PROJECT CULVERT REPLACEMENTS GEOTECHNICAL ENGINEERING REPORT CONTRACT No WO01 PALM BEACH COUNTY, FL FEBRUARY 2013

Transcription

1 SOUTH FLORIDA WATER MANAGEMENT DISTRICT PROJECT CULVERT REPLACEMENTS GEOTECHNICAL ENGINEERING REPORT CONTRACT No WO01 PALM BEACH COUNTY, FL FEBRUARY 2013 Prepared for: South Florida Water Management District 3301 Gun Club Road West Palm Beach, Florida Prepared by:

2 Fort Lauderdale Port Saint Lucie Sarasota West Palm Beach South Florida Water Management District February 22, Gun Club Road Project No. WPB West Palm Beach, Florida BG 21.1 Attention: Subject: Ms. Sara Sciotto, P.E. Geotechnical Engineering Report - Final Project Culvert Replacements Contract No WO01 South Florida Water Management District Dear Ms. Sciotto: Pursuant to the requirements of Work Order WO 01, Dunkelberger Engineering & Testing, Inc. (Dunkelberger) has completed a program of subsurface exploration and geotechnical engineering related to the Project Culvert Replacement project, which is situated at five locations in Palm Beach County, Florida. The following reports present descriptions of the methods of exploration, factual data obtained from the work and geotechnical engineering recommendations for design and construction of the culverts. Dunkelberger s Quality Certificate of Compliance follows this cover letter. One report has been developed for each of the five sites. The reports are tabbed for ease of reference as follows: Tab 1 - PC-01 Tab 2 - PC-03 Tab 3 - PC-05 Tab 4 - PC-06 Tab 5 - PC-18 This report includes Dunkelberger s responses to comments provided by District staff related to the draft of this report, which was submitted on February 15, We trust that the information provided herein is clearly presented and easily understood. Should you have any questions regarding the contents of this report, please contact the undersigned. Very truly yours, DUNKELBERGER ENGINEERING & TESTING, INC. Kevin E. Aubry, P.E. Geotechnical Services Manager FL Registration No State of Florida Board of Professional Engineers Authorization No Toll Free (877)

3

4 PC-01

5 Fort Lauderdale Port Saint Lucie Sarasota West Palm Beach South Florida Water Management District February 22, Gun Club Road Project No. WPB West Palm Beach, Florida BG 21.1 Attention: Subject: Ms. Sara Sciotto, P.E. Geotechnical Engineering Report Project Culvert Replacements PC-01 Contract No WO01 South Florida Water Management District Dear Ms. Sciotto: INTRODUCTION Pursuant to the requirements of Work Order WO 01, Dunkelberger Engineering & Testing, Inc. (Dunkelberger) has completed a program of subsurface exploration and geotechnical engineering related to Project Culvert PC-01, located along the west bank of the L8 Canal in Palm Beach County, Florida. This report presents a description of the methods of exploration, factual data obtained from the work and geotechnical engineering recommendations for design and construction of the culvert. PROJECT CONSIDERATIONS The project site consists of a levee that runs along the west bank of the L8 Canal. The subject area is located approximately 6.2 miles north and west of Southern Boulevard/US 441/US 98/SR 80. The project vicinity map is provided on Figure 1. The site includes an existing culvert structure consisting of a single barrel 72-inch diameter Corrugated Metal Pipe. The existing pipe is severely corroded and therefore in need of replacement. The culvert structure originally had a flap gate on the upstream end, however it was removed and the concrete structure that supported the flap gate is collapsing. North of the culvert structure, the roadway splits into two parallel roadway embankments. The westernmost roadway is considered to be the West L8 Levee. The following photograph depicts the West L8 Levee, north of the culvert structure. West L8 Levee, North of PC-01, Viewing Northwest State of Florida Board of Professional Engineers Authorization No Toll Free (877)

6 Project Culvert Replacements PC-01 Page 2 February 22, 2013 Based upon the Statement of Work, the South Florida Water Management District (SFWMD) plans to construct a new 72-inch diameter Corrugated Aluminum Pipe (CAP) and a manually operated slide gate and a temporary by-pass road. The new culvert is to have an invert elevation of feet with respect to the North American Vertical Datum of 1988 (NAVD). SOIL SURVEY Information available from the U.S. Department of Agriculture Soil Conservation Service Soil Survey of Palm Beach County, Florida [1978] (SCS) depicts the project site to be predominantly mapped as Arents, very steep, Oldsmar sand, and Holopaw fine sand units. These map units are described below. Arents, very steep, is an excessively drained, sandy soil found in long narrow ridges along the canals. The soil was formed in dominantly sandy material that was excavated from canals and deposited along the banks. Grayish brown sands are found in the upper 5 inches followed by light grayish brown sand from 5 to 28 inches. Below this layer, very dark gray sand typically extends for 8 inches, followed by pale brown sand from 36 to 50 inches. A mixture of pale brown sand with shell and limestone fragments extends from 50 to 80 inches. The water table is generally below a depth of 60 inches. Oldsmar sand is a poorly drained, nearly level soil found in broad, flatwood areas. The typical soil profile consists of sands to a depth of about 30 inches followed by a weekly cemented layer over a loamy layer. The water level in the Oldsmar sand map unit is within a depth of 10 inches for 1 to 3 months during wet seasons and between the depths of 10 to 40 inches for a period of 6 months or longer. Holopaw fine sand is a poorly drained, nearly level soil found on broad, low-lying flats and in depressional areas. Fine sands are typically found in the upper 40 inches followed by loamy subsoil extending to 72 inches. Under natural conditions, the SCS reports that the water table is within 10 inches for 2 to 6 months. The depressions are ponded for 6 months or more in most years. Field Explorations SUBSURFACE CONDITIONS The field exploration consisted of drilling Standard Penetration Test (SPT) borings at two locations, one on the levee bench north of the existing culvert (TB-1) and one on the levee crest south of the culvert (TB-2). Additionally, auger borings were drilled at two locations along the West L8 Levee crest, one approximately 540 feet northwest of the culvert and the other approximately 800 feet northwest of the existing pipe. The boring locations were marked in the field with wooden stakes and were estimated using a hand held GPS unit. Locations of the borings are provided on the attached Figure 2. GPS coordinates (i.e. Latitude and Longitude) for the boring locations are shown in the following table. SPT Boring (TB) Latitude Longitude Hand Auger Boring (AB) Latitude Longitude 1 N ' W ' 1 N ' W ' 2 N ' W ' 2 N ' W '

7 Project Culvert Replacements PC-01 Page 3 February 22, 2013 The boring locations were determined in the field by Dunkelberger. At each location the ground surface elevation was approximated from the topographical survey provided by Erdman Anthony. The ground surface elevations at the boring locations are shown on the attached Figure 2 and are referenced to NAVD. Standard Penetration Test Borings Subsurface conditions were explored using two (2) Standard Penetration Test (SPT) borings, drilled in accordance with ASTM D 1586 protocol. A truck mounted Central Mine Equipment (CME) Model 45 drilling rig was utilized to access the boring locations and to drill the borings. Boring TB-1 was drilled to 30 feet below surface grade, while boring TB-2 was drilled to 50 feet below land surface. Samples of the subsurface materials were obtained continuously for the full depth of each boring. Groundwater levels were recorded for each SPT boring. The boreholes were sealed with neat cement grout in a bottom-to-top manner upon completion of each boring. The following is a photograph of the CME model 45 drilling rig.. CME Model 45 drilling rig at Boring TB-2 Auger Borings Additionally, the subsurface conditions were explored using two auger borings drilled using a truck-mounted CME Model 45 drilling rig. Auger borings AB-1 and AB-2 were drilled to 10 feet below grade. Samples of the subsurface materials were obtained continuously for the full depth of each boring. Groundwater was not found at the time of the drilling in either of the auger borings. The boreholes were sealed with cement grout in a bottom-to-top manner upon their completion.

8 Project Culvert Replacements PC-01 Page 4 February 22, 2013 Stratigraphy Subsurface components found in the borings generally consisted of levee fill materials (i.e. sand with trace shell fragments and gravel) over sand and then silty, sandy limestone. Slightly silty to silty sand was found below the limestone followed by sand with trace to slight amounts of silt. The following table provides a description of the various strata found in the borings. Table 1 - Stratigraphy Stratum No. Material Description 1 Light gray-brown to dark gray-brown fine to medium SAND, trace silt, trace shell fragments, some clayey sand lenses, gravel, trace organic matter, some roots in upper 12 inches (SP, SP-SM) (LEVEE FILL) 2 Light brown to gray-brown fine to medium SAND, trace silt (SP, SP-SM) 4 Gray fine to medium SAND, trace to some clay, some iron oxide staining (SP-SC, SC) 7 Light gray to gray fine to medium SAND, trace to some silt, shell fragments (SP, SP-SM) 8 Light gray to dark gray silty, sandy LIMESTONE, shell fragments, weakly to well cemented 10 Gray to dark gray SAND, slightly silty to silty, with shell fragments and gravel (SP-SM, SM) 11 Dark gray fine to medium SAND, trace to some shell fragments (SP, SP-SM) Note: Strata 3, 5, 6, and 9 as shown in the Legend on attached Figure 2 were not found in the borings associated with PC-01 and therefore are not included in this table. The Standard Penetration Test (SPT) is completed by dropping a 140-pound hammer for a vertical distance of 30 inches and summing the number of hammer blows required to drive a 2-inch diameter split barrel sampler a distance of 12 inches (the SPT after ASTM D 1586). The results of the SPT data were used to estimate the relative density of granular soils and the relative hardness of the limestone formation. The table that follows provides a description of each subsurface component, and the range and average SPT N-Values for each of the subsurface components. Table 2 Relative Density Stratum No. Material Description 1 SAND (LEVEE FILL) 2 SAND with clay 4 SAND with shell 7 SAND 8 LIMESTONE 10 SAND with silt 11 SAND Range of SPT N-Values (blows/foot) 5 to 20 Average to 28 Average 20 9 to 15 Average 12 2 to 16 Average 11 89/9 to 50/2 Average 80/6 6 to 17 Average to 35 Average 29 Relative Density/ Consistency/ Hardness Loose to Medium Dense Medium Dense Loose to Medium Dense Very Loose to Medium Dense Very Well Cemented/Hard Loose to Medium Dense Medium Dense to Dense

9 Project Culvert Replacements PC-01 Page 5 February 22, 2013 The subsurface profiles for the SPT and auger borings are provided on Figure 2. Detailed drilling logs are provided in Appendix A. Groundwater Groundwater was measured in the borings on the dates that the borings were drilled (January 10, 2013). Based upon estimated ground surface elevations at each boring location, and the measured depths to groundwater, the groundwater elevations at the time of drilling were estimated to be and feet NAVD for TB-1 and TB-2, respectively. Groundwater was not found while drilling AB-1 and AB-2. The groundwater levels reported herein are indicative of the groundwater levels in the boreholes at the time of drilling. Water table levels on the site are expected to fluctuate in response to a variety of factors, including rainfall and surface water levels within the adjacent canals. LABORATORY TEST RESULTS Soil samples obtained from the borings were examined by a geotechnical engineer and classified in accordance with the Unified Soil Classification System (ASTM D 2487). Representative samples from the borings were tested for moisture content (ASTM D 2261), and grain-size distribution (ASTM D 422). The test results are summarized in the following table. Boring No. Depth (feet) Table 3 - Summary of Laboratory Test Results Moisture Amount Passing Sieve Size (%) Stratum Content No. (%) No. No. No. No. No. 3/4 3/ TB TB TB TB TB TB The grain size distribution tests indicate that the samples from Stratum 2 have approximately 95 percent passing through the No. 40 Sieve, indicating that these soils are mostly fine grained sand. The sample from the clayey sand (Stratum 4) has a fines content (i.e. amount passing the U.S. Standard No. 200 Sieve) of approximately 16 percent. The sample from Stratum 7 has a fines content of approximately 5 percent, indicating trace silt. The Stratum 10 soils have a gravel content (i.e. the amount retained by the US Standard No. 4 Sieve) of approximately 12 percent as well as a fines content of approximately 7 percent. The Stratum 11 soils have approximately 76 percent passing through the No. 40 Sieve, indicating fine to medium grained sands. No. 200 (THIS SPACE INTENTIONALLY LEFT BLANK)

10 Project Culvert Replacements PC-01 Page 6 February 22, 2013 General Overview GEOTECHNICAL RECOMMENDATIONS The explorations for this study indicate the site of the proposed PC 01 culvert replacement project is generally underlain by moderately thick deposits of loose to medium dense sands, and sand-shell mixtures over a formation of very well cemented limestone and then loose to medium dense sands. These subsurface profile conditions are considered to be favorable for the planned construction from a geotechnical engineering point-of-view. Materials found in the borings at the proposed culvert invert elevation consisted of loose to medium dense sands with silt and shell fragments. The proposed culvert may be supported on grade. Headwalls associated with the culvert may be supported on conventional spread footing foundations designed for a modest bearing capacity of 2,500 pounds per square foot (psf), or may consist of steel sheet piling. Excavations Unbraced excavations should be made in accordance with all applicable State and Federal requirements. More specifically, OSHA 29 CFR part 1926 (Subpart P, Excavations) defines the subsurface profile, within the planned depths of excavation, as a sand (Type C soil). The OSHA document states that Type C soils will remain stable when cut on a 1.5 horizontal to 1 vertical slope (1.5H:1V). However, borings drilled for this study indicate that subsoils will not be stable when cut in accordance with the minimum OSHA requirements. For these reasons, we recommend that temporary, fully dewatered excavation slopes be cut no steeper than 2H:1V. Where such excavation slopes cannot be established due to space restrictions, then steeper, braced (sheeted) side slopes will be required. Excavation bracing should be designed by an experienced structural engineer working in concert with the general contractor for the project. Lateral Earth Pressure Design Criteria The following soil parameters should be utilized for estimation of lateral earth pressures in the design of earth retaining structures, including temporary steel sheet piling. Table 4 Lateral Earth Pressure Design Criteria - PC-01 Material Elevation γ moist γ sat Φ C K A K P Type (feet) (pcf) (pcf) (degrees) (psf) SAND +22 to LIMESTONE +1 to SAND -6 to SAND -22 to Notes: 1. Depth refers to below ground surface at boring locations. 2. γ moist, γ sat, Φ and C refer to moist unit weight, saturated unit weight, angle of internal friction, and cohesion, respectively. 3. K A and K P refer to the coefficients of active and passive lateral earth pressure, respectively. The value shown for K P is based upon ultimate, and should be factored for safety. 4. Hydrostatic and surcharge loads should be incorporated into the design as appropriate.

11 Project Culvert Replacements PC-01 Page 7 February 22, 2013 Owing to the hardness of the limestone formation, we anticipate that sheet pile installation will require preforming through the rock if the required sheet pile tip elevations are within or below the bottom of the rock. The values given for the limestone formation are in anticipation of an installation method that includes preforming (i.e. pre-augering) in order to facilitate installation of the sheeting into the well cemented formation of limestone. Dewatering Given a proposed culvert invert elevation of feet NAVD, dewatering will be necessary for in the dry construction of the culvert and associated earthwork. In order to prepare the base of the excavation, the dewatering should be capable of lowering the groundwater level to at least three feet below the bottom of the excavation at all times. The dewatering system should be designed by an experienced hydrogeologist under the employ of the general contractor. The proximity of the L8 Canal should be considered in the design of the dewatering system. Dewatering should be continued until the backfill is at least 3 feet above the water table elevation. Termination of the dewatering should be controlled such that the water table is allowed to rise at a rate equal to the total number of feet it was lowered divided by ten hours but not more than 1 foot/hour. Culverts The proposed 72-inch diameter CAP culvert may be constructed on grade. Ground preparation in advance of placement of the pipe should consist of normal excavation to the proposed structure bottom levels. Based upon an understanding of the proposed construction and the measured depth to groundwater, we expect that the bottom of the required excavation for the culvert will be below the ambient groundwater elevation. The in-situ soils directly beneath the culvert should be compacted to at least 95% of the Modified Proctor maximum dry density to a depth of 18 inches. Based on the results of the SPT borings, the in-situ soils at the proposed structure s foundation level are expected to be sand with trace to slight amounts of silt, and broken shell. In the event that the foundation soils are over excavated by more than 6 inches, a bedding material consisting of a coarse aggregate as specified in FDOT Section 901 for Aggregate Size Number 89, 8, 78, 68, 6 or 57 should be used to restore the excavation to proper grade. The gravel bedding material should be fully enveloped (wrapped) with an FDOT Type D-4 filter fabric, as specified in FDOT Standard Index No The coarse aggregate should not extend within 4 feet of the ends of the trench unless a cutoff such as a turn-down on the headwall foundation is used to cutoff seepage. Backfill and Compaction Backfill placed from the bottom of the excavation to pipe springline should consist of sands having an SP or SP-SM classification in accordance with ASTM D 2487 (Unified Soil Classification System). Above the springline, backfill adjacent to the new culvert should consist of sands or sand-gravel mixtures, having a maximum size of 1 inch, not more than 2 percent (by weight organic matter) and a maximum of 10 percent passing the U.S. Standard No. 200 Sieve.

12 Project Culvert Replacements PC-01 Page 8 February 22, 2013 From the bottom of the excavation to 12 inches above the pipe, the backfill should be placed in horizontal lifts, evenly distributed on both sides of the pipe, not greater than 6 inches thick (loose measure), and each lift should be compacted to not less than 95 percent of the maximum dry density determined in accordance with Modified Proctor (ASTM D 1557). Above this, the backfill may be placed in horizontal lifts not exceeding 12 inches in loose thickness. Extra care should be exercised to obtain compaction beneath pipe haunches. Groundwater should be lowered and maintained at least 3 feet below the proposed structure bottom levels until the fill is has been placed and compacted at least 3 feet above the position of the normal water level. Headwalls The culvert headwalls may be supported on conventional shallow spread footing foundations, and be designed and proportioned for a net allowable soil bearing pressure of 2,500 psf. Foundation soil preparation should be completed as described in the section of this report related to the culvert. The walls should be carefully backfilled such that they are not subjected to lateral pressures that exceed those used in the design. Backfill within 3 feet of the wall should consist of sands with less than 10% passing the U.S. Standard No. 200 sieve. The backfill should be placed in loose lifts not exceeding 6 inches in thickness and should be uniformly compacted to at least 95% of the Modified Proctor maximum density. Only light, hand-operated equipment (weighing less than 1,000 pounds) should be used within 5 feet of the back of the walls to avoid developing excessive lateral earth pressures. Filter fabric should be placed over any wall joints, seams, drains or openings that will permit the passage of water in order to prevent the migration (piping) of the retained soils. Beyond the described 3-foot envelop, backfill should consist of sands or sand-gravel mixtures, having a maximum size of 1 inch, not more than 2 percent (by weight organic matter) and a maximum of 10 percent passing the U.S. Standard No. 200 Sieve. The backfill may be placed in loose lifts not exceeding 12 inches in thickness and should be uniformly compacted to at least 95% of the Modified Proctor maximum density. Recommended parameters for design of the headwall are summarized in the following table. Condition of Wall Movement Table 5 Design Criteria for Headwall Backfill Friction Unit Weight (pcf) Angle, φ Submerged (degrees) Moist Soil Soil Earth Pressure Coefficient Restrained against rotation (at-rest) Wall rotates away from the retained soil at least 0.1% of the total wall height (active) Note: The above values reflect earth pressure due solely to the backfill specified herein. The design should also account for lateral pressure due to unbalanced hydrostatic forces and surcharge loads.

13 Project Culvert Replacements PC-01 Page 9 February 22, 2013 The design parameters are based on the following assumptions: A permanent drainage system will be installed behind the wall that prevents development of hydrostatic pressure. Horizontal backfill. Sloping ground conditions on either side of the wall should be accounted for in the design. No surcharge loads will be applied. No safety factor is included. If the new headwall is designed without a drainage system, then additional forces from hydrostatic pressure induced behind the wall will need to be accounted for in the design. We recommend that these calculations assume that the backfill soils can become saturated up to the top of canal bank elevation. For analysis of sliding resistance of the base of the retaining wall, the ultimate coefficient of friction may be taken as 0.4 for the soils. The force which resists the sliding is calculated by multiplying the normal force on the base by the coefficient of friction. Full development of the frictional force could require displacement of the base of roughly 0.1 to 0.3 inch. Slope Restoration Areas of the canal banks that are disturbed during the construction process will need to be restored. We understand that the design of armoring of the slopes will be provided by the SFWMD. As a minimum, we have assumed that the canal banks will be returned to their original stable slope angle and the exposed bank soils will be protected through the use of rip rap, articulated concrete mats or other such means. LIMITATIONS This culvert replacement study has been completed for the South Florida Water Management District (SFWMD). The reported data reflects conditions at the time the borings were drilled at the locations and depths indicated. It should be recognized that subsurface conditions may differ locally from those shown by borings. If differing conditions are found during construction, Dunkelberger should be notified immediately to determine if a change in recommendations is required. Dunkelberger warrants that the recommendations presented in this report are based upon recognized practices in the disciplines of soil mechanics, foundation engineering and engineering geology. No other warranties are expressed or implied. Discussions provided herein related to construction dewatering and excavation support are for the use of SFWMD for planning purposes only. Contractors bidding this job should align themselves with an experienced hydrogeologist and structural engineer for the design of the construction dewatering means and methods, and excavation bracing systems, respectively. Such work is beyond the scope of this work order. ooo

14 Project Culvert Replacements PC-01 Page 10 February 22, 2013 We trust the information provided herein is sufficient for this phase of the project. Should you have any questions regarding the contents of this report, please call. Very truly yours, DUNKELBERGER ENGINEERING & TESTING, INC. Daniel J. Marieni, E.I. Staff Engineer Kevin E. Aubry, P.E. Geotechnical Services Manager FL Registration No Attachments: Figure 1 Vicinity Map Figure 2 Boring Location Plan and Subsurface Profiles Appendix A Detailed Drilling Logs

15

16

17 APPENDIX A DETAILED DRILLING LOGS

18 DUNKELBERGER ENGINEERING & TESTING, INC. TEST BORING LOG BORING NO. TB-1 Project: SFWMD Culverts PC01 Sheet No.: 1 of 1 Client: SFWMD Project No.: WPB Boring Location: See Boring Location Plan Casing Rock Core Elevation: Type: None None Boring Depth: 30 GPS coordinates: Diam: Water Depth: N Depth: Drilled Date: 1/10/ W Drill Rig: CME 45 Driller: BP, MQ, CN Contractor: Dunkelberger Logged By: DM Depth Blows On Sample N Sample Sample Munsell Material Description (ft) Spoon Per 6 Value No. Interval Color YR 4/3 Fine SAND, trace silt, trace shell fragments, trace roots, trace organics (SP,SP-SM) YR 5/3 Fine to medium SAND, gravel, and shell fragments (SP) YR 5/3 Fine to medium SAND, gravel, shell fragments (SP) YR 5/3 Fine to medium SAND, gravel, shell fragments (SP) YR 6/8 Fine SAND (SP) YR 6/8 Fine SAND (SP) YR 8/2 Fine SAND (SP) YR 7/3 Fine to medium SAND (SP) YR 7/1- Clayey SAND, iron oxide staining (SC) 6/ YR 6/4 Fine to medium SAND, trace clay, trace iron oxide staining (SP-SC) YR 6/4 Fine to medium SAND, trace clay, trace iron oxide staining (SP-SC) YR 7/3 Fine SAND, trace silt, shell fragments (SP, SP-SM) YR 7/1 Fine to medium SAND, trace silt, shell fragments (SP, SP-SM) YR 7/1 Fine to medium SAND, trace silt, shell fragments (SP, SP-SM) YR 7/1 Fine to medium SAND, trace silt, shell fragments (SP, SP-SM) /0.5 90/ YR 7/1 Silty sandy LIMESTONE, trace shell fragments, well cemented /3 50/ YR 7/1 Silty sandy LIMESTONE, trace shell fragments, well cemented /2 50/ YR 7/1 Silty sandy LIMESTONE, trace shell fragments, well cemented /4 50/ YR 7/1 Silty sandy LIMESTONE, trace shell fragments, well cemented YR 7/1 Silty sandy LIMESTONE, trace shell fragments, well cemented 28 50/3 50/ YR 7/1 Very silty fine SAND, trace shell fragments, gravel (SM) YR 7/1 Very silty fine SAND, shell fragments, gravel (SM) Boring Terminated at Borehole Grouted DET 52 (Rev. 05/13/2008)

19 DUNKELBERGER ENGINEERING & TESTING, INC. TEST BORING LOG BORING NO. TB-2 Project: SFWMD Culverts PC01 Sheet No.: 1 of 2 Client: SFWMD Project No.: WPB Boring Location: See Boring Location Plan Casing Rock Core Elevation: Type: None None Boring Depth: 50 GPS coordinates: Diam: Water Depth: N Depth: Drilled Date: 1/10/ W Drill Rig: CME 45 Driller: BP, MQ, CN Contractor: Dunkelberger Logged By: DM Depth Blows On Sample N Sample Sample Munsell Material Description (ft) Spoon Per 6 Value No. Interval Color YR 5/3 Fine to medium SAND, trace silt, trace shell fragments, trace roots, trace organics (SP, SP-SM) YR 5/4 Fine to medium SAND, trace silt, trace shell fragments (SP, SP-SM) YR 5/4 Fine to medium SAND, trace silt, trace shell fragments (SP, SP-SM) YR 5/4 Fine to medium SAND, trace silt, trace shell fragments (SP, SP-SM) YR 5/4 Fine to medium SAND, trace silt, trace shell fragments (SP, SP-SM) YR 7/1 Fine SAND (SP) YR 7/1 Fine SAND, (SP) YR 5/2 Fine to medium SAND, trace clay (SP-SC) YR 5/2 Fine to medium SAND, trace clay (SP-SC) YR 6/1 Fine to medium SAND, trace silt (SP, SP-SM) YR 6/1 Fine to medium SAND, trace silt (SP, SP-SM) YR 7/2 Fine to medium SAND, trace silt, shell fragments (SP, SP-SM) YR 7/2 Fine to medium SAND, trace silt, shell fragments (SP, SP-SM) YR 7/2 Fine to medium SAND, trace silt, shell fragments (SP, SP-SM) YR 7/2 Fine to medium SAND, trace silt (SP, SP-SM) YR 7/2 Fine to medium SAND, trace silt (SP, SP-SM) YR 6/2 Fine to medium SAND, trace silt, shell fragments (SP, SP-SM) YR 7/2 Silty SAND, trace shell fragments (SM) /3 87/ YR 7/1 Silty sand sized LIMESTONE, shell fragments, well cemented /5 50/ YR 7/1 Silty sand sized LIMESTONE, shell fragments, well cemented /4 50/ YR 7/1 Silty sand sized LIMESTONE, shell fragments, well cemented YR 7/1 Silty sand sized LIMESTONE, shell fragments, well cemented YR 6/1 Silty SAND, shell fragments (SM) YR 6/2 Silty SAND, shell fragments, gravel (SM) YR 6/1 Silty SAND, shell fragments, gravel (SM) YR 5/1 Fine to medium SAND, trace silt, shell fragments, gravel (SM) YR 6/1 Fine to medium SAND, trace silt, shell fragments, gravel (SM) YR 6/1 Fine to medium SAND, trace silt, shell fragments, gravel (SM) (continued) DET 52 (Rev. 05/13/2008)

20 DUNKELBERGER ENGINEERING & TESTING, INC. TEST BORING LOG BORING NO. TB-2 Project: SFWMD Culverts PC01 Sheet No.: 2 of 2 Client: SFWMD Project No.: WPB Boring Location: See Boring Location Plan Casing Rock Core Elevation: Type: None None Boring Depth: 50 GPS coordinates: Diam: Water Depth: N Depth: Drilled Date: 1/10/ W Drill Rig: CME 45 Driller: BP, MQ, CN Contractor: Dunkelberger Logged By: DM Depth Blows On Sample N Sample Sample Munsell Material Description (ft) Spoon Per 6 Value No. Interval Color YR 6/2 Silty SAND, shell fragments, gravel (SM) YR 6/1 Silty SAND, shell fragments, gravel (SM) YR 6/1 Fine to medium SAND, shell fragments (SP, SP-SM) YR 6/2 Fine to medium SAND, shell fragments (SP, SP-SM) YR 6/2 Fine to medium SAND, trace shell fragments (SP, SP-SM) Boring Terminated at Borehole Grouted DET 52 (Rev. 05/13/2008)

21 DUNKELBERGER ENGINEERING & TESTING, INC. TEST BORING LOG BORING NO. AB-1 Project: SFWMD Culverts PC01 Sheet No.: 1 of 1 Client: SFWMD Project No.: WPB Boring Location: See Boring Location Map Casing Rock Core Elevation: Type: None None Boring Depth: 10 GPS coordinates: Diam: Water Depth: > N Depth: Drilled Date: 1/10/ W Drill Rig: CME 45 Driller: BP, MQ, CM Contractor: Dunkelberger Logged By: DM Depth Blows On Sample N Sample Sample Munsell Material Description (ft) Spoon Per 6 Value No. Interval Color 1 N/A N/A N/A Gravel, limestone, scattered outcroppings N/A N/A YR 6/4 Fine SAND, trace silt, trace shell fragments (SP, SP-SM) N/A N/A YR 7/3 Fine SAND, trace silt, trace shell fragments (SP, SP-SM) Boring Terminated at Borehole Grouted DET 52 (Rev. 05/13/2008)

22 DUNKELBERGER ENGINEERING & TESTING, INC. TEST BORING LOG BORING NO. AB-2 Project: SFWMD Culverts PC01 Sheet No.: 1 of 1 Client: SFWMD Project No.: WPB Boring Location: See Boring Location Map Casing Rock Core Elevation: Type: None None Boring Depth: 10 GPS coordinates: Diam: Water Depth: > N Depth: Drilled Date: 1/10/ W Drill Rig: CME 45 Driller: BP, MQ, CM Contractor: Dunkelberger Logged By: DM Depth Blows On Sample N Sample Sample Munsell Material Description (ft) Spoon Per 6 Value No. Interval Color 1 N/A N/A N/A Gravel, limestone, scattered outcroppings 2 3 N/A N/A YR 8/2 Fine Sand (SP) N/A N/A YR 6/4 Fine Sand (SP) 8 9 N/A N/A YR 3/2 Fine Sand (SP) 10 N/A N/A YR 4/2 Fine Sand (SP) Boring Terminated at Borehole Grouted DET 52 (Rev. 05/13/2008)

23 PC-03

24 Fort Lauderdale Port Saint Lucie Sarasota West Palm Beach South Florida Water Management District February 22, Gun Club Road Project No. WPB West Palm Beach, Florida BG 21.1 Attention: Subject: Ms. Sara Sciotto, P.E. Geotechnical Engineering Report Project Culvert Replacements PC-03 Contract No WO01 South Florida Water Management District Dear Ms. Sciotto: INTRODUCTION Pursuant to the requirements of Work Order WO 01, Dunkelberger Engineering & Testing, Inc. (Dunkelberger) has completed a program of subsurface exploration and geotechnical engineering related to Project Culvert PC-03, located along the west bank of the L15 Canal in Palm Beach County, Florida. This report presents a description of the methods of exploration, factual data obtained from the work and geotechnical engineering recommendations for design and construction of the culvert. PROJECT CONSIDERATIONS The project site consists of a levee that runs along the west bank of the L15 Canal. The subject area is located along Brown s Farm Road (State Road (SR) 827)), approximately 10.8 miles south of the intersection of County Highway 880 and SR 827. The project vicinity map is provided on Figure 1. The site includes an existing culvert structure, which consists of three 66 inch diameter Corrugated Metal Pipes. The following photograph depicts the West L15 Levee. East Side of West L15 Levee, Viewing Northwest along Brown s Farm Road State of Florida Board of Professional Engineers Authorization No Toll Free (877)

25 Project Culvert Replacements PC-03 Page 2 February 22, 2013 Based upon the Statement of Work, the South Florida Water Management District (SFWMD) plans to construct three new 66 inch Corrugated Aluminum Pipes (CAP s) and manually operated slide gates. The new culverts are to have an invert elevation of feet with respect to the North American Vertical Datum of 1988 (NAVD). SOIL SURVEY Information available from the U.S. Department of Agriculture Soil Conservation Service Soil Survey of Palm Beach County, Florida [1978] (SCS) depicts the project alignment to be predominantly mapped in Terra Ceia muck and Pahokee muck units. These map units are described below. Terra Ceia muck is a very poorly drained, nearly level, organic soil found in broad freshwater marsh areas. The soil was formed in thick deposits of hydrophytic plant remains. Black muck is found in the upper 8 inches, followed by dark reddish brown muck which extends to a depth of 65 inches or more. With the exception of extended dry periods, the soil is covered by water or the water table is within 10 inches of the surface for 6 to 12 months. Pahokee muck is a very poorly drained, nearly level, organic soil found in broad, freshwater marshes. The soils formed in moderately thick deposits of hydrophobic plant remains over limestone. The typical soil profile consists of black muck to a depth of about 36 inches followed by limestone bedrock to 51 inches. With the exception of extended dry periods, the soil is covered by water or the water table is within 10 inches of the surface for 6 to 12 months. Field Explorations SUBSURFACE CONDITIONS The field exploration consisted of drilling Standard Penetration Test (SPT) borings at two locations, both on Brown s Farm Road, one south of the existing culvert (TB-3) and one north of the culvert (TB-4). The original scope called for drilling Boring No. TB-3 on the canal side of the roadway guardrail. Upon approval by the District, this boring was moved to the roadway and deepened to account for the grade differential. The boring locations were marked on the pavement surface with white spray paint and were estimated using a hand held GPS unit. Locations of the borings are provided on the attached Figure 2. GPS coordinates (i.e. Latitude and Longitude) for the boring locations are shown in the following table. SPT Boring Latitude Longitude (TB) 3 N W ' 4 N ' W ' The boring locations were determined in the field by Dunkelberger. At each location the ground surface elevation was approximated from the topographical survey provided by Erdman Anthony. The ground surface elevations at the boring locations are shown on the attached Figure 2 and are referenced to NAVD. Since the borings were drilled in the roadway, we obtained a permit for the work through Palm Beach County (Permit No. RW ).

26 Project Culvert Replacements PC-03 Page 3 February 22, 2013 Standard Penetration Test Borings Subsurface conditions were explored using two (2) Standard Penetration Test (SPT) borings, drilled in accordance with ASTM D 1586 protocol. The borings were drilled by our SBE subconsultant, Radise International using a truck mounted Central Mine Equipment (CME) Model 75 drilling rig. Boring TB-3 was drilled to 35 feet below surface grade, while boring TB-4 was drilled to 50 feet below land surface. Samples of the subsurface materials were obtained continuously for the full depth of each boring. Groundwater levels were recorded for each SPT boring. The boreholes were sealed with neat cement grout in a bottom-to-top manner upon completion of each boring. The following is a photograph of the CME model 75 drilling rig. CME Model 75 drilling rig Stratigraphy Subsurface components found in the borings generally consisted of asphaltic concrete pavement over levee (roadway embankment) fill materials, which generally consisted of sand with trace shell fragments and gravel. The embankment materials were underlain by silty peat, and then a formation of silty, sandy limestone was found below the peat. One of the borings (TB-3) disclosed a thin layer of clayey sand within the upper portion of the limestone formation. The subsurface profiles for the SPT borings are provided on Figure 2. Detailed drilling logs are provided in Appendix A. The following table provides a description of the various strata found in the borings.

27 Project Culvert Replacements PC-03 Page 4 February 22, 2013 Table 1 - Stratigraphy Stratum No. Material Description Pavement 8 inches of Asphaltic Concrete and 6 inches of Base Course 1 Light gray-brown to dark gray-brown fine to medium SAND, trace silt, trace shell fragments, some clayey sand lenses, gravel, trace organic matter, some roots in upper 12 inches (SP, SP-SM) (LEVEE FILL) 3 Black silty PEAT (PT) 5 Gray clayey SAND with shell (SC) 8 Light gray to dark gray silty, sandy LIMESTONE, shell fragments, weakly to well cemented Note: Strata 2, 4, 6, 7 and 9 through 11 were not encountered in the borings associated with PC-03 and therefore are not included in this table. The Standard Penetration Test (SPT) is completed by dropping a 140-pound hammer for a vertical distance of 30 inches and summing the number of hammer blows required to drive a 2-inch diameter split barrel sampler a distance of 12 inches (the SPT after ASTM D 1586). The results of the SPT data were used to estimate the relative density of granular soils and the relative hardness of the limestone formation. The table that follows provides a description of each subsurface component, and the range and average SPT N-Values for each of the subsurface components. Table 2 Relative Density Stratum No. Material Description Range of SPT N-Values (blows/foot) Relative Density/ Consistency/ Hardness 1 SAND (LEVEE FILL) 11 to 55/10 Average 25 Medium Dense to Dense 3 Silty PEAT 3 to 4 Average 3 Soft 5 Clayey SAND 5 Loose 8 LIMESTONE Groundwater 5 to 50/3 Average 37 Weakly Cemented to Very Well Cemented Groundwater was measured in the borings on the dates that the borings were drilled (February 11, 2013). Based upon estimated ground surface elevations at each boring location, and the measured depths to groundwater, the groundwater elevations at the time of drilling were estimated to be and +9.8 feet NAVD for TB-3 and TB-4, respectively. The groundwater levels reported herein are indicative of the groundwater levels in the boreholes at the time of drilling. Water table levels on the site are expected to fluctuate in response to a variety of factors, including rainfall and surface water levels within the adjacent canal. LABORATORY TEST RESULTS Soil samples obtained from the borings were examined by a geotechnical engineer and classified in accordance with the Unified Soil Classification System (ASTM D 2487). Representative samples from the borings were tested for moisture content (ASTM D 2261), organic content (ASTM D 2974), and grain-size distribution (ASTM D 422). The test results are summarized in the following table.

28 Project Culvert Replacements PC-03 Page 5 February 22, 2013 Boring No. Depth (feet) Table 3 - Summary of Laboratory Test Results Moisture Organic Amount Passing Sieve Size (%) Stratum Content Content No. (%) (%) No. No. No. No. 1 3/ TB TB TB TB The moisture and organic content tests indicate that a peat layer has moisture contents in the range of 431 to 494 percent and corresponding organic contents of approximately 64 and 71 percent. The grain size distribution tests indicate that the embankment fill materials are reasonably well graded, and that the clayey sands of Stratum 5 contain approximately 19 percent passing the U.S. Standard No. 200 Sieve. No. 200 General Overview GEOTECHNICAL RECOMMENDATIONS The explorations for this study indicate the site of the proposed PC 03 culvert replacement project is generally underlain by a fairly thick asphalt pavement section over a layer of medium dense to dense granular fill followed by a layer of silty peat. The peat is followed by a formation of weakly cemented to very well-cemented limestone. A relatively thin layer of clayey sand with shell was found in the upper portions of the limestone in Boring TB-3. These subsurface profile conditions are considered to be favorable for the planned construction from a geotechnical engineering point-of-view. Materials found in the borings at the proposed culvert invert elevation consisted of moderately cemented to very wellcemented limestone. The proposed culverts may be supported on grade. Headwalls associated with the culvert may be supported on conventional spread footing foundations designed for a modest bearing capacity of 2,500 pounds per square foot (psf), or may consist of steel sheet piling. Excavations Unbraced excavations should be made in accordance with all applicable State and Federal requirements. More specifically, OSHA 29 CFR part 1926 (Subpart P, Excavations) defines the subsurface profile, within the planned depths of excavation, as Type C soil. The OSHA document states that Type C soils will remain stable when cut on a 1.5 horizontal to 1 vertical slope (1.5H:1V). However, borings drilled for this study indicate that subsoils will not be stable when cut in accordance with the minimum OSHA requirements. For these reasons, we recommend that temporary, fully dewatered excavation slopes be cut no steeper than 2H:1V. Where such excavation slopes cannot be established due to space restrictions, then steeper, braced (sheeted) side slopes will be required. Excavation bracing should be designed by an experienced structural engineer working in concert with the general contractor for the project.

29 Project Culvert Replacements PC-03 Page 6 February 22, 2013 Lateral Earth Pressure Design Criteria The following soil parameters should be utilized for estimation of lateral earth pressures in the design of earth retaining structures, including temporary steel sheet piling. Table 4 Lateral Earth Pressure Design Criteria - PC-03 Material Elevation γ moist γ sat Φ C K A K P Type (feet) (pcf) (pcf) (degrees) (psf) SAND +16 to PEAT +8 to LIMESTONE +2 to Notes: 1. Depth refers to below ground surface at boring locations. 2. γ moist, γ sat, Φ and C refer to moist unit weight, saturated unit weight, angle of internal friction, and cohesion, respectively. 3. K A and K P refer to the coefficients of active and passive lateral earth pressure, respectively. The value shown for K P is based upon ultimate, and should be factored for safety. 4. Hydrostatic and surcharge loads should be incorporated into the design as appropriate. Owing to the hardness of the limestone formation, we anticipate that sheet pile installation will require preforming through the rock if the required sheet pile tip elevations are within the rock. The values given for the limestone formation are in anticipation of an installation method that includes preforming (i.e. pre-augering) in order to facilitate installation of the sheeting into the well cemented formation of limestone. Dewatering Given a proposed culvert invert elevation of feet NAVD, dewatering will be necessary for in the dry construction of the culvert and associated earthwork. In order to prepare the base of the excavation, the dewatering should be capable of lowering the groundwater level to at least three feet below the bottom of the excavation at all times. The dewatering system should be designed by an experienced hydrogeologist under the employ of the general contractor. The proximity of the L15 Canal should be considered in the design of the dewatering system. Dewatering should be continued until the backfill is at least 3 feet above the water table elevation. Termination of the dewatering should be controlled such that the water table is allowed to rise at a rate equal to the total number of feet it was lowered divided by ten hours but not more than 1 foot/hour. Culverts The proposed 72-inch diameter CAP culverts may be constructed on grade. Ground preparation in advance of placement of the pipes should consist of normal excavation to the proposed structure bottom levels. Based upon an understanding of the proposed construction and the measured depth to groundwater, we expect that the bottom of the required excavation for the culvert will be below the ambient groundwater elevation. The in-situ materials directly beneath the culverts will likely consist of limestone. The materials do not require compaction. If soils are exposed at the culvert invert level, they should be compacted to at least 95% of the Modified Proctor maximum dry density to a depth of 12 inches.

30 Project Culvert Replacements PC-03 Page 7 February 22, 2013 In the event that the foundation soils are over excavated by more than 6 inches, a bedding material consisting of a coarse aggregate as specified in FDOT Section 901 for Aggregate Size Number 89, 8, 78, 68, 6 or 57 should be used to restore the excavation to proper grade. The gravel bedding material should be fully enveloped (wrapped) with an FDOT Type D-4 filter fabric, as specified in FDOT Standard Index No The coarse aggregate should not extend within 4 feet of the ends of the trench unless a cutoff such as a turn-down on the headwall foundation is used to cutoff seepage. Backfill and Compaction Backfill placed from the bottom of the excavation to pipe springlines should consist of sands having an SP or SP-SM classification in accordance with ASTM D 2487 (Unified Soil Classification System). Above the springlines, backfill adjacent to the new culverts should consist of sands or sand-gravel mixtures, having a maximum size of 1 inch, not more than 2 percent (by weight organic matter) and a maximum of 10 percent passing the U.S. Standard No. 200 Sieve. From the bottom of the excavation to 12 inches above the pipes, the backfill should be placed in horizontal lifts, evenly distributed on both sides of the pipes, not greater than 6 inches thick (loose measure), and each lift should be compacted to not less than 95 percent of the maximum dry density determined in accordance with Modified Proctor (ASTM D 1557). Above this, the backfill may be placed in horizontal lifts not exceeding 12 inches in loose thickness. Extra care should be exercised to obtain compaction beneath pipe haunches. Groundwater should be lowered and maintained at least 3 feet below the proposed structure bottom levels until the fill is has been placed and compacted at least 3 feet above the position of the normal water level. Headwalls The culvert headwalls may be supported on conventional shallow spread footing foundations, and be designed and proportioned for a net allowable soil bearing pressure of 2,500 psf, provided the headwall footings bottom below the silty peat soils. Foundation soil preparation should be completed as described in the section of this report related to the culvert. The walls should be carefully backfilled such that they are not subjected to lateral pressures that exceed those used in the design. Backfill within 3 feet of the wall should consist of sands with less than 10% passing the U.S. Standard No. 200 sieve. The backfill should be placed in loose lifts not exceeding 6 inches in thickness and should be uniformly compacted to at least 95% of the Modified Proctor maximum density. Only light, hand-operated equipment (weighing less than 1,000 pounds) should be used within 5 feet of the back of the walls to avoid developing excessive lateral earth pressures. Filter fabric should be placed over any wall joints, seams, drains or openings that will permit the passage of water in order to prevent the migration (piping) of the retained soils. Beyond the described 3-foot envelop, backfill should consist of sands or sand-gravel mixtures, having a maximum size of 1 inch, not more than 2 percent (by weight organic matter) and a maximum of 10 percent passing the U.S. Standard No. 200 Sieve. The backfill may be placed in loose lifts not exceeding 12 inches in thickness and should be uniformly compacted to at least 95% of the Modified Proctor maximum density.

31 Project Culvert Replacements PC-03 Page 8 February 22, 2013 Recommended parameters for design of the headwall are summarized in the following table. Condition of Wall Movement Table 5 Design Criteria for Headwall Backfill Friction Unit Weight (pcf) Angle, φ Submerged (degrees) Moist Soil Soil Earth Pressure Coefficient Restrained against rotation (at-rest) Wall rotates away from the retained soil at least 0.1% of the total wall height (active) Note: The above values reflect earth pressure due solely to the backfill specified herein. The design should also account for lateral pressure due to unbalanced hydrostatic forces and surcharge loads. The design parameters are based on the following assumptions: A permanent drainage system will be installed behind the wall that prevents development of hydrostatic pressure. Horizontal backfill. Sloping ground conditions on either side of the wall should be accounted for in the design. No surcharge loads will be applied. No safety factor is included. If the new headwall is designed without a drainage system, then additional forces from hydrostatic pressure induced behind the wall will need to be accounted for in the design. We recommend that these calculations assume that the backfill soils can become saturated up to the top of canal bank elevation. For analysis of sliding resistance of the base of the retaining wall, the ultimate coefficient of friction may be taken as 0.4 for the soils. The force which resists the sliding is calculated by multiplying the normal force on the base by the coefficient of friction. Full development of the frictional force could require displacement of the base of roughly 0.1 to 0.3 inch. Slope Restoration Areas of the canal banks that are disturbed during the construction process will need to be restored. We understand that the design of armoring of the slopes will be provided by the SFWMD. As a minimum, we have assumed that the canal banks will be returned to their original stable slope angle and the exposed bank soils will be protected through the use of rip rap, articulated concrete mats or other such means. (THIS SPACE INTENTIONALLY LEFT BLANK)

32 Project Culvert Replacements PC-03 Page 9 February 22, 2013 LIMITATIONS This culvert replacement study has been completed for the South Florida Water Management District (SFWMD). The reported data reflects conditions at the time the borings were drilled at the locations and depths indicated. It should be recognized that subsurface conditions may differ locally from those shown by borings. If differing conditions are found during construction, Dunkelberger should be notified immediately to determine if a change in recommendations is required. Dunkelberger warrants that the recommendations presented in this report are based upon recognized practices in the disciplines of soil mechanics, foundation engineering and engineering geology. No other warranties are expressed or implied. Discussions provided herein related to construction dewatering and excavation support are for the use of SFWMD for planning purposes only. Contractors bidding this job should align themselves with an experienced hydrogeologist and structural engineer for the design of the construction dewatering means and methods, and excavation bracing systems, respectively. Such work is beyond the scope of this work order. ooo We trust the information provided herein is sufficient for this phase of the project. Should you have any questions regarding the contents of this report, please call. Very truly yours, DUNKELBERGER ENGINEERING & TESTING, INC. Daniel J. Marieni, E.I. Staff Engineer Kevin E. Aubry, P.E. Geotechnical Services Manager FL Registration No Attachments: Figure 1 Vicinity Map Figure 2 Boring Location Plan and Subsurface Profiles Appendix A Detailed Drilling Logs

33

34

35 APPENDIX A DETAILED DRILLING LOGS

36 DUNKELBERGER ENGINEERING & TESTING, INC. TEST BORING LOG BORING NO. TB-3 Project: SFWMD Culverts PC03 Sheet No.: 1 of 1 Client: SFWMD Project No.: WPB Boring Location: See Boring Location Plan Casing Rock Core Elevation: Type: None None Boring Depth: 35 GPS Coordinates: Diam: None None Water Depth: N Depth: None None Drilled Date: 2/11/ W Drill Rig: CME 75 Driller: Tim F. Contractor: Radise Logged By: Akash Depth Blows On Sample N Sample Sample Munsell Material Description (ft) Spoon Per 6 Value No. Interval Color of asphalt followed by 6 of road-base YR 6/2 Fine to medium SAND, trace clay, gravel, shell fragments (SP, SP- SC) YR 6/2 Fine to medium SAND, trace clay, gravel, shell fragments (SP, SP- SC) YR 6/2 Fine to medium SAND, trace clay, gravel, shell fragments (SP, SP- SC) YR 5/2 Fine to medium SAND, trace silt, gravel, shell fragments (SP, SP-SM) YR 2/1 Silty PEAT (PT) YR 7/1 Silty, sandy LIMESTONE, shell fragments, moderately cemented YR 7/1 Fine to medium clayey SAND, shell fragments (SC) /3 50/ YR 7/1 Fine to medium clayey SAND, shell fragments (SC) YR 7/1 Silty LIMESTONE, shell fragments, moderately cemented YR 7/1 Silty LIMESTONE, shell fragments, moderately cemented YR 7/1 Silty, sandy LIMESTONE, shell fragments, moderately cemented /2 71/ YR 6/1 Silty, sandy LIMESTONE, shell fragments, well cemented YR 7/1 Silty, sandy LIMESTONE, shell fragments, well cemented YR 7/1 Silty, sandy LIMESTONE, shell fragments, moderately cemented YR 6/1 Silty, sandy LIMESTONE, shell fragments, moderately cemented YR 6/1 Silty, sandy LIMESTONE, shell fragments, moderately cemented YR 7/1 Sandy LIMESTONE, shell fragments, moderately cemented YR 6/1 Silty, sandy LIMESTONE, shell fragments, moderately cemented Boring Terminated at Borehole Grouted 0-36 DET 52 (Rev. 05/13/2008)

37 DUNKELBERGER ENGINEERING & TESTING, INC. TEST BORING LOG BORING NO. TB-4 Project: SFWMD Culverts PC03 Sheet No.: 1 of 2 Client: SFWMD Project No.: WPB Boring Location: See Boring Location Plan Casing Rock Core Elevation: Type: None None Boring Depth: 50 GPS coordinates: Diam: None None Water Depth: N Depth: None None Drilled Date: 2/1// W Drill Rig: CME 75 Driller: Tim F. Contractor: Radise Logged By: Akash Depth Blows On Sample N Sample Sample Munsell Material Description (ft) Spoon Per 6 Value No. Interval Color of asphalt followed by 6 of road-base YR 5/2 Clayey SAND, trace shell fragments, gravel, trace organic matter (SC) /4 55/ YR 5/2 Clayey SAND, trace shell fragments, gravel, trace organic matter (SC) YR 4/2 Fine sand, trace silt, gravel, trace shell fragments (SP, SP-SM) YR 2/1 Silty Peat (PT) YR 2/1 Silty Peat (PT) YR 2/1 Silty Peat (PT) YR 8/1 Silty LIMESTONE, trace shell fragments, moderately cemented YR 6/1 Silty, sandy LIMESTONE, trace shell fragments, moderately cemented YR 7/1 Silty, sandy LIMESTONE, shell fragments, moderately cemented YR 6/1 Silty, sandy LIMESTONE, shell fragments, moderately cemented YR 6/1 Silty, sandy LIMESTONE, shell fragments, moderately cemented /5 63/ YR 6/1 Silty, sandy LIMESTONE, shell fragments, well cemented /3 50/ YR 7/2 Silty, sandy LIMESTONE, shell fragments, well cemented YR 6/1 Silty LIMESTONE, shell fragments, moderately cemented YR 6/1 Sandy LIMESTONE, shell fragments, moderately cemented YR 6/1 Sandy LIMESTONE, shell fragments, moderately cemented YR 7/2 Silty, sandy LIMESTONE, trace shell fragments, weakly cemented YR 7/2 Silty, sandy LIMESTONE, trace shell fragments, weakly cemented YR 7/1 Silty, sandy LIMESTONE, shell fragments, moderately cemented YR 7/1 Silty LIMESTONE, trace shell fragments, well cemented (continued) DET 52 (Rev. 05/13/2008)

38 DUNKELBERGER ENGINEERING & TESTING, INC. TEST BORING LOG BORING NO. TB-4 Project: SFWMD Culverts PC03 Sheet No.: 2 of 2 Client: SFWMD Project No.: WPB Boring Location: See Boring Location Plan Casing Rock Core Elevation: Type: None None Boring Depth: 50 GPS Coordinates: Diam: None None Water Depth: N Depth: None None Drilled Date: 2/11/ W Drill Rig: CME 75 Driller: Tim F. Contractor: Radise Logged By: Akash Depth Blows On Sample N Sample Sample Munsell Material Description (ft) Spoon Per 6 Value No. Interval Color Silty LIMESTONE, trace shell fragments, moderately cemented Silty LIMESTONE, trace shell fragments, moderately cemented Silty LIMESTONE, shell fragments, moderately cemented Silty LIMESTONE, shell fragments, moderately cemented Silty LIMESTONE, shell fragments, moderately cemented Boring Terminated at Borehole Grouted DET 52 (Rev. 05/13/2008)

39 PC-05

40 Fort Lauderdale Port Saint Lucie Sarasota West Palm Beach South Florida Water Management District February 22, Gun Club Road Project No. WPB West Palm Beach, Florida BG 21.1 Attention: Subject: Ms. Sara Sciotto, P.E. Geotechnical Engineering Report Project Culvert Replacements PC-05 Contract No WO01 South Florida Water Management District Dear Ms. Sciotto: INTRODUCTION Pursuant to the requirements of Work Order WO 01, Dunkelberger Engineering & Testing, Inc. (Dunkelberger) has completed a program of subsurface exploration and geotechnical engineering related to Project Culvert PC-05, located along the northeast bank of the L12 Canal in Palm Beach County, Florida. This report presents a description of the methods of exploration, factual data obtained from the work and geotechnical engineering recommendations for design and construction of the culvert. PROJECT CONSIDERATIONS The project site consists of a levee that runs along the northeast bank of the L12 Canal. The subject area is located approximately 2.8 miles west of County Highway 880. The project vicinity map is provided on Figure 1. The site includes an existing culvert structure, which consists of four deteriorating 72 inch diameter Corrugated Metal Pipes. The following photograph depicts the North L12 Levee at the project location. North L12 Levee, Viewing Northwest State of Florida Board of Professional Engineers Authorization No Toll Free (877)

41 Project Culvert Replacements PC-05 Page 2 February 22, 2013 Based upon the Statement of Work, the South Florida Water Management District (SFWMD) plans to construct four new 72 inch Corrugated Aluminum Pipes (CAP s) and manually operated slide gates. The new culverts are to have an invert elevation of feet with respect to the North American Vertical Datum of 1988 (NAVD). SOIL SURVEY Information available from the U.S. Department of Agriculture Soil Conservation Service Soil Survey of Palm Beach County, Florida [1978] (SCS) depicts the project alignment to be predominantly mapped in Udorthents, Okeechobee muck, and Terra Ceia units. These map units are described below. Udorthents is an excessively drained, nearly level to steep, unconsolidated geologic material. The soil was formed in material that was excavated from the construction of canals and deposited along the banks in long narrow ridges. The surface layer is grayish brown sand and generally 8 inches thick. Below the surface layer is a layer consisting of large limestone boulders and some cobbles, extending to 80 inches. The water table is below 60 inches throughout the year. Okeechobee muck is a very poorly drained, nearly level, organic soil found in large freshwater marshes. The soil was formed in the remains of hydrophytic plants. The typical soil profile consists of black muck to a depth of 28 inches, followed by dark reddish brown mucky peat from 28 to 50 inches. Dark reddish brown muck is present from 50 to 66 inches. Under natural conditions, the soil is covered in water or the water table is within 10 inches of the surface at all times with the exception of extended dry periods. Terra Ceia muck is a very poorly drained, nearly level, organic soil found in broad freshwater marsh areas. The soil was formed in thick deposits of hydrophytic plant remains. Black muck is found in the upper 8 inches, followed by dark reddish brown muck which extends to a depth of 65 inches or more. With the exception of extended dry periods, the soil is covered by water or the water table is within 10 inches of the surface for 6 to 12 months. Field Explorations SUBSURFACE CONDITIONS The field exploration consisted of drilling Standard Penetration Test (SPT) borings at two locations, one on the levee slope northwest of the existing culvert (TB-5) and one near the levee crest southeast of the culvert (TB-6). The boring locations were situated in a secured area which required a gate key permit through the SFWMD. This work was accomplished through Permit No The boring locations were marked in the field with wooden stakes and were estimated using a hand held GPS unit. Locations of the borings are provided on the attached Figure 2. Detailed drilling logs are provided in Appendix A. GPS coordinates (i.e. Latitude and Longitude) for the boring locations are shown in the following table. SPT Boring Latitude Longitude (TB) 5 N W ' 6 N ' W '

42 Project Culvert Replacements PC-05 Page 3 February 22, 2013 The boring locations were determined in the field by Dunkelberger. At each location the ground surface elevation was approximated from the topographical survey provided by Erdman Anthony. The ground surface elevations at the boring locations are shown on the attached Figure 2 and are referenced to NAVD. Standard Penetration Test Borings Subsurface conditions were explored using two (2) Standard Penetration Test (SPT) borings, drilled in accordance with ASTM D 1586 protocol. A truck mounted Central Mine Equipment (CME) Model 45 drilling rig was utilized to access the boring locations and to drill the borings. Boring TB-5 was drilled to 30 feet below surface grade, while boring TB-6 was drilled to 50 feet below land surface. Samples of the subsurface materials were obtained continuously for the full depth of each boring. Groundwater levels were recorded for each SPT boring. The boreholes were sealed with neat cement grout in a bottom-to-top manner upon completion of each boring. The following is a photograph of the CME model 45 drilling rig.. CME Model 45 drilling rig Stratigraphy Subsurface components found in the borings generally consisted of levee fill materials (i.e. sand with trace shell fragments and gravel) over silty peat and then a thin layer of clayey sand. Sand with shell was found below the clayey sand, followed by silty, sandy limestone. The limestone formation was followed by slightly silty to silty sand and then sand with trace to slight amounts of silt. The following table provides a description of the various strata found in the borings.

43 Project Culvert Replacements PC-05 Page 4 February 22, 2013 Table 1 - Stratigraphy Stratum No. Material Description 1 Light gray-brown to dark gray-brown fine to medium SAND, trace silt, trace shell fragments, some clayey sand lenses, gravel, trace organic matter, some roots in upper 12 inches (SP, SP-SM) (LEVEE FILL) 3 Black silty PEAT (PT) 5 Gray clayey SAND, trace to some shell fragments (SC) 7 Light gray to gray fine to medium SAND, trace to some silt, shell fragments (SP, SP-SM) 8 Light gray to dark gray silty, sandy LIMESTONE, shell fragments, weakly to well cemented 10 Gray to dark gray SAND, slightly silty to silty, with shell fragments and gravel (SP-SM, SM) 11 Dark gray fine to medium SAND, trace to some shell fragments (SP, SP-SM) Note: Strata 2, 4, 6, and 9 were not encountered in the borings associated with PC-05 and therefore are not included in this table. The Standard Penetration Test (SPT) is completed by dropping a 140-pound hammer for a vertical distance of 30 inches and summing the number of hammer blows required to drive a 2-inch diameter split barrel sampler a distance of 12 inches (the SPT after ASTM D 1586). The results of the SPT data were used to estimate the relative density of granular soils and the relative hardness of the limestone formation. The table that follows provides a description of each subsurface component, and the range and average SPT N-Values for each of the subsurface components. Table 2 Relative Density Stratum No. Material Description 1 SAND (LEVEE FILL) 3 Silty PEAT 5 Clayey SAND 7 SAND 8 LIMESTONE 10 SAND with silt 11 SAND Range of SPT N-Values (blows/foot) 7 to 32 Average 15 3 to 9 Average 6 7 to 23 Average 15 8 to 83/8 Average to 50/1 Average to 11 Average to 22 Average 18 The subsurface profiles for the SPT borings are provided on Figure 2. Groundwater Relative Density/ Consistency/ Hardness Loose to Medium Dense Soft to Medium Stiff Loose to Medium Dense Medium Dense to Very Dense Very Well Cemented Loose to Medium Dense Medium Dense Groundwater was measured in the borings on the dates that the borings were drilled (January 18, 2013). Based upon estimated ground surface elevations at each boring location, and the measured depths to groundwater, the groundwater elevations at the time of drilling were estimated to be +6.9 and +8.6 feet NAVD for TB-5 and TB-6, respectively.

44 Project Culvert Replacements PC-05 Page 5 February 22, 2013 The groundwater levels reported herein are indicative of the groundwater levels in the boreholes at the time of drilling. Water table levels on the site are expected to fluctuate in response to a variety of factors, including rainfall and surface water levels within the adjacent canals. LABORATORY TEST RESULTS Soil samples obtained from the borings were examined by a geotechnical engineer and classified in accordance with the Unified Soil Classification System (ASTM D 2487). Representative samples from the borings were tested for moisture content (ASTM D 2261), organic content (ASTM D 2974), and grain-size distribution (ASTM D 422). The test results are summarized in the following table. Boring No. Depth (feet) Table 3 - Summary of Laboratory Test Results Moisture Organic Amount Passing Sieve Size (%) Stratum Content Content No. (%) (%) No. No. No. No. 1 3/4 3/ TB TB TB TB TB TB TB The moisture and organic content tests indicate that a peat layer had moisture contents in the range of 106 to 464 percent, with a corresponding organic content in the range of approximately 23 to 63 percent. The grain size distribution tests indicate that the sample from Stratum 5 has approximately 85 percent passing through the No. 4 Sieve and 24 percent passing through the No. 200 Sieve. A sample from Stratum 8 has a fines content (i.e. the amount passing through the US Standard No. 200 Sieve) of approximately 14 percent. No. 200 General Overview GEOTECHNICAL RECOMMENDATIONS The explorations for this study indicate the site of the proposed PC 05 culvert replacement project is generally underlain by a layer of loose to medium dense granular fill followed by a layer of peat. There is a thin layer of medium dense clayey sand below the peat followed by a medium dense to dense sand-shell mixture over a formation of very well cemented limestone. The limestone formation is underlain by medium dense sands. These subsurface profile conditions are considered to be favorable for the planned construction from a geotechnical engineering vantage point. Materials found in the borings at the proposed culvert invert elevation consisted of medium dense clayey sand. The proposed culvert may be supported on grade. Headwalls associated with the culvert may be supported on conventional spread footing foundations designed for a modest bearing capacity of 2,500 pounds per square foot (psf), or may consist of steel sheet piling.

45 Project Culvert Replacements PC-05 Page 6 February 22, 2013 Excavations Unbraced excavations should be made in accordance with all applicable State and Federal requirements. More specifically, OSHA 29 CFR part 1926 (Subpart P, Excavations) defines the subsurface profile, within the planned depths of excavation, as Type C soil. The OSHA document states that Type C soils will remain stable when cut on a 1.5 horizontal to 1 vertical slope (1.5H:1V). However, borings drilled for this study indicate that subsoils will not be stable when cut in accordance with the minimum OSHA requirements. For these reasons, we recommend that temporary, fully dewatered excavation slopes be cut no steeper than 2H:1V. Where such excavation slopes cannot be established due to space restrictions, then steeper, braced (sheeted) side slopes will be required. Excavation bracing should be designed by an experienced structural engineer working in concert with the general contractor for the project. Lateral Earth Pressure Design Criteria The following soil parameters should be utilized for estimation of lateral earth pressures in the design of earth retaining structures, including temporary steel sheet piling. Table 4 Lateral Earth Pressure Design Criteria - PC-05 Material Type Elevation γ moist γ sat Φ C K A K P (feet) (pcf) (pcf) (degrees) (psf) SAND +16 to PEAT +7 to Clayey SAND +1 to SAND -2 to LIMESTONE -7 to SAND -15 to SAND -21 to Notes: 1. Depth refers to below ground surface at boring locations. 2. γ moist, γ sat, Φ and C refer to moist unit weight, saturated unit weight, angle of internal friction, and cohesion, respectively. 3. K A and K P refer to the coefficients of active and passive lateral earth pressure, respectively. The value shown for K P is based upon ultimate, and should be factored for safety. 4. Hydrostatic and surcharge loads should be incorporated into the design as appropriate. Owing to the hardness of the limestone formation, we anticipate that sheet pile installation will require preforming through the rock if the required sheet pile tip elevations are within or below the bottom of the rock. The values given for the limestone formation are in anticipation of an installation method that includes preforming (i.e. pre-augering) in order to facilitate installation of the sheeting into the well cemented formation of limestone. Dewatering Given a proposed culvert invert elevation of feet NAVD, dewatering will be necessary for in the dry construction of the culvert and associated earthwork. In order to prepare the base of the excavation, the dewatering should be capable of lowering the groundwater level to at least three feet below the bottom of the excavation at all times. The dewatering system should be designed by an experienced hydrogeologist under the employ of the general contractor. The proximity of the L12 Canal should be considered in the design of the dewatering system. Dewatering should be continued until the backfill is at least 3 feet above

46 Project Culvert Replacements PC-05 Page 7 February 22, 2013 the water table elevation. Termination of the dewatering should be controlled such that the water table is allowed to rise at a rate equal to the total number of feet it was lowered divided by ten hours but not more than 1 foot/hour. Culverts The proposed 72-inch diameter CAP culverts may be constructed on grade. Ground preparation in advance of placement of the pipes should consist of normal excavation to the proposed structure bottom levels. Based upon an understanding of the proposed construction and the measured depth to groundwater, we expect that the bottom of the required excavation for the culvert will be below the ambient groundwater elevation. The in-situ soils directly beneath the culvert should be compacted to at least 95% of the Modified Proctor maximum dry density to a depth of 18 inches. Based on the results of the SPT borings, the in-situ soils at the proposed structure s foundation level are expected to be clayey sand and broken shell. In the event that the foundation soils are over excavated by more than 6 inches, a bedding material consisting of a coarse aggregate as specified in FDOT Section 901 for Aggregate Size Number 89, 8, 78, 68, 6 or 57 should be used to restore the excavation to proper grade. The gravel bedding material should be fully enveloped (wrapped) with an FDOT Type D-4 filter fabric, as specified in FDOT Standard Index No The coarse aggregate should not extend within 4 feet of the ends of the trench unless a cutoff such as a turn-down on the headwall foundation is used to cutoff seepage. Backfill and Compaction Backfill placed from the bottom of the excavation to pipe springlines should consist of sands having an SP or SP-SM classification in accordance with ASTM D 2487 (Unified Soil Classification System). Above the springlines, backfill adjacent to the new culverts should consist of sands or sand-gravel mixtures, having a maximum size of 1 inch, not more than 2 percent (by weight organic matter) and a maximum of 10 percent passing the U.S. Standard No. 200 Sieve. From the bottom of the excavation to 12 inches above the pipes, the backfill should be placed in horizontal lifts, evenly distributed on both sides of the pipes, not greater than 6 inches thick (loose measure), and each lift should be compacted to not less than 95 percent of the maximum dry density determined in accordance with Modified Proctor (ASTM D 1557). Above this, the backfill may be placed in horizontal lifts not exceeding 12 inches in loose thickness. Extra care should be exercised to obtain compaction beneath pipe haunches. Groundwater should be lowered and maintained at least 3 feet below the proposed structure bottom levels until the fill is has been placed and compacted at least 3 feet above the position of the normal water level. Headwalls The culvert headwalls may be supported on conventional shallow spread footing foundations, and be designed and proportioned for a net allowable soil bearing pressure of 2,500 psf. Foundation soil preparation should be completed as described in the section of this report related to the culvert.

47 Project Culvert Replacements PC-05 Page 8 February 22, 2013 The walls should be carefully backfilled such that they are not subjected to lateral pressures that exceed those used in the design. Backfill within 3 feet of the wall should consist of sands with less than 10% passing the U.S. Standard No. 200 sieve. The backfill should be placed in loose lifts not exceeding 6 inches in thickness and should be uniformly compacted to at least 95% of the Modified Proctor maximum density. Only light, hand-operated equipment (weighing less than 1,000 pounds) should be used within 5 feet of the back of the walls to avoid developing excessive lateral earth pressures. Filter fabric should be placed over any wall joints, seams, drains or openings that will permit the passage of water in order to prevent the migration (piping) of the retained soils. Beyond the described 3-foot envelop, backfill should consist of sands or sand-gravel mixtures, having a maximum size of 1 inch, not more than 2 percent (by weight organic matter) and a maximum of 10 percent passing the U.S. Standard No. 200 Sieve. The backfill may be placed in loose lifts not exceeding 12 inches in thickness and should be uniformly compacted to at least 95% of the Modified Proctor maximum density. Recommended parameters for design of the headwall are summarized in the following table. Condition of Wall Movement Table 5 Design Criteria for Headwall Backfill Friction Unit Weight (pcf) Angle, φ Submerged (degrees) Moist Soil Soil Earth Pressure Coefficient Restrained against rotation (at-rest) Wall rotates away from the retained soil at least 0.1% of the total wall height (active) Note: The above values reflect earth pressure due solely to the backfill specified herein. The design should also account for lateral pressure due to unbalanced hydrostatic forces and surcharge loads. The design parameters are based on the following assumptions: A permanent drainage system will be installed behind the wall that prevents development of hydrostatic pressure. Horizontal backfill. Sloping ground conditions on either side of the wall should be accounted for in the design. No surcharge loads will be applied. No safety factor is included. If the new headwall is designed without a drainage system, then additional forces from hydrostatic pressure induced behind the wall will need to be accounted for in the design. We recommend that these calculations assume that the backfill soils can become saturated up to the top of canal bank elevation. For analysis of sliding resistance of the base of the retaining wall, the ultimate coefficient of friction may be taken as 0.4 for the soils. The force which resists the sliding is calculated by multiplying the normal force on the base by the coefficient of friction. Full development of the frictional force could require displacement of the base of roughly 0.1 to 0.3 inch.

48 Project Culvert Replacements PC-05 Page 9 February 22, 2013 Slope Restoration Areas of the canal banks that are disturbed during the construction process will need to be restored. We understand that the design of armoring of the slopes will be provided by the SFWMD. As a minimum, we have assumed that the canal banks will be returned to their original stable slope angle and the exposed bank soils will be protected through the use of rip rap, articulated concrete mats or other such means. LIMITATIONS This culvert replacement study has been completed for the South Florida Water Management District (SFWMD). The reported data reflects conditions at the time the borings were drilled at the locations and depths indicated. It should be recognized that subsurface conditions may differ locally from those shown by borings. If differing conditions are found during construction, Dunkelberger should be notified immediately to determine if a change in recommendations is required. Dunkelberger warrants that the recommendations presented in this report are based upon recognized practices in the disciplines of soil mechanics, foundation engineering and engineering geology. No other warranties are expressed or implied. Discussions provided herein related to construction dewatering and excavation support are for the use of SFWMD for planning purposes only. Contractors bidding this job should align themselves with an experienced hydrogeologist and structural engineer for the design of the construction dewatering means and methods, and excavation bracing systems, respectively. Such work is beyond the scope of this work order. ooo We trust the information provided herein is sufficient for this phase of the project. Should you have any questions regarding the contents of this report, please call. Very truly yours, DUNKELBERGER ENGINEERING & TESTING, INC. Daniel J. Marieni, E.I. Staff Engineer Kevin E. Aubry, P.E. Geotechnical Services Manager FL Registration No Attachments: Figure 1 Vicinity Map Figure 2 Boring Location Plan and Subsurface Profiles Appendix A Detailed Drilling Logs

49

50

51 APPENDIX A DETAILED DRILLING LOGS

52 DUNKELBERGER ENGINEERING & TESTING, INC. TEST BORING LOG BORING NO. TB-5 Project: SFWMD Culverts PC05 Sheet No.: 1 of 1 Client: SFWMD Project No.: WPB Boring Location: See Boring Location Plan Casing Rock Core Elevation: Type: None None Boring Depth: 30 GPS coordinates: Diam: None None Water Depth: N Depth: None None Drilled Date: 1/18/ W Drill Rig: CME 45 Driller: BP, MQ, CN Contractor: Dunkelberger Logged By: DM Depth Blows On Sample N Sample Sample Munsell Material Description (ft) Spoon Per 6 Value No. Interval Color YR 6/1 Fine SAND, trace silt, rocks, trace roots, trace organic matter (SP, SP- SM) YR 7/1 Silty SAND, gravel, trace shell fragments (SM) YR 7/1 Fine SAND, trace silt, gravel, trace shell fragments (SP, SP-SM) YR 7/1 Fine SAND, trace silt, gravel, trace shell fragments (SP, SP-SM) YR 6/2 Fine to medium SAND, trace silt, clay nodules, trace gravel, trace shell fragments (SP, SP-SM) YR 5/2 Fine to medium SAND, trace silt, clay nodules, trace gravel, trace shell fragments (SP, SP-SM) YR 5/2 Fine to medium SAND, trace silt, clay nodules, trace gravel, trace shell fragments (SP, SP-SM) YR 2/2 Silty PEAT (PT) YR 2/2 Silty PEAT, trace shell fragments (PT) YR 2/2 Silty PEAT, trace shell fragments (PT) YR 6/1 Clayey SAND, shell fragments (SC) YR 6/1 Clayey SAND, shell fragments (SC) YR 6/1 Clayey SAND, shell fragments (SC) YR 6/1 Silty SAND, shell fragments (SM) YR 6/1 Silty SAND, shell fragments (SM) /4 70/ YR 7/1 Silty, sandy LIMESTONE, shell fragments, well cemented /3 50/ YR 6/2 Silty, sandy LIMESTONE, shell fragments, well cemented YR 7/1 Silty, sandy LIMESTONE, shell fragments, moderately cemented / YR 5/1 Silty, sandy LIMESTONE, shell fragments, well cemented /4 50/ YR 5/1 Silty, sandy LIMESTONE, shell fragments, well cemented YR 6/1 Silty SAND, shell fragments, gravel (SM) Boring Terminated at Borehole Grouted DET 52 (Rev. 05/13/2008)

53 DUNKELBERGER ENGINEERING & TESTING, INC. TEST BORING LOG BORING NO. TB-6 Project: SFWMD Culverts PC05 Sheet No.: 1 of 2 Client: SFWMD Project No.: WPB Boring Location: See Boring Location Map Casing Rock Core Elevation: Type: None None Boring Depth: 50 GPS coordinates: Diam: None None Water Depth: N Depth: None None Drilled Date: 1/18/ W Drill Rig: CME 45 Driller: BP, MQ, CN Contractor: Dunkelberger Logged By: DM Depth Blows On Sample N Sample Sample Munsell Material Description (ft) Spoon Per 6 Value No. Interval Color YR 4/2 Fine SAND, trace silt, gravel, trace roots, trace shell fragments, trace organic matter (SP, SP-SM) YR 7/2 Fine SAND, trace silt, gravel, trace shell fragments (SP, SP-SM) YR 5/2 Fine to medium SAND, clay nodules, gravel, trace shell fragments (SM) YR 5/2 Fine SAND, trace gravel, trace shell fragments (SP) YR 5/2 Fine to medium SAND, clay nodules, gravel, trace shell fragments (SP) YR 5/2 Fine to medium SAND, clay nodules, gravel, trace shell fragments (SP) YR 5/2 Fine to medium SAND, clay nodules, gravel, trace shell fragments (SP) YR 2/2 Silty PEAT (PT) YR 2/2 Silty PEAT (PT) YR 2/2 Silty PEAT (PT) YR 2/2 Silty PEAT (PT) YR 6/1 Clayey SAND, trace shell fragments (SC) YR 6/1 Clayey SAND, trace shell fragments (SC) YR 6/1 Silty SAND, shell fragments (SM) YR 5/2 Silty SAND, shell fragments (SM) YR 6/1 Fine SAND, gravel, trace shell fragments (SP) YR 6/1 Fine SAND, gravel, trace shell fragments (SP) /2 83/ YR 7/1 Clayey SAND, trace shell fragments (SC) YR 7/1 Silty SAND, shell fragments (SM) YR 7/1 Silty SAND, shell fragments (SM) /2 80/ YR 7/1 Silty, sandy LIMESTONE, shells, shell fragments, well cemented / YR 6/1 Silty, sandy LIMESTONE, shells, shell fragments, well cemented /2 50/ YR 5/1 Silty, sandy LIMESTONE, shells, shell fragments, well cemented /4 50/ YR 5/1 Silty, sandy LIMESTONE, shells, shell fragments, well cemented YR 4/2 Silty, sandy LIMESTONE, shells, shell fragments, well cemented 34 50/1 50/ YR 5/1 Fine to medium SAND, trace silt, gravel, trace shell fragments (SP, SP-SM) YR 5/1 Fine to medium SAND, trace silt, gravel, trace shell fragments (SP, SP-SM) YR 5/1 Fine to medium SAND, trace silt, gravel, trace shell fragments (SP, SP-SM) YR 5/2 Fine to medium SAND, trace shell fragments (SP, SP-SM) YR 5/1 Fine to medium SAND, trace shell fragments (SP, SP-SM) (continued) DET 52 (Rev. 05/13/2008)

54 DUNKELBERGER ENGINEERING & TESTING, INC. TEST BORING LOG BORING NO. TB-6 Project: SFWMD Culverts PC05 Sheet No.: 2 of 2 Client: SFWMD Project No.: WPB Boring Location: See Boring Location Plan Casing Rock Core Elevation: Type: None None Boring Depth: 50 GPS Coordinates: Diam: None None Water Depth: N Depth: None None Drilled Date: 1/18/ W Drill Rig: CME 45 Driller: BP, MQ, CN Contractor: Dunkelberger Logged By: DM Depth Blows On Sample N Sample Sample Munsell Material Description (ft) Spoon Per 6 Value No. Interval Color YR 4/1 Fine to medium SAND, trace silt, trace shell fragments (SP, SP-SM) YR 4/1 Fine to medium SAND, trace shell fragments (SP) YR 5/1 Fine to medium SAND, trace shell fragments (SP) YR 5/1 Fine to medium SAND, trace shell fragments (SP) YR 5/1 Fine to medium SAND, trace shell fragments (SP) Boring Terminated at Borehole Grouted DET 52 (Rev. 05/13/2008)

55 PC-06

56 Fort Lauderdale Port Saint Lucie Sarasota West Palm Beach South Florida Water Management District February 22, Gun Club Road Project No. WPB West Palm Beach, Florida BG 21.1 Attention: Subject: Ms. Sara Sciotto, P.E. Geotechnical Engineering Report Project Culvert Replacements PC-06 Contract No WO01 South Florida Water Management District Dear Ms. Sciotto: INTRODUCTION Pursuant to the requirements of Work Order WO 01, Dunkelberger Engineering & Testing, Inc. (Dunkelberger) has completed a program of subsurface exploration and geotechnical engineering related to Project Culvert PC-06, located along the north bank of the L12 Canal in Palm Beach County, Florida. This report presents a description of the methods of exploration, factual data obtained from the work and geotechnical engineering recommendations for design and construction of the culvert. PROJECT CONSIDERATIONS The project site consists of a levee that runs along the north bank of the L12 Canal. The subject area is located approximately 0.25 miles west of County Highway 880. The project vicinity map is provided on Figure 1. The site includes an existing culvert structure, which consists of five ailing 72 inch diameter Corrugated Metal Pipes. The following photograph depicts the North L12 Levee. North Side of North L12 Levee, Viewing West State of Florida Board of Professional Engineers Authorization No Toll Free (877)

57 Project Culvert Replacements PC-06 Page 2 February 22, 2013 Based upon the Statement of Work, the South Florida Water Management District (SFWMD) plans to construct five new 72 inch Corrugated Aluminum Pipes (CAP) and manually operated slide gates. The new culverts are to have an invert elevation of feet with respect to the North American Vertical Datum of 1988 (NAVD). SOIL SURVEY Information available from the U.S. Department of Agriculture Soil Conservation Service Soil Survey of Palm Beach County, Florida [1978] (SCS) depicts the project alignment to be predominantly mapped in Udorthents and Okeechobee muck units. These map units are described below. Udorthents is an excessively drained, nearly level to steep, unconsolidated geologic material. The soil was formed in material that was excavated from the construction of canals and deposited along the banks in long narrow ridges. The surface layer is grayish brown sand and generally 8 inches thick. Below the surface layer is a layer consisting of large limestone boulders and some cobbles, extending to 80 inches. The water table is below 60 inches throughout the year. Okeechobee muck is a very poorly drained, nearly level, organic soil found in large freshwater marshes. The soil was formed in the remains of hydrophytic plants. The typical soil profile consists of black muck to a depth of 28 inches, followed by dark reddish brown mucky peat from 28 to 50 inches. Dark reddish brown muck is present from 50 to 66 inches. Under natural conditions, the soil is covered in water or the water table is within 10 inches of the surface at all times with the exception of extended dry periods. Field Explorations SUBSURFACE CONDITIONS The field exploration consisted of drilling Standard Penetration Test (SPT) borings at two locations, one on the levee bench east of the existing culvert (TB-7) and one on the levee crest west of the culvert (TB-8). The boring locations were situated in a secured area which required a gate key permit through the SFWMD. This work was accomplished through Permit No The boring locations were marked in the field with wooden stakes and were estimated using a hand held GPS unit. Locations of the borings are provided on the attached Figure 2. Detailed drilling logs are provided in Appendix A. GPS coordinates (i.e. Latitude and Longitude) for the boring locations are shown in the following table. SPT Boring Latitude Longitude (TB) 7 N W ' 8 N ' W ' The boring locations were determined in the field by Dunkelberger. At each location the ground surface elevation was approximated from the topographical survey provided by Erdman Anthony. The ground surface elevations at the boring locations are shown on the attached Figure 2 and are referenced to NAVD.

58 Project Culvert Replacements PC-06 Page 3 February 22, 2013 Standard Penetration Test Borings Subsurface conditions were explored using two (2) Standard Penetration Test (SPT) borings, drilled in accordance with ASTM D 1586 protocol. A truck mounted Central Mine Equipment (CME) Model 45 drilling rig was utilized to access the boring locations and to drill the borings. Boring TB-7 was drilled to 30 feet below surface grade, while boring TB-8 was drilled to 50 feet below land surface. Samples of the subsurface materials were obtained continuously for the full depth of each boring. Groundwater levels were recorded for each SPT boring. The boreholes were sealed with neat cement grout in a bottom-to-top manner upon completion of each boring. A photograph of the CME model 45 drilling rig follows. Stratigraphy CME Model 45 drilling rig Subsurface components found in the borings generally consisted of levee fill materials (i.e. sand with trace shell fragments and gravel) over silty peat and then a thin layer of sandy clay (found only in TB-7). A layer of sand with shell was found below the sandy clay, followed by silty, sandy limestone. Slightly silty to silty sand was found below the limestone followed by sand with trace to slight amounts of silt. The subsurface profiles for the SPT and auger borings are provided on Figure 2. Descriptions of the various strata found in the borings are presented in the table that follows.

59 Project Culvert Replacements PC-06 Page 4 February 22, 2013 Table 1 - Stratigraphy Stratum No. Material Description 1 Light gray-brown to dark gray-brown fine to medium SAND, trace silt, trace shell fragments, some clayey sand lenses, gravel, trace organic matter, some roots in upper 12 inches (SP, SP-SM) (LEVEE FILL) 2 Brown SAND, trace silt (SP, SP-SM) 3 Black silty PEAT (PT) 6 Dark gray sandy CLAY (CL) 7 Light gray to gray fine to medium SAND, trace to some silt, shell fragments (SP, SP-SM) 8 Light gray to dark gray silty, sandy LIMESTONE, shell fragments, weakly to well cemented 10 Gray to dark gray SAND, slightly silty to silty, with shell fragments and gravel (SP-SM, SM) 11 Dark gray fine to medium SAND, trace to some shell fragments (SP, SP-SM) Note: Strata 4, 5, and 9 were not encountered in the borings associated with PC-06 and therefore are not included in this table. The Standard Penetration Test (SPT) is completed by dropping a 140-pound hammer for a vertical distance of 30 inches and summing the number of hammer blows required to drive a 2-inch diameter split barrel sampler a distance of 12 inches (the SPT after ASTM D 1586). The results of the SPT data were used to estimate the relative density of granular soils and the relative hardness of the limestone formation. The table that follows provides a description of each subsurface component, and the range and average SPT N-Values for each of the subsurface components. Table 2 Relative Density Stratum No. Material Description 1 SAND (LEVEE FILL) Range of SPT N-Values (blows/foot) 2 to 33 Average 14 Relative Density/ Consistency/ Hardness Very Loose to Dense 2 SAND 24 Medium Dense 3 Silty PEAT 2 to 4 Average 3 Soft 6 Sandy CLAY 3 Soft 7 SAND 5 to 14 Average 9 Loose to Medium Dense 8 LIMESTONE 35 to 50/2 Average 181 Very Well Cemented 10 SAND with silt 30 to 53 Average 42 Dense 11 SAND 6 to 30 Average 16 Loose to Medium Dense Groundwater Groundwater was measured in the borings on the dates that the borings were drilled (January 17, 2013). Based upon estimated ground surface elevations at each boring location, and the measured depths to groundwater, the groundwater elevations at the time of drilling were estimated to be +4.4 and +9.6 feet NAVD for TB-7 and TB-8, respectively.

60 Project Culvert Replacements PC-06 Page 5 February 22, 2013 The groundwater levels reported herein are indicative of the groundwater levels in the boreholes at the time of drilling. Water table levels on the site are expected to fluctuate in response to a variety of factors, including rainfall and surface water levels within the adjacent canals. LABORATORY TEST RESULTS Soil samples obtained from the borings were examined by a geotechnical engineer and classified in accordance with the Unified Soil Classification System (ASTM D 2487). Representative samples from the borings were tested for moisture content (ASTM D 2261), organic content (ASTM D 2974), and grain-size distribution (ASTM D 422). The test results are summarized in the following table. Boring No. Depth (feet) Table 3 - Summary of Laboratory Test Results Moisture Organic Amount Passing Sieve Size (%) Stratum Content Content No. (%) (%) No. No. No. No. 1/2 3/ TB TB TB TB TB TB The moisture and organic content tests indicate that a peat layer has moisture contents in the range of 313 to 543 percent, with corresponding organic contents of approximately 44 to 70 percent. The grain size distribution tests indicate that a sample from Stratum 6 has approximately 65 passing through the No. 200 Sieve. A sample from Stratum 7 has a fines content (i.e. the amount passing through the US Standard No. 200 Sieve) of approximately 12 percent and otherwise appears to be reasonably well graded. No. 200 General Overview GEOTECHNICAL RECOMMENDATIONS The explorations for this study indicate the site of the proposed PC 06 culvert replacement project is generally underlain by loose to medium dense granular fill soils over a layer of soft peat. One of the borings (TB-7) disclosed a relatively thin layer of sandy clay below the peat. Next in the profile is a layer of loose to medium dense sand-shell mixture and then a formation of very well cemented limestone. The borings terminate in sandy soils with variable amounts of soil fines and variable relative densities. These subsurface profile conditions are considered to be favorable for the planned construction from a geotechnical engineering stand point. Materials found in the borings at the proposed culvert invert elevation consisted of loose to medium dense sand and shell. The proposed culverts may be supported on grade. Headwalls associated with the culvert may be supported on conventional spread footing foundations designed for a modest bearing capacity of 2,500 pounds per square foot (psf), or may consist of steel sheet piling.

61 Project Culvert Replacements PC-06 Page 6 February 22, 2013 Excavations Unbraced excavations should be made in accordance with all applicable State and Federal requirements. More specifically, OSHA 29 CFR part 1926 (Subpart P, Excavations) defines the subsurface profile, within the planned depths of excavation, as Type C soils. The OSHA document states that Type C soils will remain stable when cut on a 1.5 horizontal to 1 vertical slope (1.5H:1V). However, borings drilled for this study indicate that subsoils will not be stable when cut in accordance with the minimum OSHA requirements. For these reasons, we recommend that temporary, fully dewatered excavation slopes be cut no steeper than 2H:1V. Where such excavation slopes cannot be established due to space restrictions, then steeper, braced (sheeted) side slopes will be required. Excavation bracing should be designed by an experienced structural engineer working in concert with the general contractor for the project. Lateral Earth Pressure Design Criteria The following soil parameters should be utilized for estimation of lateral earth pressures in the design of earth retaining structures, including temporary steel sheet piling. Table 4 Lateral Earth Pressure Design Criteria - PC-05 Material Elevation γ moist γ sat Φ C K A K P Type (feet) (pcf) (pcf) (degrees) (psf) SAND +18 to PEAT +7 to CLAY +2 to SAND 0 to LIMESTONE -9 to SAND -14 to SAND -19 to Notes: 1. Depth refers to below ground surface at boring locations. 2. γ moist, γ sat, Φ and C refer to moist unit weight, saturated unit weight, angle of internal friction, and cohesion, respectively. 3. K A and K P refer to the coefficients of active and passive lateral earth pressure, respectively. The value shown for K P is based upon ultimate, and should be factored for safety. 4. Hydrostatic and surcharge loads should be incorporated into the design as appropriate. Owing to the hardness of the limestone formation, we anticipate that sheet pile installation will require preforming through the rock if the required sheet pile tip elevations are within or below the bottom of the rock. The values given for the limestone formation are in anticipation of an installation method that includes preforming (i.e. pre-augering) in order to facilitate installation of the sheeting into the well cemented formation of limestone. Dewatering Given a proposed culvert invert elevation of feet NAVD, dewatering will be necessary for in the dry construction of the culvert and associated earthwork. In order to prepare the base of the excavation, the dewatering should be capable of lowering the groundwater level to at least three feet below the bottom of the excavation at all times. The dewatering system should be designed by an experienced hydrogeologist under the employ of the general contractor. The proximity of the L12 Canal should be considered in the design of the dewatering system. Dewatering should be continued until the backfill is at least 3 feet above

62 Project Culvert Replacements PC-06 Page 7 February 22, 2013 the water table elevation. Termination of the dewatering should be controlled such that the water table is allowed to rise at a rate equal to the total number of feet it was lowered divided by ten hours but not more than 1 foot/hour. Culverts The proposed 72-inch diameter CAP culverts may be constructed on grade. Ground preparation in advance of placement of the pipes should consist of normal excavation to the proposed structure bottom levels. Based upon an understanding of the proposed construction and the measured depth to groundwater, we expect that the bottom of the required excavation for the culvert will be below the ambient groundwater elevation. The in-situ soils directly beneath the culvert should be compacted to at least 95% of the Modified Proctor maximum dry density to a depth of 18 inches. Based on the results of the SPT borings, the in-situ soils at the proposed structure s foundation level are expected to be sandy clays and sand with broken shell. In the event that the foundation soils are over excavated by more than 6 inches, a bedding material consisting of a coarse aggregate as specified in FDOT Section 901 for Aggregate Size Number 89, 8, 78, 68, 6 or 57 should be used to restore the excavation to proper grade. The gravel bedding material should be fully enveloped (wrapped) with an FDOT Type D-4 filter fabric, as specified in FDOT Standard Index No The coarse aggregate should not extend within 4 feet of the ends of the trench unless a cutoff such as a turn-down on the headwall foundation is used to cutoff seepage. Backfill and Compaction Backfill placed from the bottom of the excavation to pipe springlines should consist of sands having an SP or SP-SM classification in accordance with ASTM D 2487 (Unified Soil Classification System). Above the springlines, backfill adjacent to the new culverts should consist of sands or sand-gravel mixtures, having a maximum size of 1 inch, not more than 2 percent (by weight organic matter) and a maximum of 10 percent passing the U.S. Standard No. 200 Sieve. From the bottom of the excavation to 12 inches above the pipes, the backfill should be placed in horizontal lifts, evenly distributed on both sides of the pipes, not greater than 6 inches thick (loose measure), and each lift should be compacted to not less than 95 percent of the maximum dry density determined in accordance with Modified Proctor (ASTM D 1557). Above this, the backfill may be placed in horizontal lifts not exceeding 12 inches in loose thickness. Extra care should be exercised to obtain compaction beneath pipe haunches. Groundwater should be lowered and maintained at least 3 feet below the proposed structure bottom levels until the fill is has been placed and compacted at least 3 feet above the position of the normal water level. Headwalls The culvert headwalls may be supported on conventional shallow spread footing foundations, and be designed and proportioned for a net allowable soil bearing pressure of 2,500 psf. Foundation soil preparation should be completed as described in the section of this report related to the culvert.

63 Project Culvert Replacements PC-06 Page 8 February 22, 2013 The walls should be carefully backfilled such that they are not subjected to lateral pressures that exceed those used in the design. Backfill within 3 feet of the wall should consist of sands with less than 10% passing the U.S. Standard No. 200 sieve. The backfill should be placed in loose lifts not exceeding 6 inches in thickness and should be uniformly compacted to at least 95% of the Modified Proctor maximum density. Only light, hand-operated equipment (weighing less than 1,000 pounds) should be used within 5 feet of the back of the walls to avoid developing excessive lateral earth pressures. Filter fabric should be placed over any wall joints, seams, drains or openings that will permit the passage of water in order to prevent the migration (piping) of the retained soils. Beyond the described 3-foot envelop, backfill should consist of sands or sand-gravel mixtures, having a maximum size of 1 inch, not more than 2 percent (by weight organic matter) and a maximum of 10 percent passing the U.S. Standard No. 200 Sieve. The backfill may be placed in loose lifts not exceeding 12 inches in thickness and should be uniformly compacted to at least 95% of the Modified Proctor maximum density. Recommended parameters for design of the headwall are summarized in the following table. Condition of Wall Movement Table 5 Design Criteria for Headwall Backfill Friction Unit Weight (pcf) Angle, φ Submerged (degrees) Moist Soil Soil Earth Pressure Coefficient Restrained against rotation (at-rest) Wall rotates away from the retained soil at least 0.1% of the total wall height (active) Note: The above values reflect earth pressure due solely to the backfill specified herein. The design should also account for lateral pressure due to unbalanced hydrostatic forces and surcharge loads. The design parameters are based on the following assumptions: A permanent drainage system will be installed behind the wall that prevents development of hydrostatic pressure. Horizontal backfill. Sloping ground conditions on either side of the wall should be accounted for in the design. No surcharge loads will be applied. No safety factor is included. If the new headwall is designed without a drainage system, then additional forces from hydrostatic pressure induced behind the wall will need to be accounted for in the design. We recommend that these calculations assume that the backfill soils can become saturated up to the top of canal bank elevation. For analysis of sliding resistance of the base of the retaining wall, the ultimate coefficient of friction may be taken as 0.4 for the soils. The force which resists the sliding is calculated by multiplying the normal force on the base by the coefficient of friction. Full development of the frictional force could require displacement of the base of roughly 0.1 to 0.3 inch.

64 Project Culvert Replacements PC-06 Page 9 February 22, 2013 Slope Restoration Areas of the canal banks that are disturbed during the construction process will need to be restored. We understand that the design of armoring of the slopes will be provided by the SFWMD. As a minimum, we have assumed that the canal banks will be returned to their original stable slope angle and the exposed bank soils will be protected through the use of rip rap, articulated concrete mats or other such means. LIMITATIONS This culvert replacement study has been completed for the South Florida Water Management District (SFWMD). The reported data reflects conditions at the time the borings were drilled at the locations and depths indicated. It should be recognized that subsurface conditions may differ locally from those shown by borings. If differing conditions are found during construction, Dunkelberger should be notified immediately to determine if a change in recommendations is required. Dunkelberger warrants that the recommendations presented in this report are based upon recognized practices in the disciplines of soil mechanics, foundation engineering and engineering geology. No other warranties are expressed or implied. Discussions provided herein related to construction dewatering and excavation support are for the use of SFWMD for planning purposes only. Contractors bidding this job should align themselves with an experienced hydrogeologist and structural engineer for the design of the construction dewatering means and methods, and excavation bracing systems, respectively. Such work is beyond the scope of this work order. ooo We trust the information provided herein is sufficient for this phase of the project. Should you have any questions regarding the contents of this report, please call. Very truly yours, DUNKELBERGER ENGINEERING & TESTING, INC. Daniel J. Marieni, E.I. Staff Engineer Kevin E. Aubry, P.E. Geotechnical Services Manager FL Registration No Attachments: Figure 1 Vicinity Map Figure 2 Boring Location Plan and Subsurface Profiles Appendix A Detailed Drilling Logs

65

66

67 APPENDIX A DETAILED DRILLING LOGS

68 DUNKELBERGER ENGINEERING & TESTING, INC. TEST BORING LOG BORING NO. TB-7 Project: SFWMD Culverts PC06 Sheet No.: 1 of 1 Client: SFWMD Project No.: WPB Boring Location: See Boring Location Plan Casing Rock Core Elevation: Type: None None Boring Depth: 30 GPS coordinates: Diam: None None Water Depth: N Depth: None None Drilled Date: 1/17/ W Drill Rig: CME 45 Driller: BP, MQ, CN Contractor: Dunkelberger Logged By: DM Depth Blows On Sample N Sample Sample Munsell Material Description (ft) Spoon Per 6 Value No. Interval Color YR 3/2 Fine to medium SAND, trace silt, roots, trace shell fragments, organic matter (SP, SP-SM) YR 5/3 Fine to medium SAND, clay nodules, shell fragments, trace gravel (SP) YR 4/2 Fine to medium SAND, roots, trace shell fragments, trace organic matter (SP) YR 4/1 Clayey SAND, shell fragments (SC) YR 5/1 Clayey SAND, trace shell fragments (SC) 6 WOH YR 2/2 Silty PEAT (PT) YR 2/2 Silty PEAT (PT) YR 2/2 Silty PEAT (PT) YR 3/1 Sandy CLAY (CL) YR 6/1 Fine to medium SAND, trace silt, trace gravel, shell fragments (SP, SP-SM) YR 6/1 Fine to medium SAND, trace silt, shell fragments (SP, SP-SM) YR 7/1 Silty SAND, shell fragments (SM) YR 6/1 Fine to medium SAND, trace silt, shell fragments (SP) * * YR 6/1 Fine to medium SAND, trace silt, shells fragments (SP) /3 50/ YR 5/1 Silty sandy LIMESTONE, shell fragments, well cemented /4 50/ YR 6/1 Silty sandy LIMESTONE, shell fragments, well cemented YR 7/1 Fine to medium SAND, trace silt, gravel, shell fragments (SP, SP-SM) YR 6/1 Fine to medium SAND, trace silt, gravel, shell fragments (SP, SP-SM) Boring Terminated at Borehole Grouted WOH weight of hammer * - No data. Depth interval was drilled through. DET 52 (Rev. 05/13/2008)

69 DUNKELBERGER ENGINEERING & TESTING, INC. TEST BORING LOG BORING NO. TB-8 Project: SFWMD Culverts PC06 Sheet No.: 1 of 2 Client: SFWMD Project No.: WPB Boring Location: See Boring Location Plan Casing Rock Core Elevation: Type: None None Boring Depth: 50 GPS Coordinates: Diam: None None Water Depth: N Depth: None None Drilled Date: 1/17/ W Drill Rig: CME 45 Driller: BP, MQ, CN Contractor: Dunkelberger Logged By: DM Depth Blows On Sample N Sample Sample Munsell Material Description (ft) Spoon Per 6 Value No. Interval Color YR 5/3 Fine SAND, trace gravel, trace shell fragments (SP) YR 5/2 Fine to medium SAND, clay nodules, shell fragments (SP) YR 5/2 Fine SAND, clay nodules, trace shell fragments, trace organic matter (SP) YR 5/2 Fine SAND, clay nodules, trace shell fragments, trace organic matter (SP) YR 6/2 Fine to medium SAND, gravel, shell fragments (SP) YR 6/2 Fine to medium SAND, gravel, shell fragments (SP) YR 5/1 Fine to medium SAND, trace shell fragments (SP) YR 3/1 Fine to medium SAND,, trace silt, shell fragments, organic matter (SP, SP-SM) YR 5/1 Clayey SAND, shell fragments (SC) YR 3/2 Silty PEAT (PT) WOH YR 3/2 Silty PEAT (PT) NO RECOVERY YR 4/1 Silty SAND, shell fragments (SM) YR 6/1 Silty SAND, trace clay, shell fragments (SM, SM-SC) YR 6/1 Silty SAND, shell fragments (SM) YR 6/1 Silty SAND, shell fragments (SM) YR 6/1 Silty SAND, shell fragments (SM) YR 5/2 Fine to medium SAND (SP) YR 5/2 Fine to medium SAND (SP) / YR 5/1 Silty sandy LIMESTONE, shell fragments, well cemented YR 3/1 Silty sandy LIMESTONE, shell fragments, well cemented 30 50/3 50/ YR 6/1 Fine SAND, trace silt, gravel, shell fragments (SP, SP-SM) YR 6/1 Fine SAND, trace silt, gravel, shell fragments (SP, SP-SM) YR 6/1 Fine SAND, trace silt, gravel, shell fragments (SP, SP-SM) / YR 6/1 Fine SAND, trace silt, gravel, shell fragments (SP, SP-SM) YR 6/1 Fine SAND, trace silt, gravel, shell fragments (SP, SP-SM) YR 5/1 Fine to medium SAND, trace silt, gravel, shell fragments (SP, SP-SM) YR 5/2 Fine to medium SAND, shell fragments (SP) YR 5/2 Fine to medium SAND, shell fragments (SP) WOH- weight of hammer. (continued) DET 52 (Rev. 05/13/2008)

70 DUNKELBERGER ENGINEERING & TESTING, INC. TEST BORING LOG BORING NO. TB-8 Project: SFWMD Culverts PC08 Sheet No.: 2 of 2 Client: SFWMD Project No.: WPB Boring Location: See Boring Location Plan Casing Rock Core Elevation: Type: None None Boring Depth: 50 GPS coordinates: Diam: None None Water Depth: N Depth: None None Drilled Date: 1/17/ W Drill Rig: CME 45 Driller: BP, MQ, CN Contractor: Dunkelberger Logged By: DM Depth Blows On Sample N Sample Sample Munsell Material Description (ft) Spoon Per 6 Value No. Interval Color YR 5/2 Fine to medium SAND, shell fragments (SP) YR 5/2 Fine to medium SAND, shell fragments (SP) /3 50/ YR 5/1 Silty sandy LIMESTONE, shell fragments, well cemented YR 6/2 Silty sandy LIMESTONE, shell fragments, well cemented 46 50/2 50/ YR 5/1 Fine to medium SAND, shell fragments (SP) YR 5/1 Fine to medium SAND, shell fragments (SP) YR 4/1 Fine to medium SAND, shell fragments (SP) Boring Terminated at Borehole Grouted DET 52 (Rev. 05/13/2008)

71 PC-18

72 Fort Lauderdale Port Saint Lucie Sarasota West Palm Beach South Florida Water Management District February 22, Gun Club Road Project No. WPB West Palm Beach, Florida BG 21.1 Attention: Subject: Ms. Sara Sciotto, P.E. Geotechnical Engineering Report Project Culvert Replacements PC-18 Contract No WO01 South Florida Water Management District Dear Ms. Sciotto: INTRODUCTION Pursuant to the requirements of Work Order WO 01, Dunkelberger Engineering & Testing, Inc. (Dunkelberger) has completed a program of subsurface exploration and geotechnical engineering related to Project Culvert PC-18, located along the north bank of the C18 Canal in Palm Beach County, Florida. This report presents a description of the methods of exploration, factual data obtained from the work and geotechnical engineering recommendations for design and construction of the culvert. PROJECT CONSIDERATIONS The project site consists of a levee that runs along the west bank of the C18 Canal. The subject area is located on the south side of the Wind in the Pines Subdivision, approximately 1 mile northeast of the Bee Line Highway (SR 710). The project vicinity map is provided on Figure 1. The site includes four existing 66-inch steel culvert structures. The pipes are significantly rusted and the gates no longer function. The following photograph depicts the North C18 Levee. C18 Canal Levee, North of Canal, Viewing East State of Florida Board of Professional Engineers Authorization No Toll Free (877)

73 Project Culvert Replacements PC-18 Page 2 February 22, 2013 Based upon the Statement of Work, the South Florida Water Management District (SFWMD) plans to construct four new 66 inch Corrugated Aluminum Pipes and a manually operated slide gates. The new culverts are to have an invert elevation of feet with respect to the North American Vertical Datum of 1988 (NAVD). SOIL SURVEY Information available from the U.S. Department of Agriculture Soil Conservation Service Soil Survey of Palm Beach County, Florida [1978] (SCS) depicts the project alignment to be predominantly mapped in Arents, very steep, Riviera sand, depressional, and Riviera sand units. These map units are described below. Arents, very steep, is an excessively drained, sandy soil found in long narrow ridges along the canals. The soil was formed in dominantly sandy material that was excavated from canals and deposited along the banks. Grayish brown sands are found in the upper 5 inches followed by light grayish brown sand from 5 to 28 inches. Below this layer, a very dark dray sand typically extends for 8 inches, followed by a pale brown sand from 36 to 50 inches. A mixture of pale brown sand with shell and limestone fragments extends from 50 to 80 inches. The water table is generally below a depth of 60 inches. Riviera sand, depressional is a poorly drained, nearly level soil found in shallow, well defined depressional areas. Fine sands are typically found in the upper 28 inches followed by sandy loam to a depth of 42 inches. Sand and shell fragments are found from 42 to 62 inches. Under natural conditions, the SCS reports that this unit covered with up to 2 feet of water for more than 6 months per year. Riviera sand is a poorly drained, nearly level soil found in broad, low areas. It has the similar pedon as described in the Riviera sand, depressional expect the sandy loam layer if found from 20 to 40 inches. The water table is within 10 inches of the surface for 2 to 4 months and within 10 to 30 inches for the remainder of the year. Field Explorations SUBSURFACE CONDITIONS The field exploration consisted of drilling Standard Penetration Test (SPT) borings at two locations, one on the levee bench east of the existing culvert (TB-9) and one on the levee crest west of the culvert (TB-10). The boring locations were situated in a secured area which required a gate key permit through the SFWMD. This work was accomplished through Permit No The boring locations were marked in the field with wooden stakes and were estimated using a hand held GPS unit. Locations of the borings are provided on the attached Figure 1. GPS coordinates (i.e. Latitude and Longitude) for the boring locations are shown in the following table. SPT Boring Latitude Longitude (TB) 9 N W ' 10 N W '

74 Project Culvert Replacements PC-18 Page 3 February 22, 2013 The boring locations were determined in the field by Dunkelberger. At each location the ground surface elevation was approximated from the topographical survey provided by Erdman Anthony. The ground surface elevations at the boring locations are shown on the attached Figure 2 and are referenced to NAVD. Standard Penetration Test Borings Subsurface conditions were explored using two (2) Standard Penetration Test (SPT) borings, drilled in accordance with ASTM D 1586 protocol. The borings were drilled by our SBE subconsultant, Radise International using a truck mounted Central Mine Equipment (CME) Model 75 drilling rig. Boring TB-9 was drilled on the levee slope to 30 feet below surface grade, while Boring TB-10 was drilled on the levee crest to 50 feet below land surface. Samples of the subsurface materials were obtained continuously for the full depth of each boring. Groundwater levels were recorded for each SPT boring. The boreholes were sealed with neat cement grout in a bottom-to-top manner upon completion of each boring. The following is a photograph of the CME model 75 drilling rig. Stratigraphy CME Model 75 drilling rig Subsurface components found in the borings generally consisted of levee fill materials (i.e. sand with trace shell fragments and gravel) over sand and then cemented sand and shell. Relatively clean to silty sand was found below the cemented sand and shell. The subsurface profiles for the SPT borings are provided on Figure 2. Detailed drilling logs are provided in Appendix A. The table that follows provides a description of the various strata found in the borings drilled for the PC-18 Culvert Replacement site.

75 Project Culvert Replacements PC-18 Page 4 February 22, 2013 Table 1 - Stratigraphy Stratum No. Material Description 1 Light gray-brown to dark gray-brown fine to medium SAND, trace silt, trace shell fragments, some clayey sand lenses, gravel, trace organic matter, some roots in upper 12 inches (SP, SP-SM) (LEVEE FILL) 2 Light brown to gray-brown fine to medium SAND, trace silt (SP, SP-SM) 7 Light gray to gray fine to medium SAND, trace to some silt, shell fragments (SP, SP-SM) 9 Gray cemented sand and shell, well cemented, grades weakly cemented with depth (COQUINA) 10 Gray to dark gray SAND, slightly silty to silty, with shell fragments and gravel (SP-SM, SM) Note: Strata 3, 4, 5, 6, 8, and 11 were not encountered in the borings associated with PC-18 and therefore are not included in this table. The Standard Penetration Test (SPT) is completed by dropping a 140-pound hammer for a vertical distance of 30 inches and summing the number of hammer blows required to drive a 2-inch diameter split barrel sampler a distance of 12 inches (the SPT after ASTM D 1586). The results of the SPT data were used to estimate the relative density of granular soils and the relative hardness of the limestone formation. The table that follows provides a description of each subsurface component, and the range and average SPT N-Values for each of the subsurface components. Table 2 Relative Density Stratum No. Material Description Range of SPT N-Values (blows/foot) Relative Density/ Consistency/ Hardness 1 SAND (LEVEE FILL) 2 to 16 Average 7 Very Loose to Medium Dense 2 SAND 3 to 13 Average 9 Very Loose to Medium Dense 7 SAND 10 to 15 Average 12 Medium Dense 9 COQUINA 8 to 50/4 Weakly Cemented to Average 52 Very Well Cemented 10 SAND with silt 43 Dense Groundwater Groundwater was measured in the borings on the dates that the borings were drilled (January 18, 2013). Based upon estimated ground surface elevations at each boring location, and the measured depths to groundwater, the groundwater elevations at the time of drilling were estimated to be and feet NAVD for TB-9 and TB-10, respectively. The groundwater levels reported herein are indicative of the groundwater levels in the boreholes at the time of drilling. Water table levels on the site are expected to fluctuate in response to a variety of factors, including rainfall and surface water levels within the adjacent canal.

76 Project Culvert Replacements PC-18 Page 5 February 22, 2013 LABORATORY TEST RESULTS Soil samples obtained from the borings were examined by a geotechnical engineer and classified in accordance with the Unified Soil Classification System (ASTM D 2487). Representative samples from the borings were tested for moisture content (ASTM D 2261), and grain-size distribution (ASTM D 422). The test results are summarized in the following table. Boring No. Depth (feet) Table 3 - Summary of Laboratory Test Results Moisture Amount Passing Sieve Size (%) Stratum Content No. No. No. No. No. (%) 1 3/4 3/ No. 200 TB General Overview GEOTECHNICAL RECOMMENDATIONS The explorations for this study indicate the site of the proposed PC 18 culvert replacement project is generally underlain by moderately thick deposits of loose to medium dense sands, and sand-shell mixtures over a formation of cemented sand and shell, which grades weakly cemented with depth. These subsurface profile conditions are considered to be favorable for the planned construction from a geotechnical engineering viewpoint. Materials found in the borings at the proposed culvert invert elevation consisted of loose to medium dense sands with trace silt. The proposed culvert may be supported on grade. Headwalls associated with the culvert may be supported on conventional spread footing foundations designed for a modest bearing capacity of 2,500 pounds per square foot (psf), or may consist of steel sheet piling. Excavations Unbraced excavations should be made in accordance with all applicable State and Federal requirements. More specifically, OSHA 29 CFR part 1926 (Subpart P, Excavations) defines the subsurface profile, within the planned depths of excavation, as a sand (Type C soil). The OSHA document states that Type C soils will remain stable when cut on a 1.5 horizontal to 1 vertical slope (1.5H:1V). However, borings drilled for this study indicate that subsoils will not be stable when cut in accordance with the minimum OSHA requirements. For these reasons, we recommend that temporary, fully dewatered excavation slopes be cut no steeper than 2H:1V. Where such excavation slopes cannot be established due to space restrictions, then steeper, braced (sheeted) side slopes will be required. Excavation bracing should be designed by an experienced structural engineer working in concert with the general contractor for the project. (THIS SPACE INTENTIONALLY LEFT BLANK)

77 Project Culvert Replacements PC-18 Page 6 February 22, 2013 Lateral Earth Pressure Design Criteria The following table provides soil parameters that should be utilized for estimation of lateral earth pressures in the design of earth retaining structures, including temporary steel sheet piling. Table 4 Lateral Earth Pressure Design Criteria - PC-01 Material Elevation γ moist γ sat Φ C K A K P Type (feet) (pcf) (pcf) (degrees) (psf) SAND +24 to COQUINA -5 to Notes: 1. Depth refers to below ground surface at boring locations. 2. γ moist, γ sat, Φ and C refer to moist unit weight, saturated unit weight, angle of internal friction, and cohesion, respectively. 3. K A and K P refer to the coefficients of active and passive lateral earth pressure, respectively. The value shown for K P is based upon ultimate, and should be factored for safety. 4. Hydrostatic and surcharge loads should be incorporated into the design as appropriate. Owing to the hardness of the cemented sand and shell formation, we anticipate that sheet pile installation will require preforming through the rock if the required sheet pile tip elevations are within or below the bottom of the rock. The values given for the cemented sand and shell formation are in anticipation of an installation method that includes preforming (i.e. preaugering) in order to facilitate installation of the sheeting into the well cemented formation of sand and shell. Dewatering Given a proposed culvert invert elevation of feet NAVD, dewatering will be necessary for in the dry construction of the culverts and associated earthwork. In order to prepare the base of the excavation, the dewatering should be capable of lowering the groundwater level to at least three feet below the bottom of the excavation at all times. The dewatering system should be designed by an experienced hydrogeologist under the employ of the general contractor. The proximity of the C18 Canal should be considered in the design of the dewatering system. Dewatering should be continued until the backfill is at least 3 feet above the water table elevation. Termination of the dewatering should be controlled such that the water table is allowed to rise at a rate equal to the total number of feet it was lowered divided by ten hours but not more than 1 foot/hour. Culverts The proposed 66-inch diameter corrugated aluminum culverts may be constructed on grade. Ground preparation in advance of construction of the culverts should consist of normal excavation to the proposed structure bottom levels. Based upon an understanding of the proposed construction and the measured depth to groundwater, we expect that the bottom of the required excavation for the culverts will be below the ambient groundwater elevation. The in-situ soils directly beneath the culvert should be compacted to at least 95% of the Modified Proctor maximum dry density to a depth of 18 inches.

78 Project Culvert Replacements PC-18 Page 7 February 22, 2013 Based on the results of the SPT borings, the in-situ soils at the proposed structure s foundation level are expected to be sand with trace to slight amounts of silt. In the event that the foundation soils are over excavated by more than 6 inches, a bedding material consisting of a coarse aggregate as specified in FDOT Section 901 for Aggregate Size Number 89, 8, 78, 68, 6 or 57 should be used to restore the excavation to proper grade. The gravel bedding material should be fully enveloped (wrapped) with an FDOT Type D-4 filter fabric, as specified in FDOT Standard Index No The coarse aggregate should not extend within 4 feet of the ends of the trench unless a cutoff such as a turn-down on the headwall foundation is used to cutoff seepage. Backfill and Compaction Backfill placed from the bottom of the excavation to pipe springlines should consist of sands having an SP or SP-SM classification in accordance with ASTM D 2487 (Unified Soil Classification System). Above the springlines, backfill adjacent to the new culverts should consist of sands or sand-gravel mixtures, having a maximum size of 1 inch, not more than 2 percent (by weight organic matter) and a maximum of 10 percent passing the U.S. Standard No. 200 Sieve. From the bottom of the excavation to 12 inches above the pipes, the backfill should be placed in horizontal lifts, evenly distributed on both sides of the pipes, not greater than 6 inches thick (loose measure), and each lift should be compacted to not less than 95 percent of the maximum dry density determined in accordance with Modified Proctor (ASTM D 1557). Above this, the backfill may be placed in horizontal lifts not exceeding 12 inches in loose thickness. Extra care should be exercised to obtain compaction beneath pipe haunches. Groundwater should be lowered and maintained at least 3 feet below the proposed structure bottom levels until the fill is has been placed and compacted at least 3 feet above the position of the normal water level. Headwalls The culvert headwalls may be supported on conventional shallow spread footing foundations, and be designed and proportioned for a net allowable soil bearing pressure of 2,500 psf. Foundation soil preparation should be completed as described in the section of this report related to the culverts. The walls should be carefully backfilled such that they are not subjected to lateral pressures that exceed those used in the design. Backfill within 3 feet of the wall should consist of sands with less than 10% passing the U.S. Standard No. 200 sieve. The backfill should be placed in loose lifts not exceeding 6 inches in thickness and should be uniformly compacted to at least 95% of the Modified Proctor maximum density. Only light, hand-operated equipment (weighing less than 1,000 pounds) should be used within 5 feet of the back of the walls to avoid developing excessive lateral earth pressures. Filter fabric should be placed over any wall joints, seams, drains or openings that will permit the passage of water in order to prevent the migration (piping) of the retained soils. Beyond the described 3-foot envelop, backfill should consist of sands or sand-gravel mixtures, having a maximum size of 1 inch, not more than 2 percent (by weight organic matter) and a maximum of 10 percent passing the U.S. Standard No. 200 Sieve. The backfill may be placed in loose lifts not exceeding 12 inches in thickness and should be uniformly compacted to at least 95% of the Modified Proctor maximum density.

79 Project Culvert Replacements PC-18 Page 8 February 22, 2013 Recommended parameters for design of the headwall are summarized in the following table. Condition of Wall Movement Table 5 Design Criteria for Headwall Backfill Friction Unit Weight (pcf) Angle, φ Submerged (degrees) Moist Soil Soil Earth Pressure Coefficient Restrained against rotation (at-rest) Wall rotates away from the retained soil at least 0.1% of the total wall height (active) Note: The above values reflect earth pressure due solely to the backfill specified herein. The design should also account for lateral pressure due to unbalanced hydrostatic forces and surcharge loads. The design parameters are based on the following assumptions: A permanent drainage system will be installed behind the wall that prevents development of hydrostatic pressure. Horizontal backfill. Sloping ground conditions on either side of the wall should be accounted for in the design. No surcharge loads will be applied. No safety factor is included. If the new headwall is designed without a drainage system, then additional forces from hydrostatic pressure induced behind the wall will need to be accounted for in the design. We recommend that these calculations assume that the backfill soils can become saturated up to the top of canal bank elevation. For analysis of sliding resistance of the base of the retaining wall, the ultimate coefficient of friction may be taken as 0.4 for the soils. The force which resists the sliding is calculated by multiplying the normal force on the base by the coefficient of friction. Full development of the frictional force could require displacement of the base of roughly 0.1 to 0.3 inch. Slope Restoration Areas of the canal banks that are disturbed during the construction process will need to be restored. We understand that the design of armoring of the slopes will be provided by the SFWMD. As a minimum, we have assumed that the canal banks will be returned to their original stable slope angle and the exposed bank soils will be protected through the use of rip rap, articulated concrete mats or other such means. (THIS SPACE INTENTIONALLY LEFT BLANK)

80 Project Culvert Replacements PC-18 Page 9 February 22, 2013 LIMITATIONS This culvert replacement study has been completed for the South Florida Water Management District (SFWMD). The reported data reflects conditions at the time the borings were drilled at the locations and depths indicated. It should be recognized that subsurface conditions may differ locally from those shown by borings. If differing conditions are found during construction, Dunkelberger should be notified immediately to determine if a change in recommendations is required. Dunkelberger warrants that the recommendations presented in this report are based upon recognized practices in the disciplines of soil mechanics, foundation engineering and engineering geology. No other warranties are expressed or implied. Discussions provided herein related to construction dewatering and excavation support are for the use of SFWMD for planning purposes only. Contractors bidding this job should align themselves with an experienced hydrogeologist and structural engineer for the design of the construction dewatering means and methods, and excavation bracing systems, respectively. Such work is beyond the scope of this work order. ooo We trust the information provided herein is sufficient for this phase of the project. Should you have any questions regarding the contents of this report, please call. Very truly yours, DUNKELBERGER ENGINEERING & TESTING, INC. Daniel J. Marieni, E.I. Staff Engineer Kevin E. Aubry, P.E. Geotechnical Services Manager FL Registration No Attachments: Figure 1 Vicinity Map Figure 2 Boring Location Plan and Subsurface Profiles Appendix A Detailed Drilling Logs

81

82