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SDP200500002 Certified Engineer's Report 2005-01-25
w. Rivanna Water and Sewer Authority Moore's Creek Wastewater Treatment Plant Influent Screen Building Site Development Plan Submittal Project Book Including Forms, Letters, Erosion Control Narrative, Stormdrainage Calculations, Subsurface Study and Related Specifications NIN Submitted to: Albemarle County December 2004 ism Saw Hazen and Sawyer Environmental Engineers & Scientists • r.■ las Soils MIN The project site is located in an upland area of the Piedmont Plateau, at the western edge of the Piedmont Physiographic Province, an area underlain by ancient metamorphic rocks. This area is underlain by the Catoctin Formation , of the Precambrian or Cambrian Age. The virgin soils encountered in this area are the residual product of in -place chemical and mechanical weathering of the parent bedrock formation that underlies the site. These materials consist of clayey soils .. near the surface where soil weathering is more advanced, underlain by sandy SILTS and silty SANDS. The boundary between soil and rock is often times not sharply defined. The NMI transitional term "Hard or Soft Weathered Rock" is normally used for the material found overlying the parent bedrock. Surficial soils typically contain root mat and /or other fibrous organic matter and are generally unsuitable for engineering purposes. Surficial soils were encountered at each of the boring locations to a depth of 4 inches. Actual depths will vary in unexplored areas of the site. Existing fill soils were encountered at several boring locations. Existing fill soils may include any materials deposited by man. Residual soils were encountered at each of the boring locations below the surficial materials in boring B -2 and below the existing fill soils in borings B -1 and B -3. The sampled residual soils consist of silt, elastic silt, and silty sand. The residual soils were generally tan, brown, reddish brown, and reddish tan in color, with moisture contents visually characterized as moist to very moist. A copy of the subsurface investigation, performed by Froehling & Robertson, Inc, is included in Appendix III of this report. IMIN Critical Areas The majority of the disturbed area will have a low to moderate erosion hazard. The majority of the disturbed area is in tnild to moderately sloping areas where runoff can be filtered with measures such as silt fence and yard /curb inlet erosion control. The critical area during construction will be the slope located immediately to the north of the proposed Screening Building. Control measures including silt fence, temporary and /or permanent seeding, slope protection matting, and inlet erosion control have been provided to limit erosion and sediment transport during construction. After completion of the project, the disturbed area will be stabilized by permanent vegetation as specified in the Specification Section 02910 — Final Grading and Landscaping, attached. The proposed vegetation will prevent long -term erosion after project completion. Erosion and Sediment Control Measures All erosion and sediment control devices and measures have been designed and placed in accordance with the Virginia Erosion and Sediment Control Handbook, Third Edition, 1992. Temporary measures will be used to limit erosion and contain sediment from cleared areas prior to the establishment of vegetation. Once construction, including any structural measures, is complete, and permanent vegetative cover has been established, these measures may be removed with approval from the engineer. Vegetative cover for disturbed areas will consist of grasses as WIN recommended by the Virginia Erosion and Sediment Control Handbook. See the Plans and Specification Section 02910 — Final Grading and Landscaping for the proposed Seeding schedule, attached. The temporary measures proposed for this site include silt fence, slope protection matting, inlet r erosion control and temporary seeding measures as required. The above devices will filter sediment from run -off to prevent sediment from being deposited off -site, while the temporary seeding will limit erosion during construction activities. Permanent measures proposed include peuiianent vegetative plantings. See Specification Section 02276 — Erosion and Sedimentation Control and Section 02910 — Final Grading and Landscaping for further details on these temporary and permanent measures. tea Permanent Stabilization Upon completion of the project, permanent vegetative plantings will be used to achieve stabilization of the site. All temporary erosion and sediment control measures will be removed once the site has been stabilized. All permanent vegetative plantings conform to those specified ire in the Virginia Erosion and Sediment Control Handbook, Third Edition, 1992. See Specification Section 02910 — Final Grading and Landscaping, attached, for the proposed seeding schedule. Ira Storm water Runoff Considerations .r This construction site will have an increase in impervious surface in the post - developed condition. The proposed structures and sidewalk contribute an impervious surface net increase of 2012 square feet. Even though there is an increase in impervious area, the runoff does not increase significantly for the localized drainage area. Runoff calculations indicate a 4.5% increase in stormwater runoff from the area impacted by this construction. See Appendix I for stormwater runoff calculations and a narrative explanation of how they were performed. There are no downstream properties that could be adversely impacted by the proposed development because the property drains directly to Moore's Creek and then to The Rivanna River. Construction Sequence IMO 1) No demolition, construction or land disturbance activities may begin until all erosion control measures have been installed in locations as shown on the perimetr Drawings. If clearing is required for installation of a particular measure, all other Contract as es shown shall be installed first. The clearing of the land necessary for installation of t es particular measure may then proceed. of the 2) Once all measures have been installed, the site shall be cleared and within the limits of disturbance as shown on the Contract Drawings. Efforts sh as all be m necessary made minimize the amount of cleared area exposed at any given time. h tto 3) Once clearing and grubbing is complete, any necessary topsoil stripping may begin. shall be stockpiled on site in the stockpiling areas shown on the Contract Drawings. ract a winos. Stockpile shall receive such temporary seeding measures as may be required. Any soil taken soi offsite shall be stockpiled at locations with all required permits. If offsite location d no have all required permits, the contractor is responsible for obtaining any required p e does not rmits. 4) Demolition, earthwork and construction operations may begin once topsoil has been and stockpiled. removed 5) All pipes shall be installed in accordance with standard construction techniques. "` length of trench in which pipe can be installed in one days time shall be open Only the with spoil material placed on the uphill side of the trench. Piping shall be a at any time, days work to prevent sediment from entering. Trench shall be backfilled at at end d of f ed h days work and disturbed area seeded and mulched within seven (7) days ofbackfill each 6) Temporary soil days to denuded areas stabilization shall be applied within seven (7) d that may not be at final grade but will remain dormant for longer than fourteen (14) days, except that portion of the site on which work will be continuous beyond fourteen (14) days. for 7) Once construction activities are complete, final grading may begin. .r. w 8) Upon completion of final grading, permanent seeding, mulching and fertilizing measures shall be employed on all disturbed areas as per Section 02910 — Final Grading and Landscaping. Permanent soil stabilization shall be applied within seven (7) days after final grade is reached on any portion of the site. All erosion control measures shall remain in place until entire site has been stabilized. 9) Once permanent stabilization has occurred, temporary sediment control measures shall be removed. Any areas disturbed by the removal of these measures shall be returned as closely as possible to original condition and seeded, mulched and fertilized as per Specification Section 02910. Maintenance and Sediment Disposal All sediment and erosion control measures shall be inspected upon installation, at least once every fourteen (14) days and within 48 hours following any runoff producing rainfall event. VIM Repairs to, or replacement of, measures shall occur immediately if necessary and accumulated sediment removed as needed. Sediment shall be removed from the temporary sediment traps when the design volume is reduced by 25 %. Sediment shall be removed from all other erosion control measures when the sediment storage volume of the measure has become 50% full. All removed sediment shall be disposed of in an approved manner at the stockpile location or a location to be designated by the Engineer or Owner. Steps shall be taken at the disposal site to insure that further sediment transport does not occur. All disturbed areas shall be permanently seeded as soon as possible, but in no case later than r.. seven (7) calendar days after construction activities are complete. Areas shall be seeded, fertilized and mulched in accordance with the Seeding schedule in Section 02910 — Final wir Grading and Landscaping, of the Specifications. Appendices Appendix I - Storm Drainage Calculations Appendix II - Specifications web Section 02276 — Erosion and Sedimentation Control Section 02910 — Final Grading and Landscaping Appendix III -- Sub - surface Investigation Appendix IV Contract Drawings 1N. rr rr «r. w r rr. Appendix I — Storm Drainage Calculations Appendix II Specifications ir. Appendix III Sub - surface Investigation Appendix IV Contract Drawings (Provided as Separate Attachment) IMO Moores Creek Wastewater Treatment Plant ... Influent Screen Building Stormwater Calculation Narrative A. Overview The Moores Creek Wastewater Treatment Plant (WWTP) is located off of Moores Creek Lane. The project will consist of construction of an influent screen building and all associated equipment and piping. The contractor will demolish steps, sidewalk, paving, curb and gutter, various piping and mechanical equipment within the footprint of the IMO proposed construction. Approximately 0.46 acres will be disturbed for this project. The existing stoiniwater collection system will be used to collect runoff from the proposed construction. The existing system discharges into Moores Creek. B. Pre - Developed and Post - Developed Flow Calculation Calculating pre - developed and post - developed runoff quantities requires gathering several pieces of information concerning the drainage areas prior to the calculating the l .. flows. This necessary information includes: 1. Determining the drainage area to each catch basin. 2. Determining the time of concentration for each area. w.► 3. Calculating the upstream pipe time for each basin, if applicable. 4. Using the combined time of concentration, determine the rainfall intensity for Via each catch basin for the 10 -year storm event using rainfall data from National Weather Service maps from HYDRO -35 and TP -40. 5. Calculating the combined runoff coefficient for each area. The drainage areas were delineated on a topographic map of the site. ism The time of concentration for each drainage area was assumed to be 5 minutes (the minimum allowed by Intensity - Duration- Frequency charts). The flow time in the upstream piping system was computed along the longest path, if applicable. Using the combined time of concentration, the rainfall intensity was determined using Intensity - • Duration - Frequency data for the 10 -year storm event (Intensity- Duration - Frequency table attached at end of narrative). INN The weighted runoff coefficient for each area was determined using values given in EOUSD. The weighted runoff coefficient is determined by using weighted averages after determining the total surface areas of all types of land covers present within the delineated drainage area. Once the above information is determined, the flow may be calculated using the Rational Method. C. Stormwater Calculations The existing stormwater collection system for this wastewater treatment plant site was modeled using concepts and data presented in H.R. Malcom's Elements of Urban Stormwater Design (EOUSD) and the Virginia Erosion and Sediment Control Handbook. Microsoft Excel software was used in the piping calculations. The Rational Method was used to calculate flows for the 10 -year storm event. The Rational Method is as follows: Q =CxIxA .r where: Q = Runoff, cfs C = Rational runoff coefficient, dimensionless I = Rainfall intensity, in. /hr. A = Drainage Area, acres Run -off coefficients, C, for various ground cover conditions are referenced to Exhibit 1 "` in the EOUSD. Rainfall intensities, I, used in the Rational Method were taken from Figure 8.03d and are based on the Time of Concentration, Tc, found using the Kirpich Equation, below. In r most cases, time of concentration is assumed to be five minutes, which is conservative. (L H) 0 385 - Tc 128 where: Tc = Time of Concentration, min. L = Hydraulic Length of Watershed, ft. H = Hydraulic Gradient of Watershed, ft. Flow behavior in the existing piping system was modeled using Manning's Equation, as noted in EOUSD, to calculate velocity and adequacy of pipes. Manning's Equations is as follows: 79 xAxR xS'- 1.49 where: Q = Flow, cfs n = Manning's coefficient, dimensionless A = Cross - sectional area of flow, ft.2 R = Hydraulic radius, ft. S = Longitudinal channel slope, ft. /ft. The collection system was analyzed for existing site conditions and post - construction site sait conditions to determine the increase in flow for the 10 -year storm event and to determine if the existing system would adequately convey the flow generated by the 10 -year storm event without overtopping the catch basins. The stormwater conveyance system was ..r modeled to existing manhole (MH) A -2. No stormwater flows will be generated from proposed improvements to the plant beyond this point. IMP Using flow rates and information on the elevations of the existing catch basins and piping .,. system, the flows were routed through the piping system using methods outlined in EOUSD. Based on these calculation, the existing piping system will contain the post- ,,,., construction flow rates generated by the 10 -year storm event without surcharging the pipe system or overtopping the basins (see pre- construction and post- construction piping system calculation in at end of narrative). ww D. Conclusions The total amount of impervious surface associated with the construction of this project will be 6,200 square feet. This includes all the proposed roadways, structures, and sidewalks. This project will also be removing 4,200 square feet of impervious surface, yielding a net increase of 2,000 square feet (0.05 acres) of additional impervious surface. Nmi When added to the 0.91 acres of existing impervious surface, the total impervious area going to MH A -2 will be 0.96 acres. With a total drainage area going to MH A -2 of 3.0 acres, the additional impervious surface brings the post- developed impervious surface to Joe 32% of the total drained area, up slightly from 30.3% in the pre - developed condition. The post - developed runoff coefficient will therefore be slightly higher than in the pre- ,,.. developed condition due to the increase in impervious surface and the decrease in grassed land cover. The pre - developed flow at the point of interest is 11.8 cfs and the post- .. developed flow is 12.3 cfs. This is an increase of 0.5 cfs or approximately 4.5% at MH A -2 VIPS w. im DEPTH - DURATION - FREQUENCY TABLE LOCATION: Charlottesville RETURN PERIOD r DURATION 2 -YR 5 -YR 10 -YR 25 -YR 50 -YR 100 -YR [in] [in] [in] [in] [in] [in] we 5 min 0.46 0.54 0.59 0.68 0.74 0.81 10 min 0.70 0.85 0.96 1.11 1.23 1.35 15 min 0.87 1.07 1.21 1.41 1.57 1.73 too 30 min 1.06 1.35 1.55 1.83 2.06 2.28 60 min 1.25 1.63 1.90 2.27 2.56 2.85 2 hr 1.55 2.03 2.35 2.81 3.17 3.53 3 hr 1.86 2.42 2.81 3.36 3.78 4.20 "` 6 hr 2.63 3.42 3.96 4.73 5.33 5.93 12 hr 3.31 4.31 4.99 5.96 6.71 7.46 24 hr 4.00 5.20 6.03 _ 7.19 8.10 9.00 r INTENSITY - DURATION- FREQUENCY TABLE O LOCATION: Charlottesville um RETURN PERIOD DURATION 2 -YR 5 -YR 10 -YR 25 -YR 50 -YR 100 -YR ..r [in /hr] [in /hr] [in /hr] [in /hr] [in /hr] [in /hr] 5 min 5.52 6.42 7.10 8.12 8.92 9.72 10 min 4.21 5.09 5.73 6.66 7.39 8.12 w 15 min 3.48 4.27 4.83 5.65 6.29 6.92 30 min 2.11 2.69 • 3.09 3.67 4.11 4.56 60 min 1.25 1.63 1.90 2.27 2.56 2.85 2 hr 0.78 1.01 1.18 1.41 1.59 1.76 i• 3 hr 0.62 0.81 0.94 1.12 1.26 1.40 6 hr 0.44 0.57 0.66 0.79 0.89 0.99 12 hr 0.28 0.36 0.42 0.50 0.56 0.62 ire 24 hr 0.17 0.22 0.25 0.30 0.34 0.38 INPUT DATA: ono LOCATION: Charlottesville DURATION 2 -YR P 100 -YR P SOURCE tee [in] [in] 5 min 0.46 0.81 NOAA HYDRO -35 15 min 0.87 1.73 NOAA HYDRO -35 r 60 min 1.25 2.85 NOAA HYDRO -35 24 hr 4.00 9.00 USWB TP -40 liwa im roc a) N O 0 O CO O O 0 CO O 0 O N CO . 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CO O (0 (D M CO O L O M D) M N D) co co co N- O co 7 C O co O co O O '- O co _ O 66 O O 66 O O O O 66 O Ne v) O O O O O O O O O O O O O L lT O N N N CV O O O N (O CO C In O CO N 7 CO N co O (0 IMO J O O M O O CO 0 O O CO O O 3 t0 O r• r` 10 N ,- O N N N O O O > (O N O) M 6 O O O N N O N (P J C CO CO CO 0 C M CO Cr) CO CO CO O CO co CO ifll O o O CD t O O O O 0 0 0 0 Z11 N- M (7) (O � M N (0 (0 ,- O co a> CO CO 0) O) O O O O N N O O) D co M M M M M M M M M C 0 0 0 7 7 1 Cif 0 0 0 0 O 0 O 0 0 O 0 0 0 O. > 1)) LO if) O 0 LO O 0 (0 (f) N (0 O O O O .- 7 cc; 7 7 r- CO (0 O (O 7 r.: 1- L J r- r Co co (O O (O (f) 0 0 CO (0 (0 M M M M CO M M 0) M M M M CO 3 0) N 7 0 ,- 0 r 0 7 M (O M co • CP O a N N O) r` O CO M r` r- 1)) N (D > � d LL • 7 O (f) ,— N O O .-- O N 6 i+ L £ m ' '- C1) u @ H U OM Q y ! ' D o (0 7 CO t0 ( O O 0 N CO CD C7) LU G M (n CO 0 O LO '7 CO (0 7 7 t0 u) m O U t 0 o O o 0 0 o O O O o 0 0 E CO 3 w N 0 o� 0 L U MO N V) ' N In O c0 (0 (f) CO O O O N O O (0 C O. (� C M 0) 0) 0) 0) 7 7 0 1)) 7 0 r- 0 0 7 0 o 0 0 o O o 0 o o O o 0 0 Y co (U , T �' U C a c d O Ira m • U e- CL v 0 > M O U) to O 0 0 O Q 0 0 0 O 0 N. 0 O m O O 0 c — ° 2 CL c or 15 u O C 0 7 O CO 0 .- 0 N CO 0 ,- (n M E o (ri (ri (ri 1) (ri (fi (ri u i (r; (0 (ri (ri ui •- U rr N 0.) O 7 O 0 0-- O N O O «7 CO O n. F o 0 0 0 0 0 0 0 0 0 0 0 0 sr .... E 0 0 0 0 0 0 0 0 0 0 0 0 0 C H (0 (Ci (fi cfi Ui (fi (fi (ri 6 (fi (ri 10 6 — Q CO N "- 7 7 L0 N r` O O (0 M 0 NNW ~O COI r` r .- CO '- CD 0 7 "- CO 0) 0 L .., L O r O .- O O O N 6 O 0 0 M Q ' ,,,co N C7) 7 C3) (0 r` O co co O r` O o U co O 7 O 7 O (N 0 ills C Q Q O O O O O O O O O O O O O 7 co r-- CO N o Q . - OS Q N N Q Q Q Q m m (n m m Q Q `r U 1 M —) m - 7 '7 T U M 1 U M 7 0 •- 0 r co (P r` gm Q Q Q Q Q Q Q Q Q N Q Q as— m LL U U 0 2 U U 0 U U U 2 Or ..r Appendix II Specifications SECTION 02276 tram EROSION AND SEDIMENTATION CONTROL PART 1 -- GENERAL 1.01 THE REQUIREMENTS A. The Contractor shall employ a Responsible Land Disturber certified in the Commonwealth of Virginia who is responsible for implementing Best Management Practices (BMP's) to prevent rr and minimize erosion and resultant sedimentation in all cleared and grubbed areas during and after construction. This item covers the work necessary for the installation of structure and measures for the prevention and control of soil erosion. The Contractor shall furnish all ,.. material, labor and equipment necessary for the proper installation, maintenance, inspection, monitoring, reporting, and removal (where applicable) of erosion prevention and control measures and to cause compliance with the Virginia General Permit to Discharge Stormwater Under the National Pollution Discharge Elimination System (NPDES) from Construction Activities (Permit No. VAR10), for any land disturbance or construction activity of one (1) acre or more, under this Section 02276. B. All excavations shall be in conformity with the lines, grades, and cross sections shown on the Drawings or established by the Engineer. C. It is the intent of this Specification that the Contractor conducts the construction activities in such a manner that erosion of disturbed areas and off site sedimentation be absolutely minimized. tow D. All work under this Contract shall be done in conformance with and subject to the limitations of the Virginia Erosion and Sediment Control Law, Regulations and Certification Regulations, as adopted in the Code of Virginia Title 10 -1, Chapter 5, Article 4 and Sections 4VAC30 -50 and 4VAC50 -50 of the Virginia Administration Code. E. The following excerpts from the regulations are particularly important: OM 1. Permanent or temporary soils stabilization shall be applied to denuded areas within seven days after final grade is reached on any portion of the site. 2. Temporary soil stabilization shall be applied within seven days to denuded areas that may not be at final grade but will remain dormant for longer than 30 days, but less than one year. 3. Permanent stabilization shall be applied to areas that are to be left dormant for more than one year. F. Due to the nature of the work required by this Contract, it is anticipated that the location and tin nature of the erosion and sedimentation control devices will be adjusted on several occasions to reflect the current phase of construction. The construction schedule adopted by the Contractor will impact the placement and need for specific devices required for the control of erosion. The Contractor shall develop and implement such additional techniques 31037102276.doc:12 -15 -04 02276.doc -1 INFLUENT SCREEN BUILDING �• RWSA as may be required to minimize erosion and off -site sedimentation. The location and extent of erosion and sedimentation control devices shall be revised at each phase of construction that results in a change in either the quantity or direction of surface runoff from constructed areas. All deviations from the erosion and sedimentation control provisions shown on the Drawings shall have the prior acceptance of the Engineer. 1.02 RELATED WORK SPECIFIED ELSEWHERE A. Section 02100 - Clearing, Grubbing, and Site Preparation oft B. Section 02200 — Earthwork C. Section 02500 — Surface Restoration C. Section 02910 - Final Grading and Landscaping 1.03 REFERENCE SPECIFICATIONS, CODES AND STANDARDS A. Without limiting the generality of other requirements of these specifications, all work hereunder shall conform to the applicable requirements of the referenced portions of the following documents, to the extent that the requirements therein are not in conflict with the provisions of this Section. 1. Code of Virginia, Title 10.1, Chapter 5, Article 4 2. Virginia Erosion and Sediment Control Handbook, latest edition 3. Virginia General Permit to Discharge Stormwater under the National Pollution Discharge Elimination System (Permit No. VAR10), for any land disturbance or construction activity of one (1) acre or more. B. See Specification Section 01090 - Reference Standards. 1.04 REGULATORY COMPLIANCE A. Land disturbance activities are not authorized to begin until after all required erosion and sediment control permits are obtained from the United States and the Commonwealth of Virginia. Contractor is the Co- Primary Permittee and Operator under the provisions of the NPDES Permit. As such, the Contractor will be required to sign certain certifications as described in the Permit. Contractor shall comply with requirements specified in the Contract Documents or by the Engineer. Contractor shall also comply with all other laws, rules, regulations, ordinances and requirements concerning soil erosion and sediment control established in the United States and the Commonwealth of Virginia. The following documents and the documents referenced therein define the regulatory requirements for this ,,,, Section 02276. 1. NPDES PERMIT: The Virginia National Discharge Elimination System (NPDES) General Permit for Storm Water Discharges Associated with Construction Activity governs land disturbance or construction activities of one (1) acre or more. On applicable sites, Contractor is responsible for complying with terms and conditions of this permit. VIII 31037102276.doc:12 -15 -04 02276.doc -2 INFLUENT SCREEN BUILDING RWSA rr 2. Virginia Erosion and Sediment Control Handbook: Contractor shall follow Practices and Standards of the Virginia Erosion and Sediment Control Handbook (VESCH), latest edition. 3. SWP3: When a Storm Water Pollution Prevention Plan (SWP3) is provided in the Contract Documents, the Contractor shall follow the practices described in the SWP3. (See the Appendix for the SWP3, if applicable). 1.05 SUBMITTALS A. Prior to the start of the work, the Contractor shall prepare and submit a plan for applying the temporary and permanent erosion and siltation control measures as shown on the Owners State Land Quality approved Erosion and Sediment Control Plan. Construction work shall not commence until the schedule of work and the methods of operations have been reviewed and approved. B. In accordance with the procedures and requirements set forth in the General Conditions Division 1 and Section 01300 - Submittals, the Contractor shall submit the following: 1. Name and location of all material suppliers. 2. Certificate of compliance with the standards specified above for each source of each material. Iwo 3. List of disposal sites for waste and unsuitable materials and all required permits for use of those sites. 1.06 EROSION AND SEDIMENTATION CONTROL DEVICES A. The following erosion and sedimentation control devices shall be incorporated into the work. Other devices, as necessary and acceptable to the Engineer shall be installed as required. 1. Temporary Sediment Traps shall be constructed at the locations shown on the Drawings, at the termination of all Temporary Diversions diverting sediment laden runoff, and at other locations indicated by the Engineer. Temporary Sediment Traps shall be constructed by excavating the appropriate size rectangular basin and constructing a rock -fill dam on the discharge end to form a sediment trap. "' Temporary Sediment Traps shall be spaced to limit the maximum tributary drainage area to Tess than or equal to 5 acres. Temporary Sediment Traps shall be designed, installed and maintained in accordance with the requirements of Section 3.13 of the r•w VESCH. 2. Temporary Diversions Dikes shall be constructed at the locations shown on the Drawings, and at other locations indicated by the Engineer. Dimensions shall be as shown on the Drawings. All Diversions transporting sediment -laden runoff shall terminate in Temporary Sediment Basins. Temporary Diversion Dikes shall be designed, installed and maintained in accordance with the requirements of Section ` 3.09 of the VESCH. 31037102276.doc:12 -15 -04 02276.doc -3 INFLUENT SCREEN BUILDING ` Wm RWSA 3. Silt Fence shall be constructed at the locations shown on the Drawings, and at other locations indicated by the Engineer. Silt Fence shall not be installed across streams, ditches, or waterways. Silt Fence shall be designed, installed and maintained in accordance with the requirements of Section 3.05 of the VESCH. 4. Stone Filters shall be constructed at the locations shown on the Drawings, and at other locations indicated by the Engineer. Dimensions shall be as shown on the Drawings. v as 5. Rock Check Dams shall be constructed at the locations shown on the Drawings, and at other locations indicated by the Engineer. Rock Check Dams shall be designed, installed and maintained in accordance with the requirements of Section 3.20 of the .o; VESCH. 6. Storm Drain Inlet Protection shall be constructed at the locations shown on the Drawings, and at other locations indicated by the Engineer. Inlet Protection shall be designed, installed and maintained in accordance with the requirements of Section 3.07 of the VESCH. 7. Culvert Inlet Protection shall be constructed at the locations shown on the Drawings, and at other locations indicated by the Engineer. Culvert Inlet Protection shall be designed, installed and maintained in accordance with the requirements of Section 3.08 of the VESCH. 8. Temporary and Permanent Channels shall be installed at the locations shown on the tw Drawings, and at other locations indicated by the Engineer. Channels, and Channel Linings, shall be designed, installed and maintained in accordance with the requirements of Section 3.17 of the VESCH. 9. Temporary Slope Drains shall be installed at the locations shown on the Drawings, and at other locations indicated by the Engineer. Temporary Slope Drains shall be designed, installed and maintained in accordance with the requirements of Section 3.15 of the VESCH. 10. Construction Entrances shall be located at points where vehicles enter and leave a construction site, or at other locations indicated by the Engineer. Construction Entrances shall be designed, installed and maintained in accordance with the requirements of Section 3.02 of the VESCH. 1.07 GUARANTEE +.. A. All restoration and revegetation work shall be subject to the one -year guarantee period of the Contract as specified in the General Conditions. PART 2 -- MATERIALS 2.01 MATERIALS A. Materials for use in erosion and sedimentation control devices shall be in accordance with the VESCH. 31037102276.doc:12 -15 -04 02276.doc -4 INFLUENT SCREEN BUILDING RWSA t. rw 2.02 TEMPORARY SEDIMENT TRAPS A. Temporary sediment basins shall be constructed as shown on the Contract Drawings and as specified herein. The temporary sediment basins shall be constructed and maintained in accordance with the Maintenance paragraph, and Section 3.13 of the VESCH, to the satisfaction of the Engineer until a vegetative ground cover has been established. The cost of the temporary sediment basins shall include the excavation, grading, stone for erosion control, washed stone, geotextile, etc. and all maintenance activities required. 2.03 TEMPORARY DIVERSIONS A. Temporary Diversions shall be constructed as shown on the Contract Drawings and as specified herein. Temporary Diversions shall be installed and maintained in accordance with the Maintenance paragraph, and Section 3.09 of the VESCH, to the satisfaction of the Engineer until the site has been stabilized. The cost of Temporary Diversions shall include the excavation and all maintenance and restoration activities required. 2.04 SILT FENCE A. Silt Fence shall be a woven geotextile filter fabric made specifically for sediment control. Filter fabric shall not rot when buried and shall resist attack from soil chemicals, alkalies and acids in the pH range from 2 to 13, and shall resist damage due to prolonged ultraviolet exposure. Filter fabric shall be Type FX -11, as manufactured by Carthage Mills, Geotex 910SC as manufactured by Synthetic Industries, Inc., Amoco 2130 as manufactured by Amoco Fabrics & Fibers Co., or equal. B. Filter fabric for the silt fence shall have the following minimum properties: Value Test Method 00. Grab Tensile Strength 100 lbs ASTM D 4632 Grab Elongation 15% ASTM D 4632 Trapezoid Tear Strength 50 lbs ASTM D 4533 Mullen Burst Strength 265 lbs ASTM D 3786 rr Puncture Strength 58 lbs ASTM D 4833 �•• Retained Strength (500 hrs. accelerated UV exposure) 80% ASTM D 4355 Filtration Efficiency 75% VTM -51 Flow Rate 10 gal /min /ft ASTM -D4491 Height 36 inches Imo 31037\02276.doc:12 -15 -04 02276.doc -5 INFLUENT SCREEN BUILDING ,.F RWSA C. Posts for silt fence shall be steel and shall have the following properties: ASTM Designation: ASTM A702 Length: 5 -Feet Long (T -Type) Weight: 1.25 # /Foot (min.) Area of Anchor Plate: 14 Sq. In. Note: Five (T) Fasteners shall be furnished with each post. D. Wire Fabric for the silt fence shall have the following properties: Wire Fabric Designation: 832 -12 -10 -12.5 Class 1 .► Designation: ASTM A116 Width: 32" Number of Line Wires: 8 ow Stay Wire Spacing: 12" Line and Stay Wires: 12.5 Ga. Top and Bottom Wires: 10 Ga. Wire Coating: ASTM Class 1 Zinc Coating Silt Fence shall be installed and maintained in accordance with the Maintenance paragraph, and Section 3.05 of the VESCH, to the satisfaction of the Engineer until the site has been "" stabilized. The cost of Silt Fence shall include the fabric, posts, wire fabric, excavation and all maintenance and restoration activities required. 2.05 STONE FOR EROSION CONTROL A. The Contractor shall place Stone for Erosion Control as shown on the Drawings, as specified herein and as specified in Section 414 of the VDOT Standard Specifications. The Stone for Erosion Control shall be Class Al, or as shown on the Drawings. 2.06 RIPRAP A. The Contractor shall place rip rap as shown on the Drawings and as specified in Section 868 of the VDOT Standard specifications for plain Riprap. The stone for riprap shalt consist of "im field stone or rough unhewn quarry stone. The stone shall be sound, tough, dense, and resistant to the action of air and water. Neither the width nor thickness of individual stones shall be less than one -third their length. The riprap shall be Class II as specified in the VDOT Standard Specifications, Section 414 - Riprap, unless otherwise shown on the Drawings. w 2.07 STRAW WITH NET TEMPORARY ROLLED EROSION CONTROL MAT (RECM) A. The Contractor shall place straw with net temporary channel and slope RECM as shown on MIK the Drawings. The mat shall consist of clean wheat straw from agricultural crops made into a knitted straw mat that is machine assembled. The straw shall be evenly distributed throughout the mat. The mat shall be covered with a photodegradable synthetic mesh attached to the straw with degradable thread. 31037102276.doc:12 -15 -04 02276.doc -6 INFLUENT SCREEN BUILDING RWSA B. The Contractor shall place the straw with net temporary channel and slope RECM where directed immediately after the channel or slope has been properly graded and prepared, „ fertilized, and seeded. If the mat is of single net construction, the netting shall be on top with the straw in contact with the soil. C. The Contractor will immediately repair or replaced any section of straw with net temporary channel and slope RECM which is not functioning properly or has been damaged in anyway until a stable growth of grass has been established. ""' D. Straw with net RECM shall be North American Green S150, American Excelsior Co. Curlex I, Contech SFB1, or equal with a minimum bare soil shear stress value of 1.5 Ib /ft wr 2.08 CURLED WOOD OR COCONUT FIBER ROLLED EROSION CONTROL MAT (RECM) A. The Contractor shall place curled wood or coconut fiber channel and slope RECM in .,. channels or on slopes as shown on the Drawings. The mat shall consist of machine - produced mat of curled wood excelsior or coconut fiber with a majority of the fibers 6 inches or longer with consistent thickness and the fibers evenly distributed over the entire area of the mat. The top of the mat shall be covered with a biodegradable synthetic mesh. The mesh shall be attached to the curled wood excelsior or coconut fiber with photodegradable synthetic yarn. B. The Contractor shall place the curled wood or coconut fiber channel and slope RECM where directed immediately after the channel or slope has been properly graded and prepared, fertilized, and seeded. If the mat is of single net construction, the mesh shall be on top with the fibers in contact with the soil. C. The Contractor will immediately repair or replace any section of curled wood or coconut fiber ... RECM which is not functioning properly or has been damaged in any way until a stable growth of grass has been established. D. Curled wood or coconut fiber RECM shall be American Excelsior Curlex II, North American Green C125, Contech EFB4 or equal matting with a minimum bare soil shear stress value of 2.0 I b /ft 2.09 SYNTHETIC TURF REINFORCEMENT MAT (TRM) A. The Contractor shall place synthetic channel and slope TRM in channel or on slopes as shown on the Drawings. The mat shall consist of entangled nylon, polypropylene or polyester monofilaments mechanically joined at their intersections forming a three dimensional structure. The mat shall be crush - resistant, pliable, water - permeable, and 014 highly resistant to chemical and environmental degradation. B. The Contractor shall place the synthetic TRM where directed immediately after the channel or slope has been properly graded and prepared. C. After the TRM has been placed, the area shall be properly fertilized and seeded as specified allowing the fertilizer and seeds to drop through the net. 31037102276.doc:12 -15 -04 02276.doc -7 INFLUENT SCREEN BUILDING RWSA INN D. The Contractor will immediately repair or replace any section of TRM which is not functioning properly or has been damaged in any way until a stable growth of grass has been .. established. E. Synthetic TRM shall be Enkamat 7020 as manufactured by Colbond Geosynthetics, Synthetic Industries Landlock Erosion Mat TRM 1060, TH8 as manufactured by TC Mirafi, or equal matting with a minimum Tong -term vegetated shear stress value of 5.0 Ib /ft 2.10 TEMPORARY SLOPE DRAINS eft A. Temporary slope drains shall be constructed as shown on the Drawings and as specified herein. The temporary slope drains shall be constructed and maintained in accordance with the Maintenance paragraph of Section 3.15 of the VESCH to the satisfaction of the Engineer until the site has been stabilized. The cost of the temporary slope drains shall include the piping, earthwork, stone for erosion control, and all maintenance activities required. 2.11 CONSTRUCTION ENTRANCES o ,,,, A. Construction entrances shall be constructed as shown on the Drawings and as specified herein. Construction entrances shall be maintained in accordance with the Maintenance paragraph of Section 3.02 of the VESCH to the satisfaction of the Engineer until the site has been stabilized. The cost of construction entrances shall include the gravel and all maintenance activities required. 2.12 TEMPORARY SOIL STABILIZER A. The temporary agent for soil erosion control shall consist of an especially prepared highly concentrated powder which, when mixed with water, forms a thick liquid such as "Enviroseal 2001" by Enviroseal Corporation, "Terra Control" by Quattro Environmental, Inc., or "CHEM- CRETE ECO -110" by International CHEM -CRETE Corporation, and having no growth or germination inhibiting factors. The agent shall be used for hydroseeding grass seed in mit combination with other approved amendments resulting in a highly viscous slurry which, when sprayed directly on the soil, forms a gelatinous crust. PART 3 -- EXECUTION 3.01 INSTALLATION AND MAINTENANCE A. Erosion and sedimentation control devices shall be established prior to or concurrent with the clearing operations in a given area. Where such practice is not feasible, the erosion and sedimentation control device(s) shall be established immediately following completion of the clearing operation. •• B. The Contractor shall furnish the labor, materials and equipment required for routine maintenance of all erosion and sedimentation control devices. Maintenance shall be scheduled as required for a particular device to maintain the removal efficiency and intent of the device. Maintenance shall include but not be limited to 1) the removal and satisfactory disposal of accumulated sediment from traps or silt barriers and 2) replacement of filter fabrics used for silt fences and stone used in temporary sediment traps, stone filters, construction entrances, etc.. Sediment removed from erosion and sedimentation control 31037102276.doc:12 -15 -04 02276.doc -8 INFLUENT SCREEN BUILDING NMI RWSA devices shall be disposed of in locations that will not result in off site sedimentation as acceptable to the Engineer, at no additional cost to the Owner. C. The Contractor shall provide temporary sedimentation traps at all locations shown on the Contract Drawings and for the settling of water pumped from the excavations or intercepted .. by drainage ditches for keeping water out of the excavations or to protect existing structures. The Contractor shall remove accumulated sediment from the traps as necessary to maintain their effectiveness or as indicated by the Engineer. Sediment material removed from the traps shall be disposed by the Contractor in locations that will not result in off -site sedimentation as acceptable to the Engineer, at no additional cost to the Owner. 1. Inspect temporary sediment traps after each period of significant rainfall. Remove sediment and restore the trap to its original dimensions when the sediment has accumulated to one -half the design depth of the trap. Place the sediment that is removed in a designated disposal area and replace the contaminated part of the .. gravel facing. 2. Check the structure for damage from erosion or piping. Periodically check the depth of the spillway to ensure it is a minimum of 1.5 ft. below the low point of the embankment. Immediately fill any settlement of the embankment to slightly above design grade. Any riprap displaced from the spillway must be replaced immediately. 3. After all sediment - producing areas have been permanently stabilized, remove the structure and all unstable sediment. Smooth the area to blend with the adjoining areas and stabilize properly. D. The Contractor shall provide temporary diversions at all locations noted on the Contract Drawings. All temporary diversions shall outlet at a temporary sediment trap or other appropriate structure. 11116 1. Inspect temporary diversions once a week and after every rainfall. Immediately remove sediment form the flow area and repair the diversion ridge. Carefully check outlets and make timely repairs as needed. When the area protected is permanently • stabilized, remove the ridge and the channel to blend with the natural ground level and appropriately stabilize it. E. Silt fence shall be erected as shown on the Drawings and specified herein. Silt fence shall "` be erected and maintained to the satisfaction of the Engineer until a vegetative ground cover has been established. Replacement of the filter fabric, if required by the Engineer, will be at the Contractor's expense. .. 1. Silt fence shall be erected around all catch basins which are located downstream from any construction work. Should any catch basins be indicated to be relocated or .0 modified, silt fence shall be utilized until work is completed on the catch basins. Upon completion of the modification, the area shall be rough graded, as shown on the Drawings, until the end of the project, at which time final grading shall occur. 2. Inspect silt fence at least once a week and after each rainfall. Make any required repairs immediately. 31037102276.doc:12 -15 -04 02276.doc -9 INFLUENT SCREEN BUILDING .. RWSA 3. Should the fabric of a silt fence collapse, tear, decompose or become in- effective, replace it promptly. INN 4. Remove sediment deposits as necessary to provide adequate storage volume for the next rain and to reduce pressure on the fence. Take care to avoid undermining the fence during cleanout. 5. Remove all fencing materials and unstable sediment deposits and bring the area to grade and stabilize it after the contributing drainage area has been properly stabilized. Removal of any silt fence shall be permitted only with the prior approval of the Engineer, or the local governing agency. F. Riprap shall be graded so that the smaller stones are uniformly distributed through the mass. The Contractor may place the stone by mechanical methods, augmented by hand placing where necessary or ordered by the Engineer. The placed riprap shall form a properly r.w graded, dense, neat layer of stone. The placed riprap shall have a minimum depth of 24 inches. Type II Separator Geotextile, as specified in Section 02274 — Geosythetics, shall be used under all riprap unless otherwise noted. G. Riprap and stone for erosion control shall be dumped and placed in such manner that the larger rock fragments are uniformly distributed throughout the rock mass and the smaller fragments fill the voids between the larger fragments. Rearranging of individual stones by equipment or by hand shall only be required to the extent necessary to secure the results specified above, to protect structures from damage when rock material is placed against the structures, or to protect the underlying Separator Geotextile from damage during installation. W. 1. Inspect gravel and riprap filter berm basins after each period of significant rainfall. Remove sediment and restore the basin to its original dimensions when the ..� sediment has accumulated to one -half the design depth of the trap. Place the sediment that is removed in a designated disposal area and replace the contaminated part of the gravel facing. 2. Check the structure for damage from erosion or piping. Any stone or riprap displaced from the berm must be replaced immediately. 3. After all sediment - producing areas have been permanently stabilized, remove the structure and all unstable sediment. Smooth the area to blend with the adjoining areas and stabilize properly. w H. Engineer may direct the Contractor to place Straw with Net, Curled Wood or Coconut Fiber RECM's and Synthetic TRM's in permanent channels or on slopes at other locations not i"' shown on Drawings. 1. All temporary and permanent channel and slope lining RECM's and TRM's shall be .. unrolled in the ditch in the direction of the flow of water. Temporary linings shall overlap the buried end of the downstream blanket by a minimum of 6 inches. Permanent linings shall overlap a minimum of 3 feet. All anchor and transverse trenches shall be a minimum of 12 inches deep. All mat shall be stapled as per manufacturer's specifications. 31037102276.doc:12 -15 -04 02276.doc -10 INFLUENT SCREEN BUILDING „� RWSA UMW rr 2. During the establishment period, check grass, RECM and TRM -lined channels after every rainfall event. For grass -lined channel once grass is established, check tam periodically and after every heavy rainfall event. Immediately make repairs. It is particularly important to check the channel outlet and all road crossings for bank stability and evidence of piping and scour holes. Give special attention to the outlet and inlet sections and other points where concentrated flow enters. Remove all significant sediment accumulations to maintain the designed carrying capacity. Keep the grass in a healthy, vigorous condition at all times. I. The Contractor shall provide temporary slope drains at all location noted on the Contract Drawings, and at other locations as may be directed by the Engineer. 1. Inspect the temporary slope drain and supporting diversion after every rainfall event and promptly make any necessary repairs. When the protected area has been permanently stabilized, temporary measures may be removed, materials disposed of „ properly, and all disturbed areas stabilized appropriately. J. The Contractor shall provide construction entrances at all locations noted on the Contract Drawings, and at all other locations as may be directed by the Engineer. 1. Maintain the gravel pad in a condition to prevent mud or sediment from leaving the construction site. This may require periodic topdressing with 2 -inch stone. After each rainfall, inspect each construction entrance and clean out as necessary. Immediately remove all objectionable materials spilled, washed, or tracked onto public roadways. r. K. The Contractor shall provide temporary or permanent ground cover adequate to restrain erosion on all disturbed areas that will be left unworked for periods exceeding 15 working or 30 calendar days. 1. Reseed and mulch temporary seeding areas where seedling emergence is poor, or where erosion occurs, as soon as possible. Do not mow. Protect from traffic as much as possible. 2. Generally, a stand of vegetation cannot be determined to be fully established until 1° soil cover has been maintained for one full year from planting. Inspect seeded areas for failure and make necessary repairs and reseedings within the same season, if possible. 3. Reseeding — If a stand has inadequate cover, re- evaluate choice of plant materials and quantities of lime and fertilizer. Re- establish the stand after seedbed preparation or over -seed the stand. Consider seeding temporary, annual species if the time of year is not appropriate for permanent seeding. ,.. 4. If vegetation fails to grow, soil must be tested to determine if acidity or nutrient imbalance is responsible. Imo 31037102276.doc:12 -15 -04 02276.doc -11 INFLUENT SCREEN BUILDING RWSA v Pro 5. Fertilization — On the typical disturbed site, full establishment usually requires refertilization in the second growing season. Fine turf requires annual maintenance fertilization (See Section 3.31 of the VESCH). Use soil tests if possible or follow the guidelines given for the specific seeding mixture (See Tables 3.32 -A through 3.32 -D, VESCH) L. Additional Requirements 1. All storm sewer piping shall be blocked at the end of every working day until the inlet is constructed above grade. 2. All streets around the construction area shall be scraped as necessary to prevent accumulation of dirt and debris. 3. The Contractor shall provide adequate means to prevent any sediment from entering ... any storm drains, curb inlets (curb inlet filter box), ditches, streams, or bodies of water downstream of any area disturbed by construction. Excavation materials shall be placed upstream of any trench or other excavation to prevent sedimentation of offsite areas. In areas where a natural buffer area exists between the work area and the closest stream or water course, this area shall not be disturbed. 4. The Engineer may direct the Contractor to place any additional sediment and erosion i "' control devices at other locations not shown on the Drawings. 3.02 INSPECTIONS AND MAINTENANCE A. The Contractor shall designate a Certified Responsible Land Disturber to perform inspections required by this Section. The following areas are to be inspected and imp maintenance performed, if needed, at least once every 7 calendar days and within 24 hours of a rainfall event that has a precipitation of 1/2 inch or greater. 1. Disturbed areas of the construction site that have not undergone final stabilization 2. Erosion and sediment control structures 3. All locations where vehicles enter or exit the site 4. Material storage and construction laydown areas that are exposed to precipitation and have not been finally stabilized B. When a Storm Water Pollution Prevention Plan (SWP3) is provided in the Contract Documents, the Responsible Land Disturber shall follow the practices inspection and maintenance requirements described in the SWP3. (See the Appendix for the SWP3, if applicable). All appropriate records required by the SWP3 shall be maintained on site. ..1 C. Immediate action will be taken to correct deficiencies to BMP's. The State reserves the right to stop all construction activities not related to maintaining BMP's until such deficiencies are repaired. 31037102276.doc:12 -15 -04 02276.doc -12 INFLUENT SCREEN BUILDING , RWSA D. In areas that have been finally stabilized, inspections and, if necessary, maintenance by Contractor will occur at least once per month for the duration of the contract or project, whichever is longer. E. During inspections the following will be observed and appropriate maintenance procedures taken: 1. The conformance to specifications and current condition of all erosion and sediment control structures 2. The effectiveness and operational success of all erosion and sediment control measures ti. 3. The presence of sediments or other pollutants in storm water runoff at all runoff discharge points 4. If reasonably accessible, the presence of sediments or other pollutants in receiving waters 5. Evidence of off -site tracking at all locations where vehicles enter or exit the site E. An inspection checklist is included in the SWP3, if required, and is attached at the Appendix. This checklist must be completed during each inspection, dated, and signed by the Qualified Person conducting the inspection. Completed inspection checklist shall be kept on -site with the Contract Documents and submitted to the Engineer on a monthly basis. The Contractor will repair deficiencies within 24 hours of inspection. 3.03 MONITORING AND REPORTING A. Monitoring: The Contractor shall be responsible for the implementation of the Maintenance and Inspection Procedures as written by the Engineer. The implementation must comply with guidelines as set forth in Part 1 Section B: Minimum Monitoring and Reporting Requirements shall be those of the Virginia General Permit to Discharge Stormwater under the National Pollution Discharge Elimination System, VDEQ Permit No. VAR10, or most recent version. B. Reporting: The Contractor shall prepare and submit a summary of the monitoring results to the Engineer, the Designer and the VDEQ as required in the NPDES permit. The State y " reserves the right to use its own resources to duplicate monitoring and verify the work required by the Contractor in this section. 31037102276.doc:12 -15 -04 02276.doc -13 INFLUENT SCREEN BUILDING .., RWSA 3.04 REMOVAL OF TEMPORARY SEDIMENT CONTROL STRUCTURES A. At such time that temporary erosion and control structures are no longer required under this item, the Contractor shall notify the Engineer of its intent and schedule for the removal of the temporary structures, and obtain the Engineer's approval in writing prior to removal. Once the Contractor has received such written approval from the Engineer, the Contractor shall remove, as approved, the temporary structures and all sediments accumulated at the removed structure shall be returned upgrade. In areas where temporary control structures are removed, the site shall be left in a condition that will restore original drainage. Such areas shall be evenly graded and seeded as specified in Section 02910 - Final Grading and Landscaping. NW - END OF SECTION - N. 31037102276.doc:12 -15 -04 02276.doc -14 INFLUENT SCREEN BUILDING RWSA SECTION 02910 FINAL GRADING AND LANDSCAPING PART 1 -- GENERAL 1.01 THE REQUIREMENT A. Furnish all labor, equipment, and materials necessary for final grading, topsoiling, seeding, and miscellaneous site work not included under other Sections, but required to complete the work as shown on the Drawings and specified herein. Under this Section, all areas of the project site disturbed by excavation, materials storage, temporary roads, etc., shall be reseeded as specified herein. 1.02 RELATED WORK SPECIFIED ELSEWHERE A. Section 02276 - Erosion and Sedimentation Control B. Section 02500 - Surface Restoration 1.03 SUBMITTALS A. Submit the following in accordance with Section 01300 - Submittals. 1. Product Data 2. Certification of all materials 3. Three (3) copies of composition and germination certification and of test results for grass seed. PART 2 -- PRODUCTS 2.01 CONTRACTOR'S RESPONSIBILITIES A. Furnish and submit certification for the materials used as specified in the General Conditions, Division 1 and Division 2. 2.02 TOPSOIL ..► A. Upon completion and approval of the rough grading, the Contractor shall place the topsoil over all areas disturbed during construction under any contract except those areas which will be paved, graveled or rip rapped. Topsoil shall not be placed in a frozen or muddy condition �,. and shall contain no toxic materials harmful to grass growth. Topsoil shall be as defined under Section 02200 - Earthwork. 2.03 WATER A. Water shall be furnished to the Contractor by the Owner from existing facilities as directed by the Engineer. 31037102910.DOC:12 -15 -04 02910.DOC -1 INFLUENT SCREEN BUILDING RWSA B. The Contractor shall furnish all hoses and connections necessary to complete the landscaping work. 2.04 FERTILIZER A. Fertilizer shall be a complete commercial fertilizer with components derived from commercial sources. Fertilizer analysis shall be determined from field soil sampling in appropriate number taken by the Contractor and analyzed by the Virginia Department of Agriculture or "" other independent laboratory. Contractor shall furnish fertilizer in accordance with the recommendations of the Virginia Department of Agriculture. B. One - quarter of the Nitrogen shall be in the form of nitrates, one - quarter in the form of ammonia salts, and one -half in the form of natural organic Nitrogen. Available Phosphoric Acid shall be free from superphosphate, bone, or tankage. Potash shall be Sulphate of r.., Potash. Elements shall conform to the standards of Association of Official Agricultural Chemists. C. Fertilizer shall be delivered in standard size bags marked with the weight, analysis of contents, and the name of the manufacturer. Fertilizer shall be stored in weatherproof storage areas and in such a manner that its effectiveness will not be impaired. `" 2.05 LIME A. At least 50% shall pass a No. 200 U.S.S. mesh sieve. At least 90% shall pass a No. 100 U.S.S. mesh sieve and 100% shall pass a No. 10 U.S.S. mesh sieve. Total carbonates shall not be less than 80% or 44.8% Calcium Oxide equivalent. For the purpose of calculation, total carbonates shall be considered as Calcium Carbonate. 2.06 GRASS SEED A. The Contractor shall furnish the kinds and amounts of seed to be seeded in all areas disturbed by the construction work. All seed shall be labeled to show that it meets the requirements of the Virginia Seed Law. All seed must have been tested within six (6) months immediately preceding the planting of such material on the job. B. The inoculant for treating legume seed shall be a pure culture of nitrogen- fixing bacteria prepared specifically for the species. Inoculants shall not be used later than the date indicated on the container. The quality of the seed shall conform to the following: Minimum Minimum Maximum taw Seed Purity Germination Weed Seed Type ( %) ( %) ( %) Kentucky Bluegrass 98 90 1.00 Perennial Ryegrass 98 85 0.10 Annual Ryegrass 98 85 0.10 Winter Rye 98 85 0.25 German Millet 98 85 0.50 Weeping Lovegrass 98 85 0.50 31037102910.DOC:12 -15 -04 02910.DOC -2 INFLUENT SCREEN BUILDING .�. RWSA N. C. Scarified Lespedeza may contain 20% hard seed and unscarified 50% hard seed. Seed containing prohibited noxious weed seed shall not be accepted. Seed shall be in conformance with Virginia Seed Law restrictions for restricted noxious weeds. D. Seed mixtures to be used on the project shall be as follows: ` P - 190 # /acre Kentucky 31 Tall Fescue, 5# /acre Perennial Ryegrass, 5# /acre Kentucky Bluegrass TW - 50# /acre Annual Ryegrass, 50# /acre Cereal (Winter) Rye TS - 50# /acre German Millet TSp - 100 # /acre Annual Ryegrass t ,,,, Note: P - Permanent Seeding TW - Temporary Winter Seeding TS - Temporary Summer Seeding TSp - Temporary Spring E. On cut and fill slopes 2:1 or steeper add 20# /acre of Weeping Lovegrass to the P seed mixture. Sericea Lespedeza seed shall be scarified for spring plantings and unscarified for fall plantings. 2.07 WOOD CELLULOSE FIBER MULCH A. For use in hydroseeding grass seed in combination with fertilizers and other approved additions, shall consist of especially prepared wood cellulose fibers such as "Conwed ", �,. "Silva- Fiber ", or equal, and have no growth or germination inhibiting factors, and be dyed green. B. The wood cellulose fiber shall have the additional characteristic of dispersing rapidly in water romi to form a homogeneous slurry and remain in such state when agitated in the hydraulic mulching unit, or adequate equal, with the specified materials. C. When applied, the wood cellulose fiber with additives will form an absorptive mat but not a plant inhibiting membrane, which will allow moisture, natural or mechanical, to percolate into underlying soil. D. The mulch shall be supplied, compressed in packages containing 50 pounds of material having an equilibrium air dry moisture content at time of manufacture of 12% plus or minus r•• 2 %. Wood cellulose fiber mulch shall be stored in a weatherproof storage area and in such a manner that effectiveness will not be impaired. 2.08 STRAW MULCH A. Straw used for mulch shall be small grain hay. Hay shall be undamaged, air dry, threshed straw, free of undesirable weed seed. Straw mulch is not required for seeded areas treated with a temporary soil stabilizer. 31037102910.DOC:12 -15 -04 02910.DOC -3 INFLUENT SCREEN BUILDING ,�„ RWSA 2.09 TEMPORARY SOIL STABILIZER ,,,, A. The temporary agent for soil erosion control shall consist of an especially prepared highly concentrated powder which, when mixed with water, forms a thick liquid such as "Enviroseal 2001" by Enviroseal Corporation, "Terra Control" by Quattro Environmental, Inc., or "CHEM- CRETE ECO -110" by International CHEM -CRETE Corporation, and having no growth or germination inhibiting factors. The agent shall be used for hydroseeding grass seed in combination with other approved amendments resulting in a highly viscous slurry which, when sprayed directly on the soil, forms a gelatinous crust. 2.10 DITCH EROSION RETENTION BLANKET A. The blanket shall be as specified in Section 02276 - Erosion and Sedimentation Control. 2.11 RIPRAP AND HERBICIDES A. Furnish and install sufficient quantity of landscape gravel or riprap to cover over the ground to a minimum 4 -inch depth for gravel and 24 -inch depth for riprap, unless otherwise noted, diem or indicated on the Drawings. Also furnish and apply an approved herbicide to the subgrade surface just prior to installing the landscape gravel or riprap. B. During placing, the stone shall be graded so that the smaller stones are uniformly distributed through the mass. The Contractor may place the stone by mechanical methods, augmented by hand placing where necessary or ordered by the Engineer. The placed riprap shall form a properly graded, dense, neat layer of stone. C. All topsoil and vegetative matter shall be removed from the subgrade surfaces prior to the application of the weed killer (herbicide) and to the placement of landscape gravel or riprap. �.. Apply commercial -type herbicide as preemergence control of miscellaneous grasses and broadleaf weeds in granular or liquid form such as "Treflan ", "Dymid ", or equal. Methods and rates of application shall be in strict compliance to manufacturer's directions and acceptable to the Engineer. D. The herbicide selected shall be safe for use around ornamental plantings, have long- lasting weed control, and shall be resistant to leaching away under excessive rainfall. SW E. A second application of the herbicide shall be made on the surface of the landscape gravel or riprap sometime after the first six (6) months, but not later than 12- months. Same methods and rates apply as specified previously. us PART 3 -- EXECUTION 3.01 GRADING A. After approval of the rough grading, the Contractor shall commence his preparations of the subgrade for the various major conditions of the work as follows: ory 1. Bare soil for riprap area at subgrade (24- inches below final grade, or as directed by the Engineer). 31037102910.DOC:12 -15 -04 02910.DOC -4 INFLUENT SCREEN BUILDING �,, RWSA w 2. Topsoil for lawn and road shoulder seed area - scarify 2 -inch depth of subgrade (4- inches below final grade) prior to placing topsoil. B. Final surface grading of the topsoiled, landscape graveled, and riprapped areas shall be mechanically raked or hand raked to an even finished surface alignment. 3.02 TOPSOIL A. Topsoil shall be spread in place for quantity required for lawn and road shoulder seed areas at 4 -inch consolidated depth, and sufficient quantity for certain plant beds and backfill for shrubs and trees as specified. 3.03 SEEDBED PREPARATION A. Contractor shall prepare all areas to receive temporary or permanent seeding measures prior to planting. B. Topsoil shall be placed in areas to be seeded and roughened with tracked equipment or other suitable measures. Slopes steeper than 3:1 may be roughened by grooving, furrowing, tracking, or stairstep grading. Slopes flatter than 3:1 should be grooved by disking, harrowing, raking, operating planting equipment on the contour. C. Soil amendments including, but not limited to, lime and fertilizer shall be spread as necessary, and at the rates specified in this Section. Seeding shall be as per the type and rates specified in this Section. Seed shall be broadcast as soon as possible following roughening, before surface has been sealed by rainfall. 3.04 HYDROSEEDING AND GRASS A. The Contractor shall grow a stand of grass by hydroseeding method on all disturbed areas. The Contractor shall be responsible for the satisfactory growth of grass throughout the period of the one -year guarantee. B. The Contractor's work shall include the preparation of the topsoil and bare soil seed bed, application of fertilizer, limestone, mulching, inoculant, temporary soil stabilizer, watering, and all other operations necessary to provide a satisfactory growth of sod at the end of the one -year maintenance period. Areas without satisfactory sod at the end of one (1) year shall be replanted until satisfactory growth is obtained and acceptable to the Engineer. C. All areas to be seeded shall be done by the hydraulic seeding method including all additives and amendments required. A "Reinco ", "Finn ", or "Bowie" type hydromulcher with adjustable nozzles and extension hoses, or equal, shall be utilized. General capacity of tank should range from 500 to 2,500 gallons, or as approved by the Engineer. D. Hydraulic seeding shall be carried out in three steps. Step one shall consist of the application of lime. In step two the seed mixture shall be mixed with the fertilizer, wood cellulose fiber mulch, and any required inoculants and applied to the seed bed. Step three shall consist of application of top dressing during the first spring or fall, whichever comes first, after step two. tor 31037102910.DOC:12 -15 -04 02910.DOC -5 INFLUENT SCREEN BUILDING ,.. RWSA E. Top dressing shall consist of a commercial grade fertilizer plus Nitrogen or other analysis as may be recommended by soil testing. Types and application rates of seed mixtures, lime, fertilizer, and wood cellulose fiber mulch, shall be as shown in the Seeding Schedule. F. Ingredients for the mixture and steps should be dumped into a tank of water and thoroughly mixed to a homogeneous slurry and sprayed out under a minimum of 300 -350 pounds pressure, in suitable proportions to accommodate the type and capacity of the hydraulic machine to be used. Applications shall be evenly sprayed over the ground surface. The Contractor shall free the topsoil of stones, roots, rubbish, and other deleterious materials and dispose of same off the site. The bare soil, except existing steep embankment area, shall be rough raked to remove stones, roots, and rubbish over 4- inches in size, and other deleterious materials and dispose of same off the site. G. No seeding should be undertaken in windy or unfavorable weather, when the ground is too wet to rake easily, when it is in a frozen condition, or too dry. Any bare spots shown in two to .,, three weeks shall be recultivated, fertilized at half the rate, raked, seeded, and mulched again by mechanical or hand broadcast method acceptable to the Engineer. H. Areas that have been seeded with a temporary seed mixture shall be mowed to a height of less than 2- inches and scarified prior to seeding with the permanent seed mixture. I. The Contractor shall provide, at his own expense, protection for all seeded areas against trespassing and damage at all times until acceptance of the work. Slopes shall be protected from damage due to erosion, settlement, and other causes and shall be repaired promptly at the Contractor's expense. Jos J. The Contractor shall water newly seeded areas of the lawn and road shoulder mix once a week until the grasses have germinated sufficiently to produce a healthy turf, or unless otherwise directed by the Engineer. Each watering shall provide three (3) gallons per square yard. The Contractor shall furnish all necessary hoses, sprinklers, and connections. K. The first and second cutting of the lawn grasses only shall be done by the Contractor. All subsequent cuttings will be done by the Owner's forces in a manner specified by the Contractor. 3.05 DITCH AND SWALE EROSION PROTECTION A. All ditches and swales indicated on the Drawings shall be lined with an erosion control blanket of single width. The area to be covered shall be properly graded and hydroseeded before the blanket is applied. Installation shall be in accordance with Section 02276, Erosion and Sedimentation Control. IMO 3.06 MAINTENANCE .,, A. The Contractor shall be responsible for maintaining all seeded areas through the end of his warranty period. Maintenance shall include but not be limited to, annual fertilization, mowing, repair of seeded areas, irrigation, and weed control. The Contractor shall provide, at his own expense, protection for all seeded areas against trespassing and damage at all times until acceptance of the work. Slopes shall be protected from damage due to erosion, settlement, and other causes and shall be repaired promptly at the Contractor's expense. 31037102910.DOC:12 -15 -04 02910.DOC -6 INFLUENT SCREEN BUILDING „�„ RWSA B. Annual fertilization shall consist of an application of 500 # /acre of 10 -10 -10 commercial grade fertilizer, or its equivalent and 60# /acre of nitrogen in early fall, or other analysis as may be wol determined by soil test. Annual fertilization shall be in addition to top dressing and shall be performed by the Contractor each fall season after planting until the work is substantially complete. C. Mowing shall be scheduled so as to maintain a minimum stand height of 4- inches or as directed by the Engineer. Stand height shall be allowed to reach 8 to 10- inches prior to mowing. D. All seeded areas shall be inspected on a regular basis and any necessary repairs or reseedings made within the planting season, if possible. If the stand should be over 60% damaged, it shall be re- established following the original seeding recommendations. E. Weed growth shall be maintained mechanically and /or with herbicides. When chemicals are . used, the Contractor shall follow the current Virginia Agricultural Experiment Stations' weed control recommendations and adhere strictly to the instructions on the label of the herbicide. No herbicide shall be used without prior approval of the Engineer. 3.07 CLEANUP A. The Contractor shall remove from the site all subsoil excavated from his work and all other debris including, but not limited to, branches, paper, and rubbish in all landscape areas, and remove temporary barricades as the work proceeds. B. All areas shall be kept in a neat, orderly condition at all times. Prior to final acceptance, the Contractor shall clean up the entire landscaped area to the satisfaction of the Engineer. �• 3.08 SEEDING SCHEDULE A. All seeding and mulching to be completed by the Contractor shall conform to the following schedule. No permanent seeding shall be performed from May 1 - August 31 and November 1 — February 14. Temporary seed mixtures will be used during these times if seeding is necessary. Areas seeded with temporary seed mixtures shall be reseeded by the Contractor at no additional cost to the Owner with permanent seed as directed by the Engineer. B. Application rates of seed mixtures, lime, fertilizer, mulch and top dressing are shown in the schedule. 31037102910.DOC:12 -15 -04 02910.DOC -7 INFLUENT SCREEN BUILDING Iwo RW SA d ƒ 6 3« NMI 0 0 o 0 \ -0 & / / \ 0 \ \ ( -1 IZ limi CL 2 m £ r § / 2 a) _ _ _ _ / 3 \\ 7 7 . ƒ e \ 2 ,%/ E E § R 2 W Ma E o D / \ k ƒ E o 2 m m m m 0) 0 0 E/ I E E E e » 0 @ o = © 0 a o 0 = 0 - \ / SM / - H \ F- \ }- \ = 0_ L ? ƒ _ $ -C $ = I % / 0 -J \ % \ 0 I.L. 2= c c c o 0 vii. -o 2 \ \ \ \ \ ƒ \ \ — £/ % a $ co $ a $ s 5 k � ± $ 0 m� > J > J ># « e a. / / / c 0 0 @ s CV 6 _ 0 g E - To 2 0 f 0 o iZ =2� / o \ OM [ e m § , , , / CC <ƒ I @ ° a) \ / f D 2 ow \ \ E o W 0 [ \ \ k um \ / / , , , \ Q m = o \ \ _Y CO / 0 0 0 Z $ H / ƒ U A. \ X 0 0 0 / \ 0 Q R ± ©�� = a m o N O \ 0 0 0 0 \ 0 0 2 7 2 0 0 0 0 0 = 7 0 0 nil 7 5 t t # = - 4-= § \ o o o tow \ 0 0 0 0 C / 9 3 0 0 o _o 2 e ƒ CO o m 2 0 \ CZ m # G CO . / eft 1:3 CV 0 o_ _ 0 / 0 0 0 0 E / \ E 0 0 0 0 = m 0 S G a a t b a » _ LT ° ¥ » / o 0 - / 2 a a) < n co =_ \ \ & % _ _ 3 : m o 2 _ \ \ < \ \ < \$ \ • / U 0 n ƒ 0 = 6 5 0 ° — 0 ° 2 o = Q E m 2 0 a » o a c .g e _ — u, 6 / \ / ƒ k \ . 0 3 / > 0) taw y ) o 0 G § \ Q. > / / < R CO . 2 E 4 m \ CD _ ƒ 3 @ G F- ± a 3 6 3 a. < 2 Appendix III Sub - surface Investigation rr SinCE r R SUBSURFACE EXPLORATION Moore's Creek WWTP Improvements Albemarle County, Virginia Prepared for Hazen and Sawyer, P.C. 4011 WestChase Boulevard Raleigh, North Carolina 26707 imp Made by Froehling & Robertson, Inc. 6181 Rockfish Gap Turnpike Crozet, VA 22932 war ism F &R Record No.: F71 -039G June 16, 2004 w. SINCE ■r FROEHLING & ROBERTSON, INC. GEOTECHNICAL • ENVIRONMENTAL • MATERIALS .. FROEHLING • LABORATORIES "OVER ONE HUNDRED YEARS OF SERVICE" 6181 Rockfish Gap Turnpike, Crozet, Virginia 22932 ISM 88 Telephone: (434) 823 -5154 • Fax: (434) 823 -4764 .11. RECORD NO. F71 -039G June 16, 2004 Hazen and Sawyer, P.C. era 4011 WestChase Boulevard Raleigh, North Carolina 26707 Attention: Mr. Christopher T. Phillips, P.E. Subject: Moore's Creek WWTP Improvements Albemarle County, Virginia Mr. Phillips: Froehling & Robertson, Inc. (F &R) has completed the authorized subsurface exploration and VOL geotechnical engineering evaluation for the above - referenced project. This work was performed in general accordance with our Proposal No. 0571 -008G dated May 5, 2004. Our report describes the exploration methods employed, provides pertinent data obtained and presents our recommendations for the proposed building construction. We appreciate the opportunity to be of service to you on this project. If you have any questions regarding the content of this report, please contact the undersigned. Sincerely, FROEHLI : t ! BERTSON, INC. # O / • CLYDE A. SIMMONS, III �r .. .0 37906 4 ods �/ 6 /oy G` -v" Ok { ONAL - Clyde A. , '.E. John L. Pappas, P.E. Geotechnical Engineer Senior Geotechnical Engineer vie Distribution: Addressee (1 original /3 copies) F \Projects F71 \F71 -039 (Moore's Creek WWTP)',Geo \Report doc maw HEADQUARTERS: 3015 DUMBARTON ROAD • BOX 27524 • RICHMOND. VA 23261 -7524 TELEPHONE (804) 264 -2701 • FAX (804) 264-1202 • www FandR tom BRANCHES: ASHEVILLE, NC • BALTIMORE, MD • CHARLOTTE, NC • CHESAPEAKE, VA 4WY CROZET, VA • FAYETTEVILLE, NC • FREDERICKSBURG, VA • GREENVILLE, SC HICKORY, NC • RALEIGH. NC • ROANOKE, VA • STERLING, VA Moore's Creek WWTP Improvments „ << "' Albemarle County, Virginia June 16, 2004 & BBi TABLE OF CONTENTS 1 "" SECTION PAGE 1 INTRODUCTION 1 1.1 PROJECT INFORMATION 1 1.2 SCOPE OF SERVICES 1 2 SUBSURFACE EXPLORATION PROCEDURES 2 3 SITE AND SUBSURFACE CONDITIONS 3 3.1 SITE DESCRIPTION 3 3.2 REGIONAL GEOLOGY 3 .r. 3.3 SUBSURFACE CONDITIONS 4 3.3.1 General 4 3.3.2 Surficial Materials 4 3.3.3 Existing Fill Soils 5 3.3.4 Residual Soils 5 3.3.5 Subsurface Water 5 "" 3.4 LABORATORY TESTING 5 4 DESIGN RECOMMENDATIONS 5 4.1 GENERAL 5 4.2 FOUNDATION SUPPORT 6 4.3 ESTIMATED SETTLEMENT 6 4.4 LATERAL EARTH PRESSURES 6 4.5 SEISMIC DESIGN CRITERIA 8 i.a 4.6 SLOPE STABILITY 8 5 CONSTRUCTION CONSIDERATIONS 8 ,.. 5.1 SITE PREPARATION 8 5.2 FOUNDATION CONSTRLCTION 9 5.3 STRUCTURAL FILL PLACEMENT 9 5.4 GROUNDWATER CONTROL 10 6 CONSTRUCTION QUALITY CONTROL 11 7 LIMITATIONS 11 1 i Nloore's Creek WWII' Improvments Albemarle County, Virginia June 16, 2004 r8,1z i e e i ,,, APPENDIX I ASFE Information About Geotechnical Reports Site Location Plan, Drawing No. 1 APPENDIX II Classification of Soil for Engineering Purposes Key to Soil Classification Laboratory Test Results Boring Logs B -1 through B -3 Boring Location Plan, Drawing No. 2 OM iii Moore's Creek WWTP lmprovments Albemarle County, Virginia June 16, 2004 r&R 1 INTRODUCTION 1.1 Project Information Project information was provided in your letter dated April 29, 2004, which included the proposed loading, foundation bearing level, and the "Top Plan ", "Band Screens Section ", and grading plan drawings. The project site is located within the existing Moore's Creek WWTP INN along the southern side of Franklin Street in Albemarle County, Virginia. A Site Location Plan is provided (Drawing No. 1 in Appendix I) in the Appendix. •�• It is understood improvements to the Moore's Creek WWTP are to include construction of a new Band Screens structure with a footprint of approximately 48 feet by 70 feet, located east of Grit Removal Basins No. 1 and No. 2. The western portion of the proposed structure will tie into the ion existing structure and is planned to be supported by a mat foundation with a bearing pressure of 2,000 psf. The remainder of the structure will be supported by spread footings, with column loads less than 200 kips and wall loads less than 5 kips per lineal foot. The finished floor level `.' for the western portion of the structure is planned for El 363, and the floor level steps up approximately 7 feet east of the compactor. Below grade walls are anticipated for the lower portion of the Band Screens structure. A portion of the existing Comminutor structure is located below grade within the footprint of the proposed structure. Based on a review of the proposed topography shown on the grading plan record drawing dated December, 1985 (and assuming that proposed grades shown thereon are currently the existing grades), cuts of up to 10 feet will be required to reach the anticipated subgrade levels. ... 1.2 Scope of Services The purposes of our involvement with this project were to (1) provide general descriptions of the subsurface soil conditions at the site, (2) perform geotechnical engineering analyses resulting in foundation design recommendations, and (3) comment on geotechnical aspects of the proposed development. In order to accomplish the above objectives, we undertook the following scope of services: 1. Visited the site to observe existing surface conditions and features and stake borings. 2. Coordinated utility clearance with Miss Utility officials and facilities personnel at the plant. 3. Reviewed and summarized readily available geologic and subsurface inforration relative to the project site. 4. Executed a subsurface exploration consisting of three borings. 5. Performed laboratory testing on representative soil samples recovered from the site in order to confine visual soil classifications and estimate pertinent engineering properties of the soils. 1 N1oore's Creek WWTP Improvments I• Albemarle County, Virginla June 16, 2004 6. Evaluated the subsurface information relative to geotechnical design issues for the �► new Band Screen structure with estimate of allowable bearing pressures, settlement, lateral pressures for below -grade walls walls, and modulus of subgrade reaction for slab design. 7. Prepared this written report summarizing our work on the project, providing descriptions of the subsurface conditions encountered, providing foundation and design criteria and discussing geotechnical related aspects of the proposed construction. Copies of Test Boring Logs and laboratory tests performed are included. 2 SUBSURFACE EXPLORATION PROCEDURES The subsurface exploration program consisted of three borings, designated as B -1 through B -3. The exploration program was perfomred on May 19, 2004 at the approximate locations presented '" on the Boring Location Plan (Drawing No. 2, Appendix II). The boring locations were staked in the field by F &R representatives by taping from existing site features. Minor adjustments to the boring locations were made as necessary due to underground utility conflicts. Boring elevations were interpolated to the nearest + / -one foot from the proposed topography depicted on the provided grading plan drawing. The boring locations and elevations shown on the attached Boring Logs should not be inferred to be more accurate than the methods used in their oft determination. The test borings were performed in general accordance with generally accepted practice using a truck- mounted rotary drill rig. Hollow stem augers were advanced to pre - selected depths, the center plug was removed and disturbed soil samples were recovered with a standard split -spoon ■. sampler (2 -1/4 inch I.D.) in general accordance with ASTM D 1586, the Standard Penetration Test. In this test, a weight of 140 pounds is dropped from a height of 30 inches to drive the spilt soil sampler into the soil. The number of blows required to drive the split -spoon sampler three om (3) consecutive 6 -inch increments is recorded and the blows of the last two (2) increments are added to obtain the Standard Penetration Resistance (N- value) in blows per foot (bpf). The N- value is a measure of in -situ soil conditions and has been correlated with certain engineering properties of soils. In some soils it is not always practical to drive a split -spoon sampler three (3) consecutive 6 -inch increments. Whenever more than 50 blows are required to drive the sampler over a 6 -inch increment, the condition is called split -spoon refusal. Split -spoon refusal conditions may occur because of obstructions or because the earth materials being tested are very dense or very hard. When split -spoon refusal occurs, often little or no sample is recovered. The SPT N -value for split spoon refusal conditions is typically estimated as >100 blows per foot (bpf). Where the sampler is observed not to penetrate after 10 blows, the N -value is reported as 10/0. Otherwise, the depth of penetration after 50 blows is reported in inches (i.e. 50/5, 50/3, etc.). opo Moore's Creek \'WTP Irnprovments Albemarle County, Virginia June 16. 2004 F°81Z 88 Auger refusal is a designation applied to any material that cannot be penetrated by the soil auger and is normally indicative of a very hard or very dense material, such as boulders, rock lenses or the `" upper surface of bedrock. Auger refusal discussed herein is based on conditions impenetrable to our drilling equipment (CME 55). Auger refusal conditions with a CME 55 do not necessarily indicate conditions impenetrable to other equipment. Auger refusal conditions may exist intermediate of the boring locations or in unexplored areas of the site. The test borings were advanced through the soil overburden into the underlying materials by soil drilling procedures to the planned termination depths or auger refusal, whichever occurred first. Cave -in depth and subsurface water level readings were taken in each of the borings upon completion of the drilling process. The boreholes were backfrlled with auger cuttings (soil) prior to our demobilization from the site. Periodic observation of the boreholes should be performed to monitor subsidence at the ground surface, as the borehole backfill could settle over time. Representative portions of the split spoon soil samples obtained throughout the exploration program were placed in glass jars upon recovery and transported to our laboratory. In the 41111" laboratory, the soil samples were evaluated by a member of our engineering staff in general accordance with techniques outlined in the visual- manner identification procedures (ASTM D 2488) and the Unified Soil Classification System. The soil classifications are discussed in this report. The soil descriptions and classifications discussed in this report and shown on the attached Boring Logs are based on visual observation and should be considered approximate. Classification procedures used for this exploration are further explained in Appendix II. Split -spoon soil samples recovered on this project will be stored at F &R's laboratory for a period of ,.. sixty days. After sixty days, the samples will be discarded unless prior notification is provided to us in writing. 1101 3 SITE AND SUBSURFACE CONDITIONS 3.1 Site Description oft The new structure is planned east of the existing grit removal basins and north of the parking lot for the Administration and Control Building in an area which is currently relatively level and grass- covered. The site area is located near the crest of a slope at approximately El 373, which slopes down to the north to the existing driveway at El 365. As previously indicated, a portion of the comminutors structure is located underground in the area of the proposed structure. A concrete sidewalk runs through the site in the north -south direction. Additionally, numerous underground utilities are known to be located within the footprint of the proposed structure. It is anticipated that some of these existing utilizes will be rerouted, while others will be left in place. 3.2 Regional Geology The project site is located in an upland area of the Piedmont Plateau, at the western edge of the Piedmont Physiographic Province, an area underlain by ancient metamorphic rocks. Information obtained from publication entitled Geology and ;Mineral Resources of Albemarle Counties r. Moore's Creek WWTP Improvments „ r Albemarle County, Virginia June 16, 2004 r&R (Virginia Division of Mineral Resources Bulletin No 77, 1962) indicates that this area is underlain by the Catoctin Formation, of the Precambrian or Cambrian Age. The Catoctin 4 p , Formation is described as originally a series of basaltic lava flows separated by layers of sediments, now a greenstone with patches of epidote. The virgin soils encountered in this area are the residual product of in -place chemical and mechanical weathering of the parent bedrock formation that underlies the site. These materials consist of clayey soils near the surface where soil weathering is more advanced, underlain by sandy SILTS and silty SANDS. The boundary between soil and rock is often times not sharply defined. The transitional term "Hard or Soft Weathered Rock" is normally found overlying the parent bedrock. For engineering purposes, SWR is described as broken and partially weathered rock with Standard Penetration Resistance w•. N- values between 50 blows per 6 inches and 50 blows per inch. HWR is described as broken and partially weathered rock with N values in excess of 50 blows per inch. J + Weathering is facilitated by fractures, joints and the presence of Less resistant rock types. Consequently, the profile of the SWR or HWR is often quite irregular, even over very short horizontal distances. Also, it is not unusual to find lenses, layers, or zones of less resistant SWR Vit and more resistant HWR, and boulders of hard rock and within the soil mantle well above the general bedrock level. 3.3 Subsurface Conditions 3.3.1 General Data from the specific soil test borings are shown on the attached Boring Logs in Appendix II. The subsurface conditions discussed in the following paragraphs and those shown on the Boring Logs represent an estimate of the subsurface conditions based on the interpretation of the boring data using normally accepted geotechnical engineering judgments. The transitions between different soil strata are usually less distinct than those shown on the Boring Logs. Although individual soil test borings are representative of the subsurface conditions at the boring locations on the dates shown, they are not necessarily indicative of subsurface conditions at other locations ""' or at other times. Below the existing ground surface, the soil test borings encountered surficial materials underlain by existing fill soils and residual soils. These materials are generally discussed in the following paragraphs. War 3.3.2 Surficial Materials Surficial soils typically contain root mat and /or other fibrous organic matter and are generally unsuitable for engineering purposes. Surficial soils were encountered at each of the boring locations to a depth of 4 inches. Actual depths will vary in unexplored areas of the site. 4 Moore's Creek WWII' Improvments Albemarle County, Virginia June 16, 2004 f tZ d a - 3.3.3 Existing Fill Soils Existing fill soils may include any materials deposited by man. Existing fill soils were encountered in borings B -1 and B -3 below the surficial soils and extended to a depth of 8.5 feet below existing grades. Sampled existing fill materials consisted of SILT (ML), elastic SILT (MH) and GRAVEL (GM). N- Values ranging from 3 bpf to 15 bpf were recorded in the fill soils, indicating that the fill materials were subjected to variable degrees of compaction effort. The fill materials are believed to consist of backfill placed during the construction of the underground utilities which run through the site. 3.3.4 Residual Soils Residual soils were encountered at each of the boring locations below the surficial materials in boring B -2 and below the existing fill soils in borings B -1 and B -3. The sampled residual soils consisted of SILT (ML), elastic SILT (MH), and silty SAND (SM). The residual soils were generally tan, brown, reddish brown, and reddish tan in color, with moisture contents visually "+w' characterized as moist to very moist. SPT N- values ranged from 5 bpf to 63 bpf. 3.3.5 Subsurface Water The test borings were monitored to obtain groundwater information during drilling operations at the project site and upon completion after removal of the augers. Groundwater was not encountered during drilling operations or upon removal of the augers in any of the borings. It should be noted that fluctuations in subsurface water levels and soil moisture can be anticipated with changes in precipitation, run -off, and seasonal /climatic conditions. 3.4 LABORATORY TESTING Laboratory tests were performed on selected split -spoon samples in general accordance with ASTM standards. The tests performed were moisture content (ASTM D 2216), Atterberg Limits (ASTM D 4318), gradation analyses (ASTM C 136), and Standard proctor (ASTM D 698). The moisture contents ranged from 14.5% to 55.7 %, and are indicated on the boring logs. The laboratory test results can be found in the Appendix. 4 DESIGN RECOMMENDATIONS 4.1 General The following evaluations and recommendations are based on our observations at the project site, interpretation of the field data obtained during this subsurface exploration and our experience with similar subsurface conditions and projects. Soil penetration data has been used to estimate an allowable bearing pressure using established correlations. Subsurface conditions in unexplored locations may vary from those encountered in our exploration. 5 Moore's Creek WW FP Improvrnents SIMLI "O Albemarle County, Virginia June 16, 2004 r&R ae Determination of an appropriate foundation system for a given structure is dependant on the proposed structural loads, soil conditions and construction constraints such as proximity to other structures. The subsurface exploration aids the geoteclmical engineer in determining the soil stratum appropriate for structural support This deteuiiination includes considerations with regard to both allowable bearing pressure and compressibility of the soil strata. In addition, since the method of construction greatly affects the soils intended for structural support, consideration must be given to the implementation of suitable methods of site preparation, sequences used for Vat excavation, underpinning, shoring, and the compaction of areas to receive structural fill. 4.2 Foundation Support The test borings indicated variable foundation subgrade materials, consisting of existing fill ._4 materials and residual soils. These materials were relatively variable with respect to consistency /density and moisture contents. Considering the potential for excessive differential settlements as a result of the variable founding conditions, F &R recommends that the entire (61`' structure be supported on a mat foundation, rather than mixing mat foundations with spread footings and continuous footings. We recommend that the mat foundation be designed for a maximum bearing pressure not to exceed 2,000 pounds per square foot (psf). If the mat foundation is designed using the flexible method, a modulus of subgrade reaction, k is necessary. Based on the proposed loading and the anticipated soil conditions, a k of 25 pci should be utilized. 4.3 Estimated Settlement Based on the boring data and anticipated bearing structural load information, we anticipate total settlements for the proposed structure will less than ''A inch with differential settlement of up to one -half the estimated total settlement. The magnitude of differential settlements will be influenced by the variation in excavation requirements across the building footprint, the distribution of loads, and the variability of underlying soils. n'"' Our settlement analysis was performed on the basis of structural and excavation assumptions discussed in the project information section of this report. Actual settlements experienced by the structure and the time required for these soils to settle will be influenced by undetected variations in subsurface condition, actual structural loads, final grading plans, and the quality of fill placement and foundation construction. 4.4 Lateral Earth Pressures The following information is provided to aid in analysis of soil loads on below -grade walls. Earth pressures on walls below grade are influenced by structural design of the walls, conditions of wall restraint, methods of construction and /or compaction, and the strength of the materials being •. restrained. The most common conditions assumed for earth retaining wall design are the active and at -rest conditions. Active conditions apply to relatively flexible earth retention structures, such as • freestanding walls, where some movement and rotation may occur to mobilize soil shear strength. 6 Moore's Creek WWTP Impro‘ments Albemarle County, Virginia June 16, 2004 r&R i B P M1 Walls that are rigidly restrained, such as basement, pit, pool and tunnel walls, should be designed for the structure requiring the use of at -rest earth pressures. A third condition, the passive state, represents the maximum possible pressure when a structure is pushed against the sod, and is used in wall foundation design to help resist active or at -rest pressures. Because significant wall movements are required to develop the passive pressure, the total calculated passive pressure should be reduced by one -half to two- thirds for design purposes. We recommend that Sandy SILT (ML) soils, with a maximum of 70 percent passing the No. 200 Sieve by weight, or more granular be utilized as wall backfill. We do not recommend the use of w elastic silt (MH) or fat clay (CH) soils for wall backfill. As an alternative to using the on -site SILT (ML) or more granular soils, VDOT No. 57 Stone may be utilized as backfill behind below grade walls. The lateral earth pressure parameters for SILT (ML) or more granular soils are included in the table below. These values are based on previous experience with similar soils and construction, and empirical correlations. Soil Type Base Friction Lateral Earth Equivalent Fluid Coefficient Pressure Unit Weight (y pcf) Coefficient (k) At -rest Active At -rest Active Passive SILT (ML) or more 0.30 0.53 0.36 64 44 250 granular _ VDOT No. 57 0.30 0.36 0.22 38 23 250 Stone A moist soil unit weight of 120 pcf and 105 pcf should be used for design calculations for SILT (ML) and VDOT No. 57 Stone, respectively. The backfill material should be extended a minimum distance of 0.5 times the wall height laterally from the back face of the wall, or for a cantilevered wall, from the heel of the wall footing. *IV Our recommendations assume that the ground surface above the walls is level. The recommended equivalent fluid pressures are only applicable if the backfill used for the wall system is free draining or a constantly functioning drainage system is installed between walls and soil backfill to prevent the accidental buildup of hydrostatic pressures and lateral stresses in excess of those stated. If a functioning drainage system is not installed, then lateral earth pressures should be determined using the buoyant weight of the soil. Hydrostatic pressures calculated with the unit weight of water (62.4 pcf) should be added to these earth pressures to obtain the total stresses for design. A filter fabric wrapped VDOT No. 57 crushed stone drainage blanket or a manufactured drainage board should be utilized to provide drainage behind walls. Adequate outlets to discharge any free water must also be provided. This may be accomplished by a perforated PVC pipe (4 -inch minimum diameter, rigid or flexible) located behind the wall, which will collect free water and discharge it to daylight or into the stormwater collection system. Use of a drainage medium does 7 ``loore's Creek 1vw{P Impro\ments '% ; \lbemarle County, Virginia June 16, 2004 r8,R not reduce the lateral earth pressures, but only serves to prevent the development of hydrostatic pressures on the wall. Heavy equipment should not operate within 5 feet of below grade walls to prevent lateral pressures in excess of those cited. Adjacent footings or other surcharge loads located a short distance outside below grade walls will also exert appreciable additional lateral pressures. Surcharge loads should be evaluated using the appropriate active or at -rest pressure coefficients provided above. The effect of surcharge loads should be added to the recommended earth PIM pressures to determine total lateral stresses. """ 4.5 Seismic Design Criteria Based on the subsurface data obtained, our experience with general geologic conditions in the vicinity, and the soil profile type descriptions as set forth in the 2000 International Building Code, Table 1615.1.1, we recommend using a site classification of D for a soil profile described we as stiff soil with average N- values between 15 bpf and 50 bpf. 4.6 Slope Stability Our scope of work did not include a detailed analysis of slope stability, however, we offer the following general guidelines. For a maximum height of 20 feet, we recommend temporary slopes wit no steeper than 1.5(H):1.0(V) and permanent slopes no steeper than 2.0(H):1.0(V) for construction in undisturbed residual soils or newly compacted structural fill placed in accordance with our IOW recommendations. The slope recommendations are appropriate for slopes underlain by competent materials. In building and pavement areas, minimum top of slope setbacks of 10 feet and 5 feet are recommended, respectively. awk During construction, temporary slopes should be regularly evaluated for signs of movement or unsafe conditions. Soil slopes should be covered for protection from rain, and surface runoff should be diverted away from the slopes. For erosion protection, a protective cover of grass or other vegetation should be established on permanent soil slopes as soon as possible. These general slope recommendations are appropriate for slopes underlain by competent materials. However, the provided recommendations should not be used to deviate from OSHA regulations. Construction should be performed in accordance with applicable OSHA regulations. 5 CONSTRUCTION CONSIDERATIONS NIL 5.1 Site Preparation r ., Before proceeding with construction, any surficial organic soils, pavements, existing utilities, and other deleterious non -soil materials should be stripped or removed from the proposed construction area. Underground utilities should be re- routed to locations a minimum of 10 feet +�* outside of the proposed structures. 8 ism Moore's Creek WWTP Improvments r* Albemarle County, Virginia June 16, 2004 r&R � ,A6 After clearing and stripping a required minimum of 5 feet outside the areas intended to support '�►' floor slabs, pavements, new fill, and foundations and after excavation to subgrade levels we recommend observation by an engineer from our office and proofrolling the surface of the soil to identify soft spots. The proofrolling should be performed using a fully loaded tandem axle dump truck with a minimum weight of 20 to 30 tons or other pneumatic -tired vehicle of similar size and weight. Proofrolling should be performed in the presence of the geotechnical engineer. Any areas which are seen to pump, wave, or rut, and do not stabilize after several passes of a compactor, should be evaluated by the geotechnical engineer for remedial actions. Proofrolling should not be attempted in wet weather as proofrolling in wet weather may cause deterioration of these soils and result in additional undercuts that may not otherwise be necessary. Also, subgrade soils which are frozen or severely desiccated should be stripped prior to proofrolling. Additionally, construction traffic should not be allowed to concentrate in future pavement or 01 structural areas as this could deteriorate the moisture sensitive soils. 5.2 Foundation Construction All foundation subgrades should be observed, evaluated, and verified for the design bearing pressure by the geotechnical engineer after excavation and prior to reinforcement steel placement. If loose /soft soils are encountered during foundation construction, localized undercutting and/or in- place stabilization of foundation subgrades will be required. The actual need for, and extent of, undercutting should be based on field observations made by the geotechnical engineer at the time of construction. Excavations for footings should be made in such a way as to provide bearing surfaces that are firm and free of loose, soft, wet, or otherwise disturbed soils. Foundation concrete should not be placed on frozen or saturated subgrades. If such materials are allowed to remain below foundations, settlements will increase. Foundation excavations should be concreted as soon as practical after they are excavated. If an excavation is Left open for an extended period, a thin mat of lean concrete should be placed over the bottom to minimize damage to the bearing surface from weather or construction activities. Water should not be allowed to pond in any excavation. m ,„ 5.3 Structural Fill Placement Earthwork for this project is anticipated to consist of excavation to the subgrade levels for the Band Screens structure, backfilling the below grade walls, and backfilling for any underground utility installations associated with this project. The on site materials may be used as controlled structural fill, provided placement is monitored by a soils technician and tested during the backfill and compaction activities. In addition, backfill behind below grade walls should consist of SILT (ML) or more granular soils, with less than 70 percent passing the No. 200 Sieve. Any off site borrow soils should consist of silty SAND (SM) or more granular soils. Other materials may be suitable for use as controlled structural fill and should be individually evaluated by the geotechnical engineer. Controlled structural fill should be free of boulders, cobbles, organic 9 Moores Creek 1VWTP Improvments Albemarle County, Virginia June 16, 2004 r8,R matter, debris, or other deleterious materials. All fill soils should have a maximum particle size no greater than 4 inches. In addition, we recommend a minimum Standard Proctor (ASTM D 698) maximum dry density of 90 pounds per cubic foot (pcf) for stnictural fill materials. Excessively wet or dry soils should not be used as fill materials without proper drying or wetting. In general, we recommended a moisture content range of plus or minus 2 percent of the material's optimum moisture content. We recommend that the contractor have equipment on site ••• during earthwork for both drying and wetting of fill soils. We do not anticipate significant problems controlling moistures within the fill during periods of dry weather, but moisture control may be difficult during winter months or extended periods of rain. Attempts to work the soils when wet can be expected to result in deterioration of otherwise suitable soil conditions or of previously placed and properly compacted fill. Where construction traffic or weather has disturbed the subgrade, the upper 8 inches of soils intended for structural support should be CIS scarified and re- compacted. The laboratory test results indicate that the moisture contents of several samples were well above aft the anticipated optimum moisture contents (i.e. 6 of the 8 samples tested had moisture contents above 32 percent by weight). The fine grained soils, particularly the elastic SILT (MH) soils will o ,,, be extremely difficult to work with at their current moisture content. Considering the relatively limited amount of backfilling to be done for this project, and the limited working area available to dry back wet soils, it may be more efficient to utilize granular off site borrow for backfilling. Fill materials should be placed in horizontal lifts with a maximum compacted lift thickness of 8 inches. The fill should be compacted to a minimum of 95 percent of the material's maximum dry i "' density as determined by the standard Proctor method (ASTM D 698). We anticipate that narrow utility trenches will require portable compaction equipment and thin lifts of 3 to 4 inches to achieve specified degrees of compaction. In grassed non - structural areas the compaction requirements may be reduced to a minimum of 90 percent of the material's maximum dry density as determined by the standard Proctor method. Each lift of the fill should be tested in order to confirm that the recommended degree of compaction is attained. Field density tests to determine 011 compaction should be performed for every 2500 square feet, with a minimum of three tests per lift. In utility trenches or behind walls, field density testing should be performed every 50 lineal feet, with a minimum of two tests between structures. Any areas that do not meet the compaction specifications should be moisture- adjusted and/or recompacted to achieve compliance. 5.4 Groundwater Control •r. Based on the boring data, we do not anticipate groundwater will be encountered during anticipated excavation for the proposed structures. Groundwater levels are subject to seasonal, climatic, and other variations and may be different at other times and locations than those stated in this report. Any ground water encountered would most likely be a result of surface water infiltration and perched water conditions, and should be readily managed by interceptor trenches es and localized systems of sumps and pumps. 10 Moores Creek rP Improvments Albemarle County, Virginia June 16, 2004 F.8,R 6 CONSTRUCTION QUALITY CONTROL F &R recommends that we be given the opportunity to review the foundation plan, grading plan and project specifications when design documents approach completion. This review evaluates whether the recommendations and comments provided herein have been understood and properly implemented. We also recommend that F &R be retained for professional and construction materials testing (CMT) services during construction on this project. Our continued involvement on this project helps provide continuity for proper implementation of the recommendations discussed herein. These services are not part of our currently authorized scope of work. 7 LIMITATIONS This report has been prepared for the exclusive use of Hazen and Sawyer, P.C., or their agent, for the specific application to the Moore's Creek WWTP Improvements project located in Albemarle County, Virginia, in accordance with generally accepted soil and foundation engineering "` practices. No other warranty, express or implied, is made. Our recommendations are based on the limited design information fumished to Froehling & Robertson, Inc., the data obtained during the subsurface exploration program, and generally accepted geotechnical engineering practice. usi The conclusions and recommendations do not reflect variations in subsurface conditions, which could exist intermediate of the boring locations or in unexplored areas of the site. Regardless of the thoroughness of a subsurface exploration, there is the possibility that conditions between borings will differ from those at the boring locations, that the conditions are ,. not as anticipated by the designers, or that the construction process has altered the soil conditions. Therefore, experienced geotechnical engineers should evaluate earthwork, pavement and foundation construction to verify that the conditions anticipated in the design actually exist. Otherwise, we assume no responsibility for construction compliance with design concepts, specifications or recommendations. In the event that changes are made in the design or location of the proposed structure, the recommendations presented in the report shall not be considered valid unless the changes are reviewed by our firm and recommendations of this report modified and/or verified in writing. If ins this report is copied or transmitted to a third party, it must be copied or transmitted in its entirety, including text, attachments and enclosures. Interpretations based on only a part of this report may not be valid. This report contains 11 pages of text and the attached appendices. NMI Mlle NMI 11 r.. - IMPORTANT INFORMATION ABOUT YOUR GEOTECHNICAL ENGINEERING REPORT - iow As the client of a consulting geotechnical engineer, you MOST GEOTECHNICAL FINDINGS ARE should know that site subsurface conditions cause more PROFESSIONAL JUDGMENTS a u construction problems than any other factor ASFE/The Site exploration identifies actual subsurface conditions Association of Engineering Firms Practicing in the only at those points where samples are taken The data Geosciences offers the following suggestions and were extrapolated by your geotechnical engineer who observations to help you manage your risks then applied judgment to render an opinion about sis overall subsurface conditions The actual interface A GEOTECHNICAL ENGINEERING REPORT IS BASED between materials may be far more gradual or abrupt ON A UNIQUE SET OF PROJECT - SPECIFIC FACTORS than your report indicates Actual conditions in areas no Your geotechnical engineering report is based on a not sampled may differ from those predicted ih your subsurface exploration plan designed to consider a report While nothing can be done to prevent such unique set of project- specific factors These factors situations, you and your geotechnical engineer can work typically include the general nature of the structure together to help minimize their impact Retaining your ow involved, its size, and configuration, the location of the geotechnical engineer to observe construction can be structure on the site, other improvements, such as particularly beneficial in this respect access roads, parking lots, and underground utilities, A REPORT'S RECOMMENDATIONS al . and the additional risk created by scope -of- service limitations imposed by the client To help avoid costly CAN ONLY BE PRELIMINARY problems. ask your geotechnical engineer to evaluate The construction recommendations included in your how factors that change subsequent to the date of the geotechnical engineer's report are preliminary. because ON report may affect the report's recommendations they must be based on the assumption that conditions revealed through selective exploratory sampling are Unless your geotechnical engineer indicates otherwise, indicative of actual conditions throughout a site do not use your geotechnical engineering report Because actual subsurface conditions can be discerned iro only during earthwork. you should retain your geo- • when the nature of the proposed structure is technical engineer to observe actual conditions and to changed, for example, if an office building will he finalize recommendations Only the geotechnical so• erected instead of a parking garage, or a refrigerated engineer who prepared the report is fully familiar with warehouse will be built instead of an unrefngerated the background information needed to determine one, whether or not the report's recommendations are valid • when the size. elevation, or configuration of the and whether or not the contractor is abiding by appli- o.s proposed structure is altered, cable recommendations The geotechnical engineer who • when the location or orientation of the proposed developed your report cannot assume responsibility or structure is modified, liability for the adequacy of the report's recommenda- • when there is a change of ownership, or tions if another party is retained to observe construction ow • for application to an adjacent site. GEOTECHNICAL SERVICES ARE PERFORMED Geotechnical engineers cannot accept responsibility for FOR SPECIFIC PURPOSES AND PERSONS ow problems that may occur if they are not consulted after Consulting geotechnical engineers prepare reports to factors considered in their report's development have meet the specific needs of specific individuals A report changed prepared for a civil engineer may not be adequate for a construction contractor or even another civil engineer ... SUBSURFACE CONDITIONS CAN CHANGE Unless indicated otherwise, your geotechnical engineer A geotechnical engineering report is based on condi- prepared your report expressly for you and expressly for Lions that existed at the time of subsurface exploration purposes you indicated No one other than you should Do not base construction decisions on a geotechnical apply this report for its intended purpose without first r engineering report whose adequacy may have been conferring with the geotechnical engineer No party affected by time Speak with your geotechnical consult- should apply this report for any purpose other than that ant to learn if additional tests are advisable before originally contemplated without first conferring with the .ni construction starts Note, too, that additional tests may geotechnical engineer be required when subsurface conditions are affected by GEOENVIRONMENTAL CONCERNS construction operations at or adjacent to the site, or by natural events such as floods. earthquakes, or ground ARE NOT AT ISSUE i'"' water fluctuations Keep your geotechnical consultant Your geotechnical engineering report is not likely to apprised of any such events relate any findings. conclusions or recommendations MIN about the potential for hazardous materials existing at mates was not one of the specific purposes for which it the site The equipment, techniques, and personnel was prepared In other words, while a contractor may used to erform a geoenvironmental exploration differ p g p gain Important knowledge from a report prepared for substantially from those applied in geotechnical another party, the contractor would be well - advised to engineering Contamination can create major risks If discuss the report with your geotechnical engineer and you have no information about the potential for your to perform the additional or alternative work that the site being contaminated, you are advised to speak with contractor believes may be needed to obtain the data your geotechnical consultant for information relating to specifically appropriate for construction cost estimating geoenvironmental issues purposes ) Some clients believe that it is unwise or unnecessary to give contractors access to their geo- A GEOTECHNICAL ENGINEERING REPORT IS technical engineering reports because they hold the SUBJECT TO MISINTERPRETATION mistaken impression that simply disclaiming responsi- Costly problems can occur when other design proles- bility for the accuracy of subsurface information always sionals develop their plans based on misinterpretations insulates them from attendant liability Providing the of a geotechnical engineering report To help avoid best available information to contractors helps prevent misinterpretations, retain your geotechnical engineer to costly construction problems It also helps reduce the work with other project design professionals who are adversarial attitudes that can aggravate problems to affected by the geotechnical report Have your geotech- disproportionate scale. nical engineer explain report implications to design professionals affected by them, and then review those READ RESPONSIBILITY CLAUSES CLOSELY Imo design professionals' plans and specifications to see Because geotechnical engineering is based extensively how they have incorporated geotechnical factors on judgment and opinion, it is far less exact than other Although certain other design professionals may be fam- design disciplines This situation has resulted in wholly (liar with geotechnical concerns, none knows as much unwarranted claims being lodged against geotechnical about them as a competent geotechnical engineer engineers To help prevent this problem, geotechnical engineers have developed a number of clauses for use in BORING LOGS SHOULD NOT BE SEPARATED their contracts, reports, and other documents Responsi- �. FROM THE REPORT bility clauses are not exculpatory clauses designed to Ceotechnical engineers develop final boring logs based transfer geotechnical engineers' liabilities to other upon their interpretation of the field logs (assembled by parties Instead, they are definitive clauses that identify site personnel) and laboratory evaluation of field where geotechnical engineers' responsibilities begin and samples Geotechnical engineers customarily Include end Their use helps all parties involved recognize their only final boring logs in their reports Final boring logs individual responsibilities and take appropriate action should not under any circumstances be redrawn for Some of these definitive clauses are likely to appear in inclusion in architectural or other design drawings. your geotechnical engineering report Read them because drafters may commit errors or omissions in the closely Your geotechnical engineer will be pleased to transfer process Although photographic reproduction give full and frank answers to any questions eliminates this problem, it does nothing to minimize the +� possibility of contractors misinterpreting the logs during RELY ON THE GEOTECHNICAL ENGINEER bid preparation When this occurs, delays, disputes. and FOR ADDITIONAL ASSISTANCE unanticipated costs are the all- too - frequent result Most ASFE - member consulting geotechnical engineer - 1 ing firms are familiar with a variety of techniques and `r" To minimize the likelihood of boring log misinterpreta- approaches that can be used to help reduce risks for all non, give contractors ready access to the complete parties to a construction protect, from design through geotechnical engineering report prepared or authorized construction Speak with your geotechnical engineer not for their use (If access is provided only to the report only about geotechnical issues. but others as well. to prepared for you. you should advise contractors of the learn about approaches that may be of genuine benefit report's limitations, assuming that a contractor was not You may also wish to obtain certain ASFE publications. one of the specific persons for whom the report was Contact a member of ASFE of ASFE for a complimentary prepared and that developing construction cost esti- directory of ASFE publications ' rrr A S F FIRMS PRACTICING IN THE GEOSCIENCES 88H COLESVILLE ROAD /SUITE G106 /SILVER SPRING, MD 20910 TELEPHONE 301/565 -2733 FACSIMILE 301/589 -2017 rrrr C 1492 by ?SFE Inc Unless ASFE grants specik permrssien to do so duphcaticn of this document by any means whatsoever .s erp'easly prohrbned Re use of the .cording in Ihis document In whole or in part also I expressly prohibited and may he done only wub t express permission of AS RE or for purposes of revew or scholarly. research BPCO59:P135M rr — __� - - _- - -___� - - -- _— _ -- -- ---- — - - -- — — ____ __ _ -- NM 1 • 1 PF,�� �� i ..� I O P / � RANKUN \ RURfOG 1 �) 1s�f � > l , a RU, 8.1.= —� I ``P � ��, // f - ,., . a±' % / um Rea h ems— - � & t r / I ° .,. -' 'Z' R �. 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S o'nt ; Ito fG Visitors co -0^ - .. � /-; 0* & Arboretum i / /% % Ticket Office Shuttle hori o ; Iglu SINCE NO FROEHLING & ROBERTSON, INC. - DATE: June 16, 2004 r&R GEOTECHNICAL • ENVIRONMENTAL • MATERIALS SCALE: 1" - 2000' ENGINEERS • LABORATORIES tag EA. , "0VER ONE HUNDRED YEARS OFSERVICE'• DRAWN: repro F71 -039G Moore's Creek WWTP Improvements SITE DRAWING NO. LOCATION Albemarle County, Virginia PLAN I r8lz NMI BED APPENDIX II IMO wok INN s r N C r MIN r* 1 1 s . ila* CLASSIFICATION OF SOILS FOR ENGINEERING PURPOSES ASTM Designation: D 2487 SOIL ENGINEERING ur (Based on Unified Soil flostification System) I Sail Classification Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests" csymeol Group Name' II. COARSE -G AWED 5 Oil 5 Gravels Clean Grayed dux 4 and i sCcs]' (AN MA graded g rave( Mae hen 50% retained on No. 200 sieve Mon than 50% Less than 5% fines` Cu <4 arldra 1 >Co 0' GP Poorly graded grave mars* traction retaining on No. 4 sieve Gravels with Frees Fns classify as MIL or MH GM Silty gam`" Wee rs gun 12% fines' Fines classify as CL or C14 GC' Clayey gravel /N Sands Clean Sands Cu26 and 1 LCCS7' SW Weigaded sand 50% or more of roars. Lm tan 5% Mee traction passes No. 4 slave Carte ard'> 1 SP Poorly graded sand' fIM Sands with Foes. Fines c assdy *s Ml or MN SM 5i1y sand` Wee Own 12X Oros' Fars clossiy as CL or CH SC Clayey sand"" FINEGRAINED SOILS Salts and Clays Inorganic PP7 and plots on or Cl Lean day""' 50% or more passes the Na 200 saw' Liquid Lima tau than 50 above - A' Fir' Ida PI<-4 or plots be - A• fine' ML Sin"' O ya"c L th 0.75 OL Organic day''''' day''''' — ied lift Organic sae" S+7ts and Clays Inorganic P1 pas on or X. W ine CH Fat day''' Liquid irli 50 or mac PI pas below - A' Fne MH Baser sY"" 104 Organic Lipa:d east -oven died <0.75 OH Organic day'' r / Ontario si " ONO HIGHLY ORGANIC SOILS Primarily organic mailer, dart it cola, and organic odor PT Peat ''Based an be malarial passing the 9-it (75 nwni sieve Y Atleroeng Finds pint in hand sd area, soli is a CLAI silty day. 't i'.4 sampe contained cobbles Or bosid.n. or bor>, add 10J' '1 sail m4ains 15 b 29% plus Na. 200 add Vw4V1 aan1C 0' tir461 SOO lvih cct+bbs or boulders, or both" to group name. E Cu -0. f0.. Cc . 133-; gravel *turnover is predominant `Gravels wih 5 le 12% lees require del rymootx 'V sot contains L 30% plus No. 204 prWosenortty sand, add GW 4Ni - waded Travel with aR %adf to group ream.. GW-119 wail-graded gravel with fit' '1 sod contain a: 15% sand. add -wen sand' to 'Y ,oil contains z 30% psi I4o. 200 pneclominoNlY griVel add GP-GM poot traded travel with sat grail IS 'gravely 10 group name. law GPtG.p?o!lg_iraded grave wart crew '11 Anns classify ea CLAI.. use dual symbol GC- "PI 2 4 Ind pea on or above W ir. 'Sand� w 61d. 12% Ana raqui* dual symbols: GAL or SC IN o 4 a plots blow W e Ina. sy'A>,1 f tore graded sand wah lit "14 lees ah organic. add 'With organic gnus" 10 'Pt plod on or above - A - fine SV -kli died. sand rib dal group maw VI plod below •A our. SP - M pocry . gaoled nand with sat Y sot contains 2 15% gravel add Nadi grave' SPS6ioorlf graded sand sib clay 10 grasp name W SIEVE ANALYSIS I SCRUM -IM f 51101 Mil i 60. - 5 5IK I % 'h 4 10 to e0 d0 1.0 700 Fee class likelier, of ttae- gr*iwel soils loo - - - - - •o awlfMe-1 dfr r.iwostiiaafcaer sa-goad / 1d. so linen Sel - z , - Edrl4tion *f '11 -Ilse I Hertmt *1 of PI -4 a LL -25.S, eo d.0 d.0 W ta tthin. PI -D -7J ILL -Z0) � ,, Z 0 40 so — Z Egua tiw _ of U -Ilot our < W o mono " . 14 d or Ytrtlal � to PI, � 1- tw lit t L .9 IL L el cc F 2. I t, ,C y - f_srun ' 40 u ui AMU/ uj us i cc W ll ,r1 MH col OH • 20 — 00 4 o„ -tear, t /MN�V .■. 11U - - o - - '00 T - -- ow OL w [.. d.....1.. L...:1, L...:1, :, 't... , tt 7r ML 50 10 5 Lo t1.5 O.tO PARTICLE SIZE IN MILLIMETRES o to PC 20 30 40 50 10 7o so 50 100 „_flit.. ,r LIQUID LIMIT (Ll) C, -. - co - oo cr_-i It.il - s s NM A„ a D. ■ 0.... ,. e 7S 4114 5!MCt r&R �• KEY TO BORING LOG SOIL CLASSIFICATION Particle Size and Proportion • Verbal descriptions are assigned to each soil sample or stratum based on estimates of the particle size of each component of the soil and the percentage of each component of the soil. Particle Size Proportion Descriptive Terms Descriptive Terms Soil Component Particle Size Component Term Percentage Boulder > 12 inch Major Uppercase Letters >50% opt Cobble 3 — 12 inch (e.g., SAND, CLAY) Gravel- Coarse 3 /4 - 3 inch -Fine #4 — 3 /4 inch Secondary Adjective 20 % -50% Sand - Coarse #10 - #4 (e.g. sandy, clayey) - Medium #40 - #10 -Fine #200 - #40 Minor Some 15 % -25% Silt (non- cohesive) < #200 Little 5 % -15% Clay (cohesive) < #200 Trace 0 % -5% Notes: 1. Particle size is designated by U.S. Standard Sieve Sizes 2. Because of the small size of the split spoon sampler relative to the size of gravel, the true percentage of gravel may not be accurately estimated. Density or Consistency The standard penetration resistance values (N- values are used to describe the density of coarse - grained soils (GRAVEL, SAND) or the consistency of fine - grained soils (SILT, CLAY). Sandy silts of very low plasticity may be assigned a density instead of a consistency. DENSITY CONSISTENCY Term N -Value Term N -Value Very Loose 0 — 4 Very Soft 0 — 1 Loose 5 — 10 Soft 2 — 4 Medium -Dense 11 — 30 Medium Stiff 5 — 8 Dense 31 — 50 Stiff 9 — 15 Very Dense > 50 Very Stiff 16 — 30 Hard >30 Notes. +�► 1. The N -value is the number of blows of a 140 Ib. hammer freely falling 30 inches required to drive a standard split - spoon sampler (2.0 in. 0 D , 1 -3/8 in. I.D.) 12 inches into the soil after properly seating the sampler 6 inches. 2. When encountered, gravel may increase the N -value of the standard penetration test and may not accurately �,,, represent the in -situ density or consistency of the soil sampled. _ oar v 0 *sr e- ( CD V L O irti N 4 E' , .. , Q. 0 E 0 co `° CD > +rr O a E °' E D _ E o F ° �� so O U co ci .c o E .� CD U irr U d E a) 15 = U .X o n �' y 2 Q C d see ai E ° c m o ▪ ca c o (1) d 2 N N > cD Q) • _0 E) a) aj N c0 O (n V t` O ,_ E aaZ N O Ce > y cC . 'a a H z Y gs o E. x a) o L. O in r N 0) O ... O (0 C ✓ c C CL CL 0 .c A U ,� CD (a O J ic) E Cr) 10 L co N c0 w LL — J ID D E o 1n Q. d' LO yr J J 0 2 i (1) 0 2 Bow D "" L- C 7 w LO O c0 V c7 N 10 10 Or N C o V N c (D O c7 c c7 L () r- (D O O N (7 LO 10 CO 2 U 0 . . _ _ . rn M E ^ U7 c- ( 17 r- ii1W a N N: ' N N� t() P.- 0 ---' ',-- (.0 CO = CD CO CO CO a) a -o r L E E co y -o — co - (n d E cn Z O .. . Z iao w Q) a) (.) C- r- •,-- •c N N N N • O • - CD m m m m CD m m m Z CL Om 411111 GRAIN SIZE DISTRIBUTION REPORT - N N O O O O O p M u It 4 ii it 100 -- -------- ... ■ 90 1- . - . . ;-- . - - r — taw : ; . : : : ; z 50 : : : : : : : am w • two w 40 : : . : : : : : : : ; a , . . , . , 30 : ; : : : ; .. . We 20 - - - . . . . . _ - . . . _ .� 10 : : : : : : ; • ; _ . 0 . - -: ' : - - - - '- - - - - - ' - 1 , N„ 100 10 1 0.1 0.01 0.001 GRAIN SIZE (mm) % GRAVEL % SAND % SILT /CLAY tom 36.4 17.2 46.5 SIEVE PERCENT SPEC PASS? Soil Description SIZE FINER PERCENT (X =NO) light brown silty GRAVEL, some sand me 1 1 /2 in 100.0 1 in 100.0 Atterberq Limits 3/4 in 100.0 LL= 40 PL= 29 Pl= 11 "" 1/2 in 85.7 3/8 in 76.5 #4 63.6 Coefficients _ wils #8 60.6 085= 12.422 D00= 2.157 D50= 0.210 #10 59.5 D30 D15 D10 #16 57.2 C C w. #30 54.1 #40 52.6 #50 51.4 Classification wt . #100 48.7 USCS= GM AASHTO= #200 46.5 Remarks w Moisture Content= 14.5 % Specific Gravity= Sample No.: 1 Date: 6/11/04 "` Location: B -1 Elev /Depth: 1 ft to 2.5 ft Client: Hazen and Sawyer, P.C. ... r&R Froehlin and g Project: Moore's Creek WWTP Improvements Robertson, Inc. Location: Charlottesville, Virginia WO 1^°1 Project No.: F71 -039G .. GRAIN SIZE DISTRIBUTION REPORT C E E _ o O 0 0 0 CC ow w , . , , w 40 : ; : : • • : : : : 30 : : : ; 20 . . . . . . — 10 : ; : : : : : : : a. 100 10 1 0.1 0.01 0.001 GRAIN SIZE (mm) GRAVEL % SAND % SILT /CLAY ..e 0.0 20.9 79.1 SIEVE PERCENT SPEC PASS? Soil Description me SIZE FINER PERCENT (X =NO) brown sandy elastic SILT 1 1/2 in 100.0 1 in 100.0 Atterberq Limits 3/4 in 100.0 LL= 55 PL= 35 PI= 20 f1° 1/2 in 100.0 3/8 in 100.0 #4 100.0 Coefficients .+r #8 97.2 DB5= 0.196 D6o= Dso= #10 96.5 D30 D15 D10 #16 95.1 C C r. #30 91.7 #40 89.9 #50 88.0 Classification im„ #100 83.1 USCS= MH AASHTO= #200 79.1 Remarks Moisture Content= 55.7 % .r Specific Gravity= Sample No.: 3 Date: 6/11/04 air Location: B -2 Elev /Depth: 6 ft to 7.5 ft Client: Hazen and Sawyer, P.C. .. F-8(R Froehling an Project: Moore's Creek WTP Improvements Robertson, W Inc. Location: Charlottesville, Virginia , . a a , Project No.: F71 -039G .r. y1NJ (. E "" BORING LOG FROEHLING & ROBERTSON, INC. r8( GEOTECHNICAL • ENVIRONMENTAL • MATERIALS ENGINEERS LABORATORIES OVER ONE HUNDRED YEARS OF SERVICE" Report No F71-039G 1 B8 Date June 16, 2004 Chem Hazen and Sawyer, P.C. Project Moore's Creek \VWTP Improvements, Charlottesville, Virginia Bonng No.. B -1 (1 of 1) Depth 20.0' Elev 373.0ft ± Location See Boring Location Plan Type of Bonng HSA Started 5 /19/04 Completed 5/19/04 Dnuer Arnold ..� DESCRIPTION OF MATERIALS * Sample Sample N Value Elevation Depth Depth low &, ftl REMARKS (Classification) Blows (feet) 372.7 - 0.3 v 4" Suficial Organic Soils /- i. Brown, Moist, Stiff, Sandy SILT (MI,), Little Gravel 5_4_5 1.0 Moisture content= 14.5% ""' • FILL 9 • 2.5 • 369.5 - 3.5 s.- — 675 3.5 • Greenish Grayish Brown, Moist, Medium Dense, �" •� GRAVEL (GM), Little Silt 5 0 17 • FILL 367.0 - 6.0 4 5_7_g 6.0 Moisture content 22.0 •• Brown, Moist, Stiff, SILT (ML), Little Sand and rr •�• Gravel 15 7.5 • • FILL 364.5 - 8.5 Reddish Tan, Very Moist, Medium Stiff, SILT (ML), 3 -4 -4 8.5 Moisture content--32.8°/0 __ = Trace Sand and Rock Fragments 8 10.0 RESIDUUM 2-3-2 13.5 Moisture content-36.4°/0 5 15.0 18.5 354.5 - 18.5 II 6 -9 I6 Brown, Moist, Very Stiff, Fine Sandy SILT (ML) 353.0 20.0 RESIDUUM 20 Q 25 Bonng Terminated at 20 Feet itrr Groundwater was not encountered during drilling rrr and upon removal of the augers Cave in depth recorded at 1 ft upon removal of the augers us 1- illy U Ids O 0 U z s „ *Number of blows required for a 140 lb hammer dropping 30" to dnve 2" O D 1 375" 1.0 sampler a total of 18 inches in three 6" increments The sum of the second and third increments of penetration is termed the standard penetration resistance, N SINC BORING LOG FROEHLING & ROBERTSON, INC. r GEOTECHNICAL • ENVIRONMENTAL • MATERIALS ENGINEERS • LABORATORIES OVER ONE HUNDRED YEARS OF SERVICE" ""` Report No F71 -039G , 8 ' Date June 16, 2004 cheat. Hazen and Sawyer, P.C. >r. Project- Moore's Creek WWTP Improvements, Charlottesville, Virginia Boring No B -2 (1 o f 1) Dep 20.0' Elev 373.0ft ± Location See Boring Location Plan Type of Bonng VISA Started 5/19/04 Completed 5/19/04 Dnller Arnold �r. DESCRIPTION OF MATERIALS * Sample Sample N Value Elevation Depth Depth lows/ ft REMARKS (Classification) Blows (feet) 0 ' ) 372.7 0.3 - ' ��4' Surficial Organic Soils l - Reddish Brown, Moist, Very Stiff, Elastic SILT 9 -12 -16 1.0 Moisture content-33 3% _ (ME), Trace Rock Fragments RESIDUUM 2.5 369.5 - 3.5 _ 25 50/6" 3.5 wt- - Tan, Moist, Very Dense, Silty Fine to Coarse SAND (SM), Little Rock Fragments 4.5 100+ RESIDUUM 367.0 - 6.0 — 20 -12 7 6.0 Moisture content 55.7 °0 - Brown, Reddish Brown, and Black, Very Moist, Very ""' _ Stiff, Elastic SILT (ME) 19 RESIDUUM 7.5 364.5 - 8.5 - - 4 -3 6 8 . 5 Moisture content-51.5% - Brown, Moist, Stiff to Hard, Fine Sandy SILT (ML) INN RESIDUUM 10.0 9 ON 4 -5 -8 13.5 Moisture content = 36.5 ° /o 15.0 13 IMO NMI 13-21-42 18.5 353.0 - 20.0 - 20.0 63 Boring Terminated at 20 Feet Groundwater was not encountered during dnlling _ and upon removal of the augers Cave in depth recorded at l 0 upon removal of the augers +trr wt- Y U NM V I C IMO *Number of blows required for a 140 lb hammer dropping 30" to dnve 2" 0 D , 1 375" 1 D sampler a total of 18 inches in three 6" increments The sum of the second and third increments of penetration is termed the standard penetration resistance, N SIN E rr. BORING LOG C FROEHLING & ROBERTSON, INC. GE f & O- ECHNICAL • ENVIRONMENTAL MATERIALS t r ENGINEERS • LABOR ;TORIES OVER ONE HUNDRED YEARS OF SERVICE" rr Report No F71 -0396 iee, Dare June 16, 2004 Chart Hazen and Sawyer, P.C. Project Moore's Creek «'WTP Improvements, Charlottesville, Virginia Bonn No B - (1 of 1) Deptlh 20.0' Elec. 373.Oft ± Location: See Boring Location Plan Type of Bonng. HSA Started 5/18/04 Completed: 5/19/04 Dnller Arnold +� DESCRIPTION OF MATERIALS * Sample Sample N Value Elevation Depth Depth REMARKS (Classification) Blows (feet) ( blows/ ft) 372.7 - 0.3 — 4" Surficial Organic Soils r • Bron, Moist, Stiff, SILT (ML), Trace Rock 5 -6 -7 1.0 w mot ; Fragments 13 • FILL 2.5 • s 369.5 3.5 3.5 • Reddish Brown, Very Moist, Soft to Medium Stiff, 2 1 -Z • Elastic SILT (M 1), With Rock Fragments 5 0 3 • FILL • • • 3 -5 -3 6.0 tor • 8 • 7.5 • 364.5 - 8.5 3 -2 -5 8.5 — Reddish Tan, Very Moist, Medium Stiff to Stiff, SILT (ML), Some Sand 7 10.0 RESIDUUM 13.5 3-3-6 15.0 9 r.. 3-5-7 18.5 353.0 - 20.0 20.0 12 �.r Boring Terminated at 20 Feet Groundwater was not encountered during dnlling ire and upon removal of the augers Cave in depth recorded at 0.5 ft upon removal of the augers .rr. row Q U � U J Z a I. *Number of blows required for a 140 lb hammer dropping 30" to drive 2" 0 D , 1 3 1 D sampler a total of 13 inches in three 6" increments The sum of the second and third increments of penetration is temed the standard penetration resistance, N. UM {- 1 W Z CC Q D J LD z CL F, va 1— N'OOI�I U Z Z U O d W W O o 1 --■1011 L.. o ‘..1.1) Z < W O rc 3 OD w o CC S U n F- Q Z 40 K CC ¢ W Q Z a o 0 a o Cc 1— W W cc 0 CL AA I F- o 9.. o B -3 -- 1 4 , \ \\ 7 1 11i 3.< i- 1 c a z C / v Y z_ I \� CC ¢ 0 UM Cr ii 1 [ 0 Y=t I 1 1 , a B -2 r o r a _o - -- i� a ) I 3 1.....1 i ll O? ■ ¢ V I a X2 L._ 1.1 C1 I - I ____ Br, L.1 ,a 1 ' f- i )3 i t z 01 1 _ L. � l l y I , I I I S I I d V ,_—__ Eti - r - lk �J l'1 i o 0 waf° V' w U i i ® I I O m 1 N;; ; 1 I' 2 � i M I I 4 I 0' Z _1 : 41...illilim B_i ii -- EE 0 i •• r -- ' --- ter: 7 r _ W ES J fit. n 0 � I � 00 W Z u Z J 1 Z Z U Tom_ ' ; . FE m �1 a 11111M u, i 1 a — L .1 I 1 , ,r, ,. i! .■ 40 : 0 Ow 1 ,■ n ✓ g N SiIICE N NW r FROEHLING & ROBERTSON, INC. DATE: June 16, 2004 9 C &p. GEOTECHNICAL • ENVIRONMENTAL • MATERIALS SCALE: 1 " - 20' ENGINEERS • LABORATORIES o wl 69, ° " OVER ONE HUNDRED YEARS OF SERVICE" DRAWN: repro F71 -039G I Moore's Creek WWTP Improvements BORING DRAWING NO. LOCATION ...Albemarle County, Virginia PLAN 2