Mitigating Unwanted Ponds (IMAGE) University of Pittsburgh Caption Subsidence can sometime result in planned ponding of streams. The permit process requires that these events be identified prior to mining and that interventions be developed to mitigate the ponding events. For example, the ponding of water in the field was mitigated by draining the water, followed by re-grading. After these mitigation efforts, the field is returned to its pre-mining condition. Credit Anthony Iannacchione/University of Pittsburgh Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.