Data source: California Department of Water Resources
California’s landscape is peppered with a huge collection of dams and reservoirs, providing water — and in some cases power — to cities and farms throughout the state.
Most of these reservoirs typically fill up during the wet winter months and are slowly depleted over the course of the summer and fall (with some exceptions for reservoirs mainly used for agriculture and power generation that follow scattered release schedules). But these aren’t typical times for California: following several below-normal years of snowfall and rain, 2013 clocked in as the state’s driest year on record. And although last month’s storms helped soften the blow, in the grand scheme, they were — ahem — just a drop in the bucket.
The visualization above, created by Bay Area web developer Victor Powell, shows fluctuations since 2010 in California’s 30-largest reservoirs. As of mid-March, many are at strikingly low storage levels (although some are much fuller than they were just a month ago), leaving water agencies throughout the state scrambling for options as a long, dry summer approaches.
The grey border marks each reservoir’s maximum capacity, while the blue shows fluctuating storage levels over time. All reservoirs are scaled relative to each others maximum storage capacity by area (with the largest — Shasta Lake — at 30 pixels). Click on each reservoir to graphically see its change in capacity over the designated time period. You can also view these changing percentages by mousing over the reservoir pop-out to the left of the graph. Use the slider at top to select specific times.
Source code and data is open source and available here.
Resources for finding out where your water comes from (in California)
- KQED’s map of Bay Area water districts by major source of supply
- NRDC’s water district finder interactive
- Water Education Foundation’s regional water tracker
Victor Powell is a Berkeley-based web developer, specializing in data visualization. He runs the consultancy Setosa.Related