GGP had experienced some flooding after heavy rains. As a result, the GGPA Board investigated what could be done to alleviate street flooding.
In 2018, then Board Member Cindy Taliaferro contacted Harold Roebuck, County Stormwater Operations Manager II, who met Cindy and GGPA Treasurer Denise Watermeier on GGPA. Mr. Roebuck inspected the storm drains and discussed the issues relating to flooding.
Map of GGP showing Storm Drain Outflows
One88 (188) and Toscano (205) GGP are at the low point of GGP. Storm sewers are at water level, and the increase in impervious area due to new construction on the west side of GGP has increased the outflow requirement. High tides negatively affect the ability to move water into the bay. The City enforces the Codes and is responsible for installation of storm sewers and the county maintains the existing lines.
The County scheduled a cleaning of the three GGP storm sewers with a truck and vacuum line to suck the entire length of the two affected storm sewers, the closest to One 88 and Alta Mer (306) GGP. There was silt accumulation in the 306 GGP outflow at that time.
The outflows also had substantial barnacle growth which limit the amount of outflow at times of high rain. The County removed the barnacles on the outflows during the cleaning in 2018.
Since the outflows have been cleaned, there has been less water during heavy rains. The GGPA will continue to keep an eye on street drainage to consider what steps can need to be taken to reduce the likelihood of the storm drains becoming clogged in the future.
Mr. Roebuck has advised that floating debris will need to be removed in areas near storm sewers. This includes mulch and other materials, such as papers and recycling materials, that will float.
As a result, areas of mulch have been replaced with rocks to avoid mulch clogging up storm drains during heavy rains.
WHAT YOU CAN DO ABOUT OCCASIONAL FLOODING ON GGP
V curbs or V drains are the concrete alleys between the sidewalk and road surface.
These alleys are intended to control and direct the flow of water during rains. When trash and recycle receptacles are placed on top of the V drains, water is diverted into the roadway and it swells and pools creating a pond effect. Water needs velocity and pressure of the continuous force of the flow to push the rainwater into the bay. Obstructing this flow causes the water to collect and swell into the vegetation, causing floating debris, which then plugs the drains as the water slowly recedes.
This means they need to be on the driveway or in the street, off of the drains. If they are smaller bins, they need to be covered.
This is a V-drain - keep trash bins off of it
Water needs to run down this concrete channel- don't block the V-drain!
Make sure that your trash and recycling receptacles do not block the water. Put them on your driveway or outside of the channel so that the water's velocity can push eh water into the drains and bay.
Here the receptacles are outside the V-drain.
Remove as much floating debris from your landscaping
Don't add mulch near the street or where it could float away in high winds or a heavy rain-- use rocks, grass, or ground cover instead where possible.