In 2008 June, a contract was signed between the US Army Corps of  Engineers and Port Authority of Philadelphia Regional to commence a $379-million deal that aimed to increase the depth of the Delaware River's shipping channel and was estimated to take a period of 5 years to complete (Kauffman 1662). According to the proposal, the deeper end of the channel was 40 feet, and this depth was to be increased to 45 feet. The deeper channel would permit Delaware River ports to remain competitive and efficient in cargo transportation, offer secure passage, and create more job opportunities within the region. The project aimed to eliminate dredging material estimated to be 26 million cubic yards, of which approximately 35% of the eliminated material would be used for beach nourishment and wetland creation. The supervising organization, the Corps of US Army Engineers, made an estimation that the project will be able to generate annual benefits up to $40 to the economy of the US. The deepened port would ensure that Phillaport is not marginalized in the new vessel traffic competition (Grigalunas 1). The deepened 100-mile channel will allow Philadelphia ports to manage vessels that can ship up to 15,000 TEU or 15,000 20-foot. At 40 feet deep, the channel could handle barely 12,000 TEU. Also, the deepened channel will permit the ships to enter Philadelphia while fully loaded, contrary to the earlier approached where the ships could make some stops on other ports to lighten the cargo being shipped.

Since its approval in 1992 by the Congress, the project survived many legal actions coming from the environmentalists, who believed that the project was more of a harm to the animals living in the ocean (marine life), and from the bordering states, who believed that that the project had any significant benefit to the accessibility of the Philadelphia port shipping environment. Again, after the dredging process was eventually commenced in 2010, the reliability of federal funding becomes an issue, causing a delay in the progress of the project and escalation of costs.  The Great Lakes Dredge & Dock Company, which the corps contracted, dislodged a more significant part of the bedrock using explosives. However, to mitigate harm brought to migrating sturgeon, the blasting process was limited to only four months in winter. Several regions couldn't be blasted since they were noted to be closer to buried Comcast fiber-optic cable (there are also over 20 other separate utility cables crossing under the Delaware River) and fuel and gas pipelines. The corps was forced to import Europe an underwater hammer with around eight-ton capacity for breaking up the most challenging bedrock that was closer to the pipeline crossings. The supervising agent also extended their contract with the contractor to return the New York, the monster dredge, which was explicitly used to claw out the hardest rock. With the end of the bock blast Contract (eighth construction agreement), the project to extend the Delaware River Main Channel to 45 feet deeper was finished in February 2020. The whole project involved ten contracts and several dredging and rock removal approaches, and productive utilization of dredged material. 

Several East Coast ports had already deepened their channels to ensure that huge ships coming through the Panama Canal, which was enlarged in 2016, could be accommodated. These ports include Savannah, Charleston, Jacksonville, and Everglades. While the Delaware River deepening project was being undertaken, the channels of Baltimore and New York had been deepened to 50 feet. On the other hand, Congress had given the go-ahead to the extension of Norfolk to 55 feet depth.  This paper seeks to discuss the Delaware River's infrastructure system and specifically the deepening of the main channel. The areas discussed will be the project description and construction, feasibility analysis, financial analysis, and environmental impact. 

Project Description

1. Design considerations

From the project displayed in FIGURE 3, it is evident that the project offers for modification of the prevailing channel of Delaware River Federal Navigation.  At Mean Low water, the modification ranges from 40 to 45 feet and one foot over depth dredging requirement, after the prevailing alignment of the channel from Delaware Bay to Camden, Harbor of Philadelphia, New Jersey, Beckett Street Terminal and Pennsylvania. The slide slopes of the channel are one vertical and three horizontals. The project also involves the deepening of a prevailing Federal access channel at a depth of 45 feet to New Jersey, Camden, and Terminal of Beckett Street. The present turning basin lying next to the previous Philadelphia Naval Shipyard might not be excavated because it is not counted as a 45-foot project. Besides, the addition and relocation of buoys at the bend 12 modified channels are included as part of the Federal project. A plan view of the proposed channel bends and Marcus Hook Anchorage are displayed.

According to (), "The Delaware River Main Stem and Channel Deepening Scheme,  New Jersey, Pennsylvania, and Delaware were approved by Public Law 102-580, Section 101(6) of the Water Resources Development Act of 1992." Before this project scheme, that the Delaware River had been deepened four times in 1898 when it was dredged from its original depth of 17 to 24 feet to 26 feet deep (The channel has maintained 40 feet depth from1942). The high cost of getting out the bedrock begs the concern about whether it would ever be commercially possible for the contractors to move further than 45 feet since it would meet even more soil, and individual pipes will need to be moved. The project stretched too deep waters in Delaware Bay from Allegheny Avenue in Philadelphia (figure 2). The channel width ranges from 1000 feet in Philadelphia Harbor to 1,000 feet in Delaware Bay. The channel across Philadelphia Harbor was 40 feet deep on the west side and 37 feet deep on the east side. The project could allow for the expansion of essential curves. In Delaware River, there exist 19 anchorages. The project involved 12 training dikes in eliminating channel and anchorage shoaling or ease the costs of dredging and disposal. Dredging management and dumping of dredged material were made the responsibility of the Federal Government. Figure 2 shows the picture of the project proposal by the US corps Engineers. 

The 400 feet channel's width dimension in Harbor of Philadelphia was centered on the design vessel 120,000 deadweight tonnage dry bulk vessel that had a width of 128 feet and length of 830 feet. The 800 and 1000 feet channel's widths were centered on the tank with 145,000 deadweight tonnage, 931 feet long and 145 feet wide. The navigation of similar parameters could be allowed by the channel dimensions. This means that the channel could permit two-way traffic under full usage of tide range by incoming vessels.  The channel widths were obtained from "Hydraulic Design of Deep Draft Navigation Projects," EM 110-2-1613, 8, Aug 1983, for two-way traffic. This design was evaluated by the Waterway Experimentation Station (WES), US Army owned, and EM 110-2-1613, and the "Pilot's Association for Bay and River Delaware by use of a ship simulator model following the regulations outlined in ER 1110-2-1461,  Design  of Navigation Channel Using Ship Simulation Technique" dated 31 October 1989." The Delaware River Pilots who engaged in the practical model tests discovered that there were perceivable variations in channel configuration in the controlling of the ships in the meeting scenario. Delaware River Pilots typically consider a vessel to be out of balance when the volume of rudder and thrust needed much exceeds those usually used in a given situation. If a significant increase in steering or power is required to retain the vessel's stability, the vessel is not deemed to be in control, even though the vessel does not encounter collision or grounding. The physical model research software could not identify the quantitative degree of speed reduction and the resulting rise in travel time-correlated to the channel transit. The physical model experiments revealed that the navigation channel was appropriate for the protection of the overtaking exercises. If traffic is one where overtaking and passing is needed anywhere within the navigation channel, any narrowing of the navigation channel too far less than 800 feet would result in dangerous overtaking circumstances. This will be especially true for inbound ships filled to a depth of more than 39 feet.

The basis of the construction involved three categories: preparing the upland so as it can be able to receive the dredged material, wetland restoration site constriction, and sand stockpile site creation. The dredging of the sand was done using hopper dredgers and hydraulic pipes. The rock part was removed by blasting, drilling, and excavation using a bucket dredge. The Corps of Engineers would maintain the anchorage and the Federal channel concerning the project set dimensions, thus offering maintenance in areas that more subjected to shoaling areas as required.

1. Channel Bend Modifications

The bend widening total in the project plan was estimated to be around 216 acres that would extended in depth from  41.7 mean low water average  to around 46 feet mean low water. The substrate is 144 acres silt, 50 acres sandy silt, and 22 acres sandy. 

Table 1:

1. Initial Channel Dredging

In the first deepening, the material was dredged and put in hopper dredges and hydraulic pipelines in a confined disposal site for productive purposes in Delaware Bay.   Additionally, the rock of approximately 230,000 cubic yards was removed in the region around Marcus Hook, Pennsylvania. The following reaches were completed: Reach C, which stretches to near Chesapeake & Delaware Canal from the Delaware Memorial Bridge completed September 2010. From Reach C, material estimated to estimate 3,595,000 cubic yards (CY) were drawn and piled in Killcohook. The Reach B was completed by 29 December 2011. Material estimated to around 770,000 CY was removed and placed Pedricktown South, another Federally-owned CDF. Reach A dredging operations began in September 2012 and concluded in February 2013. The dredging zone stretched to near upstream of Chester Island from a region near the Walt Whitman Bridge. A material estimated to be around 1,360,000 CY was removed and retained in National Park CDF. The dredging of Reach D started in January 2013 and was finalized in 2013 May. The dredging zone to the Delaware State Cedar Creek Wildlife Management Area stretched from a zone near Port Penn, DE. An estimate of around 1 million cubic yards was removed and pilled in Artificial Island CDF. All the CDFs used were federally-owned. The original dredging capacities are spread within the project reaches, as shown in Table 1 below:

Table 2: dredging quantities for various reaches

1. Rock blasting 

Roughly 229,000CY of rock the Delaware River around the Marcus Hook was drawn to increase the navigation channel depth 47-R mean low water. Roughly 70,000CY, which covered 18 acres, was supposed to be detached by block blasting and the remaining part were to be removed using other mechanical approaches. In the area with Delaware Estate, roughly 22,000CY of bedrock would be blasted. The block blasting process involves drilling holes on the rock, and the drilled holes are filled with explosives to exert pressure on the rock that is to be broken. The process of blasting is done repetitively, and alternatively, another approach would be using a shaped charge which achieves block blasting. 

1. Disposal of dredge materials

As a result of to the constrained space and the amount of material to be dredged, the supervisor secured a four year retaining sites for the initial part of the project. This was also done to make sure that bulk dredging volume couldn’t overtop the channel bends, and ensure appropriate thickness for drying and control of the zones, and allow for efficient distribution dredge materials over the period of initial dredging phase of the project. Before commencing the main project, an estimation of the disposal areas holding capacities were made based on the available federal owned disposal sites. The estimation of the dredge material capacity from the 45 feet channel deepening and dredge maintenance capacity of existing 40 feet channel as from the date of commencing the project were projected for a four-year period. After completion of the project, projection for 45 deep channel maintenance dredge for a period of 50 years were made. In order to calculate the realistic life cycle of particular   disposal sites some fundamental assumptions were made:

  1. Wet to dry ratio or Shrinking factor = 0.67 - 0.80*

 2. Bulking Factor = 1.5 - 1.8*

 The values of these factors are subject to variation according to the material characteristics 

For instance, 20,000 cubic yards of a material in a place, when removed and placed in a disposal site with a bulk factor 1.7 would form a bulk to 34,000 cubic yards. On the other hand, for disposal area control and desiccation, given the shrinking factor is 0.67, the dredge material would therefore shrink to 6700 cubic yards in the disposal site. The concept was based on the existing information from Corps of Engineers Waterways Experiment Station series of studies and also Long Range Disposal Research. The breakdown as per project were as follows:

1. DELAWARE RIVER

 The first dredge material from the part of the river project (Reaches AA-D) would be placed at 9 available Federal CDFs. This include:National Park, Oldmans, Pedricktown North, Penns Neck, New Jersey, Killcohook, and so on.  The dredged material contains of rock, silt, clay,gravel and sand,. The three new disposal that would be acquired by the project benefactor, Delaware River Port Authority and would be used for initial dredge materials. The maintenance dredge would be placed in the 7 federally-owned CDFs.

1. DELAWARE BAY.

 The first dredged material volumes from Reach E, Delaware Bay, contained predominantly sand, and was therefore supposed to be used in the restoration wetland restoration zones i.e. the Egg Island Point and Kelly Island, and for nourishment of beach and Delaware state environmental restoration. The restorations of wetland and as well as nourishment of the beach will aid in controlling the extreme erosion that is taking place at many parts within the shoreline of Delaware Bay.

1. Maintenance Dredging 

From the design, it is projected that the required annual dredge maintenance of the 45 feet deep channel will be increased to 6,008,570 cy/yr from the original 4,900,000 cy/yr for the channel with 40 feet depth. 

Financial cost and sources of funding 

                  Based on preliminary report the project was estimated to cost $208 million which increased to $389 million was be financed by combination of cash on hand, bonds, and user charges. The cost is shared 35% by the Philadelphia Regional Port Authority (PhilaPort), who is non-federal benefactor, and 65% through the U.S. Army Corps of Engineers federal government (Grigalunas 1).

Table 2: Cost breakdown of the projected cost of the project

Feasibility assessment of the project

Currently, the Delaware River Ports is among the biggest ports with freshwater worldwide. The Delaware River Port would be last among the East coast ports to implement channel depth redesigning (Kauffman 1665). The ports such as Baltimore, Norfolk, Savannah, and Wilmington have channels that range between 42 and 50 feet deep.  The general cargo terminals oil refineries and several other cargo establishment with Delaware River have cargo control of over 70 million tons yearly. This regional economic sector is believed to be creating revenues over 3.5 billion US dollars, over $150 million in local and state taxes, over $1 billion in wages, and over 30 thousand job opportunities. Before deepening, the 40-foot Federal Navigation channel of Delaware River could limit effective movement both tankers, container vessels and dry bulk carriers (Kauffman 1665). This situation could be associated with huge operation costs (due to inefficiency), significantly light loading, exclusion of large size and more effective international shipping fleet, and ship delays. It is therefore a realistic prospect that deepening the Delaware River Main channel by extra five feet would revive the competitiveness of the Delaware River Ports. 

As aforementioned, every major port within the East Coast have a luxury of at least 42-foot depth, depth extension for Delaware River would Channel would be critical to commerce of the region and a fundamental tool for unlocking the economy.  The modified channel comes at the time PhilaPort is facing tough rivalry from the neighboring Wilmington Port, who gave a go ahead the leasing plan to an UAE operator, Gultainer and pledged to $600 million purposely to upgrade its container volume from 350 thousand to 1.8 million. On the other hand, Phillaport has a state backing to invest $300 million in bid to upgrade its main container wharf with bigger birth and taller cranes to allow for efficient management of large ships (Larimer 1). Also, New Jersey and Delaware, who are not involved in the funding of the project are in contrary litigating the project, though their terminal within the Delaware River are expected reap huge from the project as they will opened to bigger vessels. 

The project will greatly reduce oil spillage.  Before the tankers would be required to lighten before navigating through the channel. Deepening would allow these tankers to able to navigate straight upriver and unload their whole loads at the dock conveniences for refineries. Thus, any possibility of oil spillage all through a lightening process would be totally eradicated in these tankers. Also, larger tankers, with navigation depths of up to 55 feet approaching the Big Stone Beach Anchorage, would be positively affected. The 45-foot navigation will decrease the total volume necessary to lighten the vessel in the ecologically sensitive lower bay. This will minimize the possible of oil spillage by reducing the both total hookups required and tanker time at the anchorage while the lightening barge fleet.

Environmental impact

Erosion of the Shoreline remain a great threat to the diversity and abundance of the fish and marine life of the Delaware Bay. The environment Agencies evaluated three forms of suggestions by the Corps in material for the dredging operations to battle erosion of the shoreline: restoration of wetlands with geotextile tubing, sand stockpiles, and beach nourishment.  They settle that the planned wetland restoration schemes at Kelly Island and Egg Island Point would benefit to fish and marine life (Hale et al. 1198). They further established that nourishment of beach would have the significant positive impacts on beaches lying between South Bowers and Port Mahon Beach, while beach nourishment in the more southern zones of Shoreline with Delaware River would be less advantageous, yet it is worthwhile. The environment agencies also established that the suggested dredged material disposal in sand stockpiles seems to cause negative impacts to the marine life and fish, they suggest that the usage of sand stockpiles are to be reduced or completely eliminated from the project. 

This constructive use of material would restore 60 acres of coastal wetland and safeguard nearly 5,000 feet of tidal wetland erosion. The 5,000-foot long sand berm, which will include dredged material, will offer environment for the migratory shorebirds (i.e. sanderlings, rough turnstones and red knots) and nesting of horseshoe crabs,. The wetland restored and tidal stream canals would offer shelter for, winter and summer flounders, long-legged wading birds, and migratory shorebirds (i.e. dunlins, dowitchers, and semi-palmed sandpipers). Several beaches and wetlands along the coasts of Delaware Bay are badly degraded (Hale et al. 1198). Dredged material will be put at Port Mahon to rebuild the eroding coastline, safeguard the coastal wetlands around the beaches and improve the habitat for migratory birds and horseshoe crabs. In other regions where areas bordering the beach having structures built, the location of the beach would shield the land against damages from storm.

Conclusion

The objective of the Delaware River Main Channel was to increase the depth of the Delaware River from 40 feet to 45 feet. The project involved dredging and disposing of dredged material, with a portion of it utilized to restore the wetland, ensuring a productive use of the dredged material. Despite facing legal challenges from environmentalists who believed the project would harm marine life, as well as opposition from neighboring states who doubted its impact on the accessibility of the Philadelphia port shipping environment, the project, in the end,  demonstrated substantial positive environmental and economic effects.