The Sun Valley Park (Los Angeles, CA 91352) 
Stormwater to Groundwater system

The Sun Valley Park stormwater to groundwater system is a wonderful idea. There are some problems with implementation that is keeping this system from living up to its claims.

The Sun Valley Park Stormwater System as designed!

It has been claimed that an automatic oil-spill shut-off valve is too sensitive and has been shutting off the system. If this is the case, then the valve fails in two respects. First, it shuts off when there is no spill. Secondly, it doesn't shut off completely. By watching storm events over the last two years, as the storm passes, the water in the catch basins drains into the system without anyone coming by to reset the valve. So if the valve had shut automatically, it does not fully protect the system since the flow continues into the system.

The main obvious problem (from surface observations) is that the majority of the catch basins have been screened in fully without any high flow bypass. These screens get clogged as shown below resulting in very little flow into the system. 

A proposed modification to the catch basin screens is proposed at the bottom of this page that can allow high flows with minimal garbage passage. 

                             

These cages in the catch basins are not the standard design. The standard design  has a storm overflow that allows high levels of water pass the screen. The project manager installing the system, had the manufacturer of these catch basin screen cover over the storm by-pass. The intention was to prevent any garbage from entering the main treatment system. The main treatment system is designed to remove the garbage, however, then the main treatment system would require more maintenance pumping on the hydroseparator. 

The above video was taken about 10 minutes after the below video.
The below video is at the beginning of a storm and accepts all the water.
The above video, the storm flow has grown and now by-passes the drain.		 The above photo is the storm drain on Fair Ave just north of Cantara St. The metal grate is completely covered with plastic bags and dirt

                   

This is the drain on Cantara Street that the main flow passes over. The size of the filter holes are evident compared to the leaves. This removes the need for the more expensive filter in the treatment system. The water is standing water during no storm or drainage showing that there still is some blockage in the pipes or treatment system.

 

This video is showing one of the drains on Fair Ave just north of Cantara St.
This stops accepting water rather quickly.

 Another drain in the system showing how the filter screen clogs up.
Here is a proposed idea for a catch basin screen that will not clog. It has a high flow bypass. However, it will minimize the passage of floating garbage. This occurs since by the time the water level is higher than an inner screen, it is under a screen coming from the top. Most floating garbage will be held by this upper screen but water will be able to flow freely without passing through a potentially clogged screen.

This image is of the standard manufacturer design of the catchbasin screens. Notice how the top of the screen opens up to allow high water flows. This image is from the manufactures website. The catchbasins in the Sun Valley Park System do not use this design.