Tahoe Resource Conservation District

Rubicon Monitoring Site

OLYMPUS DIGITAL CAMERA

Site Photo

Rubicon Catchment Map

Catchment Map

Rubicon-Hydro

Site Hydrographs

 

Catchment Size:

13.8 acres

Dominant Land Use:

This catchment is comprised of low density single-family residential properties with no multifamily residential or commercial properties.

Percentage of Impervious Surface:

24% of the catchment is impervious.

Jurisdiction:

El Dorado County

Description:           

The Rubicon monitoring site was located on Rubicon Drive in the Rubicon Estates subdivision on the west shore of Lake Tahoe. Most of the roadways have unimproved shoulders but a few steeper sections are lined by asphalt dikes. The Rubicon site was monitored as a catchment outfall and a BMP effectiveness project at two monitoring stations. Due to low runoff volumes following the project described below, this site was retired from the monitoring network after water year 2015.

The Rubicon V Erosion Control Project, completed in 2010, installed two sets of parallel Stormtech stormwater retention chambers at the lowest point in the catchment to reduce stormwater runoff volumes to Lake Tahoe through infiltration. The first monitoring station was located at the inflow to the Stormtech chambers and the second was located at the outflow from the Stormtech chambers. Runoff in this area is primarily from Rubicon Drive and flows to a drop inlet where it is conveyed to a 48-inch diameter sediment trap for coarse particle removal before entering the Stormtech chambers. There are two additional sediment traps, one between the two sets of chambers and one at the outflow from the second set of chambers. Each chamber is a 51-inch long, 30-inch diameter half pipe set atop two feet of rock. The first set consists of 24 chambers and the second set consists of 16 chambers. The combined volume capacity of both sets of chambers is 3,000 cubic feet. When all the chambers have filled, the overflow bubbles up through a grate in the roadway and then runs south along the shoulder to a residential property outfitted with several private property BMPs. Also included within the catchment boundary are four “fill and spill” microbasins designed to detain a small portion of the runoff before entering the Stormtech chambers and a small perforated pipe infiltration gallery. The microbasins consist of shallow depressions in the ground with a sediment trap at the down-gradient end.

Prior to the environmental improvement project that installed the described infrastructure, high end properties were being flooded by uncontrolled runoff that exited the County right-of-way only 400 feet from the lake. Being so near the lake, this catchment was highly hydrologically connected and had the potential to transfer large amounts of pollutants. The microbasins and Stormtech stormwater retention chambers have successfully captured and infiltrated all runoff in this catchment since their installation.