Ashland Forest Resiliency

Cumulative Watershed Effects Analysis Appendix I July 2008 Introduction The purpose of this report is to document the assumptions and results of the cumulative effects analysis completed for the Ashland Forest Resiliency Final Environmental Impact Statement (FEIS). This document provides the basis of assumptions used in analysis and modeling of cumulative watershed effects. It documents methodology and information that is more in technical than the summary of conclusions presented in the FEIS. On the Klamath National Forest (Forest Service Region 5), an approach entitled the Equivalent Roaded Area (ERA) Methodology (UDSA FS 1999) has been utilized for assessing relative risk of cumulative watershed effects. It is important to note that the scope of the analysis of existing conditions at the subwatershed scale is dependant on the nature of the historic and ongoing effects and the availability of data for the watershed being analyzed. In order to provide a consistent analysis for the entire Upper Bear Analysis Area, the ERA Methodology was used to assess the cumulative watershed effects of past, present, and reasonably foreseeable future activities in the Ashland Creek, Neil Creek, Hamilton Creek, and Upper Wagner Creek sub-watersheds. This method was selected because the data needed to run the ERA model was available and consistent throughout the watershed analysis areas. Recent environmental analyses completed by the Rogue River-Siskiyou NF has utilized a methodology referred to as the CWE Methodology. This model, sometimes referred to as the “Section 7” model, was used to aid in consultation with the National Marine Fisheries Service (NMFS) under Section 7 of the Endangered Species Act. The Forest Service developed the CWE Methodology for assessing the relative risk of adverse cumulative watershed effects in response to a request from NMFS (USDA FS 1993). Although, the CWE Methodology has been commonly used in Forest Service Region 6, this analysis uses only the ERA Methodology to assess past, current, and future activities. The cumulative effects analysis process described in this document is primarily based on information (data) from the Rogue River-Siskiyou National Forest Geographic Information System (GIS) databases. The analysis was primarily performed using ArcMap, a GIS software.

Background Cumulative effects analysis can be performed at various scales. For potential effects to be measurable, the sub-watershed scale was selected for analysis. Sub-watersheds are a subset of and smaller in area than watersheds and generally referred to as “6th field”. A sub-watershed, like a watershed, is an area of land that all drains to a point on a stream. Generally the location for this point is at a confluence with another stream. Watersheds are generally 40,000 to 250,000 acres in size and referred to as “5th field”. Subwatersheds are usually 10,000 to 40,000 acres in size.

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The Bear Creek Watershed (a 5th field watershed) totals approximately 361 square miles (231,087 acres). This watershed lies approximately 127 miles upstream from the Pacific Ocean at the extreme southeast corner of the upper reaches of the Rogue River Basin. The boundaries of the watershed are formed by a ridgeline which travels along the Cascade Mountains on the north and east sides and the Siskiyou/Klamath Mountains to the south and west. Ashland Forest Resiliency and the Upper Bear Analysis Area is located within four separate subwatersheds, described in FEIS analysis as the Ashland Creek sub-watershed, the Neil Creek subwatershed, the Hamilton Creek sub-watershed and the Upper Wagner Creek sub-watershed, all within the Bear Creek Watershed and the Rogue River Basin. The geographic extents of the sub-watersheds for this report are depicted on Map I-1. The Ashland Creek sub-watershed is approximately 24.7 square miles (15,785 acres) in size and is one of the primary tributaries to Bear Creek. This analysis area includes all of the hydrologic area of the Ashland Municipal Watershed. This watershed extends from the summit of Mt. Ashland on the south to the confluence of Ashland Creek and Bear Creek on the north. The Neil Creek sub-watershed also contributes flow to Bear Creek, and this 21.2 square mile (13,563 acre) sub-watershed is located on the east side of the Upper Bear Analysis Area. The lower boundary of the Neil Creek Watershed is located at the confluence of Neil Creek and Bear Creek. Near the boundary of the Rogue River National Forest, the slope of the valley floor decreases dramatically. Downstream from the National Forest boundary is primarily pasture or rural developed lands. Several other small streams contribute to this sub-watershed. The Upper Wagner Creek sub-watershed is located in a generally north facing basin that is 9.2 square miles in size (5,875 acres). The lower extent of the Upper Wagner Creek watershed the same as the Upper Bear Analysis Area boundary, at the confluence with Wagner Creek Horn Gulch Creek, which is in proximity to the National Forest boundary. The sub-watershed is a mix of interspersed privately owned and Federally managed lands. Wagner Creek flows to the north and into Bear Creek near the city of Talent. The 6.5 square mile (4,127 acre) Hamilton Creek sub-watershed is a north facing drainage immediately to the south of the City of Ashland. The northern end of the Hamilton Creek Watershed is located at the confluence of Bear Creek and Hamilton Creek. The majority of this sub-watershed is located on privately owned land and is mostly within the city limits of Ashland. Note that there is a small area in the northwest corner of the 2003 Upper Bear Analysis Area that is not included in one of the four sub-watersheds. This area is not being analyzed here because no actions are proposed to occur within this small area. Because there are no actions proposed, there would be no cumulative effect.

Equivalent Roaded Area Methodology The ERA Methodology utilizes GIS analysis of land use activities to convert road, timber harvest, fire, and other disturbances within each watershed to equivalent roaded areas based on predetermined coefficients that are regionally specific. The resulting equivalent roaded area within each watershed is divided by the area of each watershed to calculate a relative disturbance rating, which is called the percent ERA. Then, the percent ERA is compared to the Threshold of Concern (TOC) for each watershed. Finally, the calculated TOC is compared to the percent ERA for each watershed to determine a watershed Risk Ratio. The following discussion describes the process and displays the values for each sub-watershed analysis area. FEIS APPENDIX I Cumulative Watershed Effects Analysis

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MAP I-1. Sub-Watershed Analysis Areas

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Equivalent Roaded Area (ERA) Coefficients To determine ERA, coefficients for disturbance classes are compared to values for roads to calculate the area of road that would produce the same change in peak flows. The information is used to create a table of Equivalent Roaded Area coefficients. Coefficients have been adjusted over time based on experience by resource specialists. Satellite imagery was used to develop a disturbance map for the affected sub-watersheds. Various vegetation classes from the imagery were assigned an ERA coefficient (see Table I-1.). Refer to the cumulative effects analysis performed for the Mt. Ashland Ski Area Expansion FEIS for a discussion on how the coefficients were derived. The following table displays the coefficients used to model the satellite imagery on the Analysis Area: Table I-1. ERA Coefficient by Vegetation Type Description Greater than 60% canopy closure, greater than 24” DBH Late seral forest Less than 60% canopy closure, greater than 24” DBH Greater than 60% canopy closure, 11 - 24” DBH Mature forest Less than 60% canopy closure, 11 - 24” DBH

Immature forest

Seedling/sapling

Greater than 60% canopy closure, 6 - 11” DBH Less than 60% canopy closure, 6 - 11” DBH 0 – 6 “ DBH

Shrub/grass/forb1 Barren2 Roads Non-erodible Private

Includes lands outside NFSL that are not otherwise mapped in another category

ERA Category Within NFSL - Undisturbed Outside NFSL – Moderate disturbance, 0-20 years old Within NFSL - Moderate disturbance, 20-30 years old Outside NFSL – Moderate disturbance, 0-20 years old Within NFSL - Undisturbed Outside NFSL – Moderate disturbance, 0-20 years old Within NFSL - Moderate disturbance, 20-30 years old Outside NFSL – Moderate disturbance, 0-20 years old High disturbance. 30-40 years old High disturbance, 20-30 years old Moderate disturbance, 0-20 years old Within NFSL Outside NFSL – Moderate disturbance, 0-20 years old Within NFSL Outside NFSL – High disturbance Natural or aggregate surface Paved road

Coefficient 0

High disturbance 0-20 years old

0.11 0.06 0.11 0 0.11 0.06 0.11 0.06 0.17 0.11 0 0.11 0.5 1.0 1.0 1.0 0.21

Assumes shrub and grass/forb communities within NFSL are recovered or in an undisturbed, natural condition. These vegetation types located outside NFSLs are assumed to be moderately disturbed. 1

2 Does not include some naturally barren ground. For analysis, assumes that 50% of land mapped as barren on NFSL is a result of mechanized treatment or is a disturbed condition. On lands outside NFSL, analysis assumes 100% disturbed.

For this analysis of current condition, it was assumed that lands outside the National Forest boundary were all disturbed in the last 20 years. This is a conservative assumption due to the lack of current data on privately owned lands.

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The approach used for this analysis of cumulative effects generally over-estimates disturbance levels and as such, is a conservative approach that would take a “worst case” look at watershed effects. An example is the stands mapped as being less than 60% canopy closure. These were assumed to be in this condition as a result of treatment, when if fact, many are naturally occurring. Cumulative effects analysis begins with past and present actions. Many of the past activities are accounted for in the vegetative mapping that was used (i.e. past timber harvest), as described by the current condition. Projects that have occurred since the mapping was completed or that are ongoing were accounted for in the analysis. Past actions, though not specifically listed by name, provide an opportunity to understand the current condition of the watersheds analyzed in this report. Map I-2 displays known past management actions by the decade in which they were implemented. Also see Table I-2 for the amount and types of treatment by decade. Other actions that have occurred on NFSL that are not shown on the map include fire suppression, road reconstruction and maintenance, recreation trail construction and reconstruction, ski area construction and expansion, and various salvage efforts of individual trees as well as roadside hazard tree removal. A major project that covered the majority of the Ashland Municipal Watershed was the Helikopter Salvage Sale that removed dead and dying ponderosa pine with a helicopter across the entire Ashland Creek sub-watershed in the 1980’s. Table I-2. Past Vegetation Management Within the Analysis Area Decade of Treatment Harvest Type 1950 1960 1980 1990 Unknown Clearcut 39 420 123 78 59 Partial Removal 106 Sanitation 72 Shelterwood 11 HHSP 16 Shaded Fuel Break 230 Total Acres 56 492 353 89 166

Total Acres 720 106 72 11 16 230 1,155

Present actions do not include actions that are considered unreasonable to predict, such as winter storm damage resulting in blowdown/snowdown, unforeseen large scale insect or disease outbreaks, and unforeseen large-scale wildfires, or other natural or human caused disasters. Based on analysis of past and present actions and the current condition, the following percent ERA values were determined for the sub-watershed analysis areas: Table I-3. Current Percent ERA by Watersheds Ashland Neil Upper Wagner Hamilton Total acres 15,785 13,563 5,875 4,127 ERA 465 1,090 316 1,249 Percent ERA 2.9% 8.0% 5.4% 30.3% Note: Even though the same satellite imagery was used, the values shown in the above table will not match exactly to the values in other analysis done in these sub-watersheds (Mt. Ashland Ski Area Expansion FEIS). This is due to a different configuration of the sub-watershed analysis areas.

The most noticeable value in Table I-2 is the high percent ERA value for the Hamilton Creek sub-watershed (30.3%). This is due to the amount of private land within the city limits of Ashland. Approximately 93% of this sub-watershed is off NFSL and has been highly developed and roaded. Not including private land, the percent ERA for the portion of the sub-watershed on National Forest is less than one percent. The land within the city limits, though developed and roaded, is in a static condition with storm drainage, etc. This model was not designed to evaluate these types of situations. FEIS APPENDIX I Cumulative Watershed Effects Analysis

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MAP I-2. Past Treatments by Decade

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Of the total area within this sub-watershed, only an estimated 35% is considered forested. Considering only forested land within the sub-watershed, the percent ERA would be 10.3%. It could be assumed that only the forested land has the ability to be managed so that is all that should be considered in the cumulative effects analysis. Due to the larger size of the Ashland Creek sub-watershed, the lands within the city limits do not influence the percent ERA value. Private lands have an influence on the percent ERA values for the Neil Creek and Upper Wagner Creek sub-watersheds. Threshold of Concern (TOC) The TOC is developed specifically for each watershed and is based on channel sensitivity (C), beneficial uses (B), soil erodibility (E), hydrologic response (H), and slope stability (S). The ERA Methodology contains detailed evaluation techniques that are described below to determine the numerical index for each of the factors. Once the index values have been determined for each watershed, the Watershed Sensitivity Level (WSL) is calculated using the following the equation: WSL = 3C + 2B + E + H + S. Next, the WSL is converted to a watershed specific TOC value based on the equation: TOC = (43 – WSL) / 2. The number “43” is used because it best fits a regression of the watershed sensitivity levels and previously determined TOCs on the Klamath NF which has similar conditions as the Upper Bear Analysis Area. Following is a discussion of each of the factors used to determine the TOC values for each of the sub-watershed analysis areas: Channel Sensitivity (C) This is based on Pfankuch stream stability ratings for the primary streams and major tributaries through each watershed. Since Pfankuck ratings are not available in most streams across the Forest, professional judgment is used in most cases. Generally, streams are considered moderately sensitive unless there are indications otherwise. Table I-4. Channel Sensitivity Rating Parameter Sensitivity Class Very High High Channel Moderate Sensitivity Low Very Low

Index 5 4 3 2 1

Pfankuch Rating >130 115-130 77-114 39-76 50% of the watershed Rain on snow zone 25-50% of the watershed Rain on snow zone < 25% of the watershed

Slope Stability (S) This factor is based on the inherent sensitivity of the watershed to landslides. The index is computed by running the landslide model on watersheds to arrive at a background (assuming no disturbance) landslide volume in cubic yards per acre per decade. Table I-8. Slope Stability Index Parameter Risk Class

Slope Stability

Index

Very High

5

High

4

Moderate

3

Low

2

Very Low

1

FEIS APPENDIX I Cumulative Watershed Effects Analysis

Stability Rating Greater than 3.2 cy/acre per decade Between 2.6 and 3.2 cy/acre per decade Between 2.0 and 2.6 cy/acre per decade Between 1.0 and 2.0 cy/acre per decade Less than 1.0 cy/acre per decade

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The following table displays the TOC values by sub-watershed analysis area that was used for this analysis: Table I-9. Threshold of Concern Values by Watershed

Watershed Ashland Neil Upper Wagner Hamilton

Beneficial Uses 5 4 4 3

Channel Stability 3 3 3 3

Soil Erodibility 2 2 2 2

Hydrologic Response 3 3 3 2

Slope Stability 2 2 2 2

Watershed Sensitivity Level 26 25 25 21

Threshold Of Concern 8.5 9.0 9.0 11.0

Risk Ratio The risk ratio is calculated by dividing ERA values by the TOC value. A Risk Ratio approaching or greater than 1.00 serves as a “yellow flag” indicator of increasing susceptibility for significant adverse cumulative effects occurring within a watershed. Susceptibility of cumulative watershed effects generally increases from low to high as the level of land disturbing activities increase toward a risk ratio value of 1.00 (USFS 1988). Watersheds with a “yellow flag” rating of 1.00 are not necessarily in eminent danger of unacceptable cumulative watershed effects, but these watersheds contain enough disturbance to “warrant a closer look” (USDA 1996). It should be noted that the ERA Methodology analyzes watershed conditions regardless of land ownership. The table below summarizes the risk ratio calculations by sub-watershed analysis area based on current conditions. These values are used as a baseline against which the alternatives area compared (i.e., NoAction). Table I-10. Current Condition Risk Ratio Calculations by Watershed Ashland Neil Upper Wagner Percent ERA 2.9% 8.0% 4.5% TOC 8.5 9.0 9.0 Risk Ratio 0.346 0.894 0.598

Hamilton 30.3% 11.0 2.751

The risk ratios for the Ashland Creek and Upper Wagner sub-watersheds are at levels that do not warrant concern at this time. The value for the Neil Creek sub-watershed approaches the 1.0 threshold, but is currently below. The Hamilton Creek sub-watershed has a value that exceeds 1.0 and indicates a potential for adverse cumulative effects. However, as previously discussed, approximately 93% of this sub-watershed is off NFSL and has been highly developed. Of the total area within this sub-watershed, only an estimated 35% is considered forested. Considering only forested land within the sub-watershed, the percent ERA would be 10.9%. Based on this assumption, the current condition risk ratio would be 0.932. Not including private land, the percent ERA for the portion of the sub-watershed on National Forest is less than one percent. The land within the city limits, though developed and roaded, is in a static condition with storm drainage, etc. Alternative Comparison Each of the Action Alternatives proposed under the FEIS were evaluated by calculating the change in ERA values that would be a result by implementing the each Action Alternative. Coefficients are used to model changes in vegetation or land cover. These coefficients were developed by specialists on the Klamath NF and have been updated as a result of monitoring and review of projects. Coefficients are additive, in other words the coefficients for prescriptions are added to logging system coefficients, which are added to site preparation coefficients. FEIS APPENDIX I Cumulative Watershed Effects Analysis

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Table I-11. ERA Project-Scale Coefficients Roads Prescription Miles 12 m (40 feet) High disturbance X wide prism, Moderate 4.77 slopes >35% disturbance Low disturbance None Miles 6 m (20 feet) X wide prism, 2.39 slopes