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This indicator measures the restoration of stream environment zones (SEZ) in the undeveloped portions of the Tahoe Region. Prior to TRPA regulations that limit development in SEZ, these lands outside of developed areas were degraded through harmful activities like grazing and damming. SEZ plays critical roles including natural water filtration, storage, and conveyance of surface runoff. Naturally functioning SEZ also provides open space, flood flow capacity, riparian vegetation, and fish and wildlife habitat. Both completed and planned projects in the Environmental Improvement Program, are restoring SEZs. SEZ restoration is tracked, and SEZ conditions are monitored by EIP partners and TRPA.
- Status
- Somewhat Worse Than Target
- Trend
- Moderate Improvement
- Confidence
- Low
- This standard is based on a 1982 baseline condition that was not recorded at the time the standard was adopted. It is therefore not possible to assess this standard's progress since 1982. Nonetheless, identified but not yet implemented SEZ restoration projects account for the attainment status of "Somewhat Worse Than Target."
- TRPA and partners completed the first-ever comprehensive Stream Environment Zone (SEZ) baseline condition assessment in 2020.
- The 2020 baseline assessment identified hundreds of acres of SEZ in undeveloped areas that are impacted by historic disturbance (e.g. logging, grazing), and are candidates for enhancement or restoration.
- For threshold reporting, SEZ restoration totals are not tracked separately for developed and undeveloped areas, only as total SEZ restoration. (See also: impervious cover indicator for Class 1b).
Stream environment zones in the Tahoe Region and their rating. "A" rating is excellent condition, "B" is good condition, "C" is degraded condition, and "D" is very degraded condition.
- This indicator measures the protection, restoration, and enhancement of stream environment zones (SEZ). SEZs play a variety of critical roles including 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. SEZ protection and restoration can also contribute to the achievement of other environmental threshold standards, including water quality, wildlife, fisheries, vegetation preservation, recreation, and scenic resources. Even seemingly unrelated threshold standards such as air quality and noise are affected by SEZs. For instance, aspen stands in SEZs next to roadways have been shown to moderate roadway noise and help block particulates from spreading to adjacent areas.
- Disturbance and degradation of SEZs in the Tahoe Region began in the 1800s through logging, grazing, stream, and river channelization, development, damming, fire suppression, and other activities, with environmental consequences that are still evident today. Higher temperatures and altered precipitation regimes forecasted as a result of climate change further threaten to alter the dynamics of SEZs in the basin.
EIP Indicators
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Acres of SEZ Restored or Enhanced
This EIP performance measure tracks the amount of SEZ that is restored or enhanced by EIP partners to regain natural or historic function and values.
Example EIP Projects
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High Meadows/Cold Creek Restoration
This project completed by the USDA Forest Service restored 110 acres of SEZ along Cold Creek in the High Meadows area.
- The current was determined based on the SEZ baseline condition assessment that was completed for the Tahoe Basin in 2020. This assessment rated the condition of all SEZ in the Tahoe Basin as of 2020 as 86% of the total possible score. There is not a formal delineation or definition of "undeveloped" SEZ, but there are numerous restoration and enhancement opportunities identified outside urban boundaries. Therefore, it was determined that this threshold is not in attainment.
- The standard has neither a specific target (undeveloped is not defined) nor a baseline against which to measure progress, thus the exact trend cannot be quantified. The number of acres of SEZ restored or enhanced over the last 40 years, and the benefits of those restoration projects were clearly documented in the baseline assessment. Going forward, a trend will be able to be determined based on the baseline conditions established in 2020.
- High. The 2020 SEZ baseline condition assessment was completed using the best scientific evidence and although there is no definition of "undeveloped" areas, there were numerous SEZ outside of urban areas are still degraded.
- High. There is high confidence in number of acres of SEZ restored or enhanced over the last 40 years, and benefits of restorations projects was clearly documented in the baseline assessment.
- High
No photos available.
No documents available.
SEZ Baseline Condition Assessment - An assessment of the current conditions of Stream Environment Zones (SEZ) throughout the Lake Tahoe Basin. Tahoe Regional Planning Agency - Funded through a United States E.P.A. Wetlands Development Grant. December 15, 2020.