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HomeMy Public PortalAbout4-Wetland Monitoring Plan Revised 12-18-12Town of Truckee Brockway Trail Wetland Habitat Mitigation and Monitoring Plan Nevada County, California SPK-2009-00949 Project Applicant: Town of Truckee 10183 Truckee Airport Road Truckee, CA 96161 Prepared by: JBR Environmental Consultants, Inc. 595 Double Eagle Court, Suite 2000 Reno, Nevada 89521 Contact: Nancy Kang 775.747.5777 JBR Project B.A10444.00 Revised December 18, 2012 JBR Environmental Consultants, Inc. August 1, 2011 i Table of Contents Project and Mitigation Summary ................................................................................................ 1 Responsible Party.......................................................................................................................... 2 Existing Conditions ....................................................................................................................... 2 Mitigation Description .................................................................................................................. 3 Change in Wetland Functions...................................................................................................... 4 Success Criteria ............................................................................................................................. 6 Monitoring ..................................................................................................................................... 6 Maintenance Activities................................................................................................................... 7 Contents of Annual Monitoring Report...................................................................................... 7 Schedule ......................................................................................................................................... 8 Contingency Measures.................................................................................................................. 8 Long Term Management .............................................................................................................. 8 Appendices Appendix A Dominant Plants Observed (2009) Appendix B Annual Mitigation Success Reporting Form JBRENVIRONMENTAL CONSULTANTS,INC. Revised December 18, 2012 1 TOWN OF TRUCKEE BROCKWAY TRAIL MITIGATION AND MONITORING PLAN Project and Mitigation Summary The Town of Truckee (Town) proposes to construct a ½ mile of paved bicycle/pedestrian trail on the north side of Brockway Road that will establish a connection between two existing trail segments. The trail would start at the Truckee River Regional Park (east of Estates Drive), extends east across the edge of the Ponderosa Golf Course property and end at “The Rock,” approximately 250 feet northwest of the Brockway Road roundabout. The new segment of trail would be located in Section 14, Township 17 North, Range 16 East (Figure 1). The proposed trail will have unavoidable impacts to 0.035 acre of wetlands. To mitigate for impacts to wetlands, the Town proposes to remove a 0.056-acre mound of fill material from the same wetland and remove a culvert from a wetland ditch. The removal of 35 feet of culvert would re-establish wetlands along the bottom of the ditch and would prevent vehicles from accessing the interior of the property, thereby, protecting wetland and sensitive plant habitat. The area is currently used as an overflow parking area for the Truckee Rodeo and events at the Regional Park. In summary, to mitigate for 0.035 acre of fill to wetlands, the following is proposed: x Establish a 0.056-acre pocket sedge-dominated wetland within the wet meadow x Re-establish 0.008 acre of sedge-dominated wetland in the wetland ditch x Protect ~0.5 acre of seasonal wetland in the overflow parking area This report incorporates comments made by Tobi Tyler, Lahontan Regional Water Quality Control Board, during a site visit in October 2011. Changes made to the original August 1, 2011, Mitigation Plan that address Ms. Tyler's concerns include the following: x Native sedges will be planted at the bottom of the ditch after culvert removal x The target wetland community that will be established after the fill pile is removed will be dominated by sedges rather than wetland grasses x Achievement of 60% cover to demonstrate success It should be noted that Ms. Tyler originally asked for success criteria based on 75% vegetation cover. However, 60% cover is used in this plan because the typical cover in the adjacent, relatively undisturbed meadow is 60%. Approximately 40% of the ground cover is leaf litter built up from previous years. This cover value is documented in the wetland delineation report prepared in 2010. JBRENVIRONMENTAL CONSULTANTS,INC. Revised December 18, 2012 2 Responsible Party Jessica Thompson, P.E., Assistant Engineer Town of Truckee 10183 Truckee Airport Road Truckee, CA 96161 jthompson@townoftruckee.com 530-582-2932 Existing Conditions For the purposes of this Plan, the “site” refers to the property at the west end of the proposed trail alignment where wetland impacts and wetland mitigation are proposed (Figure 2). The site is surrounded by roads on three sides and the Truckee River Regional Park, Truckee Rodeo Grounds and the Ponderosa Golf Course. In August 2009, the U.S. Army Corps of Engineers (Corps) verified that the site contains 1.35 acres of potential wetlands, consisting of a wet meadow and a wetland ditch. Tire tracks are evident throughout the site indicating vehicle use during other times of the year when the soil is still moist. In the past, the site had been scraped and cleared of its original topsoil and vegetation community. Scrape marks are evident on aerial photographs (Figure 2). In the southwestern portion of the site, scattered red cinder rock on the soil surface suggests that the site was also used as a temporary stockpile area. Most of the site has been recolonized by a variety of grass species, and even contains Plumas ivesia (Ivesia sericoleuca), a rare plant. Due to the thinness of the soil substrate, the vegetation community is shorter-statured and goes to seed earlier than the more robust stands of vegetation occurring further east. Hydrology has also been significantly altered by Brockway Road and the wetland ditch. The construction of Brockway Road has likely contributed to the drying of the site. Before the current alignment of Brockway Road was built in 1960, the delineated wetlands were probably contiguous with the large wet meadow on the other side of the road. Now Brockway Road is a barrier, and no longer allows sheet and surface flows from the southwest to drain across the site. The wetland ditch flows west to east along the northern portion of the site (Photographs 4 and 5) flowing off the site into a constructed irrigation pond used by the Ponderosa Golf Course. The ditch and pond are shown on 1969 USGS topographic maps, indicating that it was contructed prior to 1969. The stream was probably channelized around the time when the Ponderosa Golf Course was constructed in 1961. The channel has “relatively permanent” flow that continues north toward the Truckee River through an obscure route through a residential subdivision. This ditch was once a natural channel that originated at springs on the slopes of “Hilltop” southwest JBRENVIRONMENTAL CONSULTANTS,INC. Revised December 18, 2012 3 and west of the project site. As the Brockway area was developed, the stream was channelized and now collects stormwater runoff from Palisades Drive and Brockway Road. The wetland ditch is deep enough to intercept the high water table and appears to be draining the western side of the parcel. The eastern side of the site contains a wet meadow created by high groundwater conditions early in the growing season. The wet meadow is dominated by Baltic rush (Juncus balticus)( F A C W , (OBL at the time of the delineation verification)) and long-stalk clover (Trifolium longipes) (FACW) with a smaller amount of common camas (Camassia quamash) (FACW). The wettest area is at the northeast corner next to the Ponderosa Golf Course irrigation pond. This area is dominated by water sedge (Carex aquatilis) (OBL) and Geyers willow (Salix geyeriana) (OBL). The driest portion of the wetland is next to the Brockway Road embankment. Here the wetland is dominated by grasses that tolerates shorter duration of wetland hydrology, including Sandberg bluegrass (Poa secunda) (UPL), meadow foxtail (Alopecurus pratensis) (FACW), and annual hairgrass (FACW). The wetland ditch supports mostly water sedge. Grasses dominate the upland areas. Sandberg bluegrass (Poa secunda) (UPL) was the most common, followed by meadow foxtail, annual hairgrass, and crested wheatgrass (Agropyron cristatum) (UPL). A 0.1 acre patch made up of 80 Plumas ivesia individuals also occur in the uplands. The Plumas ivesia is not a listed species, but California Native Plant Society designates Plumas ivesia as Category 1B.2. List 1B Plants are rare, threatened, or endangered in California and elsewhere. The “.2” indicates the species is fairly endangered in California, with 20-80% of occurrences threatened. Appendix A contains a list of species observed during a botanical survey conducted in 2009. In the future, a more comprehensive restoration of on-site wetlands will likely be a part of the Truckee Wetlands Restoration Project. The Truckee Wetlands Restoration Project would be proposed as a separate project, restoring the fragmented wetlands from the Hilltop area to the Truckee River. A feasibility study has already been completed by the Truckee River Watershed Council, and the project is in the next stage of planning and design. Mitigation Description The mitigation would consist of two areas of fill removal (Figure 2). Area 1 - Removal of the mound of dredge spoil Approximately 0.056 acre of dredge spoil would be removed from the wetland adjacent to the wetland ditch. The spoil pile is probably from a past ditch cleaning episode. Most of the upland mound would be removed except for (1) the area supporting a small pine tree, and (2) the top of the ditch bank. The pine tree would be left undisturbed. The berm at the top of the ditch bank that runs along the entire length of ditch would be maintained through the restored area. JBRENVIRONMENTAL CONSULTANTS,INC. Revised December 18, 2012 4 After removal of the mound of dredge material from the wetland, the newly exposed wetland surface would be further excavated. At least an additional 24 inches would be excavated to create a planting site that has seasonal wetland hydrology that extends well into the growing season. The newly created wetland site will be planted with sedge plugs and reseeded with wetland species that are present in the wet meadow. Target species and their wetland indicator status include the following: OBL Water Sedge Carex aquatilis FACW Northwest cinquefoil Potentilla gracilis FAC W Baltic rush Juncus arcticus (previously balticus) Seeds of target species will be collected on-site or purchased from a native seed nursery. A seedbed will be prepared prior to planting. Compacted soils will be loosened, as needed, to a depth of 6 inches. Seeding would occur in summer of fall to allow seeds to overwinter and take advantage of moisture provided by snowmelt in the spring. Seeds will be incorporated into the soil surface to a depth no deeper than one-half (½) inch. This would minimize the predation of seeds by wildlife while allowing seeds to overwinter on the soil surface. Sedge plugs can be harvested from the adjacent wetland or purchased from a nursery. If harvested from the site, the following steps are recommended: If plants are still green (i.e., not dormant), the leaves should be mowed/cut to four (4) inches. If the sedge plants are dormant, there is no need to trim the leaves. A sod cutter or shovel can be used to remove the root mass and soil with the plant material. Retain at least twelve (12) inches of soil to ensure sufficient rootmass is harvested. Once the plug is planted at the new location, it should be watered twice a week during the growing season. Less watering would be needed under cool temperature conditions. Water from the ditch will likely be available. Area 2 - Removal of the existing wetland ditch culvert crossing. Thirty-five feet of culvert would be removed, re-establishing 0.008 of wetlands in the bottom of the ditch. Water sedge is the dominant wetland plant in the ditch. Bare zones exposed by the removal of the culvert will be revegetated using sedge plugs taken from undisturbed portion of the ditch. Change in Wetland Functions Major functions provided by the site’s wetlands are described below. Functions that are not present are not discussed. Wildlife JBRENVIRONMENTAL CONSULTANTS,INC. Revised December 18, 2012 5 Onsite wetlands provide low quality wildlife habitat because the project site is disturbed and is surrounded by roads and development. The wetland ditch is a short isolated section and lacks adjacent wetlands and riparian that would be important for food and cover. 9 The mitigation would replace the small area of wetland wildlife habitat impacted by the trail. Sensitive Species Onsite wetlands provide marginal habitat for sensitive species. While the wetland ditch is potential habitat for mountain yellow-legged frog, the habitat is considered low quality because the ditch lacks a diversity of wetland plant and receives run-off from nearby roads. No frogs or tadpoles were detected during 3 visits to the site during the 2009 wildlife survey. 9 The mitigation would provide a small increase of frog habitat in the ditch. The offsite Ponderosa Golf Course irrigation pond is surrounded by a narrow band of Greyers willow, of which, a small patch occurs on the project site. State-listed willow flycatcher and Species of Special Concern yellow warbler were observed in the willows in 2009. Both species are known to prefer dense willow cover which does not occur at or near the project site. The willow flycatcher was determined to be a migrant, and the yellow warbler may possibly nest in the area but not at or immediately adjacent to the mitigation site. See Listed and Sensitive Species Assessment Brockway Road Trail (JBR 2009) for more details. 9 The construction of the trail would not remove willow habitat. A 0.1 acre patch of Plumas ivesia consisting of 80 individual plants, occurs next south and west of the wet meadow. The Plumas ivesia is designated by the California Native Plant Society (CNPS) as a CNPS 1B.2 species. List 1B plants are rare, threatened, or endangered in California and elsewhere. The “.2” indicates the species is fairly endangered in California, with 20-80% of occurrences threatened. The wet meadow is probably potential habitat for the Plumas ivesia. In the USFWS 1998 Wetland Plant Indicator List, the Plumas ivesia is rated as FAC, likely to occur in wetlands or non-wetlands (estimated probability 34-66%). The CNPS web site indicates the Plumas ivesia occurs in Great Basin scrub and lower montane coniferous forest habitat, in meadows, seeps, and vernal pools or vernally moist areas, usually in volcanic soils. A number of occurrences are reported in the Truckee area, mostly in areas with shallow clay pan soils. The absence of Plumas ivesia within the wet meadow suggests that the wet meadow provides marginal habitat. 9 The mitigation would remove vehicle access to the site. Barring vehicle access would prevent further degradation of ivesia and wetland habitat. Disturbance to approximately 0.5 acre of wetland and 0.1 acre of Plumas ivesia habitat would be removed. JBRENVIRONMENTAL CONSULTANTS,INC. Revised December 18, 2012 6 Water Quality The ditch carries stormwater runoff from surrounding roadways. The wetlands in the ditch improve water quality by filtering sediment and uptake of pollutants. This is important because the Truckee River is the receiving water. 9 If successful, the mitigation would incrementally increase water quality function by re- establishing 35 linear feet of wetlands along the bottom of the ditch. Recharge/Discharge The wetlands in the wet meadow and wetland ditch are the lowest areas on the mitigation site. The wetlands intercept the seasonally high water table and serve as discharge zones. The ditch appears to be draining the western portion of the mitigation site. 9 If successful, the mitigation would not change the wetlands’ recharge/discharge function. Success Criteria Re-establishment of wetlands would be considered successful when all of the following criteria are met: 1) 60% or more of absolute cover of vegetation in the re-established wet meadow 2) 60% or more of absolute cover of vegetation cover in the re-established wetland ditch 3) Vegetation meets 50/20 rule as described in the Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region (Corps 2010) 4) Hydrology meets wetland hydrology criteria using the Corps 1987 Wetland Delineation Manual and Regional Supplement 5) Less than 5% cover of noxious weeds in the re-established wet meadow and wetland ditch. The cover values in the success criteria above are based on actual cover values observed at the site. Use of hydric soil as indicator of success is not used because the site’s wetland delineation documented that wet meadow sites had marginal hydric soil characteristics. See Delineation of Wetlands and Waters of the United States, Brockway Road Trail, Nevada County, California (JBR 2009). Monitoring JBRENVIRONMENTAL CONSULTANTS,INC. Revised December 18, 2012 7 Mitigation monitoring should take place when the water table is at its peak. In 2009, peak hydrology was early in the growing season (May). Whether this is consistently true needs further investigation. Observing a high water table within the rooting zone of wetland plants is the easiest way to meet wetland hydrology criteria. However, observations made too early in the growing season would not capture the maximum vegetation cover. A second trip later in the growing season (i.e. June) may be needed. Wetland delineation data forms would be used to document vegetation and hydrology characteristics. Photographs taken from established photopoints would be used to further document vegetation cover. Compliance Monitoring will continue until success criteria area achieved. Maintenance Maintenance will include an annual inspection and weed control within 14 days of detection. The annual inspection would be performed as a part of the wetland monitoring described above. Because the areas of fill removal are small, the most efficient way to eradicate noxious weeds would be for the wetland monitor to hand pull weeds during the site inspection. Contents of Annual Monitoring Report A concise annual monitoring data collection form has been developed for this project to streamline data collection and reporting (Appendix B). The monitoring form will ensure the following requisite information will be submitted: 1) Name and contact information for Town of Truckee 2) Name and contact information of personnel conducting the monitoring 3) Date(s) the inspection was conducted 4) Photographs 5) Wetland delineation forms to document hydrology and vegetation success 6) Map showing locations of photographic reference points and sample sites 7) A table comparing the performance standards to the observed conditions 8) Statement on whether the success criteria are being met 9) Dates of any recent corrective or maintenance activities conducted since the previous report 10) Specific recommendations for any additional corrective or remedial actions The reporting form will be submitted to the Corps by December 31 of each year until success criteria are met. JBRENVIRONMENTAL CONSULTANTS,INC. Revised December 18, 2012 8 Schedule Remove fill material by October 2013 Plant Seeds by October 2013 Compliance Monitoring May and/or June 2014 Compliance Monitoring will continue until success criteria area achieved. Contingency Measures In the event that the revegetation of the two fill removal areas fail to meet success criteria, the Town will make an evaluation of the cause of failure and propose remedial measures. Remedial actions could include reseeding, replanting using different planting technique, using the In-Lieu Fee program or contributing funds to the Truckee Wetlands Restoration Project to meet its compensatory mitigation obligations. Funds to pay for planning, implantation, and monitoring of any contingency measures would come from Town of Truckee Department of Public Works. Long Term Management The parcel is owned by the Truckee-Donner Public Utilities District, and is operated and managed by the Truckee-Donner Recreation and Parks Department pursuant to previous agreements and easements. Both parties are jointly responsible for short-term and long-term management of the site. The removal of the existing culvert crossing ensures that wetlands and sensitive habitat will be protected from vehicle disturbance in the short-term. Long-term protection of the mitigation site will implemented as a part of the Truckee Wetlands Restoration Project. The Truckee-Donner Public Utilities District, the Truckee-Donner Recreation and Parks Department, and other partners in the Truckee Wetlands Restoration Project signed a letter of intent in January 2010, committing the partners to protecting the land on which the restoration occurs if the watershed restoration project is implemented. Figures Appendix A Dominant Plants Observed (2009) Dominant Vegetation Recorded Within the Project Area Scientific Name Common Name Indicator Species Abies concolor White Fir NI Achillea millefolium Common Yarrow FACU Agropyron cristatum Crested Wheatgrass NI Allium campanulatum Sierra Onion NI Alopecurus pratensis Meadow Foxtail FACW Arctostaphylos pungens Pointleaf Manzanita NI Arnica chamissonis Meadow Arnica FACW Artemisia tridentata vaseyana Mountain Big Sagebrush NI Calyptridium umbellatum Pussypaws NI Camassia quamash Common Camas FACW Carex aquatilis Water Sedge OBL Carex utriculata Northwest Territory Sedge NI Ceanothus cordulatus Whitethorn Ceanothus NI Collinsia parviflora Blue-eyed Mary NI Conium maculatum Poison Hemlock FAC Cryptantha torreyana Torrey’s Cryptantha NI Gayophytum diffusum Spreading Groundsmoke NI Deschampsia danthonioides Annual Hairgrass FACW Hordeum brachyantherum Meadow Barley FACW Ivesia sericoleuca Plumas Ivesia NI Juncus balticus Baltic Rush OBL Montia linearis Narrowleaf Miner’s Lettuce NI Nemophila pedunculata Littlefoot Nemophila NI Orthocarpus hispidus Bristle Owl’s-Clover FAC Pinus contorta Lodgepole Pine FAC Pinus jeffreyi Jeffery Pine NI Poa pratensis Kentucky Bluegrass FACU Polygonum bistortoides American Bistort OBL Potentilla glandulosa Sticky Cinquefoil FAC Potentilla gracilis Northwest Cinquefoil FACW Purshia tridentata Antelope Bitterbrush NI Ranunculus uncinatus Hooked Buttercup FAC Salix geyeriana Geyer’s willow OBL Taraxacum officinale Common Dandelion FACU Trifolium longipes Long-stalk Clover FACW Appendix B Annual Mitigation Success Reporting Form Town of Truckee Brockway Trail Project Wetland Mitigation Compliance Report SPK-2009-00949 Reporting Year The purpose of this annual reporting form is to record monitoring results in a concise way that saves on consultant costs. It was approved for use as a part of the Brockway Trail Mitigation and Monitoring Plan, April 28, 2011. Background Approximately 0.035 acre of wet meadow was filled to construct t ½ mile of paved trail on the north side of Brockway Road between Estates Drive and “The Rock” commercial complex. The terms of the Nationwide Permit required the Town of Truckee to re-establish 0.062 acre of wetlands on-site by removing a 0.056-acre mound of dredged material from a wet meadow and removing a 35-foot- long culvert from a wetland ditch. The wet meadow was reseeded with the following target species: Baltic rush Juncus balticus OBL, meadow foxtail Alopecurus pratensis FACW, meadow barley Hordeum brachyantherum FACW, and annual hairgrass Deschampsia danthonioides FACW. Target species for the wetland ditch was water sedge Carex aquatilis OBL. Permittee (Responsible Party) Monitoring Performed by Town of Truckee 10183 Truckee Airport Road Truckee, CA 96161 Contact: Contact: Year Fill Material and Culvert were Removed: Year Re-Established Wet Meadow was Reseeded: Year of 1st Compliance Report : Inspection Date(s): Date of this Report: Performance Standards vs. to Observed Conditions Performance Standard Observed Comments wet meadow Vegetation > 30% absolute cover Hydric vegetation meets 50/20 rule* Hydrology meets wetland delineation technical criteria* Noxious weeds < 5% absolute cover wetland ditch Vegetation > 35% absolute cover Hydric vegetation meets 50/20 rule* Hydrology meets wetland delineation technical criteria* Noxious weeds < 5% absolute cover * from Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region (Corps 2010) Has the mitigation achieved success criteria?Ƒ<(6 Ƒ12 Corrective or Maintenance Actions Taken (include date of action was taken): Corrective Actions Recommended: Attachments: Photographs of Re-established Wetland Meadow Delineation Data Form of Restored Wetland Meadow Photographs of Re-established Wetland Ditch Delineation Data Form of Restored Wetland Ditch Map Marked-up with Photograph Locations and Direction Submit reporting form and attachments by December 31 of each monitoring year to: U.S. Army Corps of Engineers, Sacramento District, Regulatory Division, 650 Capitol Mall, Suite 5-200, Sacramento, California 95814. Once success criteria are met, the Town of Truckee should request a written acknowledgement from the Corps verifying that mitigation and permit conditions have been successfully completed.