Not since its inception in the late 1930s has Lake Mead been so sparsely filled. The water only rises to 30% of the capacity of this gigantic reservoir of the Hoover Dam, straddling Nevada and Arizona, a level so low that a pump is now in the open air. The lake, fed by the Colorado River, is suffering the brunt of the drying up of this source, the flow of which has dropped by 20% in a century, according to a recent American study. This should still continue, the American West suffering for more than twenty years a historic drought aggravated by global warming. The situation is worrying for millions of Americans and Mexicans, depending on Colorado for their drinking water. But it was also expected: the river has been overexploited for decades.
So, in an attempt to limit a future disaster, the authorities are looking to reduce Americans’ water consumption and have found a prime target: the lawn. In the United States, the lawn is considered by NASA to be the largest “culture” irrigated, ahead of corn and wheat. Symbols of a flourishing America, grass beds surround houses and buildings even in fairly arid localities, such as California or Nevada. To keep it green and attractive, this lawn must be watered almost continuously, an annual water expenditure that can amount to hundreds of liters of water per square meter.
Patrols and fines
“It’s okay to have your lawn yellow,” assures Adel Hagekhalil, manager of the water distribution cooperative in Southern California. In his region, the watering of the lawn has just been limited to once a week for 6 million inhabitants. A rule sometimes badly accepted, the public water agencies having received many complaints from Californians. In some districts, patrols have even been created to detect violations of the regulations. As a result, a fine for recalcitrants and in the event of a repeat offence, a water flow limiter can be installed.
In southern Nevada, which is home to Las Vegas in particular, the authorities have decided to go even further. Passed last year, a law aims to ban all lawns by 2027 “non-functional”, that is to say, useless in the eyes of the legislators. Are targeted, the squares of grass “where no one walks except to mow them”, especially along sidewalks and around buildings. The aim is to remove these pieces of grass, which would cover more than 1,500 hectares in the region, saving more than 35 billion liters of water annually. A resource that is all the more crucial as it is also used to produce a large part of the electricity.
The lawn “outlaw” is replaced by gravel, artificial grass, or more drought-tolerant plants. Although they are not directly affected by the measure, individuals are also getting involved. Since 1999, they have been financially incentivized to give up part of their lawn. But the cost of this kind of work exceeds the help offered by the authorities, and the results have not been enough to slow down the region’s water consumption. The measure, however, is emulated elsewhere, such as in Utah.