Who moved my beach?

The beaches of Haifa Bay have been suffering from sand drift in recent years as a result of the construction of marine infrastructure. A new study shows the processes that led to this situation and provides tools for finding solutions in Haifa and the rest of the country

By Alina Bar Yehuda, Angle, Science and Environment News Agency

A new study that examined the changes in the coastal route in the Haifa Bay over the last hundred years, clearly shows that the coastline in the southern part is in constant retreat, due to the massive construction that took place in the southern part of the bay, while in the northern part a trend of expansion of the beach is observed.

Already in 2011, a serious sand drift was diagnosed on the coastal strip in Kiryat Haim, adjacent to the tank farms (crude oil tanks from which the oil is transported to the refineries). To try and deal with the phenomenon, artificial sand feeding was started instead. That is why the research conducted by Naama Sherid, under the direction of Dr. Michael Lazar, who heads the Department of Geo-Marine Sciences at the Leon Charney School of Marine Sciences at the University of Haifa, also examined the effectiveness of the sand feeding, as well as the changes that occurred in the composition of the sand on the fed beach.

The results of the study (supported by the Assaf Shani Foundation for Environmental Studies, the Israeli Center for Mediterranean Research, the Municipality of Haifa and the Israel Mapping Center) paint a disturbing picture of the long-standing process of sand drifting in the south of Haifa Bay, alongside the inefficiency of the sand feeding process. The research was presented at the 2019 Annual Science and Environment Conference.

When a tennis ball meets a concrete wall

Most of the sand on Israel's beaches comes from the delta (estuary) of the Nile River in Egypt. The sand is transported with the help of currents that move eastward to the shores of North Sinai, and further northward to the shores of Israel up to Haifa Bay, which serves as a final trap for the sand. From Acre and to the north, most of the sand is from a different source - weathering of kurkar rocks or oyster fragments.

It was like that for hundreds and thousands of years. But the picture changed during the British mandate, when a deep modern port was established for the first time in Haifa Bay, which required the construction of a breakwater. The breakwater completely changed the sand transport regime in the gulf, because it prevented the entry of sand from the Nile into the southern part of the gulf. 90 years later, a number of buildings were added that also affected the sands of the Gulf, such as the "Carmel" container terminal established in 2010, the Navy port, as part of its construction, a breakwater was erected on the existing breakwater, and the construction of a terminal and breakwater adjacent to the Kiryat Haim beaches as part of the establishment of a "port The Bay" - a new port that is currently being built near Haifa Port, and whose construction is expected to be completed in 2021.

Along with stopping the sand coming from the south, all these actions also greatly increased the drifting of the existing sand on the beaches near the infrastructures. Indeed, through a review of aerial photographs of the coastline from the beginning of the XNUMXth century to the present day, Sherid noticed a trend of the retreat of the coastline in the southern Gulf region, from the "Kan beach" in Kiryat Haim to the port. In the area of ​​the container farms, for example, the drift was so severe that the beach disappeared, which, as mentioned, required restoration by proactive sand feeding.

How does construction on the coastline cause sand drift? To explain this, a relic and a stranger liken the waves of the sea to a tennis ball. A tennis ball thrown hard into the sand will not bounce back, but will stay on it, whereas a ball thrown hard against a concrete wall will bounce off it with power. In the same way, when a wave smashes violently on sand, its energy is dissipated and the wave returns to the sea with less force. On the other hand, when a wave smashes powerfully against a concrete wall, as happens following the construction of buildings and facilities in the bay, it returns powerfully to the sea, sweeping many grains of sand with it.

Right: sand dunes in the south of Haifa Bay in 1918 (photo: Australian military forces), left: the industrial area built on top of the dunes, March 2019 (photo: Naama Sherid)

While the coastal route in the south of the gulf was being eroded by the sea, precisely in its northern part, from the Kiryat Haim area to the horse beach bordering the ancient walls of Acre, a trend of expansion was observed. At first this trend may seem surprising, but after studying the components of the current responsible for transporting the sand within the gulf, Sharid was able to offer an explanation for the phenomenon: "The current that transports the sand from Egypt along the coast of Israel is parallel to the coast, and its main direction is from south to north. However, in the research we discovered that in the northern region of the Gulf there is also a significant current from north to south". Thus, sand originating from the beaches in the northern part of the gulf (and which have not yet been disturbed by construction) is swept into the sea and transported in a current southward to the Kiryat Haim area, and the beaches in the northern part of the gulf are in the process of expansion.

The southern Gulf is outside the influence of this current. When you add to this the fact that the breakwater that borders the bay from the south blocks the arrival of new sand from the Nile, and the local sand reserves that were once abundant are now buried under concrete, the southern shores of Haifa Bay have no ability to rebuild themselves. "If the feeds in Kiryat Haim stop, within a few months there will be no beach left at the container farm," says Sherid. "If this year there were no feeding at the 'Naot' bathing beach, which is located north of the tank farm, then next winter the water would already pass the Sukkat Hamitzil." Sherid, by the way, is careful to emphasize that all the currents in question are not currents that endanger the bathers.

Beaches are sometimes longing for the stream

From Sharid's words it appears that the act of feeding the sands is essential for maintaining the existence of the southern beaches of Haifa Bay. However, she points out that until this year they were carried out without forethought, and so despite the repeated feedings, the beach still underwent drifting of the sand. In addition, the fed sand complies with international standards and is not contaminated, but until this year there was no care to match the fed sand to the original sand on the beach.

As part of the study, several points were sampled on the shore of the container farm, with the aim of seeing if there is a match between the original sand and the supplied sand. The chemical and physical analyzes clearly showed that these are different types of sand. In one of the samples it was even found that the original sand on the site is sand found in estuaries, which agrees with the fact that where the tank farm is today, there used to be the Kishon estuary, which was shifted in the 20s of the last century to another point. However, the sand that was fed was different in color, chemical composition, and physical characteristics.

The fishermen's pier at the "Virgin" beach, Kiryat Yam. Right: You can see the expansion of the beach over the years. Left: According to a local phenomenon of sand accumulation from the north and increased erosion from the south of the "Virgin" pier, the significant current component was identified - from north to south

According to Sherid, the compatibility between the fed sands and the original sands is critical, because any slight change in the chemical composition of the sand, its color or grain size, can be a disturbing factor for the organisms that live on the beach. In addition, the feeding every year created a situation where every year there was a new violation of the ecological environment on the beach. "It's quite ironic: in trying to restore the destruction we created, we caused another change that is not necessarily positive for the original ecological niche," says Sherid.

The results of the research, which will be presented at the 2019 annual conference on science and the environment, have already been presented to the Ministry of Environmental Protection, and according to Sherid, they were received there with an attentive ear. As evidence, in the feeding of the sand carried out earlier this year, there was an effort to import sand from a source that is very similar to the original sand.

In addition to matching the fed sand to the original sand, the research recommendations also include the use of rigid protections, such as geo-tubes (huge sand sleeves) or breakwaters submerged under the water surface, which will help (by dampening the wave energy before it meets the sandy shore) in protecting the fed beaches from Repeated weathering, and in the long run will reduce the need to feed the sand. Also, "in the research, we tried to provide some sort of response to the future construction in Haifa Bay, because if we are already building, then at least it will be done correctly, which takes into account the characteristics of the beaches and the directions of the currents within the bay", she adds.

The public has power

The results of the study, conducted in the Haifa Bay area, have implications at the national level. According to Sherid, any construction that takes place on any of Israel's beaches has a significant impact on the coastal route. "Today it is in Haifa Bay, but tomorrow it could be in Ashdod or Tel Aviv. Therefore, before building a coastal or marine structure, even if it is only a lifeguard pavilion, you need to think about how the structure might affect the beach. If you don't understand the directions of the currents precisely, then any construction may be destructive."

Sherid also emphasizes the power that is in the hands of the public. "If the public is aware of the dangers of building on the beaches, the key role of the dunes and the importance of maintaining them, they can push for the preservation of these beaches."

As an example, she cites the plan to build another marina in Haifa in front of the naval base in Bat Galim. The construction of the marina will not only damage the beach and the unique animals found there, but will also damage the beaches next to it. "If there is an alternative such as docks that are not in use at the existing port, then I call on the public together with the Israel Ports Company and the Haifa Municipality to push for them to use the existing ones and not build anything new."

More of the topic in Hayadan:

• Researchers: It is advisable to make an orderly withdrawal from the coastal areas because of the warming
• The State Comptroller calls for considering the removal of the polluting factories from Haifa Bay
• How is Israel preparing for climate change?
• Unlike most Western countries, Israel does not have an active plan to deal with disasters caused by climate change