Ecological Lithodynamic Problems Of Managing Evpatoria Littoral Zone And Looking For A Solution
Ecological lithodynamic problems of managing Evpatoria littoral zone and looking for a solution
V.P. Zizak1 N.D. Stephan2, V.V. Belyaev3, V.D. Karachintsev4
1PCF «Projecthydrostroy», Odessa
2Chernomorniiproject, Odessa
3ZAO «Morstroyproject», Sevastopol
A lot of most important biogeosphere processes of the World ocean and land interaction are going on in the contact littoral zone. This zone of high energies is under a constant threat of ecological catastrophes and dangerous geological processes. High population density and its active economic exploitation make the situation even worse. Actually the littoral zone makes up only 5 percent of land. Nevertheless it is a home of 70 percent of the planet’s population. This figure is expected to grow up to 80 percent by the year 2020.
The Crimean coast is by no means an exception in this sense. It suffers from rather active geological destructive processes. The same is true about Evpatoria resort. The beaches in the city centre have been washed out. Waves destroy embankments, houses and other constructions. The preventive measures taken by the local government turned out to be ineffective. Moreover, in many cases they aggravated the situation.
Although the coast of the Calamity Bay (including the Evpatoria Bay) has been studied for a rather long time and the negative consequences of human economic activities are well known, the optimum solution has not yet been found. The reason for these failures is, most probably, the consideration of the separate elements of the problem without paying due attention to the whole complex of the phenomena that affect the condition of the coast. In other words, there has not been a complex approach when making planning decisions.
The coast line, the lithodynamics, hydrodynamics and geomorphology of which determine the direction and the intensity of Evpatoria beach zone changes, stretches over more than 80 km (more than 50 km from Lukull Cape to Evpatoria and more than 30 km from Evpatoria to Donuzlav Lake).
In the area that is so stretched and heterogeneous in the geomorphological sense the process of washing out, transference and
accumulation of alluvia is rather complicated. For that reason, even major quantitative coast parameters that are necessary for making a decision have not been estimated in the same way, although there exist a number of research papers compiled by different researchers and institutions.
In this paper we have made an attempt to apply a complex approach when carrying out theoretical research and planning work in order to choose the optimum way of reconstructing the destroyed sections of the coastal zone and increasing the stability of the lithodynamic system of the whole region, and also to predict the behaviour of the system in course of time. For this reason at the beginning stage of the works there has been built a structural-functional model of the coast line system. As the system is complicated, it includes the systems of the lower level as its constituents – the benthal ecosystem, hydrodynamic, lithodynamic and socioeconomic systems. In our case the lithodynamic system is determinative. The others are interpreted as «the environment». They supply the system’s “entry” with natural and man-caused flows of energy, information and substance.
The lithodynamic system is studied at the regional (Lukull Cape – Evpatoria city – Donuzlav Lake) and the local (Evpatoria Bay) levels.
The structure of this system (like the structure of any other system) consists of three subsystems – management, supply and major means (see Picture 1). The natural structures of supply means (the relief, morphology and configuration of the coastal zone) transform, accumulate and increase the quality of energy and substance flows under the influence of managing information. It is done in a way to optimize the profile of the underwater coast slope and to get a stable accumulative surface formation – a beach of a given size and with rather high recreation qualities.
The system works in accordance with energy laws (under the conditions of entropy decrease in particular) that are sometimes defined as the principle of energy maximization. The most stable are those systems that consume most energy and use it in the most effective way [2].
That is the principle that is applied when carrying out planning and research works, in which the peculiarities of lithodynamic system functioning are taken into account. This kind of approach is called bionic. It helps to minimize costs of hydroengineering and other construction works in the coastal zone. For instance, it is widely recognized that nothing protects the coast from destruction better than beaches. It is also planned to use deforming coast-protecting structures that interact with waves in a certain way.
The researchers of the Evpatoria problem (OGU, Chernomorniiproject, Lenmorniiproject, Krymgeologia and others) are almost all unanimous about the causes of the washing-out of the city beaches. These are sea port construction, local coast protecting, water intake and other structures that have deformed natural lithodynamic processes in the region. It is stated that at present the beaches in the shallow part of the Evpatoria Bay are practically not supplied with new alluvia. That is why it is necessary to take serious management decisions.
However before making a decision we need to:
1. get reliable data concerning the alluvia dynamics and balance because the available data are contradictory and insufficient.
2. estimate the contribution that the alluvia of biogenic origin make to their overall balance.
3. study the effect that port and coast-protecting structures and also coast configuration have on wave processes and currants that they generate in the littoral zone.
4. make a long-term forecast of the littoral zone system’s behaviour taking into consideration the global changes of the sea level and anthroposphere, and also man-caused effect on the region.
To fulfill the first task we need to carry out a great number of research works. And to do this we need to have modern equipment. Only in this case we can gain as much of the lacking information as it is necessary for thorough analysis of the system. These works have been started and are being successfully carried out.
As far as the second task is concerned, there have been research and analysis of the benthal ecosystem carried out at the global (north-western part of the Black Sea) and regional (the western coast of the Crimea) levels. It has been ascertained before [1] that till the 70ies sea shells (more than 95 percent) – mussels, oysters, the young of venus, phaseolin and other small shellfish - had been main suppliers of biogenic alluvia. The incoming shells did not make up more than 0.078 m3/m a year [3].
The ecological catastrophe of the north-western part of the Black Sea in the 70ies which involved dying out and silting of shallow waters has brought about the death of Zernov phyllophora field, mussel and oyster habitats. The ecosystem has lost its stability and degraded. The alluvia were no longer supplied with new biogenic material. Moreover, even these days the ecosystem is not capable of effective rehabilitation.
As for the contribution that port constructions have made to the washing-out of the beaches, it has obviously been underestimated. In the shallow part of the bay the wave energy concentrates and increases (with all the consequences that follow) due to the port and coast-protecting structures and to the washed-out and steep shore on the opposite side of the bay.
The results of system analysis and bionic approach will no doubt let us choose the most appropriate ways of restoring and saving the beaches.
Let us begin with the forecast results at the global level. We should pay special attention to the problems connected with the processes that directly affect the condition of the littoral zone (transagression acceleration, activation of the latest tectonic processes, increased energy and construction costs, demographic crisis, etc.). It is obviously time to reconsider the existing view of coast protection strategy taking into account the main trends in society development.
Thanks to the efforts of the people who care, the humanity is about to realize that the global ecological crisis and humanitarian catastrophes are inevitable unless the World reaches some stability in its development under the conditions of limited resource consumption. The governments of some highly developed countries are becoming more and more aware of the danger. They are closing power stations, cutting down on nuclear weapons. The producers are getting rid of energy- and material- consuming technologies (the process of making the economy compatible with ecology).
However, “consumers” continue their ominous march. Energy consumption is rising, flora and fauna on land and in the ocean are being destroyed. Not a single inch of land do hydroengineers cede to the sea. They erect coast-protecting structures even in the cases when it obviously contradicts common sense.
It is obviously high time to work out a modern strategy of human behaviour in the high-energy zone including the littoral.
It appears reasonable to coordinate this strategy with the idea of “complex management of the littoral” [4] and “Aquapolis” system that is being worked out by MGI NANU [5].
The strategy of “flexible retreat” that is being discussed is a managing process, which is meant to increase stability and functional effectiveness of the littoral in the future. It is impossible to stabilize the whole coast. Keeping this in mind we should decide from the forecast results which coast sections are the most valuable from the economic and social points of view and work out rational projects of their preventive protection and stabilization sacrificing the sections that are less valuable.
To put this strategy into practice we need a plenipotentiary structure at the government level, which would provide financial, legal and information support.
"Entry"
Lithodynamic system of the littoral and its subsystems: management,
supply and major means
"Exit"
Management means
Stable beach (natural or artificial)
Major means:
Accumulative profile of underwater beach coast slope balance
Supply means:
Transformator and accumulator – underwater coast slope
Natural and man-caused information, energy and substance sources
Irretrievable losses of beach material
Symbols of flows:
information
energy
substance (aluvia)
Picture 1. Structural-functional model of sea coastal zone lithodynamic system
References
1. М.И. Киселева. Бентос рыхлых грунтов Черного моря, К., "Наукова думка", 1981, стр. 166.
2. Г. Одум, Энергетический базис человека и природы, М., "Прогресс", 1978 г., стр.378.
3. Экзогенные процессы развития аккумулятивных берегов в северо-западной части Черного моря, М., "Недра", 1989 г., стр.200.
4. Н.В. Шадрин, Стратегический план действия по сохранению и восстановлению Черного моря, сборник «Акватория и берега Севастополя: экоситемные процессы и услуги обществу Севастополя», "Аквавита", 1999 г. стр.7, 290.
5. В.В. Беляев, Л.А. Кавешников, В.К. Мачкевский, Ю.Т. Щетинин, Некоторые современные проблемы сохранения биосферы. Эколого-экономическая система природопользования "Акваполис" – путь к сохранению природы и человека, книга Системы контроля окружающей среды, сборник научных трудов НАНУ МГФИ, Севастополь, 1999 г, стр. 304, 292 – 302.
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