Sherry Hazelhurst, Hydrologist

USDA Forest Service, Lake Tahoe Basin Management Unit

Phone: (530) 573-2655

Heavenly Ski Resort lies in the southeastern corner of the Lake Tahoe Basin, on the east slope of the central Sierra Nevada mountains. Encompassing about 4,000 hectares in California and Nevada, the resort is one of the largest in the area operated on National Forest System lands. Emerald and sapphire waters of Lake Tahoe shimmer in the sun, reflecting upward onto Heavenly’s snow capped peaks. The Lake’s designation as an Outstanding Natural Resource Water affords strict water quality standards for its tributaries, including those originating from Heavenly. Consequently, maintaining water quality at the resort is a high priority, and has been the focus of traditional monitoring programs. After analyzing eleven years of water quality data on one creek, results indicate that suspended sediment and nutrient concentrations were affected by ski resort development, however specific causes were lacking.

Heavenly has been a Special-use permittee of the US Forest Service since 1955. To date, there are approximately 628 acres of ski runs, 25 ski lifts, and 30 miles of roads within the resort (Heavenly 1996). Many run surfaces were created by bulldozing a swathe down steep hillsides, resulting in removal of all vegetation, rocks, woody debris, and often a loss of the shallow topsoils. Numerous roads were also built to install lifts, interrupting drainage patterns with bare, compacted surfaces. The loss of soil cover and alteration of the topography caused accelerated erosion throughout the resort, although the relative contribution from individual sources was not identified through water column analyses. Similarly, beneficial effects of revegetation and other mitigation projects prior to 1991 could not be detected using traditional monitoring.

Regulatory agencies and the public are demanding quantitative data showing ecosystem condition at Heavenly. Compliance with state standards and the ease of obtaining water samples have been the primary reasons for emphasis on measuring water quality. These monitoring results show the cumulative effect of management on Heavenly Valley Creek, however, many questions regarding other watersheds and ecosystem processes within them remain unanswered. Recent planning efforts at Heavenly allowed the Forest Service and other interested parties to adapt the traditional monitoring program by expanding its scope to include a more holistic sampling of the ecosystem.

A steering committee, including representatives from regulatory agencies and Heavenly, was asked to show how past and future development and mitigations may impact water quality and ecosystem processes at the resort. Current conditions were addressed in the Master Plan (Heavenly 1996) and Environmental Impact Statement (USDA FS 1996a).

Water quality data for the period-of-record, 1981 through 1991, was analyzed to illustrate nutrient and sediment concentrations relative to state standards. Heavenly Valley Creek, the largest watershed at the resort, originates from springs on the upper California side and drains about 531 hectares. Water quality had been monitored at three stations, the most reliable of which was Patsy’s (elevation 2,444 m). This station depicts cumulative effects fairly well because it is located just below ski area development in the watershed. Sample collectors and water analyses varied over this period, so some constituent values were missing and others were extrapolated using a larger data set.

Analysis showed that nutrient and sediment concentrations were often greater than the state standard, with a trend toward increasing values. Table 1 displays annual average concentrations of total Nitrogen (N), total Phosphorus (P), and suspended sediment. State standards for these constituents were exceeded in 7, 11, and 6 years, respectively, between 1981 and 1991. Soluble reactive phosphorus (SRP) showed a similar increasing trend for the years sampled. SRP represents that fraction of P that is readily available for plant uptake. It is an important management indicator, since it is thought to be a limiting nutrient for planktonic algal production in Lake Tahoe (Goldman and Byron 1986; Byron and Goldman 1989).

Table 1 also shows that average flow began a significant decline in 1986, beginning a seven-year drought period. The drought likely affected nutrient and sediment concentrations beyond 1986, in that soils were less apt to detach from water erosion and lower stream flows were incapable of transporting large loads.

Physical and biological attributes of all seven streams draining the resort were assessed between 1990 and 1991. Channel stability was evaluated using the Pfankuch method (Pfankuch 1978). Most of the streams received fair to poor stability ratings. Common findings included bank cover lacking, sediment filling pools, downcutting, obstructions causing cutting, and ineffective project mitigations. A fisheries survey found that most of the stream area within the resort lacked migratory and resident fish populations due to downstream barriers and low instream flows during portions of the year. Some resident fish occurred in lakes, and mostly consisted of planted species (USDA FS 1996).

Upland conditions on Heavenly’s ski runs, roads, and structures were documented and quantified in the first attempt to illustrate an individual project’s effect on water quality. Developments were assessed for soil cover, drainage, infiltration, and best management practice application. The 68 runs and 30 miles of roads were field surveyed and divided into 385 and 395 segments, respectively. Soil loss was calculated for each segment using a modified version of the universal soil loss equation. Soil erosion rates ranged between 0.02 and 462 T ha^-1 yr^-1 on ski runs and 3.5 to 1070 T ha^-1 yr^-1 on roads. The average soil loss rate was 46 T ha^-1 yr^-1 from ski runs and 156 T ha^-1 yr^-1 from roads. Stream sedimentation for the run and road segments was then estimated using a sediment delivery model. Calculations show that ski runs contributed slightly more sediment to streams than roads, although significantly more soil erodes from road surfaces. Sedimentation rates averaged 2.7 T yr^-1 for ski run segments and 2.5 T yr^-1 for road segments. Maps illustrate the location of segments with the greatest sediment yield, and these segments were scheduled for mitigation. The mathematical models were also used to predict the outcome of prescribed measures.

Heavenly’s EIS was the first document to address physical, chemical, and biological impacts of ski area development on its ecosystem resources. Although the resort has over 40 years of operational history, much of the quantitative information regarding watershed condition had been speculative until this analysis. Data gathered during the EIS process provides a baseline against which future management may be measured. As such, the monitoring program needed to be revised to encompass a broader view of ecosystem processes. Heavenly’s planning process was guided by a steering committee comprised of members from Heavenly Ski Resort, USDA Forest Service, Tahoe Regional Planning Agency, El Dorado County (California), City of South Lake Tahoe (California), and Douglas County (Nevada). The steering committee asked Forest Service specialists to prepare a watershed monitoring program that would begin to track progress of past and future mitigations as well as development.

The first step in building a new monitoring program was listing all the questions that were being asked about watershed condition. Water quality remained a primary concern due to state standard attainment and cumulative effects measurement. Specific sources of water quality fluctuation had been less well monitored, thus more effort was needed to document these processes. The resulting program combines as many physical, chemical, and biological parameters as possible to gain a more holistic view of watershed processes. Soil cover, best management practices, and riparian conditions are three areas impacting water quality at Heavenly that were selected for additional monitoring. Each of these areas affects the others, so a condition and trend analysis ties all of the individual parts together to show interactions and opportunities for adaptive management.

Cover prevents highly erodible, bare soils from becoming easily detached and deposited into streams. There are several objectives for collecting information about the type, amount, and distribution of plants, organic material, and rocks on ski runs and roads. These measurements will be used to determine cover types and quantities most effective for preventing soil movement on a variety of slopes. Information from revegetated sites may begin to indicate favorable seed mixtures, fertilizers, irrigation regimes, and site preparation methods. Over time, plant successional patterns are expected to become clearer. Management practices and mitigation prescriptions will be adapted to enhance conditions most successful in preventing soil erosion. Finally, assumptions made in the erosion and sediment delivery models will be adjusted as needed.

Best management practices (BMPs) are measures used to prevent adverse water quality impacts from temporary or permanent soil disturbing activities. Numerous assumptions are associated with the planning, implementation, maintenance, and effectiveness of BMPs prescribed for all such projects. Monitoring these phases of BMP development is intended to identify both strong and weak points in the process, helping to improve success on subsequent projects.

Riparian areas function as transition zones between uplands and channels, linking terrestrial and aquatic ecosystem processes. Their position in the landscape often affords immediate and measurable effects from changes on either side. It is this sensitivity that makes riparian areas ideal for interpreting how management is affecting the ecosystem over both short and long temporal scales.

Condition and trend summaries unite observations from all watershed attributes monitored into a broad description of ecosystem processes. Inferences can be made about cause and effect relationships, and the data can show where positive and negative impacts are occurring. Further, this information can be used in future projects to create successful outcomes and correct shortcomings. Reports summarize all data collected annually, and a cumulative report will more thoroughly analyze data after five years.

The new monitoring program incorporates both quantitative and qualitative measures where appropriate. Attributes that can be measured with repeatability are quantified. Similarly, estimations, recommendations, photos, and comments can be taken almost everywhere. Both measures are expected to be useful for presenting facts, correcting problems, and showing changes over time. Such latitude to measure and describe various ecosystem attributes will enhance our understanding of how things are connected and work together.

Heavenly’s steering committee, other government agencies, and the public had opportunities to comment on draft versions of the monitoring program. These groups provided helpful insights that improved the final product. Heavenly made the commitment to begin monitoring in 1995, and the new program was adopted as part of the Master Plan in 1996.

Several years of mitigation projects and favorable growing conditions have resulted in improved ecosystem conditions throughout Heavenly. Monitoring over the past three years shows increases in soil cover and BMP effectiveness, with corresponding improvements riparian condition and water quality.

Half of all the ski runs assessed in 1991 have been reevaluated in the past three years. Soil cover on these runs ranges between 18 and 78%, and averages 57%. Vegetation and organic material cover an average 28% and 21% of the run surface, with the balance comprised of rocks. These values show increases of 10% total cover, 4% vegetation, and 6% organic material since 1991. Additionally, two miles of road have also been abandoned or obliterated, increasing soil cover and infiltration properties. Several common notes accompany these evaluations: soil cover should still be improved on most runs; concentrated flow from roads and other areas is entering run surfaces, often accelerating erosion; and waterbars or other drainage structures need to be repaired or added.

All permanent structures have been evaluated for applicable BMPs, and areas needing improvement have been identified. Sites have been ranked for treatment according to high, moderate, or low priority based on proximity to active channels and extent of erosion source(s). The highest priorities have been scheduled for implementation during 1998 and 1999. Common BMP needs at lifts and other structures include increasing plant, organic material, or rock cover and adding infiltration systems.

Construction sites have been monitored at least once weekly for BMP compliance. Temporary BMPs are required to be in place prior to soil disturbance and are evaluated by Forest Service and other agency officials. Monitoring has shown that most BMPs are applied correctly and are effective. Problems tend to develop if they are not maintained or if storms exceed the design limitations of the measures.

Riparian condition and channel stability have improved significantly over the past six years, particularly on Heavenly Valley Creek. Stream bank stability has improved dramatically, with 18 of 23 reaches, 74% of the channel length, rated good or excellent. Only 31% of the channel was rated good to excellent in 1990. Almost every reach showed improvement in the following ways: riparian plant vigor and density increased; more bed and bank materials stabilized; and there was less downcutting and bar development. Two, Rosgen AB@ type reaches (Rosgen 1996) have been intensively inventoried using Forest Service, Region 5 protocols (USDA 1996c). Both reaches had consistently lower pool depths and more fine particles in the pool tails than similar reaches in undeveloped watersheds. However, the upper reach showed signs of improvement with high sinuosity (1.46), low width to depth ratio (11), and an increasing number of pools. The lower reach was recovering from a large influx of sediment due to an earthen berm failure in 1995. Fish communities on this creek are still lacking within the ski resort, however macroinvertebrates are common.

Changes in soil cover, BMP effectiveness, and riparian condition are reflected in improved water quality. The drought beginning in 1987 lasted until 1994, with a brief reprieve in 1993. Nutrients and sediment would have been expected to increase to previous levels with the return of greater than average runoff after 1994. However, this was not the case. Figure 1 shows how nutrient and sediment loads measured from 1992 through 1997 decline proportionally with flow. It also illustrates the magnitude of change over the period-of-record. Suspended sediment loads dropped most dramatically during non-drought years, from a high of 1074 T ha^-1 yr^-1 in 1983 to a low of 26.8 T ha^-1 yr^-1 in 1996. Total N and P loads continue to decrease, with lows of x and y recorded. Annual average nutrient and sediment concentrations are also declining. Nitrogen was below the state standard in 2 of 6 years, while suspended sediment was always less (see Table 1). Total P values do not meet state standards at this site, nor at any other comparable sites in undeveloped watersheds. The regional water board is aware of this result, and will be reviewing data to revise the total P standards for all tributaries within the Lake Tahoe Basin. It is relevant to note that total P concentrations once averaged above 0.178 mg/L and is currently below 0.040 mg/L. SRP remains fairly constant throughout the period, with fluctuations probably limited more by dissolution in flow than in total P within the stream. Another constituent of note is turbidity. This measure of water clarity has improved 90%, averaging less than 2 ntu in each of the last three years following annual averages of 32 ntu in 1981 and 1985.

These preliminary results from the new monitoring program appear to be promising. Land management practices at Heavenly have improved over the last decade for a variety of reasons, not the least of which include new products, technologies, education, and commitment. The first steps have been taken, and we hope to see even greater improvement a decade from now. The broader perspective on processes is beginning to cast a new light on relationships among ecosystem elements. The Forest Service, Heavenly, and their other partners are learning so many new things that adaptive management is no longer a goal but reality.

Learning from our successes and failures sounds trite, however, monitoring emphasizes these lessons. We are probably most limited by the amount of time we can spend observing things. Almost instantaneous lessons can be learned during a significant event, such as a thundershower that causes runoff to breach a waterbar. Some lessons are apparent after a season’s worth of observation, such as seed germination success at a revegetated site. Still other lessons take longer periods of time to understand, such as plant succession and resulting impacts on water quality.

The temporal scales involved in these lessons affect the forms of feedback, and ultimately adaptive management, that is achieved. Fixing a breached waterbar may require verbally notifying a few people, and expecting a result in a matter of minutes or hours. Seed germination results over one season may be documented the first year and for several subsequent years, affecting revegetation projects for years to come.

Written reports provide everyone with the same information, improving group understanding and communication. The annual report provides a review opportunity for those conducting and using the monitoring results. Lessons shared can improve current and future planning efforts by demonstrating effective management tools and positive project outcomes. Reports also serve as a tracking device for identifying needed projects and highlighting accomplishments. Whether informally or formally noted, monitoring feedback can be used to adapt management practices over short or long periods. A critical step in the feedback loop is educating others about the things we have learned. This education phase is often a disconnect for many monitoring programs, particularly if the results go unrecognized by those for whom they are intended to help. One reason this monitoring program has been so successful is due to a strong and committed partnership.

Heavenly recognized the benefits of establishing partnerships with interested groups early in the planning process. Through mutual agreement, committees were formed tapping resources from many other agencies. The collaborative work of many groups including regulatory, governmental agencies, and universities provides a wide array of knowledge from which to make the best decisions possible. Cooperators receive a copy of the reports and meetings are held to discuss the issues presented. The five-year review period will occur in 2000 with the report analyzing changes in condition and trend throughout the resort. This review will offer the group a chance to evaluate the success of existing programs and rectify any shortcomings or redundancy.

A major beneficial effect of this partnership has been an improved relationship between Heavenly, various agencies, and the public. Frequent cooperator meetings and project site visits have fostered significant beneficial effects. There is greater respect and understanding among Heavenly’s employees, various agency specialists, and the public. Heavenly’s employees have higher awareness of environmental protection and land management, with particular regard for how their specific job duties affects such issues. The role of regulator is becoming easier since everyone has a vested interest in improve management outcomes. Removing the adversarial relationships has resulted in more open and productive discussions about problems that arise. Better solutions are being reached through consensus among trusting participants. Ultimately, the benefits of partnership are improving everything from inter-personal communication to ecosystem condition. I’m proud to work with such a dedicated group of people.

Byron, E. R. and C. R. Goldman. 1989. Land-use and water quality in tributary streams of Lake Tahoe, California-Nevada. Journal of Environmental Quality 18:84-88.

Goldman, C. R. and E. R. Byron. 1986. Changing water quality at Lake Tahoe: the first five years of the Lake Tahoe Interagency Monitoring Program. University of California, Davis, CA. 12 p.

Heavenly Ski Resort. 1996. Heavenly Ski Resort Master Plan. South Lake Tahoe, CA. 500 p.

Pfankuch, D. J. 1978. Stream reach inventory and channel stability evaluation. USDA Forest Service, Northern Region. Missoula, MT. 1978-797-059/31. 26 p.

Rosgen, D. L. 1996. Applied river morphology. Wildland Hydrology, Pagosa Springs, CO. 371p.

USDA Forest Service. 1996. Final Heavenly Ski Resort Master Plan EIR/EIS/EIS. South Lake Tahoe, CA. 4000 p.

USDA Forest Service. 1996b. Stream channel inventory protocols for Region 5. Version 3.4. USDA Forest Service, Pacific Southwest Region. San Francisco, CA. 80 p.