processes that happen when it flows through soil.\n\n3. Naturally occurring karst depression or other natural crevice found in volcanic terrain and other geologic settings which have been modified by man for the purpose of directing and emplacing fluids into the subsurface. [40 CFR 144.3 (CFR 2018)]",
  "subject": "Land, waste and cleanup",
  "references": [
    "Underground Injection Control Glossary",
    "Underground Injection Control Terms",
    "40 CFR 146.3 (CFR 2018)"
  ],
  "url": "https://mlchart.com/terminology/environment/improved-sinkhole/"
}