Climate Resilience Dashboard
EIP Project Tracker
Lake Clarity Tracker
Monitoring Dashboard
Parcel Tracker
Threshold Dashboard
Transportation Tracker
Lands classified as 1b are among the most sensitive in the Tahoe Region and can support the least amount of land disturbance. The percent of land coverage within land capability class 1b indicator measures the percent of land coverage on class 1b lands in the Tahoe Region. The indicator allows up to one percent impervious coverage within land capability class 1b. Land capability class 1b is environmentally sensitive land and includes low-lying stream environment zones (SEZ), stream channels, marshes, floodplains, meadows, and other areas with surface or groundwater. class 1b lands are critical for natural water filtration, storage, and conveyance of surface runoff. Encroachment on these areas reduces their potential to filter sediment and nutrients and the amount of surface runoff they can effectively treat. Naturally functioning SEZs also provide open space, flood flow capacity, riparian vegetation, fish and wildlife habitat, and buffer urban uses in developed areas. Since the adoption of the 1987 Regional Plan, new coverage or even temporary disturbance in class 1b has been prohibited. The updated 2012 Regional Plan carried forward all protection for class 1b (SEZ) lands.
- Status
- Considerably Worse Than Target
- Trend
- Little or No Change
- Confidence
- Moderate
-
The Region is nearing attainment of the stream environment zone (SEZ) restoration target established in 1982 with construction underway for the restoration of more than 500 acres of the Upper Truckee Marsh.
-
The outlook for the Region’s SEZs is significantly brighter today than when the standard was adopted. Development forecasts when the standard was adopted predicted further SEZ loss, between 1,550 and 1,770 additional acres by 1995, without regulation. That did not occur. The USDA Forest Service and the California Tahoe Conservancy acquired and protected over 900 acres of SEZ, and permit conditions and development restrictions prevent any new degradation of non-protected SEZs.
-
To date, projects have restored 1,057 acres of SEZ. Accounting totals historically omitted USDA Forest Service projects completed in the 1980s. When 680 acres of SEZ restoration completed by the Forest Service between 1984 to 1987 is added, partners have restored 1,604 acres of SEZ and restored/acquired nearly 2,500 acres.
-
Despite the 1987 Regional Plan prohibiting all further disturbance of class 1b land, progress toward attainment of the impervious cover standard for class 1b remains challenging. Attainment would require the removal and/or relocation of 659 acres of impervious cover, roughly 8.3 percent of all impervious cover in the Region. It would also likely require the removal and buyout of large portions of existing private development. Removal or relocation of this magnitude may be infeasible in a reasonable timeframe.
Land capability Class 1b lands and impervious surfaces within the Tahoe Region.
- This indicator measures the percent of land coverage on different land capability classes as described by Bailey (Bailey, 1974) and updated with the most recent soil survey by the Natural Resources Conservation Service (NRCS) in 2007 (Loftis, 2007; USDA-NRCS, 2007). Impervious cover is a primary indicator of land disturbance. Excessive impervious surface within a watershed contributes to sediment and nutrient inputs to Lake Tahoe and its tributaries impairing water quality, altering surface hydrology and groundwater recharge regimes. The results are often negative impacts on soil health, fisheries, wildlife habitat, and vegetation growth. Impervious surfaces include hard coverage such as roads, buildings, driveways, and parking lots, and soft coverage with soil compaction as a result of use, but where no structure is in place.
- Impervious cover is created through use or development on natural lands. This could be for commercial, residential, recreational, and other activities, and encompasses the spectrum of human uses that involve physical modification of the environment. The economy plays a large role in the housing market and the business environment, which are both among the most important drivers of new land coverage in the basin.
EIP Action Priorities
-
Acquire Environmentally Sensitive Lands for Restoration and Protection
Since 2007, EIP partners have aquired over 1,150 acres of environmentally sensitive land for protection or restoration.
EIP Indicators
-
Impervious Coverage Retired
Between 2016 and 2019, EIP partners and private partners through projects retired (i.e., permanently remove from future use) 41,546 square feet (0.95 acres) of Class 1b coverage.
Example EIP Projects
-
Clancy-Pohl Sensitive Land Acquisition
Nevada Division of State Lands used excess coverage mitigation funds to purchase this parcel and retire the coverage, including Class 1b coverage.
- Impervious cover within each land capability class was determined by an analysis of LiDAR/multispectral data collected in 2019. Land capability class 1b exceeds the target by 685 acres (601%) and is rated “considerably worse than target”.
- The trend for Impervious cover within Class 1b was determined to be "little or no change". TRPA Regional Plan policies limit new the amount of additional coverage that is allowed in sensitive land classes. And, the restoration, acquisition, and retirement of sensitive lands are priority actions for the Environmental Improvement Program projects.
- Moderate. TRPA has used the best available science and technology over time to assess the Impervious Cover Threshold Standard, different imagery datasets (4-band IKONOS collected in 2002, LiDAR and 8-band multispectral collected in 2010 and 2019). However, because of variation in the methods used to assess impervious surface features and estimate impervious cover, the comparison across evaluations is unsuitable.
- Moderate. There is “moderate” confidence in the current estimates of impervious cover from the LiDAR data and the resulting impervious surface layer. There is "high" confidence in the reporting of added coverage from permitting activities and coverage removal results from Environmental Improvement Program reported in the EIP Project Tracker.
- Moderate. There is “moderate” overall confidence base on the accuracy assessment of the impervious surface data and the land capability class results.
No documents available.