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HomeMy WebLinkAbout20011729 Ver 1_Mitigation Plans_20050723DR. J.H. CARTER III & ASSOCIATES, IN .R @ F 0 WP Do E 1C 1 nvironmenta onsu tants P.O. Box 891 • Southern Pines, N.C. 28388 JUN 2 2005 (910) 695-1043 * Fax (910) 695-3317 DENR - WArFR QUALITY jcamain@pinehurst.net WETLANDS AND STORMWATER BRANCH Letter of Transmittal To Mr. John Thomas, Regulatory Specialist U.S. Army Corps of Engineers Raleigh Field Office 6508 Falls of the Neuse Rd., Suite 120 Raleigh, NC 27615-6846 WE ARE SENDING YOU Date: 6-22-05 Job #: 9847-m Attn: Mr. John Thomas Re: Siler City Lower Reservoir Expansion Attached X Reports Maps Copy of letter Plans Data Prints Photos COPIES DATE # P s DESCRIPTION 2 22 June 2005 47 Final Wetland and Stream Channel Mitigation Plan for the Rocky River Lower Reservoir Expansion Project, Chatham County, North Carolina THESE ARE TRANSMITTED X For approval Approved as noted For your use Approved as submitted As requested Returned for corrections For review and comment For your information REMARKS: Please call with any questions or comments. COPY TO: ?tC ndi Karoly , NCDWQ (2 copies): SIGNED: Joel Brower, Siler City (2 copies) Glenn Dunn, Poyner and Spruill (1 copy) AM JA Bill Lester, HUA (2 copies) ho JVU If enclosures are not noted, please contact was imme iately Endangered Species Surveys • Environmental Assessments • Land Management • Wetlands Mapping and Permitting FINAL WETLAND AND STREAM MITIGATION PLAN FOR THE ROCKY RIVER LOWER RESERVOIR EXPANSION CHATHAM COUNTY, NORTH CAROLINA Prepared By: Dr. J.H. Carter III & Associates, Inc. Environmental Consultants 515 F Midland Road Southern Pines, North Carolina 28388 Submitted 22 June 2004 To: U.S. Army Corps of Engineers Raleigh Regional Office 6508 Falls of the Neuse Road, Suite 120 Raleigh, NC 27615-6846 North Carolina Division of Water Quality 401 Wetland Certification Unit 2321 Crabtree Blvd., Suite 250 Raleigh, NC 27604-2260 1930NS 3105 DEpS ANA s1oRNMlA E aW?H WE1? TABLE OF CONTENTS I INTRODUCTION ......................................................................................................................... 1 PROJECT SITE DESCRIPTION ............................................................................................... 2 ' IMPACTS DUE TO THE PROPOSED ROCKY RIVER LOWER RESERVOIR EXPANSION ............................................................................................................................. 5 ' Stream Impacts ............................................................................................................................ 5 Wetland Impacts ......................................................................................................................... 6 PROPOSED STREAM MITIGATION .................................................................................... 10 Deep River Restoration ............................................................................................................. 10 Off-site Stream Preservation in Randolph County .................................................................. 10 ' PROPOSED WETLAND MITIGATION ................................................................................ 12 On-Site Wetland Mitigation ...................................................................................................... 13 ' Mitigation Wetland-01 ......................................................................................................... 15 Mitigation Wetland-02 ........................................................................................................ 23 I Off-Site Wetland Mitigation ..................................................................................................... 30 Randolph County Mitigation Site ........................................................................................ 30 ' OTHER ACTIVITIES ............................................................................................................... 32 Fringe Wetlands ........................................................................................................................ 32 I Wetland Preservation/Enhancement within 100-foot Reservoir Buffer ................................... 32 Stream Enhancement within the 100-foot Reservoir Buffer ..................................................... 34 ' Stream Preservation within the 100-foot Reservoir Buffer ..................................................... 34 Replanting uplands within the 100-foot Reservoir Buffer ........................................................ 34 OTHER INFORMATION ......................................................................................................... 34 100-foot Buffer Encroachments ................................................................................................ 34 ' Electric transmission line easements .................................................................................. 34 ' Roads .................................................................................................................................... 38 Buildings .............................................................................................................................. 38 I Clapp Lake Dam .................................................................................................................. 39 1 MONITORING ACTIVITIES .................................................................................................. 39 Reference Forest Ecosystem ..................................................................................................... 39 On-site Wetland Mitigation Sites .............................................................................................. 39 Off-site Wetland Mitigation in Randolph County .................................................................... 43 Off-site Stream Preservation in Randolph County ................................................................... 43 Wetland and Stream Channel Enhancement and Preservation within the 100-foot Reservoir Buffer ............................................................................................................. 43 SUCCESS CRITERIA ................................................................................................................ 43 Wetland Hydrology ................................................................................................................... 43 Hydric Soils .............................................................................................................................. 44 Wetland Vegetation and Survival ............................................................................................. 44 REPORTING .............................................................................................................................. 45 Wetland Mitigation Sites .......................................................................................................... 45 Stream Mitigation Sites ............................................................................................................. 45 CONTINGENCY PLANS .......................................................................................................... 45 REFERENCES ............................................................................................................................ 47 11 LIST OF FIGURES Figure 1: Project location map, Rocky River Lower Reservoir expansion project, Chatham County, North Carolina .....................................................................3 Figure 2a -2c: Jurisdictional wetland and stream channel impacts for the Rocky River Lower Reservoir expansion project, Chatham County, North Carolina ...... 7-9 Figure 3: Wetland and stream channel boundaries and existing plant communities on the off-site mitigation property in Randolph County (Parcel No. 8735049459), Rocky River Lower Reservoir expansion project, Chatham County, North Carolina ...................................11 Figure 4: Location map of Wetland Mitigation-01 and 02 ............................................14 Figure 5: Photograph of existing conditions at Mitigation Wetland-01, Chatham County, North Carolina ..................................................................................15 Figure 6: Mitigation Wetland-01: Existing land uses ...................................................16 Figure 7: Mitigation Wetland-01: Soil map units for the Rocky River Lower Reservoir expansion project, Chatham County, North Carolina ...................17 Figure 8: Mitigation Wetland-01: Existing vegetative communities ............................18 Figure 9: Mitigation Wetland-O1: Proposed borrow areas ............................................20 Figure 10: Mitigation Wetland-O1: Grading plan ............................................................ 21 Figure 11: Stream channel design ................................................................................... 22 Figure 12: Photograph of existing conditions at Mitigation Wetland-02, Chatham County, North Carolina .................................................................................. 23 Figure 13: Mitigation Wetland-02: Existing land uses ................................................... 24 Figure 14: Mitigation Wetland-02: Soil map units for the Rocky River Lower Reservoir expansion project, Chatham County, North Carolina ................... 25 Figure 15: Mitigation Wetland-02: Existing vegetative communities ............................ 26 Figure 16: Mitigation Wetland-02: Proposed borrow areas ............................................ 27 Figure 17: Mitigation Wetland-02: Grading plan ............................................................ 28 iii LIST OF FIGURES (Continued) Figure 18: Mitigation Wetland-02: Typical cross section of an impervious ditch plug .............................................................:......................................... 29 Figure 19: General location of the off-site mitigation site in Randolph County (Parcel No. 8735049459), Rocky River Lower Reservoir... 31 Figure 20: Photograph of existing conditions at the off-site mitigation site in Randolph County, North Carolina ................................................................. 30 Figure 21: Soil map for the Randolph County mitigation site (Parcel No. 8735049459), Rocky River Lower Reservoir expansion project, Chatham County, North Carolina ................................................................. 33 Figure 22: Location of on-site stream channel enhancement and preservation within the 100-foot buffer Rocky River Lower Reservoir expansion project, Chatham County, North Carolina .................................................... 35 Figure 23a - 23b: Encroachments within the 100-foot buffer of the Rocky River Lower Reservoir expansion project, Chatham County, North Carolina ..............36-37 Figure 24: Location of Reference Forest Ecosystem (RFE) at Fox Lake for the Rocky River Lower Reservoir wetland mitigation sites, Chatham County, North Carolina .................................................................................. 40 Figure 25: Mitigation Wetland-O1 Monitoring Plan ...................................................... 41 Figure 26: Mitigation Wetland-02 Monitoring Plan ...................................................... 42 iv 11 LIST OF TABLES Table 1: Stream channel impacts for the Rocky River Lower Reservoir expansion project, Chatham County, North Carolina ..................................................... 6 Table 2: Proposed mitigation for stream channel impacts for the Rocky River Lower Reservoir expansion project, Chatham County, North Carolina ........ 10 Table 3: Summary of proposed mitigation for federal jurisdictional wetlands (7.67 acres) for the Rocky River Lower Reservoir expansion project . .............. Chatham County North Carolina ...................................................................12 Table 4: Summary of proposed mitigation for State jurisdictional isolated wetlands for the Rocky River Lower Reservoir expansion project . ................. Chatham County North Carolina ...................................................................13 Table 5: Proposed on-site wetland mitigation for the Rocky River Lower Reservoir expansion project, Chatham County, North Carolina ...................13 Table 6: Proposed off-site wetland mitigation for the Rocky River Lower Reservoir expansion project, Chatham County, North Carolina ................... 30 v FINAL WETLAND AND STREAM MITIGATION PLAN FOR THE ROCKY RIVER LOWER RESERVOIR EXPANSION CHATHAM COUNTY, NORTH CAROLINA USACOE Action ID No. 200220234 NC DWQ Project No. 01-1729 INTRODUCTION The Town of Siler City (Town) is proposing to construct a new dam structure immediately below the existing Rocky River Lower Reservoir dam in order to expand the existing Rocky River Lower Reservoir. The reservoir expansion will establish a water supply that will provide an additional 2.0 million gallons per day (MGD) to meet the Town's projected long-term needs beyond the current 20-year planning window through at least 2030, based on current population and demand projections. The project will result in the establishment of a 146.3-acre reservoir (including 24.4 acres of existing reservoir) and the preservation of an approximately 131-acre buffer zone that will be approximately 100 feet wide around the proposed reservoir. The project engineers, Hobbs, Upchurch and Associates, P.A. (HUA), are preparing a timeline that will outline the dam construction schedule and filling of the proposed reservoir. This timeline will be submitted as a supplemental document to this mitigation plan. Project construction will result in the loss of 9.19 acres of jurisdictional wetlands and inundation of 9,027 linear feet of perennial streams, 1,588 linear feet of intermittent streams and 3,242 linear feet of ephemeral streams. The majority of existing wetlands and streams have been adversely affected by human activities including cattle grazing. Over the life of the project, which has spanned approximately 8 years, improvements in surveying equipment and associated technologies have allowed for the collection of more accurate site information. This has resulted in minor variations in the final impact numbers compared to those in the Draft Wetland and Stream Mitigation Plan for the Rocky River Lower Reservoir Expansion Chatham County, North Carolina (Draft Mitigation Plan) QCA 2004). 1 Several elevation points were more precisely located; this in turn resulted in the refinement of the mapped location of several stream origin points. Overall the proposed impacts remain consistent with those reported in the Draft Mitigation Plan. The aerial topography completed in the early stages of the project was accurate enough to predict preliminary limits of the proposed reservoir. Changes to elevations within the proposed reservoir constituted the majority of the alterations later surveys revealed. As part of this project, the Town will work to improve the environmental quality of the project site and watershed as a whole. A 100-foot vegetative buffer around the expanded reservoir will be established and all wetlands and streams within this buffer will be preserved, enhanced or restored, as appropriate. Water quality and wildlife habitat will be enhanced by the formation of fringe wetlands, creation of 2 wetlands within the footprint of the proposed reservoir expansion and the restoration of a degraded wetland immediately adjacent to the reservoir. In addition to the on-site mitigation/restoration, the Town will purchase stream mitigation credits created by the removal of a dam on the Deep River, wetland acreage, and stream channel at the head of the Rocky River in Randolph County will be enhanced and preserved and pastures and croplands within the proposed 100-foot buffer will be replanted with appropriate upland tree and shrub species. PROJECT SITE DESCRIPTION The project area is located in western Chatham County in the east-central Piedmont of North Carolina (Figure 1). The topography ranges from gently to strongly sloping. Elevations within the project area range from 450 to 700 feet above Mean Sea Level (MSL). Geologically, the project lies within the Carolina Slate Belt of North Carolina. The soils are generally silt loams and silty clay loams, with the Badin, Cid, Lignum, Georgeville and Nanford Series being the most widespread. Soils along rivers and creeks, which ultimately drain to the Cape Fear River, are dominated by Riverview and Badin-Nanford soils (H. Outz, Chatham Soil and Water Conservation District, pers. comm.). The predominant natural vegetative communities as defined by the North Carolina Natural Heritage Program (NCNHP) (Schafale and Weakley 1990) were the Dry Oak-Hickory Forest on the ridgetops and upper slopes, Dry-Mesic Oak-Hickory Forest on mid-and lower slopes, Piedmont/Coastal Plain Heath Bluff on steep slopes and banks, Mesic Mixed Hardwood 2 0 IrBegin Prect c 3 F? ? ,_? ; ? ?• Ali n 4+ ' 7 s 7 ?*Yi ? i' r, ! ti` d I NA !` f end .PeofeC# ?.y? Figure 1. Project location map for the Rocky River Lower Reservoir expansion project, Chatham County, North Carolina. Prepared By: Dr. J.H. Carter III and Associates, Inc. Southern Pines, North Carolina 3 Forest on some lower slopes and along some well-drained small creek bottoms and Piedmont Alluvial Forest on river and stream floodplains. The Dry Oak-Hickory Forest was dominated by white oak (Quercus alba), southern red oak (Q. falcata), post oak (Q. stellata), blackjack oak (Q. marilandica) and hickory species, including mockernut hickory (Carya tomentosa) and pignut hickory (C. glabra). Shortleaf (Pinus echinata) and Virginia pines (P. virginiana) were also important components and dominated portions of this community type. Typical understory species included sourwood (Oxydendrum arboreum), red maple (Acer rubrum), flowering dogwood (Cornus florida) and sparkleberry (Vaccinium arboreum). Shrubs ranged from sparse to dense and included gooseberry (V. stamineum), lowbush blueberry (V. vacillans) and dwarf blueberry (V. tenellum). Herbs were generally sparse and included pipsissewa (Chimaphila maculata), oat grass (Danthonia spicata), rattlesnake weed (Hieracium venosum), goat's rue (Tephrosia virginiana) and greater coreopsis (Coreopsis major). The Dry-Mesic Oak-Hickory Forest was dominated by white oak and other oaks and hickories including northern red oak (Q. rubra), black oak (Q. velutina), shagbark hickory (C. ovata) and pignut hickory. Pines, tulip poplar (Liriodendron tulip fera) and sweetgum (Liquidambar styraciflua) were also common. Understory species included red maple, flowering dogwood, sourwood, American holly (Ilex opaca) and black gum (Nyssa sylvatica). Shrubs included gooseberry, dangleberry (Gaylussacia frondosa) and American strawberry-bush (Euonymus americanus). The herb layer was sparse and included heartleaf (Hexastylis arifolia), pipsissewa, rattlesnake plantain (Goodyera pubescens) and woodland tick-trefoil (Desmodium nudiflorum). Piedmont/Coastal Plain Heath Bluff contained an open to very sparse overstory of rock chestnut oak (Q. prinus) and shortleaf pine. A variety of trees from surrounding forests also occurred in this community as did a dense shrub layer dominated by mountain laurel (Kalmia latifolia). Herbs included galax (Galax aphylla), trailing arbutus (Epigaea repens), pipsissewa and partridgeberry (Mitchella repens). Dominant overstory species within the Mesic Mixed Hardwood Forest community included beech (Fagus grandifolia), northern red oak, tulip poplar and Florida sugar maple (Acer floridanum). Typical understory species included flowering dogwood, red maple and American holly. Common shrub species included horse sugar (Symplocos tinctoria), witch-hazel 4 I (Hammamelis virginiana), buckeye (Aesculus sylvatica), switch cane (Arundinaria tecta), American strawberry bush, beautyberry (Callicarpa americanus) and blueberries (Vaccinium spp.). Ground cover was moderately dense to dense and often diverse, and included Christmas fern (Polystichum acrostichoides), heartleaf (H. virginica), foamflower (Tiarella cordifolia), rattlesnake fern (Botrychium virginianum), alumroot (Heuchera americana) and lion's foot (Prenanthes serpentaria). Dominant overstory species in the Piedmont Alluvial Forest community type included river birch (Betula nigra), tulip poplar, sweetgum, green ash (Fraxinus pennsylvanica), black walnut (Juglans nigra), hackberry (Celtis laevigata) and sycamore (Platanus occidentalis). Typical understory species included boxelder (Acer negundo), red maple and ironwood (Carpinus caroliniana). Shrubs included American strawberry bush, spicebush (Lindera benzoin) and Chinese privet (Ligustrum sinese). The ground cover was generally dense and included vermin grass (Microstegium virmineum), bluestem goldenrod (Solidago caesia), heartleaf aster (Aster divaricatus), buttercup (Ranunculus abortivus), Canada avens (Geum canadense) and violets (Viola spp.). Vines were common and included poison ivy (Toxicodendron radicans), muscadine grape (Vitis rotundifolia), greenbrier (Smilax rotundifolia), Virginia creeper (Parthenocissus quinquefolia) and moonseed (Menispermum canadense). The entire site has been heavily disturbed by human impacts. Nearly one-half of the uplands have been converted to fields, pastures and rural residential areas. Forested areas were generally small and fragmented. IMPACTS DUE TO THE PROPOSED ROCKY RIVER LOWER RESERVOIR EXPANSION Stream Impacts On 18 March 2002, the United States Army Corps of Engineers (ACOE) visited the project site and made jurisdictional determinations on waterbodies therein. It was determined that some channels were nonjurisdictional due to the lack of stream characteristics and were either ditches or water impoundments. Table 1 details the linear footage of stream impacts approved by the ACOE. Table 1. Stream channel impacts for the Rocky River Lower Reservoir expansion project, Chatham County, North Carolina. Stream Type Linear Feet of Stream Channel Impacts Perennial-Forested 7,443.83 Perennial-Non Forested 1,583.56 Intermittent-Forested 1,200.23 Intermittent-Non Forested 387.60 TOTAL 10,615.22 A total of 13,857 linear feet of stream channels will be permanently flooded by the proposed project (Figure 2a-2c). Of this total, 3,242 linear feet are ephemeral streams, which do not require compensatory mitigation. The perennial and intermittent streams requiring mitigation total 10,615 linear feet (Table 1). Wetland Impacts Total jurisdictional wetland impacts reported in the Draft Mitigation Plan were 9.24 I L f acres. In April 2004, Dr. J.H. Carter III & Associates (JCA) determined by field verification that 0.05 acre of previously reported wetland impact was the result of mapping errors. This acreage occurs along Mudlick Creek and along the upper reaches of the Rocky River Lower Reservoir. The banks of Mudlick Creek and the Rocky River were surveyed using Global Positioning System (GPS) and these data were translated into a graphical representation. When an existing graphic of the Rocky River and Mudlick Creek were combined with the field data, portions of the banks of these waterbodies were erroneously reported as wetlands. Construction and operation of the proposed reservoir will actually impact 9.19 acres of jurisdictional wetlands, which are comprised of 1.52 acres of isolated wetland and 7.67 acres of riparian wetland. Figures 2a through 2c show the locations of the impacted wetlands. Nearly all of the wetlands to be impacted have been severely disturbed or are narrow riparian fringe. All wetland impacts will be the result of flooding. 6 Match Line Figure 2b ?J j General Location Map U l (j Legend Impacted Wetland Perennial Streams Intermittent Streams - Ephemeral Streams Existing Reservoir Boundary Proposed Reservoir Boundary 100 Foot Buffer 2 Foot Contours y ----- -- - ----- --------------- Matck-L-iu?aur 2b --- - A-V \"-- Figure 2a. Jurisdictional wetland and stream channel impacts for the Rocky River Lower Reservoir expansion project, Chatham County, North Carolina. N 0 215 430 860 Feet Prepared By: W E Dr. J.H. Carter III & Associates, Inc. `1 ?- 1 I I I I I Southern Pines, North Carolina June 6, 2005 S 7 ?l i Match Line Figure 2a Match Line Figure 2a f Legend Impacted Wetland , -Perennial Streams Intermittent Streams ® Existing Reservoir Boundary 2 foot Contours - Ephemeral Streams 100 foot buffer 1 Proposed Reservoir Boundary Match Line Figure 2c Figure 2b. Jurisdictional wetland and stream channel impacts for the Rocky River Lower Reservoir expansion project, Chatham County, North Carolina. Prepared By: 0 320 640 1,280 Feet Dr. J.H. Carter III & Associates, Inc. I I I I I I I I I Southern Pines, North Carolina June 6, 2005 N W E S 8 i i i i Match Line Figure 2b 1 f- f }I 1 Legend Impacted Wetland Perennial Streams Intermittent Streams - Ephemeral Streams ® Existing Reservoir Boundary 2 Foot Contours Proposed Reservoir Boundary 100 Foot Buffer Figure 2c. Jurisdictional wetland and stream channel impacts for the Rocky River Lower Reservoir expansion project, Chatham County, North Carolina. N Prepared By: W *.,E 0 465 930 1,860 Feet Dr. J.H. Carter III & Associates, Inc. I Southern Pines, North Carolina June 6, 2005 I I I ? I I I ? S 9 i i i PROPOSED STREAM MITIGATION To mitigate for stream channel impacts, the Town will purchase mitigation credits generated by the Carbonton Dam removal project on the Deep River and will preserve a portion of the Rocky River off-site. Table 2 outlines the proposed stream channel mitigation activities. The Carbonton Dam removal project will meet the Town's stream channel mitigation (restoration) requirements and the off-site stream channel preservation will be supplemental. Table 2. Proposed mitigation for stream channel impacts for the Rocky River Lower Reservoir expansion project, Chatham County, North Carolina. Mitigation Activity Mitigation in Mitigation to Mitigation Credit in Linear Feet* Impact Ratio Linear Feet (If) Deep River Restoration N/A . N/A 10,615.00 Off-site Stream Preservation- 2,660.00 10:1 266.00 Parcel No. 8735049459 TOTAL 2,660.00 10,881.00 if * Linear feet estimated Deep River Restoration The Town is purchasing 10,615 feet of stream channel mitigation credits (Table 2) generated by the Carbonton Dam removal project on the Deep River near the Lee-Chatham County line. The Carbonton Dam removal project will restore the natural stream channel characteristics and river flow of approximately 10 river miles of the Deep River. Off-site Stream Preservation in Randolph County On 1 September 2004, the Town purchased a 9.08 acre tract along the headwaters of the Rocky River in Randolph County for off-site mitigation (Figure 3). This stretch of the Rocky River is listed on the State's 303d list of impaired waterbodies due to agricultural uses associated with livestock grazing in adjacent riparian and/or upland areas (NCDWQ 2003). Approximately 10 Legend Mitigation ® Wetland Enhancement ® Wetland Preservation Stream Channel Preservation Vegetative Communities ® Mesic Mixed Hardwood Forest Disturbed Piedmont Alluvial Forest ® Piedmont Alluvial Forest \; 0 Tax Parcels - Roads WIN 11, '111 ?- / i t US HWY 421 r' r, GS, al Y P 4 S U 2 General Loca ' n Map Figure 3. Wetland and stream channel boundaries and existing plant communities on the off-site mitigation property in Randolph County (Parcel No. 8735049459), Rocky River Lower Reservoir expansion project, Chatham County, North Carolina. N Prepared By: Dr. J.H. Carter III & Associates, Inc. y?' E Southern Pines, North Carolina S 0 75 150 300 Feet June 6, 2005 11 ' 2,660 linear feet of stream channel will be preserved, which will help prove water quality downstream (Figure 3). ' PROPOSED WETLAND MITIGATION On-site wetland mitigation is preferred in order to maintain and improve the water quality of the proposed reservoir. Approximately 20.12 acres have been identified on-site for wetland mitigation. To mitigate for the 7.67 acres of impacted non-isolated wetlands, 4.49 acres of ' federally jurisdictional wetland and 1.52 acres of isolated wetland will be restored and 14.11 acres of wetland will be created. The restoration of the 1.52 acre isolated wetland will be ' considered as mitigation by the ACOE and DWQ. It is currently a State-regulated isolated wetland that will be restored to a federally regulated riparian wetland by reconnecting it to the riparian wetlands surrounding it. Also, 0.30 acre of wetland preservation and 3.23 acres of wetland enhancement will occur offsite. All mitigation properties will be preserved in perpetuity through deed restrictions that will be filed by the Town upon commencement of the project. ' Table 3 outlines the proposed activities needed to meet the wetland mitigation requirements for impacts regulated by the ACOE. Table 4 outlines the proposed mitigation ' needed to meet the requirements for isolated wetland impacts regulated by the DWQ. A detailed discussion of each proposed mitigation activity follows. t Table 3. Summary of proposed mitigation for federal jurisdictional wetlands (7.67 acres) for the Rocky River Lower Reservoir expansion project, Chatham County, North Carolina. Mitigation Activity Mitigation Mitigation to Impact Mitigation Credit Acreage Ratio Acreage On-Site Wetland Creation (MW-01 14.11 3:1 4.70 and MW-02) On-Site Wetland Restoration (MW-O 1) 6.01 1.5:1 4.01 Off-Site Wetland Preservation Randolph County 0.30 10:1 0.03 Off-Site Wetland Enhancement Randolph County 3.23 4:1 0.81 TOTAL 23.65 9.55 12 Table 4. Summary of proposed wetland mitigation for State jurisdictional isolated wetlands (1.52 acres) for the Rocky River Lower Reservoir expansion project, Chatham County, North Carolina. Mitigation Activity Mitigation Acreage Mitigation to Impact Mitigation Credit Ratio Acreage On-Site Wetland Restoration within MW- 1.52 1:1 1.52 01 TOTAL 1.52 1.52 ' On-Site Wetland Mitigation ' On-site wetland mitigation consists of restoration and creation of wetlands. Table 5 lists each on-site mitigation credit activity and Figure 4 shows the location of these mitigation sites ' [Mitigation Wetland (MW)-O1 and -02]. A discussion of these proposed mitigation activities follows. Wetland preservation and enhancement will occur within the 100-foot wide buffer of ' the proposed reservoir and several areas of fringe wetland are expected to naturally develop within the 100-foot buffer, however; these latter areas will not be counted as mitigation (see Other Activities). 0 0 Table 5. Proposed on-site wetland mitigation for the Rocky River Lower Reservoir expansion project, Chatham County, North Carolina. Proposed Mitigation for Wetlands Mitigation Acreage Mitigation to Impact Ratio Mitigation Credit Acreage MW-01 Creation 8.61 3:1 2.87 MW-01 Restoration 6.01 1.5:1 4.01 MW-02 Creation 5.50 3:1 1.83 Total 20.12 8.71 1 13 H:\SC9901-HW\8D0\LOCATION.dwg, LOCATION MAP, 6/21/2005 8:50:53 AM, dwilt, \\exchange\HPU50D0, 1:2.01693 g t ` Z O mG ? , p c II \ S 0 C 8 i G3 03 0 o? o? Z x o? a S 0 n-- L j?q n m? ..? Z55 co) > tiayc 4M MONS b Ills ?? p ROCKY RIVER LOWER RESERVOIR EXPANSION REVISIONS g If FOR THE Hobbs Upchurch & Associates PA. SYM. DESCRIPTION DATE BY , , TOWN OF SILER CITY , , Consulting Engineers 4 c rJ y CHATHAM COUNTY, NORTH CAROLINA SOUTHERN PM NC - CNARLOTM NC 4S. m 0 CD m NAGS HEAD. NC - RALEIGH, INC VaM E BE PREUMKAfl1 N LOCATION MAP FOR THE ROCKY RIVER . XH, SC - BEAUFM SC LOWER RESERVOIR MITIGATION 300 S.W. Broad Street, Southern Pines, North Carolina 28387 WETLAND-01 AND -02 Phone: (910) 692-5616 - Fax: (910) 692-4795 14 Mitigation Wetland-01 MW-01 consists of 14.62 acres and is located both within and adjacent to the Rocky C 0 River Lower Reservoir expansion project boundary (Figures 2b and 4). The majority of MW- 01 has been clear-cut, with the remainder being used as pasture. Elevation ranges from 538 to 542 feet MSL. It is bordered to the north by a pasture, to the west by alluvial forest, agricultural land and the Rocky River, to the east by thinned and unthinned upland hardwood forest and to the south by a clear-cut, upland hardwood forest and pasture. Figure 5 depicts the existing conditions at MW-01 and Figure 6 shows the existing land use and topography at 's this site. Wetlands on the site are mostly artifacts of human disturbances resulting from severe siltation that destroyed a stream channel (Figure 2b). Soils at MW-01 are mapped as the Nanford, Badin, Chewacla, Wehadkee, Peawick and Georgeville series (Figure 7) (USDAa unpublished). Historically, the predominant plant community on this site was mostly likely Piedmont Alluvial Forest. Figure 8 shows the existing vegetative communities at this site. The MW-01 site currently consists of 8.61 acres of upland, 4.49 acres of federally u n C jurisdictional wetland and 1.52 acres of isolated wetland under State jurisdiction. Of the 14.62 acres, 10.71 acres are located within the proposed reservoir pool and 3.91 acres are located outside the reservoir pool. The MW-01 site will create 8.61 acres of wetlands and restore 6.01 acres of wetlands, which will include filling 10.71 acres, grading 1.31 acres and connecting 2.60 acres of grazed pasture wetland to forested wetland. The creation of 8.61 acres of wetland will result from filling 7.3 acres of uplands located within the project site and grading an additional 1.31 acres of upland located outside the project boundary. Wetland restoration consists of filling 1.89 acres of federally jurisdictional wetland and 1.52 acres of isolated wetland and planting of 2.6 acres of wet pasture located outside of the proposed reservoir pool will be planted. The 1.52 acre isolated wetland will be connected to the surrounding federally jurisdictional wetlands and will no longer be isolated. Both the ACOE and DWQ have granted separate credits for the restoration activities that will to occur on these 1.52 acres. 15 Figure 5. Photograph of existing conditions at Mitigation Wetland-01, Chatham County, North Carolina. 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DESCRIPTION DATE BY TOWN OF SILER CITY Consulting Engineers `c CHATHAM COUNTY, NORTH CAROLINA SOUTHERN PINES, NC - CHARLOTTE; NC (n m NAGS HEAD. NC - RALEIGH, NC PRELUNAfI l Go 03 o N MITIGATION WETLAND-01 WRTLE BEACH SC - BEAUFORT, SC $ EXISTING LAND USES 300 S.W. Broad Street, Southern Pines, North Carolina 28387 Phone: (910) 692-5616 - Fox: (910) 692-4795 16 it sl fi <'p 7N Y p "k A. <r 50C= Nanford-Badin complex, 6-10% slopes 3A= Chewacla and Wehadkee soils, 02% slop 544A= Peawick fine sandy loam, 0-2% slopes, 232B2= Georgeville silty clay loam, 2-6% slot Figure 7. Mitigation Wetland-01: Soil map units for the Rocky River Lower Reservoir expansion project, Chatham County, North Carolina. 1Y -E Prepared By: 5 June 6, 2005 Dr. J.H. Carter III & Associates, Inc. Southern Pines, North Carolina Scale 1:2000 17 m m m m m m m m m m m m m m r r r m m H:\SC9901-HW\6DD\VegataWeCommunities.dwg, MM1 VegeCamm, 6/21/2005 1:33:42 PM, dwilt, \\exchange\HPU5000, 1:2.01693 0 0 ?x Z rA r p? OM CA rr??1 51* 4 ?rr iA Z o r rI 1 ?1 -m-,ri4? z 10 ;Dv a ?? w i t m J N v O L?LI L LLLLLL- ? LLLLI L LLLLL I ? I . ... LLLL, LLLLL?-Lt lCLN G v oil 41 yL Ll. LLLLLLL LLLLLI-•.LLL `- "L`LILLLLLLLLLLI.I.L LI. W V C 0 ^ LLLL?'?,LLLLLLLLLL LL L L` LLL LLL L LLL Ott tL L I N v _ . . LLLLL?LLLI.LLL Z LLLLL Q 0 9 A? 06 40 0, 1 1 / it, O N > \\ ?, a z6'? \? mvx s a '0 / $ b 0 x ? n omrn 1 ?U)> • a c) ) j 8 • CAM Z In"I ' O ¦ m z a U) ?°-i D n - o o D o - 0 I ? r ? m o e o T 1 ;0 0 m m m m -n pm n o ° Z ;a m m 0 w m m W 0 0 -< 0 Z I c o Z z m ^ V) ROCKY RIVER LOWER RESERVOIR EXPANSION FOR THE Upchurch & Associates, P.A. Hobbs • R-1-1 J DESCRIPTION DATE BY , lti E i C TOWN OF SILER CITY onsu ng ng neers `c CHATHAM COUNTY, NORTH CAROLINA SOUTHERN P#= NC - C94RLOTM NC (a m NAGS HEAD. NC -RALEIGH, NC PFELMYpIV1fl1 m o m AnRnE BEACH, SC - BEMJFVRL SC MITIGATION WETLAND-01 North Carolina 26367 Broad Street Southern Pines 300 S W EXISTING VEGETATIVE COMMUNITIES , , . . Phone: (910) 692-5616 - Fox: (910) 692-4795 18 The fill material for MW-O1 will be obtained from adjacent areas mostly within the proposed reservoir boundary and existing wetland soils will be stockpiled for use as topsoil (Figure 9). The 1.31 acre portion of MW-01 that is currently above grade will also be utilized as a fill source. Final elevations within the mitigation site will range between 540.6 and 541.3 feet above MSL, with a maximum elevation of 1 foot above the proposed reservoir's normal pool (540.3 MSL) (Figure 10). Site specific grading plans are shown in Figure 10. The 2.6 acre pasture wetland north of the constructed wetland will not be filled, graded or otherwise have its soils manipulated. It will be used for vegetative restoration only and will be planted with hydrophytic tree species. The hydrology for the constructed portion of MW-01 will come from several sources. First, the reservoir pool will be hydrologically connected to the northwestern and southeastern portions of the mitigation site (Figure 4). Additionally, a new channel will be created that will run the length of the mitigation site from northwest to southeast (Figure 6). This channel will have a near zero grade and will be a conveyance that is filled with water at the normal reservoir pool level. Due to the lack of grade, there will be no stream channel design and no mitigation credit will be requested. In addition, the braided stream channel that enters the mitigation site from the northeast (Figure 6) will be restored to the point where it connects with the created channel described above. It will be constructed to approximately match the grade of its source tributary in order to maintain flow into the reservoir (Figure 11). No mitigation credit will be involved with this activity. The 2.6 acre wetland, currently a livestock pasture, is located north of the constructed n wetland outside of the proposed reservoir pool boundary. However, it is directly linked to MW- 01. This site will be restored to a forested wetland by planting woody hydrophytic vegetation. This area will become part of the reservoir buffer making the buffer greater than 100 feet wide at this location. An additional 50 feet of buffer will be added to the north and east sides of this site in order to ensure that the restoration area is protected. Livestock will be excluded from the restoration itself is protected area by fencing. MW-01 will be planted with native wetland plants. The target vegetative community is the Piedmont Alluvial Forest with areas of Floodplain Pool and emergent wetland. The forest community will be created by planting hydrophytic species such as river birch, sycamore, hackberry, sweetgum, green ash and tulip poplar. The tree saplings will be planted using 19 i H:\SC9901-HW\800\BORROWAREAS.dwg, MW01 BORROW PM, 6/20/20051:31:36 PM, dwiR, \\ex&ange\HNJ5000, 1:2.01693 H:\ SC9901-HW \ 800 \ bUHHUW at-awg \ mwUI 1r-1 CD O n ? D r9- D fV C7 o ? a o? °o C?7 >a 0 0 o ? o O .0 O s x g N? > D \\\ 3/ 11???\c/j / 1111 111^?? ? mi/ 11111 r, \ _? 'p , `\?\\\\ \ \\\ \0 \\ 1111\IP\\\ A? / J j 111\\\\\y?\ I p? ?_? ? God r /G,////Ui?>p1?)\\\lllll/I/ Illllllllll??iiii?? I ///\\\?o_s = \\\1 )W /'o'ff//i ?'??? 1117/ / I p 141/1111 I I _ -- -1 I I 'Ifd%/Illllllllllljlllll\\l//j ?l l?f X711 \`\ i11t11)\ll \, ?? ?%?? /Il l ? ii / / I J JJJI!/gll7lgl 11111 /- \\1 III /J II =?=-1111)1)\ \ \\ G 41 --7 ?\ jl? Il 111111 IIIU1\1\ qlI \\, It N? \N I 1////////_\\Illl flJ//iii =??T\//// I /1\\\???\?\..\y\.\1??T%-= =?'\?\°;? \ ? % ?`„?-=__ C:) . \ 1111 r I ? ? ?i .ao? 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DESCRIPTION DATE BY m FOR THE , . . , p TOWN OF SILER CITY Consulting Engineers CHATHAM COUNTY, NORTH CAROLINA SOUTHERN PINES, NC "C C PRELIMINARY U) HE4D NC - RALEIGH, CO 01 m o m m MYRTLE BEACH, SC - BEAUFORT, SC w F N°o MITIGATION WETLAND-01 North Carolina 28387 Southern Pines Broad Street 300 S W u BORROW AREAS #1 AND #2 , , . . Phone: (910) 692-5616 - Fax: (910) 692-4795 zu H:\$C9901-HW\800\GRADING PLAN-MW 1&2.dwg, MW01 GRADING 120so1e, 6/21/2005 11:57:34 AM, dwiR, \\exthange\HPU5DD0, 1:2.01693 \ \ 529528 / ? \ ? ? \ \ \ \\\\ \ = ? ? \ v ? \ \\ 530 ?r \\\\ \ 531 / ?%C3', _..,? ?': / \\ \ \ \\\\`_\ ??\ \ \ \\?\ 532 ?....?`\ \\ 1 533 / ./ L ?. 1? ?. \ \ \? _ ? \ \\ ? _ •°\ ?\ \ \ 1 534 //? \ \ \1 \\ .\\? \ 535 Wp \1\ '9 ` 1 1 1\ 538 537 ( .? O? // / ,\ \ \ \ \ \ \\ \ ?\ \ O \ 535 539 / g y 23 ?? \ L 4e 1 -n rn / I I o oh" A; 1I1 \ vv vv_ -? I ?? 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SYM• DESCRIPTION DATE BY TOWN OF SILER CITY Consulting Engineers c CHATHAM COUNTY, NORTH CAROLINA SOUTHERN PINE'S. NC - I?NRLOTT& NC C) uDi m NAG'S HEAD, NC - RALEIGH, NO PREUMP AW O m o m - 0 VfflnE BEACH. SC - MUFW. SC r f r ro y " MITIGATION WETLAND-01 0 300 S.W. Broad Street, Southern Pines, North Carolina 28387 GRADING PLAN Phone: (910) 692-5616 - Fax: (910) 692-4795 21 H:\SC9901-HW\800\MWDETAILS.dwg, STREAM MITIGATION, 6/20/2005 3:31:41 PM, dwik \\exchange\HPU5000, 1:2.01693 9"A AE Z ?y MIDPOINT OF BEND 4e wauscma LA 0 r r r ?z C B r m Z, oD z§ o \ z r ? ?? r ? ? C Z r DO DO z ; MIDPOINT OF BEND r r • ? °m g? z ?Z s r r L--j w Q? (n QN z m 9 m p 0 ?o Z o Z $ ? ao Z D ; Ou D 20' BELT WIDTH 511 of 0 ROCKY RIVER LOWER RESERVOIR EXPANSION REVISIONS FOR THE Hobbs, Upchurch & Associates, P.A. SYM. DESCRIPTION DATE BY TOWN OF SILER CITY Consulting Engineers `c CHATHAM COUNTY, NORTH CAROLINA SOUTHERN PIME% NC - CHARLOTTE. NC CD o m m HAGS HEAD. NC - RALEIGH, NC f f1GL.11111pV1f1 -? o 0 0 No MYRTLE REACH, SC - BEAUFORT, SC Z g STREAM CHANNEL DESIGN 300 S.W. Broad Street, Southern Pines, North Carolina 28387 Phone: (910) 692-5616 - Fax: (910) 692-4795 22 I 0x10 foot spacing (or less), with at least 435 trees per acre, and will be fertilized in their first and second years. Herbaceous species such as soft rush (Juncus effusus), woolgrass (Scirpus cyperinus) and sedges (Carex spp.) will colonize the pool and marsh communities. Mitigation Wetland-02 MW-02 consists of 5.50 acres, 5.40 acres of upland and 0.10 acre of wetland, within the Rocky River Lower Reservoir project boundary. The general location of MW- 02 is shown in Figure 5. This area will be flooded as a result of the proposed project. It is currently being used for agriculture (Figure 12) with narrow strips of hardwood trees along 3 drainage ditches. Elevation ranges from 536 to 542 feet above MSL. The site is bordered to the north by agricultural land, to the east by upland hardwood forest and pasture, to the west by agricultural land and the Rocky River and to the south by SR 1312. Figure 13 shows existing land use and topography. Soils are mapped as the Wickham, Wahee and Georgeville series (Figure 14) (USDAa 0 k unpublished). Historically, the predominant plant community on the site was probably Dry- Mesic Oak-Hickory Forest. The mitigation site has been significantly altered from its historical community type by conversion to agricultural use. Figure 15 depicts the existing vegetative communities at MW-02. The proposed mitigation will fill 5.5 acres within the reservoir boundary. The fill material will be obtained from adjacent areas within the proposed reservoir (Figure 16). Final elevations within the mitigation site will vary between 540.6 and 541.3 feet MSL, with a maximum elevation of 1 foot above the proposed reservoir's normal pool (540.3 MSL). Site specific grading plans are provided in Figure 17. Hydrology will be provided by waters of the adjacent reservoir and existing hillside groundwater discharge. Ditches on the site will be blocked with impervious clay plugs (Figure 18). The mitigation site will be planted with native wetland plants. The target vegetative community is the Piedmont Alluvial Forest with areas of Floodplain Pool and emergent wetland. 23 Figure 12. Photograph of existing conditions at Mitigation Wetland-02, Chatham Cnnnty Nnrth Cnrnlins H:\SC9901-HW\800\LAND-USE.dwg, MW02 LAND-USE, 6/21/2005 8:46:13 AK dwft HPU5000.pd, 1:2.01693 n:? xvyui-nw ? auu ? r ¦ ¦ ANN N ` Q J m m C Z Z0 rn vv Q pOV Ov 000010 ptv z 0 w Z S v ° o ?p 7 v v ,y S vv-9O v ov a° v v ° pO o °? °pO v :I 1 I I ¦ 3 ¦ i i i i I p-.S_ f<n0N ZgA z M ;? ?oz a;3?e NA Z6?rr11 8 y Z Im A CD m9 M ym$ O ? S i9 O ¦ ¦ .1¦_ ¦ ¦ rim ¦ . _ N 9 z x m c CZ o ? a o? 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S June 6, 2005 Southern Pines, North Carolina Scale 1:2000 25 H:\SC99D1-HW\600\VegataWeCommunides.dwg, MW02 VegeComm, 6/21/2DD5 1:14:11 PM, dwilt, \\exchange\HPU5000, 1:2.01693 s' ?. .t r. /00000 r - z m °..°o v "v o v ° o °4v?/? ? i tp v° I JK I? \ ???W'a_° °v v v\ O 1 • • ¦ ¦ L • ¦ ' 'D S N • z O Ur A • 8[2z o ' 0 ¦ ¦ ¦ a ?r i 2 GG .r !9S z 11 ?o 'g -- v v v °vv p°vo° _ ° o a v yo2 mZ z N C z °-_ m B 'ab dd` 10 43 r? rnz ¦ AM Z13 C h o . 1 o m n 3 x ¦ • ? ? g A cn A ' - 9 [r?3 0 ¦ • °o e ROCKY RIVER LOWER RESERVOIR EXPANSION REVISIONS g FOR THE /? Hobbs Upchurch & Associates PA SYM. DESCRIPTION DATE er TOWN OF SILER CITY , , . Consulting Engineers q ` 1 j y c CHATHAM COUNTY, NORTH CAROLINA SDUMERM PINES, NC - CHARLDT/& NC l _? N m NAGS HEAD, NC - RVAIGH. NC I/YRRE BE I-f7G1.M1 l /'1 P ? r- N MITIGATION WETLAND-02 ACH. SC - DEALIFW. SC T E 300 S.W. Broad Street, Southern Pines, North Carolina 28367 EXISTING VEGETATIVE COMMUNI I S Phone: (910) 692-5616 - Fax: (910) 692-4795 O? 26 H:\SC9901-HW\800\BORROWAREAS.dwg, MW02 BORROW PITS, 6/20/2005 4:07:26 PM, dw1k \\exchange\HPU5000, 1:2.01693 - - --- - - - - -- - - - - - - ` nip 11 ?V1 __________ ____- - ; "\> \ \\ \ Furl Z£S - ------ - ------------- -' -- - -- \ \\\ - \\\\ - - - - - - - - - - - - - - N 9 ------ ---- -------------- -_ --M -- \ -S36_,\\\ N ~ --'l --------- L4:E -- \ \ C) 1-0 m I I ( w X m _ v)v o 1 1 / ( \ \ \ \\ 045 , \ \ \ ` \'\\\\\ \ \ \\ l 1 / - - \-----_-_ ?? --- -- -------- --- / Q / 1 //%/ / \\ \\\\ 1, Plk \OX / I \\ \ A I \\\ \ V \ \\ \ \ \\\ . v i 1 IA \\\\\\ \\\\\ ?1 \ \\ /'/ ------ ? \ \ \ - \ Cal) \ \\ ,\\ qk 0 -_---- O \I \ r \ \\ \ \\ / -, m ;0 C/) ? - ` \' \ \ I al 111 I\ -\\x \ p \ tJ _- - _--- 1 / / I \ \ \ 1 - ° Q - OX \ \ j \?\\ / z o \ \ -- I ? \ -\ --1 0\ \ 00 t ;0 m V) 0 1 1 1 1 \ ` \ 1 1 1 1 1 \ / \ 1 1 \ \\ \ 1 \ 1 / ? -,--- v i --- \\\\ \\ l i \ \ \ 1 1 1 1 1 ? ? /? 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DESCRIPTION DATE BY e B TOWN OF SILER CITY , , . . Consulting Engineers o N m CHATHAM COUNTY, NORTH CAROLINA SOUTHERN ARL NC NC ES, NC m HEA NC - RAL MYRTLE BEACH SC BEAUFORT SC PRELIMINARY N MITIGATION WETLAND-02 , - , BORROW AREAS #3 AND #4 300 S.W. Broad Street, Southern Pines, North Carolina 28387 Phone: (910) 692-5616 - Fax: (910) 692-4795 27 m m m m m m m m m m m m r m m m m m m H:\SC9901-HW\800\GRADING PLAN-MW 1&2.dwg, MW02 GRADING 100so1g, 6/21/2005 8:37:31 AM, dwin, \\exchange\HPU5000, 1:2.01693 ///o \ \I\1 \?\\`- ///I NDA 1 II I I`?1 ? /// l l ? I II ? I\ III (IIII 2 \ I III ?y / / F9 cq)!8 \\? 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I ?? \ II I\ I I I I 1 \ \ ? \1 ED C PP RD. - \ \ (I 1 537 32 533 I I I -\ \ I I n 1/ \ _- \ \ -\ A r? o X r?rrr?? T x 2 O 0 \ -i 0 0 " 51 -I O O O Z Z O O ° m z z0 O / v° m m m e c? vm - N Ui O O N ;0 O ? n n z z c ° 0 o N vn C C 8 8 'D Z1 C C O z 01 ;D A D O m N o 18 . c? N m Z C7 > 41 D ??gb ? dP11/J MOMS A-1 b ROCKY RIVER LOWER RESERVOIR EXPANSION K[VINUNb FOR THE Hobbs, Upchurch & Associates, P.A. ' SYM• DESCRIPTION DATE BY TOWN OF SILER CITY Consulting En ineers ` g c CHATHAM COUNTY, NORTH CAROLINA SOUTNERM PlNEx NC - f?gRMM NC N m NAGS HEAD, NC - RMEW, HC rf1GUMMf71 ° ci 0 0 MITIGATION WETLAND-02 MYRtLE BEACH, SC - MUFORT, SC N GRADING PLAN 300 S.W. Broad Street, Southern Pines, North Carolina 28387 Phone: (910) 692-5616 - Fax: (910) 692-4795 28 i i i i i C in 3^ 9 ' 3H 5H H _$ EXISTING F DITCH PROPOSED GRADE BOTTOM 5, ELEVATION 4:? 'CLAY DITCH PLUG 4' 1 VARIES T MATTING 12 MATERX SECTION A-A NTS IMPERVIOUS GRADE EXISTING CLAY DITCH DITCH PLUG i, IN 6' 6' 12• SECTION B-B NTS B IMPERVIOUS CLAY DITCH PLUG 5'd EXISTING y a. d: DITCH .d . dam, 9 DITCH s '? r -(j--WIDTH 4:1 elope d x'4:1 SlopeA _ VARIES C Q ? 61 A A B PLAN VIEW OF EXISTING DITCH WITH IMPERVIOUS CLAY DITCH PLUG NTS N Z 0 zu, Ix d a m V1 ? ' N (? V N N e ? z o i a . yQS v N N O C ? O fN = 8 z 0 ZN Q z O? % V Wa W X= cn U in5 5 fh 0 cc 0: U) W `05 3 UO U 0S V W j ? U 0 D: DAM JUNE, 2005 PENN= BGL OR'Aft DFW OOM®: BGL Soo AS SHOWN ran ". 18 29 The forest community will be created by planting woody hydrophytic species such as river birch, sycamore, hackberry, green ash and tulip poplar. Herbaceous species such as soft rush, woolgrass and sedges will colonize the pool and marsh communities. Saplings will be planted using 10x10 foot spacing (or less), with at least 435 trees per acre, and will be fertilized in their first and second years. Off-site Wetland Mitigation The 9.08 acre Randolph County property purchased by the Town will provide wetland preservation and enhancement. Wetland preservation and enhancement along this part of the Rocky River may help improve water quality downstream. Table 6 lists the proposed off-site wetland mitigation activities. A detailed discussion of these activities follows. Table 6. Proposed off-site wetland mitigation for the Rocky River Lower Reservoir expansion project, Chatham County, North Carolina. Proposed Wetland Mitigation Mitigation Mitigation to Mitigation Acreage Activity Acreage Impact Ratio Credit Wetland Enhancement - Randolph 3.23 4:1 0.81 Count Wetland Preservation - Randolph 0.30 10:1 0.03 Count Total 3.53 0.84 Randolph County Mitigation Site ' The Randolph County mitigation site (Parcel No. 8735049459) is located 2 miles south of Liberty at ' the intersection of US Highway 421 and NC Highway 49 along the Rocky River near the Chatham-Randolph ' County line. (Figure 3 and 19). The proposed wetland enhancement and preservation involves 3.53 acres of ' the 9.08 acre tract. The tract is bordered to the north by open wetland, to the south by pasture, to the east by ' hardwood forest and to the west by US Highway 421 (Figure 20). 30 Figure 20: Photograph of existing conditions at the mitigation site in Randolph County, N C V j j \` + ,7411i{ - ?j1,?? . ? Ci m .4TSi 11 11 of 's? yam. IL { ALA (k AT" j? ? - J - - i Figure 19. General location of the off-site mitigation property in Randolph County (Parcel No. 8735049459), North Carolina, Rocky River Lower Reservoir expansion project, Chatham County, North Carolina. Prepared By: Site Location Q Dr. J.H. Carter III & Associates, Inc. June 6, 2005 Southern Pines, North Carolina 31 Soils on the mitigation site are mapped as the Wehadkee and Vance series (Figure 21) (USDA(a) unpublished). Historically, plant communities probably included Mesic Mixed Hardwood Forest and Piedmont Alluvial Forest. These communities have been altered by fire and beaver (Castor canadensis) activity that have allowed exotic plant species to invade. As shown in Figure 20, this site is currently dominated by hydrophytic vegetation including vermin grass, Japanese honeysuckle (Lonicera japonica), tearthumb (Polygonum sagittatum), soft rush, blackberry (Rubus sp.), black willow (Salix nigra) and sweetgum saplings. Remnants of the native community types exist along the edges of the wetland. Figure 3 shows the existing vegetative communities on the property. The entire 9.08 acre property, including 3.53 acres of jurisdictional wetlands, will be preserved in perpetuity through the deed restrictions. Of the jurisdictional wetlands acreage, 3.23 acres are non-forested and will be enhanced by planting river birch, black willow, green ash and tulip poplar (a minimum of 435 trees per acre). OTHER ACTIVITIES Fringe Wetlands Many of the wetlands to be impacted by the proposed project are narrow fringe wetlands around the existing reservoir. Fringe wetlands protect water quality, protect and stabilize shorelines and provide habitat for fish and wildlife. Based on topography and landscape position, it is anticipated that wetland fringe will naturally form around portions of the new reservoir just as is has formed around the existing reservoir. Approximately 3.5 acres of fringe wetlands are projected to develop that will be similar to those impacted. Wetland Preservation/Enhancement within 100-foot Reservoir Buffer Existing wetlands within the proposed 100-foot buffer will be preserved in perpetuity L through deed restrictions. The 100-foot wide buffer surrounding the reservoir will prevent any future activities from impacting wetlands therein. The preservation of forested wetlands (0.15 acres) and enhancement (revegetation) of nonforested wetlands (0.16 acres) within the 100-foot buffer are not included as mitigation. These measures are expected to enhance water quality and wildlife habitat. 32 ? r WIA 7 "h 6G '+,. Zr gfn 2pE2 { 2oB2 a ? i ?, z f yF',; :LC'e?z 8A=Wahadkee loam, poorly drained 57C=Vane sandy loam, 8-15 /o slopes Figure 21. Soil map for the Randolph County mitigation property (Parcel No. 8735049459), North Carolina, Rocky River Lower Reservoir expansion project, Chatham County, North Carolina Site Location June 6, 2005 Prepared By: Dr. J.H. Carter, III & Associates, Inc. 33 Stream Enhancement within the 100-foot Reservoir Buffer Approximately 225 linear feet of non-forested streams within the proposed reservoir's 100-foot buffer will be revegetated with river birch, tulip poplar, green ash and sycamore as part of the management of the 100-foot buffer. This enhancement activity will not generate mitigation credits for the project. The locations of these streams are shown in Figure 22. Stream Preservation within the 100-foot Reservoir Buffer Approximately 324 linear feet of forested stream channel within the reservoir's 100-foot buffer will be preserved. This preservation activity will not generate mitigation credits for the project. The locations of these streams are shown in Figure 22. Replanting uplands within the 100-foot Reservoir Buffer Approximately 35 acres of uplands within the proposed 100-foot buffer are currently being used as pasture or cropland. These areas will be plowed and disked and replanted with appropriate upland tree and shrub species. OTHER INFORMATION 100-foot Buffer Encroachments There are several existing structures in areas that are part of the proposed reservoir pool I n E r or its 100-foot buffer. These structures include powerline easements, roads, a building and a small dam. Each of these encroachments existed within the footprint of the proposed reservoir and/or within the proposed 100-foot buffer prior to development of the reservoir plan. Each of the encroachments presents an exception to the 100-foot vegetated buffer. Some of these encroachments are unvegetated and others have vegetation within them that is manipulated as part of their use. Following are descriptions of each encroachment and its current and proposed vegetative condition (Figures 23a and 23b). 1) Electric transmission line easements: These electric transmission lines cross the reservoir and its 100-foot buffer (Figure 23a and 23b). These lines are operated and maintained by Progress Energy. All of the transmission line encroachments are in the central portion of the reservoir and 2 of the 3 encroachments are perpendicular crossings of the reservoir. The 34 1 Enhancement - - -- - -- - -- - -- - - -- - -- - -- - -- - --- Preservation -------------------- i -----------------•-- 1 - - - --- I --------------- ---------------- ---------------- ---------------- ---------------- ---------------- --------------- Preservation Enhancement Preservation I Legend Stream r Perennial Streams Intermittent Streams - Ephemeral ® Existing Proposed Reservoir Boundary ® Cropland Forest Pasture 100 foot buffer Figure 22. Location of on-site stream channel enhancement and preservation within the 100-foot buffer. Rocky River Lower Reservoir expansion project, Chatham County, North Carolina. N Prepared By: W E 0 75 150 300 Feet Dr. J.H. Carter III & Associates, Inc. I I I I I I I I Southern Pines, North Carolina June 6. 2005 S 35 ¦ Match Line Figure 23a ClC, l inch = 880 meters Figure N 14 J 2005 une Prepared by: Dr. J.H. Carter III & Associates, Inc. Proposed 100-foot buffer Proposed normal pool Existing Rocky River 23b. Encroachments within the 100-foot buffer of the Rocky River Lower Reservoir expansion project, Chatham County, North Carolina. 37 remaining encroachment runs parallel to the reservoir as it gradually crosses the reservoir from north to south (northwest by southeast). The Town is in the process of negotiating with Progress Energy for the removal or relocation of transmission line poles from the proposed reservoir pool and the 100-foot buffer. The transmission line rights-of-way will continue to exist as spanned crossings of the reservoir and its 100-foot buffer, Herbaceous vegetation, shrubs and small trees currently exist in the power line rights-of- way and will continue to exist after the completion of the reservoir project. Progress Energy mows the vegetation to prevent trees from growing large enough to interfere with the overhead utility lines and to keep shrubs from becoming so dense that maintenance access to the utility lines is difficult. There is, however, sufficient vegetation present within right-of-way to prevent erosion, slow stormwater flows and capture sediments from surface runoff. 2) Roads - There are 2 types of road encroachments; private access roads and State roads. There is currently 1 private access road and 2 State roads that encroach upon the proposed reservoir and its 100-foot buffer. The private access road is on the western side of the reservoir approximately in the center of the site. The access road currently crosses a portion of the proposed reservoir and its 100-foot buffer that protrudes to the west. This crossing will be moved outside of the reservoir and its 100-foot buffer and will no longer be an encroachment. The area of the current road within the buffer will be revegetated. The remaining portion of the existing access road will be flooded by the proposed pool. State Route 1355 crosses the reservoir in the northernmost portion of the site and SR 1312 crosses the middle portion of the reservoir. Both road crossings are perpendicular to the reservoir and will be left in place and maintained by the NC Department of Transportation NCDOT). Both crossings are impervious surfaces of asphalt and concrete which are void of vegetation. The existing bridges will not be altered as a result of this project. 3) Buildings - One building exists within the project boundary. It is a small cabin on the western side of the reservoir. It is not located within the proposed pool area, however, it is within the 100-foot buffer. The cabin will remain in place and an area totaling 0.12 acre will be 38 excluded from the 100-foot buffer. A 30 foot wide buffer will exist between the cabin and the expanded reservoir. 4) Clapp Lake Dam - Clapp Lake is a small, man-made lake located in the south-central portion of the project site on the western side of the proposed reservoir. The lake's dam is located less than 100 feet from the proposed reservoir pool; the lake itself is outside the project boundary. The buffer around the expanded reservoir will not be 100 feet in this area, but will extend to the toe of the slope of the dam. The Town currently holds a 99- year lease on the lake and the dam. The dam must be kept free of debris and vegetation for safety and function, and thus will be excluded from the 100-foot buffer. MONITORING ACTIVITIES Reference Forest Ecosystem A reference forest ecosystem (RFE) has been located for MW-01 and MW-02. The site is located on Fox Lake adjacent to the Rocky River Lower Reservoir and is owned by the Town (Figure 24). The vegetative community of this site is Piedmont Alluvial Forest. JCA is in the process of characterizing the RFE and will install 1 10x10 meter vegetation monitoring plot and 1 groundwater monitoring well (1) in conjunction with the establishment of the monitoring plots and wells within the on-site mitigation plots. On-site Wetland Mitigation Sites Both wetland mitigation sites will be monitored for a period of 5 years or until the C success criteria have been met (see below), whichever is longer. Within MW-01 and MW-02, monitoring wells will be placed in the areas of highest elevation on the site to ensure hydrologic success criteria are being met throughout the site. As shown in Figures 25 and 26, 9 monitoring wells will be placed in MW-01 and 5 monitoring wells will be placed in MW-02. Electronic monitoring wells will record water levels daily and be downloaded every 2-3 months. At each mitigation site, vegetation will be characterized by species, prevalence and percent cover each year during the 5-year (or longer) monitoring period. Eight 10x10 meter vegetation plots will be established at MW-O1 with 5 10x10 meter vegetation plots at MW-02 39 reatme,ntSPla ` Figure 24. Location of Reference Forest Ecosystem (RFE) at Fox Lake for the Rocky River Lower Reservoir wetland mitigation sites, Chatham County, North Carolina. 40 H:\SC9901-HW\800\M0N1T0PJNG.dwg, MW01 1DDscale, 6121/2005 8:31:17 AM, dwik, \\exchange\HPU5DD0, 1:2.01693 SC9901-HW ?00 D Z S N rrssrr 8 y Z o m 0 2 120scale \ DFW =0 r/1 -120' (11x1 n 6 90 0 v M r. ?v v i r• 2 c cn r z y v 1 1 ?x 1 D?D qm i r If fV U7 0 z W O W z r1 o rr 0 90 10 ? ua x sF3 ? n . a ? S 0 IL ROCKY RIVER LOWER RESERVOIR EXPANSION FOR THE , TOWN OF SILER CITY CHATHAM COUNTY. NORTH CAROLINA MITIGATION WETLAND-01 MONITORING PLAN a- I 1 ;r 1 0?I II I AA 1 0 z I I / / / / / / / 1 / 1 1 1 / 1 / 1 1 1 1 ' O O ? O A A ? z? P9 I Hobbs, Upchurch & Associates, P.A. Consulting Engineers 1qj SOWINIM PINES, NC - CH01KOM NC NAGS HEAD, NC - RALEIGH, NC IMRLE BEACM SC - BEWFDRT, SC 300 S.W. Broad Street, Southern Pines, North Carolina 28387 Phone: (910) 692-5616 - Fax: (910) 692-4795 0 ? -I i ?o o 0o o °o_ ?o r ?0 0 Do 0 ° m zo m Z m O 0 2? I 3 D U A Z >0 z 0 xo o x o mn o r- 'v z o z r- m w 0 41 H:\SC9901-HW\8D0\MONITORING.dwg, MW02 100901e, 621/2005 8:28:01 AM, dwik \\exchange\HPUSOOO, 1:2.01693 SC9901-HW \ 800 \ MONITONINOAw9 \ mwu[ ivuscaie - - 0 401 Y 3 t.7. P N CCO? O (?/f 0 Z8 dd ?J F -w- 0 ?? p Q m!A rri Z U) ? ZZ U) O a r ? W r 0 P ? ?? C?3 ED CLAPP RD. 131 \ •. 22 ? `'' ? m0 ` 0 o ? u z Ti o n o n a r [ ?l O 8 0 ? , I 1 0 O OO 0 O ?0 ?- D ' D 0 0 0 O 1/1 1n D N R1 C O N 0 zo o zm° ? t o m° m o ?3 m 0 N z v O Z D O 1 L. O xC) O x ->i 1-1 m_ O O Z u+ rD- m w 0 F) `" n m z D O Ar ?b ROCKY RIVER LOWER RESERVOIR EXPANSION REVISIONS FOR THE Hobbs Upchurch & Associates PA. ' SYM. DESCRIPTION DESCRIPTION DATE' BY TOWN OF SILER CITY , , Consulting Engineers `c CHATHAM COUNTY NORTH CAROLINA , SOWHERN PINES, NC _ CK4RLOtt& NC N m NAGS HEAD, NC - RALEIGH, NC MYRTLE BEACH SC - BEAUFOR SO ?? T V? = 0 ? 0 N MITIGATION WETLAND-02 , r. Z MONITORING PLAN 300 S.W. Broad Street, Southern Pines, North Carolina 28387 Phone: (910) 692-5616 - Fax: (910) 692-4795 0 42 (Figures 25 and 26). Vegetation monitoring will occur in late summer or early fall before leaf drop. Tree sapling survival will be monitored each year. All mitigation sites will be transected annually and dead saplings will be replaced during the 5-year monitoring period or until the success criteria are met. Soil samples will be taken when monitoring begins and each year thereafter and examined for hydric soil and wetland hydrology characteristics. Off-site Wetland Mitigation in Randolph County Tree sapling survival within the Randolph County wetland enhancement area (3.23 acres) will be monitored every year. The site will be transected annually and dead saplings will be replaced during the 5-year or longer monitoring period. Off-site Stream Preservation in Randolph County Approximately 2,660 linear feet of stream channel will be preserved on the Randolph I 1 F County property. Stream channel characteristics and/or stability will be checked annually. Wetland and Stream Channel Enhancement and Preservation within the 100-foot Reservoir Buffer Although these activities will not generate mitigation credits for the project, the sites will be monitored for 5 years. All enhancement areas will be transected annually and dead saplings will be replaced during the 5-year monitoring period. SUCCESS CRITERIA Wetland Hydrology The success criteria for wetland hydrology will be met when hydrology in the restored/created wetlands meet the minimum criteria as specified in the 1987 ACOE Wetland Delineation Manual (ACOE 1987) for a jurisdictional wetland. Criteria for wetland hydrology are met when the areas are inundated or saturated within 12 inches of the surface continuously for at least 12 percent of the growing season (approximately 32 days) under normal rainfall. Under drought conditions (as designated by the NC Drought Monitoring Council), the sites must 43 be inundated or saturated within 12 inches of the surface continuously for at least 5 percent of the growing season (approximately 13 days). The growing season for Chatham County runs from early March to late November (approximately 265 days). In general, success will emphasize establishment of wetland hydrology similar to that present in the RFE. Soil samples will be collected and characterized when monitoring begins and each year thereafter. Hydric soil and wetland hydrology characteristics will be documented. Hydric Soils Hydric soils indicators include the presence of organic soils, histic epipedons, sulfidic material, an aquic or peraquic moisture regime, direct evidence of reducing conditions, gleyed, low chroma and low chroma/mottled soils, and iron and manganese concretions. Appropriate soil characteristics will be compared to hydric soils present with the RFE. Depending on soil type and structure, site hydrology with the mitigation area and rainfall, hydric soil characteristics may or may not be met in a specific area during the monitoring period. If the desired wetland hydrology criteria are met, but hydric soil characteristics are not yet evident, the future formation of hydric soils will be assumed. Wetland Vegetation and Survival Success criteria for vegetation will be met when at least 260 trees/acre of the approved C t planted species have survived for at least 5 years on at least 23.35 acres. Volunteers of desirable species will be counted towards the 260 trees/acre. Herbaceous vegetation such as soft rush and sedges are expected to naturally revegetate the mitigation sites. In general, success will emphasize establishment of hydrophytic vegetation similar to that present in the RFE. The final living numbers for planted species may deviate 10 percent from the initial planted numbers for 75 percent of the planted species and still be considered successful. The remaining 25 percent of planted species may deviate more than 10 percent and still be considered successful. 44 REPORTING Wetland Mitigation Sites An as-built report will be submitted to the ACOE and DWQ after the mitigation sites are constructed. The as-built report will include final elevations, a map of planted trees/shrubs including location and number planted, vegetation sample plot and monitoring well locations and photographic reference points. An annual report will be submitted to the ACOE and DWQ by 31 January of each year I during the 5-year (or longer) monitoring period. Annual reports will include a plot of the groundwater elevations in the mitigation sites and reference area, vegetation plot and water level monitoring data and photographs of each monitoring plot. Results of the annual site pedestrian surveys will be reported. All data collected during the monitoring period will be summarized and the acreage of successful and unsuccessful mitigation will be documented. Stream Mitigation Sites Information from the Randolph County stream channel preservation site will be reported in the annual report for the 5-year (or longer) monitoring period. Annual reports will include photographs of representative sections of stream channel and information on coverage and survival of planted and natural vegetation. CONTINGENCY PLANS All aspects of the mitigation plan will be closely monitored throughout the 5-year (or longer) monitoring period and management actions or site adjustments will be made to ensure success. Volunteers of undesirable or exotic plant species and/or animal damage may affect the survival and growth of planted trees in the mitigation sites. As needed, undesirable or exotic species will be control of manually, mechanically or with herbicides. Relevant State and Federal regulations will be followed if herbicides are used. Depredation of planted vegetation by animals will be monitored. Depending on the species, protective measures may include controlling water levels, direct control of animals (trapping or shooting) and/or using predator guards on seedlings. 45 ' Other adjustments could include planting the same or additional hydrophytic species, modifications to hydrology sources to increase or decrease hydroperiods and soil saturation/ inundation, regrading of specific areas and other actions. ' If during the monitoring period, a site(s) appears to be failing or unsuccessful after adjustments have been made, the Town will consult the ACOE and DWQ. 46 REFERENCES I Dr. J.H. Carter III and Associates. 2004. Draft Wetland and Stream Channel Mitigation Plan for the Rocky River Lower Reservoir Expansion, Chatham County, North Carolina. Report prepared for the U.S. Army Corps of Engineers and North Carolina Division of Water Quality. 43 pp. North Carolina Department of Environment and Natural Resources, Division of Water Quality, Water Quality Section-Planning Branch. 2003. North Carolina Water Quality Assessment and Impaired Waters List (2002 Integrated 305b and 303d Report). Raleigh, North Carolina. Schafale, M.P. and A.S. Weakley. 1990. Classification of the natural communities of North Carolina, third approximation. North Carolina Natural Heritage Program, Raleigh, North Carolina. U S Army Corps of Engineers. 1987. Corps of Engineers wetland delineation manual, Technical Report Y-87-1, U.S. Army Engineer Waterways Experiment Station, Vicksburg, MS. U S Army Corps of Engineers. 2002. Regulatory Guidance Letter. Guidance on Compensatory Mitigation Projects. No. 02-2. U S Department of Agriculture, Natural Resources Conservation Service (a). Unpublished Soil Survey for Randolph County, North Carolina. U S Department of Agriculture, Natural Resources Conservation Service (b). Unpublished Soil Survey for Chatham County, North Carolina. 47