The Hydrogeology of an Old Growth Forest with Implications for Defining Impact Zones Associated with Underground Mining
Dysart Woods is a predominantly oak and hickory old-growth forest that was given to Ohio University by The Nature Conservancy for research and public use. After a long discussion in the government and against the desires of the environmental organizations that opposed mining in the vicinity of this forest, a permit was issued and the Dysart Woods watershed is being undermined via longwall mining methods and the old-growth forest areas are being undermined via room-and-pillar mining methods. Buffer zones based upon the angle of influence have been placed around Dysart Woods to protect it from the influence of longwall mining. While this concept is sufficient for architectural structures it was not designed to prevent changes in hydrogeologic properties that typically accompany underground mining. The purpose of this work is to assess hydrogeologic impacts in a watershed context beyond the recharge area delineated by a buffer zone that has been determined by the angle of influence. Results of the physical model show that the water table elevations of the northeast portion of the water table of the shallowest aquifer underneath the Dysart Woods watershed have lowered as a result to longwall mining. Results of transient numerical modeling show a decline in the calculated heads from pre-mining head elevations to post-mining head elevations inside the buffer zone proposed by the mining company. The transient simulation was modeled to 12/1/2014, which showed that the upper hydrostratigraphic units dried up as a result of underground mining. If perching layers do not recover with time, this could have detrimental effects on Dysart Woods. This suggests new considerations for underground mining regulations with respect to preserving ecosystems that are dependent on groundwater systems. In particular, the groundwater system protection zone should be defined on the basis of watershed-scale hydrology as opposed to buffer zones based on the angle of influence.
School Location:USA - Ohio
Source Type:Master's Thesis
Keywords:hydrogeology impact zones perched aquifers old growth forest dysart woods
Date of Publication:01/01/2008