Ice Timber Sale and Fuels Reduction Project. Watershed. Specialist Report

Transcription

1 Ice Timber Sale and Fuels Reduction Project Watershed Specialist Report Christopher Stewart Hydrologist, Kern River Ranger District Sequoia National Forest November 17,

2 Introduction: This report documents watershed conditions of the Ice Timber Sale and Fuels Reduction project area. It contains information on the affected environment and effects of alternatives on watershed resources. Cumulative watershed effects of the treatments are quantified using the Regional Cumulative Watershed Effects (CWE) analysis modified by the Sequoia National Forest Mediated Settlement Agreement. A surveying and monitoring procedures section has been added to this report to aid the reader in understanding the procedures used to evaluate field conditions. A soils section has been added to this document to bring Ice project documents up to current standards and guidelines. This project proposes activities in tractor units only and fuel treatments. Helicopter units were completed in 2006 and have been included in cumlative effects analysis. Watershed Analysis Affected Environment: Soils Soils in the project area are mainly of granite origin and display signs of the classic decomposed granitics, which include low productivity with high erosion risk from sheetwash and dry ravel. These soils have low clay content and therefore resist compaction (Gomez et al. 2002). The other soil types are of metasedimentary origin. These soils have a finer texture and more fertility than the granitics. Table 1 displays the soil erosion hazard rating in acres by unit for the Ice Timber Sale and Fuels Reduction Project Project. Table 2 lists the soil types within the project area. Soil Erosion Hazard Rating (EHR) defininitions are included in appendix D. Table 1: Soil Erosion Hazard Rating (EHR) by unit Unit Number Soil Erosion Hazard Rating (Acres) Very High High Moderate Low Total Acres Misc Total

3 Map Unit Number Map Unit Name Auberry Cieneba Rock Outcrop Complex Chaix Rock Outcrop Chawanakee Complex Dome Chaix Rock Outcrop Association Dome Chaix Rock Outcrop Woolstalf Rock Outcrop Complex Woolstalf Rock Outcrop Complex % of Project Area 3.4% 44% Table 2: Ice Timber Sale and Fuels Reduction Project: Soils Characteristics Table Slope 30% - 50% 30% - 50% 8.1% 5% - 30% 9% 1.8% 33.7% 30% - 50% 10% - 30% 30% - 50% Soil Components Auberry: 45% Cieneba: 25% Rock outcrop: 15% Other: 15% Chaix: 45% Rock Outcrop: 30% Chawanakee: 15% Other: 10% Dome: 45% Chaix: 20% Rock Outcrop: 20% Other: 15% Dome: 35% Chaix: 30% Rock Outcrop: 20% Other: 15% Woolstalf: 50% Rock Outcrop: 20% Other: 30% Woolstalf: 50% Rock Outcrop: 30% Other: 20% Maximum EHR (Bare Ground) Moderate High Moderate Moderate Moderate High Runoff Rapid Rapid Rapid Rapid Medium to Rapid Rapid Soil Management Group III, Moderately Difficult III, Moderately Difficult II, Readily Manageable II, Readily Manageable II, Readily Manageable III, Moderately Difficult Soil Limiting Factors Shallow Soils Steep Slopes 30% Rock Outcrop Plant Competition Plant Competition Steep Slopes Plant Competition Steep Slopes 30% Rock Outcrop Plant Competition 3

4 Hydrology Ice Timber Sale and Fuel Reduction project could potentially increase sediment into nearby streams. In order to minimize the impact associated with increased sediment, the project will implement Best Management Practices (BMPs). Effectiveness monitoring for BMP implementation would follow BMP protocol. Stream Condition Inventory (SCI) would be used to establish baseline conditions of stream channels within the project area. Once the project is completed, the SCI site will be resurveyed to track any changes as a result of project implementation. There are four hydrologic unit code (HUC) 6 watersheds affected by the Ice Timber Sale and Fuels Reduction project. Table 3 displays characteristics of the four HUC 6 watersheds. Table 3: Attributes of the HUC 6 watersheds effected by the Ice Timber Sale and Fuels Reduction Project Forest HUC 6 # HUC 6 HUC 6 Watershed Stream Beneficial Uses (Existing) Acres Watershed # Class 09G Tillie Creek III Mun, Agr, Rec, Wild, Frsh 12,674 09H French Gulch Creek III Agr, Rec, Wild, Frsh 6,949 05C Cedar Creek I Agr, Rec, Cold, Wild, Spwn, Gwr, Frsh 2,414 Agr = Agriculture Mun = Municipal Spwn = Fish Spawning Cold = Coldwater Fishery Gwr = Groundwater Recharge Wild = Wildlife Wrm = Warmwater Fishery Frsh = Fresh Water Ind = Industrial Rec = Contact and/or Non-Contact Recreation Tables 4 through 6 display HUC 6 and HUC 7 subwatersheds and their associated river basins for the drainages associated with the project area. HUC 7 subwatersheds are defined by stream class in tables 4 through 6. Where Stream Stability Evaluation and Stream Condition Inventory (SCI) surveys have been done information has been provided. A full description of terms, Stream Condition Inventory (SCI) surveys, channels types, and channel stability ratings can be found in Appendix A. For more information dealing with threshold of concern comments see the cumulative effects section of this document. Tillie Creek (9G) The Tillie Creek 9G watershed is located west of the community of Wofford Heights. This watershed has been previously impacted by grazing, timber sales, forest service roads and trails, and unauthorized OHV routes. Also, this watershed is affected by the community of Alta Sierra and the Shirley Meadows Ski Area. The community and ski area have the greatest effect on HUC 7 9GB, 9GC, and 9GD watersheds. The community and the ski area contribute more uninhibited runoff resulting in a greater potential for sediment to the creek. An SCI site is located on Ice House creek below Alta Sierra to monitor this watershed. Table 4 displays HUC 6 4

5 and HUC 7 subwatersheds and their associated river basins for the drainages associated with the project area. HUC 7 subwatersheds are defined by stream class. Table 4: Tillie Creek Subwatersheds and Associated Stream Classes Basin Basin # Subwatershed Subwatershed # Stream Class Tillie 9G North Fork Ice House Creek 9GA IV Ice House Creek 9GB III Shirley Creek 9GC III Tillie Creek 9GD IV Rattlesnake Creek 9GE IV Cane Creek 9GF IV Lower Ice House Creek 9GJ III Southern Trib. to Ice House Creek 9GK III Tillie Creek Basin stream surveys indicate the riparian ecotypes are 50% naturally unstable and 50% naturally stable. Shirley Creek subwatershed (9GC) contains a naturally unstable A3a channel type and a naturally stable A1a channel type. The A1a reach is closely downstream from the A3a. The Southern Trib. to Ice House Creek subwatershed (9GK) contains one A5 naturally unstable stream. This reach is located within private property. The other naturally stable A1 stream is located in the Shirley Creek subwatershed (9GJ). Riparian ecotype level of impact is high for the naturally unstable and minimum for the naturally stable reaches. A SCI plot was established on Ice House Creek. Figure 1 illustrates a cross section of the creek and Figure 2 shows the particle distribution. 5

6 Figure 1 Cross section of Ice House Creek Figure 2 Particle distribution of Ice House Creek Ice House Creek is a stable sensitive, low impact, gravel dominated, low gradient, B4 channel. Ice House Creek has a well defined bankfull feature and floodplain, which suggests that it is a stable and hydrologically functioning system. This drainage yielded a Pfankuch stability rating of good. Average shading along the stream channel is 97 percent. French Gulch (9H) The French Gulch 9H watershed is located west of Lake Isabella. This watershed has been previously impacted by grazing, timber sales, forest service roads and trails, and unauthorized routes. All HUC 7 watersheds are within threshold. Table 5 displays HUC 6 and HUC 7 subwatersheds and their associated river basins for the drainages associated with the project area. HUC 7 subwatersheds are defined by stream class. Table 5: French Gulch Creek Subwatersheds and Associated Stream Classes Basin Basin # Subwatershed Subwatershed # Stream Class French Gulch 9H Woodward Creek 9HA III Stable Creek 9HE III Cedar Creek (5C) The Cedar Creek watershed 5C begins in the western part of the Greenhorn Mountains and flows west toward the community of Glennville. Past impacts in this watershed include grazing, forest service roads and trails, State Highway 155, past timber sales, unauthorized routes, and the community of Alta Sierra. The community has the greatest effect on the HUC 7 5CK 6

7 watershed. The community does contribute more uninhibited runoff resulting in a greater potential for sediment to the creek. Three SCI sites are located on Cedar Creek to monitor this watershed. Table 6 displays HUC 6 and HUC 7 subwatersheds and their associated river basins for the drainages associated with the project area. HUC 7 subwatersheds are defined by stream class. Table 6: Cedar Creek Subwatersheds and Associated Stream Classes Basin Basin # Subwatershed Subwatershed # Stream Class Cedar 5C Upper Alder Creek 5CC III Trib. to Alder Creek 5CD III Lower Slick Rock Creek 5CE III Upper Bear Creek 5CG III The westernmost part of Cedar Creek Basin contains an SCI site. The surveyed reach is located near Alder Campground. The reach extends 250 meters, starting above the tributary to Alder Creek. Figure 3 illustrates a cross section of the creek and Figure 4 shows the particle distribution. Figure 3 Cross section of Cedar Creek at Alder Creek Campground Figure 4 Particle distribution of Cedar Creek at Alder Creek Campground Shading from riparian vegetation surrounding the stream has slightly increased. From the 2006 surveys, the average cover is 80.3%. The Pfankuch stream stability evaluation yielded fair rating. Alder Creek has a well defined bankfull feature and floodplain, which suggests a stable and hydrologically functioning system. These conditions are stable even with additional impacts 7

8 produced by the campground, bridge, and road. SCI data analysis supports a hydrologically functioning system. Subwatershed 5CB has an SCI site located below Cedar Creek Campground and state highway 155. The 2006 survey of Cedar Creek identifies the reach as a B4a channel type with a Pfankuch stream stability rating of fair. Recovery potential for an impacted (impact level of high to extreme) B4a channel type is good. No instability concerns were seen in The average cover provided by the riparian and surrounding habitat is 87.5%. The stream appears to be hydrologically functioning. Figure 5 illustrates a cross section of the creek and Figure 6 shows the particle distribution. Figure 5 Cross section of Cedar Creek at Cedar Creek Campground Figure 6 Particle distribution of Cedar Creek at Cedar Creek Campground Stream surveys in the Alder Creek subwatersheds are comprised of 60% naturally-stable, A1a, A2a, and B1 channel types of bedrock and boulder controlled reaches. These reaches have a minimal to moderate impact rating. The other 40% of the stream reaches are steep, finegrained, naturally unstable, A4a and A3 reaches. These have impact ratings of minimal. Of the reaches surveyed about 49% have sediment levels high enough to impact fish habitat. The source of this sediment is road 25S04, dispersed camping adjacent to Alder Creek, and the Alder Creek Campground. Riparian vegetation and bank stability conditions are similar to Cedar Creek. 8

9 Bear Creek is classified as a naturally-stable channel comprised of bedrock and boulder substrate for 60% of the reaches surveyed. All naturally-stable A1a channel types display minimal evidence of impact. Channel features of an A4 naturally-unstable (landslide prone) channel type with a fine-grained substrate, and steep channel gradient; occur along 16% of the surveyed reaches. The naturally-unstable channel type also exhibits minimal impacts. Sixteen percent of Bear Creek is classified as a B4 stable-sensitive channel type. The stable-sensitive reach, which drains about 11 acres, shows a low level of impact. The low impact ratings in Bear Creek reflect high sediment in the channel bottom. The sedimentation source is road 25S04. Grazing contributes a small percentage of the sediment to the creek. Private land upstream also contributes to channel sedimentation. The Upper Bear Creek subwatershed (5CG) contains an SCI surveyed reach. The SCI reach extends about 39 meters. The site was first surveyed in 2001 and resurveyed again in Shading has increased from an average of 77.5% to 80% cover, providing more shade for aquatic species. Pfankuch rates this stream as fair. Figure and 2006 Cross section of Bear Creek Figure and 2006 Particle distribution of Bear Creek Figure 7, cross section 3 shows a loss of 0.03 square meters in the channel bed materials over five years. Cross sections 1 and 2 were also resurveyed, but their monumented cross section pins were missing. Therefore data analysis could not be completed. Results from the remaining cross section 3 indicate the site has not significantly changed. 9

10 The particle distribution in figure 8 shows a shift right indicating coarser materials in the channel bed suggesting finer sediments were transported out of the system. This shift has not affected the channel type which remains a B5a. The amount of bed material lost over the past five years is insignificant, and geomorphology of the stream or has not been affected. As a result instability is not an issue within this reach. The SCI data analysis supports a hydrologically functioning channel within the range of natural variability. Environmental Consequences: Alternative A - No Action The no action alternative would not create additional impacts by management activities to the watersheds within the project area. The alternative would allow the watersheds to continue recovering from previous management activities. The CWE model outputs are displayed in Table 7. Twelve of the fourteen subwatersheds in the analysis area are at low to moderate levels of TOC, ranging from 16% to 51% of threshold. Ice House Creek (watershed 9GB) is currently at 122% of threshold and Shirley Creek (watershed 9GC) is currently at 92% of threshold. This is due mainly the urban development in the Alta Sierra community as it accounts for approximately 30 ERAs, which is the TOC for the watersheds. The lack of management activities would allow the recovery of the watershed from previous management activities to proceed at its present rate. However, the No Action alternative could increase the potential for adverse long-term effects to the subwatersheds within the project area from a large wildfire, as no fuel reduction activities would occur. Large burned areas can contribute large amounts of additional sediment into streams if the fires are intense and remove all or most of the vegetation. Effects Common to all Action Alternatives (Alternatives B and C) Management activities would add to the sediment already entering the system from natural erosion and other management activities. Additional sediment generated by these activities can enter the stream systems from road reconstruction or from overland flow of sediment from fuels reduction activities. Fuels would be reduced in all of the action alternatives, thus decreasing the potential of a catastrophic wildfire occurring in the analysis area. While controlled burns would have a shortterm detrimental effect to the watershed basin, there would be long-term beneficial effects. 10

11 Unlike a large, intense wildfire, a light controlled burn leaves a mosaic of ground cover in the burn area. Controlled burns do not consume more than 50% ground cover on average, so sediment movement from the controlled fires is limited to acceptable levels. The prescribed underburning would reduce the risk of a catastrophic fire in the riparian zones, which could create excessive damage to the riparian zones. The soils in the project area are not of the textural class typically prone to compaction. Care would be taken in the soil units with the higher Erosion Hazard Ratings (EHRs) to implement Best Management Practices (BMPs) properly and retain large woody debris (LWD) to increase soil productivity and stability. These areas also include some steeper ground in the project area. Mechanical access into units would be limited to slopes less than 35%. This would mitigate potential increases in erosion from these areas. The implementation of BMPs would make it possible to implement this project while enhancing soil organic material, increasing LWD, minimizing soil disturbance, and preventing accelerated erosion. Therefore, the Ice Timber Sale and Fuels Reduction Project would be consistent with soil quality standards (Appendix E). Alternative B - Proposed Action Alternative B would disturb the greatest amount of ground, and have the greatest potential to affect the stream channels by generating the most additional sedimentation to streams. Table 7 shows the percent of TOC for each subwatershed where management activities are proposed. Following implementation of the activities proposed in Alternative B, the Shirley Creek watershed is estimated to be at % of the TOC. The field review of this stream found that the creek is in a high fair condition and that the high bedrock content of the streambed helps stabilize and protect the stream. This subwatershed is located directly below the Alta Sierra community, which makes it a strategic area for completing fuels reduction to protect the community. This area has also been identified as having some of the heaviest fuel loadings in the analysis area. Implementation of fuels reduction to reduce the risk of catastrophic fire is important to the protection of the long-term health of the watershed. 9GB/9GC-Ice House/Shirley Creek - Extreme The Ice House Creek subwatershed (9GB) is at 122% of TOC under the proposed action. The proposed action proposes underburning approximately 128 acres within the watershed for reduction of surface fuels. This would cause a short term increase of less than 1% in the TOC. This small short term increase in ERAs is considered acceptable because of the need to treat 11

12 fuels to reduce the high fire risk in this area, which poses a threat to human life and property and a long term risk of a much larger effect to the watershed in a wildfire event. The Shirley Creek watershed (9GC) is estimated to be at approximately 100% of TOC under the proposed action. This subwatershed includes fuel treatment units. The ERAs produced from fuels treatments account for most of the increased ERAs over the no action alternative. Burning under controlled conditions is considered to have a short term impact on watershed health, due to the rapid regeneration of vegetation following burning. Reduction of the continuity of the ladder fuels is considered to be one of the most important measures to reducing the risk of a catastrophic fire in the Wofford Heights and Alta Sierra communities. Reduction of the risk of catastrophic fire is also important to the long term health of this subwatershed, as a hot wildfire that removed all of the vegetation in this steep area would likely lead to very high erosion rates. The remaining 12 subwatershed are estimated to be at low to moderate TOC levels following the proposed management activities, ranging from 20% to 53% of TOC. Based on the CWE analysis of Alternative B, the chances of cumulative watershed effects occurring within the Revised Ice Analysis Area or downstream as a result of the proposed management activities should be minimal when BMP's, Riparian Standards and Guidelines, Project Design Features, and Forest Plan Standards and Guideline are applied. Of the action alternatives, Alternative B contributes the greatest amount to creating forest conditions conducive to limiting the size and severity of wildfires within the analysis area. Alternative B therefore does the greatest amount to reduce the potential for long term watershed impacts that would result from a wildfire in the area. Alternative B would implement the remaining road reconstruction on 5 miles of road. Watershed health would be improved in the long term by reducing the amount of sediment entering the streams through road improvements. Sale area improvement funds would be generated that could be used to help finance the watershed improvement needs identified in the analysis area. Alternative C Modified Proposed Action This alternative has the least amount of ground disturbance of the action alternatives and is therefore expected to have the least amount of short term impact to the watershed basin of all the action alternatives. The additional sediment into the streams would probably show up as more deposition in pools and gravel areas would have more sand in them. This alternative is not expected to impact beneficial uses. 12

13 Table 7 shows the percent of TOC for each subwatershed where management activities are proposed. The effects to the Ice House Creek and Lower Shirley Creek watershed were covered in the Alternative B section. The remaining 12 subwatersheds are estimated to be at low to moderate TOC levels following the proposed management activities, ranging from 17% to 50% of TOC. Based on the CWE analysis of Alternative C, the chances of cumulative watershed effects occurring within the Revised Ice analysis area or downstream as a result of the project should be minimal when BMP's, Riparian Standards and Guidelines, project design features and Forest Plan Standards and Guidelines are applied. Of the action alternatives, Alternative C contributes the least amount to creating forest conditions conducive to limiting the size and severity of wildfires within the analysis area. Alternative C therefore does the least amount to reduce the potential for long term watershed impacts that would result from a wildfire in the area. There would be no improvement to watershed health through road reconstruction activities in this alternative. No sale area improvement funds would be generated to help offset the costs of watershed improvement needs identified in the project area. Cumulative Effects Analysis for All Action Alternatives Table 7 displays the CWE analysis for the project area. Percent Threshold of Concern (%TOC) for alternatives A, B, and C for the years 2010 through 2012 are the focus of the analysis. Small short term increases in %TOC is considered acceptable because of the need to treat fuels to reduce the high fire risk in this area, which poses a threat to human life and property and a long term risk of a much larger effect to the watershed in a wildfire event. Treatments would use existing landings so to utilize previously compacted sites, skid trail patterns would be designed to minimize soil disturbance and compaction. Proper drainage on these features would reduce the potential for water concentration and runoff. Water barring and slashing of skid trails and landings would reduce the potential for sedimentation and erosion. Treatment debris in the form of slash and whole trees along the contour would reduce the potential for CWE. 13

14 Table 7: CWE Results by HUC 7 Watershed. Watersheds with *values indicate current conditions or alternatives that place the watershed over threshold and at extreme potential for CWE. Watershed 5CC Name 2010 %TOC 2011 %TOC 2012 %TOC Acres Alt A Alt B Alt C Alt A Alt B Alt C Alt A Alt B Alt C Upper Alder Ck 5CD Alder trib CE L. Slick Rock Ck 1, CG Upper Bear Ck GA N. Ice House Ck GB Ice House Ck * * * * * * * * * 9GC Shirley Ck * GD Tillie Ck GE Rattlesnake Ck GF Cane Ck 2, GJ Shirley Ck 1, GK S.Tr. Ice House Ck HA Woodward Ck 1, HE Stable Ck Management Requirements and Constraints: Best Management Practices Forest management and associated road building in the steep rugged terrain of forested mountains has long been recognized as sources of non-point water quality pollution. Non-point pollution is not, by definition, controllable through conventional treatment plant means. Nonpoint pollution is controlled by containing the pollutant at its source, thereby precluding delivery to surface water. Sections 208 and 319 of the Federal Clean Water Act, as amended, acknowledge land treatment measures as being an effective means of controlling non-point sources of water pollution and emphasize their development. Working cooperatively with the California State Water Quality Control Board, the Forest Service developed and documented non-point pollution control measures applicable to National Forest System lands. These measures were termed "Best Management Practices" (BMPs). BMP control measures are designed to accommodate site specific conditions. They are tailor-made to account for the complexity and physical and biological variability of the natural environment. The implementation of BMP is the performance standard against which the success of the Forest Service s non-point pollution water quality management efforts is judged. 14

15 The Clean Water Act provided the initial test of effectiveness of the Forest Service non-point pollution control measures where it required the evaluation of the practices by the regulatory agencies (State Board and EPA) and the certification and approval of the practices as the "BEST" measures for control. Another test of BMP effectiveness is the capability to custom fit them to a site-specific condition where non-point pollution potential exists. The Forest Service BMPs are flexible in that they are tailor-made to account for diverse combinations of physical and biological environmental circumstances. A final test of the effectiveness of the Forest Service BMP is their demonstrated ability to protect the beneficial uses of the surface waters in the State. Best Management Practices, as described in this document have been effective in protecting beneficial uses within the affected watersheds. These practices have been applied in other projects within the Sequoia National Forest. Where proper implementation has occurred there have not been any substantive adverse impacts to cold water fisheries habitat conditions or primary contact recreation (etc.) use of the surface waters. The practices specified herein are expected to be equally effective in maintaining the identified beneficial uses. Stream condition inventory (SCI) plots have been established at Cedar Creek at Alder Creek Campground, Cedar Creek and Cedar Creek Campground, Cow Creek, and Bear Creek to monitor the effectiveness of the prescribed BMPs. The following management requirements are designed to address the watershed management concerns. Most are BMPs from the Forest Service publication "Water Quality Management for National Forest System Lands in California" (USDA Forest Service, 2000). All applicable water quality BMPs shall be implemented. The implementation phase of the BMPs occur after a project is completed, but before the winter season. BMP monitoring of the project is done one year later after the project has experiences one rainy season. A list of BMPs used within the Ice Timber Sale and Fuels Reduction Project is as follows along with a brief summary of what each entails: Timber 1.1 Planning Process The objective of this practice is to incorporate water quality and hydrologic consideration into the panning process. This document constitutes the incorporation of water quality and hydrologic consideration into the planning process. 15

16 1.2 Unit Design The objective of this practice is to ensure that unit design would secure favorable conditions of water quality and quantity while maintaining desirable stream channel characteristics and watershed conditions. The design of the units for the Ice Timber Sale and Fuels Reduction Project includes the size and distribution of natural structures as a means of preventing erosion and sedimentation. Other water quality considerations include routes used by mechanical equipment would not occur on slopes greater than 35%, and defining designated routes and crossings for drainages. 1.3 Surface Erosion Hazard Determination for Unit Design The objective of this BMP is to identify high erosion hazard areas in order to adjust treatment measures to prevent downstream water quality degradation. Lop and scatter of slash on treated units where appropriate would serve to reduce erosion hazard ratings and reduce the potential for erosion. Table 8 displays the soil erosion hazard rating in acres by unit for the Ice Timber Sale and Fuels Reduction Project. Table 8: Acres of Very High, High, Moderate, and Low soil erosion hazard rating by unit Unit Number Soil Erosion Hazard Rating (Acres) Very High High Moderate Low Total Acres Misc Total

17 1.4 Use of Area Maps and /or Project Maps for Designating Water Quality Protection Needs. The objective of this practice is to ensure recognition and protection of areas related to water quality protection delineation on project maps. All stream courses in the project area have been mapped and are displayed on figure 9, the project area map. These streamcourses are to be protected under C.6.5 of the timber sale contract. Additionally any other stream courses or wet areas not identified on the sale area map and identified during operation are to be protected under C6.5 of the timber sale contract. Figure 9: Stream Courses in the Ice Timber Sale and Fuels Reduction Project Area 17

18 1.5 Limiting Operating Period of Timber Sale Activities The objective of this practice is to ensure that site preparation contractors conduct their operations, including, erosion control work, road work, maintenance, and so forth, in a timely manner, within the time specified in the Contract. Operations should be scheduled and conducted to minimize erosion and sedimentation when ground conditions are such that excessive rutting and soil compaction would not occur. Normal operating periods from June 1 to November 15 are identified for this project. Operations could be authorized pending field verification of ground conditions. Soil moisture conditions need to be appropriate for operations. This would reduce the effects of wet conditions on operations. 1.8, 1.19 Streamside Management Zone Designation, Streamcourse and Aquatic Protection The objectives of these measures are to designate a zone along riparian areas, streams, and wetlands that would minimize potential for adverse effects from adjacent management activities. Management activity in these zones is designated to improve riparian values. Additionally, objectives of SMZ s are to conduct management actions within these areas in a manner that maintains or improves riparian and aquatic values. Provides for unobstructed passage of stormflows, controls sediment and other pollutants from entering streamcourses, and restores the natural course of any stream as soon as practicable, where diversion of the stream has resulted from timber management activities. It is expected that development of RCA s (Riparian Conservation Areas) are included under these two BMPs. The purpose of RCA s are to protect riparian and aquatic ecosystems and the dependent natural resources associated with them during site-specific project planning and implementation 1. Forest strategy provides direction to maintain or improve conditions for riparian dependent resources. RCA s include aquatic and terrestrial ecosystems and lands adjacent to perennial, intermittent, and ephemeral streams, as well as around meadows.riparian dependent resources are those natural resources that owe their existence to the presence of surface or groundwater Forest Strategy also maintains or restores soil properties and productivity to ensure ecosystem health, soil hydrologic function and biological buffering capacity 2. SMZ should not be considered replacement of RCA s but a nested zone contained in the RCA developed for the filtering capability of the streamside zone. All streamcourses would be protected and assigned SMZ s. The streamcourses mapped on the Project Area Map provides information for development of watercourse protection maps. 1 Sierra Nevada Forest Plan Amendment ROD, 2004, page 42 2 Sierra Nevada Forest Plan Amendment ROD, 2004, page

19 Skid trail patterns would be designed in a manner to keep routes away from the drainages and cross drainages at designated locations. Any material that would cause obstruction of stormflows would be removed. All channels have SMZ s which are equipment exclusion zones. Ephemerals would have a minimum SMZ s of 25 feet based on field investigations. Table 9 below provides a summary of SMZ by Stream Class. Table 9: Streamside Management Zones (SMZ) widths by Stream Class Stream SMZ Width by % Slope Stream Class <30% >30% >40% >50% >70% Order Meadows 100 N/A N/A N/A N/A - Seeps Springs 100 N/A N/A N/A N/A - Bogs I times 4+ II the 3-4 III distance 2-3 IV < 50 < to slope 1-2 IV < 50 < 50 < 50 < 50 break 1-0 Within riparian conservation areas (RCAs) reduce as much as possible ground disturbing impacts (i.e., soil compaction, vegetation disturbance, etc.). BMPEP form T01 would be utilized to evaluate implementation on those units with SMZ s and other aquatic protection. Riparian Conservation Objectives provide direction for the RCA s and prescribe widths of 300 feet either side for perennial streams, 150 feet for seasonally flowing streams, and 150 feet for special aquatic features. Within this area all standards and guidelines for RCA s need to be meet. This area is a zone of closely managed activities and not a zone of equipment exclusion like SMZ s. 1.9 Determining Tractor Loggable Ground The objective of this practice is to minimize erosion and sedimentation resulting from ground disturbance of tractor logging systems. Determination of tractor loggable ground considers the physical site such as steepness of slopes and soil properties. 19

20 All tractor units would be conducted on slopes that do not exceed 35 %. Both office evaluations of slope using DEM s and field investigations of sites to verify slope percentages have been performed. All site preparation units identified for mastication meet slope requirements Tractor Skidding Design The objective of this practice is to design skidding patterns to best fit the terrain, the volume, velocity, concentration and direction of runoff water can be controlled in a manner that would minimize erosion and sedimentation. Skidding would not occur in SMZ s. Skidding would occur on stable slopes not greater than 35 %. Skidding would not occur down draws. Evidence of ruts associated or resulting from skidding pattern/path would be water-bared and if ground cover disturbance was reduced to amounts less than preexisting levels, these areas would be slashed through lop and scatter to 18 inches or chips from the mastication process. Rutting is characterized by the sunken tracks or grooves usually made when the ground is wet or soft. Ruts for the purposes of this analysis, are at least 2 inches in depth. BMPEP form T02 would be utilized to evaluate implementation on those units where mastication/site prep would occur. 1.13, 1.17 Erosion Prevention and Control Measures During Sale Operations, Erosion Control on Skid Trails, and Fuels Treatments The objective of these practices is to ensure that the purchasers operation would be conducted reasonably to minimize soil erosion. Any evidence of ruts associated or resulting from skidding pattern/path would be water-bared and if ground cover disturbance was reduce to amounts less than preexisting levels would be slashed through lop and scatter to 18 inches. Ruts for the purposes of this analysis, are at least 2 inches in depth. Skidding would occur on ridge tops and not within draws. Standard road maintenance practices would be implemented. BMPEP form T02 and T05 would be utilized to evaluate implementation on those units where skidding operations and where erosion prevention and control measures are expected to occur. 20

21 Erosion control measures would be implemented on all skid routes, landings, and temporary roads. Erosion control measures must include, but are not limited to, cross ditches (water bars), organic mulch, and ripping. Cross drains must be spaced according to the table 10, maintained in a functioning condition, and placed in locations where drainage would naturally occur (i.e., swales). Table 10: Cross Drain Requirements Spacing by Erosion Hazard Rating (Feet) % Slope Low Medium High Very High > Roads 2.3 Timing of Construction Activities This practice is to minimize erosion by conducting operations during minimal runoff periods. Operations should be scheduled and conducted to minimize erosion and sedimentation when ground conditions are such that excessive rutting and soil compaction would not occur. Roads would be maintained when conditions are dry. Erosion conditions would be kept as current as practicable on active road maintenance projects. 2.7 Control of Road Drainage The objective of this practice is to minimize the erosive effects of water concentrated by road drainage features; to disperse runoff form disturbances within the road clearing limits; to lessen the sediment yield from disturbances within the roaded areas; to minimize erosion of the road prism by runoff from road surfaces and uphill areas. Standard road maintenance practices would be implemented to meet the above objectives. 21

22 2.11 Control of Sidecast Material during Construction and Maintenance The objective of this practice is to minimize sediment production originating from sidecast material during roadway maintenance. Maintenance on those roads utilized by the project would not create sidecast materials onto the side of the road. All materials would either be consolidated onto the roadbed or moved to a stable location. BMPEP form E11 would be utilized to evaluate implementation on roads constructed, reconstructed or maintained during the project Servicing and Refueling of Equipment The objective of this practice is to prevent pollutants such as fuels, lubricants, bitumens and other harmful materials from being discharged into or near rivers, streams and impoundments, or into natural or man-made channels. Service and refueling locations would be located in landings. The forest would have a spill plan if the volume of fuel on site exceeds 660 gallons in a single container or a total storage at the site exceeds 1,320 gallons. It is not expected that any sites would exceed 660 gallons. Servicing and refueling would take place along landings or roads and follow forest spill plan direction. BMPEP form E12 would be utilized to evaluate implementation on those areas that meet the requirements for servicing and refueling of equipment Control of Construction and Maintenance Activities Adjacent to SMZ s The objective of this practice relative to this project is to protect water quality by controlling maintenance actions within and adjacent to any streamside management zone so that the following SMZ functions are not impaired: Acting as an effective filter for sediment generated by erosion form bare surfaces, dust drift, and oil traces; Maintain riparian habitat and channel stabilizing effects; Keep floodplain surface in a resistant, undisturbed condition to slow water velocities and limit erosion by flood flows. See Table 9 for SMZ widths by stream class. 22

23 2.21 Water Source Development consistent with Water Quality Protection The objective of this practice is to supply water for roads and fire protection while maintaining existing water quality. Locations identified for water drafting include Cedar Creek at Cedar Creek Campground (T25S, R32E, Section 18, MDBM) and one mile north of Tiger Flat on forest road 24S15 (T25S, R32E, Section 5, MDBM). BMPEP form E16 would be utilized to evaluate implementation on those areas identified for water source development Road Surface Treatment to Prevent Loss of Materials The objective of this practice is to minimize the erosion of road surface materials and consequently reduce the likelihood of sediment production from those areas. Dust abatement would occur on all roads associated with the project. Dust abatement in the Ice area would be completed by spraying water on the roads Traffic Control During Wet Periods The objective of this BMP is to reduce road surface disturbance and rutting or roads and to minimize sediment washing from disturbed road surfaces. To meet this BMP heavy equipment operation would be limited until soil has dried in the top 12 inches. Operations would be shut down during wet weather and not opened until conditions are dry enough to prevent damage to road resources and water quality. Fire 6.2 and 6.3 Consideration of Water Quality in Formulating Fire Prescriptions and Protection of Water Quality from Prescribed Burning Effects The objective of these practices is to provide for water quality protection while achieving the management objectives through the use of prescribed fire and maintain soil productivity, minimize erosion, ash, sediment, nutrients and debris from entering water bodies. Burn Piles would be placed a minimum of 20 feet from SMZ s and cross stream perpendicular to drainage flow; all handlines would be water barred; and ground cover maintenance would be maintained at 50% existing levels. BMPEP form F25 would be utilized to evaluate implementation on those areas that are treated with the use of prescribed fire. 23

24 Watershed Management 7.8 Cumulative Watershed Effects The objective of this practice is to protect the identified beneficial uses of water from the combined effects of multiple management activities when individually may not create unacceptable effects but collectively may result in degraded water quality conditions. The areas of concern relative to cumulative watershed effects associated with this project would include increases in runoff as a result of diminished ground cover and organic matter, increased fines and ash, and decreased soil roughness due to the timber and fuels activities. The increases in sediment and water yields could cause increases in erosion and sedimentation to stream courses. The project has been designed with practices in place to address these potential concerns. These practices would reduce the potential for cumulative watershed effects. Landings and temporary roads would utilize previously compacted sites, reducing the potential to increase compaction from current levels. Landings and temporary roads could be slashed and/or chipped and would be properly drained and would not be expected to add to increased runoff and associated sedimentation above current levels. Erosion has the potential to occur from concentrated water in any fire line, skid pattern or path created during operations. Water barring and slashing trails where these effects are seen would eliminate this effect. Landings would be drained and slashed to reduce the potential for water concentration and erosion. A 30% ground cover requirement for skid trails and landings would be expected after operations occur. This would require that at least 30% organic material would be left on these sites and no more than 70% bare ground could be seen. Past and present activities within the analysis area include wildfire and wildfire suppression, prescribed burning, timber harvest, road construction and reconstruction, road maintenance, large storm flow events, trail construction and maintenance, recreation use, residential development, and private land uses. Future management activities in the project area include the continuation of trail maintenance and road maintenance. Potential future management activities may include timber management and fuel reduction projects. However, site-specific information (e.g. location, dates, affected area, etc.) is not available for these potential future activities. If additional activities are proposed within the project area in the future, those activities would be fully analyzed as part of the planning process. Cumulative Watershed Effects (CWE's) The Sequoia National Forest uses a model to evaluate the CWEs of past, present, and reasonably foreseeable future management activities. The model evaluates cumulative watershed impacts produced by various management activities and determines the potential risk of cumulative watershed damage. CWE terminology is defined below. 24

25 CWEs include any change that involve watershed processes and are influenced by land management activities (Reid, 1993). CWE's accumulate in time and space. The National Environmental Policy Act of 1969 (40 CFR ) defines a CWE of a project as: The "cumulative impact" is the impact on the environment that results from the incremental impact of the action when added to other past, present, and reasonably foreseeable future actions regardless of what agency (Federal or Non-Federal) or person undertakes such actions. Cumulative impacts can result from individually minor but collectively significant actions taking place over a period of time. Assumptions, limitations, and data requirements of the Region 5 CWE direction are discussed fully in Region 5, FSH , Chapter 20. The Sequoia National Forest CWE model has modified this direction to include agreements made in the 1990 Mediated Settlement Agreement. The CWE analysis quantifies impacts by calculating the number of Equivalent Roaded Acres (ERAs) available for management activities within a subwatershed. An ERA is equivalent to one acre of land that is completely roaded. The disturbance level of each management activity is quantified by determining the number of ERA s that would produce an equal impact. The CWE methodology determines the percentage of threshold of concern (%of TOC). A low % of TOC value (50% or less) indicates a low risk of CWE s occurring as a result of the management activity. A high % of TOC value (80% or greater) indicates a high risk of a CWE occurring as a result of the management activity. A low % of TOC value does not imply that a CWE will not occur; it simply indicates a low risk of CWEs occurring. A % of TOC value of 80% or greater does not imply that a subwatershed is already over threshold or that CWEs will definitely occur, it only indicates that there is a high risk of CWEs occurring. Appendix B provides additional explanation of the Sequoia CWE methodology and is a summary of the Sequoia National Forest Cumulative Watershed Effects Field Guide (Kaplan-Henry & Machado, 1991). Until recently the CWE model assigned a recovery rate of 30 years for both vegetative and fire recovery. The Mediated Settlement Agreement directed the Forest to use this recovery rate until such time there was sufficient data to establish recovery rates based on references or onsite inventories to support a different rate. Dr. Neil Berg has provided inventories of past burns and fuels management activity to substantiate recovery rates for fire at 5 years (Bergs, 2007). Appendix C. 25

26 CWE Results Table 11 displays the CWE analysis for the project area. Percent Threshold of Concern (%TOC) for the No Action and Proposed Action alternatives for the years 2010 through 2012 are the focus of the analysis. Small short term increases in %TOC is considered acceptable because of the need to treat fuels to reduce the high fire risk in this area, which poses a threat to human life and property and a long term risk of a much larger effect to the watershed in a wildfire event. Treatments would use existing landings so to utilize previously compacted sites, skid trail patterns would be designed to minimize soil disturbance and compaction. Proper drainage on these features would reduce the potential for water concentration and runoff. Water barring and slashing of skid trails and landings would reduce the potential for sedimentation and erosion. Treatment debris in the form of slash and whole trees along the contour would reduce the potential for CWE. Table 11: CWE Results by HUC 7 Watershed. Watersheds with *values indicate current conditions or alternatives that place the watershed over threshold and at extreme potential for CWE. Watershed Name Acres 2010 %TOC 2011 %TOC 2012 %TOC Alt A Alt B Alt C Alt A Alt B Alt C Alt A Alt B Alt C 5CC Upper Alder Ck 5CD Alder trib CE L. Slick Rock Ck 1, CG Upper Bear Ck 9GA N. Ice House Ck GB Ice House Ck * * * * * * * * * 9GC Shirley Ck * GD Tillie Ck GE Rattlesnake Ck GF Cane Ck 2, GJ Shirley Ck 1, GK S.Tr. Ice House Ck HA Woodward Ck 1, HE Stable Ck The following discussion provides information regarding those watersheds with extreme potential for CWE. The subwatersheds of highest concern are those that are currently over threshold (>100% TOC used). These watersheds have the highest potential for CWE. 26

27 Subwatersheds Currently over Threshold with Extreme Potential for CWE The following watersheds have an extreme potential for CWE. These watersheds currently exceed or are at threshold. Both of these watersheds exceed TOC for the current condition. A subwatershed with TOC used > 100% has an extreme potential for CWE to occur. Selection of any alternative that includes watersheds over threshold would be expected to include mitigation to reduce this potential. Mitigation could include improvement of drainage structures, revegetation of disturbed sites, and special erosion control measures. 9GB/9GC-Ice House/Shirley Creek - Extreme The Ice House Creek subwatershed (9GB) is at 122% of TOC under the proposed action (Alternative B). The proposed action proposes underburning approximately 128 acres within the watershed for reduction of surface fuels. This would cause a short term increase of less than 1% in the TOC. This small short term increase in ERAs is considered acceptable because of the need to treat fuels to reduce the high fire risk in this area, which poses a threat to human life and property and a long term risk of a much larger effect to the watershed in a wildfire event. The Shirley Creek watershed (9GC) is estimated to be at approximately 100% of TOC under the proposed action. This subwatershed includes fuel treatment units. The ERAs produced from fuels treatments account for most of the increased ERAs over the no action alternative. Burning under controlled conditions is considered to have a short term impact on watershed health, due to the rapid regeneration of vegetation following burning. Reduction of the continuity of the ladder fuels is considered to be one of the most important measures to reducing the risk of a catastrophic fire in the Wofford Heights and Alta Sierra communities. Reduction of the risk of catastrophic fire is also important to the long term health of this subwatershed, as a hot wildfire that removed all of the vegetation in this steep area would likely lead to very high erosion rates. 27

28 Appendix A SURVEYING AND MONITORING PROCEDURES: Stream Condition Inventory Stream Condition Inventory plots were installed in summer 2004 and summer 2007, prior to any ground disturbing activity. These plots were completed on Cedar Creek at Alder Creek Campground, Cedar Creek at Cedar Creek Campground, Cow Creek, Ice House Creek, and Bear Creek just below the project area. Table 1 contains the location of these plots. Table 1 Location of the Stream Condition Inventory Plots in the Ice Timber Sale and Fuels Reduction Project Area Name Location Year of Survey Cedar Creek At Alder Creek Camp 2006 Cedar Creek At Cedar Creek Camp 2006 Cow Creek Below Black Sambo Mine 2006 Ice House Creek Below Alta Sierra 2003 Bear Creek Below Boy Scout Camp 2006 The purpose of the Pacific Southwest Region Stream Condition Inventory (SCI) is to collect intensive and repeatable data from stream reaches to document existing stream condition and make reliable comparisons over time within or between stream reaches. SCI is therefore an inventory and monitoring program. It is designed to assess effectiveness of management actions on streams in managed watersheds (non-reference streams), as well as to document stream conditions over time in watersheds with little or no past management or that have recovered from historic management effects (Frazier, et al., 2005). The SCI technical guide was developed in 1993 by a Pacific Southwest Region team of hydrologists, fisheries biologists, and mathematical statisticians from the regional research station. The intent was to select stream condition attributes and establish attribute measurement protocols that could be used across forest boundaries so that information could be shared across the region. Several criteria were established for selecting attributes: 28

29 Attributes were demonstrated through research to be able to detect change resulting from management Attributes could be sampled by field crews Attributes had a small enough measurement error to be useful in describing differences with a moderate to high level of confidence (detecting a 20% change with a confidence of 80%) The SCI consists of stream features, or attributes, that are useful in classifying channels, evaluating the condition of stream morphology and aquatic habitat, and making inferences about water quality. Attributes are collected at selected reaches on streams of interest. Reaches are monumented to reduce variability when measurements are repeated. The SCI attributes and protocols are designed to measure a suite of characteristics for inventorying stream condition at a specific time and place. SCI consists of established and proven stream assessment techniques that are organized into a package that can be measured in the field (Frazier, et al., 2005). The SCI plot will be installed pre project to define existing condition. The same site will be monitored post project to assess any affects of the project on water quality and watershed condition and to evaluate the effectiveness of the BMP s within the project area. Classification of Stream Channels Stream channels in the project area are classified using the Rosgen classification system (Rosgen, 1994). Within the Ice Timber Sale and Fuels Reduction Project, all channel types are A channels with dominate particle sizes from sand to gravel. The numeric value following each letter represents the dominate particle size. Some channel types include letters not capitalized and they are related to the channels gradient. A stream types range in slopes of 4 to 10 percent. They are entrenched and confined channels, giving them a low width/depth ratio and sinuosity. The typical A channel will have step-pool system morphology. Aa+ channel types are over 10 percent gradients. Due to high channel gradients and fine substrate, these streams are sensitive to disturbance, particularly A3 to A6 channel types. Recovery potential for these streams is very poor, with the exception of A1 and A2 channel types (Rosgen, 1996) which are a result of the bedrock/boulder substrate. C stream types have gradients ranging from 0.1 to 3.9 percent. They have a well established floodplain, moderate to high sinuosity, and a moderate to high width/depth ratio. These channels are considered to be sensitive to disturbances, especially C4, C5, and C6 stream types with a very high sensitivity rating. However, their recovery ratings range from fair to very good once the instability problem is corrected (Rosgen, 1996). 29

30 Table 2 shows the numeric value in the stream classification system. Streams dominated by bedrocks or boulders have the highest stability, highest recovery potential, and lowest sensitivity to disturbances. Otherwise the stream channels vary depending on slope and dominate particle size. Table 2 Sediment classification table associated with channel types. Number Sediment Type Range of Sizes (mm) 1 Bedrock 2048 and above 2 Boulders 256 to Cobble 64 to Gravel 2 to 64 5 Sand to 2 6 Silt/Clay Less than Determination of Riparian Ecotypes Previous stream surveys in the Ice Timber Sale and Fuels Reduction integrated Rosgen channel classification and key indicators from Pfankuch. Riparian ecotypes are designated from groups of Rosgen stream types that response similarly to natural events (floods and fire) and land management activities (grazing, timber harvest, roads, fuels management, recreation, etc.) relative to similarities in physical conditions. Channels are grouped to: 1. Identify key ecosystem elements that represent riparian ecosystem function and health 2. Describe riparian ecosystem existing conditions in terms of environmental indicators that are sensitive to change. To help identify key ecosystem elements environmental indicators for the individual riparian ecotypes were identified. The following table defines riparian ecotypes (Kaplan-Henry, 2000). 30

31 Table 3 Riparian ecotypes classification based on Rosgen (1994) classification systems and key indicators from Pfankuch (1978) stream stability analysis. Naturally-Stable Channels Rosgen Channel Type: A1, A2, B1, B2, B3, C1, C2, F1, F2, G1, G2 Restoration Not Required This ecotype is inherently stable and comprised of bedrock, boulder and cobble controlled channels. It is not significantly influenced by land management activities. Sediment build-up can be concerns in some locally impacted areas. Stable-Sensitive Channels Rosgen Channel Type: B4, B5, B6, C3, C4, C5, C6, E3, E4, E5, E6 This ecotype is inherently stable dominated by cobble, gravel, sand, and finer material. It is located in relatively flat riparian areas that are easily influenced by land management activities. This ecotype is comprised of streams typically associated with meadows with or without defined channels. This ecotype is stable and very susceptible to disturbances and changes in the flow, timing, and quality of water. Recover with Passive Restoration Unstable-Sensitive-Degraded Channels Rosgen Channel Type: G2, G3, G4, G5, G6, F3, F4, F5, F6, and those D3, D4, D5, D6 in unexpected geomorphic settings. Recover with Active Restoration This ecotype has been degraded and represents severe alteration of another riparian ecotype. In most cases, this ecotype represents the degraded form of Stable-Sensitive ecotypes that were formerly meadows. These ecotypes are comprised of down cut meadows with lowered water tables and abandoned flood plains. Meadow functions are not operating and vegetation is comprised of species that represent dry sites; accelerated erosion is common. A less common form of this ecotype is the altered form of the Naturally- Stable ecotype resulting from extensive accelerated sediment deposition on a course substrate. These areas exhibit braided characteristics the source of which is usually associated with upstream sites and/or deposition from off-site sources of sediment (roads, trails, campgrounds etc.) that has been transmitted to the site. Recovery usually requires active restoration measures. 31

32 Naturally Unstable Channels Rosgen Channel Type: A3, A4, A5, A6 (Landslide and Debris slide Terrain) Impractical to Restore This ecotype is typically eroded, steep, and unstable due to natural processes. It has a very high sediment load and is usually associated with debris avalanche or landslide terrain. These environments are sensitive to disturbance, and restoration is not practical due to a natural tendency for unstableness. Five attributes of Pfankuch identified as key indicators were used (Kaplan-Henry, 2000). The five attributes were tested by Myers and Swanson from a study done in northern Nevada in Myers and Swanson evaluated all of the Pfankuch indicators for observer variation and the relationship between Rosgen stream type and damage to the riparian resources from ungulates. Vegetative bank protection and bottom size distribution and percent stable material were among the indicators with the least observer variation. Vegetative bank protection, cutting, and bottom size distribution and percent stable material are reported to have a high probability for varying with riparian damage as per Myers and Swanson, Deposition has a lower probability for varying with damage however it is applicable for use in specific riparian ecotypes in the Sequoia National Forest. Determining the Range of Natural Variability Each stream survey collects a variety of data associated with various geomorphic characteristics of the stream. The range of natural variability is determined by certain characteristics within the surveyed reaches in the Ice Timber Sale and Fuels Reduction project. The channel type could change, i.e. a B3 channel type could change to a C3 channel type or a B5 channel type could change to a B3 channel type, causing the reach to exceed its range of natural variability; indicating a change in geomorphic characteristics such as entrenchment ratio, sinuosity, stream gradient, channel materials, and/or width to depth ratio. Each characteristic may fluctuate and still remain within natural variability. However, once a characteristic exceeds the range appropriate for the associated channel type others characteristics may also be adversely influenced, creating a change in channel type (see appendix A, figure 1). 32

33 Figure 1 Rosgen Classification of Natural Rivers Figure 2 Rosgen Classification of Natural Rivers 33

34 Figure 3 Modified Pfankuch rating system based on channel type (Graph created by Fluvial 34

35 Appendix B Sequoia CWE Terminology and Explanation CWE Terminology Equivalent Roaded Acres (ERAs) The model quantifies CWE's by calculating the number of Equivalent Roaded Acres (ERAs) a subwatershed contains. An ERA is equivalent to one acre of land that is completely roaded. The disturbance level of a particular management activity is quantified by determining the number of ERA s that would produce an equal impact. Some events and activities (i.e. fires, timber harvesting), are discrete events whose effects on the subwatershed and stream decrease over time and eventually cease altogether as the area becomes revegetated. A recovery period is assigned to events of this sort. Roads and trails provide a continuous source of disturbance and are modeled as such. A newly constructed road is given an initial disturbance value that decreases over three years to a baseline level. Unless the road is reconstructed or closed, the baseline value is then considered a constant impact that does not completely recover. Percentage of Threshold of Concern The Percentage of Threshold of Concern (% of TOC) is the models measure of the risk that a subwatershed may have large physical changes occur in the drainage (i.e. CWE's). These changes may result from natural catastrophic events (i.e. fires, floods, earthquakes, etc.) or management activities (i.e. roads and road construction, timber harvests, etc.). The CWE model calculates the number of Total Potential ERA's (the amount of ERA's available for management activities) a subwatershed contains. The Total Potential ERA's are a function of watershed size and physical characteristics (explained in further detail below, "Sensitivity Indices"). The % of TOC is calculated as the percentage of ERA's used by management activities of the Total Potential ERA's. A low % of TOC value (50% or less) indicates a low risk of CWE occurring as a result of the management activity. A high % of TOC value (80% or greater) indicates a high risk of a CWE 35

36 occurring as a result of the management activity. A low % of TOC value does not imply that a CWE will not occur, it simply indicates a low risk of a CWE occurring. A % of TOC value of 80% or greater does not imply that a subwatershed is already over threshold or that a CWE will definitely occur, it only indicates that there is a high risk of a CWE occurring. The % of TOC value is used to determine if a proposed management activity (along with past and current management activities) will put a subwatershed at a high risk of having a CWE occur. If a % of TOC value indicates there would be a high risk with a proposed activity in a subwatershed, then the activity could be modified to minimize risks, other mitigation measures could be done to minimize effects, or the proposed activity could be cancelled in that subwatershed. The Sequoia Forest agreed in the Mediated Settlement Agreement that a TOC value of 80% or greater would require further analysis before a proposed activity is initiated. CWE Model & Watershed Characteristics Considerations Sensitivity Indices Sensitivity indices (SI's) were developed for each subwatershed in the project area. SI's quantify the stability of a subwatershed. Evaluating the following physical characteristics of each subwatershed develops SI s: soils, topography, climate, geology, vegetation, and fluvial geomorphology. Soil: The potential for sheet or rill erosion is evaluated through the use of EHR's. A soil is assigned a low, moderate, or high rating. These ratings are based upon the following properties: texture, aggregate stability, climate, water movement through the soil, runoff, uniform slope length, percent slope, and soil cover. Soil conditions information was obtained from the 1996 Soil Survey of the Sequoia National Forest, California. Topography: Slope gradient is directly proportional to the potential for soil movement. The topography of the project area is grouped into slope categories: low (0-25%), moderate (26-40%), and high (>4l%). Climate: Climate is directly related to elevation zones. Three categories are used to determine erosion potential as a function of elevation: 36

37 Low rating for elevations above 6,000 feet, Moderate rating for elevations below 3,600 feet, High rating for elevations between 3,600 and 6,000 feet. During most storm events in the southern Sierra Nevada, precipitation is usually in the form of rain at lower elevations and snow at higher elevations. The transient snow zone receives a high rating due to the increased potential of rain on snow events that may cause extensive flood damage. Vegetation: Vegetation types are rated based on their ability to protect the soil surface from erosion. Vegetative cover intercepts rainfall, thus reducing raindrop impact, overland flow and sediment transport. Vegetation also improves the infiltration rate of a soil by creating macropores from root growth and micro sites of organic matter. Chaparral, shrubs, brush, or young plantation vegetation provide the least amount of protection (high rating), conifers provide moderate protection (moderate rating), and mixed hardwood/oak/grasslands typically provide the greatest protection from soil erosion (high rating). Geology: Geologic hazard areas are evaluated according to the potential for mass wasting. Geologic conditions are determined through the evaluation of geologically unstable lands within a subwatershed. Unstable lands are areas with active landslides, inner gorges, or fault zones. Fluvial Geomorphology: The existing stream channel condition reflects a watersheds ability to tolerate management activities. Stream channel stability evaluations assess current watershed conditions. Subwatersheds are given a low, medium, or high rating for this SI. Ratings for this SI are base on stream channel stability evaluations. Erosion Rates and Sediment Delivery Evaluations The CWE model considers disturbance levels for past and proposed impacts. Disturbance Coefficients (DC's) are calculated for disturbance activities. DC's are calculated as a function of the erosion rate, sensitivity factor, sediment delivery factor, slope factor, geologic erosion factor, and a routing factor. 37

38 Appendix C EROSION RECOVERY AFTER WILDFIRE AND OTHER DISTURBANCES IN THE SOUTHERN SIERRA NEVADA, CALIFORNIA USA 1 Neil H. Berg 2 and David L. Azuma 3 2 Hydrologist, Pacific Southwest Research Station, USDA Forest Service, 800 Buchanan St., West Bldg., Albany, CA nberg@fs.fed.us 3 Research Forester, Forestry Sciences Laboratory, USDA Forest Service, P.O. Box 3890, Portland, OR dazuma@fs.fed.us Keywords: fire recovery, surface erosion, wildfire, prescribed burn, southern Sierra Nevada, fuels treatments ABSTRACT Accelerated erosion commonly occurs after wildfire on forested lands and wildfire can appreciably increase surface erosion rates. As burned areas recover, erosion returns toward pre-fire rates as a function of many site-specific characteristics, including fire severity, vegetation type and climate. In some areas erosion recovery can be rapid, particularly where re-vegetation is quick. Erosion recovery after other, non-wildfire disturbances like prescribed burns, and other fuel reduction treatments, is less well understood. The rate of post-disturbance erosion recovery often conditions options for management of forested land, particularly in terms of cumulative watershed effects where the ramifications of future actions and resource recovery rates must be considered. Post-disturbance measurements of surface erosion and ground cover on over 600 plots in the southern Sierra Nevada between 2004 and 2006 suggest that after high, moderate or low severity wildfire rilling is seldom evident more than four years post-fire. The percent bare soil at the study plots generally did not significantly differ between reference and wildfire plots > 6 years old. No rilling was evident one to six years after treatment with a variety of fuel reduction techniques, including burning of machine- and hand-piled fuel, thinning, mastication and crushing and the percent bare soil at the fuel treatment plots did not differ significantly from reference conditions. These findings suggest that the study locations recovered from wildfire-induced surface erosion within a few years and that fuels treatments, particularly those incorporating little or no burning, exhibit no substantive evidence of post-treatment surface erosion. 38

39 INTRODUCTION AND OBJECTIVES Wildfires, prescribed burns and other disturbances to forests and grasslands can produce accelerated erosion (Roubichaud and Brown 1999; Roubichaud et al. 2000; Benavides-Solorio and MacDonald 2002). Although in many situations recovery, or return to pre-disturbance erosion rates, is rapid, in environments where post-disturbance re-vegetation is slow, recovery can take years (e.g., highelevation locations with short growing seasons). Post-disturbance erosion recovery often conditions options for management of forested land, particularly in terms of cumulative watershed effects where the ramifications of future actions and resource recovery rates must be considered. Post-disturbance management activities, including prescribed burns and silvicultural techniques aimed at reducing the risk of future wildfire by reducing fuel loads, can be constrained if erosion recovery is slow. The catch 22 trade-off associated with potentially elevated environmental effects stemming from wildfire can be ameliorated by fuel reduction activities only to the extent that the fuel reduction activities themselves, or in combination with earlier wildfires, do not cause unduly large environmental effects. A critical parameter for decision-makers is the duration of time required for recovery to occur after both wildfire and fuel management actions. Slow erosion recovery rates imply the need to spread out future management actions in time, or the need to lower their intensity, until recovery is substantially complete. Critical considerations are the total length of time to return to pre-disturbance erosion rates, and the variation in erosion rate prior to complete recovery. Erosion potential after wildfire has been found by many researchers to initially often be severe (Helvey 1980, Meyer and Wells 1997, Moody and Martin 2001), but diminishing within a few years to, or close to, background levels (DeBano et al. 1998, Robichaud and Brown 1999, Robichaud et al. 2000) Although there appears to be a general consensus that wildfire effects on erosion often ameliorate three to six years after a fire, recovery rates vary appreciably as a function of a variety of variables, including wildfire severity, rainfall intensity, vegetation type, soil type, topography and elevation (Stednick 2000). In terms of post-disturbance erosion, non-wildfire fuel reduction treatments benefit from their controlled nature. Factors influencing erosion potential can be addressed in prescribed burns, thinnings, and other fuel reduction treatments to lower erosion potential. For instance, because prescribed burns use lower severity fires, retain residual duff that protects the soil surface, and are mosaic in nature, prescribed burns are typically considered to produce less erosion than wildfires (Robichaud et al. 2005). Non-commercial thinning incorporating little or no yarding typically causes little post-treatment erosion (Robichaud et al. 2005). Appreciably less is known about post-disturbance erosion rates for mastication and some other fuel management treatments (Robichaud et al. 2005), although it is felt that masticating equipment can perturb or compact soil with a concomitantly increased likelihood of erosion. Ice (in 39

40 press) summarizes fuel management practices as causing small, short-term increases in sediment yields, but these increases are more than an order of magnitude less than those expected with a severe wildfire. This study refines understanding of post-disturbance erosion recovery in the southern Sierra Nevada of California. Specific objectives are to quantify the duration, magnitude and pattern of surface erosion recovery after wildfire and a variety of fuel management activities in the Sequoia National Forest and nearby areas. APPROACH AND METHODS During the summers of 2004 through 2006 field measurements were made at the Sequoia National Forest, the adjacent Tule River Indian Reservation and to the north in sections of Sequoia National Park and the Sierra National Forest (Figure 1). The study area includes the full spectrum of vegetation zones on the western side of the southern Sierra Nevada except the alpine. Annual precipitation varies on the field study plots from 20 to 125 cm (8 to 50 inches), and falls mostly between November and April when evapotranspiration is minimized. Elevations range from 610 m (2,000 ft) to 2650 m (8,700 ft) on the study plots. Granitic geology is predominant in the study area, although some volcanic and metamorphic rocks occur, with the metamorphics primarily as undifferentiated metasedimentary and metavolcanic rocks forming roof pendants. Soils formed on the granitic rock in particular can be highly erosive, and the modal classification of soil maximum erosion hazard on the study plots is high (USDA Forest Service 1996). We did not directly measure erosion rates because direct measurement (e.g., silt fences) requires at least several years to account for a representative range of climatic drivers (e.g., low, high and moderate precipitation years). As a proxy for direct measurement of erosion, we documented direct evidence of surface erosion, as the presence and frequency of rilling and gullying, and quantified percent bare soil (%BS) in transects at over 600 plots. A premise is that rilling and gullying are the most obvious signs of surface erosion and are a good indicator of the lack of return to pre-disturbance conditions. We traded space for time by assessing the erosion status of a variety of disturbances up to 27 years post disturbance. The use of %BS as a proxy for erosion is supported by field research in the western United States. For instance, Robichaud et al. (2005), citing other authors, stated Erosion rates tend to be positively correlated with percent bare soil and the amount of surface disturbance Benavides-Solorio and MacDonald (2002) add: In general, erosion rates are acceptably low when the proportion of bare soil is less than 30 to 40 percent. Simulated rainfall experiments also relate %BS to erosion (e.g., Percent bare soil was strongly correlated with increasing sediment yields [on burned ground in Colorado treated 40

41 with simulated rainfall] when all data were pooled (R 2 =0.81) Benavides-Solorio and MacDonald 2002). Other simulation and field studies have also shown post-fire reductions in sediment production with increasing vegetation cover (Wright et al. 1976; Wright et al. 1982; Morris and Moses 1987; Inbar et al. 1998; Robichaud and Brown 1999; Pannkuk et al. 2000; Benavides-Solorio 2003). A multitude of factors potentially influence the rate of forestland recovery after disturbance. We speculate that four primary factors condition the rate and pattern of post-disturbance erosion recovery: vegetation type, disturbance type, years after disturbance and wildfire severity (only for wildfires). We also documented other factors, including slope and aspect, soil erodibility, and precipitation as explanatory variables at each plot. Plot selection was based on the primary rather than the explanatory variables. A main objective was to extrapolate results beyond the specific measurement sites to a broader area. To help achieve this objective, plots were selected by incorporating a random component, and measurements were replicated. Replication allowed quantification of variability among plots that were otherwise anticipated to represent similar conditions (e.g., similar vegetation type, wildfire severity and years after disturbance). As the study progressed plots with direct evidence of erosion were often reassessed in subsequent years so that a majority of rilled plots were tracked for up to three years to document change through time. In addition four non-eroded plots were assessed a total of sixteen times to quantify within-year variation. All measurements and observations were made and recorded by the same individual. To balance available time with the desire for comprehensive data collection, we selected plots within one kilometer of roads on the basis that there is no known reason to expect that post-disturbance erosion recovery would differ as a function of distance from a road or trailhead. For safety reasons, sites having slopes greater than 75% were not surveyed. Strictly speaking, the results are limited to locations within 1 km of roads that slope less than 75%. Controlling Factors: Disturbance Type, Vegetation Type, Years after Disturbance and Wildfire Severity Disturbance Type Eleven disturbance types were identified from historical records and maps. Fire-related disturbances were wildfire, undifferentiated prescribed burns typically older than 5 years and recent broadcast burns. Non-fire-related treatments were thinning, machine pile and burn, machine pile, hand pile and burn, hand pile, mastication, and crushing. Plantations were also included. Although some 41

42 measurements and observations were made at locations having two disturbance types (e.g., wildfire overlying undifferentiated prescribed burn) an insufficient number of these combined disturbances were assessed to allow extrapolation to a broader population. Vegetation Type Five major vegetation types were identified: grass, hardwood, shrub, mixed conifer and conifer. Grass was limited to lower elevation savannah landscapes, not higher elevation meadows. Vegetation types were initially identified by Geographic Information System (GIS) data layers developed from data available in On-site determinations of vegetation type were also made, partly because vegetation type can change during the recovery period. The analyses were based on the vegetation type actually present at the site (versus the GIS-derived vegetation type). Years After Disturbance A primary objective of the project, to determine the duration of post-disturbance erosion recovery, addresses the time required for erosion rates to return to pre-disturbance levels. A wide range of recovery periods is conceivable. In warm environments with long growing periods and abundant water, recovery could be rapid, potentially within a year or two. Alternatively, at cold, high-elevation, dry and windy sites potentially recovery could require decades or longer. We anticipated that recovery would occur within 30 years after fire under any environmental condition. A 30-year stipulation for recovery length theoretically would require post-disturbance data for every year from the present back 30 years. This wasn t possible because of time and resource limitations and lack of necessary data for each year back thirty years. For instance, wildfire severity data are less abundant and less reliable for the early 1980 s and 1970 s compared to more recently available data. To address these constraints, for some analyses the 30-year post-disturbance period was segregated into five age groups as follows: 1-3 yrs after disturbance, 4-6 yrs, 7-10 yrs, 11-5 yrs, and > 15 yrs. Wildfire Severity Burned Area Emergency Rehabilitation (BAER) maps were the basis for determining wildfire severity. These maps are created immediately after each fire following a nationwide, standardized procedure (USDA Forest Service 2004). Given that variation in burn intensity can occur within a given mapping unit, the maps represent a rough tool for severity assessment. However, their availability back through time and the direct relevance of BAER severity determinations to post-fire erosion potential make them a primary source of severity information. From maps available at the Sequoia and Sierra National Forests three severity classes were initially identified: low, moderate and high. 42

43 BAER protocols describe the three severity classes as follows (Romme et al. 2003): High: areas of crown fire, i.e., leaves and small twigs consumed by the fire always standreplacing. Moderate: areas where the forest canopy was scorched by an intense surface fire, but the leaves and twigs were not consumed by the fire may be stand-replacing or not, depending on how many canopy trees survive the scorching. Low: areas where the fire burned on the surface at such low intensity that little or no crown scorching occurred (may include small areas that did not burn at all) never or rarely standreplacing. We adjusted the severity determination for recent wildfires based on on-site observation of needle presence. Approximately 15% of the high and moderate GIS severity classifications were adjusted based on on-site determinations. Field Plot Determination Field plot location was stratified by the primary controlling variables: disturbance and vegetation type, and years since disturbance, plus wildfire severity for wildfire sites. By stratifying wildfires on three variables, the matrix of cells required to comprehensively sample wildfires was large. With five vegetation types, three fire severity classes and six wildfire age classes, we needed to be survey 90 cells (5 x 3 x 6). A goal of three replicate plots per cell increased the theoretical number of plots for wildfires to 270. This large number of plots was reduced by several factors insufficient severity information for older age classes, absence of vegetation types in some age classes, logistical access problems, and classification of all grassland wildfires per Sequoia National Forest procedures--a priori as low severity. Even after these reductions, data collection from the total target number of plots for wildfires alone was anticipated to be marginally feasible. Wildfire selection was influenced by the availability of severity data with the population of available wildfires becoming those that had received BAER treatments and that were therefore relatively large (e.g., greater than 405 hectares (1000 acres) in area). Fewer plots were needed for the fuel treatments because fire severity was not relevant (all prescribed and broadcast burns were assumed to be of low severity and the other treatments did not incorporate fire other than the controlled burning of piled debris). The available database for wildfires and undifferentiated prescribed burns in the study area goes back several decades. Specifics on treatments of other types were available for only the last several years. 43

44 Explanatory Variables Ancillary variables may contribute to variation in erosion recovery. For each plot the following characteristics were determined Slope Aspect Elevation Visual evidence of disturbance from burning, grazing, harvested/cut wood, non-livestock animals (e.g., gophers) in three classes: absent, some, significant Soil erosion K factor (continuous value per the Universal Soil Loss Equation) Annual precipitation Bare Soil and Rill/Gully Quantification Ground cover was quantified by a point count variant of a procedure described in FIREMON, an interagency fire effects monitoring and inventory protocol (Fire Effects Monitoring and Inventory Protocol 2005). At each plot three parallel, cross-slope transects were randomly located along a 25-m (82 ft) baseline oriented directly upslope. Fifty point counts of ground cover were made at ½-m (1.64 ft) intervals along each transect. Five ground cover categories (dead vegetation, bare mineral soil, boulder/bedrock, down wood, live vegetation) were tallied. For each plot the percent occurrence of each category was recorded from the 150 points on the three transects. %BS was determined from the bare mineral transect counts. Direct evidence of erosion was quantified by tallying the number of rills or gullies that crossed transects on each plot. Analytical Procedures There are several ways of considering recovery from disturbances. In the context of this project, recovery could be considered to be complete when no evidence of rilling or gullying was observed at some time period after the disturbance. Another gauge of recovery is in comparison of bare soil amounts between disturbed and reference locations that were not disturbed. Both of these measures of recovery were incorporated into this project. Descriptive statistics, Mann-Whitney testing, discriminant analysis (Media et al. 1982) and logistic regression using S-Plus 7.0 (Insightful Corp. 2005) were used to assess the data. Discriminant analysis creates a function using associated variables that allocate an individual observation into one of two groups, with rills or without. Several discriminant models were conceived and examined by using crossvalidation to identify misclassifications. Logistic models were created using the General Linear Model procedure in S-Plus to determine the probability of rill occurrence based on the primary and secondary plot descriptors. 44

45 RESULTS AND DISCUSSION In summers 2004 through 2006 over 600 plots were surveyed (Table 1). Table 1. Distribution of Study Plots among Disturbance Types and Years since Disturbance Disturbance Type No. Assessments Years since Disturbance Percent of Assessments >15 Wildfire* 1 Assessment/plot Assessments/plot Assessments/plot Undifferentiated Rx Plantation Broadcast Burn Machine Pile/Burn Machine Pile Hand Pile/Burn Hand Pile Thinning Mastication Crushing Reference Within-plot** * Assessment per plot refers to the number of repeated wildfire assessments through time. For instance, 29 plots were assessed twice, in two different years. ** Four plots were monitored a total of 12 times in 2004 to quantify within plot variability. 45

46 Plots were surveyed on 14 wildfires occurring between 1977 and The ages (years since disturbance) of the wildfires surveyed ranged from 1 to 27 years at the year of survey. One hundred twenty-eight plots were assessed on low severity wildfires, plus 102 and 89 plots respectively on moderate and high-severity wildfires. Twenty-one prescribed burns were surveyed between one and 23 years after the initial burning. Between one and nine distinct units were surveyed at the more recent fuel treatment types (e.g., nine different hand pile and burn units were surveyed). Although a large number of plots were surveyed, because of the potential combinations of vegetation and disturbance types, years since disturbance and wildfire severity, relatively few plots were surveyed in any single combination of primary variables (e.g., three hardwood/low severity/14-year old wildfire plots). This small sample size issue added variability to the statistical analyses, but was countered by adding additional plots at younger disturbances when it became apparent that older disturbances showed little direct evidence of erosion. Consequently almost 70% of all assessments on non-reference plots were conducted on disturbances less than 6 years old. To further address the small sample size issue in some situations we combined conifer with mixed conifer. This combination was based on the presumption that conifer and mixed conifer vegetation function similarly in terms of post-fire ground cover recovery. The commonly-small sample size for each cell combination of disturbance type, age and wildfire severity (for wildfires) precluded the quantitative differentiation between linear and nonlinear recovery patterns; more data are needed to completely assess recovery pattern, particularly at varying years after the fires or burns. Rills and Gullies Active rills or gullies were initially found on one prescribed burn, one plantation, one broadcast burn and 27 wildfire plots. Another four plots exhibited re-vegetating rills. No rills or gullies were observed on the 101 plots on machine pile/burn, machine pile, hand pile/burn, hand pile thinning, mastication or crushing plots, all of which were less than 6 years old. With one exception, the rilled wildfire plots had burned four or less years prior to observation, with the percentage of rilled plots decreasing linearly with wildfire age (Figure 2). The single exception was a plot initially surveyed in 2004, 14 years after the Stormy Complex fire. On re-assessment of this plot in 2006 rills were still clearly apparent. The following focus is on rilled wildfire plots; rilling occurred too infrequently on other disturbance types to allow quantitative analysis. As well as appearing to linearly decrease through time with years after wildfire, rilling appeared to decrease with wildfire severity (Figure 3). For instance, over 50% of the 21 high-severity 2-year old wildfire plots were rilled, compared to 23% and 7% of the 2-year old moderate and low-severity wildfire plots respectively (Figure 3). The somewhat anomalous spike at 16 years in Figure 3 is due to the rilled 46

47 plot on the Stormy wildfire initially observed 14 years after the burn, and then again 16 years after. The percentage of rilled plots also decreased from high (16) to moderate (9) to low (7) severity. Compared to non-rilled wildfire plots, plots with active rills were associated with high %BS; only rilled wildfire plots had %BS values greater than 60 (Figure 4), and the median %BS differed substantially between rilled and non-rilled wildfire plots 53 and 13 respectively. The concurrence of moderate-to-high slope, high %BS and high severity segregates these conditions from non-rilled wildfire plots (Figure 4). Attempts were made to revisit twenty-three rilled wildfire plots one year, two years, or both one and two years after the original observation of rilling. Because in its initial inception the study did not anticipate re-visiting any plots, no plots were monumented and there was minor uncertainty in returning precisely to any plot in subsequent years due to imprecision in GPS capabilities. With this caveat, and on the basis of the observer s memory of rilled locations, it was nevertheless clear that many of the initially rilled plots were definitely returned to in subsequent years. Two-thirds of the revisited, rilled wildfire plots had active rills in both the second and third year. The number of active and re-vegetating rills per plot decreased over time (Figure 5). Twenty-one of the twenty-three revisited plots had fewer rills in the second or year of observation, with the median decrease in rill frequency three rills per year (range = 49 decrease/yr to 0.5 increase/yr). Seven initially rilled plots had no rills after the second or third year of observations. These findings suggest that rilling decreased through time at approximately the rate of three rills per year within the study plots, implying that locations with initially fewer than approximately nine rills per year could be expected to be rill-free four years after wildfire. Rill density generally increased with increasing %BS (Figure 6). Except for one plot with 49 rills, maximum rill frequency per plot was bounded by mean %BS as Rills/plot = 0.29 * mean %BS This relationship does not appear to be strongly influenced by wildfire severity. Bivariate plotting identified no other obvious relationships between rill presence or frequency and other primary or secondary variables. Although we felt that the classification of those observations with rills was extremely important, the best discriminant model using age, slope, %BS and precipitation--misclassified one-third of the plots with rills. This rate of misclassification of rilled plots is too high to consider the model adequate for our 47

48 purposes of predicting rill occurrence. The model did, however, correctly classify over 99% of the plots without rills as not having rills. In the logistical regressions, %BS reduced more of the residual deviation than any other independent variable. However, because we wanted to predict rill occurrence remotely, without visiting sites, we restricted model development by not including %BS. The resulting models were less powerful but identified years after wildfire and slope as significant variables, in that order of importance. Both the discriminant and logistic regression analyses identified only weak relationships between the independent variables and rill occurrence largely because the distribution of observations with rills was skewed, only a small portion of the dataset had observations with rills, approximately 10 percent of the observations. Although this skewness limited the power of the statistical testing, in the broader sense the skewness was a benefit in that relatively few locations were rilled, implying that surface erosion was relatively minor on the landscape scale at our plots even after high severity wildfires. The extent of surface erosion after high-severity wildfire in different soil, climatic and physiographic regimes could differ drastically from our results. Because there was little rilling on wildfire plots older than four years, it is tempting to conclude that rilling usually persists no longer than four years in the study area. For several reasons this conclusion is tenuous. Of the four four-year old wildfires surveyed only one, the 60,466 hectare (149,415 acre) McNally fire, had rills on the randomly chosen plots. However, a second four-year old wildfire had minor patches of rilling observed while moving between plots. In addition, the particularly barren appearance (with high %BS) of some of the four-year old, high-severity McNally rilled plots suggested rilling would persist at those plots. Also, no 5-yr old wildfires were surveyed because none existed in the study area during the survey period. Consequently the conclusion that rilling ends four years after wildfires may be more appropriate at the landscape scale, realizing also that the plots were not chosen for a high likelihood of rilling (e.g., in topographic convergence zones). Nevertheless, some of the barren four-year old McNally rilled plots were randomly selected to be in what were high-likelihood rilling zones. Results from this study support findings of others (MacDonald and Stednick 2003, Benavides-Solorio 2003) that evidence of post-wildfire erosion decreases with time after the fire and may not differ significantly from reference conditions after five to six years. Although this study did not attempt to directly quantify amounts of sediment produced after perturbations, findings from this study did not support findings by others that high severity wildfires produce more sediment than sites burned at moderate or low severity. We found a lower percentage of rilled plots on moderate and low severity plots than on high severity plots (Figure 4), but the frequency of active rills on plots did not differ appreciably by severity (Figure 6). An apparently new finding from this study is the quantified lack of evidence of surface erosion on plots treated for fuel reduction, particularly for treatments like mastication, crushing, and the various 48

49 machine and hand pile alternatives that use little or no fire. These results are not unexpected, a major intent of the design of these types of treatments is to minimize post-treatment erosion, but actual documentation of the effects of these types of treatments on surface erosion are scarce or non-existent (Robichaud et al. 2005). Percent Bare Soil Bare soil on the study plots varied by disturbance type, years after disturbance, and severity (for wildfires) and ranged from mean (or median) zero %BS to over one-third of the plot bare (Table 2). Table 2. Median/Mean %BS by Disturbance Type and Age of Disturbance Disturbance Type Years After Disturbance >15 All Wildfire Severity Low 14/21 24/24 6/11 4/9 8/10 10/19 Moderate 14/25 19/23 4/4 5/11 19/23 14/22 High 34/41 18/24 1/3 4/7 12/12 18/27 All Severities 20/27 20/24 5/8 4/9 10/13 15/22 Undifferentiated Rx 2/2 9/8 3/8 7/12 1/5 7/8 Plantation 35/35 20/19 9/12 17/12 17/18 18/18 Broadcast Burn 7/4 7/4 Machine Pile/Burn 4/5 4/5 Machine Pile 1/3 1/3 Hand Pile/Burn 2/5 2/1 2/4 Hand Pile 4/5 4/5 Thinning 2/4 2/4 Mastication 0/0 0/0 Crushing 3/5 3/5 Reference 4/7 Non-wildfire Treatments The first order interpretation of the tabular results is that because both the median and mean %BS values for the non-burn treatments (machine pile/burn, machine pile, hand pile/burn, hand pile, thin, mastication and crushing) are less than or equal to the median and mean reference plot %BS values, the 49

50 non-burn treatments do not result in more bare ground than reference locations. Because the median and mean %BS values for some of the undifferentiated prescribed burns, plantations and broadcast burns are both collectively and individually greater than for the reference locations, the first order interpretation is that there is more bare soil at these non-wildfire burn plots. To test these preliminary interpretations, we performed non-parametric Mann-Whitney analyses comparing both the grouped treatments (e.g., all non-burn treatments combined) and individual treatments (e.g., hand pile/burn) against reference %BS, by individual vegetation type (e.g., reference hardwood vs. prescribed burn hardwood). For these analyses, (1) because we believe conifer and mixed conifer locations to behave similarly in terms of erosion recovery, we grouped these two vegetation types, and (2) we restricted the analyses to treatment-vegetation type combinations with at least three plots, which limited the analysis of broadcast burns and machine pile treatments to conifer/mixed conifer and shrub only, and of machine pile/burn, hand pile/burn, hand pile, thinning, mastication and crushing to conifer/mixed conifer only. None of the Mann-Whitney tests for the individual non-burn treatments against reference conditions were significant (1-tail, α = 0.1, 0.05, or 0.01). Nor was BS% significantly greater (at α = 0.1, 0.05, or 0.01) for the prescribed burn plots in mixed conifer/conifer, hardwood or shrub vegetation, or the plantation plots in grass, than the reference plots. For prescribed burns greater than 15 years old, BS% did not differ significantly from reference conditions for mixed conifer/conifer, hardwood or shrub vegetation (sample size was too low to test for grass). BS% was significantly greater for the following conditions than for the comparable reference plots: Broadcast burn in conifer and mixed conifer vegetation (α = 0.1, 0.05 and 0.025, but not 0.01; all ages combined) Prescribed burn in grass (α = 0.1 and 0.05 but not or 0.01) with all ages combined Prescribed burn for the following ages-vegetation combinations: mixed conifer/conifer 4-6 years (significant at 0.1 and 0.05), mixed conifer/conifer years (significant at 0.1), hardwood 4-6 years (significant at all four α levels). Plantation in mixed conifer vegetation (all four α levels, all ages combined). When grouped neither the burn nor the non-burn treatments had significantly greater BS% than the grouped reference plots. The statistical testing confirms the first-order interpretation that %BS on the non-burn plots is not significantly greater than on the reference plots. The statistical testing confirms that some burn treatments did have significantly more %BS than the comparable reference plots, but when grouped together (i.e. combining prescribed burn and broadcast burn on all vegetation types) there was no significant difference from the reference plots. These findings support the rilling analysis in implying that the non-burn treatments do not initiate surface erosion at rates greater than under reference conditions. The detailed statistical assessment of prescribed burns suggests that in mixed 50

51 conifer/conifer, hardwood and shrub vegetation types %BS does not differ from reference conditions for burns greater than 15 years old. Wildfires On the premise that other research, and to some extent the rilling results from this study, suggests that five to seven years are required for surface erosion recovery after wildfire, we compared %BS on wildfire plots for two age groups, 1-6 years post-fire and 7 or greater years post-fire, against reference plots (Table 3). In these comparisons we grouped mixed conifer and conifer vegetation on the belief that post-fire erosion processes respond similarly on these two vegetation types. We also followed the practice on the Sequoia National Forest of operationally constraining wildfires on grass to low fire severity. Table 3. Mann-Whitney (one-tail) Test Results of Percent Bare Soil by Wildfire Severity, Vegetation Type and Two Post-fire Age Classes Wildfire Severity/ Vegetation Type Yrs Since Fire Significance Level Media n Wildfire %BS n Reference %BS Media n High Shrub 1-6 x x x Hardwood 1-6 x x x x Mixed conifer/conifer 1-6 x x x x Moderate Shrub 1-6 x x Hardwood 1-6 x x x x No plots Mixed conifer/conifer 1-6 x x x x x Low Shrub No plots Hardwood 1-6 x x x x x x x x Mixed conifer/conifer 1-6 x x x x x Grass 1-6 x x x x n 51

52 The statistical testing suggests %BS generally does not significantly differ between reference and wildfire plots > 6 years old. An exception is hardwood vegetation in low severity wildfires where %BS differed significantly from reference conditions for all four significance levels tested (0.1, 0.05, and 0.01). Mixed conifer/conifer vegetation also had significantly higher %BS on moderate and low severity wildfires for the highest significance level (0.1) evaluated. Plots surveyed 1-6 years after wildfire had significantly greater %BS for high severity fires (92% of the comparisons) and moderate severity wildfires (83% of the comparisons), but less so for low severity fires (75% of the comparisons). A relatively high percentage (80) of the hardwood wildfire plots had significantly greater %BS than the reference hardwoods, compared to 25%, 58% and 50% significant comparisons for shrub, mixed conifer/conifer and grass plots respectively. SUMMARY AND CONCLUSIONS lthough too few study plots showed direct evidence of surface erosion to allow development of stable discriminant or logistical regression models describing the quantitative effect of predictor variables on post-disturbance erosion, in almost all situations evidence of post-disturbance surface erosion was limited to wildfires less than four years old. The only other disturbance type with a moderately high evidence of erosion was plantations. There was neither direct evidence of surface erosion nor statistically significant differences in percent bare soil cover after mastication, thinning, hand pile and machine pile fuel treatments ranging from one to six years after treatment. Although we expect erosion from most wildfire situations ended within four years after the fire, in high severity fires under extreme conditions post-fire erosion could extend longer. The vast majority of eroded plots studied for multiple years had decreases in rill frequency with time, implying continuing recovery through time. In planning for future management activities on the Sequoia National Forest and parts of other forested locations in the southern Sierra Nevada, we see no reason to anticipate surface erosion to typically extend more than four or five years after some wildfires, and we found no direct evidence of surface erosion even the first year after currently used fuels treatments. Acknowledgments Brent Skaggs and Terry Kaplan-Henry provided invaluable advice and funding for this project. US EPA and the Pacific Northwest Research Station, USDA Forest Service, also provided funding. Rob Johnson graciously provided lodging during much of the fieldwork. Several discussions with Professor Lee MacDonald, Colorado State University, resulted in major improvements in the methodology used, and interpretation of the results. We thank the Tule River Indian Tribe for providing access to Reservation land. Daniel Neary, Peter Wohlgemuth and Lee MacDonald provided valuable comments in review of a draft version of this manuscript. 52

53 Literature Cited Benavides-Solorio, J Post-fire runoff and erosion at the plot and hillslope scale, Colorado Front Range. PhD Dissertation, Department of Earth Resources, Colorado State University. Benavides-Solorio, J. and L.H. MacDonald Post-fire runoff and erosion from simulated rainfall on small plots, Colorado Front Range. Hydrological Processes 15: DeBano, L.F., D.G. Neary and P.F. Ffolliott Fire's effects on ecosystems. New York: John Wiley & Sons. 333 p. Fire Effects Monitoring and Inventory Protocol (FIREMON) Helvey, J.D Effects of a north-central Washington wildfire on runoff and sediment production. Water Resources Bulletin 16: Ice, G. In press. The hydrologic consequences of wildfire and fuel reduction options: adding hydrologic models to a fuels and fire decision model. Proc. Watershed Management Council Conference. San Diego, CA. November 9-12, Inbar, M., M. Tamir and L. Wittenberg Runoff and erosion processes after a forest fire in Mount Carmel, a Mediterranean area. Geomorphology 24: Insightful Corp S-Plus 7.0 for Windows Westlake Ave. North, Seattle WA MacDonald, L.H. and J.D. Stednick Forests and Water: A state-of-the-art review for Colorado. Colorado State University. Colorado Water Resources Research Institute Completion Report 196. Meyer, G.A. and S.G. Wells Fire-related sedimentation events on alluvial fans, Yellowstone National Park, U.S.A. Journal of Sedimentary Research A67: Moody, J.A. and D.A. Martin Initial hydrologic and geomorphic response following a wildfire in the Colorado Front Range. Earth Surf. Process. Landforms 26: Morris, S.E. and T.A. Moses Forest fire and the natural soil erosion regime in the Colorado Front Range. Annals, Association of American Geographers 77: Pannkuk, C.D., P.R. Robichaud and R.E. Brown Effectiveness of needle cast from burnt conifer trees on reducing erosion. Pages 1-15 in 2000 ASAE Annual International Meeting. Paper Milwaukee, Wisconsin. Robichaud, P.R. and R.E. Brown What happened after the smoke cleared: onsite erosion rates after a wildfire in Eastern Oregon. Pages in Proceedings, American Water Resources Specialty Conference Wildland Hydrology. June 30-July 2,

54 Robichaud, P., J.L. Beyers and D.G. Neary Evaluating the effectiveness of postfire rehabilitation treatments. General Technical Report RMRS-GTR-63. Ft. Collins, CO. Rocky Mountain Research Station. 85 p. Robichaud, P.R., L.H. MacDonald and R.B. Foltz Fuel Management and Erosion. Chapter 5 in: Elliot, W.J. and L.J. Audin (eds.): Cumulative Watershed Effects of Fuels Management: A western synthesis. General Technical Report. Ft. Collins, CO. Rocky Mountain Research Station. Accessed on-line at Romme, W.H., Veblen, T.T., Kaufmann, M.R., Sherriff, R. and C.M.Regan Historical (pre-1860) and current ( ) fire regimes. Part 1: Ecological Effects of the Hayman Fire. Hayman Fire Case Study. USDA Forest Service General Technical Report RMRS-GTR-114, Fort Collins, Colorado Stednick. J.D Timber management. In: Drinking Water from Forest and Grasslands: A Synthesis of the Scientific Literature. USDA Forest Service General Technical Report SRS-GTR USDA Forest Service Soil Survey Sequoia National Forest California. USDA Forest Service, Pacific Southwest Region, Vallejo, CA. September pages plus maps. USDA Forest Service Forest Service Manual Emergency Stabilization Burned-Area Emergency Response. USDA Forest Service, Pacific Southwest Region, Vallejo, CA. Wright, H.A., F.M. Churchill and W.C. Stevens Effect of prescribed burning on sediment, water yield, and water quality from dozed juniper lands in central Texas. Journal of Range Management 29: Wright, H.A., F.M. Churchill and W.C. Stevens Soil loss, runoff, and water quality of seeded and unseeded steep watersheds following prescribed burning. Journal of Range Management 35:

55 Figure 1. Study Area in the Southern Sierra Nevada, California Sierra National Forest Study Area Sequoia National Park Study Area Sequoia National Forest & Tule River Reservation Study Area Appendix D 55