This visualization allows you to explore patterns of per capita water use among urban areas in California. I was inspired by Jan Tulp's amazing visualization Close Votes, leading me to shamelessly replicate his project using data collected by the Department of Water Resources (DWR) under the Urban Water Management Planning (UWMP) Act. The Act requires the collection of various indicators, including water transfers, use by various sectors (e.g. single- vs. multi-family homes, industry, agriculture), and per capita water usage.
Most of this was never before publicly available and it serves to help achieve California's goal of reducing per capita water consumption by 20 percent by the year 2020, mandated by legislation passed in November 2009 through SB X7-7 (Steinberg). As with a lot of the water-related paperwork required in California, there's loads of interesting data in the volumes of reports prepared by over 350 cities and water districts subject to the reductions, but its really hard to understand in a comprehensive manner.
To help me digest the data, I requested all the data DWR had from these reports. I"m not sure if anyone had made such a request so it took a little while to get everything, but eventually a treasure trove of data was provided in spreadsheet format. I've made everything DWR provided available here.
Jan Tulp's idea to transition between geographic and radial display of voting data, and also permit sorting by population size and similarity in voting patterns, seems to also lend itself to comparing water consumption patterns.
The links at the top left of the screen allow you to toggle between population size and similarity, as well as geographic vs. radial display. When in population mode, the size of the circle indicates how many people are served by the city or water district and the coloration indicates the cities have a similar per capita water consumption. When in similarity mode, both the size and color of the circle relates to similarities in per capita water consumption.
The radial display takes geography out of the mix and just relates the urban areas by consumption. You can toggle back and forth to find some interesting patterns. Coastal areas generally have lower consumption patterns (e.g <150 gallons/per person/day), probably related to climate and property values (small lot sizes and fewer lawns...?). The Central Valley and Inland Empire areas have larger consumption patterns, while the highest per capita consumption is in agricultural areas, including Rainbow and Valley Center, in north San Diego County, where I assume a lot of avocado growers are using potable water. Is that why I'm paying $3 for an avocado these days?
To help compare cities I also provided a little 'Thirst Meter', which indicates where a city ranks among all others. Hover over a city to see the ticks move across the bar chart. Cities at the center of the spectrum use about an average amount, which is 198 gallons/person/day, based on baseline data collected over 5 to 10 year periods prior to 2010, depending on the city.
It's important to note that this data is an aggregate of all municipal uses on a per capita basis, including domestic, industrial, and agricultural use. Cities with large industrial areas or a number of small farms will be skewed against dense coastal cities with a large residential population and few industries or irrigation requirements (e.g. San Francisco).
The live visualization is best viewed on Chrome, though most modern browsers should work fine.