3 – People and droughts

Hi everyone!

In our last article, published in Montana, we were speaking about the use of freshwater for agriculture and cattle farming in areas with low population. Since then, we have continued our trip driving through Wyoming, Idaho, Utah, Nevada, California and Arizona, and getting every day closer to much dryer regions. Today, drought will be the topic of our article. How is freshwater distributed when it has to provide for a lot of people (California has 92 habitants per square kilometer when Montana had 2,6) and when overall rainfall decreases every year…?

How do you provide LA, a 17 million people city ?
How do you provide LA, a 17 million people city ?

Just after we pass the Idaho border, we enter the “Great Basin” of the US. This is the name given to a region that covers the South West of the US from West of Utah to South California and down to the Sonora desert through the Mexican border. The area is marked by its very arid climate, and by the fact that overall precipitations are very low. Especially the state of Nevada suffers from this hydrology: it is the driest state of the US with only 104mm of rainfall per year. However Nevada consumes a lot of water to maintain its economy, especially for entertainment and tourism which greatest symbol is the city of Las Vegas! Nevada consumes also a lot of water for the extraction of gold in its mines (Nevada is the fourth producer of gold worldwide).  All of this makes the hydrological situation of the region worse and worse every year and there is a point when resources of freshwater might come to an end…

 

A two hours drive from Las Vegas and it is Death Valley desert
A two hours drive from Las Vegas and it is Death Valley desert
The famous fountain show from the Bellagio, in the middle of a dry desert !
The famous fountain show from the Bellagio, in the middle of a dry desert !

In order to provide water for the area, the most common technique is to build huge water dams and to create artificial lakes. With Grégoire, we had the opportunity to pass by two of the most famous ones: Lake Powell and Lake Mead, the last of which retains the water from the Colorado river before it is divided between the different states of the region. When driving by the mountains of the Sierra Nevada, we noticed a lot of those artificial lakes on the sides of the hills and when we reached the city of Sacramento we drove just by the Folsom Lake that provides water for the entire town. Anyway, for all those lakes the water levels are reaching critical points! We can feel the drought is striking the region just from our car with a lot of big road signs on the side of the road to raise awareness about the importance of water in the region. On the other hand we also notice that all the lawns we are passing by are very green, a lot of people have a swimming pool in the back of their garden and a lot of golf courses punctuate the road… Add to that the importance of water for maintaining the local agriculture (farming in the Sierra Nevada, orchards of Salinas, vineyards of the Napa Valley) and you can understand the very tense situation between the different states of the region…

 

Lake Mead is one of the biggest american freshwater reserve, but around 20 to 30% of the water evaporates
Lake Mead is one of the biggest american freshwater reserve, but around 20 to 30% of the water evaporates
Glen Canyon Dam holds back waters from Lake Powell
Glen Canyon Dam holds back waters from Lake Powell

To get a better insight of the situation, we meet Chloe Fandel, who is currently preparing a PhD in hydrology at the University of Arizona (UA) in Tucson. For a couple of years, Chloe has been working on the issue of retaining water and facilitating its infiltration into the ground. Her research project tends to find alternative solutions to the huge dams and artificial lakes I mentioned earlier. Indeed Chloe explains to us that those dams are not a sustainable way to deal with water. The main problem is about evaporation. During summer, up to 30% of the resource can be lost because of evaporation! But it also affects the quality of water, making it too much salty than what it is supposed to be. It is especially true for the water that supplies the cities of Tucson and Phoenix in Arizona. This water comes from the Lake Mead through a canal called Central Arizona Project (CAP) and that runs for 300 miles (500kms) through the desert! When it reaches the cities, the water is often not pure enough for a healthy consumption. Moreover, the Lake Mead’s level is decreasing every year because the legal amount of water the states can take from the lake does not include variable considerations as overall rainfall of the year. As a result, the amount taken is superior than the amount of water that comes to the Lake and today the water level is getting close to the level of the pipes…

The CAP ditch runs through 300 miles in order to provide water to Tucson & Phoenix
The CAP ditch runs through 300 miles in order to provide water to Tucson & Phoenix
A waterpump of the CAP, very demanding in energy
A waterpump of the CAP, very demanding in energy

Chloe tells us that the local jurisdiction is very complicated and prevents from decisive action at a federal level. As a result, the situation remains unchanged and some hydrologists are predicting the extinction of the Lake Mead resources by 2025. However Chloe also tells us about some local initiatives and about people being aware of the situation. Now, people are getting used to grow cactuses in their backyards, sometimes better than green lawns. The city of Tucson restricts the use of used waters for watering the golf courses too ! Chloe takes us on a drive to see the canal that runs in the middle of the desert and she also takes us to a giant copper mine that surrounds the city of Tucson. This mine consumes a lot of water and she reminds us that small initiatives are for everyone and contributes to dealing with the problem. For instance you may have not thought that renewing your smartphone less often would contribute to lower the water consumption (indeed a lot of water is needed to extract all the elements in your phone), or reducing your consumption of meat, of cotton shirts, etc. Choices are simple and their importance should not be underestimated.

A board that encourages people to beware of local water issues
A board that encourages people to beware of local water issues

The subject of her research is directly pointed toward a smarter use of the resource. Chloe says that once every year, Arizona finds itself in the middle of heavy rains that usually create dangerous and devastating flows as the soil is too dry to retain the water. This period usually comes with the apparition of “ephemeral rivers” that are dry most of the time but full of water for a few days every year. For Chloe the objective is to determine whether it would be useful or not to build a lot of small dams called gabions on the side of those rivers in order to slow them down and allow water to infiltrate the soil. We wish her good luck and we will pay a lot of interest in the conclusions of her study!

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A « gabion », the kind of structure Chloé is currently working on

We also had the opportunity to see a similar intiative during our stay in California. In San Diego we met Chiara Dorigo who works for a start-up called Greyble that plans to reduce the consumption of water in the region by reusing the water from any house to water the garden. The device she has created can be associated to any house and will automatically collect used water and turning it into appropriate water for the plants. It is also entirely connected to your smartphone so you can control your water consumption in your household. In the long term Chiara claims that this device can save up to 20-30% of water per house.

The Greyble prototype, that reuses spoiled waters for domestic irrigation
The Greyble prototype, that reuses spoiled waters for domestic irrigation

As a conclusion, we noticed in person that the drought was affecting deeply the people in the South West of the US. Luckily, the US is a developped country and has financial resources for dealing with the resource. Dams, ditches, artificial lakes… those may not always be the best options but they are still good ways for providing water to the people. What happens in regions where the State cannot support such initiatives?

Next month we will be in Mexico and we will talk about the management of freshwater in a developing country. The subject is crucial and very related to the US issues as the Colorado river, just after passing by Phoenix and Tucson continues down to the Mexican border with a greatly reduced flow…

The Colorado river, when leaving Lake Powell
The Colorado river, when leaving Lake Powell

You’ll find here a video summing up our month there, and an interview with Chloé Fandel, who generously accepted to show us around, and answer our question 🙂 Thanks a lot !!

See you soon !

Greg & Antoine