Save Our Canyons would like to offer the following comments regarding issues of slope and stream setbacks. As a short preface to the comments, Save Our Canyons would like to remind members of the Mountainous Planning District of the strong public support for the existing FCOZ ordinance. The Wasatch Canyons Tomorrow study released in 2010 found 82% public support for enforcement of FCOZ and for restricting variances that circumvent FCOZ’s protections including provisions preserving aesthetic qualities and limiting environmental degradation.
Since the release of the Wasatch Canyons Tomorrow study there’s been no indication that public support for the provisions of FCOZ has waned. On the contrary, the Central Wasatch Visitor Study recently conducted by Utah State University and Save Our Canyons has shown that the public’s commitment to seeing the Wasatch Mountains protected from additional development has only grown (https://extension.usu.edu/iort/files/uploads/Follow_Up_Survey_CWVUS.pdf).
While making decisions affecting our watershed it’s critical to keep in mind that as future drought and climate change impact the Wasatch Front, as is projected, the value of the watershed protected by FCOZ will both continue to grow and become more delicate. As such, the regulating of our Wasatch watershed for the protection of water quality which first began in the 1850’s is only becoming increasingly important as we face the complicating factors of scarce snow and water along with increased recreational use and development pressures. (. 12/04/15. )
While studies of slope stability in the Wasatch Mountains and foothills are too numerous to fully enumerate here, we do feel that key points from these various studies should be brought to your attention. Similarly for the issue of stream setbacks, there exists reams of documents studying ideal setbacks for water quality as well as aquatic and terrestrial habitat. Below we offer bullet points highlighting key findings on these two vital issues. The full studies and articles from where these bullet points were drawn can be found online and we would be happy to provide hard copies should commissioners be interested.
A quick google search reveals multiple stories about land and rockslides in and around the Wasatch Mountains and foothills. What constitutes a buildable slope is a matter of incredible importance and one that has serious ramifications for public safety.
- “Most unstable slopes are found in the canyons easton the city, along the steep flanks of Lake Bonneville deltas and in the bluffs around incised streams… In Salt Lake County, 56 percent of all slope failures have occurred on hillsides where slopes can range between 31 and 60 percent. The statistics prompted Salt Lake County in 1986 to lower the maximum allowable buildable slope from 40 percent to 30 percent. Even so, 23 percent of observed slope failures have occurred on slopes of 30 percent or less.” ( 32, Engineering Geology of the Salt Lake City Metropolitan Area, Utah. Bulletin 126. Edited by William Lund )
- Seventy-seven percent (77%) of all landslides in Salt Lake County occur on slopes steeper than 30%, and 58 percent are on slopes steeper than 40% (Figure 1). By subtraction, 23 percent of landslides in Salt Lake County would therefore be on slopes deemed buildable under current Salt Lake City zoning regulations. The Salt Lake County data also show a distinct increase in landslides above the 30% slope break, with landslide frequency in the three slope increments between 31% and 60% (18.7%, 19.3%, and 18.0%; respectively) being almost double the previous two increments (at 9.7%; Figure 1, right). Fifty-six percent (56%) of landslides in Salt Lake County occur in 31% to 60% slopes, a statistic which prompted Salt Lake County in 1986 to lower its maximum allowable buildable slope from 40% to 30% (Lund, 1990). ( A-4, Diagnosis: Salt Lake City Zoning and Development Standards for Foothill, Hillside, and Slope Areas, Bear West Consulting Team, March 2008)
- “Landslide data for Salt Lake County and western Wasatch County show an increased risk for land sliding above the 30% slope break. For Salt Lake County, over 75 percent of all mapped landslides are in slopes steeper than 30% and 56 percent of the landslides are in 31% to 60% slopes…. Based on the above, the 30% slope break appears to be a prudent gradient to efficiently reduce landslide risk in steep slope areas of Salt Lake City. Twenty-three percent (23%) of the landslides in Salt Lake County are in gentler slopes below 30%. Assuming the landslide risk is correlative to their frequency at various slope gradients, this frequency represents the inherent hazard risk. Decreasing the slope cut off to 20% only reduces the risk to about 14 percent, whereas increasing it to 40% increases the risk to 42 percent. Given the past historical damage caused by landsliding in Utah, and in Salt Lake City, such an increase in risk may not be desirable.” ( A 4-5, Diagnosis: Salt Lake City Zoning and Development Standards for Foothill, Hillside, and Slope Areas, Bear West Consulting Team, March 2008)
- “We recommend for several reasons that the slope development limit not be relaxed beyond 30 percent. First, the report submitted as part of this project by Western Geologic (Appendix A) confirms that 77 percent of all landslides in the county occur on slopes steeper than 30 percent. Moreover, landslides in the county have caused millions of dollars in damages to public and private property, roads, and utilities. For that reason alone, we believe that the city is on firm grounds in rejecting suggestions to weaken the slope standards. Second, the claim that steep slopes can be engineered and built on safely ignores the many other legitimate and strong rationales to continue to restrict steep slope development. These include fire safety (both for residents and firefighters), wildlife habitat projection, water quality and storm water management, and community aesthetics, among others. ( 11, Diagnosis: Salt Lake City Zoning and Development Standards for Foothill, Hillside, and Slope Areas, Bear West Consulting Team, March 2008)
- “The 100-foot zone was chosen based on the characteristics of the canyon as a whole. The steep slopes allow for abrupt land coverage changes and, therefore, a 100-foot buffer reduces possible overlap between riparian zones and other types of vegetative cover.” (Pg, 37, Wasatch Canyons Tomorrow, 2010)
Public Policy Research Series, University of Georgia: The following bullet points are from the same source which in seeking to guide the creation of effective local riparian buffer ordinances worked to establish a strong scientific foundation by reviewing the “research that has been conducted on riparian buffers, carefully analyzing some 140 scientific articles and publications.” This document, created as part of the Public Policy Research Series from the University of Georgia, endeavored to use an exhaustive scientific literature review to identify best practices that could be used by local governments across the nation for establishing effective stream and river corridors. (Wenger, S. and L. Fowler. 2000. Protecting stream and river corridors: creating effective local riparian buffer ordinances. Athens, GA: Public Policy Research Series, Carl Vinson Institute of Government, University of Georgia. http://www.ohioenvironmentallawblog.com/uploads/file/UGA%20riparian_buffer_guidebook.pdf)
- Pollutants: “The widths necessary for removing nitrogen vary based on patterns of water flow, soil factors, slope, and other variables. In most cases, 30-meter (100- foot) buffers should provide good control, and 15-meter (50-foot) buffers should be sufficient under many conditions.” (pg 9)
- Wildlife Habitat: ”Riparian buffers themselves constitute important terrestrial habitat, and the quality is directly correlated with width. While narrow buffers offer considerable habitat benefits to many species, protecting diverse terrestrial riparian wildlife communities requires some buffers of at least 100 meters (300 feet). To provide optimal habitat, buffers should consist of native forest.” (pg 9)
- Economic Benefits: “It is apparent that the economic benefits of buffers are at least of a magnitude comparable to their costs. In the future, we can expect the economic balance to tilt even more in favor of protecting riparian zones and other natural resources. Technological advances are steadily reducing the costs of agricultural and industrial goods, but the same cannot be said of natural features such as riparian zones. Therefore, in terms of goods and services produced from the agricultural and industrial sectors, the natural environment is becoming increasingly valuable (Bollman 1984). It makes economic sense to preserve these areas and locate extractive or destructive uses elsewhere when possible (Bollman 1984). (pg. 52)
- Effect of Slope on Stream Setbacks: The scientific literature shows that stream buffers should be increased in cases of steep slopes. “Studies suggest that long-term trapping of sediment requires much wider buffers. It appears that a 30-meter (100-foot) buffer is sufficiently wide to trap sediment under most circumstances, although buffers should be extended for steeper slopes.” (pg. 8) According to literature review, the best options for creating meaningful riparian buffers include the following criteria: Basic stream setback width, plus an additional 2 feet (.61 meters) for every 1 percent slope; slopes of 25 percent do not count towards setback. (further discussed on pgs. 11-13)
Huron River Watershed Council: The following are from a document created by the Huron River Watershed Council (HRWC) to aid cities and counties around the nation in crafting riparian buffer ordinances based upon the best available science. In addition to summarizing the science behind its ordinance, the HRWC provides a Model Ordinance for Riparian Buffers. Based on an extensive review of scientific literature, the HRWC recommends establishing and maintaining vegetated buffer systems at least 100 ft wide on each side of the waterway in order to meet the goals: “Protect and improve water quality, attenuate flows, stabilize streambanks, remove sediment, moderate stream temperature, protect and improve the abundance and diversity of indigenous fish and wildlife.” (pg 18 (pg 29, Riparian Corridor Protection in the Huron River Watershed. http://www.hrwc.org/wp-content/uploads/2009/11/HuronBufferPaper_Mar08.pdf)
- Water Quality: ”The preponderance of peer- reviewed scientific literature concerning vegetated riparian buffers supports establishing and maintaining buffers at least 100 ft wide on each side of the waterway for the purposes of intercepting sediment and nutrient pollution, maintaining stream temperature, protecting streambanks from erosion, moderating stormwater flows and flooding, and providing wildlife habitat”
- Wildlife: ”Recommended minimum buffer widths on both sides of a stream range from 100 ft for herpetiles to 600 ft for avian migrants such as bald eagles and sandhill cranes (Table 3). Wildlife ecologists recommend minimum buffer widths beyond 600 ft to meet habitat needs of larger migratory mammals. Buffer widths towards the lower end of the 5-30 m (16-100 ft) range tend to protect the physical and chemical characteristics of the stream, while protection of ecological integrity requires widths at the upper end of the range.” (pg. 20)
- Takings Issues Related to Stream Setbacks: The HRWC also discusses takings issues as some cities and counties may be tempted to weaken setbacks for fear of takings claims by private landowners.
- “Courts have clearly demonstrated that laws designed to protect water quality or even the environment in general are justified in the interest of public health, safety, and welfare (Witten 1997, Zoeckler 1997). In the case of Lucas v. South Carolina Coastal Council (1992), the U.S. Supreme Court noted that uses of property may be denied if they constitute a public nuisance, in accordance with long-established common law (Patterson 1993). Since nonpoint source pollution of water may constitute a public nuisance and riparian buffers are effective at preventing such pollution, the buffers may be protected from takings claims on these grounds as well.” (pg 29, Riparian Corridor Protection in the Huron River Watershed. http://www.hrwc.org/wp-content/uploads/2009/11/HuronBufferPaper_Mar08.pdf)
- Effect of Slope on Stream Setbacks: ”Furthermore, the width requirement needs to be modified if steep slopes are present within 500 feet of the stream. HRWC supports the width adjustments presented by the USDA, NRCS in its technical guide for riparian forest buffers in Michigan, which are presented in Section 7 of the Model Ordinance and here. The widths shown in the table below are in addition to the 100 ft width on each side of the waterway.” (pg. 18
Yale School of Forestry: The following study was prepared by the Yale School of Forestry and Environmental Studies to inform the Watershed Management Plan for the Eight Mile River, a watershed in Connecticut. (Hawkes and Smith. Riparian Buffer Zones: Functions and Recommended Widths Yale School of Forestry. http://eightmileriver.org/resources/digital_library/appendicies/09c3_Riparian%20Buffer%20Science_YALE.pdf)
- Pesticides: “Buffer widths for pesticide removal range from 49 feet to 328 feet.” (Pg. 5). This is applicable due to Snowbird’s request for agricultural uses at the resort.
- Aquatic habitat: “The minimum width of riparian buffers to protect aquatic wildlife, including trout and invertebrates, range from 33 feet to 164 feet.” (Pg. 5)
- Erosion: Erodibility of soil type is a key factor when assessing adequate buffer widths. Widths for effective sediment removal vary from only a few feet in relatively well drained flat areas to as much as several hundred feet in steeper areas with more impermeable soils. In order to prevent most erosion, vegetated buffers of 30 feet to 98 feet have been shown to be effective.” (pg 4)
- Effect of slope on stream setbacks: “As slope increases, the speed at which water flows over and through the buffer increases. Therefore, the steeper the land within the buffer, the wider it needs to be to have time to slow the flow of water and absorb the pollutants and sediments within it. Many researchers suggest that especially steep slopes serve little value as a buffer, and recommend excluding areas of steep slope when calculating buffer width. The definition of “steep” varies from over 10% to over 40% slope.” (pg. 6)
Environmental Economics: A Case Study for the Big Cottonwood Canyon Watershed: The following bullet points are taken from a thesis by a student at Claremont College. The thesis, “Environmental Economics: A Case Study for the Big Cottonwood Canyon Watershed” (2013), sought to identify the value of ecosystem services provided by the watershed so as to allow for better decision making in the process of regulating the watershed. While focusing the argument on SkiLink, the thesis assesses the costs and benefits of ecosystem services in a manner relevant to discussion of future regulation of the Wasatch Canyons.
- Water supply is a vital ecosystem service provided by the Big Cottonwood Canyon Watershed. The water supply service encompasses water availability and water quality, a major concern for the well-being of Salt Lake City residents. As noted, runoff leaving Big Cottonwood Canyon accounts for 22% – 24% of the water supply for residents surrounding the watershed area, the largest share of water supplied by the Salt Lake City watersheds. (pg. 17)
- While it has been alluded to above, the connectivity of ecosystem services merits further discussion. Each service is not independent of the others. Instead, the services work together to create a healthy and functioning ecosystem. Water quality depends on healthy soils, diverse plant life, and natural drainage. Other services are equally reliant on similar connections. The connectivity is extremely important and allows ecosystems to survive, but it is also cause for serious concern. Destruction and degradation of natural lands and their associated ecosystem services plays into this connective idea. Small, incremental damages may represent little marginal loss in the normal functioning of the services, but there is a tipping point. In other words, full collapse does not require complete and absolute destruction of an ecosystem. The incremental damages may reach a point in which one service loses its ability to function properly. As this service stops, many of the services connected to it will begin to stop functioning properly as well, depending on the level of connectivity. If, for example, a major service like biodiversity were destroyed to a point of failure, nonlinear and widespread collapse of the ecosystem services in the surrounding area could occur, resulting in a total loss, not merely a marginal loss. For this reason, the protection of natural lands from development is paramount. (pgs. 17-18)
- Conservation of the ecosystems that contribute to water supply is more cost effective than replacing or fixing the service once it has been lost or altered. For example, conserving an upstream forest to protect water quality will often be cheaper than building or upgrading water treatment plants. Studies in Oregon, Maine, and Washington have found that every $1 invested on watershed protection measures saves $7.50 to $200 in water treatment facility costs. New York City’s Catskills Range protection measures have saved the city $4 to $6 billion on infrastructure that would have otherwise been required to maintain water quality supplied to its residents (Emerton and Bos, 2004). Furthermore, watershed protection measures focused on preserving forest cover can prevent unnecessary treatment costs, according to Ernst, Gullick, and Nixon’s study covering data reported by 27 water utilities across the nation. Specifically, for every 10% increase in forest cover, treatment costs decrease by approximately 20% for water suppliers (2004). (pg 19)
- As disturbance regulation control measures are degraded, destroyed, or altered, the ecosystem service loses its ability to control water flow. Natural capital that has been manipulated by development contributes to increasing runoff volume and speed, intensifying peak flows (Schmidt and Batker, 2012). As a watershed loses the complexity of its land cover, disturbance regulation declines in value. Healthy watersheds that include multiple land types are crucial to disturbance control and mediation. This is of particular importance in Big Cottonwood Canyon due to its narrow streambed and steep slopes. Without disturbance regulation, road and property repair could prove to be costly. A history of damaging floods in the canyon adds to the importance of sustaining this ecosystem service. (pg 24)
- Analyzing estimates from the studies described above, benefit transfer methods are used to total the values of the services described in the Other Ecosystem Services section based on land type (2012 dollars) (Table 3). These total values are based on previously researched values from studies in which ecosystem service characteristics were similar to those found in the Big Cottonwood Canyon Watershed. For Big Cottonwood Canyon, forested areas contribute $232.99 – $1,484.86 per acre per year to these services. Scrublands contribute $3.32 – $8.14 per acre per year, while wetlands contribute $1,546.86 – $8,035.73 per acre per year. Finally, riparian buffer zones provide services with a value of $489.72 – $922.67 per acre per year. (pg. 40)
- Over a 50-year time period, the “assett value of the watershed totals $1.02 billion to $3.07 billion. (pg. 46)
- One final and important consideration is the added pressure SkiLink may put on the canyon for future housing development. Developments near other resorts in different Salt Lake City canyons have been moving forward. For example, Snowbird Ski & Summer Resort in Little Cottonwood Canyon is hoping to expand with a new subdivision, and that resort is receiving opposing arguments similar to those waged against SkiLink (Gorrell, Mike, 2012). The development precedent represents a major argument against SkiLink. As previously noted, it is difficult to pin down the tipping point associated with nonlinear ecosystem collapse. If SkiLink creates a prolonged influx of skiers to the area, as the proposal believes it will, pressures to expand ski resorts and increase lodging amenities would likely follow. These added developments, if allowed, might ultimately spell disaster for the watershed. It is important to note that the same valuation methods used to analyze the SkiLink proposal could be implemented on future development options to decide if their added economic benefits trump the ecological losses. Considered in isolation, SkiLink does not represent severe environmental damage, but it sets a dangerous precedent for canyon development. (pgs. 53-54)