Wetland Recovery Implementation and Assessment Report Johnson Property (126B A 005) 457 Signal Mountain Road Chattanooga, TN 37405

Transcription

1 Wetland Recovery Implementation and Assessment Report Johnson Property (126B A 005) 457 Signal Mountain Road Chattanooga, TN Prepared for: Mike Reed Thomas Brothers Construction 7849 Dayton Blvd Hixson, TN Prepared by: Wilson And Associates, P.C. Engineering Surveying 108 Beasley Dr. Franklin, TN Ph:(615) Fax:(615) May 23, 2005

2 Wilson And Associates, P.C. Engineering Surveying 108 Beasley Dr. Franklin, TN Ph:(615) Fax:(615) May 23, 2005 Mike Reed Thomas Brothers Construction 7849 Dayton Blvd Hixson, TN Subject: Wetland Recovery Report Mr. Reed: Qualified personnel from Wilson & Associates have inspected recovery actions for the removal of excess fill materials from a floodplain wetland site located on 457 Signal Mountain Road. As previously defined in a letter dated April 1, 2005, Wilson and Associates personnel have prepared a report assessing the effective completion of recovery actions. The accompanying implementation and assessment report consists of the documentation of fill removal, field determination results for wetland site characteristics, and erosion/sediment control recommendations. We hereby submit the following report for your review and records. If you have any questions or comments please contact Taylor McDonald at or myself at Sincerely, Andy Carroll Environmental Geologist Enc: Report

3 Table of Contents Page 1.0 Site Location Project Background Methods Wetland Characterization Soil Investigations Hydrologic Investigations Vegetation Analysis Observations and Results Soil Investigations Hydrologic Investigations Vegetation Analysis Conclusions and Recommendations. 4 Appendices Appendix A Figures Appendix B Images

4 1.0 Site Location The project site is located at 457 Signal Mountain Road, approximately 220ft west of street centerline. The wetland site (the site ) consists of area of less than 2 acres located on Hamilton County property parcel 126B A 005. The property parcel is bound to the west by a rail line, to the south by the Baylor School, to the east by Signal Mountain Road, and to the North by a small commercial shopping center. The site is located in the transition zone between upland terrain and Stingers branch, which flows through the southernmost section of the property to its confluence with Baylor Lake and the Tennessee River. The site is located within the 100 and 500 year floodplains at an average elevation of 645 ft above sea level. A site location map (Figure 1) and a site vicinity map (Figure 2) are included in Appendix A of this report. 2.0 Project Background While performing material filling activities on the above mentioned property parcel, wetland areas were partially covered. The US Fish and Wildlife Service (USFWS) has classified the area as [P] Palustrine, [FO] Forested, [1] Broad-Leaved Deciduous, [C] Seasonally Flooded wetland (PFO1C). Wilson and Associates personnel developed a wetland recovery plan for the removal of excess fill from the floodplain wetland. The plan recommended that fill materials be removed to a reference elevation and the original fill footprint (Image 1 & 2). This plan also stated that following the removal of fill, Wilson and Associates would: Classify hydric soils for three reference sites using a Munsell Soil Color Chart Compare cored site soils with reference soils to verify that native hydric soils are restored to ground surface Provide recommendations for the reestablishment of wetland vegetation Provide a plan for temporary erosion prevention and sediment control. 3.1 Wetland Characterization 3.0 Methods Wetlands are defined as transitional lands located between terrestrial and aquatic systems that exhibit the following characteristics: 1) the presence of hydric soil (moist/saturated soils) 2) the presence of hydrologic conditions (terrain/water table) 3) the ability to support hydrophytic vegetation (strong affinity for water). Using these three indices it is possible to differentiate upland (terrestrial) areas, transitional areas (bottomlands, marshes, bogs, swamps, and wet meadows), and deep water, aquatic zones (streams, lakes, ponds, and rivers). 1

5 3.2 Soil Investigations As described in the Wetland Recovery Plan, Wilson and Associates personnel assessed post-removal surface soil conditions on site. This assessment involved the comparison of reference site soils and excavation area site soils. First, fill materials were sampled and classified. Next, three reference soil samples were collected in the undisturbed wetland area located on property, south of the fill materials (Figure 3). Samples were taken using a 3 inch diameter, split-spoon, hand auger with a 4 foot shaft (Image 3 & 4). Cored soils were removed from the auger sampler, described, and classified with a Munsell Soil Color Chart. Following reference site sampling, 2 transects consisting of sampling locations spaced at 30 foot intervals were laid out between the toe of the fill slope and the boundary of the undisturbed area (Image 5). The easternmost transect was spaced 6 feet west of the toe of the fill slope and the westernmost transect was placed 10 feet east of the undisturbed area (Figure 3). Soil samples were collected at each location with a hand auger, described, and classified with a Munsell Soil Color Chart. 3.3 Hydrologic Investigations Since an existing wetland classification existed on site, hydrologic conditions were deemed conducive for hydric soils and hydrophytic vegetation. Wilson and Associates personnel documented the elevation of existing, undisturbed wetlands, and requested that fill material be removed to this elevation surface. Field observations and documentation were used to verify that pre-fill site hydrology was restored. 3.4 Vegetation Analysis Minimal vegetation analysis efforts were needed since the wetland was designated with a USFWS classification. The USFWS provides a list of vegetation for the wetland classification of PFO1C. This list and information provided by the Field Guide to Nontidal Wetland Identification were used to document existing wetland species in undisturbed areas and provide suggested planting lists for revegetation efforts. Trees, shrubs, and grasses were identified in the field and documented with a digital camera. These photographs are included in Appendix B of this report. 4.1 Soil Investigations 4.0 Observations and Results A fill material sample collected at the toe of the slope consisted of brownish yellow, very fine fine clay matrix bearing fine coarse cherty rubble, limestone gravel, asphalt, coal fragments, and organic debris. The fill material was classified with a Munsell Soil Color classification of 10YR 6/6. 2

6 Reference site core samples consisted of moist, dark grayish brown very dark grayish brown, very fine fine grained silts and clays, bearing 20-40% orange brown mottles, and approximately 10-20% fine organic debris. The Munsell Soil color classifications for these samples were 10YR 3.5/2. Core samples taken from the recently excavated areas, located along transects 1 and 2 consisted of dark grayish brown grayish brown, very fine fine clays and silts bearing 10-30% orange brown mottles, and < 10% organic debris. The following table summarizes soil types and occurrences (Table 1). Sample Type Sample ID Code(s) Munsell Class Fill Material FM-1 10YR 6/6 Reference Sample RS-1,2,3 10YR 3.5/2 Excavated Area EA-1,19 10YR 4.5/2 Excavated Area EA-2,3,6,7,13,14,15,16,17,18 10YR 4/2 Excavated Area EA-4,5,8,9,10,11,12 10YR 3.5/2 Table 1. Soil sample locations, identification codes, and classifications. 4.2 Hydrologic Investigation Standing water was documented in newly excavated areas as well as at undisturbed wetland areas (Image 6). Surface groundwater elevations (top of the water table) were observed 4-6 inches beneath ground surface in sampling core holes located above surface water locations. 4.3 Vegetation Analysis A variety of hydrophytic trees, shrubs, and grasses were documented during field activities. A table of vegetation observed has been included (Table 2). Red Maple Black Walnut Water Oak Sweet Gum Tulip Poplar Sycamore Jumpseed Wingstem Common Greenbrier Cinnamon Fern False lily-of-the-valley Acer rubrum Junglans nigra Quercas nigra Liquidambar styraciflua Liriodendron tulipfera Plantanus occidentalis Polygonum sagittatum Verbinesina alternifolia Smilax rotundifolia Osmunda cinnamomea Maianthemum dilatatum Table 2. Plants observed in the undisturbed wetland. These plants are facultative wetland species. They are not obligate wetland species. Facultative wetland species comprised approximately 80-90% of vegetation encountered. 3

7 These species are indicative of a temporarily or seasonally flooded wetland. Images depicting vegetation encountered are included in Appendix B to this report. 5.0 Conclusions and Recommendations Wilson and Associates personnel observed and documented post fill removal conditions at the identified site. Soil comparisons between fill materials, reference samples, and excavated area samples indicate that fill material has been successfully removed. Soils located at the southernmost section of the site most closely resemble reference wetland soils. Only the two northernmost and highest elevated sample locations possessed characteristics similar to fill materials. Hydrologic conditions such as standing surface water and the presence of a shallow water table were observed on site and depicted restored hydrologic function. Based upon these observations, it appears that hydric soils and hydrologic conditions are successfully restored on site. To fully restore the wetland, Wilson and Associates personnel recommend that vegetation listed in Table 2 of this report be planted in the excavated area. These plants best fit the seasonal flooding conditions and natural distributions present on the property. Erosion prevention and sediment control measures should be taken to prevent the impairment of the restored wetland area. A silt fence should be placed along the contour of the toe of the fill slope to provide a barrier for sediment deposition in the restored wetland. Fill material slopes should be stabilized with seed, mulch, and/or sod to prevent erosion. 4

8 Appendix A Figure 1. Site location map. Figure 2. Site vicinity map. Area within blue rectangle represents area of interest.

9 Figure 3. Map depicting reference site samples (green), transects (red), and existing fill materials (orange). Image depicted was acquired in 2002 and does not completely portray the current extent of fill.

10 Appendix B Image 1. View of fill material slope and recently excavated area facing south. Note the darker moist surface soils and standing water located in the center of the image. Image 2. View of the eastern most extent of the excavated area, as seen from the top of fill slope bank, facing southeast.

11 Image 3. View of soil sampling at reference site #3 with hand auger. Image taken facing east. Image 4. View of soil sampling at reference site #2 with hand auger. Image taken facing south.

12 Image 5. View of sampling locations along toe of slope. Orange flags denote location along transect. Image taken facing southeast. Image 6. View of surface water in area where excess fill materials were removed. Image taken facing southwest from top of fill bank.

13 Image 7. View of water oak, box elder, asters, ferns and miscellaneous grasses typical of forested wetlands. Image captured facing west. Image 8. View of false lilies of the valley, common greenbrier, red maples, sycamores, and tulip poplars. Image captured facing south.