Region
- United States 20 results
- Africa 12 results
- Arizona 6 results
- California 6 results
- Colorado River (Colo.-Mexico) 6 results
- Developing countries 6 results
- Grand Canyon 6 results
- Grand Canyon (Ariz.) 6 results
- Israel 6 results
- Middle East 6 results
- Pacific Area 6 results
- Asia 4 results
- China 4 results
- Jordan 4 results
- Jordan River Valley 4 results
- Afghanistan 2 results
- Africa, North 2 results
- Africa, Southern 2 results
- Africa, Sub-Saharan 2 results
- Atlanta 2 results
- Atlanta (Ga.) 2 results
- Brahmaputra River 2 results
- Brahmaputra River Watershed 2 results
- California, Northern 2 results
- Canada 2 results
- Caribbean Area 2 results
- Carmel River Region 2 results
- Congo River 2 results
- Congo River Watershed 2 results
- East Asia 2 results
- England 2 results
- Europe 2 results
- Everglades National Park (Fla.) 2 results
- Florida 2 results
- Gaza Strip 2 results
- Georgia 2 results
- Hetch Hetchy Valley (Calif.) 2 results
- Kenya 2 results
- Lesotho 2 results
- London 2 results
- Mexico 2 results
- Mexico City 2 results
- Mexique 2 results
- Nile River Watershed 2 results
- OECD countries 2 results
- Palestine 2 results
- San Francisco Bay Area 2 results
- South Africa 2 results
- Spain 2 results
- Texas 2 results more…