How much water is too much water? | A New Shade of Green | Sherry Listgarten

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A new shade of green

By Sherry Listgarten

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About this blog: Climate change, despite its enormous impact on the planet, is still an abstract concept for many of us. That needs to change. I hope readers of this blog will gain a better understanding of how our climate is evolving… (More) About this blog: Despite its tremendous impact on the planet, climate change is still an abstract concept for many of us. That needs to change. I hope that readers of this blog will gain a better understanding of how our climate is evolving and how they would like to respond, and feel comfortable asking questions and sharing comments on the subject. It is important that we develop a common understanding of basic science and the impacts of climate change in order to understand our actions and policy options for the future. My background isn’t in climate science, and I’m not even particularly green; I hope this helps make this blog more accessible. I studied math and neurobiology on the east coast before moving here in 1987 to study computer science. After working in the technology industry for about 25 years, I retired a few years ago to better focus my time on my priorities. I love spending time outdoors and I am deeply committed to our responsibility to this incredible planet we call home. (Hide)

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Uploaded: June 19, 2022

We’re in our third year of drought in California and it’s not pretty. SoCal residents are subject to some unusually strict restrictions. Our area has softer boundaries, but this can get tougher as the summer progresses. Many of us are trying to use less water, but it’s getting harder and harder and it would be nice to know when you’ve done enough. Hence the title of this blog post: How much water is too much water?

Unfortunately, I don’t have many more answers than you do. If you have a lush green lawn and your watering is making puddles in the street, you are probably using too much.

And probably if your yard looks like this or you don’t have a yard, you’re doing pretty well.

But there are many meters that lie in between. All of the yards shown below look great and appear to have fairly drought tolerant plantings. Residents may wonder, are they saving enough?

How do we know when we’ve done enough? I have no idea. But I thought I’d share how much water my house uses and maybe you’ll share yours and we can get a common idea of ​​where we are.

My house uses a boatload of water, despite our efforts to use less over the past three years. Here is a chart showing our monthly water consumption.

Monthly water consumption in my home from January 2017 to May 2022

You can see that our water consumption is used almost exclusively for irrigation, which is turned down during the winter months. (1) In 2019 our gardener switched all watering to once a week. You can see that we used less in the hot summer months but more in the other months because there was little rain. (Graph peaks are shorter but wider.) Look at how much water we used in January and February 2021 compared to previous years. It’s ironic that when you have a drought, you end up using more water.

Last summer, our gardener reduced watering even more by switching several zones to water only once every ten days (2) and further reducing watering times. I knew we would lose the thirstier plants, but that was okay. It was a kind of survival-of-the-fittest competition. The backyard lawn was getting worse and worse, and in September we mulched it.

We mulched the lawn last fall.

I’m not sure what our water usage will be this summer, but I think we’ve made a decent dent compared to 2019 and even 2020-21.

But is it enough? We still use an enormous amount of water. If we use 10 CCF(3) in a summer month, which is a lot of savings, that’s still about 250 gallons a day. With only two people in the house, that comes out to 125 gallons per person per day. The map in this article shows that the per capita water use in 2020 was 40 gallons per person per day in East Palo Alto, 64 in Mountain View, 71 in Menlo Park, and 101 in Pleasanton. Ooh, hey, it’s 125 in Los Altos. I’m not alone! (To be fair, the average month in our home is probably below 10 CCF.)

Last summer I measured our water consumption every day for a few months.

Watering days dominate, using over 750 gallons (100 cubic feet) of water. The other days we use between 4 and 10 cubic feet, which equals 30 to 75 gallons. Even that struck me as a lot. When we didn’t have showers or laundry or dishwashers, we still used 30 gallons. On what? But the gauge doesn’t show a leak, and given the scope of our irrigation job, I didn’t bother to investigate.

If asked, could we use less without killing even more plants? I’m not sure. The lot is large — 9200 sf — and the house and driveway take up only 2500 sf, leaving plenty of greenery that needs water. There is a large pepper tree in the front, an even larger elm in the back, plus all manner of hedges, smaller trees and shrubs galore. These are established plants that are not very water hungry, but they still need water. Front watering runs every ten days, one zone at 15 minutes, another at 10 and one drip zone at 45. Rear watering runs weekly, with five zones at 15 minutes and one drip at 30. It’s about 2.5 hours each week, and will likely be more as the days get hotter. (4)

Just some of the plants I water.

Also, at some point I want to replant the freshly mulched area in my garden, which means even more water consumption, especially when the plants are young. I will try to select drought tolerant natives but still.

Where is all this leading? I don’t think Palo Alto will send out the plant police, but I’m wondering how that’s going to be handled. If the drought persists, how should we develop our farms? I do not know.

Would anyone else like to share how much water you use, where you saved water, where do you think most water goes now, and if there is one place you can’t imagine saving?

Notes and references
1. Some watering is still done in winter because under the extended roof line.

2. Before that I didn’t even know that you can water every ten days. The corresponding setting on my Rainbird watering box is called “Skip days”.

3. 1 CCF = 100 cubic feet = 748 gallons.

4. I don’t know what types of spray heads are used for irrigation or, more generally, how much water each zone uses per minute.

Current climate data (May 2022)
Global Impact, US Impact, Carbon Metric, Climate Dashboard

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