There are several types of drains used in the City of Palm Springs to deal with surface water run off. The first is a catch basin / storm drain. This type of drain collects water from both nuisance water from sources such as sprinklers and larger volumes of water from rainstorms. These drains collect the water and transport it into the storm drain system which dumps into the flood control channels. The water then percolates into the soil.
The second type of drain called a down and under drain, shown in figure one, has an inlet drain on the uphill side of the intersection or driveway. The drain collects water and feeds it into a pipe that runs under the driveway or intersection where another grate allows the water to “bubble up” through hydraulic pressure and outlets it onto the street surface where it runs down the street. These down and under drains are interim methods of dealing with daily water problems that cause hazards for traffic when the water runs across the intersection.
There is still $50 million worth of storm drain not constructed in this City and although the storm drains are being constructed gradually, there isn’t any way that all of it could be put in to eliminate these temporary “down and under” drains. Water run off from properties will always collect in the drain system, as the hydraulic pressure from the other water is the only way to force the drainage out of the outlet structure and down the street. Since the recent West Nile Virus out break City staff is more diligent than ever when it comes to watching these structures. The most common complaint the City gets regarding these systems is that there is standing water in the pipes and that there is a fear that mosquitoes will hatch in the water and spread the West Nile virus.
Since the vast majority of these systems are in place to deal with daily nuisance water the turn over of water that is trapped in the pipes is very short. Usually the water in the pipe is turned over daily.