ELDORADO NATIONAL FOREST AMADOR RANGER DISTRICT AMADOR HIGH COUNTRY ROUTES PROJECT

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1 ELDORADO NATIONAL FOREST AMADOR RANGER DISTRICT AMADOR HIGH COUNTRY ROUTES PROJECT HYDROLOGY REPORT October 29, 2015 (Revised December 22, 2015) Steve Markman, Hydrologist Left photo. The Carson Emigrant Trail (17E24) crosses or borders a number of small meadows. Bottom photo. Portions of trail 16E26 are on top of a ridge above 8,000 feet in elevation. 1

2 EXECUTIVE SUMMARY This report analyzes the impacts to aquatic features that are likely to result from the Amador High Country Routes Project - referred to as the AHCRP in this report - in the Eldorado National Forest in northern California. The AHCRP sits at the headwaters of the Mokelumne River and South Fork American River of the Sierra Nevada Mountains. The landscape is mountainous and partially forested, and the elevation ranges between 7,600 and 9,800 feet. As a result of the elevation, most of the precipitation falls as snow between November and April - the hydrology is dominated by snowmelt from May through July. The AHCRP includes repairs to one or more specific locations on trails 17E24, 16E26, and 17E28 in order to reduce impacts to aquatic features and meet Standard & Guideline (S&G) #100 of the Sierra Nevada Forest Plan Amendment (SNFPA) of S&G #100 states: Maintain and restore the hydrologic connectivity of streams, meadows, wetlands, and other special aquatic features by identifying roads and trails that intercept, divert, or disrupt natural surface and subsurface water flow paths. Implement corrective actions where necessary to restore connectivity. Alternative 1 (Proposed Action) would result in the following effects: Four meadows would be brought into compliance with S&G #100. The meadows are 17E24-4, 17E24-5, 09N82-2, and 09N82-7. Trail 17E28 would contribute less runoff and sediment into a tributary of the Bear River where the trail crosses the stream, and additional widening of the stream channel as a result of trail 17E28 at this location would not occur. There would be no change or a negligible change in the amount of runoff and sediment from trail 17E24 into meadow 17E E24-3 is currently in compliance with S&G #100 as a result of corrective measures that were completed in June s 17E28-7 and 09N82-3 were re-evaluated in July 2015 and found to be in compliance with S&G #100. As a result, Alternatives 1 and 2 do not contain corrective measures at those two meadows. The effects from Alternative 2 are the same as for Alternative 1, with one exception. There would likely be erosion of several small ephemeral channels/draws at the locations where the re-route of trail 16E26 crosses those channels/draws, and some of the eroded sediment may eventually reach meadow 09N82-7. The three watersheds (7 th field) that contain the AHCRP are currently at a low risk of cumulative watershed effects (CWE). None of the alternatives change the risk of CWE in these three watersheds.. 2

3 AFFECTED ENVIRONMENT This report analyzes the impacts to meadows that are likely to result from the Amador High Country Routes Project, referred to as the AHCRP in this report. The AHCRP is located in the Eldorado National Forest in northern California. The AHCRP sits at the headwaters of the Mokelumne River and South Fork American River of the Sierra Nevada Mountains. The landscape is mountainous and partially forested, and is dotted with meadows, lakes, and outcrops of granitic and volcanic rocks. The elevation ranges between 7,600 and 9,800 feet. As a result of the elevation, most of the precipitation falls as snow between November and April - the hydrology is dominated by snowmelt from May through July. The meadows and stream crossing of the AHCRP are located in three watersheds (7 th field) as shown in Figure 1, and physical characteristics of the project area are summarized in Table 1. The meadows and stream crossing of the AHCRP are described in detail in Table 2 this includes the ratings of the meadows with regard to Standard & Guideline (S&G) #100 of the Sierra Nevada Forest Plan Amendment (SNFPA) of ,2 Photographs of trails and aquatic features are in Figures 2 through 9. Table 1. Physical characteristics of the Amador High Country Routes Project area. 1,2 Location Drainage basin Watersheds (7 th field) Climate Hydrology Project sites Beneficial uses of water Southern portion of the Eldorado National Forest (ENF) on the south side of highway 88. Southwest of Lake Tahoe, California. The project area is located at the headwaters of two drainages basins: South Fork American River and the Mokelumne River. Upper Bear River. 7,966 acres. ENF #1321. Upper Cole Creek. 10,098 acres. ENF #1421. Silver Fork American River Silver Lake. 9,567 acres. ENF #3861. Average annual precipitation is approximately 50 inches. Much of the precipitation falls as snow between November and April, although rain in the form of thunderstorms can occur in the summer. Dominated by snowmelt from late spring through early to mid-summer (May through July). This means that streamflows are often high during this time period, and then decline in late summer and fall (Aug. - Oct). 7 meadows and 1 stream crossing. The sites are described in Table 2. Project sites range between 7,880 and 8,920 feet in elevation. Municipal water supplies for domestic use; hydropower generation; contact and non-contact recreation; canoeing and rafting; cold freshwater habitat; spawning habitat; and wildlife habitat. There are no bodies of water on the 303(d) list in the three watersheds that contain the project (Figure 1). Land disturbances Land disturbances in the three watersheds consist mostly of roads, trails, and campgrounds, and associated parking areas. There are no towns or cities. 1 Beneficial uses of water are designated by the Central Valley Regional Water Quality Control Board (CVRWQCB). 2 Refers to Section 303(d) of the Clean Water Act, which gives states the authority to identify bodies of water that are impaired. 1 Standard & Guideline #100 states: Maintain and restore the hydrologic connectivity of streams, meadows, wetlands, and other special aquatic features by identifying roads and trails that intercept, divert, or disrupt natural surface and subsurface water flow paths. Implement corrective actions where necessary to restore connectivity. 2 The methodology for evaluating compliance with Standard & Guideline #100 is in Appendix A. This methodology is copied from the Supplemental Environmental Impact Statement, Eldorado National Forest Travel Management (USDA 2013). 3

4 Figure 1. Watersheds (7 th field) and selected aquatic features of the Amador High Country Routes Project. 4

5 Table 2. Summary of features included in the Amador High Country Routes Project (AHCRP). 1 Watershed (7 th field) Feature Description of Feature Rating with respect to Standard & Guideline (S&G) #100 and reason(s) for rating 2,3,4 17E24-3 adjacent to the east side of Mud Lake and adjacent to the west side of trail 17E24. (Figure 2). Rated as not meeting S&G #100 in July 2011 and September The reason was the erosion of sediment from a segment of trail 17E24 on the south side of Mud Lake into the meadow, which was causing a portion of the meadow to be less wet. Meets S&G #100 as of June Corrective measures were implemented in June 2015, as described in Appendix A. 17E24-4 crossed by trail 17E24 and crossed by two streams. (Figure 3). Rated as not meeting S&G #100 in September The reason was the erosion of sediment from a segment of trail 17E24 into the meadow, which was causing a portion of the meadow to be less wet. Upper Bear River (7,966 acres) 17E24-5 Several small meadows (close together) crossed by trail 17E24. (Figures 4 and 5). Rated as not meeting S&G #100 in September 2012 for two reasons: Erosion of sediment from a segment of trail 17E24 into the meadows such that portions of the meadows are less wet. Trail 17E24 intercepts groundwater from the meadows and routes the water down the trail. This is causing areas of the meadows to become less wet downhill of the trail. 17E28-7 adjacent to the south side of trail 17E28. Rated as not meeting S&G #100 in September The reason is because of erosional features (e.g. headcuts, channels) in the meadow, which are dewatering part of the meadow. Re-evaluated in July 2015 and rated as meeting S&G #100. The reason for this is described in a letter to the District Ranger; this letter is reprinted in Appendix A of this report. Stream crossing Tributary of the Bear River. (Fig. 6). No rating with respect to S&G #100. Not part of the meadow surveys in 2011 and Upper Cole Creek (10,098 acres) 09N N82-7 adjacent to trail 16E26. adjacent to trail 16E26. (Figure 7). Rated as not meeting S&G #100 in September Re-evaluated in July 2015 and rated as meeting S&G #100. The reason for this is described in a letter to the District Ranger; this letter is reprinted in Appendix A of this report. Rated as not meeting (S&G #100 in September 2011 for two reasons: Erosion of sediment from a segment of trail 16E26 into the meadow, which is causing a portion of the meadow to become less wet. Runoff from a segment of trail 16E26 is reaching the meadow and contributing to active channel erosion, which is contributing to the dewatering of a portion of the meadow. Silver Fork American River Silver Lake (9,567 acres) 09N82-2 adjacent to trail 17E24. (Figure 8). Rated as not meeting S&G #100 in September The primary reason was trail 17E24 is contributing runoff and sediment into a portion of the meadow. 1 The locations of the features are shown in Figure 1. 2 Standard & Guideline #100 states: Maintain and restore the hydrologic connectivity of streams, meadows, wetlands, and other special aquatic features by identifying roads and trails that intercept, divert, or disrupt natural surface and subsurface water flow paths. Implement corrective actions where necessary to restore connectivity. 3 The methodology for evaluating compliance with Standard & Guideline #100 is described in Appendix A. 4 Land disturbances other than those pertaining to S&G #100 are not described in Table 2. For example, signs of recent livestock use are evident in several of the meadows. 5

6 Figure 2. 17E24-3, which is adjacent to the east side of Mud Lake. Trail 17E24 is in the bottom of the photo, the meadow is in the middle of the photo, and a small portion of Mud Lake is visible in the upper center of the photo. June 23, E24-3 was rated as not meeting Standard & Guideline (S&G) #100 in July 2011 and September The reason was the erosion of sediment from a segment of trail 17E24 on the south side of Mud Lake into the meadow (to the left of the photo and not visible in the photo), which was causing a portion of the meadow to be less wet. Meets S&G #100 as of May Corrective measures were implemented on a segment of Trail 17E24 in May 17, 2015, as described in Appendix A. Figure 3. Trail 17E24 (middle of photo extending from the left edge of the photo to the right edge of the photo) crosses a stream (middle of the photo extending from near the top of the photo to the bottom of the photo) at 17E E24-4 was rated as not meeting Standard &Guideline #100 in September Runoff from the trail has eroded sediment from the trail into the meadow and two streams. 6

7 Figures 4 and 5. 17E E24-5 was rated as not meeting Standard &Guideline #100 in September E24-5 includes several small wet meadows that are close together, and trail 17E24 crosses the meadows near the west side of a ridge. The trail intercepts surface and subsurface water from the meadows and routes water down the trail. In addition, runoff from the trail has eroded sediment from trail 17E24 into the meadows. 7

8 Figure 6. Trail 17E28 crosses a tributary of the Bear River. July 2, Figure 7. 09N82-7 and trail 16E26 next to the meadow. September 29, Rated as not meeting S&G #100 in September 2011 for two reasons: a.) erosion of sediment from a segment of trail 16E26 into the meadow, which in turn is causing a portion of the meadow to become less wet, and b.) runoff from a segment of trail 16E26 is reaching the meadow and contributing to active channel erosion, which in turn is contributing to the dewatering of a portion of the meadow. 8

9 .Figure 8. 09N82-2. July 2, N82-2 was rated as not meeting S&G #100 in September The primary reason was trail 17E24 is contributing runoff and sediment into a portion of the meadow. 9

10 Figure 9. Landscape surrounding 09N82-7, as seen from the east side of the meadow looking to the west. 09N82-7- is the narrow strip in the middle of photo bordered by trail 16E26 (a white vehicle is on the trail). The distance to the meadow at this location is approximately 220 feet. September 28,

11 ENVIRONMENTAL CONSEQUENCES Analysis Framework This Hydrology Report only analyzes the Amador High Country Routes Project (AHCRP). Topics that were analyzed in the Travel Management Environmental Impact Statement (EIS) of 2008 and the Supplemental Travel Management EIS of 2013 for the Eldorado National Forest are not re-analyzed in this Hydrology Report. Alternative 1 - Proposed Action Four meadows (17E24-4, 17E24-5, 09N82-2, and 09N82-7) would be brought into compliance with Standard & Guideline (S&G) #100 of the 2004 Sierra Nevada Forest Plan Amendment (SNFPA). 1,2 This is because the repairs to improve segments of trails 17E24 and 16E26 of the four meadows, as described in Table 3 and illustrated in Figures 11 through 13, would result in the following: Runoff and sediment from trails 17E24 and 16E26 into the meadows listed above would be greatly reduced. The movement of surface water and subsurface water through meadow 17E24-5 would be improved.. There would likely be no change or a negligible change in the amount of runoff and sediment from trail 17E24 into 17E24-3 (east side of Mud Lake) for two reasons. Repairs to a segment of trail 17E24 near meadow 17E24-3 were completed in June These repairs, which are described in Appendix A, are expected to greatly reduce the amount of runoff and sediment from trail 17E24 that reaches meadow17e24-3. Trail 17E24 is currently being used by different types of motorized vehicles. The change in vehicle type designation on the northernmost 0.52 miles of trail 17E28 merely reflects the current use of that segment of the trail. Trail 17E28 would contribute less runoff and sediment into a tributary of the Bear River where the trail crosses the stream, and additional widening of the stream channel as a result of trail 17E28 at this location would not occur. This is because the trail approaches to the stream crossing, as well as short segment of the stream channel, would be reinforced with rock. Ground disturbance would occur in less than 10 percent of meadows and their associated Riparian Conservation Areas (RCAs). The primary reason for this is the size of the RCA surrounding a meadow is much greater than the size of grounddisturbing activities associated with Alternative 1. The RCA surrounding a meadow is 300 feet. The repairs to the trail would be confined to the width of the trail (approximately 15 feet) and a discrete number of small areas within 20 feet of the trail. 1 Standard & Guideline #100 states: Maintain and restore the hydrologic connectivity of streams, meadows, wetlands, and other special aquatic features by identifying roads and trails that intercept, divert, or disrupt natural surface and subsurface water flow paths. Implement corrective actions where necessary to restore connectivity. 2 The methodology for evaluating compliance with Standard & Guideline #100 is described in Appendix A. 11

12 If Alternative 1 (Proposed Action) does not occur, the following effects are expected to occur. Four meadows (17E24-4, 17E24-5, 09N82-2, and 09N82-7) would not be brought into compliance with Standard & Guideline (S&G) #100 of the 2004 Sierra Nevada Forest Plan Amendment (SNFPA). This is because the repairs to improve segments of trails 17E24 and 16E26 at the four meadows, as described in Table 3, would not occur. The overall condition of four meadows (17E24-4, 17E24-5, 09N82-2, and 09N82-7) may deteriorate in the longterm. This is because trail-generated runoff and sediment would continue to reach these meadows in the absence of the repairs described in Table 3. Trail 17E28 would continue to contribute trail-generated runoff and sediment into a tributary of the Bear River where the trail crosses the stream, and additional widening of the stream channel as a result of trail 17E28 at this location may occur. This is because the trail approaches to the stream crossing, as well as short segment of the stream channel, would not be reinforced with rock. There would be no ground disturbance in the Riparian Conservation Areas (RCAs) surrounding meadows 17E24-4, 17E24-5, 09N82-2, and 09N82-7. Alternative 2 The effects that would result from Alternative 2 are the same as for Alternative 1 (Proposed Action) except as described below for meadow 09N82-7. There would likely be erosion of several small ephemeral channels/draws at the locations where the re-route of trail 16E26 crosses those channels/draws, and some of the eroded sediment may eventually reach meadow 09N82-7. This is because the re-route of trail 16E26 would cross volcanic rocks and soils that are easily erodible, and the ephemeral channels/draws crossed by the re-route of trail 16E26 drain towards meadow 09N

13 Figure 10. Aerial view of 09N82-7 and the surrounding landscape, showing the existing location of trail 16E26 (western edge of meadow) and the approximate location of the proposed re-route of trail 16E26 (to the east of the meadow) in Alternative 2. 13

14 Table 3. Repairs to the routes that would occur under Alternatives 1and 2 of the Amador High Country Routes Project in order to meet Standard & Guideline #100. 1,2,3 Repairs under Alternatives 1 and 2 How repairs meet Standard & Guideline #100 17E E E24-5 Two rolling dips were constructed on a segment of trail 17E24 south (upslope) of meadow 17E24-3 in June This is described in Appendix A. Two rolling dips will be constructed in the trail on the east (uphill) approach of the two small stream crossings. Repairs to a 0.21 mile segment of trail 17E24 would include: Construction of approximately 4-5 rolling dips. Re-construction of 3 short segments of the trail, which includes raising the surface of the trail 1-4 ft. with material. Construction of two small crib walls within 2 road re-construction segments. Placement of aggregate base rock and/or riprap on the surface of trail 17E24-5. The rolling dips will divert most of the runoff and sediment from trail 17E24 into the forest before the runoff and sediment reaches meadows 17E24-3 and 17E24-4. This will greatly reduce the drying out of a portion of the meadows as a result of sediment from the trail being delivered into the meadows. The rolling dips will prevent runoff from flowing down trail 17E24 and road-generated sediment from entering meadow areas down-gradient of the trail. Re-construction of the trail will improve drainage of 3 short segments of the trail. The two crib walls will allow surface and sub-surface water (from meadows upslope of the trail) to pass through the trail (and into meadows downslope of the trail. 17E28-7 There would be no repairs to trail 17E28 at meadow 17E28-7. This is because meadow17e28-7 was re-evaluated in July 2015 and rated as meeting S&G #100. The reason for this is described in a letter to the District Ranger; this letter is reprinted in Appendix A of this report. Stream crossing 09N N N82-2 No rating with respect to S&G #100. Not part of meadow surveys in 2011 and There would be no repairs to trail 16E26 at meadow 09N82-3. The site was re-evaluated in July 2015 and rated as meeting S&G #100. The reason for this is described in a letter to the District Ranger; this letter is reprinted in Appendix A of this report. Alternative 1 3 to 10 rolling dips would be constructed in trail 16E26 on the northwest (uphill) approach to meadow 09N82-7. The 200 to 400 foot long segment of trail 16E26 immediately adjacent to the west side of meadow 09N82-7 would be armored with aggregate base rock or riprap. Alternative 2 3 to 10 rolling dips would be constructed in trail 16E26 on the northwest (uphill) approach to the meadow. A segment of trail 16E26 would be re-routed to the east of meadow 09N82-7, and most of the 0.32 trail re-route would be 150 to 400 feet from the meadow. The 0.23 mile long segment of trail 16E26 that currently borders the western edge meadow 09N82-7 and/or drains into the meadow would be rehabilitated, which includes: a) scattering woody material on the trail, c) re-seeding the area with native grasses, and d) blocking both ends of the trail with logs to prevent access by vehicles. One or two rolling dips will be constructed below trail 16E26 just upslope of meadow 09N82-2. Small check dams will be constructed on a steep section of the trail upslope of meadow 09N82-2. The rolling dips will divert much of the runoff and sediment from trail 16E26 into the forest before the runoff and sediment reaches meadow 09N82-7. This will greatly reduce the drying out of a portion of the meadow as a result of sediment from the road being delivered into the meadow, and may reduce the amount of downcutting of the stream channel. The 200 to 400 foot long segment of trail 16E26 immediately adjacent to the west side of meadow 09N82-7 would not erode sediment into the meadow. The rolling dip(s) and check dams will divert most of the runoff and sediment from trail 16E26 into the forest before the runoff and sediment reaches meadow 09N The location of the features is in Figure 1. The features are described in Table 2. 2 Standard & Guideline #100 states: Maintain and restore the hydrologic connectivity of streams, meadows, wetlands, and other special aquatic features by identifying roads and trails that intercept, divert, or disrupt natural surface and subsurface water flow paths. Implement corrective actions where necessary to restore connectivity. 3 The methodology for evaluating compliance with Standard & Guideline #100 is described in Appendix A. 14

15 Figure 11. Diagram showing the proposed repairs on a segment of the Carson Emigrant National Recreation Trail at meadows 17E24-4 and 17E24-5 that would occur under Alternatives 1 and 2 of the Amador High Country Routes Project. 15

16 Figure 12. An example of a rolling dip in a road. Surface water flows down the road from the right to the left, and then flows off of the road at the base of the rolling dip. Figure 13. An example of segments of a road covered with gravel. 16

17 Table 4. Summary of actions of Alternatives 1 and 2 with regard to applicable Best Management Practices (BMPs) in the 2011 Water Quality Management Handbook (Region 5, USDA). Actions that would occur under Alternatives 1 and 2 Applicable Best Management Practices (BMPs) with regard to Alternatives 1 and E E24-4 Two rolling dips were constructed on a segment of trail 17E24 south (upslope) of meadow 17E24-3 in June This is described in Appendix A. Two rolling dips will be constructed in trail 17E24 on the east (uphill) approach of meadow 17E24 and the two small stream crossings. BMP (Trail location and design) A re-route of trail 17E24 at meadow17e24-3 was considered impractical because the trail would cross steep, unstable volcanic terrain. A re-route of trail 17E24 at meadow 17E24-4 was considered impractical because it would cross the same two streams at locations that were not more favorable for stream crossings. BMP (Trail watercourse crossings) Trail 17E24 at meadow 17E24-3 does not cross any streams. Trail 17E24 at meadow 17E24-4 also crosses two small streams in addition to the meadow 178E24-4. The two rolling dips will divert most of the runoff and sediment from trail 17E24 into the forest before the runoff and sediment reaches meadow 17E24-4 and the two streams. BMP (Trail construction & reconstruction) A segment of trail 17E24 at meadow 17E24-3 was repaired and so as to improve the drainage of the trail and reduce impacts to meadow 17E24-3. The repairs are described in column 2. A segment of trail 17E24 at meadow 17E24-4 will be repaired so as to improve the drainage of the trail and reduce impacts to meadow 17E24-4. The repairs are described in column 2. BMP (Monitoring) Monitoring will occur as described in the Eldorado National Forest Travel Management SEIS Settlement Agreement Monitoring Plan (2015). 17E24-5 Repairs to a 0.21 mile segment of trail 17E24 would include: Construction of approximately 4-5 rolling dips. Re-construction of 3 short segments of the trail, which includes raising the surface of the trail 1-4 ft. with material. Construction of two small crib walls within 2 road reconstruction segments. Placement of aggregate base rock and/or riprap on the surface of trail 17E24. BMP (Trail location and design). Trail 17E24 crosses several small meadows/springs at 17E24-5. A re-route of the trail around all of these meadows/springs was determined to be impractical because the trail would cross other meadows/springs and/or steep unstable volcanic terrain or steep granitic terrain. BMP (Trail watercourse crossings) Trail 17E24 at meadow 17E24-5 does not cross any streams. BMP (Trail construction & reconstruction) The 0.21 mile segment of trail 17E24 at meadows 17E24-5 and 17E24-4 will be repaired so as to improve the drainage of the trail and reduce impacts to meadows/springs are crossed or bordered by the road. The repairs are described in column 2. BMP (Monitoring) Monitoring will occur as described in the Eldorado National Forest Travel Management SEIS Settlement Agreement Monitoring Plan (2015). 1 The complete text of all applicable BMPs can be found in the 2011 Water Quality Management Handbook (Region 5, USDA). 17

18 Table 4 (continued). Summary of actions of Alternatives 1 and 2 with regard to applicable Best Management Practices (BMPs) in the 2011 Water Quality Management Handbook (Region 5, USDA). Actions that would occur under Alternatives 1 and 2 Applicable Best Management Practices (BMPs) with regard to Alternatives 1 and 2 1 s 17E28-7 and 09N82-3 There would be no repairs to trail 17E28 at meadow 17E28-7 and no repairs to trail 16E26 at meadow 09N82-3. This is because both meadow were re-evaluated in July 2015 and rated as meeting S&G #100. The reasons for this are described in a letter to the District Ranger this letter is reprinted in Appendix A. As a result, meadows 17E28-7 and 09N82-3 meets the applicable BMPs, which include BMP (Trail location and design) and BMP (Trail watercourse crossings). 09N82-7 Stream crossing by trail 17E28 Alternative 1 3 to 10 rolling dips would be constructed in trail 16E26 on the northwest (uphill) approach to the meadow. The 200 to 400 foot long segment of trail 16E26 immediately adjacent to the west side of the meadow would be armored with aggregate base rock or riprap. Alternative 2 3 to 10 rolling dips would be constructed in trail 16E26 on the northwest (uphill) approach to the meadow. A segment of trail 16E26 would be re-routed to the east of meadow 09N82-7, and most of the 0.32 trail re-route would be 150 to 400 feet from the meadow. The 0.23 mile long segment of trail 16E26 that currently borders the western edge of the meadow and/or drains into meadow 09N82-7 would be rehabilitated, which includes: a) scattering woody material on the trail, c) reseeding the area with native grasses, and d) blocking both ends of the trail with logs to prevent access by vehicles. The trail approaches to the stream crossing, as well as eroding streambanks, would be reinforced with rock. BMP (Trail location and design). Alternative 1 does not re-route a segment of trail 16E26 around meadow 09N82-7. However, the actions to trail 16E26 under Alternative 1, as described in column 1, would improve the design of the trail by a) routing water and sediment off of trail 16E26 before reaching meadow 09N82-7 and, b) stabilizing the segment of trail 16E26 immediately adjacent to the meadow. Alternative 2 complies with this BMP because trail 16E26 would be re-routed to the east of meadow 09N82-7. BMP (Trail watercourse crossings) There would be no new watercourse crossings by trail 16E26 under Alternative 1. There would be several new crossings of ephemeral channels/draws by the construction of a 0.32 mile trail reroute under Alternative 2. BMP (Trail construction & reconstruction) The actions to trail 16E26 under Alternative 1, as described in column 1, would improve the design of the trail by a) routing water and sediment off of trail 16E26 before reaching meadow 09N82-7 and, b) stabilizing a segment of the trail immediately adjacent to the meadow. Alternative 2 complies with this BMP because the segment of trail 16E26 that borders the western edge of meadow 09N82-7 would be rehabilitated as described in column 2. BMP (Monitoring) Monitoring will occur as described in the Eldorado National Forest Travel Management SEIS Settlement Agreement Monitoring Plan (2015). BMP (Trail watercourse crossings) The trail approaches to the stream would be reinforced with rock. This will a.) greatly reduce the amount of sediment from the trail reaching the stream, and b.) prevent additional widening of the stream channel at the location where the trail crosses the stream. 1 The complete text of all applicable BMPs can be found in the Water Quality Management Handbook (USDA 2011). 18

19 CUMULATIVE EFFECTS The analysis of cumulative watershed effects (CWE) considers all past, present, and likely future land disturbances in a given drainage area. In the Eldorado National Forest (ENF), the major potential cumulative watershed effect is the degradation of habitat for aquatic and riparian species. This can result when land disturbances - roads, timber harvest, wildfire, etc. - increase the amount of sediment delivered to aquatic features. In the ENF, the risk of the occurrence of CWE for each watershed is assigned to one of the following four categories: low, moderate, high, or very high. The assignment of the risk of CWE is based on a quantitative evaluation of the land disturbances in the watershed using the method of equivalent roaded acres (ERA). The ERA method is described in more detail in Table 6. The three watersheds (7 th field) that contain the Amador High Country Routes Project (AHCRP) are currently at a low risk of CWE. This is because land disturbances in these watersheds, particularly in the areas near the sites of the AHCRP, are mostly confined to a relatively small number of roads/ trails, parking areas, and livestock use. An aerial view of a portion of these watersheds is in Figures 14 and 15. None of the alternatives change the risk of cumulative watershed effects (CWE) in the three watersheds (7 th field) that contain the AHCRP (Table 5 and Figure 16). This is because the amount of ground disturbance that would result from the AHCRP less 0.01 percent equivalent roaded acres at the 7 th field watershed scale - is negligible and far less than the 0.1 percent resolution of the ERA model at the watershed scale. Table 5. Risk of cumulative watershed effects (CWE) in the three watersheds that contain the Amador High Country Routes Project. 1,2,3,4 ERA - expressed as a percent of the TOC Watershed (7 th field) ENF Number Watershed Acres Risk of CWE in 2016 and all alternatives Upper Bear River ,966 Low Upper Cole Creek ,098 Low Silver Fork American River Silver Lake ,567 Low CWE = Cumulative Watershed Effects. ERA = Equivalent Roaded Acres. ENF = Eldorado National Forest. TOC = Threshold of Concern.. 2 Risk of CWE, expressed as a percent of the TOC: 0-49% = Low risk; 50-80% = Moderate risk; % = High risk; greater than 100% (greater than the TOC) = Very high risk. 3 No reasonably foreseeable land disturbances have been identified in these watersheds. In order for a land disturbance to be considered reasonably foreseeable, the number of acres, type of ground disturbance, and year(s) of disturbance must be identified. 4 Assumes that Alternative 1 (Proposed Action) and Alternative 2 would be implemented in

20 Figure 14. Aerial view of the landscape surrounding Mud Lake. May 26, North is to the top of the photo. 17E24-3 is on the east (right) side of Mud Lake, and trail 17E24 skirts the southeast edge of the meadow. Light gray areas are outcrops of granitic rocks, and light tan areas are volcanic rocks. Patches of snow (bright white) dot the landscape in late May. 20

21 Figure 15. Aerial view of the landscape surrounding the eastern portion of trail 17E24. July North is to the top of the photo. Light gray areas are outcrops of granitic rocks, and light tan areas are volcanic rocks. 21

22 Figure 16. Risk of Cumulative Watershed Effects (CWE) in expressed in terms of Equivalent Roaded Acres (ERA) as a percent of the Threshold of Concern (TOC) - for the watersheds (7 th field) that contain the Amador High Country Routes Project (AHCRP). 1 1 Assumes that Alternative 1 (Proposed Action) and Alternative 2 would be implemented in

23 Table 6. Description of the Method of Equivalent Roaded Acres (ERA) for assessing the risk of Cumulative Watershed Effects (CWE). Summary The risk of cumulative watershed effects (CWE) is assessed using the Equivalent Roaded Acre (ERA) method developed by R5 USFS. The process was further refined and adapted for the Eldorado National Forest (1993). In this method, an index is calculated for an entire watershed that expresses most land use in terms of the percent of the watershed covered by roads. Based on the ERA and a threshold of concern (TOC), a given watershed is assigned a relative risk low, moderate, high, or very high - of CWE. The primary cumulative impact of concern is an increase in sediment delivery to streams and degradation of aquatic habitat. Important aspects of the ERA method Roads, which are considered to have the greatest potential to increase runoff and sediment to streams, are given a value of 1.0. The number of acres of roads in a watershed is divided by the size of the entire watershed (in acres). This gives the percent of the watershed covered by roads. For each land disturbance activity other than roads, the number of acres is multiplied by a number less than 1.0. The result (for each land disturbance activity) is then divided by the number of acres of the entire watershed. This gives the percent of the equivalent roaded acres in the watershed for each type of land disturbance. The values for equivalent roaded acres for all of the land disturbance activities are added together. The final number represents the percent of the watershed that is covered by the equivalent of roads. The threshold of concern (TOC) is usually between 10 and 18 percent. That is, when 10 to 18 percent of a watershed is covered by the equivalent of roads, there is a very high risk that increased peak flows of streams and sediment delivery to streams will occur. This does not mean these effects will occur precisely when the ERA reaches the TOC, or that an increase in peak flows and sediment delivery to streams will automatically result in a degradation of fish habitat or diminish the experience of recreationists. It is merely a warning that cumulative effects might occur. Assumptions and limitations of the ERA method The method is intended for watersheds between 3,000 and 10,000 acres in size, although the method is commonly used for watersheds slightly outside of this range. ERA values, as well as the TOC, are only indicators of the risk of cumulative impacts occurring. They cannot be used to determine the percent or numerical amount of increase of sediment delivery to streams, stream channel eroded, fish habitat degraded or lost, or any other change in watershed condition. Such quantitative assessments require additional analysis. The location of land disturbance activities within a watershed is not considered. For example, roads near streams are treated exactly the same as roads that are far from streams. In reality, roads located within or next to riparian areas tend to contribute more sediment to streams than roads in upland areas. Recovery of the watershed from land disturbing activities occurs with time. For timber harvest activities, hydrologic recovery is assumed to be thirty years (i.e. ERA contribution is zero thirty years after timber harvest.) The ERA calculations do not take into account site specific BMPs that will be applied. ERA values start one year after a land use is implemented. Risk categories 1 Low risk of CWE - ERA is less than 50% of the Threshold of Concern (TOC). Moderate risk of CWE - ERA is between 50% and 80% of TOC. High risk of CWE - ERA is between 80% and 100% of TOC. Very high risk of CWE - ERA is greater than TOC. 1 Guidance to reducing the risk of CWE can be found in Section , Chapter 20 of the Soil and Water Conservation Handbook (USDA 1990). 23

24 References cited California Regional Water Quality Control Board, Central Valley Region Water Quality Control Plan (Basin Plan). The document can be found on the internet at USDA Forest Service. January Sierra Nevada Forest Plan Amendment, Final Environmental Impact Statement, Record of Decision. USDA Forest Service Final Environmental Impact Statement, Public Wheeled Motorized Travel Management EIS, Record of Decision. USDA Forest Service Water Quality Management Handbook. Region 5. USDA Forest Service Final Supplemental Environmental Impact Statement, Eldorado National Forest Travel Management. R5-MB

25 APPENDIX A. HYDROLOGIC INFORMATION Table A-1. Description of the field surveys of meadows in the Eldorado National Forest (ENF) in 2011 and Purpose of field surveys Standard and Guideline #100 Definition of a meadow 2 To determine if specific road or trail segments are causing adjacent meadows to not meet Standard and Guideline #100 of the Sierra Nevada Forest Plan Amendment of Maintain and restore the hydrologic connectivity of streams, meadows, wetlands, and other special aquatic features by identifying roads and trails that intercept, divert, or disrupt natural surface and subsurface water flow paths. Implement corrective actions where necessary to restore connectivity. A meadow is defined as a grassy opening, 0.1 acres or larger, dominated by perennial sedges, rushes, and grasses (wet meadow) or perennial grasses and forbs (dry meadow). Characteristics of a meadow 3 A meadow is an ecosystem type composed of one or more plant communities dominated by herbaceous species. It supports plants that use surface water and/or shallow groundwater (generally at depths of less than one meter). Woody vegetation, like trees or shrubs, may occur and be dense but are not dominant. Definition of hydrologic connectivity Methodology 4 The hydrologic connectivity of a meadow exists when the surface and subsurface flow of water through the meadow has not been visibly altered by the road or trail segment. Description. A field survey form for meadows was developed specifically to evaluate compliance with Standard & Guideline #100. The questions on page 2 of the survey form are specific to visible or noticeable evidence of alteration of the surface and subsurface flow of water through the meadow. The questions are qualitative, require hydrologic knowledge and field experience to answer, and are based on features that are visible at the ground surface, but reflect surface and subsurface water flow characteristics as described in the criteria below. 4 Assumptions The mere presence of a road or trail through or adjacent to a meadow (on-the-ground) does not determine if Standard and Guideline #100 is being met. This is because it is possible for a road or trail to occur within or adjacent to a meadow without a visible alteration of surface or subsurface flow of water into or through the meadow. A disruption of surface and/or subsurface flow in the meadow by a road or trail would result in evidence that can be seen at the surface, such as changes in vegetation, presence of deposited sediment, gullies, incised stream channels, etc. Criteria for rating Standard &Guideline #100 Roads and trails were rated as not meeting Standard & Guideline #100 if field evidence was visible that shows one or more of the following: The road or trail intercepts and diverts surface and/or subsurface water from the meadow and routes the water away from the meadow such that the meadow has decreased in size and/or wetness. Runoff from the road or trail has eroded sediment into the meadow such that the size and/or wetness of the meadow has been reduced. Runoff from the road or trail has caused a stream channel to downcut such that the water table next to the stream has dropped and the size and/or the wetness of the meadow has decreased. 1 Most of the field surveys were completed in Field surveys were completed by Steve Markman, Hydrologist, and Ryan Lockwood, Hydrologic Technician. 2 As quoted from the Land Resource Management Plan for the Eldorado National Forest of As quoted from the Hydrogeomorphic Types for the Sierra Nevada and Southern Cascade Ranges in California (USDA 2011). 25

26 4 The methodology was created by Steve Markman, Hydrologist, Eldorado National Forest. The detailed inventory method described in Groundwater-Dependent Ecosystems (General Technical Report WO-86a, March 2012) does not include a survey form that is specific to evaluating Standard and Guideline #100 of the 2004 Sierra Nevada Forest Plan Amendment. Carson Emigrant Trail 17E24 3 Route Repair update of June 23, 2015 I visited the site of 17E24-3 on June 23, The following repairs have been completed: The installation of two rolling dips on a segment of road 17E24 south (upslope) of 17E24-3. As a result of these repairs, it is my opinion that Standard & Guideline #100 is now met for 17E24-3. The reasons for this conclusion are described in the preceding page under Hydrologic Analysis. Additional features that were observed at the field site are described below. Several logs were placed on road 17E24 at one location. The primary purpose of the logs is to restrict vehicles to the main part of the road. The logs will also trap sediment that might otherwise reach 17E24-3. A small borrow pit, approximately 40 feet in length and feet in width, was constructed next to road 17E24. The borrow pit will not capture subsurface water from the meadow. This is because the bottom of the borrow pit is slightly above the elevation of the meadow - the borrow pit was excavated only few feet in depth into the side of a hill. A large outcrop of volcanic rock just upslope of the two rolling dips is eroding a material on to road 17E24. Over time, this may affect the function of the two rolling dips and maintenance of the rolling dips may be required in the future. The location of the features with respect to each other is shown in Figure 1. Photographs of several of the features are in Figures 2 through 4. Steve G. Markman, Hydrologist 26

27 Figure 1. Diagram of the features on trail 17E24 near 17E24-3 on June 23,

28 Figure 2. Rolling dip on road 17E24 upslope of 17E24-3. The rolling dip is in the center of the photo. The location of the rolling dip is shown in Figure 1. June 23, Figure 3. Logs on road 17E24 just downslope of the two rolling dips. The logs are in the middle of the photo on the left side. The primary purpose of the logs was to be to restrict vehicles to the main part of the road. The logs will also trap sediment that might otherwise reach 17E24-3. June 23,

29 Figure 4. Large outcrop of volcanic rock just upslope of the two rolling dips. Material is actively eroding from this outcrop of volcanic rock (middle of photo) and on to road 17E24 (lower part of photo. Over time, this may affect the function of the two rolling dips and maintenance of the rolling dips may be required in the future. June 23,

30 October 22, 2015 TO: Rick Hopson, District Ranger, Amador Ranger District, Eldorado National Forest. FROM: Steve Markman, South Zone Hydrologist, Eldorado National Forest. SUBJECT: s 17E28-7 and 09N82-3 with regard to Standard & Guideline #100 of the Sierra Nevada Forest Amendment of s 17E28-7 and 09N82-3 were rated as not meeting Standard & Guideline (S&G) #100 in September A re-evaluation of meadows 17E28-7 and 09N82-3 in July 2015 determined that the two meadows meet S&G #100 for the reasons described below. 17E28-7. The erosional features (e.g. headcuts, channels) in the meadow that are affecting the hydrologic connectivity of the meadow are not associated with trail 17E28. The erosional features are the result of a landslide upslope of the meadow that deposited a huge amount of sediment into the meadow. 09N82-3. The amount of sediment that has eroded from trail 16E26 and reached the meadow is negligible. As a result, the hydrologic connectivity of the meadow is not being affected by trail 16E26. Standard & Guideline #100 states: Maintain and restore the hydrologic connectivity of streams, meadows, wetlands, and other special aquatic features by identifying roads and trails that intercept, divert, or disrupt natural surface and subsurface water flow paths. Implement corrective actions where necessary to restore connectivity. Steve G. Markman 30

31 Background Information concerning Cumulative Watershed Effects. Definition of CWE Geographic scope of CWE Methods and limitations of assessing CWE The analysis of cumulative watershed effects (CWE) considers the impacts of all past, present, and foreseeable land disturbances. The land disturbances selected for the analysis of CWE include those that have the potential to result in erosion and an increase in sediment delivery to aquatic features. These land disturbances include, but are not limited to: past timber harvest (both in the National Forest and on private land), roads, fires, man-made impervious areas associated with buildings and other facilities, powerline corridors, and campgrounds. An increase in the amount of sediment delivered to aquatic features can result in a number of negative effects. 1 The 7 th field watersheds, which are generally 3,000 to 10,000 in size, that include the proposed land disturbance or changes in land disturbance. Sub-watersheds less than 3,000 acres in size may be delineated for analysis if land disturbances are concentrated in those areas. There are a number of methods currently used to assess CWE where the primary direct impact of concern is an increase in sediment delivery to streams and other aquatic features. None of these methods can quantitatively predict the amount of sediment delivered to streams, the distance downstream that the sediment load will travel, or point in time and the duration when an increase in sediment delivery to aquatic features will occur. The reasons for this include the large variability in the magnitude of direct effects from a given land disturbance, inability to predict secondary or indirect effects, lack of data on recovery rates for land disturbances, difficulty of validating predictive models on-the-ground, and the uncertainty of future events such as the size and timing of large storms. As a result, an assessment of CWE is frequently reported as an indicator of the overall risk of cumulative effects occurring in a watershed (Reid 1993; MacDonald 2000). Magnitude or severity of CWE Method of CWE used in the Eldorado National Forest The magnitude or severity of CWE following land disturbance depends largely on an event that cannot be prevented and the exact timing of which cannot be accurately predicted. It is whether a large storm event occurs within several years after land disturbances when the ground surface is vulnerable to erosion. If a large storm event does not occur within several after the land disturbance, the CWE to aquatic features will be minor, negligible, or absent. As a result of the importance of large storm events in determining actual erosion, sediment delivery to streams, turbidity and suspended sediment levels of streams, the land disturbances themselves in the watersheds play only a partial role in the severity of impacts to aquatic resources. The method selected for this CWE analysis is the method of Equivalent Roaded Acres (ERA). This method was developed by Region 5 of the U.S. Forest Service and adapted by the Eldorado National Forest (ENF). The method was specifically developed to assess the risk of CWE in forested watersheds where timber harvest and roads are major land disturbances. The ERA method has been used in the ENF for over 15 years, and nearly all of the 155 watersheds in the ENF have been evaluated with this method. This allows all of the watersheds in the ENF to be compared relative to each other in terms of the risk of CWE. Description of the method of Equivalent Roaded Acres (ERA) An index is calculated for an entire watershed that expresses most land uses in terms of the percent of the watershed covered by roads. Based on the percent ERA and a threshold of concern (TOC), a given watershed is assigned a relative risk low, moderate, high, or very high - of cumulative impacts. A very high risk is merely a warning that cumulative impacts such as an increase in sediment delivery to streams might occur. The ERA method has the same limitations as previously described for all commonly used CWE methods where an increase in sediment delivery to streams is the primary concern. 1 One well-documented cumulative effect is the reduction in the amount and quality of spawning habitat for resident fish as a result of fine-grained sediment deposited in the stream channel. 31