Covering 27,000 square miles from the Oregon border to the Delta, the Sacramento River Watershed includes most of northern California and is linked to every aspect of life in the region. As one of the largest watersheds in the United States, it is the lifeblood for hundreds of wildlife species, serves as an important source of drinking water and as a vital economic artery for commerce and agriculture. The watershed contains the headwaters that supply over 30% of the state’s total runoff, contributing significantly to a complex water management and transfer system.
The State of California’s water supply infrastructure supports a $47 billion agriculture industry (2015 CDFA) and provides drinking water to 25 million of residents is a complex system of dammed reservoirs, canals, conduits, and pumps stretching from Lake Shasta in the north to the hills of the Santa Ana mountains in the south. To help region stakeholders understand the scope and scale of the California’s water supply infrastructure system, and the role of the Sacramento River watershed in the system, 34 North developed a comprehensive and interactive map based data story.
While many pdf and jpeg maps exist to describe this system that includes both the State Water Project and Central Valley Project, none were found in the format of GIS shapefiles that could be combined with other layers for more detailed analyses and visualizations. To address this issue, 34 North scientists compiled a list of the key features of both the State Water Project and Central Valley Project and assessed which features would need to be created or combined from other existing data sets.
Using QGIS open-source software, 34 North merged, modified, and created GIS shapefiles to visualize the statewide features of California’s water supply infrastructure. Rather than just show the location of reservoirs, 34 North displayed the size of reservoir points based on the storage capacity of the reservoir. This analysis and styling technique reveals an additional layer of information related to water supply and reservoirs in the state of California, visualizing the significant amounts of water that are stored in the northern part of the state to supply water to areas further south. The final product of GIS data resulted in a shapefile created for each of the State Water Project and Central Valley Projects’ reservoirs and canals, and a third shapefile of features that are part of both projects.
These layers are now available for map making and download on the Sacramento River Watershed Portal and can be seen in the image below.