Appendix I. Dredged Volume Estimates. Draft Contractor Document: Subject to Continuing Agency Review

Transcription

1 Appendix I Dredged Volume Estimates Draft Contractor Document: Subject to Continuing Agency Review

2 Interoffice Correspondence Date: April 6, 2007 To: L. Bossi (WHI) Copy: S. Thompson (WHI), B. Fidler (NNJ) From: D. Navon (TAM) Re: Sediment Removal Volume Estimate Methodology INTRODUCTION This memorandum outlines the methodology and results of the calculation for the sediment removal volumes from river mile (RM) 0 to RM8.3 (i.e., the Area of Focus) for the six remedial action alternatives considered in the Focused Feasibility Study (FFS). It is necessary to estimate sediment removal volumes to evaluate the feasibility of each remedial action alternative with respect to remedial action duration, dredged material management options, cost, and other considerations. The memorandum describes the data used for the calculations, methods used to calculate sediment volumes, and the results of the calculations for each remedial action alternative. DATA Bathymetric Survey Data obtained from a bathymetric survey conducted in 2004 by Rogers Surveying, Inc. for the United States Army Corps of Engineers (USACE) were used to approximate the current sediment surface. The bathymetric data are relative to the National Geodetic Vertical Datum of 1929 (NGVD29), which is 2.4 feet above Mean Low Water (MLW). To convert the NGVD29 bathymetric data to depths relative to MLW, a depth of 2.4 feet was subtracted from each datum.

3 L. Bossi (WHI) April 6, 2007 Page 2 of 13 Geotechnical Borings and Chemical Core Data Geotechnical borings were collected in The borings were logged and the depth of the fine-grained sediment (primarily silt) was estimated by a geologist by evaluating the boring logs. The depth of fine-grained sediment was used to approximate the depth of contamination. Geotechnical boring logs are provided in the Technical Report: Geophysical Survey (Aqua Survey, Inc., 2006). Data from historical sediment cores collected in 1991, 1993, and 1995 were used to estimate the depth of contamination (see the Methodology section discussion below). This historical sediment core dataset is described in detail in the Draft Geochemical Evaluation (Step 2) (Malcolm Pirnie, Inc., 2006). METHODOLOGY Sampling Locations Nineteen transects were drawn across the river (from bank to bank) to form 18 river sections (a river section is formed by two transects) between RM0 and RM8.3 (refer to the attached Figure I-1). Thirteen transects were placed where borings provided geotechnical data. Five additional transects were placed to refine the volume calculations in areas where the distance between transects was greater than approximately one-half mile. Note that the distance between transects Q (RM7.1) and R (RM8.3) is greater than one mile due to the lack of chemical core data in this area of the river. Also, three additional transects (A', B', and C') were drawn to calculate the area of the river outside of the limits of the authorized navigational channel between RM0.0 and RM0.9 for Alternative 1 (Figure I-1), which entails sediment removal from the shoals 1 at the mouth of the river. An additional transect, R, was drawn at RM8.1 for Alternatives 1, 3, 5 and 6, as the proposed depth of sediment removal changes at this river mile. Table 1 provides data regarding transect locations with respect to river miles. 1 Shoals are defined as areas located between the navigational channel and the shoreline.

4 L. Bossi (WHI) April 6, 2007 Page 3 of 13 Table 1: River Transects Used for Sediment Removal Volume Estimates Transect River Mile A (A') 0 B (B') 0.6 C (C') 0.9 D 1.4 E 1.7 F 2.5 G 2.9 H 3.5 I 3.8 J 4.3 K 4.7 L 5.3 M 5.8 N 6.4 O 6.7 P 7.0 Q 7.1 R 8.1 R 8.3 Average-End Area Calculation Sediment removal volumes for the majority of the river were estimated using average-end area calculations. This method involved determining the cross-sectional area for sediment removal at each transect based on the desired sediment depth and channel configuration for each remedial alternative (refer to the Discussion section below). Then, the cross-sectional areas for both transects comprising the river section were averaged and multiplied by the length of the river section to estimate the sediment removal volume. This calculation assumes that the change in the sediment surface between the two transects is linear. Therefore, the greater the distance between adjacent transects, the greater the likelihood that the average-end area calculation contains error due to irregularities in the sediment surface and the width of the river.

5 L. Bossi (WHI) April 6, 2007 Page 4 of 13 Assumptions for Alternatives For Alternatives 1 and 6, which involve the removal of fine-grained sediment from the shoals, the depth of sediment to be removed was determined using geotechnical and chemical core data (see Figure I-1 for core locations). The geotechnical cores provided data on the depth of fine-grained sediment, which is assumed to be associated with the presence of contamination. The chemical cores provided the depth of mercury contamination. Mercury was selected as a surrogate to identify depth of contamination because mercury contamination occurs deeper in the sediment bed relative to 2,3,7,8- tetrachlorodibenzodioxin (2,3,7,8-TCDD) and polychlorinated biphenyls (Total PCB) (Malcolm Pirnie, Inc., 2006). The chemical cores included both complete cores (where mercury concentrations peaked and declined to zero above the core bottom) and incomplete cores (where a rising mercury concentration gradient or a non-zero mercury concentration exists at the core bottom). The locations of all of the cores were plotted to determine which cores fell closest to each transect. Then, the depth of contamination indicated by each core was determined. For each type of core (i.e., complete chemical core, incomplete chemical core, and geotechnical core), the average depth of contamination for each transect was estimated. The average depths of contamination indicated by the complete cores, the incomplete cores, and the depth of fine-grained sediment were compared, and the deepest depth was selected to be representative of contamination for the associated transect. One foot was added to these estimated depths to account for dredging inaccuracy (i.e., overdredge allowance). Table 2 presents the average depth of sediment removal for the shoals at each transect.

6 L. Bossi (WHI) April 6, 2007 Page 5 of 13 Table 2: Depth for Sediment Removal from Shoals for Alternatives 1 and 6 Transect Depth (ft) 1 A' 10.2 B' 6 C' 12.2 D 13.4 E 14.3 F 7.4 G 10.7 H 14.9 I 7 J 17.9 K 8.7 L 13 M 13 N 6.5 O 6.5 P 4.5 Q 5 R 2.9 R Depths are the selected depth of contamination plus a one foot to account for dredging inaccuracy The side slopes of the cross-sectional areas to be excavated for all of the remedial action alternatives were constrained to be no greater than a 3 horizontal to 1 vertical slope (3H:1V). The resultant transect cross-sections were used to calculate sediment removal volumes using the average-end area calculation method described above. For alternatives requiring placement of cap material, the shoals would be pre-dredged only if hydrodynamic flood modeling showed that pre-dredging prior to cap placement would result in acceptable flooding results (refer to Appendix G Cap Erosion and Flood Modeling ). For Alternatives 3, 4, 5, and 6, it is assumed that pre-dredging in the shoals is required prior to cap placement. For these alternatives, it is assumed that three feet of sediment are pre-dredged to accommodate a two-foot thick sand cap and one foot of dredging inaccuracy. Several alternatives assume the placement of an armor layer over a sand cap in areas of unacceptable erosion as defined by hydrodynamic modeling. As discussed in Section 4.0

7 L. Bossi (WHI) April 6, 2007 Page 6 of 13 of the FFS, the median stone size for the armor material has been estimated at six inches. Placement of a stone of this size would require that the thickness of the armor layer be approximately 18 inches to ensure adequate coverage of the sand, with an additional allowance of six inches for a filter material to be placed on the sand prior to stone placement. An additional one foot of sediment removal is assumed to account for dredging inaccuracies; therefore, the total depth of additional sediment removal for areas to be armored is three feet. However, for Alternatives 3, 4, 5, and 6 only two feet of sediment removal is required since dredging inaccuracies are taken into account in the dredging of the navigation channel and the pre-dredging in the shoals to make room for the cap. Tidal Mudflat Estimation Tidal mudflats, which are intermittently exposed and submerged based on tidal action, would be pre-dredged to three feet for each alternative to accommodate a one-foot thick sand cap, one foot of mudflat reconstruction material, and one foot to account for dredging and placement inaccuracies. The tidal mudflat areas were delineated by analyzing the 2-foot contours from the Rogers Surveying, Inc bathymetric dataset. Based on tidal gauges, the water level of the river fluctuates between minus 2 feet elevation (relative to NGVD1929) and the shoreline during low and high tides. Areas between the -2-foot elevation and the shoreline were designated as mudflats. Areas with widths less than 50 feet were not considered mudflats and were excluded. The results of this delineation were used to calculate the sediment removal volume from the mudflats. The resulting sediment volume to be removed from the mudflats is approximately 208,000 cubic yards (CY) for each remedial alternative. The conceptual design figures in Section 4.0 of the FFS show the locations of the delineated mudflats. Table 3 presents the mudflat areas and sediment removal volumes from the mudflats per river mile.

8 L. Bossi (WHI) April 6, 2007 Page 7 of 13 Table 3: Mudflats Areas and Sediment Removal Volumes by River Mile River Miles Mudflats (acres) Mudflats Volume (CY) , , , , ,892 Total ,265 DISCUSSION Alternative 1: Removal of Fine-grained Sediment from Area of Focus Alternative 1 would involve the removal of fine-grained sediment from the horizontal limits of the federally authorized navigation channel as well as from the adjacent shoal and mudflat areas. Within the horizontal limits of the federally authorized navigation channel, the depth of fine-grained sediment has been shown to correspond well with the depth of historical dredging. For this reason, the depth of dredging within the horizontal limits of the navigation channel was assumed to be the historically constructed channel depth plus an additional three feet to account for historical overdredging (two feet) and dredging accuracy (one foot). For this alternative, the resulting sediment removal depth would be 33 feet MLW for RM0.0 to RM2.5, 23 feet MLW for RM2.5 to RM4.6, 19 feet MLW for RM4.6 to RM7.1, 19 feet MLW for RM7.1 to RM8.1, and 13 feet MLW for RM8.1 to RM8.3. The volume of sediment removal from the shoals located between transect C (RM0.9) and transect R (RM8.3) was calculated using the average-end area calculation. The area at the mouth of the river between the southern Study Area boundary and transect A' was not suited for average-end area calculations because the width of the river changes dramatically in this segment. For this portion of the river, the surface area was calculated using Geographical Information System (GIS), and the depth of sediment removal was determined to be 2.8 feet based on the average of two cores collected from this area.

9 L. Bossi (WHI) April 6, 2007 Page 8 of 13 Transects A', B', and C' were drawn to calculate sediment removal volumes for the areas at the mouth of the river. The length between these transects was estimated using geometrical approximations from the triangular areas formed by these transects. The depth of contamination was determined as described under the Methodology section (i.e., using core data), and the average-end area method was applied using the estimated length between transects. The volume of sediment to be removed from the mudflats was estimated at 208,000 CY as described above in the Methodology section. Figure 4-1 in the text of the FFS shows the cross sections of sediment removal for each transect for Alternative 1. Table 4 (attached) presents the calculated volumes of sediment to be removed from each river section. Alternative 2: Engineered Capping of Area of Focus Alternative 2 would sequester the contaminated sediments in the Area of Focus by means of an engineered cap. The volume of sediment removal for Alternative 2 consists of areas to be pre-dredged for armor placement as well as mudflat areas that will be excavated for purposes of mudflat reconstruction. These areas are delineated on Figure 4-2 in the FFS. Table 5 (attached) presents the volume of sediment to be removed from each river mile for Alternative 2. Alternative 3 Engineered Capping of Area of Focus Following Reconstruction of Federally Authorized Navigation Channel Alternative 3 would involve the removal of sediment from the horizontal limits of the federally authorized navigation channel as well as from the adjacent shoal and mudflat areas. The depth of dredging within these horizontal limits is assumed to be the historically constructed channel depth plus an additional three feet to account for historical overdredging (two feet) and dredging accuracy (one foot). For this alternative, the approximate depth of sediment removal in the navigation channel would be 33 feet MLW for RM0.0 to RM2.5, 23 feet MLW for RM2.5 to RM4.6, 19 feet MLW for RM4.6 to RM7.1, 19 feet MLW for RM7.1 to RM8.1, and 13 feet MLW for RM8.1 to RM8.3. A

10 L. Bossi (WHI) April 6, 2007 Page 9 of 13 two-foot layer of backfill would then be placed to mitigate for any remaining fine-grained sediment and/or dredging residuals. Alternative 3 also requires the pre-dredging of shoal areas to accommodate an engineered cap as well as pre-dredging in certain areas to accommodate armoring material as discussed above in the Methodology section. Mudflat areas would be pre-dredged as discussed under the Methodology section above. The side slopes of the areas to be excavated were constrained to be no greater than 3H:1V. The conceptual design of Alternative 3 is shown on Figure 4-3 in the FFS. Table 6 (attached) presents the volume of sediment to be removed from each river section for Alternative 3. Alternative 4 Engineered Capping of Area of Focus Following Construction of Navigation Channel to Accommodate Current Usage As described in Section 4.0 of the FFS, the New York District of the USACE has studied the current navigation usage of the river. The dimensions of the navigation channel necessary to accommodate current usage were estimated based on this Study. Implementation of Alternative 4 entails the construction of a channel of these dimensions followed by placement of an engineered cap over the entire Area of Focus (RM0 to RM8.3). From RM0 to RM1.2, the depth of dredging within the horizontal limits of the federally authorized navigation channel is assumed to be the historically constructed channel depth plus an additional three feet to account for historical overdredging (two feet) and dredging accuracy (one foot). The side slope would be constructed at a slope of 3H:1V. After sediments are removed from the federally authorized navigation channel to the depth specified above (i.e., 33 feet MLW), it is assumed that minimal fine-grained sediment would remain in the channel. Therefore, a two foot backfill layer would be placed to mitigate for any remaining fine-grained sediment and/or dredging residuals.

11 L. Bossi (WHI) April 6, 2007 Page 10 of 13 From RM1.2 to RM2.5, the depth of dredging within the horizontal limits of the federally authorized navigation channel is assumed to be the depth required by the design vessel (13 feet), plus an additional three feet for underkeel clearance, plus an additional nine feet to accommodate the necessary cap components that would be placed. The side slope would be constructed at a slope of 3H:1V. Following removal to the depth described above, it is possible that additional, un-targeted contaminant inventory would remain in place. Therefore, it is assumed that an engineered cap would be placed on the channel bottom. In the side slope and shoals of RM0 to RM2.5, and throughout the rest of the Area of Focus from RM2.5 to RM8.3, it is likely that additional, un-targeted contaminant inventory would remain in place. Therefore, pre-dredging to accommodate an engineered cap would be necessary in these areas. In areas of unacceptable erosion, as identified in Appendix G Cap Erosion and Flood Modeling, stone would be used as armor material, and the areas to be armored would be pre-dredged as described in the Methodology section above. Mudflat areas would be pre-dredged as discussed under the Methodology section above. The conceptual design of Alternative 4 is shown on Figure 4-4 of the FFS. Table 7 (attached) presents the volume of sediment to be removed from each river section for Alternative 4. Alternative 5- Engineered Capping of Area of Focus Following Construction of Navigation Channel for Future Use As described in Section 4.0 of the FFS, New Jersey Department of Transportation (NJDOT) has estimated the dimensions of the navigation channel necessary for future river traffic. Alternative 5 entails the construction of a channel of these dimensions followed by the placement of an engineered cap over the Area of Focus. From RM0 to RM1.2, the depth of dredging within the horizontal limits of the federally authorized navigation channel is assumed to be the historically constructed channel depth plus an additional three feet to account for historical overdredging (two feet) and

12 L. Bossi (WHI) April 6, 2007 Page 11 of 13 dredging accuracy (one foot). The side slope would be constructed at a slope of 3H:1V. Following removal of the sediment from within the horizontal limits of the federally authorized navigation channel to the depth specified above (i.e., 33 feet MLW), it is assumed that minimal fine-grained sediment would remain in the channel. Therefore, a two foot backfill layer would be placed to mitigate for any remaining fine-grained sediment and/or dredging residuals. From RM1.2 to RM2.5, the depth of dredging within the horizontal limits of the federally authorized navigation channel is assumed to be the depth required by the design vessel (13 feet), plus an additional three feet for underkeel clearance, plus an additional nine feet to accommodate the necessary cap components that would be placed. The side slope would be constructed at a slope of 3H:1V. Following removal to the depth described above (i.e., 25 feet MLW), it is possible that additional, un-targeted contaminant inventory would remain in place. Therefore, an engineered cap would be placed on the channel bottom. From RM2.5 to RM3.6, the depth of dredging within the horizontal limits of the federally authorized navigation channel is assumed to be the depth required by the design vessel (13 feet), plus an additional three feet for underkeel clearance, plus an additional nine feet to accommodate the necessary cap components that would be placed. This alternative would require sediment removal to 25 feet MLW. However, the depth of the authorized historical channel from RM 2.5 to RM 3.6 is 20 feet. An addition of three feet to the authorized depth to account for historical overdredging (two feet) and dredging accuracy (one foot) result in a historical channel depth of 23 feet MLW (not 25 feet MLW). Since dredge depth is limited to the historical channel depth, it is assumed that sediment will be removed to a depth of 23 feet MLW, and a full cap is not required since all of the finegrained sediment will presumably be removed (i.e., two feet of backfill will be applied as opposed to placement of a full cap). The side slope would be constructed at a slope of 3H:1V.

13 L. Bossi (WHI) April 6, 2007 Page 12 of 13 From RM3.6 to RM8.3, the depth of dredging within the horizontal limits of the federally authorized navigation channel is assumed to be the depth required by the design vessel (seven feet), plus an additional three feet for underkeel clearance, plus an additional nine feet to accommodate the necessary cap components that would be placed. This alternative will require sediment removal to 19 feet MLW. However, the depth of the authorized historical channel from RM8.1 to RM8.3 is 10 feet. An addition of three feet to the authorized depth to account for historical overdredging (two feet) and dredging accuracy (one foot) results in a historical channel depth of 13 feet MLW (not 19 feet MLW). Since dredge depth is limited to the historical channel depth, it is assumed that sediment will be removed to a depth of 13 feet MLW from RM8.1 to RM8.3. Following removal to the depth described above (i.e., 19 feet MLW from RM3.6 to RM8.1 and 13 feet from RM8.1 to RM8.3), it is possible that additional, un-targeted contaminant inventory would remain in place from RM3.6 to RM4.6; however, it is assumed that minimal fine-grained sediment would remain in the channel from RM4.6 to RM8.3. Therefore, an engineered cap would be placed on the channel bottom from RM3.6 to RM4.6 and a two foot thick backfill layer would be placed to mitigate for any remaining fine-grained sediment and/or dredging residuals from RM4.6 to RM8.3. The side slope would be constructed at a slope of 3H:1V. In the side slope and shoal areas of RM0 to RM8.3, it is likely that additional, un-targeted contaminant inventory would remain in place. For this reason, it is assumed that an engineered cap would be placed in these areas. Alternative 5 requires the pre-dredging of shoal areas to accommodate an engineered cap, as well as pre-dredging in certain areas to accommodate armoring material as discussed above in the Methodology section. Mudflat areas would be pre-dredged as discussed under the Methodology section above. The conceptual design of Alternative 5 is shown on Figure 4-5 in the FFS. Table 8 (attached) presents the volume of sediment to be removed from each river section for Alternative 5.

14 L. Bossi (WHI) April 6, 2007 Page 13 of 13 Alternative 6 Engineered Capping of Area of Focus Following Construction of Navigation Channel for Future Usage and Removal of Fine-grained Sediment from Primary Inventory Zone and Primary Erosional Zone The conceptual design of Alternative 6 is identical to that of Alternative 5 with the exception that in the Primary Erosional Zone and the Primary Inventory Zone the depth of dredging is assumed to be the estimated depth of fine-grained sediment plus an additional one foot to account for dredging accuracy. (The delineations of the Primary Erosional and Primary Inventory Zones are discussed in Section 2.3 of the FFS.) The Primary Erosional Zone comprises approximately 68 acres located between RM3.7 and RM5.4. The Primary Inventory Zone comprises approximately 63 acres between RM2.4 and RM3.6. The estimated depth of fine-grained sediment in these zones was derived using the geotechnical and chemical core data as discussed above in the Methodology section (Table 2). The conceptual design of Alternative 6 is shown on Figure 4-6 in the FFS. Table 9 (attached) presents the volume of sediment to be removed from each river section for Alternative 6. SUMMARY Table 10 (attached) summarizes estimated sediment removal volumes for all of the remedial action alternatives considered in the FFS. The values have been rounded to the nearest thousand cubic yards. REFERENCES Aqua Survey, Inc., Technical Report, Geophysical Survey, Lower Passaic River Restoration Project. June Malcolm Pirnie, Inc., Draft Geochemical Evaluation (Step 2). Lower Passaic River Restoration Project. March 2006.

15 Attached Tables (Table 4 through Table 10)

16 Table 4: Alternative 1 - Volumes of Sediment to be Removed Navigation Component Section N/A Contamination Component Alternative 1 Average Cross Sectional Area [Sq Ft] Length of Section [Ft] Volume of Section [CY] Section Average Surface Area Average Depth of [Sq Ft] Section [Ft] Area of Focus Southern Boundary - A' 3,751, ,082 Section Average Cross Sectional Area [Sq Ft] Length of Section [Ft] Left Shoal 1, ,535 2,992 A' - B' Channel 4, ,626 Right Shoal 23,827 2, ,528 Left Shoal 1,215 75,884 B' -C' Volume of Section [CY] Volume of Section [CY] Channel 4,686 1, ,788 Right Shoal 14,281 1, ,149 Left Shoal 1, ,263 C' - D Channel 4,931 2, ,607 Right Shoal 10, ,050 Left Shoal 1,394 95,377 D - E Channel 5,273 1, ,908 Right Shoal 3, ,479 Left Shoal 2, ,100 E -F Channel 5,727 3, ,887 Right Shoal 1, ,387 Left Shoal 1, ,238 F -G Channel 3,099 2, ,772 Right Shoal ,993 Left Shoal 1, ,201 G - H Channel 3,560 3, ,726 Right Shoal ,428 Left Shoal 1,418 77,616 H - I Channel 3,655 1, ,132 Right Shoal ,722 Left Shoal 2, ,317 I - J Channel 3,827 2, ,131 Right Shoal 1, ,861 Left Shoal 1, ,255 J - K Channel 3,344 1, ,957 Right Shoal 1,176 85,054 Left Shoal ,766 K - L Channel 2,129 3, ,129 Right Shoal ,236 Left Shoal ,426 L - M Channel 1,701 2, ,319 Right Shoal ,823 Left Shoal ,829 M - N Channel 949 3, ,291 Right Shoal ,829 Left Shoal ,364 N - O Channel 1,938 1, ,822 Right Shoal ,836 Left Shoal ,853 O - P Channel 2,744 1, ,587 Right Shoal ,119 Left Shoal ,534 P - Q Channel 2, ,841 Right Shoal 258 4,541 Left Shoal ,672 Q - R' Channel 1,608 5, ,309 Right Shoal ,302 Left ,560 R' - R Center 372 1,056 14,549 Right 76 2,972 Total Contamination Component Volume [CY] 10,751,562 Pre-dredging in Armor Areas RM Area [Sq Ft] Depth [Ft] Volume of Section [CY] N/A Pre-dredging in Mudflats Areas Total Pre-dredging in Mudflats Areas Volume [CY] 208,265 Total Volume [CY] 10,959,827

17 Table 5: Alternative 2 - Volumes of Sediment to be Removed Pre-Dredging Armor Areas Alternative 2 RM Area [Sq Ft] Depth [Ft] Volume of Section [CY] , , ,190, , ,883, , ,346, , ,174, , ,336, , , ,334 Total Pre-Dredging Armor Areas Volume [CY] 934,099 Pre-dredging in Mudflats Areas Total Pre-dredging in Mudflats Areas Volume [CY] 208,265 Total Volume [CY] 1,142,364

18 Table 6: Alternative 3 - Volumes of Sediment to be Removed Navigation Component A - B B - C C - D D - E E - F F - G G - H H - I I - J J - K K - L L - M M - N N - O O - P P - Q Q - R' R' - R Total Navigation Component Volume [CY] Contamination Component N/A Section Section Pre-dredging in Armor Areas Alternative 3 Average Cross Sectional Area [Sq Ft] Length of Section [Ft] Volume of Section [CY] 4,248 2, ,741 5,610 1, ,490 6,555 2, ,707 7,261 1, ,941 8,084 3,960 1,185,580 4,337 2, ,137 4,627 3, ,805 4,949 1, ,958 5,244 2, ,766 4,414 1, ,341 2,676 3, ,390 2,233 2, ,137 1,356 3, ,045 2,483 1, ,092 3,523 1, ,765 3, ,915 2,223 5, , ,056 28,395 6,718,578 Average Depth of Contamination [Ft] Area of Section [Sq Ft] Volume of Section [CY] RM Area [Sq Ft] Depth [Ft] Volume of Section [CY] , , , , , , , ,732 Total Pre-dredging in Armor Areas Volume [CY] 52,218 Pre-dredging in Mudflats Areas Total Pre-dredging in Mudflats Areas Volume [CY] 208,265 Total Volume [CY] 6,979,061

19 Table 7: Alternative 4 - Volumes of Sediment to be Removed Navigation Component Section A - B B - C C - D D - E E - F F - G G - H H - I I - J J - K K - L L - M M - N N - O O - P P - Q Q - R Total Navigation Component Volume [CY] Contamination Component Average Cross Sectional Area [Sq Ft] Alternative 4 Length of Section [Ft] Volume of Section [CY] 4,248 2, ,741 5,610 1, ,490 6,555 2, ,662 4,085 1, ,561 4,692 3, ,087 1,650 2, ,382 1,426 3, ,626 1, ,494 1,670 2, ,352 1,467 1, ,146 1,165 3, ,250 1,147 2,323 98,693 1,043 3, ,320 1,069 1,795 71,077 1,144 1,531 64,849 1, , , ,126 3,794,779 Section Average Depth of Contamination [Ft] Area of Section [Sq Ft] Volume of Section [CY] N/A Pre-dredging in Armor Areas RM Area [Sq Ft] Depth [Ft] Volume of Section [CY] , , ,877, , ,030, , , , ,181, , , ,497 Total Pre-dredging in Armor Areas Volume [CY] 429,076 Pre-dredging in Mudflats Areas Total Pre-dredging in Mudflats Areas Volume [CY] 208,265 Total Volume [CY] 4,432,120

20 Table 8: Alternative 5 - Volumes of Sediment to be Removed Navigation Component A - B B - C C - D D - E E - F F - G G - H H - I I - J J - K K - L L - M M - N N - O O - P P - Q Q - R' R' - R Total Navigation Component Volume [CY] N/A Section Contamination Component Section Pre-dredging in Armor Areas Average Cross Sectional Area [Sq Ft] Length of Section [Ft] Volume of Section [CY] 4,249 2, ,797 5,609 1, ,427 6,971 2, ,087 4,085 1, ,561 4,689 3, ,720 4,732 2, ,670 5,316 3, ,843 3, ,648 3,751 2, ,106 2,969 1, ,787 2,675 3, ,329 2,233 2, ,137 1,356 3, ,045 2,483 1, ,092 3,523 1, ,765 3, ,915 2,223 5, , ,056 28,395 5,845,697 Average Depth of Contamination [Ft] Alternative 5 Area of Section [Sq Ft] Volume of Section [CY] RM Area [Sq Ft] Depth [Ft] Volume of Section [CY] , , , Total Pre-dredging in Armor Areas Volume [CY] 94,509 Pre-dredging in Mudflats Areas Total Pre-dredging in Mudflats Areas Volume [CY] 208,265 Total Volume [CY] 6,148,471

21 Table 9: Alternative 6 - Volumes of Sediment to be Removed Navigation Component Section A - B B - C C - D D - E E - F K - L (half) L - M M - N N - O O - P P - Q Q - R' R' - R Total Navigation Component Volume [CY] Contamination Component Average Cross Sectional Area [Sq Ft] Alternative 6 Length of Section [Ft] Volume of Section [CY] 4,249 2, ,797 5,609 1, ,427 6,971 2, ,087 4,085 1, ,561 4,689 3, ,720 1,996 3, ,973 2,233 2, ,137 1,356 3, ,045 2,483 1, ,092 3,523 1, ,765 3, ,915 2,223 5, , ,056 28,395 3,899,287 Section Average Cross Sectional Area [Sq Ft] Length of Section [Ft] Volume of Section [CY] F -G Right 1, ,238 Center 3,099 2, ,772 Left ,993 G - H Right 1, ,201 Center 3,560 3, ,726 Left ,428 H - I Right 1,418 77,616 Center 3,655 1, ,132 Left ,722 I - J Right 2, ,317 Center 3,827 2, ,131 Left 1, ,861 J - K Right 1, ,255 Center 3,344 1, ,957 Left 1,176 85,054 K - L Right ,766 Center (half) 871 3, ,543 Left Total Contamination Component Volume [CY] 0 0 2,853,712 Pre-dredging in Armor Areas RM Area [Sq Ft] Depth [Ft] Volume of Section [CY] , , , ,636 Total Pre-dredging in Armor Areas Volume [CY] 48,670 Pre-dredging in Mudflats Areas Total Pre-dredging in Mudflats Areas Volume [CY] 208,265 Total Volume [CY] 7,009,934

22 Table 10: Volumes of Sediment to be Removed for each Remedial Action Alternative Alternative Number Description Nav Channel + shoals/side slopes (CY) Room for Armor Layer (CY) Mudflats (CY) TOTAL VOLUME (CY) 1 1 Dredging 10,751, ,265 10,960,000 2 Capping 0 934, ,265 1,142,000 3 NCC 2 - Authorized Channel 6,718,578 52, ,265 6,979,000 4 NCC - Current Use Channel 3,794, , ,265 4,432,000 5 NCC - Future Use Channel 5,845,697 94, ,265 6,148,000 6 NCC - Future Use Channel + Dredging Primary Erosion and Inventory Zones 6,752,999 48, ,265 7,010,000 1 Total Volumes are rounded to the nearest thousand 2 NCC = Navigationally Constrained Capping

23 Figures

24 J ³ 8 R' R 7 P Q O N 6 M L 5 K 4 I H 3 G F 2 E D Legend 1 C C' Map Document: (S:\Projects\PASSAIC\MapDocuments\ CERCLA\Figure3_Thalia_Memo.mxd) 1/24/ :18:42 AM Geotechnical Borings Complete Mercury Profiles Incomplete Mercury Profiles Transects Shoreline as defined by the New Jersey Department of Environmental Protection Area of Focus Navigation Channel Miles Sediment Cores RM0 to RM8.3 Lower Passaic River Restoration Project B B' A 0 A' Note: Samples include historical and non-historical sediment cores. Figure I-1 June 2007 Draft