Subject
- Stream ecology3
- Water -- Pollution -- Oregon -- Willamette River3
- Agriculture -- Economic aspects -- Mathematical models2
- Aspen -- Ecology -- Yellowstone National Park2
- Climatic changes2
- Fishes -- Habitat -- Oregon2
- Forage plants -- Oregon2
- Groundwater recharge2
- Land use -- Oregon -- Willamette River Valley2
- Plant communities -- Oregon2
- Snow -- Cascade Range2
- Stream chemistry2
- Water resources development -- Northwest, Pacific2
- Water rights (International law)2
- Water-supply -- Columbia River Watershed -- Management2
- Water-supply -- Management2
- Agricultural chemicals -- Environmental aspects -- Oregon -- Willamette River Valley1
- Agricultural pollution -- Oregon1
- Agricultural wastes -- Environmental aspects1
- Agriculture -- Oregon -- Willamette River Valley1