It’s the winter rainy season in California again, so time to check on the status of the water in the California reservoirs. I previously made a “bar graph” showing the overall level of water in the major California reservoirs. This dashboard provides a bit more detail on the state of each of the reservoirs while also showing an aggregate total. It updates hourly using data from the California Department of Water Resources (DWR) website, giving an up-to-date picture of California reservoir levels.
This is a marimekko (or mekko) graph which may take some time to understand if you aren’t used to seeing them. Each “row” represents one reservoir, with bars showing how much of the reservoir is filled (blue) and unfilled (brown). The height of the “row” indicates how much water the reservoir could hold. Shasta is the reservoir with the largest capacity and so it is the tallest row. The proportion of blue to brown will show how full it is, while the red line shows the historical level that reservoir is typically at for this date of the water year. There are many very small reservoirs (relative to Shasta) so the bars will be very thin to the point where they are barely a sliver or may not even show up.
If you are on a computer, you can hover your cursor over a reservoir and the dashboard at the top will provide information about that individual reservoir. If you are on a mobile device you can tap the reservoir to get that same info. It’s not possible to see or really interact with the tiniest slivers. The main goal of this visualization is to provide a quick overview of the status of the main reservoirs in the state and how they compare to historical levels.
You can sort the mekko graph by size – largest at the top to smallest at the bottom – or by reservoir location, from north to south.
Units are in kaf, thousands of acre feet. 1 kaf is the amount of water that would cover 1 acre in one thousand feet of water (or 1000 acres in water in 1 foot of water). It is also the amount of water in a cube that is 352 feet per side (about the length of a football field). Shasta is very large and could hold about 3.5 cubic kilometers of water at full (but not flood) capacity.
Data and Tools
In my previous post, about California water levels, I presented a “bar graph” showing the amount of water currently in California’s reservoirs. However, I thought it’d be interesting to see how this has changed over the course of the last few months, since the state has gotten alot of rain and snow recently. I decided to try and “animate” the graph for the current water year (going back to October 1, 2015) showing how the recent El Nino rain has been filling up the reservoirs in California. Click the “animate” button below the figure and you can use the slider to change the speed of animation as it cycles through the days. (more…)
California has had an issue with drought, especially for the past few years now. Recently, 2016-2017’s El Nino weather patterns has brought a significant amount of rain to the state and helped alleviate some, but not all, of the major issues.
I’ve been very curious to understand how the rain storms we experience are lessening the impact of the drought, and whether one wet season (like 2016-2017) can really “get the state out of a drought”. One way to assess this is to look at the status of California reservoirs.