Opinion Graphic
The Appalachian Mountains span most of the Eastern United States and are home to many functional and culturally important species, as well as coal mining operations.
A common method of coal mining is mountaintop removal, a process in which the top portion of a mountain is fractured and moved into the adjacent valley to gain access to horizontal coal seams. The fragmented mountain rock (mining spoil) often buries headwater streams, the originating source of streams that merge to become larger rivers downstream.
Therefore, the quality and quantity of water at the headwaters plays a large role in downstream water quality and quantity; the systems are interrelated. Because water generally flows from high to low elevation, most streams originate in the mountains; consequently, most headwaters are also found in the mountains.
Headwaters are functionally important in controlling the paths that streams follow, the length of time for pools of water to refill, and the length of time for water to remain in pools, for example, groundwater and reservoirs. Some headwaters contribute as much as three-quarters of average annual water flow.
Water that flows vertically into the ground and is stored below the land is called groundwater, which supplements rivers year-round and provides a greater fraction of the river’s flow during droughts.
Some studies have looked at how mining has altered the fraction of precipitation that flows into the ground, flows overland into tributary streams, or evaporates into the atmosphere. Removing vegetation from mining sites and compacting soils have decreased rates of water flowing into the ground and led to more water flowing overland.
In places like heavily urbanized landscapes, more water flowing overland increases the likelihood of downstream flooding after precipitation events, and less water absorbed by the ground. Placing mountain spoils over headwaters has also shown an increased concentration of metals leaching into streams, decreased health of stream organisms, and persistent sulfate pollution. Stream health has become increasingly degraded near mining sites and downstream.
Therefore, mining companies, regulators, and the pertinent fields of scientists should come together to comprehensively research the effects of mountaintop removal on overall stream health (both changes in water quality and quantity). This would enable them to create policies that allow coal mining in such ways that the stream environments are less likely to become degraded. It would allow downstream public utilities to make informed decisions with science-based knowledge of future water supply quality and quantity.