Subject
- Water resources development -- Oregon21
- Water resources development -- Oregon -- Willamette River Valley10
- Water-supply -- Oregon9
- Soil conservation -- Oregon -- Willamette River Valley8
- Upper Willamette Resource Conservation and Development Project8
- Forest management -- Oregon5
- Natural resources -- Oregon5
- Water conservation -- Research -- Oregon5
- Regional planning -- Oregon4
- Water resources development -- Oregon -- Congresses4
- Water resources development -- Oregon -- Willamette River Watershed4
- Forest management -- Oregon -- Willamette River Watershed2
- Information storage and retrieval systems -- Water resources development2
- Natural resources -- Oregon -- Willamette River Watershed2
- Regional planning -- Oregon -- Willamette River Watershed2
- Tillamook Bay National Estuary Project (Or.) -- Electronic information resources2
- Tillamook Bay Watershed (Or.) -- Geographic information systems2
- Water use -- Oregon2
- Watersheds -- Oregon2
- Watersheds -- Remote sensing -- Oregon -- Tillamook Bay2