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Travel Route Ratings for Shoreline Travel Units

Status and Trend

Interpretation and Commentary

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Status: At or Somewhat Better Than Target
Trend: Little or No Change
Confidence: High

  • Relevance - This indicator tracks long-term, cumulative changes in scenic conditions along the shoreline of Lake Tahoe. It accounts for developed and natural-appearing shoreline areas. Tracking these changes is important because it provides a measure of how changes in land use and development affect scenic conditions over time. By 1996, scenic conditions along Lake Tahoe’s shoreline had declined to levels below what they were in 1982. By 2006, after adoption of new development regulations for shoreline projects, conditions began to improve. The trend has been toward continued improvement in conditions since 2001.
  • Adopted Standards  - To secure Threshold Standard attainment, the composite score of those shoreline travel routes with a 1982 score of 7.5 or greater must be maintained at the level they were in 1982, and the composite score of all shoreline travel routes with a 1982 score of seven or less, must improve until the minimum score of 7.5 is reached.
  • Indicators - Shoreline Travel Unit Composite score, which is a unit-less, numerical rating consisting of the sum of the ratings given to three different aspects of the landscape within each travel unit.
  • Status – As of 2011, 21 of the 33 (64 percent) Shoreline Travel Units were determined to meet the unit-specific Threshold Standards while 12 (36 percent) did not. Of the 33 units, it was determined that zero percent are “considerably better than target,” 64 percent are “at or somewhat better than target,” 27 percent are “somewhat worse than target,” and nine percent were “considerably worse than target.” When scenic evaluation units were aggregated according to the methods outlined in the methodology section of this report, the overall average aggregation scores for shoreline travel units was = 0, resulting in a determination of “at or somewhat better than target.”
  • Trend – In 1982, when Scenic Threshold Standards were first adopted, there were four shoreline travel unitsout of a total of 33 (12 percent) that did not meet the minimum standard. It was determined in 2011 that zero percent of the 33 units were in “rapid improvement,” three percent were in “moderate improvement,” 94 percent were in “little or no change,” three percent were in “moderate decline,” and zero percent were in “rapid decline.”  When scenic evaluation units were aggregated according to the methods outlined in the methodology section of this report, the overall aggregation score for trend in roadway travel units was = 2, resulting in a determination of “moderate improvement.”  From 1982 through 1996, scores for shoreline travel units were generally declining. Chapter 30 of the Code of Ordinances was amended in 2002 to include what is known as the Shoreland Ordinance to address this issue. Since then, scores for shoreline travel units have been generally improving.

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  • Confidence
    • Status - A documented, reviewed, and accepted monitoring protocol was used to guide the collection, analysis and reporting of the scenic monitoring data. It was collected according to procedures outlined in the 1982 Study Report for the Establishment of Environmental Threshold Carrying Capacities (TRPA 1982b), and Status and Trend Monitoring Report (DRAFT) for Scenic Resources in the Lake Tahoe Basin (TRPA 2010), which set forth a methodology for measuring change in scenic quality over time. The methods are consistent with those employed by the U.S. Forest Service, and are considered standard practice. This equates to a “high” confidence determination for status.
    • Trends -  Basin-wide monitoring of travel route ratings occurred in 1971, 1982, 1986, and as part of the 1991, 1996, 2001, 2006, and 2011 Threshold Evaluations. This represents the most extensive and well-documented chronology of change to resources available within TRPA’s entire environmental Threshold Standard evaluation system. Consequently confidence in trend determination is “high.”
    •  Overall Confidence - Because there is high confidence in the determination of both status and trend, a “high” determination is assigned to the overall status and trend determination.
  • Human and Environmental Drivers - The primary drivers affecting scenic quality in the shoreline areas of Lake Tahoe are land use, and the visual exposure and visual/aesthetic characteristics of development.
  • Monitoring Approach – Field surveys (using established protocols) are conducted every five years by a team of qualified professionals to examine and evaluate scenic conditions along the shoreline of Lake Tahoe, major roadways in the Basin, and at public recreation sites and bike trails. Ratings from prior evaluations are reviewed. Updated ratings are assigned as warranted based on current conditions.
  • Monitoring Partners – U.S. Forest Service and Tahoe Regional Planning Agency


  • Monitoring Plan
  • Conceptual Model


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Map showing the distribution of shoreline travel unit Threshold Standard status in the Lake Tahoe Region, 2011. (Source data: TRPA Scenic Threshold Monitoring Data).

Trend Charts

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Change in overall average Shoreline Travel Unit Rating by year, 1982 to 2011 (adopted minimum Threshold Standard is 7.5).

Additional Info


Additional Information

Last Updated on Wednesday, 12 September 2012 08:58