Tahoe Resource Conservation District

Tahoma Monitoring Site

cmoore_151021 (9)

Site Photo


Site Hydrographs

Tahoma Catchment Map 1

Catchment Map


Catchment Size:

49.5 acres

Dominant Land Use:

This catchment is located in medium density single-family residential neighborhoods crisscrossed with secondary roads, and also includes some commercial/industrial/communications/ utilities and primary roads.

Percentage of Impervious Surface:

28% of the catchment area is impervious


Placer County, El Dorado County, and Caltrans


The Tahoma catchment straddles the Placer County/El Dorado County border and is transected by Caltrans maintained Highway 89. The runoff from this catchment discharges directly into Lake Tahoe via a 36-inch oval pipe at the bottom of the Water’s Edge North condominium complex driveway without infiltration or treatment; the monitoring station is located at the outfall of this pipe. Because of the high direct connectivity between the catchment and Lake Tahoe, this storm drain system has great potential to deliver high fine sediment particle (FSP) loads to the lake. No recent water quality improvement projects have been completed in this drainage. However, due to steep roadways, road sand and cinder accumulation, eroding cut slopes, drainages, and roadside ditches, as well as direct discharges of untreated stormwater to Lake Tahoe, the TRPA has identified the area as one that requires erosion control and water quality treatment BMPs.

An environmental improvement project, slated to begin the summer of 2017, will focus on reducing the delivery of FSP to the lake through source control, hydrologic design, and stormwater treatment. Source control will be achieved by stabilizing eroding slopes with vegetation and/or rock armoring, stabilizing existing drainages with rock, and eliminating eroding roadside ditches by installing curb and gutter or rock-lined channels and vegetated swales. Improved hydrologic design will store and spread out stormwater more effectively in the upper watershed and infiltrate and/or treat runoff from the El Dorado County and Caltrans right-of-ways before it discharges to Lake Tahoe. El Dorado has also proposed working with Caltrans, the California Tahoe Conservancy (CTC), Placer County, and private land owners to develop a comprehensive watershed management plan within the project boundary. The Tahoe RCD anticipates seeing reduced runoff volumes and pollutant loads discharged to Lake Tahoe following the completion of this project.