A report released yesterday by American Whitewater finds that the flows mandated for the Saranac River's High Falls Gorge will likely fail to restore basic ecological functions to the river. The flows were mandated by the State of New York based on a flow assessment method known as the "delphi habitat assessment." The report critiques the mandated flows using an analytical method developed by the Nature Conservancy that compares human caused changes in certain aspects of flows that are ecologically important. The report shows that:
1) the Saranac River is likely to remain severely impaired for the 40 year term of the dam license,
2) the delphi habitat assessment failed to produce defensible results, and
3) the Nature Conservancy method excels at analyzing flow prescriptions.
The report compares two data sets 1) 50 years of natural flows in the Saranac River, and 2) 50 years of future managed flows based on the flow mandate. The IHA method compares these two data sets as though the river flowed naturally for 50 years and then suddenly the mandated flows were implemented. On many of the graphs in the report, the natural flows are green and the managed flows are red. Even the casual observer of these graphs can grasp the significant departure from natural flows that the managed flows represent.
This report is an important document for the paddling community for several reasons. Many agencies rely on flow prescription methods that only address base flows in rivers. The Nature Conservancy method, called Indicators of Hydrologic Alteration (IHA), addresses ecological values of the full suite of natural flows including low flows, various pulse flows, and various sizes of floods. American Whitewater is interested in encouraging the use of IHA to restore flow regimes to rivers that provide a full range of flows, with which come a full range of ecological and recreational values. The report offers one example of how IHA can be used to analyze and prescribe flows that do just this.
The objective scientifically-based IHA tool also showed that the subjective opinion-based delphi method failed to produce consistent results. In fact, the State of New York opposed low pulse flows (based on the delphi method) that IHA suggests would have restored ecological functions to the Saranac River. AW has an interest in assuring that only scientifically defensible methods are used to prescribe flows. In this case, because of a poor choice of methods, restoration opportunities were missed.
With this report AW hopes to add to the body of literature supporting science-based flow prescriptions that result in efficiently and effectively restored rivers.
The report can be downloaded and read through the "Documents" box to the right of this article.
American Whitewater's detailed critique of the mandated flow regime for the Saranac River and the methods that lead to it, using the Indicators of Hydrologic Alteration tool.