The United States lies between the Atlantic and Pacific Oceans in the temperate zone on the continent of North America. It has a favorable geographic position and vast natural resources. Generally, management of water resources is characterized by professional competence. The western United States is generally dry with a Mediterranean climate in California, further north in California, Oregon, and Washington, on the western coast there is an oceanic climate. The areas at low elevation further east are in the rain shadow of the Sierra Nevada and Cascade Mountains. Generally, in this area water is scarce, with cultivation possible only by use of irrigation.
It is only east of the Rocky Mountains on the Great Plains that natural rainfall is sufficient to grow crops, with only dryland farming possible in the western portion without irrigation. It is in this area that there has been great reliance on ground water, particularly, the Ogallala Aquifer. The eastern United States is generally well-watered, but experiences occasional drought. Dense urbanization in this area has resulted in difficult to fulfill demands on water resources, as it has in Los Angeles and other urbanized areas in the desert Southwest.
- Climate, geography, demography, and water resources of the northeastern United States
- Climate, geography, demography, and water resources of the southeastern United States
- Climate, geography, demography, and water resources of the southwestern United States