PROTECTION AND RESTORATION OF THE ENVIRONMENT VII – MYKONOS2004

CONTRIBUTION TO THE DETERMINATION OF THE "OLD FORESHORE ZONE", APPLICATION ON THE IRAKLEION AREA, KRITI Konstantinos G. Pehlivanoglou*, Zoe J. Karamitrou* The Greek Ombudsman, Quality of Life Department Xatjigianni Mexi 5, 11528 Athens. E-mail: [email protected] ABSTRACT The determination procedure of the geographic positioning of the "old seashore zone", in the year 1884, according to the legislation (Compulsory Law 2344/1940 and Law 2971/2001) requires the valuation of geologic, oceanographic and topographic archive data and field measurements in the area. In order to support the previous procedure, data from drills, significant wave height and wind measurements, wave field simulation as well as topographic and bathymetric archive data of the Irakleion area, Kriti island, were used. The upper limit of the "old seashore zone" was estimated to traces the 3.5 m. contour line, of the TOPOGRAPHIC CHART OF THE NEW PORT OF IRAKLEION, (1914), along the coastal area zone.

ΣΥΜΒΟΛΗ ΣΤΟΝ ΚΑΘΟΡΙΣΜΟ ΤΗΣ ΖΩΝΗΣ ΠΑΛΑΙΟΥ ΑΙΓΙΑΛΟΥ ΕΦΑΡΜΟΓΗ ΣΤΗ ΠΕΡΙΟΧΗ ΗΡΑΚΛΕΙΟΥ, ΚΡΗΤΗΣ Κωνσταντίνος Γ. Πεχλιβάνογλου*, Ζωή Ι. Καραµήτρου* Συνήγορος του Πολίτη, Κύκλος Ποιότητας Ζωής Χατζηγιάννη Μέξη 5, 11528, Αθήνα Ηλεκτρονικό Ταχυδροµείο: [email protected] ΠΕΡΙΛΗΨΗ Προκειµένου να υποστηριχθεί η διαδικασία καθορισµού του "παλαιού αιγιαλού", όπως αυτή καθορίζεται από τη νοµοθεσία (Α. Ν. 2344/1940 και Ν. 2971/2001), γίνεται προσπάθεια αξιοποίησης γεωλογικών, στρωµατογραφικών, ωκεανογραφικών και τοπογραφικών δεδοµένων και µετρήσεων πεδίου, κατά την χρονική περίοδο του τέλους του 19ου αρχών 20ου αιώνα, η οποία κατά τη νοµοθεσία ορίζεται ως γραµµή παλαιού αιγιαλού. Με τη βοήθεια των αποτελεσµάτων γεωτρήσεων, µετρήσεων ύψους κύµατος και ανέµου, προσοµοίωσης του κυµατικού πεδίου αλλά και µε τη αξιοποίηση τοπογραφικών και βυθοµετρικών δεδοµένων αρχείου, εκτιµάται ότι η θέση της γραµµής του παλαιού αιγιαλού στη περιοχή του λιµένα Ηρακλείου Κρήτης κατά το τέλος του 19ου - αρχές 20ου αιώνα, ακολουθεί την ισοϋψή των 3,5 µέτρων όπως αυτή ορίζεται στο ∆ΙΑΓΡΑΜΜΑ ΠΕΡΙΟΧΗΣ ΝΕΟΥ ΛΙΜΕΝΟΣ ΗΡΑΚΛΕΙΟΥ, (1914).

PROTECTION AND RESTORATION OF THE ENVIRONMENT VII COASTAL AND OPEN SEA WATER I

1. INTRODUCTION The present study aims to the estimation of the geographic positioning of Irakleion, Kriti Island, seashore zone, during the turn of the 19th century up to 20th century's start. According to the Greek legislation, the determination of the boundaries of this zone specifies the so-called "old seashore zone" of the area. The results of the geomorphologic and the stratigraphic investigation of the upper coastal layers of the area as well as the wind and the wave field in the shallower sea area were examined via a mathematical simulation model. The aim is to demonstrate the mode that, the physical indications, such as the geologic, oceanographic and topographic data, which defined by the Law 2971/2001, article 6, can be utilized by the official authorities, in order to result in safe conclusions regarding the delimitation of the public land resources. The Compulsory Law 2344/1940, article 2 paragraph 3, defined that: "In the case that due to illuviations or other reasons it is obvious that, at the time of the determination, the seashore zone position is different than in the past, according to the evidences of witnesses which examined under oath by the committee, or with the aid off other various indications, it is possible the old position of the seashore up to the year 1884 to be determined, the committee proceeds to the determination of the "old seashore zone", engraving a blue line on the diagram."

Figure 1. Geographic setting of the study area. (Background: Chart 443 and 443/1 Hydrographic Service). Indicative drills' position (•)Ministry of Environment, Physical Planning and Public Works and (+)Institute of Geology and Mineral Exploration. The recent Law 2971/2001, article 1 paragraph 3, defines that: "old seashore zone is the land zone which derived from the shifting of the seashore towards the sea, due to illuviations or constructions and it is defined by the modern seashore limit and the limit of the older seashore". The same law, PROTECTION AND RESTORATION OF THE ENVIRONMENT VII COASTAL AND OPEN SEA WATER I

article 5 paragraph 3 defines: "The committee defines the position of the old seashore zone, which existed up to the year 1884, if there are private properties or even older (than 1884) if there are not such properties, as long as the position of the old shoreline results from land indications or other conclusive evidence…" According to the aforementioned legislation, the innermost limit of the "old seashore zone" is defined by the innermost limit of the seashore zone of the year 1884. Therefore this limit can be defined proportionally to the modern seashore as "the zone that washed by the maximum but usual sea wave run up" but with a date reference to the year 1884. The term " maximum but usual sea wave run up" denotes these wave rides over the coasts, which happen or happened at least annually under extreme weather conditions. According to Doris, (1995), for the determination of the "old seashore zone" all the available data should be taken under consideration, such as aerial photographs, signs of debris, the state of the coast etc. The data, which were used for the aim of the present study, are: 1) The results of the interpretation of the drills performed by different public services (Ministry of Environment, Physical Planning and Public Works and Institute of Geology and Mineral Exploration), 2) The significant wave height which was calculated by mathematical simulation model, and 3) The geomorphology of the coastal zone during that period. For the calculation and/or the estimation of these conditions was considered that: 1) The weather conditions did not change significantly on the Northern part of the Kriti Island since 1884, 2) It is possible the geomorphology of the sea bed to be reproduced by the available topographic and hydrographic charts and diagrams of that period, 3) From the same charts and diagrams, it is possible to reproduce the geomorphology of the subaerial zone of the coast, previous to the beginning of the works dated in the year 1914, for the construction of the Irakleion harbor. 2. GEOLOGY - PHYSICAL SETTING OF THE AREA The wider region of Irakleion gulf, Kriti Island which is examined in the present study, constitutes small part of the Northern coast of Kriti Island, (Fig. 1). At the present time period, the morphology of the landward coastal region includes, a part in front of the old city of Irakleion with intense bathymetry, which presents alterations between small hills and small flat fields, up to the distance of 150-170 m. from the coastline. Eastwards of this part towards the N. Alikarnasos area as well as landward, hills of a few tens of metres are changed to extensive flat field areas. Westwards of the Irakleion, towards the region Stomio - Ammoudara the bathymetry of the coastal area is smoother including an extensive sandy beach, due to the illuviations of the torrent Giofiros that discharge in the area. At the turn of the 19th up to the start of the 20th century, the wide area of Irakleion Kriti had a soft bathymetry. A part of coastal land area (subaerial zone of the coast) was flat, with the exception of some small hills of few tens of metres height, towards the eastern limit and southern of the harbour. According to the “Plane Hydrographic du Port et de la Rade de Cantie”, (1904), (Fig. 2), and “Diagram of the region of new port Irakleion”, (1914), that was made for the preliminary study of the harbor construction of the Irakleion city, the subaerial zone of the coast before the works, were extended in altitude up to 3.5 m. as well as in a distance of 20 - 50 m. from the coastline, in front of the "Sabbionara" and the northern wall. A small rise of 10 metres formed eastward of that beach and a small torrent, which supplied with terrestrial material the coastal area. Eastern of torrent the subaerial zone of the coast beach had smoother bathymetry, extended in distance of 60 - 80 metres from the coastline, while more southern landward small hills up to 25 - 30 metres height existed. PROTECTION AND RESTORATION OF THE ENVIRONMENT VII COASTAL AND OPEN SEA WATER I

The result of this geomorpholocic setting of the coast area was smooth gradient of the subaerial zone of the coast, varied between 7% in the westerner up to 4% in eastern part. In contradiction to the land area, the underwater shallow seabed had a smoother bathymetry and a smaller inclination towards the eastern and mainly to the westerner limit of the coastal area (Figures 1 and 2).

Figure 2. Extract of the hydrographic chart of the Irakleion coastal area, (Alfred Diemer-Edouard Quellennec, 1904), Scale 1:2000. As it results from the study of geological map of the Institute of Geological and Mineral Research (IGMR), Quaternary and Neogene formations as well as alluvial deposits prevail in the wider area. These coastal area formations in front of the old city of Irakleion are covered mainly by debris. The Neogene formations on the Eastern part of the study area, consists of limestones which altered to calcareous marls or marly limestones. The formations in the central part of the area where the port of Irakleion was constructed, consists of homogeneous marls, marly limestones and clays with plant or animal organic remains. The Quaternary formations consist of marine limestones, sandstones, conglomerates and marls in the western part, marine sandy terraces in the area of Irakleion harbor as well as fluvial deposits or enclosed basin deposits towards the eastern part close to the streambed of the Knossanos torrent (Polyhronakis et al., 1999). The extensive nearly straight front of the coast, was almost unprotected from the northern, northeastern and partly north-western winds. The unique protection of narrow sector of the coast derived by the island Dia, north of the Irakleion City. The sea fetch extends up 75 n. m. to the north, 120 n. m. to the northeast and 150 n. m. to the northwest directions. Due to the extended fetch and the strong or stormy winds, which often blow in the area, the coast was undergoing the high waves action, before the extensive constructions, which began in the turn of the 20th century and aimed to the extension and protection of old Irakleion harbor.

PROTECTION AND RESTORATION OF THE ENVIRONMENT VII COASTAL AND OPEN SEA WATER I

3. METHODS In order to recognize the geomorphology of the coastal area, calculate the significant wave height and simulate its effect on the coastal area previous to the harbour works', oceanographic, geomorphologic and stratigraphic data were considered. 3.1. Oceanographic data a) The data of the significant wave height and respective wind direction were used, from the continuous measurements of the National Centre's for Marine Research observation buoy, in the Cretan Sea, located at 35° 37' 12'' N, 25° 38' 24''E, NE of the Irakleion. These data referred to a specific period of the 2001 winter. During that period extreme meteorological phenomena had been observed (strong NW winds), which were possible to create high waves in the shallower studied area. b) The theoretical calculation and transformation of the significant wave height in the shallower coastal area of Irakleion city, was performed by the National Centre of Marine Researche. This calculation was based on the previous mentioned significant wave height measurements of the deep sea and their transformation by a mathematic simulation model for the shallower area. In the mathematic simulation models of the wave transformation from the deep sea to the nearshore/coastal area, the sea fetch, the wind speed and direction as well as the bathymetry are taking into account. For the study of the wave field in the nearshore/shallow area, the SWAN wave prediction model was applied. It is a 3rd generation wave prediction numerical model which is based mainly on the wave action balance equation. The model accepts the following input data: a) wave parameters (the significant wave height, the average wave period and direction) and b) wind parameters (wind speed and direction). Also all the wave phenomena (diffraction, reflection, and refraction), are fully modeled providing reliably describe of the wave propagation for coastal regions. Primarily, the nearshore/coastal study area of Irakleion, Kriti (25° 22' E to 25° 36' E and 35° 16' N to 35° 32' N) was defined, as this appears in the figure 4. Then, the grid for the application of the wave simulation model was selected, and finally the suitable equations were applied and solved. The grid of the wave simulation model was selected in such a way that the limit conditions that will be applied are reliable. This mode of calculation provides a direct evidence of the significant wave height that affects the coastal area and proves, which is "the land zone that is affected by the maximum but usual sea wave run up". 3.2. Geomorphologic and stratigraphic data. The stratigraphy of coastal area as well as the qualitative structure of individual layers was studied with the help of the drillings performed by the Institute Geological and Mining Researche in March and April 1999, and those of the Ministry of Environment, Physical Planning and Public Works in December 1967. The places of the drillings are indicated on the topographic diagram of the area (fig. 3). (Koutsouveli, 1999, Polyhronakis et al., 1999). 4. DISCUSSION 4.1. Geology - stratigraphy The study of the drills, that were performed in the central and westerner part of the coastal area of the Irakleion harbor (Fig. 3), indicate that: a) The surface layer which expands from 1 to 4 metres depth, consists of debris (rubbles, remains of constructions etc.) which indicate the human intervention. The thickness of the debris is smaller in the landward and southern part of the area, closer to the Sabbionara (drilling Γ3). On the PROTECTION AND RESTORATION OF THE ENVIRONMENT VII COASTAL AND OPEN SEA WATER I

contrary their thickness increases considerably towards the northern part, closer to the coastline as well as in north-western and western part of the area. b) Under the aforementioned surface layer, a thin subsurface layer is recognized in some drills (G1, G3), 30 to 80 cm thick, where a mixed sandy - humus material is observed. This layer is absent from drills G2 and G4. c) In the drill G1 closer to the coastline as well as in drill G2 in the central part of the area, under the aforementioned thin layer up to the 7 m depth, a marine origin material exists. The sandy or sandy-clay character of this material is similar to those of the coastal area material as well as to the marshy seabed materials. On the contrary in the southern drill closer to the Sabbionara (drill G3), under the aforementioned thin subsurface layer of mixed material the bedrock (marly limestone) is observed. d) In the eastern drilling G4, under the 4 m thick surface layer with debris, rubbles etc., appears a sandy layer mixed with pebbles, as well as separate layers consisting either of pebbles or sand. These structure denotes river action as well as intense transport of the material downwards. Under the aforementioned layers appears the solid bedrock in-depth of 8,5 m. The study of the drills that has been performed by the Ministry of Environment, Planning and Public Works conclude to similar results. Among them the drills g1, g2, g3, g4, g5 and g6, (Fig. 3), present a surface layer of debris and a subsurface fine sandy layer, 0.7 to 3.5 m thick. Moreover the drills g15, g16 and g17, close to the small torrent Knossanos, present a fine surface sandy layer, 1.5 to 3 m thick, succeeded by the solid bedrock of the area. Some differences, regarding the thin subsurface layer, between the results of the drills of the Ministry of Environment, Planning and Public Works and those of the drills of the Institute of Geological and Mineral Research (IGMR), exist. The subsurface layer, of mixed sandy - humus material, which denotes alternate deposition of terrestrial and marine environment, either was not presented in the drills of the Ministry of Environment, Planning and Public Works or was not evaluated due to the small thickness. 4.2. Wave - wind conditions Data of the wind and the respective significant wave height, in the Cretan Sea area north of Kriti Island, measured by the National Center of Marine Research, were also used. These data lead to the calculation of the significant wave height in the coastal area of Irakleion, therefore to the bigger wave ride on the land under extreme weather conditions. The previous calculation was performed with the assumption that the climate and the wind conditions have not changed considerably during the last century. Also the thorough study of both modern and older maps and diagrams of the area provided an explicit image of the bathymetry of the offshore as well as of the nearshore/coastal area (Fig. 2 and 4). Consequently it became possible to apply the mathematic simulation model for the critical chronological period which is stated by the legislation. A time period during November 2001, when NW winds of 15 m/sec speed (7 Beaufort) prevailed, was selected for the calculation of wave in the nearshore/coastal area. The statistic data sheet of the National Meteorological Service, Irakleion station, for the time period 1955-1987, states that, the annual frequency of the north sector winds (North-Easy, Noth, North-West) of 7 Beaufort or even bigger, is 0,6%. This frequency corresponds to 2-3 days per year, when 7 Beaufort or even more prevail in the area. The aforementioned wind field, is considered that it creates a wave field which fulfills the condition which is defined by L. 2971/2001, regarding the wave height and the respective annual frequency, during a wintry period or even the summery period when "etesian" winds predominate in the Aegean sea.

PROTECTION AND RESTORATION OF THE ENVIRONMENT VII COASTAL AND OPEN SEA WATER I

Figure 3. Indicative positions of the drills. (•)Ministry of Environment, Physical Planning and Public Works and (+)Institute of Geology and Mineral Exploration. During this time period, of November 2001, the significant wave height in the position of measurement (Cretan Sea, NE of Irakleion city), reached the 4,91 m with a respective wave direction of 49°, under 15 m/sec (7 Beaufort) wind speed. The previous mentioned significant wave height suggests that the biggest wave height was greater than 5 m (Poseidon System, 2003). Accepting that the wind speed in the area exceeds the 15 m/sec (7 Beaufort), even with smaller frequency, (0,132% per year, according to the statistic data of National Meteorological Service, Irakleion station), then it is suggested that the significant wave height will exceed the 5,5 - 6,0 m in the location of the measurement. The nearshore/coastal wave prediction model was executed with a 200 m resolution, and the boundary conditions (input data) of the table 1, that were applied on the limits of the simulation grid. TABLE 1. Boundary conditions that were applied on the limits of the simulation grid Hs Tm Θw uw θw 4,7 7,0 50 15,5 47 Hs : is the significant wave height in metres, Tm : is the average wave period in seconds, Θw : is the average wave direction in degrees, uw : is the wind speed in m/s and θw : is the wind direction in degrees. The terms Θw and θw denote the direction from which the wave and the wind come. Also 0 degrees correspond in the north direction.

PROTECTION AND RESTORATION OF THE ENVIRONMENT VII COASTAL AND OPEN SEA WATER I

Figure 4. Indicative delineation of the simulation grid as well as of the shallow and the offshore area bathymetry. The application of the wave prediction model in the nearshore/shallow coastal area, close to the land resulted that: a) a 4,9 m significant wave height in the deep area, at the place of measurement, under a 7 Beaufort wind force, creates a significant wave height greater than 3 m, close to the coastline, where the depth is less than 5 meters, b) in the coastal area and the beach, the significant wave height was expected not to exceed 3.2 m. Considering irregular waves normal to the coastline, according to Mase (1989), the maximum wave run up on the subaerial coast was estimated to 3.2 m, while the mean value of the 1/3 of the higher wave run up was estimated to 2.17 m. It is logical to deduce that wind force 8-9 Beaufort will create a 5,5-6,0 m significant wave height in deep area, as well as a 3.6 - 3.9 m maximum wave run up on the subaerial coast. 5. CONCLUSIONS Taking account of the wave height at the deep and shallow area as well as of the coast's relief, as it is presented in the older available hydrographic and topographic maps and diagrams, such as Plane Hydrοgraphic du Port et de la Rade de Cantie, (1904), and Diagram of the region of new port Irakleion, (1914), considering also that the wind conditions have not changed considerably during the last century, we come to the following conclusions:

PROTECTION AND RESTORATION OF THE ENVIRONMENT VII COASTAL AND OPEN SEA WATER I

1. The coastal area presented a mild slope varied between 4% and 7%, while in the underwater beach the gradient was even gentler. 2. The area was influenced by high waves, which in the shallower/coastal area of the 5 m depth, exceeded 3 m, under the force of 7 Beaufort wind. It is believed that under the force of 8 - 9 Beaufort winds the wave height much greater than 3m. 3. The range of the sub aerial sandy zone as it results from the available topographic diagrams was large. A part of the beach has been created by the wave action while another part by the aeolian transport of the sand. However the part of the coastal zone that was affected by the wave action, (as this it is described in the aforementioned paragraph 2) had a range between 20 and 80 metres. 4. Despite the fact that the significant wave height, which affected the nearshore coastal area, was greater than 3 m under 7 Beaufort wind force, the maximum wave run up on the sub aerial coast was expected not to exceed 3.2 m level. Under the force of 8-9 Beaufort wind force, the maximum wave run up was expected not to exceed the 3,6 m level along the sub aerial zone, due to its great range and the attenuation on the sandy surface. 5. The thickness of the materials, which were used for embankment of the area, as the drills certify it, supports the suggestion that the maximum level, which was possible to be reached by the wave action, could not exceed the approximate level of 3.5 m, as it appeared on the topographic diagram of year 1914. 6. Consequently the upper limit of the foreshore zone in 1884 (the so-called "old foreshore zone" according to the Compulsory Law 2344/1940 and the Law 2971/2001), should be the 3.2 m level, as it is recognised on the oldest reliable topographic diagram, entitled " Diagram of the region of new port Irakleion ", (1914) scale 1:1000, coming from "Technical Study of the Irakleion city harbour construction, of the 1914". 6. ACKNOWLEDGEMENTS The authors wishes to acknowledge the National Centre for Marine Research who kindly provided the wind, wave field data and the wave prediction model estimations for the nearshore area, as well as to the colleagues Dr Michael Tsimplis and Dr Nikiforos Kypraios, for their comments. REFERENCES 1. Alfred Diemer - Edouard Quellennec, (1904). PLANE HYDROGRAPHIC du PORT et de la RADE DE CANTIE. Scale 1:2000, Irakleion Port Authority. 2. Diagram of the Region of New Port Irakleion, (1914). Scale 1:1000, "Technical Study of the Irakleion city harbour construction". Irakleion Port Authority. 3. Doris, E. (1995). The Public property. Shoreline, beach, marine environment pollution. Vol. B' Issue A'. Edit. Sakkoula, Athens. 4. Extract of the map "The city of Candia (Irakleion)", (1843). Scale 1:7120, British Admiralty. Irakleion Port Authority. 5. Irakleion Harbour (Kriti Island), (2002). Chart No. 443/1. Scale 1:5000, Hellenic Navy Hydrographic Service. 6. Koutsouveli, An. (1999). Geologic study and determination of the old coastline in the land area of the Irakleion harbor, Kriti. Unpublished technical report of I. G. M. R., Athens, 23 p. 7. Kriti Island, East - Central Part, (1998). Chart No. 443. Scale 1:100000, Hellenic Navy Hydrographic Service. 8. Mase, H., (2002) in Coastal Engineering Manual (CEM), U.S Army corps of Engineers. 9. Polyhronakis, A., Athanasoulis, E., Zourbakis, B. (1999) Geological report on the research drills of the Irakleion harbor land area. Unpublished report of I. G. M. R., Athens, 11 p. 10. Poseidon System, Institute of Oceanography, Hellenic Center for Marine Research, (2003). Web page. PROTECTION AND RESTORATION OF THE ENVIRONMENT VII COASTAL AND OPEN SEA WATER I

The estimation of the geographic positioning of the ...

COASTAL AND OPEN SEA WATER I .... taking into account. For the study of the wave field .... the offshore as well as of the nearshore/coastal area (Fig. 2 and 4).

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