Egyptian Coastal Lakes and Wetlands: Part I

Egyptian coastal lakes are valuable sources of wealth and sensitive environments. Egypt has two forms of coastal lakes, deltaic lakes such as Mariout, Edku, Burullus, and Manzala and non-deltaic lakes such as Lake Bardawil. Ramsar Convention recognized Burullus and Bardawil lakes as important wetlands, which are located in the Egyptian Mediterranean coastal area. These lakes with some attention could financially support the Egyptian government as being an economical source of huge fishing industry. Also, it could be a valuable source of jobs and food. Currently, it provides 40% of the harvested fish, and it is expected to be increased after completing the ambition new Egyptian development project. In 2017, the first phase of the largest fish farm in the Middle East is materializing on the international coastal road in the Berket Ghalioun area in the Metoubas locality, in Kafr al-Sheikh governorate (State). This project is to be built on an area spanning 2,750 feddan, costing LE 1.7 billion. Also, these valuable resources got the attention of the Egyptian government. The Egyptian Ministry of Environmental Affairs (MEnA) updated the National Biodiversity Strategy and Action Plan (NBSAP) for the years 2015–2030. The main goal of the new strategy is reducing the rate of wetlands loss by 50%. The Egyptian coastal lakes suffer major problems, such as degradation; habitat loss; pollution as they receive great amounts of industrial, municipal, and agricultural wastewater without treatment; and the spread of aquatic plants. Moreover, the illegal fishing practices and illegal harvesting of fish, the blockage of Boughazes, and the low awareness of fishermen are other types of challenges to be solved. Although two lakes, Burullus and Bardawil lakes, have got the attention of the government, Edku and Mariout lakes still in urgent need for an action plan toward sustainable development. An initial step toward better lake management is presented in the following chapters as it will address the lakes’ current situation and discuss how to sustain it.

Coastal lakes in Egypt are very important for the wetlands they support in North Africa. They contain five of the most productive wetland ecosystems in the world. The Nile Delta lakes, which are located along the Mediterranean coast, are very important economically because of fish production, which makes up nearly 50% of Egypt’s production. These lakes are vital to the livelihoods in these areas. However, these lakes are suffering from degradation and environmental stress. The total area of many of these lakes is decreased because of drying and reclamation for agriculture. Furthermore, increased pollution and ecological risks are affecting these vital and valuable lakes. One of the biggest issues is the discharging of agricultural drainage, industrial waste, and domestic waste water into these wetlands. In addition, these lakes are vulnerable to the negative impacts of climate change such as rising sea level and saltwater intrusion. The coastal lakes in Egypt are very important and vital to ecosystems and need continuous monitoring and good management practices.

Coastal lakes can have a significant impact on the surrounding agricultural areas through waterlogging, secondary salinization, and groundwater pollution. In this chapter, the authors will provide an overview of the coastal lakes in Egypt, the main challenges, and how to manage these challenges for the sustainability of these lakes.

Lakes are one of the most important characteristics of Egypt’s coastal areas. However, deteriorating condition of these lakes due to industrialization, land reclamation, agricultural practices, overfishing, bird hunting, and coastal erosion is serious. Many challenges are faced by these lakes, some of which are the most polluted lakes in Egypt where they receive large quantities of agricultural, industrial, and municipal wastes through several drains and from factories around them. In addition, Egypt’s Mediterranean coast and the Nile Delta have been identified highly vulnerable to climate change impacts. Adaptive management is the best approach for addressing this type of complex problem. The main objective of this chapter is to classify Egypt’s lakes and depressions and to evaluate the land resources status of Egypt’s coastal lakes. Also, the challenges facing the sustainable development of these lakes were identified. Adaptive management approach would facilitate the investigation and classification of Egypt’s lakes and depressions.

Egypt has been distinguished into four adaptive management zones based on different factors such as the climatic conditions in combination with the agriculture, physiography, natural resources, and other issues affecting the socioeconomic activities. The country is endowed with four main zones as follows:

In the northern lakes, the levels of pollution in these lakes are Mariut > Manzala > Edku > Borollus > Bardawil. The most polluted lakes are Lake Mariut and Lake Manzala. Lake Mariut receives agricultural drainage and domestic and industrial wastewater from agricultural drains. However, Lake Manzala serves as a final repository for many of the municipal and agricultural wastewater of the eastern Delta, including the wastewater of most of Cairo. The main contributors to the lake are the Bahr El-Baqar drain, Hadous drain, and drainage water delivered by Mataria, lower Serw, and Faraskour pumping stations. Bahr El-Baqar drain carries sewage effluent from Cairo and the drainage water of more than 200,000 ha of agricultural lands.

The result of the case study on the Lake Manzala showed the land use and land cover change that has occurred during the period 1986–2016. The highest positive changes areas are showed in crop vegetation areas (+16.44%) and bare land areas (+15.43%), while the highest negative changes areas are displayed in natural vegetation areas (−23.91%) and fish pond areas (−10.77%).

Mariout, Edku, Burullus, El-Manzala, and Bardawil lakes are the five northern lakes connected to the Mediterranean Sea. They suffer from different types of serious problems because they receive contaminants from drains. Consequently, those lakes are under increasing threat from eutrophication, pollution, and destruction of surrounding wetlands. Sediments of lakes deposit small particles because of the relatively unmoving waters in them. Sediments in these lakes are considered to be the sink of these different contaminants. The inorganic contaminants like heavy metals had been determined in the sediments of the lakes. The organic contaminants like polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) are found to bind strongly to sediments. In Lake El-Manzala, Hg showed the highest values and alarming toxicity levels, and it is considered as one of the most hazardous. Lakes Burullus, Edku, and Bardawil recorded highest values of some heavy metals, while Lake Mariout got the highest ranged values for the organic contaminants. Continuing observing and monitoring of northern lakes is very important to resolve the existing contamination problems and to avoid its complication in the future.

Egypt’s coastal wetlands are located along the Mediterranean coast; four in the northern part of the Nile Delta (Manzala, Burullus, Mariout and Edko) and one in the northern part of the Sinai (Bardawil). According to the map of the world distribution of arid areas, northern Egypt belongs to the Mediterranean arid region. The climatic conditions are warm summer (20–30°C) and mild winter (10–20°C). The aridity index ranges between 0.03 and 0.2 in the northern areas and less than 0.03 in the south (hyperarid region).

In the Delta wetlands, the annual mean water temperature is 22.3°C, while the annual mean water transparency and water depths are 31.0 and 115.8 cm respectively. The annual mean water chlorosity is 1.9 g l⁻¹, while in Bardawil salinity ranges between 38.5 and 74.5‰. Water in these wetlands is alkaline throughout the year. The annual mean pH is 8.6. On the other hand, the annual mean alkalinity was 257.8 mg l⁻¹.

The annual mean dissolved oxygen (DO), chemical (COD) and biological (BOD) oxygen demands are 8.6, 4.6 and 3.6 mg l⁻¹, respectively. The concentrations of dissolved salts have the following sequence: SiO₂ > NO₃ > PO₄ > NO₂, with annual means of 41.7, 2.8, 1.2 and 1.1 μg-at. l⁻¹. The concentrations of heavy metals have the following sequence: Zn > Fe > Cu > Cd > Pb, with annual means of 8.5, 6.2, 5.9, 3.8 and 3.6 μg-at. l⁻¹. Most of the estimated heavy metals of the water near to the southern shores were higher than those near the northern shores due to pollutants of drainage water. The comparison of the dissolved salts in the water of Delta wetlands in 2015, with those of the 1980s, indicates a tremendous increase due to an increases of agricultural drainage waters that are rich in fertilizers and discharge into these wetlands from the southern drains.

This chapter presents an extensive background on Lake Manzala, Egypt, in the form of a literature review. It covers the lake’s physical, chemical, and biological characteristics to date. In addition, the main challenges for the lake water body are land reclamation, nutrient enrichment, and pollution, especially from the Bahr El-Baqar drain. In addition, the spread of aquatic plants, such as water hyacinth, has occurred in most parts of the lake, which affects the movement of water in the lake, and hence the quality of both water and fish health. A summary of relevant research that has been conducted during the past four decades are presented. These investigations include a wide range of research investigations that have considered the chemical, physical, geological, and biological facets of the lake. In addition, the numerical models and recent studies from the literature are presented. It is concluded that a quick action for the lake remediation is initially to allow the law to take action over any type of stakeholder’s violence toward the lake. A socioeconomic study for Lake Manzala is recommended. Moreover, increased numerical modeling would provide further benefit.

The northern lakes, particularly the delta ones (Manzala, Burullus, Edku and Mariout), were among the richest and most diverse ecosystems in Egypt 40 years ago. They are the important natural resource of fish production in Egypt. Besides, they are internationally important sites for the migrating birds, providing them with the suitable habitat. Water discharges into the lakes are mainly agricultural drainage water (containing pesticides, fertilizers) and effluents of industrial activities and runoffs. In addition, sewage effluents supply the lake water body and sediment with huge quantities of inorganic anions (such as phosphates, nitrates and ammonia), combined organic nitrogen and heavy metals. Such nutrient enrichment to the lakes’ ecosystem is mostly followed by alterations in phytoplankton community structure. The phytoplankton represents the main group of primary producers and hence is considered as the main food source for fish in these lakes. In addition to the four mentioned delta lakes, Lake Bardawil is located North Sinai, and it is a saline lake which is considered one of the most important lakes in North Egypt. Lake Bardawil environment differs from that of the other Mediterranean Egyptian lakes in terms of climatic factors, geomorphology and salinity. The northern lakes provide a rich and vital habitat for estuarine and have always been major areas of fish production in Egypt, where they contribute to the economy of Egypt. The alteration in environmental conditions together with other human-induced pressures and interferences has played an important role in lake deterioration and water quality and accelerates all the biological productivity along the lakes. In nature, thousands of years are required for oligotrophic water body to become an eutrophic one. Water quality of the northern lakes is largely influencing phytoplankton growth, the structure of their community and the trend of species succession. Therefore, the pattern processes and dynamics of phytoplankton community assembly along the five lakes should be studied in order to understand the status of the water quality of the lakes. For example, Lake Edku was classified among the oligotrophic lakes several years ago because it receives huge amounts of drainage water; however, it is currently described as eutrophic lake with a tendency to hypertrophy. In this chapter, we discuss the phytoplankton ecology along the Egyptian northern lakes with special reference to status, pressures and impacts.

Different studies have revealed that Egypt’s coastal wetlands have become more dulcitude, eutrophic, and productive ecosystems, owing to remarkable increase in amount of discharging agricultural drainage, loaded with nutrients, into the wetlands via the southern drains. Decreasing salinity and nutrients loading have led to significant impacts on biodiversity and abundance of macrobenthos in these wetlands, such as in Burullus. Thirty-four macrobenthic species, belonging to three main groups (Arthropoda, Annelida, and Mollusca) were recorded in this wetland during 2013. There was no sign of occurrence of eight marine species, which have been previously recorded in this ecosystem during the 1970s and 1980s of the last century. It is worth mentioning that 17 species (freshwater in origin) were recorded for the first time in the Burullus wetland during 2003.

On the other hand, the macrobenthic community in the saline Bardawil Wetland during the last decade hosted 51 species belonging to five phyla: Arthropoda, Annelida, Mollusca, Echinodermata, and Coelenterata. The abundance of macrobenthic species was closely correlated with the nature of bottom sediments, organic matter, and salinity. The long-term changes in the macrobenthos density of the Bardawil Wetland were attributed to changes in the fish community structure.

This chapter is split into two broad sections. The first deals with lakes – more specifically their categorization, their characteristics, and the quality of their water. The chapter briefly presents the seven main different formation processes, as tectonic activity, volcanic activity, glacial activity, fluvial action, Aeolic action, anthropogenic action, and marine action. The lakes are characterized by low flow velocity and relatively low inflows and outflows. Vertical stratification appears in deep lakes, while shallow lakes are considered well mixed in the vertical axis. Lakes act as a sink for all types of nutrients, toxins, and all organic suspended materials from different types of sources. The second section focuses on the hydrodynamics within lakes, dealing with the very specific nature of flow that is peculiar to these large bodies of what often appears to be still water. The main hydrodynamic processes in lakes are inflows and outflows, wind shear, vertical circulation, thermal stratification, and gyres and seiches.

This chapter presents a review of previous studies related to the numerical modelling of the hydrodynamics of coastal lakes with emphasis on Egyptian coastal lakes. Also, related applications, such as water quality management and sediment transport scenarios in lakes, are presented. The focus is primarily on existing, well-established, numerical models and their applications to shallow water systems. The chapter starts with a general introduction to lake modelling followed by the techniques and assumptions that are commonly used. A summary of the available hydrodynamic models categorised based on whether they are one-, two-, or three-dimensional is presented. Previous hydrodynamic modelling of lakes is reviewed under a separate section within this chapter as well as those studies related to water quality management.

Egyptian coastal lakes, which represent about 25% of the Mediterranean total wetlands, are not only one of the most valuable ecosystems in the world but also some of the most threatened as they receive the wastewater discharged from the watershed. Lake Mariout was one of the most important shallow coastal lakes north of the Nile Delta of Egypt that produces between 50 and 70% of the total fish production of the coastal lakes, but it was widely used to drain industrial wastes, sewage, and agriculture drainage. As a consequence of the environmental degradation, it has changed from being the most productive fishery resource of the four major Egyptian brackish water lakes to the least productive in a couple of decades. Over the past few years, water quality and hydrodynamic modeling of lakes, lagoons, and rivers has become an important tool for managing water resources, especially in modeling the dispersion of pollutants. The objective of the study is to build a hydrodynamic and water quality model of Lake Mariout, to show the current status of the lake which is subject to pollution from the agricultural drains and the point sources discharging directly to the lake. That objective is achieved through simulating the flow circulation inside the main basin of the lake and the transport and advection of the pollutants and then identifies and develops the most critical surface drainage water quality indicators to simulate and predict the temporal and spatial variation of pollution. The model proved to be an effective tool for the water dynamics, water quality simulation, and evaluating different scenarios of such shallow lake.

Lake Bardawil is an important hypersaline lake located in Egypt on the coast of the Sini Peninsula adjacent to the Mediterranean Sea. The lake is host to several industries which provide critical contributions to the regional economy including farmed and wild-caught fisheries and salt extraction. The lake also has significant ecological importance, serving as a rest stop and overwintering location for a numerous waterfowl. To date, only limited studies of circulation and water properties have been performed leaving lake managers without the information needed to make strategic decisions needed to mitigate long-term threats to the lake stemming from regional infrastructure projects, expansion of industry, and natural processes such as inlet shoaling. The present chapter presents a numerical model of Lake Bardawil which can be used to study dynamic processes and predict the outcome of management actions. The approach predicts the three-dimensional circulation using an unstructured grid approach which enables resolution of the complex coastline and wide range of spatial scales associated with the lake. In a validation study, the model was found to reproduce the annual variation and magnitude of monthly averaged salinity at ten measurement stations but significantly overpredict salinity at the two stations in the shallow far western section of the lake. The model demonstrates that evaporation, wind forcing, and tidal exchanges all play important roles in lake forcing. The present work represents a critical step toward the longer-term goal of establishing an operational circulation model for Lake Bardawil which can be employed as a tool by managers to assist and accelerate the decision-making process.

This chapter aims to provide a summary of the major conclusions and recommendations presented in this volume. It provides a brief conclusion and recommendations for lakes’ better management. Also, it contains some findings from the few recently published work related to the Egyptian coastal lakes. The chapter contains the main background of the Egyptian coastal northern lakes’ physical, chemical, and biological properties. These lakes include Bardawil, Manzala, Burullus, Edku, and Mariout. Moreover, a set of recommendations for future research work is extracted to direct the researcher community toward sustainability of the lake’s ecosystem.