The URL can be used to link to this page

Home My WebLink About20140333 Ver 1_RFP Techncial Proposal_20140404Part 5 - Technical A h PR 4 2014 a--p I / P aoly o The Holman Mill Stream Mitigation Site (Site) is located in Alamance County approximately 4 miles southeast of Snow Camp, INC (Figure i). The project involves restoration, enhancement, and preservation of Piedmont streams. The project is located within the EEP targeted watershed for the Cape Fear River Basin Hydrologic Unit Code (HUC) 0303000205005o and NCDWQ Subbasin 03 -06 -04 and is being submitted for mitigation credit in the Cape Fear River Basin HUC 03030002. The proposed project is located in the Cane Creek targeted local watershed (TLW) (03030002050050) which flows into Cane Creek and eventually into the Haw River. The 2oo9 Cape Fear RBRP (River Basin Restoration Priorities) indicates that EEP has completed or is in the process of completing numerous projects within the Cane Creek TLW. Implementation of the Holman Mill Mitigation project will add to the body of work already in place in this sub -basin with the goal of more comprehensive watershed based water quality improvements. Rules for the B. Everett Jordan Lake watershed seek significant nutrient reductions within the basin. The Site provides an opportunity to remove cattle from creeks, restore riparian buffers, and decrease sediment inputs within the basin, all of which support the nutrient reduction goals. The Site fully supports the Cataloging Unit (CU) -wide functional objectives stated in the RFP to reduce and control both nutrient and sediment inputs in the Cape Fear River Basin HUC 03030002. This project will reduce sediment and nutrient loading, provide and improve instream habitats, provide and improve terrestrial (riparian) habitats, improve stream stability, and improve hydrologic function. The areas surrounding the streams proposed for restoration and enhancement are used for cattle pasture and field crops. The Site will provide nutrient reduction by creating a buffer between cattle operations and the creeks. Reconnection of these creeks to their historic floodplain will filter nutrients and cattle waste before runoff flows into Pine Hill Branch, the mainstem preservation reach, and ultimately the Haw River. Sources: NC -EEP. 2009. Cape Fear River Basin Restoration Priorities. NC -DWQ. 2005. Cape Fear River Basinwide Water Quality Plan. North Carolina Wildlife Resources Commission. 2005. North Carolina Wildlife Action Plan. Raleigh, NC. 5.1 Project Goals and Objectives The major goals of the proposed stream mitigation project are to provide ecological and water quality enhancements to the Cape Fear River Basin while creating a functional riparian corridor at the site level, providing floodplain habitat and ecological function, and restoring a Piedmont Bottomland Forest community as described by Schafale and Weakley (1990). Specific enhancements to water quality and ecological processes are outlined below in Table 5.1. Wildlands Engineering, Inc. Page 5.1 Holman Mill Stream Mitigation Site — Part 5 r,.►,►,. - . nnrl Wntor Owility r.nniq of the Mitigation Pfolect Water Quality Goals Reduce and control Sediment input from unprotected and eroding stream banks will be reduced by sediment inputs and installing bioengineering and in- stream structures while creating a stable channel improve stream stability form using geomorphic design principles. Sediment from off -site sources will be (RFP Goal) captured by deposition on restored floodplain areas where native vegetation will slow overland flow velocities. Cattle will be removed eliminating bank trampling. Reduce and manage Nutrient inputs from adjacent cattle pastures will be absorbed on -site by filtering nutrient inputs (RFP Goal) runoff and flood flows through restored floodplain areas and wetlands. Flood flows can disperse through native vegetation and be captured in adjacent wetlands. Increased surface water residency time will provide contact treatment time and groundwater recharge potential. Improve hydrologic Restored bed form and installation of woody structures will promote re- aeration function through a and will allow for oxygen levels to be maintained in the perennial reaches. decrease in water Restoring stream and floodplain interaction will improve hydrologic function. temperature and increase Creation of pool zones will lower temperature, helping to maintain dissolved in dissolved oxygen oxygen concentrations. Establishment and maintenance of riparian buffers will concentrations create long-term shading of the channel flow to minimize thermal heating. Ecological Goals Provide and improve Adjacent buffer areas will be restored by planting native vegetation. These areas terrestrial habitat will receive more regular inundating flows. A native natural community will be established that connects with other forested areas. Within the project limits, the floodplain area along each reach will be placed under a conservation easement. A minimum 50-foot wooded riparian buffer will be established off the top of bank of each project reach. Provide and improve A stable channel form and structure appropriate for Piedmont channels will be instream habitat constructed. Introduction of large woody debris, root wads, brush toe meander bends, and native stream bank vegetation will substantially increase habitat value. Decrease channel velocities By allowing for more overbank flooding and by increasing channel roughness, local channel velocities can be reduced. This velocity reduction will allow for lower bank shear stress, formation of refuge zones during large storm events and zonal sorting of depositional material. 5.2 Project Description The following section describes the existing conditions at the Site in terms of geomorphic condition, watershed, soils, geology, cultural resources, species of concern, regulated floodplain zones, and site constraints. Cross sectional surveys were conducted on all reaches proposed for restoration on the project. Cross section details are shown in Appendix B. 5.2.3. Existing Site Conditions The Site is an active cattle farm with fields used for grazing throughout the project area, immediately downslope from active farming of field crops. The streams are actively used as the water source for cattle on the property. The proposed stream restoration project includes preservation on Pine Hill Branch and restoration or enhancement on four unnamed tributaries to Pine Hill Branch, UT1, UTz, UTza, and UTzb, as illustrated on Figure 2. Pine Hill Branch, the largest stream on the project site flows north along the eastern site boundary. UT1 flows east and joins with Pine Hill Branch. UTz flows east along the north side of the property and joins Pine Hill Branch. UTza flows generally southeast and joins UTz. UTzb begins below an existing farm pond and flows generally northeast joining UTz. Wildlands Engineering, Inc. Page 5.2 Holman Mill Stream Mitigation Site — Part 5 5.2.2 Existing Conditions - Streams Pine Hill Branch UTi, UT2, UT2a, and Pine Hill Branch were identified as perennial streams on October 11, 2013, using the North Carolina Division of Water Quality (NCDWQ) Stream Identification Forms. UT2b was identified as an intermittent stream. Copies of these forms are included in Appendix B. The streams are depicted on Figure 2. Details about the existing streams are provided in Section 5.2.2, below. Pine Hill Branch enters the Site at the southern property boundary along Clark Road and flows north until it leaves the Site at the northeast corner of the site. Cattle are currently fenced out from accessing the stream, leaving it in relatively stable condition throughout the reach. In- stream cobble from several small remnant mill dams have contributed to variability in channel pattern and cross - section dimension along the length of stream. Pine Hill Branch has a mature forested buffer that appears to be over loo feet wide on the right bank. The forested buffer along the left bank is over 5o feet wide upstream of UT1 but fluctuates at or below 50 feet between UT1 and UT2. Canopy species include river birch (Betula nigra), sweetgum (Liquidambar styraciflua), sycamore (Platanus occidentalis), shagbark hickory (Carya ovata), and white oak (Quercus alba). Understory species include American elm (Ulmus americana), coralberry (Symphoricarpos orbiculatus), winged elm (Ulmus alata), ironwood (Carpinus caroliniana), northern spicebush (Lindera benzoin), and some Chinese privet (Ligustrum sinense) (minor). Herbaceous species include christmas fern (Polystichum acrostichoides), soft rush (luncus effusus), aster (Erigeron spp.), Japanese honeysuckle (Lonicera japonica), and Nepalese browntop (Microstegium vimineum). :x L Wildlands Engineering, Inc. Page 5.3 Holman Mill Stream Mitigation Site — Part 5 Eli :x L Wildlands Engineering, Inc. Page 5.3 Holman Mill Stream Mitigation Site — Part 5 UT, UT1 enters the Site at the west property boundary along Holman Mill Road and flows east to Pine Hill Branch. UTs has been heavily trampled by cattle, leaving actively eroding stream banks and variability in cross - section along the reach. Channel incision ranges from slight to moderate throughout the reach. Based on cross sectional survey data, UT1 classifies as a Rosgen Eyb stream though several areas are heavily wallowed out by cattle making classification difficult. Mature trees are sparsely scattered along the top of bank along UT1. Tree species include American elm, black willow (5alix nigra), and willow oak (Quercus nigra). Coralberry, which is a shrub, is scattered along portions of the pasture. The majority of vegetation is pasture grasses (likely Festuca spp.). Other herbaceous species include blackberry UT2 (Rubus spp.), rough cocklebur (Xanthium strumarium), horsenettle (Solanum carolinense), and wingstem (Verbesian altemifolia). A reachwide pebble count, pavement/subpavement samples, and cross sectional surveys were conducted on UT1. Data is provided in Appendix B and cross section locations are shown on Figure 2. UT2 enters the site at the northern property line and runs due east until its confluence with Pine Hill Branch. UT2 is divided in two reaches. Reach 1 of UT2 is forested within the floodplain area with boulder and cobble bed material in the stream. This section of UT2 shows areas of erosion from frequent cattle crossing, but in- stream bedrock provides grade control and the stream remains in fairly stable condition. Canopy species in these areas include green ash (Fraxinus pennsylvanica), shagbark hickory, sweetgum, and white oak. Understory was sparse with coralberry, Eastern red cedar (Juniperus virginiana) and American holly (Ilex opaca). Herbaceous species were present but not A, A" dense likely due to grazing. rY ,, Species include wingstem, Nepalese browntop, Pennsylvania N smartweed (Polygonum pennsylvanicum), and an unknown mint species. Reach 2 of UT2 begins below a bedrock knick point. Belowthis point, UT2 pushes up against the right edge of the valley with a wooded buffer present along the right bank for a portion of UT2 and the left opening up to a wide pasture area between UT2 andUT2a. The stream is deeply incised (BHR = 1.5 -3.1) with cattle having free access to the stream. Based on the survey data, the lower portion of UT2 classifies as an incised Rosgen E5 transitioning to a G5 stream with a bimodal sediment distribution. As the buffer opens to pasture, a few black willows, winged elms, sweetgum, and ` Wildlands Engineering, Inc. Page 5 4 Holman Mill Stream Mitigation Site — Part 5 sugarberry (Celtis laevigata) are scattered along the top of bank. Coralberry is present in clusters within the pasture. Herbaceous species include fescue, wingstem, cocklebur, blackberry, horsenettle, and unknown mint. A reachwide pebble count, pavement /subpavement samples, and cross sectional surveys were conducted on Reach 2 of UT2. Data is provided in Appendix B and cross section locations are shown on Figure 2. UT2a UT2a enters the site at the northern property line and runs southeast until its confluence with UT2, just upstream of Pine Hill Branch. UT2a is incised and serves as a water source for cattle. Trampled banks and cattle crossings are frequent along the length of stream. There is little vegetated buffer present with open pasture on both left and right floodplain areas. A few black willows, winged elms, sweetgum, and sugarberry (Celtis laevigata) are scattered along the top of bank. Coralberry is present in clusters within the pasture. Herbaceous species include fescue, wingstem, cocklebur, blackberry, horsenettle, and unknown mint. UT2a most nearly classifies as a Rosgen G4 channel type. A reachwide pebble count, pavement /subpavement samples, and cross sectional surveys were conducted on UT2a. Data is provided in Appendix B and cross section locations are shown on Figure 2. UT2b UT2b begins below an existing farm pond in the northeast corner of the project. UT2b flows northeast until its confluence with UT2. UT2b ranges from stable to slightly incised along the length of the reach. Frequent cattle crossings have eroded portions of the stream banks with little woody vegetation to keep them in place. UT2b is located within active cattle pasture. Although some woody vegetation exists along the stream banks, there are no areas where the buffer is greater than one tree in width and the buffer is highly discontinuous in a longitudinal manner along the creek. Mature trees including sweetgum, black willow, and American elm only along portions of the channel. The majority of vegetation is pasture grasses, coralberry, wingstem, blackberry, and dogfennel (Eupatorium capillifolium). Facultative wetland (FACW) and obligate (OBL) wetland plants present within the channel of UT2b include Pennsylvania smartweed, soft rush, ludwigia species, and spikerush (Eleocharis sp.). 5.2.3 Watershed Characterization The Site is located with the Targeted Local Watershed 03030002o5oo5o and NCDWQ Subbasin o3 -o6- 04. All onsite tributaries drain to Pine Hill Branch which is classified as Class C waters by NCDWQ. Topography, as indicated on the Crutchfield Crossroads USGS 7.5 minute topographic quadrangle, shows moderately sloped and steep areas, as well as low slope floodplain areas along Pine Hill Branch (Figure 3). Wildlands Engineering, Inc. Page 5.5 Holman Mill Stream Mitigation Site — Part 5 Drainage areas forth e project reaches were determined by delineating watersheds using z -foot contour intervals derived from Light Detection And Ranging (LiDAR) data obtained from the North Carolina Floodplain Mapping Program. Figure 4 shows the watershed boundaries for the Site. Land uses draining to the project reaches are primarily grass /herbaceous, forested, and residential. The watershed areas and current land use are summarized in Table 5.2, below. Table 5.2 Drainage Areas and Associated Land Use Reach Name Existing NCDWQ Intermittent Watershed Predominant Land Use Herndon Silt Loam Reach Stream / Perennial Area Alluvial land soil component is found on floodplains. They Len th (LF) Scores Status (acres) or ponded, but has a seasonal zone of water saturation at 6 inches. Georgeville soils are found on uplands and hillslopes on 49% forested, 42% cultivated, Pine Hill Branch 3,646 44.5 Perennial 1,077 3% impervious, 3% pasture, z% residential 59% cultivated crops; 37% UT1 2,550 30.5, 33.5 Perennial 102 forested; 2% impervious; 1% residential; 1 % open water 37% forested, 33% cultivated, UTz 1,300 35.0 Perennial 130 27% pasture, z% impervious, 1% open water 450/0 pasture, 32 %forested, z0% cultivated crops; z% UTza 350 36.75 Perennial 49 impervious surface; 1% residential 55% pasture, 40% cultivated UTzb 475 26.5 Intermittent 18 crops; 5 %open water Note: Reach lengths were determined based on GIS stream lengths and field observation of smuusiiy. 5.2.4 Soils The floodplain areas of the proposed project are mapped by the Alamance County Soil Survey. Soils in the project area floodplain are mapped as Herndon Silt loam, Local Alluvial Land, Georgeville Silt loam, and Goldston Channery Silt Loam. These soils are described below in Table 5.3. A soils map is provided in Figure S. Table 5.3 Project Soil Types and Descriptions Soil Name Description Herndon silt loam soils consist of very deep, well drained soils. They are typically found in gently sloping to Herndon Silt Loam moderately steep Piedmont uplands. These soils are rarely flooded. Alluvial land soil component is found on floodplains. They are poorly- drained soils consisting of loamy alluvium derived Local Alluvial Land from igneous and metamorphic rock. This soil is not flooded or ponded, but has a seasonal zone of water saturation at 6 inches. Georgeville soils are found on uplands and hillslopes on ridges. They are well- drained with low shrink -swell potential Georgeville Silt Loam and moderately high permeability. This soil unit is not typically flooded or ponded. Wildlands Engineering, Inc. Page 5.6 Holman Mill Stream Mitigation Site — Part 5 Soil Name Description Goldston channery silt loam soils consist of very deep, well Goldston Channery Silt drained soils. They are typically found in gently sloping to Loam moderately steep Piedmont uplands. These soils are rarely flooded. Source: Alamance County Soil Survey, USDA -NRCS, http: / /efotg.nres.usda.gov 5.2.5 Geology The Site is located in the Carolina Slate Belt of the Piedmont physiographic province. The Piedmont is characterized by gently rolling, well- rounded hills with long low ridges, with elevations ranging from 300 to 15oo feet above sea level. The Carolina Slate Belt consists of heated and deformed volcanic and sedimentary rocks. Approximately 55o to 65o million years ago, this region was the site of a series of oceanic volcanic islands. The underlying geology of the proposed restoration site is mapped as late Proterozoic to Cambrian age (goo to Soo million years in age) felsic metavolcanic rock (CZfv). This unit is described as light gray to greenish, metamorphosed dacitic to rhyolitic flows and tuffs interbedded with mafic and intermediate metavolcanic rock, meta - argillite and metamudstone. Shallow bedrock was observed on site and taken into account in the proposed design. The bedrock will not limit the ability to achieve the design approach. Sources: http: / /www. geology. enr .state.nc.us /usgs /carolina.htm http: / /www.geology.enr.state.nc.us/ Mineral% 2oresources /mineralresources.htmI 5.2.6 Cultural Resources The site is not located near any sites listed on the National Register with the State Historic Preservation Office (SHPO). The archaeological site files at the North Carolina Office of State Archaeology (OSA) have not been reviewed at this time. All appropriate cultural resource agencies will be contacted for their review and comment prior to any land disturbing activity. 5.2.7 Threatened and Endangered Species The US Fish and Wildlife Service (USFWS) and NC Natural Heritage Program (NHP) databases were AlamaweCowity searched forfederally listed u" °orp(Dt�edAceas threatened and endangered plant and animal species for Alamance County, NC. There are currently no federally - listed species in Alamance County that are subject to Section 3.o of the Endangered Species Act. 5.2.8 Floodplain Compliance Pine Hill Branch is mapped in a Zone AE Special Flood Hazard Area (SFHA) on Alamance County Flood Insurance e Rate Map Panel 8786. Base flood W Wildlands Engineering, Inc. "'W Page 5.7 Holman Mill Stream Mitigation Site — Part 5 elevations have been defined and a limited detailed study has been performed with non - encroachment areas defined in the Alamance County Flood Insurance Study (FIS). Portions of UTs, UT2, and UT2a do not have designated SFHAs but do lie within the SFHA of Pine Hill Branch. Effective hydraulic modeling for Pine Hill Branch will be obtained from the NC Floodplain Mapping Program. A no -rise condition will be pursued if compatible with Priority 1 restoration and enhancement grading. If a no -rise condition is not attainable, then a Conditional Letter of Map Revision ( CLOMR) will be prepared. Wildlands' engineers have successfully navigated the CLOMR process for several similar full - delivery project sites. A Letter of Map Revision (LOMR) will be completed, if required, after construction using as -built survey data. 5.2.9 Site Constraints and Access The entire easement area can be accessed for construction, monitoring, and long term stewardship from existing site access points located along Clark Road and Holman Mill Road as shown on Figure 2. Most of the reach lengths are accessible via existing farm road or field without having to traverse through forested areas. The proposed mitigation approach does not include any easement crossings. Approximately 2.2 acres in the northeastern corner of the property will be inaccessible to the landowner upon closing the easement. Wildlands has agreed to purchase this area fee simple from the landowner and may include this are in the easement. All streams proposed for mitigation credit provide the required minimum riparian buffer for Piedmont streams. Fencing will be required for this site to exclude cattle access and any other potential sources for damage to the site. The easement area will be marked per NCEEP Guidelines for Full Delivery Requirement for Completion of Survey for Conservation Easements (V13, 8/2013). There are no other known utilities or other constraints on the proposed project site. The Flying Dove Field Airport is 4.8 miles from the project site. This is a privately owned airport in Chatham County with two grass runways on site. There is one single engine airplane based on the field. Wildlands has executed option agreements to purchase conservation easements on the properties. The conservation easement agreements will ensure the right of entry abilities of Wildlands, its contractors, and the future easement holder in any future land transactions. 5.3 Project Development The Wildlands Team proposes to restore a high quality of ecological function to the streams and riparian corridors as well as adjacent floodplain wetlands (no wetland credit requested) on the Holman Mill project site. The project design will ensure that no adverse impacts to existing wetlands or riparian buffers occur. Different management objectives are proposed for different portions of the project area. These activities are discussed below and summarized in Table 5.5. Figure 6 illustrates the conceptual design for the Site. The major goals of project restoration will be to improve water quality in the Pine Hill Branch watershed by filtering nutrients from adjacent cattle pastures and reducing sediment inputs through buffer reestablishment, to achieve improved floodplain and wetland function, and to improve habitat for macro invertebrate communities through reestablishment of natural stream function, bed form structure, and reduction in sedimentation. The Site fully supports the Cataloging Unit (CU) -wide functional objectives stated in the RFP to reduce and control both nutrient and sediment inputs in the Cape Fear 03030002 River Basin. Wildlands Engineering, Inc. Page 5.8 Holman Mill Stream Mitigation Site — Part 5 5.3.1 Streams The current stream conditions at the Site can be characterized as shifting between unstable and moderately stable through the project length. Wildlands staff assessed conditions through the project such as level of incision, bank stability, and width /depth ratio in orderto determine which areas could be stabilized in place and which required full restoration. This assessment provided the basis for a concept plan that includes preservation (with buffer enhancement), Enhancement II, and a restoration approaches. The diverse approach to project design was developed to comply with anticipated regulatory review and provide the maximum ecological uplift. Pine Hill Branch ranges from stable to moderately stable through the project site. A series of small historic mill dams that have deteriorated to piles of cobble and boulders hold stream grade intermittently throughout the project reach. Generally cross sectional area is lower immediately above these remnant structures than below the structures. Although cattle are fenced off from direct access into the creek, the wooded buffer along the left stream bank ranges from o -15 feet through most of the project length allowing for direct nutrient inputs into the system. Due to the moderate to high quality stream conditions, this reach is proposed as preservation however the riparian buffer along the left stream bank will be restored to the edge of the easement. Wildlands is proposing to restore and /or preserve a minimum of 75 -foot buffers with an average of loo -foot buffers along this reach which is greater than the required 50-foot buffer. Due to the level of functional uplift proposed for this preservation reach, a 5:1 mitigation ratio is supported by the EEP Stream Preservation Guidance dated November 7, 2011. UT1 is generally not incised throughout the project length, likely due to bedrock control and minimal shear stress in this small drainage. Streambank instability is largely due to cattle access throughout the entire length of the project (Figure 2). Several sections of the channel are significantly enlarged where cattle wallow in the channel for extended periods. An Enhancement II approach will be used through the majority of the channel where it is expected to recover quickly through natural processes upon fencing cattle out of the creek and restoring a natural buffer. In the sections where the channel x is significantly enlarged, a restoration approach will be used to create a new stable, functional stream system. A competence analysis based on pavement /subpavement a'z P samples collected at the Site shows the channel has excess a shear stress relative to sediment composition indicating a degradational condition. Figure 6 depicts the approximate areas where each of these approaches will be used. Reach 1 of UTz is accessed by cattle but due to the fact that the reach is not incised and has minimal erosion, an Enhancement II approach is proposed. Wildlands will fence out cattle, enhance the riparian buffer, and stabilize isolated Wildlands Engineering, Inc. Page 5.9 Holman Mill Stream Mitigation Site — Part 5 erosion along this section of UTz. Reach 2 of UTz is incised, is heavily utilized by cattle, and has eroded and trampled stream banks. A competence analysis based on pavement/subpavement samples collected at the Site shows the channel has excess shear stress relative to sediment composition indicating a degradational condition. Although Reach 2 of UTz classified as a sand bed system, the distribution is bi -modal meaning that a competence analysis is a valid approach. This section will be restored using a Priority 1 restoration approach but will include a short Priority 2 transition section where UTz ties into Pine Hill Branch. UT2a is incised and unstable along its entire reach. A competence analysis based on pavement /subpavement samples collected at the Site shows the channel has excess shear stress relative to sediment composition indicating a degradational condition. Wildlands will restore this reach using a Priority s restoration approach although a short Priority z section will be required at the upstream end to bring the reach up to reconnect with the historic floodplain. UTzb is incised and impacted by cattle access. This intermittent drainage provides a conveyance for seasonal flows and is an important part of the watershed, delivering upland runoff from the agricultural site to UTz and Pine Hill Branch. Wildlands will use an Enhancement II approach to fence out cattle, restore a riparian buffer, and stabilize isolated erosion along UTzb. All restoration reaches on the project will be designed to create stable, functional stream channels based on reference reach and sediment transport analysis. Dimension, pattern and profile will be designed to allow for frequent overbank flooding, provide stable bank slopes, and enable biological lift. Establishing vertical and lateral stability will provide hydrologic connectivity between creeks and floodplains. Invasive vegetation removal, cattle exclusion, and establishing stable bank slopes will allow for a native and diverse riparian zone to develop and improve nutrient removal. A diverse bedform will provide habitat for different species of insects, fish, and amphibians. This diverse bedform will be established using in- stream structures appropriate for the geomorphic setting such as log weirs, log vanes, and constructed riffles. Existing coarse bed material and bedrock outcroppings on the property will allow for harvesting of native rock on site for riffle construction. Hardwood trees can be harvested from upland areas around the property for log and wood structures. Wildlands will begin the project by identifying the best design approach to meet the stated project objectives and implement the appropriate degree of intervention. A combination of analog, empirical, and analytical design approaches will potentially be used. Reference streams will be identified and will serve as one of the primary sources of information on which designs are based. Modeling and other detailed analyses will be used as appropriate to develop or verify designs. Wildlands has developed a general approach to be used as the basis for stream restoration design and has begun on -going coordination with EEP on the procedures. The approach, which will be tailored to each site, continues to develop as additional projects are implemented. Some of the key elements of the methods are described below. 5.3.2 Channel Hydrology Generally, stream designs will be based on a design discharge range which, in most cases, will be an approximation of the bankfull discharge but will be selected to meet the objectives of the design. The Wildlands Engineering, Inc. Page 5.10 Holman Mill Stream Mitigation Site — Part 5 discharge will be determined through detailed hydrologic analyses using the best available information such as local or regional stream gage records, empirical regional stream flow estimates, hydrologic modeling results, and reference stream flows. Other discharges (such as baseflow or flows to support in- stream habitat features) will also be considered during the design process based on the specific project objectives. The design will be refined or validated with sediment transport analysis. 5.3.3 Sediment Transport Sediment transport is an extremely complicated process and the appropriate level of analysis must be determined for each specific design. This determination is based on watershed assessment, local stream observations, reference conditions, and other sources of information. Generally, these assessments will lead to one of two levels of sediment transport analysis and a corresponding design approach. For streams that are gravel or cobble bed sites and have a low bed load, threshold channels can be designed based on discharge and sediment transport competence analysis. These channels are not expected to be prone to excessive morphologic change and the project objectives will include that channel slope, geometry, and bedforms do not change significantly overtime. Other streams, including those with sand or silt bed material and those that have a moderate to high bedload will require more detailed sediment transport studies and must be designed as alluvial channels. These conditions must be considered when establishing design objectives as alluvial channels are expected to adjust their slope, geometry, and bedforms overtime. In these cases a capacity analysis with data collection and /or detailed modeling is an important component of the design. Detailed analysis involves several tools, including SAMwin, Copeland stability curve, and HEC -RAS sediment transport module. However, alluvial channels will most often be designed with controls at key locations to prevent rapid, significant change. 5.3.4 Nutrient Reduction On -site nutrient reduction will be achieved by removing cattle and establishing riparian buffers along both banks of the streams within the project area. The project area currently consists primarily of pastureland. An estimate of the percent reduction in nitrogen and phosphorus was made using a spreadsheet based on typical nutrient loading in the Piedmont region. Pre - project conditions reflected pastureland within the project area while post - project conditions modeled the project area as wooded. The worksheet estimated that total nitrogen (TN) would be reduced by 34% while total phosphorus (TP) will be reduced by6o %. A copy of the spreadsheet results can be found in Appendix B. 5.3.5 Vegetation Plan The Site will be planted following construction of the restoration project. The planting plan will be based on the reference community located along the right bank of Pine Hill Branch and will be developed to restore appropriate strata (canopy, understory, shrub, and herbaceous layers). The canopy will be restored through planting of bare root trees. The understory and shrub layers will be restored through a combination of planting bare root, low growth species and installing live stake shrub species. The herbaceous layer will be restored by seeding the disturbed area with a native seed mix with an emphasis placed on creating good soil contact to encourage germination. 5.4 Proposed Mitigation The Site will be a combination of stream restoration, enhancement, and preservation. Wildlands proposes to generate 3,656 SMUs (Table 5.4 and Figure 6). The mitigation credit calculation was derived using the US Army Corps of Engineers' Stream Mitigation Guidance and was based on Wildlands' conceptual design for maximum ecological uplift. Given the existing conditions of the stream channels and wetland zones, the disturbance factors, and the constraints, management Wildlands Engineering, Inc. Page 5.11 Holman Mill Stream Mitigation Site — Part 5 objectives for each reach have been established. The management objective, the mitigation type, and proposed amount of stream mitigation are presented below. Table 5.4 Mitigation Units proposed for the Holman Mill Stream Mitigation Site Stream Mitigation Units Parcel ID Number Memorandum of Option Deed Book and Page Number Type of Length Ratio Mitigation Reach Management Objectives Mitigation (feet) Units (SMUs) UT1 (Enhancement Fence out livestock. Establish Enhancement II 2,151 1:2.5 86o native riparian buffer. Sections) Restore appropriate dimension, UT1 pattern, and profile. Install habitat (Restoration structures, allow bankfull floodplain Restoration 440 1:1 440 Sections) access. Establish native riparian buffer. UT2 (Reach 1) Fence out livestock. Enhance Enhancement II 660 1:2. 5 264 existing native riparian buffer. Restore appropriate dimension, pattern, and profile. Install habitat UT2 (Reach 2) structures, allow bankfull floodplain Restoration 771 1:1 771 access. Establish native riparian b uffe r. Restore appropriate dimension, pattern, and profile. Install habitat UT2a structures, allow bankfull floodplain Restoration 402 1:1 402 access. Establish native riparian buffer. UT2b Fence out livestock. Establish Enhancement II 475 1:2.5 190 native riparian buffer. Fence livestock out of riparian Pine Hill buffer. Preserve and establish Preservation 3,646 1:5 729 Branch native riparian buffer. Total 8,545 3,656 SMUs 5.5 Current Ownership The Site is located on two parcels owned bytwo landowners, M Darryl Lindley Revocable Trust and Hadley Revocable Trust. Landowners, parcel identification numbers, and deed book and page numbers for the Memorandums of Option are summarized in Table 5.5. The Option Agreements for the general project area have been signed by the property owners and Memorandums of Option are recorded at the Alamance County Register of Deeds. The option agreements allow Wildlands to restrict the land use in perpetuity through a conservation easement. Copies of the recorded Memorandums of Option are included in Appendix B. Table 5..5 Property Owners for the Holman Mill Stream Mitigation Site Property Owner Parcel ID Number Memorandum of Option Deed Book and Page Number M Darryl Lindley Revocable Trust 8786552224 3268,46o Hadley Revocable Trust 8786743937 3274,215-218 Wildlands Engineering, Inc. Page 5.12 Holman Mill Stream Mitigation Site — Part 5 5.6 Project Phasing Wildlands has experience handling tightly - scheduled projects with a number of stakeholders. We understand the importance of clear communication and adherence to deadlines. We will establish additional internal deadlines to keep the project milestones on track. Each task will be staffed with the appropriate technical and management staff to ensure quality and timely completion. Table 5.6 provides a summary of the major project milestones. Table 5.6 Project Schedule for the Holman Mill Stream Mitigation Site Wildlands Engineering, Inc. Page 5.13 Holman Mill Stream Mitigation Site— Part 5 Proposed Completion Date Project Milestone Proposed Time to Completion (assuming NTP on 9 (from date of NTP) April 1, 2014) Task i. CE Document 3 months July 1, 2014 Task 2. Submit Recorded Conservation Easement on 1 year, 3 months July 1, 2015 the Site Task 3. Mitigation Plan Approved by 1 year April 1, 2015 EEP Task 4. Mitigation Site Earthwork i year, 11 months March 1, 2016 Completed Task 5. Mitigation Site Planting and Installation of Monitoring 2 years, 3 months April 1, 2016 Devices Task 6. Baseline Monitoring Report (Including As -Built Drawings) 2 years, 8 months July 1, 2016 Approved by EEP Task 7. Submit Monitoring Report #1 to EEP (meets success 2 years, 10 months December 1, 2016 criteria) Task 8. Submit Monitoring Report #2 to EEP (meets success 3 years, 8 months December 1, 2017 criteria) Task 9. Submit Monitoring Report #3 to EEP(meets success 4 years, 8 months December 1, 2018 criteria) Task 10. Submit Monitoring Report #4 to EEP (meets success 5 years, 8 months December 1, 2019 criteria) Task 11. Submit Monitoring Report #5 to EEP (meets success 6 years, 8 months December 1, 2020 criteria) Task 12. Submit Monitoring Report #6 to EEP (meets success 7 years, 8 months December 1, 2021 criteria) Task 13. Submit Monitoring Report #7 to EEP (meets success 8 years, 8 months December 1, 2022 criteria) and complete Close - Out Process Wildlands Engineering, Inc. Page 5.13 Holman Mill Stream Mitigation Site— Part 5 5.7 Success Criteria The stream restoration performance criteria for the project site will follow approved performance criteria presented in the EEP Mitigation Plan Template (version 2.2, 6/o8/2012), the EEP Monitoring Requirements and Performance Standards for Stream and /or Wetland Mitigation (11/07 /2011.), and the Stream Mitigation Guidelines issued in April 2003 bythe USACE and NCDWQ. Annual monitoring and semi - annual site visits will be conducted to assess the condition of the finished project. The stream mitigation sections of the project will be assigned specific performance criteria components for hydrology, vegetation, and morphology. Performance criteria will be evaluated throughout the seven (7) year post- construction monitoring. If all performance criteria have been successfully met and two bankfull events have occurred during separate years, Wildlands may propose to terminate stream and /or vegetation monitoring after Year 5, in accordance with the Early Closure Provision in the EEP Monitoring Requirements and Performance Standards for Stream and /or Wetland Mitigation (November 7, 2011). An outline of the performance criteria components follows. 5.7.3. Stream Morphological Parameters and Channel Stability Dimension Riffle cross - sections on the restoration reaches should be stable and should show little change in bankfull area, maximum depth ratio, and width -to -depth ratio. Per EEP guidance, bank height ratios shall not exceed 1.2 and entrenchment ratios shall be at least 2.2 for restored channels to be considered stable. All riffle cross - sections should fall within the parameters defined for channels of the appropriate Rosgen stream type. If any changes do occur, these changes will be evaluated to assess whether the stream channel is showing signs of instability. Indicators of instability include a vertically incising thalweg or eroding channel banks. Changes in the channel that indicate a movement toward stability or enhanced habitat include a decrease in the width -to- depth ratio in meandering channels or an increase in pool depth. Remedial action would not be taken if channel changes indicate a movement toward stability. In order to monitor the channel dimension, one (1) permanent cross - sections will be installed per 20 bankfull widths along stream restoration reaches, with riffle and pool sections in proportion to EEP guidance. Each cross - section will be permanently marked with pins to establish its location. Cross - section surveys will include points measured at all breaks in slope, including top of bank, bankfull, edge of water, and thalweg. If moderate bank erosion is observed within permanent pool cross - sections during the monitoring period, an array of bank pins will be installed in the permanent cross - section where erosion is occurring for reaches with a bankfull width of greater than three feet. Bank pins will be installed on the outside bend of the cross - section in at least three locations one (1) in upper third of the pool, one (1) at the permanent cross - section, and one (1) in the lower third of the pool). Bank pins will be monitored by measuring exposed rebar and maintaining pins flush to bank to capture bank erosion progression. Annual cross - section and bank pin survey (if applicable) will be conducted in monitoring years one (1), two (2), three (3), five (5), and seven (7). Profile and Pattern Longitudinal profile surveys will not be conducted during the seven (7) year monitoring period unless other indicators during the annual monitoring indicate a trend toward vertical and lateral instability. If Wildlands Engineering, Inc. Page 5.14 Holman Mill Stream Mitigation Site — Part 5 a longitudinal profile is deemed necessary, monitoring will follow standards as described in the EEP Monitoring Requirements and Performance Standards for Stream and/or Wetland Mitigation (11/07/2011) and the 2003 USACE and NCDWQ Stream Mitigation Guidance forthe necessary reaches. Substrate Substrate materials in the restoration reaches should indicate a progression towards orthe maintenance of coarser materials in the riffle features and smaller particles in the pool features. A reach -wide pebble count will be performed in each restoration reach each year for classification purposes. A pebble count will be performed at each surveyed riffle to characterize the pavement. 5.7.2 Hydrology Stream Two (2) bankfull flow events must be documented on the restoration reaches within the seven (7) year monitoring period. The two (2) bankfull events must occur in separate years. Stream monitoring will continue until success criteria in the form of two bankfull events in separate years have been documented. Bankfull events will be documented using photographs and either a crest gage or a pressure transducer, as appropriate for site conditions. The selected measurement device will be installed in the stream within a surveyed riffle cross - section. The device will be checked at each site visit to determine if a bankfull event has occurred. Photographs will also be used to document the occurrence of debris lines and sediment deposition. 5.7.3 Vegetation The final vegetative success criteria will be the survival of 210 planted stems per acre in the riparian corridor at the end of the required monitoring period (year seven (7). The interim measure of vegetative success for the site will be the survival of at least 320 planted stems per acre at the end of the third (3) monitoring year and at least 26o stems per acre at the end of the fifth (5) year of monitoring. Planted vegetation must average 10 feet in height in each plot at the end of the seventh (7) year of monitoring. If this performance standard is met by year five (5) and stem density is trending towards success (i.e., no less than 26o five year old stems /acre), monitoring of vegetation on the site may be terminated with written approval by the USACE in consultation with the NC Interagency Review Team. The extent of invasive species coverage will also be monitored and controlled as necessary throughout the required monitoring period (year five or seven). Vegetation monitoring quadrants will be installed across the restoration site to measure the survival of the planted trees. The number of monitoring quadrants required will based on the EEP monitoring guidance documents (version 1.5, 6/08/12). Vegetation monitoring will occur in the fall and will follow the CVS -EEP Protocol for Recording Vegetation (2006). 5.7.4 Other Parameters Photo Reference Stations Photographs will be taken once a year to visually document stability for seven (7) years following construction. Permanent markers will be established and located with GPS equipment so that the same qVW Wildlands Engineering, Inc. Page 5.15 Holman Mill Stream Mitigation Site — Part 5 locations and view directions on the site are photographed each year. Photos will be used to monitor restoration and enhancement stream reaches as well as vegetation plots and wetland areas. Longitudinal reference photos will be established at the tail of riffles approximately every zoo LF along the channel by taking a photo looking upstream and downstream. Cross - sectional photos will be taken of each permanent cross - section looking upstream and downstream. Reference photos will also be taken for each of the vegetation plots and within wetland areas. Representative digital photos of each permanent photo point, cross - section and vegetation plot will be taken on the same day that the stream and vegetation assessments are conducted. The photographer will make every effort to consistently maintain the same area in each photo overtime. Photographs should illustrate the site's vegetation and morphological stability on an annual basis. Cross - section photos should demonstrate no excessive erosion or degradation of the banks. Longitudinal photos should indicate the absence of persistent bars within the channel or vertical incision. Grade control structures should remain stable. Deposition of sediment on the bank side of vane arms is preferable. Maintenance of scour pools on the channel side of vane arms is expected. Visual Assessments Visual assessments will be performed along all stream and wetland areas on a semi - annual basis during the seven (7) year monitoring period. Problem areas will be noted such as channel instability (i.e. lateral and /or vertical instability, instream structure failure /instability and /or piping, headcuts), vegetation health (e.g. low stem density, vegetation mortality, invasive species or encroachment), beaver activity, or livestock access. Areas of concern will be mapped and photographed accompanied by a written description in the annual report. Problem areas with be re- evaluated during each subsequent visual assessment. Should remedial actions be required, recommendations will be provided in the annual monitoring report. eenthic Macroinvertebrates If required by NCDWQ as part of the projects permitting process, benthic macro invertebrate sampling will be performed on the restored site. Any required sampling will be performed using NCDWQ Standard Operating Procedures for Benthic Macro invertebrates, July 2006. 5.7.5 Reporting Performance Criteria Using the EEP Baseline Monitoring Plan Template (version 2.0, 10/14/10), a baseline monitoring document and as -built record drawings of the project will be developed within 6o days of the planting completion and monitoring installation on the restored site. Monitoring reports will be prepared in the fall of each year of monitoring and submitted to EEP. These reports will be based on the EEP Monitoring Report Template (version 1.5, 6/08/12). The monitoring period will extend seven years beyond completion of construction or until performance criteria have been met per the criteria stated in the EEP Monitoring Requirements and Performance Standards for Stream and /or Wetland Mitigation (3-1/7/2012.). 5.7.6 Maintenance and Contingency Plans The Wildlands Team will develop necessary adaptive measures or implement appropriate remedial actions in the event that the site or a specific component of the site fails to achieve the success criteria outlined above. The project — specific monitoring plan developed during the design phase will identify an appropriate threshold for maintenance intervention based on the monitored items. Any actions implemented will be designed to achieve the success criteria specified previously, and will include a work schedule and updated monitoring criteria. Wildlands Engineering, Inc. Page 5.16 Holman Mill Stream Mitigation Site — Part 5 Figure 2 Site Map W I L D L A N D S 0 400 Feet Holman Mill Stream Mitigation Site ENGINEERING I I I Cape Fear River Basin 03030002 Alamance County, NC MINIM- �INIr Project Location Proposed Conservation Easement 95t ? I \ ,(G`�' //1 \.i� O - `�� `NFS crl -` J \J�,Ji � ..� . ` : �' `�t�_• r- :`�i� ping • ` /..� , \ / / yl � ��it � O�•� r `� x.37/ � Ir --�\ //ll \ - ,. -�i J � ` i •..��; �.. \ Cam% u. xd+ `4 I cIA♦ r_, Tower e a _ `iv �"S .2352} C/ 1, 1 ALAM C— CQ / �t23,i � \` !•�/ r V/iii Jl- �" / ✓'. r /'� �'� \ \1�iA� 342 _ i ' r, vl/ Q�� -1\ `t , •1\ ��.5 � 1132`1 � �U Q♦� i . r ��_�� -I, �il b�0�'� �t \�l` if _- ',, .•` •� ,�./" �l ... �1 ,.11 16 / ,. ��+ l�\ • x687, r � � ,• . � �(, ( ,/ ` 111'1- � / ��/ r�. 1. � Crutchfiel ,Crossro cts, USG:Ai.5 minute • /ographic W I L D L A N D S 0 2,000 Feet ENGINEERING I I I 79.3860% Figure 3 Topographic Map Holman Mill Stream Mitigation Site Cape Fear River Basin 03030002 Alamance County, NC �a �u /C\ pFv 1I i 1 JAI i.:li +rr/e ra is r, I �m�1 r4)j))I��! 1 `@W,1110 .t I'fr' /1 % /N��`J yy� ' i �r y t r 2011 Aerial Photography pFv 1I i 1 JAI i.:li +rr/e ra is r, I �m�1 r4)j))I��! 1 `@W,1110 .t I'fr' /1 % /N��`J yy� ' i �r y t r Figure 5 Soils Map W I L D L A N D S 0 400 Feet Holman Mill Stream Mitigation Site ENGINEERING I I Cape Fear River Basin 03030002 Alamance County, NC Figure 6 Concept Map W I L D L A N D S 0 400 Feet Holman Mill Stream Mitigation Site ENGINEERING I I I Cape Fear River Basin 03030002 Alamance County, NC h On s't ...a Vi J fy I a..'� } AA f a a� �a ft k1 1iti ,N `s s Z J W-7 OF :i0 3 INQUIRY M 3754328.1 YEAR: 1973 = 500' 4N fi �s �i �s I "! att i L f , -�t{ •_�f � aa};� -.'.fit 4 t q� t 4,k.: t..< J fy I a..'� } AA f a a� �a ft k1 1iti ,N `s s Z J W-7 OF :i0 3 INQUIRY M 3754328.1 YEAR: 1973 = 500' 4N fi �s �i �s