Land and Water Use
- Land & Water Use Data Collections
- Annual Land & Water Use Estimates
- Agricultural Water Use Models
- Statewide Irrigation Methods Survey
- Study Area Maps
DWR Related Links
Water Use and Efficiency
901 P Street
P.O. Box 942836
Sacramento, CA 94236
- Land Use Survey Overview - The main emphasis of DWR's land use surveys is the mapping of agricultural land. Over 70 different crops or crop categories are included in our surveys. Irrigation methods and water sources have also been mapped in some, but not all surveys. Urban and native vegetation (undeveloped) areas are mapped but not in the detail of agricultural land.
These land use surveys were performed using aerial photos and, more recently, satellite imagery to define field boundaries. For earlier surveys, DWR staff used U.S.G.S. 7.5' quadrangle maps as base maps for delineating field boundaries and recording land uses. As large format printing of aerial photographs became available, plotted aerial photos were used as field sheets for recording land use attributes. Currently, most of the land use survey data is entered directly into a digital map using geographic information system (GIS) software on a laptop computer. Georeferenced, orthorectified imagery is used as a backdrop, and the land use boundaries are visible on top of the imagery. Department staff visit and visually identify land uses on over 95 percent of the developed agricultural areas within each survey area. A GPS unit is incorporated with the computer, so the user can see their current location on-screen.
After the field work has been completed and the maps have been checked for errors, a digital composite map of the survey area is created from the work of individual surveyors. Using GIS software, digital maps of quads, counties, water districts, and the DWR's hydrologic planning units (Detailed Analysis Units) can be overlaid on the land use data to develop acreage summaries of land use by these areas.
Every digital survey has a metadata file which explains more specifically and in more detail how that survey was performed.
- Land Use Data -
Following is a list (by year) of the land use survey data that are available from this site. The shapefile of the land use survey data, the metadata, the land use legend, and an explanation of the land use attributes in the shapefile have been combined into a single zipped file for each survey. Click on the survey area and select "Save" to download the data to your computer.