To collect rainwater from the area we decided to use the already existing collection system: a relatively well-established wash. Paul Measeles, a hydrologist, helped us design a device to catch the rare rains. We built a gabion (Structure made of piles of stone enclosed in wire, mostly used to fight erosion. In our case it is used to catch and pre-filter the water from the wash.), installed a French drain (pipe with holes) right downstream from it and from there, giving it a 1% slope, we attached pipes that served Garden #1 directly and Garden #2 through a silt trap, a 200 gallons water tank and a battery-operated watering timer.
With these conditions, the tank has not received
an inch of water this year but we got an unexpected result, confirmed
by the data logger: this garden #2, being a few feet below the surrounding
surface, is much more humid than the others. Is it because the slopes
and the berms protect it from the dessicating winds? Or is it because
it is below the level of the wash?
Water Catchment System
Slideshow showing time-lapse construction of the system (760KB - Quicktime 6 required)
Scientists use tree-ring reconstructions of
Colorado River flows to estimate what conditions were like before
recordkeeping began in 1895. Using that method, the lowest five-year
average of water flow was 8.84 million acre-feet in the years 1590-1594.
From 1999 through last year, water flow has been 7.11 million acre-feet.
‘These comparisons suggest that the current drought may be comparable
to or more severe than the largest-known drought in 500 years,’
the report said.
NOTES ON RAINFALL IN THE MOJAVE DESERT
The Mojave Desert lies in the rain-shadow of the Coast Ranges and receives an average annual precipitation of 5 inches. Most of the rain falls between November and April. There is, however, a summer thunderstorm season from July to September with violent and heavy rainstorms possible. In 1986 only 1.5 inches of rain fell on the Eastern Mojave Desert, while in 1983 the region saw 6.5 inches. May and June are usually the driest months.
Recent trends in Mojave Desert precipitation suggest that the climate of the region may become drier over the next 2 to 3 decades. These limited rainfall patterns are similar to those that occurred during the very dry mid-century conditions.
Although there are many uncertainties and assumptions, it is important to consider the potential affects of climate variation on the human and natural resources of the region. Water resources were heavily affected during the early part of the 1942–1977 dry conditions, and the population of the region has increased tremendously since the mid-1950s. The increasing demands for water in the Mojave region and the creation of severe or catastrophic consequences are probable if such a drought continues.