ABSTRACT:

Hydrological, biological, and geomorphological dataset collected from the Pacific Northwest (PNW = Oregon, Idaho, and Washington) used to develop the Oregon (OR) Streamflow Duration Assessment Method (SDAM) and the PN SDAM. SDAMs are rapid, reach-scale indices or models that use physical and/or biological indicators to predict flow duration class. Three flow duration classes are used in the OR and PNW SDAMs: perennial, intermittent, and ephemeral. Perennial reaches have continuous surface flow and do not experience drying outside of extreme drought. Intermittent reaches have continuous surface flow for part of the year that is sustained by snowmelt and/or groundwater. Ephemeral reaches have surface flow only during and immediately following precipitation or snowmelt