I keep hearing that California is experiencing terrible droughts and there is a huge concern over the amount of water we receive. I can tell that there is less rain up here in Humboldt than there used to be, but I also feel we are in a pretty good spot to weather water shortages considering we live in a rainy coastal area. Do the droughts really affect us and should they be influencing how we use water up here?
-Curious Water Consumer
Dear Curious Water Consumer,
In general, you are right. Humboldt is a very rainy place, and has a small population. But, the climate is changing. California’s January, February and March were the driest since we began taking records, at least 150 years. If you are concerned about our water supply, you would do better to stop driving your car than limit your showers. Let me explain:
Northwest California has received 6 inches of rain in the last few weeks. So, we’re currently not really in a time of water shortage. In Eureka, McKinleyville and Arcata, water is drawn from the Mad River. There’s currently 1000 cubic feet per second of water flowing through the Mad River and out into the ocean. However, just last month, on March 31, after three months of no rain, the river had gotten down to 157 cubic feet per second. This is only about 10% of the average flows that we’d expect for this time of year. I think that statistic really emphasizes just how dry that period was. There are about 7.5 gallons in a cubic foot, so even in that incredibly dry period, the river was bringing us 1,177 gallons per second, or 100,000,000 gallons per day. There are 136,000 people in Humboldt, so that gives us each 735 gallons to use per day. This doesn’t include people drawing water from other rivers in Humboldt, or using well water. So we do have enough water, for now. Unless you are drawing your water straight out of a small creek in the middle of August, your shower isn’t going to make much difference.
But back to the big picture: data from the California-Nevada Climate Applications Program shows that the Sierra Nevada reservoir storage and snowpack combined are now about half the normal levels. Tree rings indicate that the drought affecting the West right now is the driest period in the last 1,200 years. Lake Powell is at its lowest level ever recorded. This is also directly following the 2011 to 2015 drought, which was also considered a once-in-1,000 year event. During that drought, about 150 million trees died in California. The amount of tree death was much less severe where we live in Northern California, and it was really only at the very tail end of the drought, after multiple years without much rain, that we started to see trees die up here.
Does that mean that we are drought-proof? No. It’s very likely that as the climate continues to warm, the West will become drier and drier. This year, at the end of March we had received about 18 inches of rainfall since the beginning of the water year in October. This was 54 percent of normal. The annual average is close to 45 inches. The question becomes, will future precipitation be enough to sustain our Redwood forests? What will happen when we have multiple years with rainfall levels below what trees need to survive?
If we look at other regions of the world that only get around 20 inches of rain a year, we see very different vegetation. This suggests we could lose much of our forests. So that’s an indication of the scope of the changes we could see. It’s really scary. And it’s really sad. Scientists have predicted and warned of these changes. James Hansen, a NASA climate scientist, warned Congress as far back as 1988 of the dangers of human-caused climate change. It’s important to understand that the climate changes for natural reasons, and has done so many times in the past. However, the human-caused climate changes we are now observing are happening 100 times faster than what has occurred in the past. Our natural ecosystems and economies will struggle to keep up with that rate of change. Society needs to face reality and make progress on the immense transformations these facts demand from us. What can we all do to start making a difference? In the big picture, if you are worried about water supplies, fish, trees and everything our ecosystems and economy depends on, being careful with your carbon footprint might be more important than taking shorter showers!
Professor of Hydrology and Watershed Management, Department of Forestry and Wildland Resources, Cal Poly Humboldt