Assessment of a Combination Between Hard Structures and Sand Nourishment Eastern of Damietta Harbor Using Numerical Modeling

Alexandria Engineering Journal (2017) xxx, xxx–xxx

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ORIGINAL ARTICLE Assessment of a combination between hard structures and sand nourishment eastern of Damietta harbor using numerical modeling

A.M. Khalifa a,*, M.R. Soliman b,c, A.A. Yassin b a CoRI, Alexandria, Egypt b Faculty of Engineering, Alexandria University, Alexandria, Egypt c College of Engineering, Arab Academy for Science, Technology & Maritime Transport, Egypt

Received 17 December 2016; revised 13 April 2017; accepted 18 April 2017

KEYWORDS Abstract Damietta harbor was constructed in 1982 as an inland harbor with its 15 m depth nav- Numerical modeling; igation channel and two jetties acting like an obstacle to not allow sediment deposition in the har- Damietta harbor; bor. On the other hand, they significantly affect the northern coast shoreline and hinder the Egyptian shoreline changes; sediment circulation in Damietta promontory. Satellite images show that new headlands are being Inland harbor implemented in the coastal shores of As-senaneyah. The proposed project consists of implementation of four headlands with length of 160 m, spacing of 400 m and using 150,000 m3 nourishment in those spacing between the hard structures only once during the construction time. Litpack 1D- model is used to predict shoreline responses to number of different five scenarios considered as combination between hard structures such as headlands and sand nourishment. A total number of 32 profiles were used to assess the shoreline changes along Gamasa, Damietta and Ras El-bar resort from 2010 to 2015. This study prevails a high erosion rate of the eastern and western shorelines of the proposed headlands. Nourishment of 200,000 m3/year is found to be a reasonable solution due to simplicity of being attained from Damietta harbor’s annual dredged materials which was reported to be average of 1 million m3/year. Ó 2017 Faculty of Engineering, Alexandria University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

1. Introduction a new inland harbor of Damietta shown in Fig. 1A [3]. The construction of the harbor, especially its jetties is considered Along northern coasts of Egypt, shoreline changes are found as a sediment trap which hinders natural circulation of sedi- to be high due to harbor construction and shore protection ment along east part of the Nile delta. Sogreah (1982) had pre- structures [1,2]. In 1982, a conclusion was made to construct dicted erosion east of the harbor and is deﬁnite that the effect would be most severe for a distance of 500–1000 m along the shoreline [4]. El.Asmar (2002) results show that signiﬁcant * Corresponding author. E-mail address: [email protected] (A.M. Khalifa). amounts of erosion could be detected using Remote sensing Peer review under responsibility of Faculty of Engineering, Alexandria method for some 6.2 km beyond the eastern jetty, toward the University. coastal resort of Ras El-Bar [5]. El.Asmar (2002) prescribed http://dx.doi.org/10.1016/j.aej.2017.04.009 1110-0168 Ó 2017 Faculty of Engineering, Alexandria University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Figure 1 (A) Layout of study area including Damietta harbor and protection structures and (B) wave gauge station location and wave rose measured in the study area in 2010. that 10.5 km of shoreline would be affected due to the harbor 2. Study area construction [5]. These results indicate that the impact of harbor construction on the Nile Delta shoreline has affected a lar- The study area was assessed by 32 bathymetric profiles surveyed ger area than that predicted by Sogreah (1982) at the time of by CoRI reaching the 8 m depth with average length of 1 km for construction [4]. A retreat of the shoreline is documented five continuous years [10]. Fig. 2 represents the average shoreline about 5 m/year at Ras El-Bar resort [6,7]. Fig. 1A shows the change rate/year through analyzing surveyed shorelines from study area representing 5.5 km western of Damietta harbor 2010 to 2015 with total of 32 profiles distributed on a distance and 9.5 km western of the harbor including the 9 detached of 15 km along Gamasa, Damietta and Ras El-Bar shores. breakwaters and extending to the western jetty of Damietta The data reveal an accretion pattern western of the harbor with promontory which can be assumed as a closed boundary for values range from 10 to 20 m/year over distance of 3 km while an the sediment movement. Ras El-bar nearshore region showed erosive pattern can be determined on the eastern side of the har- continuous deepening of the water depth and steepening of bor with values range from À5toÀ8 m/year over distance of its underwater shore slope. Through the period from 1986 to 3 km. Shoreline bounded with the detached breakwaters can 2000 a series of eight detached breakwaters 200 m in length be observed to have salient phenomenon with an average with 200 m spaces in between were constructed to protect the advancing shoreline of 4 m/year [10]. western side of Damietta promontory along a distance of Wave data in 2010 for a full year were recorded by a current 3km[8]. Salient has already been noticed along the shores of and wave gauge S4DW deployed near the bottom (0.5 m above Ras El-Bar; however, erosion pattern was highly perceived sea bottom) at the western side of the navigation channel of the for the distance of 4 km bounded by the detached breakwaters harbor at a water depth of 12 m and the wave rose was con- in the east and the eastern jetty of Damietta harbor in the west. cluded as shown in Fig. 1B. The wave rose shows that Maxi- Ongoing research pursues using Numerical modeling simu- mum wave height during the strongest storms is almost lations for this classic case of erosion caused by artificial 6.0 m, while significant wave height is 4.2 m from N (January human interference responding to littoral obstacle in the exis- 2010). Wave period is 8 sec for 98.2% of the time (60.4% of tence of natural longshore sediment transport. Thus, this paper the time between 7 and 8 sec). The monthly maximum peak presents a methodology to assess and evaluate number of com- wave period fluctuates between 7.0 and 13.2 sec. The predom- binations between nourishments along with hard structures inant wave direction throughout is from the N-NW (86%) using numerical modeling [9].

Figure 2 Average shoreline changing rates per year.

Figure 3 Litpack 1D-Model setup. sector for all months (mainly from NNW (49%) direction). A Full year wave data of 2010 and measured tidal data were used signiﬁcant spread of wave energy occurs for western waves to simulate the natural coastal condition in the study area. The (NNW, NW and WNW) at about 25–35 km east of Damietta model covers the study area and extends 6 km east from Dami- promontory mouth as discussed by A.Abo ZED [11]. etta harbor and 9 km to the west reaching the western jetty of Damietta promontory which considered the eastern boundary 3. Numerical model development of the model. Fig. 3 presents the study area with the included structures as breakwaters, Damietta seawall, two harbor jetties Litpack [12] 1D-Model was applied to simulate shoreline and two groins in the west of the seawall. Measured 2014 changing in the study area to assess the combination between shoreline was used as the initial condition of the model. The hard structures and nourishment in order to solve the problem harbor’s jetties were deﬁned as two jetties with perpendicular of obvious erosion in the beaches eastern of Damietta harbor. alignment with the baseline which is assumed to be horizontal

Figure 4 Calibration process dividing the model domain into three parts 5000 m for each shown as (A) represents first 5 km, (B) represents second 5 km and (C) represents last 5 km of the model. as simplified as shown in the figure. Eight profiles were used to surveyed 2014 shoreline [10] as an initial shoreline and 2015 simulate the varieties in bathymetry along the study area. shoreline [10] which is compared with the model predicted shoreline. The used calibration parameters are active depth 4. Preliminary results which defines closure depth in the study area assumed to be 12 m along the study area, extension of the sediment transport 4.1. Model calibration table (the distance from actual shoreline to the surf zone which is significant when a coastline is protected by short groins that do not extend across the surf zone) is tuned to be 70 m and Shoreline change in the study area is simulated during the year diffraction spreading factor (The wave diffraction spreading from 2014 to 2015. Model calibration was implemented using

Figure 5 Scenario 1 shoreline prediction in 2034 divided into three parts 5000 m for each shown as (A) represents first 5 km, (B) represents second 5 km and (C) represents last 4.5 km of the model. factor describes the wave concentration parameter in deep with various rates changing from 10 m/year to 20 m/year while water) was taken as 25. The final calibration can be done by erosion behavior is also predicted eastern of the harbor with altering the active depth in the coastline file or by modifying various rates changing from À5 m/year to À10 m/year. The the extension of the sediment transport tables. The model is last mentioned rates are totally comparable to rates concluded calibrated when the simulated coastline evolution fits with from measured data through years of 2010–2015 reported by the measured one [12]. Fig. 4 shows the Calibration results CoRI as shown in Fig. 2. In addition, the salient patterns using observed shoreline of 2015. The model significantly are well simulated behind the detached breakwaters of Ras could predict the severe accretion rate western of the harbor El-Bar resort. The model results showed a standard deviation

Figure 6 Scenario 2 shoreline prediction in 2034 divided into three parts 5000 m for each shown as (A) represents ﬁrst 5 km, (B) represents second 5 km and (C) represents last 5 km of the model. of 6.5 m for error which is a reasonable result for a 1D-Model. terms of water level and littoral drift due to hourly incident Comparing the model simulated shoreline change rates with waves between January 2014 and January 2034. observed data, the model is obviously found to be completely satisfactory and equivalent to the present situation of the shoreline changing phenomenon in the study area. 4.1.1. Scenario (1): Benchmark (the current case without new After the model calibration, the model is used to simulate protection structures) results of the present situation of the shoreline with existing The study area was divided into three parts by a distance of structures and to predict the effect of multiple scenarios in 5000 m per part. Fig. 5A shows the ﬁrst 5000 m of the model,

Figure 7 Scenario 3 shoreline prediction in 2034 divided into three parts 5000 m for each shown as (A) represents ﬁrst 5 km, (B) represents second 5 km and (C) represents last 5 km of the model. and various shoreline changes patterns are detected. Huge 4.1.2. Scenario (2): Usage of 200,000 m3 nourishment/ year amounts of sedimentation in front of western jetty of Damietta Fig. 6 illustrates the case of using continuous annual nourish- harbor (about 480 m) by 2034 while in the eastern side of the ment process divided into two sections on the shore, harbor erosion pattern with maximum of À180 m/20 years will 150,000 m3 distributed on 740 m from 7500 m to 8240 m mea- be formed as shown in Fig. 5B. Fig. 5C presents the last sured from the reference line of the model and 50,000 m3 dis- 4500 m to the end of the study area including the detached tributed on 240 m from 10000 m to 10,240 m measured from breakwaters and seawall shores. Salient formation is very clear the reference line of the model. Fig. 6B reveals the same huge to be noticed and Ras El-Bar that is protected by breakwaters amounts of sedimentation in front of western jetty of Damietta is totally stable.

Figure 8 Scenario 4 shoreline prediction in 2034 divided into three parts 5000 m for each shown as (A) represents ﬁrst 5 km, (B) represents second 5 km and (C) represents last 5 km of the model.

harbor 480 m by 2034. On the other hand, in the eastern side of bor’s navigation channel which was reported to be 1 mil- the harbor nourished area was totally stabilized changing from lion m3/year [13]. À180 m/20 years to almost zero. Fig. 6C shows that nourished area was completely alleviated and new beach is starting to be 4.1.3. Scenario (3): Construction of four headlands with created with rate of 50 m/20 years for Ras El-Bar resorts. nourishment in between Nourishment materials can be easily obtained through the Satellite images show that new groins are being implemented dredged materials from annually obtained from Damietta har- in the coastal shores eastern of the harbor to stabilize the

Figure 9 Scenario 5 shoreline prediction in 2034 divided into three parts 5000 m for each shown as (A) represents ﬁrst 5 km, (B) represents second 5 km and (C) represents last 5 km of the model.

eroded shoreline which was affected by the construction of the hard structures only once during the construction time. Damietta harbor’s two jetties that hinder the natural sedi- Fig. 7B and C shows erosion pattern with average of ment rate from approaching and alleviating the shore of À150 m/20 years for length of 2000 m eastern to the harbor. As-senaneyah. By investigating the project details and con- In addition, high stability between proposed groins is tacting the designers, the project consists of implementation occurred due to high amount of nourishment in a distance of four headlands with length of 160 m, spacing of 400 m of 1000 m. Finally, east to the four headlands for a distance and using 150,000 m3 nourishment in those spacing between of 750 m as average erosion rate of À150 m/20 years was

Please cite this article in press as: A.M. Khalifa et al., Assessment of a combination between hard structures and sand nourishment eastern of Damietta harbor using numerical modeling, Alexandria Eng. J. (2017), http://dx.doi.org/10.1016/j.aej.2017.04.009 10 A.M. Khalifa et al. noticed which was found to be disastrous for As-senaneyah of 200,000 m3 during construction in the downstream of the beaches. headlands. Comparing the five scenarios, the first scenario shows a 4.1.4. Scenario (4): Construction of four headlands with annual high erosion rates eastern of the harbor while the second one nourishment is described as using of annual nourishment to stabilize the Scenario (4) is assumed to be same as scenario (3) with addi- eroded shoreline is found to be unrealistic due to present pro- tional modification of annual nourishment distributed in two posed project launch; moreover, present proposed project isn’t places, 100,000 m3/year along 520 m from 7520 m to 8040 m a well promising one due to high erosion rates. Usage of mod- measured from the reference line of the model and ified nourishment quantities with the present proposed project 150,000 m3 /year along 400 m 9780 m to 10,180 m measured as reported in scenario 4 is found to be the best solution com- from the reference line of the model. Fig. 8B and C shows pared with construction of eleven headlands described to be adjustment of nourishment usage along the two eroded areas unadaptable to the sea’s environmental hydrodynamics, due with thoroughly stabled shoreline. Total amount of to its high cost of construction and high erosion rates occurred 100,000 m3 through construction of the headlands in addition eastern of the eleventh headland. to annual amount of 200,000 m3/year is found to be reasonable and easy to be obtained from the annual dredged materials Acknowledgments from Damietta harbor navigation channel which is reported to be about 1 million m3/year [13]. The authors acknowledge the support given by Coastal Research Institute (CoRI) for this study under the CoRI pro- 4.1.5. Scenario (5): Construction of eleven headlands with ject of studying the effect of coastal structures on Nile delta’s onetime downstream nourishment coasts. Sincere thanks are due to all the staff members of the institute who cooperated in the procurement of the data. Spe- Eleven headlands are proposed to be constructed as an exten- cial thanks are due to Prof. Mohamed Ahmed Soliman (Direc- sion of the present proposed project with 160 m length and tor of Coastal Research Institute) for his great support, 400 m in between spacing. Fig. 9B and C presents simulation allowance on required data gathering and reports reviewing. of the headlands which can be very suitable solution in addi- Sincere thanks are due to Dr. Walid Reda (Head of Coastal tion to 200,000 m3 through construction on the distance of Engineering department, CoRI, Alexandria) for his support 200 m from 10,700 m to 10,900 m measured from the reference and help while data gathering. line of the model. Shoreline can be noted to be stable after twenty years of simulation. However, hard structures are not recommended due to high construction cost, being unadapt- References able with the sea’s environmental hydrodynamics and increas- ing the erosion rates in front of the eastern two detached [1] M. Fanos, O. Frihy, A. Khafagy, P. Komar, Processes of breakwaters to be À100 m/20 years compared with bench- shoreline changes along the Nile delta coast of Egypt, in: Coastal mark’s rate of À50 m/20 years. Sediments Conference, Washington, 1991. [2] K. Sarma, Siltation and Coastal Erosion at Shoreline Harbours, 5. Summery and conclusion in: 8th International Conference on Asian and Pacific Coasts (APAC 2015), 2015. [3] UNESCO/UNDP, Coastal Protection Studies. Final Technical Litpack 1D-Model was applied for a distance of 15 km to eval- Report, Paris, 1978. uate the effect of a combination of headlands and nourishment [4] M. Sogreah, Effects on the construction of the Port of Damietta in order to solve the problem of noticeable erosion in the east- on the evolution of the littoral drift, 1982. ern beaches of Damietta harbor. The model results are cali- [5] H.M. El-asmar, K. White, Changes in coastal sediment brated using the surveyed shoreline of 2015. transport processes due to construction of New Damietta Five scenarios were namely as follows: the first scenario is Harbour, Nile Delta Egypt, Coast. Eng. 46 (2002) 127–138. prescribed as the present situation without any additional pro- [6] O. Frihy, A. Fanos, A. Khafagy, P. Komar, Patterns of nearshore sediment transport along the Nile Delta, Egypt, tection structures while the second scenario represents using 3 Coast. Eng. 15 (1991) 409–429. 200,000 m /year in two different positions on the eastern side [7] M. Fanos, The impact of human activities on the erosion and of Damietta harbor. The third scenario simulates the proposal accretion of the Nile Delta coast, J. Coast. Res. 11 (1995) 821– of constructing four headlands with length of 160 m, spacing 833. 3 of 400 m and using 150,000 m nourishment in those spacing [8] D.M. Saleh, Impact of storm waves on the nile delta coast PhD, between the hard structures only at the construction time. Alexandria University Faculty of Engineering, Alexandria, The fourth scenario prescribes a modification of scenario 2015. two due to high erosion impacts upstream and downstream [9] H. M. El-asmar, K. White, Rapid updating of maps of dynamic the headlands by using total nourishment of 200,000 m3/year coastal landforms by segmentation of Thematic Mapper with 150,000 m3 through construction of the headlands. This imagery, example from the Nile Delta, Egypt, in: 23rd Annual Conference of the Remote Sensing Society, Nottingham, 1997. scenario was found to be reasonable due to simplicity of [10] C. R. Institute, Studying Shoreline Changes along Ras El Bar bypassing nourishments from Damietta harbor’s navigation Coastal Zone, Nile Delta Coast during the period (2005–2014), channel dredged volumes which was reported to be average Alexandria, 2014. 3 of 1 million m /year. The fifth scenario consists of using eleven [11] A.b.E. Abo zed, Effects of waves and currents on the siltation headlands as an extension of the present project with 160 m problem of Damietta harbour, Nile Delta coast, Egypt, length and 400 m inner spacing in addition to nourishment Mediterr. Mar. Sci. 8 (2007) 33–47.

[12] DHI, dhigroup, DHI, 2016. [Online]. Available: (accessed 2016). Nile Delta to Climatic Change and Sea Level Rise through [13] E. Ibrahim, M. Wahid, E. Omran, E. Essam, A.-E. Essam, ICZM Project, Alexandria, 2015. Economic Feasibility Assessment of Using Dredged Material