03_00_90_05_Geotechnical_Report_QuadrantsReport_3and4.pdf

Department Of The Army New York District Corps of Engineers Jacob K. Javits Federal Building 26 Federal Plaza New York, NY 10278-0090

Contract #W912DS-12-D-0002,Task Order #0015 Geophysical and Geotechnical investigation: Outfall design at Loch Arbour to Elberon, NJ under the Sandy Hook to Barnegat Beach Erosion Control Project

Quadrants 3 and 4 July 31, 2014

27 GLEN ROAD, NORTH ENTRANCE

SANDY HOOK, CONNECTICUT 06482

P.O. BOX 178, NEWTOWN, CT 06470

(203) 270-8100, FAX (203) 364-0480

www.e4sciences.com i

All interpretations are opinions based on inferences from sonar or other measurements.

We cannot, and do not, guarantee the accuracy or correctness of any interpretation. We shall not, except in the case of gross or willful negligence on our part, be liable or responsible for any loss, costs, damages or expenses incurred or sustained by anyone resulting from any interpretations made by any of our officers, agents or employees.

5.3 Quadrant Report 3. Outfalls from 36B to 29

This report focuses on the southernmost quadrant from outfalls 36B to 29.

Figure 5.3-1 plots the orthosonographs insonified from east and west for outfalls 36B to 29.

Figure 5.3-2 plots the bathymetric map and Top-of-Tertiary map for outfalls 36B to 29. Figure 5.3-3 plots the isopach map of Quaternary sand for outfalls 36B to 29. Figure 5.3-4 plots the seismic cross section perpendicular to the shore in the vicinity of outfalls 36B to 29. Figure 5.3-5 plots the geological cross section perpendicular to the shore in the vicinity of outfalls 36B to 29.

Table 5.3-1 shows the target list for the southernmost quadrant from outfalls 36B to 29. Targets 2, 3, and 4 are identified in Figures III-1 to III-3. Plate 10 also shows these targets. Figures III-12 to III-14 shows detailed images of targets 2 and 3.

Table 5.3-1. Target list for outfalls 36B to 29.

Target number Area of Target Easting NJSP-ft

Northing NJSP-ft

Target description

2 36B-Y 635,205.3 518,316.8 Remnant outfall 636,724.5 518,371.2 636,722.9 517,660.9 635,205.3 518,252.1

3 North 36B 635,301.2 518,798.0 sewer pipes 635,801.8 518,643.3 635,777.7 518,565.3 635,277.1 518,720.0

4 Between 28 and 29

635,966.9 521,821.5 Overturned barge 636,013.5 521,821.5 636,013.5 521,765.5 635,966.9 521,765.5

Figure 5.3-1. Orthosonograph insonifed from east and west from Outfalls 36B to 26.

Figure 5.3-2. (Left) Bathymetric and topographic map with 5ft contours. (Right) Top of Tertiary map from Outfalls 36B to 26.

Figure 5.3-3. Isopach map of Quaternary sands from Outfalls 36B to 26.

Figure 5.3-4. Seismic section perpendicular to the shore. Near Outfall 34.

Figure 5.3-5. Geologic cross section perpendicular to the shore. Near Outfall 34.

5.3.1 Outfall 36B

The next set focuses just on Outfall 36B. Figure 5.3-6 plots the detailed orthosonograph in the vicinity of Outfall 36B. Figure 5.3-7 shows the oblique aerial photographs of Outfall 36B. Figure 5.3-8 shows existing conditions for Outfall 36B. Figure 5.3-9 shows more existing conditions for Outfall 36B. Figure 5.3-10 shows more existing conditions for Outfall 36B. Figure 5.3-11 plots 3D imaging of Outfall 36B.

Figure 5.3-12 plots 3D imaging of a remnant outfall offshore of Outfall 36B. Figure 5.3-13 plots the seismic cross section through the remnant outfall. Figure 5.3-14 plots the seismic section through the sewer outfall slightly to the north of Outfall 36B.

Figure 5.3-6. Detailed orthosonograph of Outfall 36B.

Figure 5.3-7. Aerial photographs of Outfall 36B.

Figure 5.3-8. Existing conditions of Outfall 36B.

Figure 5.3-9. Existing conditions of Outfall 36B.

Figure 5.3-10. Existing conditions of Outfall 36B.

Figure 5.3-11. 3D imaging of Outfall 36B.

Figure 5.3-12. 3D imaging of sewer outfall just south of Outfall 36B.

Figure 5.3-13. Seismic cross section perpendicular to the shore showing the pipe on Figure 5.3-12. The unique data representation (UDR) is in green. These unique identifiers show the signal of the remnant pipe.

Figure 5.3-14. Seismic cross sections showing the outfall pipe. The unique data representation (UDR) is in green. These unique identifiers show the signal of the sewer outfall.

5.3.2 Outfalls 34, 33, 32, New Outfall #4, and New Outfall #3

Figure 5.3-15 plots the detailed orthosonograph vicinity of Outfall 34, 33 and 32. Figure 5.3-16 shows the oblique aerial photographs of Outfall 34, 33, 32, New Outfall #4, and New Outfall #3.

Figure 5.3-17 shows existing conditions for Outfall 34. Figure 5.3-18 shows more existing conditions for Outfall 34. Figure 5.3-19 shows more existing conditions for Outfall 34. Figure 5.3-20 shows more existing conditions for Outfall 33 and 32. Figure 5.3-21 shows more existing conditions for Outfall 333 and 32. Figure 5.3-22 shows aerial photographs for New Outfall #4 and New Outfall #3. Figure 5.3-23 shows existing conditions for New Outfall #4 and New Outfall #3. Figure 5.3-24 shows more existing conditions for New Outfall #4 and New Outfall #3. Figure 5.3-25 plots 3D imaging of Outfall 34, 33, and 32.

Figure 5.3-15. Detailed orthosonograph insonifed from east and west from Outfalls 34, 33, and 32.

Figure 5.3-16. Aerial photographs of Outfalls 34, 33, 32, New Outfall #4, and New Outfall #3.

Figure 5.3-17. Existing conditions of Outfall 34.

Figure 5.3-18. Existing conditions of Outfall 34.

Figure 5.3-19. Existing conditions of Outfall 34.

Figure 5.3-20. Existing conditions of Outfalls 33 and 32.

Figure 5.3-21. Existing conditions of Outfalls 33 and 32.

Figure 5.3-22. Aerial photographs of New Outfall #4 and New Outfall #3.

Figure 5.3-23. Existing conditions New Outfall #4 with New Outfall #3 in the background.

Figure 5.3-24. Existing condition of New Outfall #3.

Figure 5.3-25. 3D imaging of Outfall 34, 33, 32

5.3.3 Outfall 29

Figure 5.3-26 plots the detailed orthosonograph vicinity of Outfall 29. Figure 5.3-27 shows the oblique aerial photographs of Outfall 29. Figure 5.3-28 shows existing conditions for Outfall 29.

Figure 5.3-29 shows more existing conditions for Outfall 29. Figure 5.3-30 shows more existing conditions for Outfall 29. Figure 5.3-31 plots 3D imaging of Outfall 29.

Figure 5.3-26. Detailed orthosonograph insonifed from east and west from Outfall 29.

Figure 5.3-27. Aerial photographs for Outfall 29, Garfield Avenue.

Figure 5.3-28. Existing conditions for Outfall 29, Garfield Avenue.

Figure 5.3-29. Existing conditions for Outfall 29, Garfield Avenue.

Figure 5.3-30. Existing conditions for Outfall 29, Garfield Avenue.

Figure 5.3-31. 3D imaging of Outfall 29.

5.4 Quadrant Report 4. Outfalls from 28 to 19

This report focuses on the southernmost quadrant from outfalls 28 to 19.

Figure 5.4-1 plots the orthosonographs insonified from east and west for outfalls 28 to 19. Figure 5.4-2 plots the bathymetric map and Top-of-Tertiary map for outfalls 28 to 19. Figure 5.4-3 plots the isopach map of Quaternary sand for outfalls 28 to 19. Figure 5.4-4 plots the seismic cross section perpendicular to the shore in the vicinity of outfalls 28 to 19. Figure 5.4-5 plots the geological cross section perpendicular to the shore in the vicinity of outfalls 28 to 19.

Table 5.4-1 shows the target list for the southernmost quadrant from outfalls 28 to 19. Targets 5 and 6 are identified in Figures IV-1 to IV-3. Plate 12 also shows these targets.

Table 5.4-1. Target list for outfalls 28 to 19.

Target number Area of Target Easting NJSP-ft

Northing NJSP-ft

Target description

5 Outfall 19 636,670.8 525,782.4 Outcrop 636,825.6 525,782.4 636,825.6 525,643.5 636,670.8 525,643.5

6 Ship wreck 636,927.2 526,758.1 170ft-diameter 636,670.8 525,782.4 636,825.6 525,782.4 636,825.6 525,643.5

Figure 5.4-1. Orthosonograph insonifed from east and west from Outfalls 28 to 19.

Figure 5.4-2. (Left) Bathymetric and topographic map with 5ft contours. (Right) Top of Tertiary map from Outfalls 28 to 19.

Figure 5.4-3. Isopach map of Quaternary sands from Outfalls 28 to 19.

Figure 5.4-4. Seismic cross section perpendicular to the shore. Near Outfall 19.

Figure 5.4-5. Geologic cross section perpendicular to the shore. Near Outfall 19.

5.4.1 Outfall 28

The next set focuses just on Outfall 28. Figure 5.4-6 plots the detailed orthosonograph in vicinity of Outfall 28. Figure 5.4-7 shows the oblique aerial photographs of Outfall 28. Figure 5.4-8 shows existing conditions for Outfall 28. Figure 5.4-9 shows existing conditions for Outfall 28.

Figure 5.4-10 shows access point for Outfall 28. Figure 5.3-11 plots 3D imaging of Outfall 28.

Figure 5.4-6. Detailed orthosonograph of Outfall 28.

Figure 5.4-7. Aerial photographs for Outfall 28, Breakwater Beach Club.

Figure 5.4-8. Existing conditions for Outfall 28, Breakwater Beach Club.

Figure 5.4-9. Existing conditions for Outfall 28, Breakwater Beach Club.

Figure 5.4-10. Beach access, Breakwater Beach Club.

Figure 5.4-11. 3D imaging of Outfall 29 and 28.

5.4.2 New Outfall #2 and New Outfall #1

Figure 5.4-12 plots the detailed orthosonograph vicinity of New Outfall #2 and New Outfall #1.

Figure 5.4-13 shows the oblique aerial photographs of New Outfall #2 and New Outfall #1.

Figure 5.4-14 shows existing conditions for Outfall 34. Figure 5.4-15 shows more existing conditions for New Outfall #2 and New Outfall #1. Figure 5.4-16 shows aerial photographs for New Outfall #1. Figure 5.4-17 shows existing conditions for New Outfall #1. Figure 5.4-18 shows more existing conditions for New Outfall #2 and New Outfall #1. Figure 5.3-19 plots 3D imaging of New Outfall #2 and New Outfall #1.

Figure 5.4-12. Detailed orthosonograph of New Outfall #2 and New Outfall #1.

Figure 5.4-13. Aerial photographs of New Outfall #2.

Figure 5.4-14. Existing conditions New Outfall #2.

Figure 5.4-15. Existing conditions New Outfall #2.

Figure 5.4-16. Aerial photographs of New Outfall #1.

Figure 5.4-17. Existing conditions New Outfall #1.

Figure 5.4-18. Existing conditions on New Outfall #1.

Figure 5.4-19. 3D imaging of New Outfalls 1 and 2.

5.4.3 Outfall 19

Figure 5.4-20 plots the detailed orthosonograph vicinity of Outfall 19. Figure 5.4-21 shows the oblique aerial photographs of Outfall 19. Figure 5.4-22 show the oblique aerial photographs of Outfall 19. Figure 5.4-23 shows existing conditions for Outfall 19. Figure 5.4-24 shows more existing conditions for Outfall 19. Figure 5.4-25 shows even more existing conditions for Outfall

19. Figure 5.4-26 plots 3D imaging of Outfall 19.

Figure 5.4-20. Detailed orthosonograph of Outfall 19.

Figure 5.4-21. Aerial photograph of Outfall 19.

Figure 5.4-22. Aerial photographs of Outfall 19.

Figure 5.4-23. Existing conditions of Outfall 19.

Figure 5.4-24. Existing conditions of Outfall 19.

Figure 5.4-25. Existing conditions of Outfall 19.

Figure 5.4-26. 3D imaging of Outfall 19.

6.0 Conclusions

1. This product consists of an overview and four reports on the four quadrants:

(1) outfalls 45 to 42A

(2) outfalls 41 to 36

(3) outfalls 36B to 29

(4) outfalls 28 through 19

2. The e4 team performed hydrographic surveys, sonar imaging, standard penetration test (SPT) borings, reflection seismology, photographic inventory, and land surveys in the nearshore, on the beach, and on the ridge.

3. The results produced surface topography and bathymetry, a Quaternary sand isopach map, a Top of Tertiary horizon, and maps of obstructions and debris.

4. The orthosonographs show sediment reflectivity, remnant piles, outfall debris, rip-rap, and large blocks.

5. The final bathymetry merges the USACE-NAN survey data, e4 single-beam results, and e4 multibeam-scanning results.

6. The field study combined land RTK survey, the LIDAR data, and professional data surveys to provide a complete topographic map of the area.

7. The orthosonographs and 3D imaging show that the groin heads are significantly larger than exposed subaerially. The orthosonographs reveal submarine exposures of the Tertiary sediments.

The orthosonographs show outfalls, sewer outfalls, and other obstructions to construction.

8. The sixteen borings (seven in the nearshore and nine on the beach) and the reflection seismology show that the stratigraphy consists of Quaternary sands overlying Tertiary sediments.

9. Subsurface in the project area consists of a relatively thin (~10ft) veneer of recent loose sands overlying an erosion surface in older more compact and stiff semi-consolidated Tertiary sediments.

10. The Quaternary sands consist mostly of Holocene beach deposits (Unit E). The average N-value in the Holocene sands measured 15.7. Pleistocene sands (Unit D) were encountered south of Poplar Brook. The average N-value in the Pleistocene sands measured 36.0. There is 1.5ft of clay near the base of the Pleistocene sands. Clay was not encountered in the Holocene sands.

11. The Tertiary sediments provide a bearing formation. The SPT borings penetrated three units (Unit C, Unit B, Unit A; younger to older) in the Tertiary. The average N-value in the three units measured 15.3, 19.4, and 16.8, respectively. The average plastic index measured in each of three units was 52.8, 19.7, and 3.0, respectively. The Tertiary sediments carry some gravel and fossils.

The three Tertiary units dip toward the southwest.

12. Unit A is exposed in highs on the seafloor. Units B and C have small irregular lithified rock areas less than 0.5ft thick of green siltstone. Green siltstone rock fragments occur throughout the beach.

13. The thin offshore Quaternary sands may limit the possibilities for moving well points seaward. The sands are fine to medium with permeabilities greater than 10 darcies. The Tertiary sediments have as much as 35% fines; that is, the grain size is less than 74 microns. The Tertiary sediments have permeabilities less than 10 millidarcies. That is, there is a three orders-of-magnitude difference in permeability between the Holocene sands and the Tertiary sediments.

14. At the beach, the thickness of Quaternary sands ranges from 4 to 12ft. In the offshore borings, the sands thicknesses ranged from 2 to 18ft. Offshore at roughly -35ft water depth, the sand thicknesses thin to zero. The offshore surface sands are thinner north of than south of Poplar Brook.

15. The Top of Tertiary map shows the top horizon of the impermeable and resistive Tertiary sediments.