B5.9.1 Changes in Erosion at Soliman Beach, Tunisia, after Replacing Breakwaters with Groins

BOX 5.9

Effects of Different Defense Structures in Soliman Beach, Tunisia (Continued)

FIGURE B5.9.1

Changes in Erosion at Soliman Beach, Tunisia, after Replacing Breakwaters with Groins

a. Beach in May 2017, showing transects and shorelines, 2000–20a

Shoreline 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 Transect intersects 1 2 3 4 5 6 7 8 9

Tr ansect distance from baseline (= 2000), meters

5 0 –5 –10 –15 –20 –25 –30 –35 –40 –45 –50

b. Extent of shoreline change, by transect, 2000–20b

2001 2002200420052006200720082009 Transect: 1 2 3 4 5 6 7 8 9

20102011201220132014201520162017201820192020

Source: NOC 2020. Panel a: © World Bank. Further permission required for reuse. a. The photo in panel a shows Soliman Beach as of May 2017, before construction of the groins. b. The bar chart shows cumulative erosion or accretion at different transects in different years relative to the baseline year (2000).

may have quite dissimilar impacts on the processes affecting the coast and beaches. Careful planning is necessary to incorporate possible effects of different structures and to select the ones that have the desired effects once implemented.

Source: Cooperative analysis for this volume with the National Oceanography Centre (NOC) in the UK using high-resolution satellite photos of Soliman Beach in Tunisia.

Soft defenses. Soft-defense solutions have been used in recent decades. Soft solutions include beach nourishment, wind fences, sand dunes, artificial reefs, and other NBS:

• Beach nourishment is the addition of sediments, sand, or both along the shoreline to maintain beach land width and act as a soft-defense mechanism by dissipating wave energy before it reaches the coastline.

This aids shoreline stabilization, improves beach quality, and improves storm protection. Beach nourishment can be costly, affect marine ecosystems, and require a constant supply of new sand.

• Wind fences are structures that act as barriers against winds to accumulate sand and sediments carried by the winds on the downwind side of the fence as an intervention for shoreline stabilization (Khalil 2008).

• Sand dunes are mounds of sand built or maintained to protect the coast from coastal erosion impacts such as exposure to waves and tides.

Dunes act as backshore protection, protect the coast from waves, and can be vegetated so they are not easily eroded.

• Artificial reefs are objects made of environmentally friendly materials placed on the seabed offshore to help retain sediments and dissipate waves while having other environmental impacts such as creating a thriving marine ecosystem (shoreline stabilization).

• Nature-based solutions (NBS) are interventions aimed at safeguarding, sustainably managing, and rehabilitating the ecosystems in addressing societal challenges while benefiting human well-being and biodiversity.

Beach-nourishment projects have been implemented in the Middle East and North Africa and received more attention recently. For example, between 1986 and 1995, five beaches near Alexandria, Egypt, were restored this way. The beaches of El Asafra, El Mandara, El Shatby, Miyami, and Stanley were (re)nourished using sand from the desert near Cairo, with all of these projects meeting or exceeding the expectations for beach restoration (Fanos, Khafagy, and Dean 1995). In an assessment for further protections, beach nourishment under the tenets of an ICZM scheme was considered the most cost-effective measure to combat beach retreat (El-Raey 2009).

In 2014, the United Arab Emirates approved a large-scale project to restore the three Umm Suqeim beaches after they faced severe erosion due to offshore developments. For Umm Suqeim I Beach, installation of five groins and beach nourishment were undertaken, while for the other two, only beach nourishment was used. The works included a total of around 500,000 cubic meters of sand, and around US$9.5 million was

approved to implement the measure in multiple phases (Construction Week 2014; Khaleej Times 2017), which also included a nine-month closing of the beaches (Khaleej Times 2015). Innovative approaches for the effective deployment of beach nourishment practices have been used extensively—for example, in the Netherlands (box 5.10).

BOX 5.10

Building with Nature: Approaches for Beach Replenishment from the Netherlands

In the Netherlands, an innovative nourishment process was adopted, pumping sand and gravel onto the beach during high tide and allowing the coastal process to spread the sand, resulting in the restoration of the dunes and beach (de Schipper et al. 2016). The project, called “Sand Motor,” is located along the narrow Dutch coast between The Hague and Hook of Holland and was constructed in 2011.a The project contains approximately 20 million cubic meters of pumped sand that, in its original form, was placed as a hook-shaped peninsula with a length of 2 kilometers alongshore and extending 1 kilometer into the sea. A series of assessments have found it to be successful in feeding the adjacent coastlines with sediments and aiding beach buildup (de Schipper et al. 2016; Luijendijk et al. 2017; van der Meulen and van der Valk 2019).

The Sand Motor acts as a measure of defense to avoid the erosion of the coast that protects the nearby lands lying below sea level by spreading the sand in a natural way with wind, waves, and currents along the coast. As a result, this peninsula gradually changes its shape, decreasing in size, and over the long term it will fully assimilate with the protected coast. The Sand Motor project is an example not only of beach nourishment but also of an integrated coastal management approach that uses a soft-defense solution, data, monitoring, and analysis along with nature processes and recreation for a comprehensive solution (van der Meulen and van der Valk 2019).

The Spanjaards Dune is part of larger nourishment efforts along the coast (including the Sand Motor project and others) to reduce coastal erosion and ensure coastal safety (van der Meulen et al. 2015). It was constructed in 2008–09 with an original size of around 35 hectares in front of the coast to be protected—the Delfland coast near The Hague—as a compensation for losses of the original dune habitat (van der Meulen and van der Valk 2019). Nourishment through the Spanjaards Dune project required the dredging of 6.5 million cubic meters of sand that was piped to shore from 19 kilometers offshore. Similar to the Sand Motor, natural forces are left free to shape the area further and reinforce dune habitats that need compensation (van der Meulen and van der Valk 2019).

a. For more information, see the Sand Motor website: https://dezandmotor.nl/.

Other soft defenses include the installation of wind fences and artificial reefs. APAL has used several soft measures to combat coastal erosion, including wind fences to trap sand and rebuild dunes. APAL initiated a number of actions, implementing them in a participatory manner involving the local population, while taking into account the ecological, economic, and archeological aspects. These initiatives aim to protect the beaches, with the first three phases of the project costing about €38 million (of which 75 percent was financed with grants and loans from the German government). These initiatives included a series of different structures (for example, submarine breakwaters) as well as installation of over 4 kilometers of pinewood fences to stabilize dunes, which are natural protective barriers (Albrecht-Heider 2020). These protection measures help to withstand erosive forces like waves while having rather few side effects.

A pioneering project in Morocco, although not specifically aiming for protection from coastal erosion, installed artificial reefs in Martil, in the north of the country, in 2012. The project was successful in restoring fish stocks—the main objective—but stabilization of the Martil artificial reef community is a slow and long-term process (El Mdari et al. 2018).

NBS through vegetation and natural coral reef restoration have been increasingly used to retain sediments and restore biodiversity and blue carbon. According to a planning framework by Belize’s Coastal Zone Management Authority and Institute, “Terrestrial protected areas provide erosion and flood control, sediment retention, and carbon storage. Marine protected areas which include coral reef, sea grass and mangrove offer a variety of coastal and marine services such as protection against erosion, reduction of damages from storm surge, and protection from sea-level rise” (CZMAI 2016). The use of vegetation—such as through the creation, conservation (or both) of wetlands and mangrove zones— includes rehabilitation or plantation of seawater vegetation along the shores to retain sediments and to act as a natural defense line by dissipating wave energy. This option traps sediments and prevents coastal erosion while also enhancing biodiversity by restoring habitats for landbased creatures and safe havens for fish in the case of mangroves.

Restoring biodiversity and supporting revegetation with native species is an important aspect of NBS. In the Middle East and North Africa, such efforts have included the Corso Commune coastal dune ecosystem rehabilitation project, east of Algiers in Algeria. In the course of it, the Ecological Association of Boumerdes, with cooperation of local public authorities, took steps to stabilize dunes with the aid of vegetation. The project also included action to support rehabilitation of coastal sites against human action by implementing actions for cleaning and development of these spaces (Canals Ventín and Lázaro Marín 2019).

In the Red Sea and the RSA, mangroves and coral reefs provide protection and contribute to combating coastal erosion in a cost-effective way. When comparing the costs of hard-defense interventions such as tropical breakwater projects with the costs of NBS such as coral reef restoration projects, the cost-effectiveness of such NBS becomes clear. However, mangroves and coral reefs have been under stress in the Middle East and North Africa from climatic changes as well as human interventions. For example, along the coasts of Saudi Arabia, mangrove areas decreased by 75 percent between 1985 and 2013, and reclamation, dredging, and poor fishing practices destroyed coral reefs (MEWA 2017). It is hence important to afforest mangrove forests and restore coral reefs where possible.

Recently, Egypt announced an ambitious project to plant mangroves in the Red Sea Governorate. The project, announced in 2020, represents one of the country’s largest environmental projects and is an effort to combat the effects of coastal erosion and overfishing. More than 200 hectares of land has been set aside for four plant nurseries in the Safaga, Hamata, and Shalateen areas in the Red Sea Governorate and the Nabaq Nature Reserve in South Sinai. Besides mitigating coastal erosion and reviving dwindling fish stocks, the project aims to restore bee populations that feed from mangroves and protect coral reefs (Nile FM 2020). According to officials, the restoration of coral reefs will also help to turn the Red Sea coast into one of the most important destinations for environmentally conscious tourism while protecting beaches from erosion resulting from waves and rising sea levels.

Hybrid defenses. Hybrid defense solutions have been used by combining hard-defense solutions with soft-defense solutions including NBS. These mixtures of solutions allow for a combination of the positive aspects of both solutions—for instance, using gray infrastructure for wave-energy dissipation while also creating natural habitats for species at or near the coasts, such as in mangrove woods and dune vegetation. These combinations also allow for the smoother integration of solutions in landscape planning and enhance policy coherence (Cohen-Shacham et al. 2019). Hybrid solutions can involve several elements such as submerged breakwaters, natural defenses, and dune reinforcement and stabilization through vegetation. (See, for example, figure 3 in Antunes do Carmo [forthcoming].) Typically, not all of the depicted solutions are used together but rather as a combination of two or three solutions.

Hybrid schemes have been used internationally and are suitable for Middle East and North Africa economies. NBS interventions were integrated into the coastal-defense strategy of Medmerry’s coastal-defense management in southeast England (Pearce, Khan, and Lewis 2012). This strategy incorporated ecological engineering at that site, and by

connecting with similar measures aimed at erosion reduction, those NBS interventions had a large impact in reducing coastal erosion along the coast.

In the Middle East and North Africa, Egyptian authorities considered such a hybrid solution for the development of 69 kilometers of sand dunes that are stabilized by a combination of rocks and local vegetation to enhance resilience to climate change in the Nile delta (as discussed in box 5.6). This combination is set to trap blown sand and encourage dune growth. Given that the shores of the Middle East and North Africa region are habitats for some of the most suitable vegetation for coastal protection (for example, mangroves in the Red Sea), a combination of gray and green measures is a suitable option to consider for coastal protection in the region.

Control Policies

Control policies to complement the discussed defensive interventions and to regulate drivers of coastal erosion are important for sustainably managing the coasts. Such control policies aim to mitigate some of the coastalerosion impacts of new and existing development, such as dams and coastal infrastructure (ports, jetties, and so forth). Control policies may also target activities that reduce sediment budgets—activities such as sand mining, which is illegal in most countries but unfortunately still practiced in some, such as Morocco.

The construction and development of dams in relevant zones must be regulated to take into account the influence of dams on the natural transport of sediment to the coast. Rivers frequently get dammed for water supplies, flood control, and hydroelectric power throughout the world, with notable projects in the Middle East and North Africa. North African countries like Algeria, Morocco, and Tunisia, and some Middle East countries like the Islamic Republic of Iran operate a large number of dams. For example, Morocco has 140 large dams with an overall capacity of about 17,600 million cubic meters and more than 100 small dam and hill reservoirs (Loudyi et al. 2018). In the Islamic Republic of Iran, over 600 dam projects have been built since 1979 (Shahi 2019). The Nile Dam between Egypt and Ethiopia, one of the largest projects in recent decades, has led to tensions between countries in the region (Mutahi 2020).

Rivers are important sources of sediments for coastal zones, and modifying them can have distinct consequences on their flows to the coasts (Syvitski et al. 2005). This interception of sediment can then significantly affect erosion processes, as was documented for the Aswan Dam (Masria, Nadaoka, Negm, and Iskander 2015) and the Sebou and Ouerrha Rivers in Morocco (Haida, Snoussi, and Probst 2004). For the Mediterranean Maghreb basin, dams are estimated to reduce sediment

transport by more than 60 percent, with the highest retention rates in Tunisia (72 percent), Algeria (63 percent), and Morocco (55 percent) (Sadaoui et al. 2018). Hence, it is crucial that future projects involving dams be reviewed in this respect. Suitable regulations that address this issue have to be formulated, and ESIAs and EIAs of new projects should include this dimension.

Existing dams could benefit from retrofitting to allow for sediment flow and less accumulation of sediments upstream of the dam. Various methodologies exist to route sediment around dams, through dams, or to relocate sediment trapped in the reservoir to allow for sediment feed downstream and to sustain reservoir capacity (Kondolf et al. 2014). Some techniques to divert sediment around or through a dam are to (a) use off-channel reservoir storage and bypass the dam through a tunnel or a channel (depending on the geometry of the river and steepness for optimizing the design and cost of such intervention); (b) apply sediment sluicing, which is rapidly discharging sediments during periods of high inflows to the reservoir, allowing fine sediments to flow from top of the dam; (c) apply drawdown flushing (the opposite of sediment sluicing, since the gates are at a low level), allowing the resuspension and transportation of sediments downstream. For a detailed review of these options, see Kondolf et al. (2014).

Regulating coastal sand mining and effectively enforcing laws and regulations that ban sand mining in critical zones for sediment balance is crucial in the Middle East and North Africa. As noted earlier, illegal sand mining at the region’s coasts is widespread and has become a serious problem. “Sand mafias” have been established that smuggle sand outside the country, making it a transboundary issue as well as a national and local one (UNEP 2019). Hence, putting an effective ban on illegal sand mining is essential. However, such a ban must go hand-in-hand with a credible enforcement mechanism to ensure compliance. Furthermore, in addition to banning sand mining per se, regulating the use of sand for building purposes and putting in force a strict supervisory mechanism is crucial. For example, in Morocco, half the sand used to build hotels, roads, and other tourism-related infrastructure comes from illegal sources (UNEP 2019). Hence, making a declaration of sources obligatory and introducing hefty fines for noncompliance may be useful in cutting the demand for illegally mined sand.

It is important to start combating coastal erosion by unifying stakeholders’ efforts through an ICZM plan that will not only help combat coastal erosion but also help resolve other challenges such as pollution and biodiversity. All the policies mentioned here are important to control and support effective interventions under the umbrella of ICZM. However, to combat coastal erosion effectively and practically, it is