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The Hydrologic Cycle

H2O Cycle Image

The hydrologic cycle begins with the evaporation of water from the surface of a body of water such as the ocean. Condensation occurs as water vapor rises through the atmosphere, cools and form clouds. Moisture is transported around the globe until it returns to the surface as precipitation. Once the water reaches the ground, one of three processes occurs: 1) some of the water may evaporate back into the atmosphere, 2) the water may infiltrate the surface and become groundwater or 3) the water accumulates on the earth's surface as ponds or lakes. Groundwater either seeps to streams, rivers, and oceans or rises back into the atmosphere through transpiration. The balance of water that remains on the earth's surface is runoff, which flows into streams, rivers, lakes and eventually oceans, where the cycle begins again.

Contact Information

Director, Public Works and Utilities
Dan St. John, F.ASCE
202 N. McDowell Blvd
Petaluma, CA 94954
Phone: 707-778-4546
Fax: 707.206.6034
Email: dstjohn@ci.petaluma.ca.us

Administrative Offices
202 North McDowell Blvd.
Petaluma, CA 94954
Phone: 707.778.4546
Fax: 707.206.6034
Email: water@ci.petaluma.ca.us
Hours: 8:00 A.M. - 5:00 P.M.
Monday - Friday

Utility Billing
11 English Street
Petaluma, CA 94952
Phone: 707.778.4350
Hours: 8:00 A.M. - 5:00 P.M.
Monday – Thursday

Water, Sewer, or Storm Water Emergency
Phone: 707.778.4546

Water Conservation
Phone: 707.778.4507
Email: conservation@ci.petaluma.ca.us

Report Water Waste

Field Office
202 N. McDowell
Petaluma, CA 94954
Phone: 707.776.3777