Description: This geographic data provides the general estimated location of the shorezone tolerance district areas. This data is based on plan area maps and older GIS data representing shorezone tolerance districts. This does not accurately reflect the exact location of the shorezone - it merely provides general locational guidance. This data update was completed in 2014.-Definition of shorezone: includes the nearshore, foreshore, and backshore. Nearshore: The zone extending from the low water elevation of Lake Tahoe (6,223.0 feet Lake Tahoe Datum) to a lake bottom elevation of 6,193.0 Feet Lake Tahoe Datum, but in any case, a minimum lateral distance of 350 feet measured from the shoreline. In other lakes, the nearshore extends to a depth of 25 feet below the low water elevation. Foreshore: The zone of a lake level fluctuation that is the area between the high and low water level. (For Lake Tahoe, the elevations are 6,229.1 feet Lake Tahoe Datum and 6,223.0 feet Lake Tahoe Datum, respectively.) Backshore: The land area located between the highwater line of the lake and the upland area of instability or the wave run-up area.-TD1 Description: The beach that forms the shoreline in these districts is a low sandy barrier that separates the lake proper from marshes and wetlands. Generally, the shorezone is ecologically fragile and any substantial use or alteration can lead to excessive sedimentation, beach erosion, and water turbidity.-TD 2 Description: Tolerance District 2 is typically volcanic and morainic debris shorezones with slopes 30 percent and over and alluvial soils at nine to 30 percent slopes. Potential for disturbance in the nearshore is high as is potential for erosion and cliff collapse in the backshore.-TD 3 Description: Tolerance District 3 is armored granite shorezones with slopes exceeding 30 percent. The erosion potential is high immediately above the shore, with moderate potential for disturbance in the steep nearshore zone. Removal of vegetation in the backshore may lead to mass movement and erosion.-TD 4 Description: Tolerance District 4 exhibits volcanic rock shorelines with moderate potential for erosion. The potential increases where colluvium of volcanic debris is present and stoney, sandy loams lie on 15 to 30 percent slopes; on morainic debris shorezones with high erosion potential above the shoreline; and alluvial shorezones where the shoreline is characterized by steep, crumbling cliffs with continuing erosion problems.-TD 5 Description: Tolerance District 5 exhibits armored granite shorezones with 15 to 30 percent slopes with less erosion potential than similar lands in Shorezone Tolerance District 4.-TD 6 Description: Tolerance District 6 is underlain by weathered volcanic or morainic debris with slopes of five to 15 percent.-TD 7 Description: Tolerance District 7 is comparatively level shorezone underlain by morainic and alluvial materials with slopes of zero to nine percent.-TD 8 Description: Tolerance District 8 is gently sloping, armored granite shorezone with high capability for development. Shorelines are in equilibrium and potential for erosion in foreshore and nearshore is low. Backshore possesses a moderate erosion potential in some cases.In addition to the standards set forth in Chapters 84 and 85 of the TRPA Code, the standards set forth in subsection 83.9.2 for Tolerance Districts 4 and 5 shall be applicable to Tolerance Districts 6, 7, and 8. The following standards also shall apply: A. Vehicular access to the shoreline shall not be permitted except where TRPA finds that such access will not cause environmental harm. B. Boat launching facilities and marinas shall be located where the nearshore shelf is of sufficient width to enable construction and use without potential for significant shelf erosion.
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Description: <DIV STYLE="text-align:Left;"><DIV><DIV><P STYLE="margin:0 0 0 0;"><SPAN>The Stream Mouth Protection Zones are locations of streams connecting to Lake Tahoe within a 100-year floodplain. These locations define sensitive watershed areas for focus on Best Management Practices. For the 2008 Shz Update, TRPA mapped the ability of each stream to meander within a given range (100’ to 2,000’). New structures are prohibited in SMPZs. </SPAN></P><P STYLE="margin:0 0 0 0;"><SPAN /><SPAN /></P><P><SPAN /></P></DIV></DIV></DIV>
Description: Three-hundred foot buffer from the Lake Tahoe high water line or mark. The high water line is a contour representing the center of the 1898 and 1899 meter DEM elevation values in the Lake Tahoe Region. This was derived from the 2010 LIDAR (Light Detection and Ranging) data (matches the Tahoe_HE_N.img and Tahoe HE_S.img raster images).H (SIG_Tahoe external hard drive):\Revised LiDAR Data\Rasters\Hydro_Enforced\South\Tahoe_HE_S.img.
Description: USGS/ACoE Original data: http://tahoe.usgs.gov/files/shoalsfaq.htm#quality (the original data are +/- 15 cm). This data was created in July 2000.Six feet was subtracted from the “zero” line at the top of the reservoir (6229.1 ft elevation) to get an approximation of the natural rim. The line is 6223.1ft with +/- 15 cm (or about 5.9 inches) precision.