Las Vegas Wash restoration site. OHV is just another term for ORV - Off Road Vehicle. Given the dense human population in the area there are many quad and motorbike enthusiasts. Even though they tear up the desert around the Wash, most of the restoration sites do seem to get left alone.
Las Vegas Wash
As can be seen in the photo over at the right, the Las Vegas Wash is a narrow band of green running through an arid environment. It is an unusual community made up of wetland and riparian plants growing in the middle of the desert. What really makes it unique however is that it did not exist (at least not in this form) a hundred years ago.
Historically, even though it is the single outlet draining the entire Las Vegas Valley (see map below right), the Wash flowed only intermittently, mostly following rainstorms. Now it carries a significant continuous flow , made up of treated wastewater, and runoff from landscaping.
Additionally, stormflows have increased dramatically as a consequence of urbanization. Roads, parking lots, and the roofs of buildings, are impermeable, catch rain, and concentrate it as runoff. The satellite images below show just how much urbanization has occurred in the Valley in the recent past. Developed areas in the desert show up as green due to the influence of water from human activities: irrigation, landscaping, and wastewater flows.
Satellite images released by UNEP in 2005, showing urbanization in the Las Vegas Valley between 1973 and 2000. A white arrow has been added to the lower right corner of each to indicate the location of the Las Vegas Wash.
Continued: The Wash today
Las Vegas Wash in LVWCC Photo
Map showing location of the Las Vegas Wash