Lower Willamette STEP - The Lower Willamette STEP district covers the lower Willamette basin including the Portland Metropolitan area. Major stream basins include the Clatskanie, Tualatin, Yamhill, Molalla/Pudding, Clackamas, Sandy and lower Willamette Rivers.
Mid-Willamette STEP - The Mid-Willamette STEP district covers the mid-Willamette basin from Eugene north to Salem. Major stream basins include Rickreall Creek, and the North Santiam, South Santiam, Calapooia, Luckiamute, Marys, Long Tom and mainstem Willamette Rivers.
Upper Willamette STEP - The Upper Willamette STEP district covers the headwaters of the Willamette River including the McKenzie, Middle Fork Willamette and Coast Fork Willamette Rivers.
North Coast STEP - The North Coast STEP district includes all of the coastal basins extending from Neskowin Creek (Cascade Head) north to the Columbia River, and the lower Columbia River tributaries from the mouth up to Plympton Creek (Westport). Major stream basins include the Klaskanine, Youngs, Lewis and Clark, Necanicum, Nehalem, Kilchis, Wilson, Trask, Tillamook and Nestucca Rivers.
Mid-Coast STEP - The Mid-Coast STEP district includes all of the central Oregon Coast basins from Salmon River south to Siltcoos and Tahkenitch Lakes near Reedsport. Major stream basins include the Salmon, Siletz, Yaquina, Alsea and Siuslaw Rivers.
Umpqua STEP - The Umpqua STEP district covers the entire Umpqua Basin and extends from Diamond Lake in the Cascades west to the coast at Reedsport. Major stream basins include Cow and Calapooya Creek, and the North Fork, South Fork and mainstem Umpqua River.
Tenmile, Coos and Coquille STEP - The Tenmile, Coos and Coquille STEP district covers the Oregon Coast basins from the Eel/Tenmile Lake area south to Bandon. Major stream basins include the Tenmile Lake area, and the Millicoma, Coos and Coquille Rivers.
Lower Rogue STEP - The Lower Rogue STEP district covers the southern Oregon Coast from Four Mile Creek near Bandon south to the California boarder. Major stream basins include the Sixes, Elk, Pistol and Chetco Rivers, the lower Illinois River and the lower mainstem of the Rogue River from the mouth upstream to Mule Creek.
Upper Rogue STEP - The Upper Rogue STEP district covers all waters n the Rogue Basin upstream of the mainstem tributary of Mule Creek to the headwaters near Crater Lake. Major stream basins include the upper Illinois, Applegate and Rogue Rivers.
Eastern Oregon STEP - The Eastern Oregon STEP district covers the entire state east of the Cascades and includes 18 counties with nearly 67,000 square miles. Major stream basins include the Deschutes, Klamath, Chewaucan, Silvies, Donner and Blitzen, Malheur, Owyhee, John Day, Umatilla, Grande Ronde and Powder Rivers.