The Hydrology of California

The Hydrology of California

Stephanie Trump
May 2008

ES 551 Computer Mapping Systems

From this map of California, one can see the hydrologic features. Rivers are in blue and lakes are in red. Many of the surface water bodies are concentrated in the Central Valley and northern part of California, while the southern third of the state is rather lacking in surface water. The southern third of California is, in fact, rather dry, and a desert in most locations. Some notable surface features are the San Fransisco Bay, located on the western side of California, about in the middle, Lake Tahoe, on the eastern border, where California "bends", and the Salton Sea, the large water body near California's southern border.

The data were downloaded from the California Spatial Information Library's website. According to the website, the datasets of hydrologic features are digitized from 1:24,000-scale USGS topographic maps. There are two datasets, hydro_linear and hydro_poly. The hydo_linear file contains information regarding linear features, such as rivers, and the hydro_poly dataset shows polygonal surface features, such as lakes. These files were intended for use with the software, ESRI, but were converted to vector files and the map was created using IDRISI Andes. The two datasets were overlain, and a dataset of the political boundaries was added as a recognizeable reference. The image was then converted into a bitmap file.