The Oregon dunes of the Siuslaw National Forest comprise a stunning landscape, spanning nearly 40 miles of the Oregon coast. Like sand dunes elsewhere, this landscape harbors a great quantity of fresh groundwater, soaking up rainwater as it falls. The numerous freshwater wetlands and lakes scattered within the dunes are a surface expression of the dunal aquifer and harbor many species and communities that are dependent on this water (also referred to as groundwater-dependent ecosystems, or GDEs).

This groundwater resource, however, also supplies some of the water needs of local coastal communities. The Coos Bay-North Bend Water Board has a water right to pump groundwater from the sand dune aquifer to meet municipal and industrial uses. Our work in partnership with the US Forest Service is intended to develop recommendations for water use in order to address the following management question: What rate, distribution, and timing of groundwater pumping can be supported by the sand dune aquifer while also supporting the groundwater dependent lakes, wetlands, and species?

These Environmental Flows and Levels will depend on local climatic, hydrologic, geologic, and ecological conditions. Based on projects in other national forests, we have developed a framework for conducting the research necessary to determine environmental flows and levels.

In this pilot project, we will be applying similar methods in order to assist the Forest Service with managing their special-use permit . By developing ecologically-based limits to water withdrawal in the Oregon dunes landscape, future water needs can be evaluated against risk to important ecosystems and species. Photo credits clockwise from top left: Leslie Bach; all others, Emilie Blevins

For more information:

Allison Aldous Leslie Bach [email protected] [email protected] 503-802-8142 503-802-8146

The Nature Conservancy in Oregon, 821 SE 14th Ave, Portland, Oregon, 97214