Stream Impacts from Water Withdrawals in the Marcellus Shale Region
The study is the first region-wide assessment to document “flow-ecology” relationships – showing connections between observed impacts under current water withdrawal standards (based on daily water gauge data collected over the last 15 years and fish surveys) and the decline in freshwater fish communities.
View key findings, data, and final report.
The study recommends regulating flow standards from water withdrawal based on stream size and season, which could provide critical information to help resource managers, industry and others make more informed decisions in achieving sustainable river and stream flows that balance the needs of society and healthy ecosystems.
In addition to considering the cumulative impacts of water withdrawals, as one example, the researchers looked at specific impacts of large water withdrawals with hydraulic fracturing in the Marcellus Shale region. The study attempts to answer these key questions:
- What are the observed impacts of water withdrawals on freshwater fish communities and ecosystems associated with current levels of water withdrawals?
- What might those impacts look like under a range of potential water withdrawal scenarios?
- Is it possible, using sophisticated computer modeling techniques, to identify different flow regimes that deliver a more balanced approach for regulating water withdrawals to meet human demands and sustain healthy ecosystems?
Based on the assessed relationships and factors such as season, stream size, and projected expansion of natural gas development in the region, scientists developed models showing how water withdrawals impact sustainability of aquatic ecosystems. Cornell researchers also applied a model to vary water withdrawal scenarios – for example from current standards to a more seasonally variable scenario – that provided critical information on how flow regimes can be modified to achieve a balance in meeting both human/energy water needs and those required to maintain healthy ecosystems and diversity.
Key findings and recommendations from the research include:
- Flow-ecology relationships indicate fish are sensitive not only to changes in low flows, but also to changes in a variety of flow components (season, median, and high flows). This has important implications for setting sustainable flow standards and designing monitoring campaigns.
- A considerable number of streams are at high risk of flow alteration due to withdrawals during the summer and fall seasons – especially smaller streams in the southwestern (western portions of Ohio River Basin) and northern (headwaters of the Upper Susquehanna and Hudson River Basins) sections of the region.
- Though these high-risk streams are individually small, combined they drain the majority of the study region.
- Fixed minimum aquatic flow standards that do not consider seasonal changes in flows and throughout the year may not be adequate to sustain fish populations and aquatic biodiversity.
- But a balance can be realized if flow standards due to water withdrawal regulations vary with stream size and season and thus provide the necessary balance between human needs and flows needed to sustain fish and aquatic ecosystems.
This research underscores the Appalachian LCC’s role as a science-driven forum for partners to identify regional conservation priorities and develop information and tools that help people make informed decisions about land use that will help sustain important natural resources. For more information about the findings and recommendations from the research including access to the final report and data, view: http://applcc.org/research/stream-impacts-water-withdrawals.
