California Regional Hydrological Map

Our series of regional hydrological maps show the Water Resource Regions of the USA which is the first level of classification used by the USGS. Its purpose is to divide the US into smaller hydrologic units which are then subdivided. The 21 major Water Resource Regions contain the drainage area of either a major river or the combined drainage areas of a series of rivers. Water is literally the lifeblood of our country. If you’re drawn to water, you know that how and where it flows tells the story of a place. The California Water Resource Region contains the drainages into the Pacific Ocean from within California as well as the drainages from the Great Basin that discharge into California. This map shows in fascinating detail how the rivers and streams flow and interconnect, merge and diverge, carrying life to the land. The flow of water also has an inherent aesthetic elegance that our map captures beautifully. It’s all in the details. Our map depicts every river in the Water Resource