Bathymetry maps derived with satellite-based multispectral sensors have been used extensively for environmental and engineering coastal studies and monitoring. However, so far this technique has not been widely exploited in other coastal applications, such as underwater archaeology. Submerged settlements and shipwrecks are often located in water depths where the application of multispectral satellite data is feasible. This could lead to more efficient field work practices thus enabling more optimal allocations of costs and labour during archaeological excavations. This study explores the contribution of processed satellite bathymetry maps to the recording of two archaeological coastal sites: a submerged prehistoric settlement in Greece and a shipwreck of a modern cargo vessel in Italy. The results indicate that even though the accuracy of satellite derived bathymetry is high, the level of detail (spatial resolution) is not sufficient to fully replace field-based measurements. However, the use of satellite data complements the existing techniques and can help to place the archaeological sites within a broader spatial context as well as to efficiently monitor the deterioration of a site due to natural causes or human activity, which inevitably leads to risk management. When the study of larger objects is involved (for example First World War shipwrecks) the potential of using satellite data in underwater archaeological studies becomes more promising.
The paper discusses the discovery of a logboat in Lake Kromszewickie. The description of circumstances of the discovery is preceded by a brief biological and geographical characterisation of the basin and a reference to the findings of archaeological fieldwalking. Further in the article, a detailed description of the site and the discovered object is presented. The dugout, resting at a depth of approx. 7 m, is 4.25 m long and 0.42 m wide. At a short distance from it, a bovine horn and deer antlers were found. Based on the typology by W. Ossowski, it can be carefully assumed that the described logboat matches the characteristics of similar objects from the 14th century.
During the research led by the European Institute for Underwater Archaeology at Heracleion a huge statue of black diorite was found on the site of the Temple. Preserved in four parts, the sculpture is nearly complete (2.20m). It represents a woman standing, with arms on her sides down and slightly forward. In her left hand she hold the sign ankh and on the chest of her garment she bears the ‘knot of Isis’. Also the hair, arranged in long, rolled-up curls, are characteristic for the goddess. But the broad flat diadem is clearly a royal one, therefore it is possible to see in this sculpture an image of a ptolemaic queen assimilated with Isis. Certain is that Berenice II, the wife of Ptolemy III, wore on some portraits this kind of ‘isiac’ hairdress. Close to the Heracleion statue are portraits of Cleopatra II, sister-wife of Ptolemy VI, and of her daughter – Cleopatra III. Distinction of the portraits of the mother and daughter is difficult, but considering the long reign of the last one, the Heracleion statue seems more probably an image of Cleopatra III as Isis.
In the early Middle Ages, fishery was one of the primary means of obtaining food. This activity was also one of the daily activities of the community living on Ostrów Lednicki, as recorded in the historical material. During more than forty years of underwater research, a significant collection of items related to fishery was amassed. As a result, it is possible to try to reconstruct this aspect of the economy. In addition, thanks to the results of archaeozoological studies, it is possible not only to infer the fishing techniques, but also the culinary preferences of the inhabitants of Ostrów Lednicki. Among the relics, one can distinguish objects used for both mass and individual fishing. Mass fishing techniques can include net fishing, the remains of which in the form of floats and weights were found during the survey. Mass fishing methods can also include the use of fish traps. One of such wicker fish traps („wiersza”), along with bait and loot, was found during surveys of the Poznan Bridge. Such fishing activities were used to provide large quantities of fish for the inhabitants of Lednicki Ostrów. The archaeological material also allows us to distinguish quite individual fishing methods. These included the use of spiked tools such as fish gigs. Among the very interesting relics are also fishing lures, which are interpreted as elements of fishing rods. This is a rather inefficient fishing method. However, evidence for the use of fishing rods is provided by a text from a page from an Anglo-Saxon prayer book dating to around 1000, on which St. Peter successfully fishes with a fishing rod. An important aspect of the reconstruction of the Lednica fishery is the comparison of ichthyological and archaeological material, which are compatible. Fish species identified through bone analysis could have been fi shed with tools identified in archaeological relics. Therefore, it can be concluded that a large part of the fish consumed by the inhabitants of Ostrów Lednicki was obtained locally. It should also be noted that traces of imported fish have been found in areas where the elites resided. Despite such intensive local fishery, the demand for fish was so great that certain species desired by the princely court were brought to Ostrów Lednicki. These species were salmonid fish and sturgeon, whose taste qualities made them particularly desirable to the upper classes. The Lednica fishery provided a means of quite important occupation for the community living on the island. The amount of fish, the variety of fishing methods suggests that it was an important way of acquiring food, and the demand for such dishes grew with the development of Christianity in the early Piast state.
Advanced noninvasive research carried out in “The cradle of the Piasts: archaeological underwater prospections in the area of Lednickie Lake” (“Kolebka Piastów archeologiczne prospekcje podwodne w rejonie Jeziora Lednickiego”) project, provided a new collection of artefacts and archaeological sites. In the first stage of the project an archive research was carried out and it showed that there are 61 archaeological sites of different character and chronology in the close proximity to the lake. In the further part of the project, non-invasive research with the use of a magnetometer, a multibeam sonar and a subbottom profiler were conducted. This stage of the project was possible due to cooperation between the team from the Maritime Institute in Gdańsk, which was conducting hydroacoustic research, and underwater archaeologists. In the course of the survey of bathymetric anomalies between Ledniczka island and the west coast of the lake, construction elements were identified. Therefore, the terrain between an island and the mainland was thoroughly searched in order to verify the object which was found. During the search of the bottom by the divers in the designated place, more horizontal structural elements were identified. Localizing vertically impaled wooden constructions identified as piles, was the key point. These elements confirm that in the described place, there was a third bridge on Lake Lednica. Samples for dendrochronological and radiocarbon dating were collected from the P1, P4, P5 piles and V object. Only the sample from object V was suitable for dendrochronological dating, as it did not contain a sapwood layer. As a result it was possible to determine the date when the tree was cut, i.e. after 1293, hence most probably at the turn of 13/14th centuries [Ważny 2017]. Sample wood from pile 1 was subject to radiocarbon dating and the 1085±30 BP date was obtained. After calibration it can be said that it is 68.2% probable that the analyzed material comes from 900–993 (900–922: 22.3%; 948–993: 45.9%). Whereas it is 95.4% probable that it comes from 894–1016 (894–932: 30.5%; 937–1016: 64.9%) [Goslar 2017]. In conclusion, it can be said that during the research, the relics of the bridge leading from the mainland to Ledniczka island located on the W–E axis were localized. The crossing is located at the narrowest place between an island and the mainland. This is around 100 meters and this is the probable length of the bridge. On the basis of the variety in the degree of wood conservation, as well as diverse shapes of the construction elements, and especially the obtained dates from the radiocarbon and dendrochronological datings, it can be assumed that there are two bridge crossings which date to the 10th century and the turn of the 13th and 14th centuries. During the 2017 research season an interesting discovery was made. After several seasons of underwater works, a new object was localized and identified as bridge relics. It shows the great archaeological potential of Lednica Lake and how the use of new noninvasive methods can lead to spectacular discoveries. The bridge relics were only identified on the surface level, therefore it is difficult to draw far-reaching conclusions. However, dendrochronological dating makes it possible to determine the origins of the bridge to the 13th/14th century. Militaria found near the bridge are also from this period. The C14 date, which estimates the age of one of the piles for the 2nd half of the 10th century, is very interesting. It can indicate that there were two bridges with different chronology. However, in order to confirm this, further excavation works must be conducted.
Abstract: The article discusses theoretical assumptions and the terminology of underwater archaeological research and specialized areas of interest included in it, such as maritime and nautical archaeology. The introduction briefly describes the evolution of scientific underwater research in a pan-European context and Polish approaches. The main part of the text attempts to present and set in order most of the theoretical assumptions that are already in existence, which seems to be poorly known by the Polish archaeological community. The article is based on the studies by K. Muckelroy, S. McGrail, M. E. Jasinski and J. Adams. Special emphasis was placed on determining the scope of the research area in terms of maritime, underwater and nautical archaeology, which often are used in Poland interchangeably and the areas that currently need improvement or changing. In a separate sub-section, the issue of maritime cultural landscapes are presented. It is a concept which was framed by Ch. Westerdahl and presents the meaning of artefacts related to a „water” environment, but which have been deposited on land. Their inclusion yields a wider and more holistic understanding of past relations and cultural landscapes. The potential for widely understood underwater research conducted in Poland does not yet seem to have been fully exploited. It is appropriate, therefore, to use the material that already exists and exploit it in a wider theoretical framework rather than simply working on gaining new material
In the 2015 season, the underwater research in Lake Lednica focused on further exploration of two exploration plots of the Poznań bridge — 7 in the XCV area and 5 in the XCIII area and on the opening of a trial trench in the area of Ostrów Lednicki island. During the exploration of plot 5 in the XCIII zone, the wicker object in a radiating out shape was localised. Because of its archaeological value and the need of further exploration, the object was excavated and handed over to the Museum of the First Piasts at Lednica for preservation. The excavated object is probably a trap, a type of fish trap called ‘wiersza’ (a wicker fish trap). During examination of the object and cleaning after excavation, a great number of animal bone remains were collected and analysed. They almost exclusively came from fishes. In the bone material, the remains of several fishes were found: a catfish, eight perches, a pike, the fishes of the Cyprinidae family, including at least two roaches, as well as three remains of a pig. In the case of a catfish and the perches there were elements from all parts of the skeletons, while several bones belonged to two roaches and there was one pike tooth. The latter element was probably included in the assemblage accidentally. The conducted analysis shows that the catfish with SL (standard length) 70–75 cm and the perches, in most cases the large ones with SL=35–45 cm, were trapped in the fish trap. It is, however, not certain whether the roaches caught in the trap or had earlier been caught by predatory fish or fishes found in the trap. It is suspected that a phalanx and two ribs of a young pig, which probably come from the same animal, are the remains of a fishing bait placed in the wicker fish trap. Radiocarbon dating of the organic material which the object was made of indicates that it was placed after the bridge was no longer in use, probably in the late 12th or the early 13th century. For unspecified reasons the described wicker fish trap was not emptied and was left among the relics of the early medieval bridge. The discovery of the remains of the wicker fish trap and the analysis of its contents brought new information about one of the ways of fish harvesting used by the inhabitants of the area of Lake Lednica and its efficiency.
The shipwreck F53.26 was discovered in 2010 by employees of the Maritime Office in Gdynia. The object is located 4.5 metres deep in the Westerplatte area, 101 metres from the current coastline. It is located a short distance of 11 metres to the northwest of the F53.18 shipwreck. Preliminary research of the object was carried out by archaeologists from NMM in 2010 and 2011. During three research seasons in 2017–2019, a detailed inventory of the shipwreck was made using photogrammetric 3D documentation as part of the project ‘Wirtualny Skansen Wraków Zatoki Gdańskiej’ (‘Virtual Open-Air Museum of the Gdańsk Bay Shipwrecks’). This documentation, created during all three seasons, was finally combined into one 3D model using the GeomagicWrap program. This model shows the entire exposed structure of the wreck with processed sandstone pieces within it. As a result of the research, the bottom part of a flat-bottomed boat with a spindlelike shape, 14 metres long and 2.35 metres wide, was identified. The bottom of the wreck consists of five pine staves, 10 cm thick and 46 to 51 cm wide. The elements of the transverse stiffening are oak floors spaced every 18–20 cm, 13–19 cm wide and 9–11 cm thick. On the floors there are partially preserved internal formwork staves, 30–45 cm wide. A 32–44 cm wide and 6–7 cm thick keelson runs through the longitudinal symmetry axis of the wreck, preserved at the length of 12.5 metres, with a grooved mast socket 3 cm deep. On both sides of the bottom part of the wreck, fragments of the sides in the form of single oak staves have been preserved. On the wreckage structure and in its immediate vicinity there are at least 45 sandstone stones in the shape of low cylinders with a diameter of 40 cm to 140 cm. They constitute a cargo which can be interpreted as quernstone blanks. The regions of Germany or France were indicated as potential sources of these stones. On the wreckage seven lead ingots in the shape of oblong loaves with heart-shaped marks were discovered and lifted. The ingots have a length of 795 to 820 mm and a weight of 57.450 kg to 62.750 kg. Fourteen samples were taken from the wreck's hull for dendrochronological examination. Three samples were obtained from pine elements and eleven samples from oak elements. Absolute dates were obtained for three oak samples, and one of them contained sapwood. Based on this it was established that the tree was felled in 1632 and the ship was built shortly after that year. It was also determined that the oak wood used for the construction of the vessel comes from the region of Gdańsk Pomerania. This indicates that in the case of the shipwreck in question we deal with the remains of locally produced means of water transport. The analysis of the boat structure and nature of its cargo indicates that in the case of the F53.26 shipwreck, we are dealing with the bordyna type vessel remains. It was a flat-bottomed watercraft used for loading and unloading seagoing ships which could not be dealt with in the port of Gdańsk due to excessive draught. The tonnage (load capacity) of the vessel can be roughly estimated at about 60 – 80 lasts. Which indicates that the vessel belonged to the first class, i.e. the largest bordynas used for transhipment in the port of Gdańsk and its roadstead.
W 1995 r. nurkowie z Narodowego Muzeum Morskiego w Gdańsku odkryli wrak brytyjskiego statku handlowego z II poł. XVIII w., który zatonął w pobliżu wsi Dąbki u ujścia rzeki Piaśnicy. Wrak, oznaczony jako W-32, zidentyfikowano dzięki znalezionemu dzwonowi, na którym widnieje nazwa statku oraz data odlania: GENERAL CARLETON OF WHITBY 1777. Podczas swojego ostatniego rejsu General Carleton przewoził ładunek żelaza i dziegciu. Ten drugi surowiec przyczynił się do doskonałego zakonserwowania zabytków drewnianych, tworząc skorupę chroniącą je przed wodą morską. Wśród licznych przedmiotów należących do załogi znaleziono drewniany flet poprzeczny, według nomenklatury angielskiej zwany fife. Zalegał on w południowo-wschodniej części wraku, za gniazdem grotmasztu, gdzie znajdowało się najwięcej przedmiotów prywatnych marynarzy. Przypuszczalnie była to własność jednego z oficerów. Fife zachował się w bardzo dobrym stanie. Pomimo nietypowej dwuczęściowej budowy, identyfikację instrumentu potwierdziło zdjęcie rentgenowskie, ukazujące jego charakterystyczny cylindryczny przekrój. Flety tego rodzaju odznaczają się wąską średnicą, a w grze ostrzejszym i wyższym dźwiękiem w porównaniu do pozostałych fletów poprzecznych. Na powierzchni instrumentu, poniżej otworu zadęciowego oraz pomiędzy trzecim i czwartym otworem palcowym, widoczna jest sygnatura wytwórcy. Wskazuje ona na warsztat Charlesa Schucharta (1720–65), który posiadał sklep pod nazwą „Two Flutes and Hautboy” przy Chandois Street, Covent Garden w Londynie. Ponad nazwiskiem umieszczono literę C informującą o stroju instrumentu. Typ sygnatury wskazuje, że fife powstał pomiędzy 1759 a 1765 rokiem. Wśród zachowanych w światowych kolekcjach instrumentów sygnowanych przez Johna Just Schucharta i Charlesa Schucharta, znajduje się osiem fletów prostych, dwadzieścia sześć poprzecznych, trzy oboje, klarnet i fagot. Flet z wraku statku General Carleton wzbogaca ten zbiór o prawdopodobnie jedyny jak dotąd fife.
EN
In the course of the fatal voyage, General Carleton was transporting a cargo of tar and iron. This cargo facilitated the preservation of artefacts: the spilled tar formed a shell, which protected the artefacts from seawater. Therefore, the wood was not damaged nor deformed. These conditions allowed the divers to find another musical instrument, which happened to be a wooden fife. It was lying in the south-eastern part of the wreck, behind the mainmast step, where most personal belongings of the crew members were discovered. The state of preservation of the flute is good. The X-ray photo confirmed the cylindrical cross section of the instrument. It’s dimensions indicate the C# or C tuning (transposed to B or Bb). Notwithstanding its atypical two-part construction, it should be classified, according to the Anglo-Saxon nomenclature as a fife, that is „a small cylindrical transverse Flute, but with a narrower bore and hence a louder, shriller sound than the flute proper”. The maker’s marks are visible on the surface, under the embouchure hole and between the 3rd and the 4th finger hole. The name indicates that the fife was made by John Just Schuchart or Charles Schuchart. The dating suggests Charles (1720–65) as the maker. He had a shop on Chandois-street, Covent-garden, London, called “Two Flutes and Hautboy”. Based on the signature type it can be said that the fife was produced in years 1759–65. The collections around the world include 8 recorders, 26 transverse flutes, 3 oboes, a clarinet and a bassoon from the workshops of father and son. It might be possible that there are no preserved analogies for the described instrument, which enriches the known collection of Schucharts’ instruments by one fife.
The archaeological potential of Kromszewickie lake became a subject of interest since the discovery of a dugout boat and two ceramic vessels, one from early-modern times and the other associated with the Lusatian culture. Archaeological prospections in this lake started aft er reporting this discovery to the Province Conservator of Monuments. During regular explorations conducted along the eastern shore of the lake, historical material with a broad chronology from the end of the 12th century till the beginning of the 17th century was found. This material can be divided into two separate archaeological sites. The first one is the aggregation of ceramic artefacts, which probably flowed down from a site located right on the shore of the lake. On the basis of the analysis of the material two phases can be distinguished in this collection. The first phase encompasses late medieval materials. In this phase two horizons can be distinguished. The earlier one dated to the 13th-14th century and the later one dated to the 15th- beginning of the 16th century. The second phase, on the other hand, covers the times from the mid 16th century till the mid 17th century. On the south-east shore of the lake on a flooded cape, the relics of the wooden constructions were discovered. Both oaken piles with 10 -20 cm diameters, as well as much thinner piles made from soft wood, were documented there. Ceramic material from this place can be dated to the 2nd half of the 12th - 13th century. It is not possible to determine the function of the site on the basis of the current state of research. There is one more underwater site with a similar chronology in Długie lake in this area. The function of this site has not been determined as well. On the basis of the analysis of the available data, it can be assumed that there can be more archaeological sites in Kromszewickie lake. Moreover the absence of clear analogies proves the necessity for excavations. Locating both the construction in Kromszewickie lake and the archaeological site in Długie lake in the cultural-economic space of early feudal Kujawy should be a significant issue.
This brief article discusses the matter of iron and steel shipwrecks in the context of the remains of vessel SS Stuttgart, and its environmental research conducted by scientists from Maritime Institute in Gdańsk. Her shipwreck is on the Polish list of 28 wrecks being treated for environmental reasons in the Polish part of South Baltic. At the present SS Stuttgart is most dangerous sunken object on the Polish coast. She was taking part in the 2nd World War. As such they are interesting objects which can be used in the studies of underwater archaeology of the contemporary past. The authors focus on their possible use in archaeology of the data obtained during oceanographic and hydrographic research.
W-34 shipwreck represents a small, coastal merchant-vessel, used in the local seafaring within Gulf of Gdańsk. It was found close to the shoreline in Redłowo (present-day district of Gdynia). The ship was probably built in one of the minor, regional shipyards, between 17th and 18th century. For its construction were used oak and pine timbers from the local sources of Gdańsk region. The vessel was built in shell-first method with the use of lapstrake planking as its main structure integrity. At some point in its career, the vessel was equipped with the additional carvel planking, attached on the outboard side of the outer hull’s hell. These characteristics were observed on the other 11 shipwreck sites, located around the southern part of the Baltic Sea. Due to the shore conditions in the area of Gdynia-Orłowo and Redłowo, it seems possible that additional layer of carvel plankings was used to secure the bottom part of W-34 against rockery seabed.
PL
Odkryty w okolicach Gdynii-Redłowa wrak W-34 stanowi przykład niewielkiego frachtowca, wykorzystywanego w przybrzeżnej żegludze po akwenie Zatoki Gdańskiej. Jednostka zbudowana została najprawdopodobniej w jednym z lokalnych warsztatów szkutniczych na przełomie XVII i XVIII w. W konstrukcji wykorzystano drewno dębowe i sosnowe z obszaru Pomorza Gdańskiego. Kadłub wraku wykonano w technice skorupowej, łącząc zakładkowo elementy poszycia i uzupełniając konstrukcje od wewnątrz elementami szkieletu. Uwagę zwraca fakt zastosowania na zewnętrznej stronie kadłuba dodatkowego poszycia, w postaci układanych na styk dębowych klepek. Podobne rozwiązania zaobserwowano dotąd na 11 innych stanowiskach wrakowych w rejonie Morza Bałtyckiego, datowanych na okres XV – XIX w. Biorąc pod uwagę warunki hydrologiczne panujące w pobliżu stanowiska, możliwe, że zewnętrzna warstwa poszycia służyła dodatkowej ochronie dolnych partii kadłuba w trakcie nawigacji po płytkich częściach akwenu, gdzie występuje kamieniste dno.
In the introduction, this paper refers to two previous actions aimed at extracting dugout boats from the bottom of Lake Lednica (in 1960 and 1982). The main part of the text presents the third action, carried out in 2016 by underwater archaeologists and students from the Department of Underwater Archaeology, Nicolaus Copernicus University. The paper explains the subsequent stages and procedures of investigations. All the difficulties and complications that arose from the circumstances of the deposition, the raw material from which the boat was made and the size of the object are emphasised. As shown by the 1997 study, the boat is made of wood from the lime tree. The boat is now 930 cm in length and 86 cm in width. The bow looks like a slightly oval pyramid; the stern was formed in the shape of a small overhang and could have been about 1 m longer. The dugout has three bulkheads: the first is the same height as the sides, the second one is shorter than the sides by about 6 cm and the third, formed stepwise (?), starts at the same height as the starboard and keeps this height to the crack, after which it is gradually lowered, going down about 5 cm below the port. The average thickness of the starboard is 5.5 cm, while the port is 4.5 cm thick. The thickness of the bottom at the stern break, ranges from 4 cm to 8.5 cm; in other breaks, it reaches as much as 19 cm. The dugout boat is poorly preserved. It has at least nine transverse cracks and one longitudinal crack ending at the first bulkhead. Part of the damage dated certainly back from the period of the destruction of the bridge; however, a thin layer of sediments covering the side or bulkhead wood did not protect the dugout from the anchors of modern fishing boats. The boat was dated using the C14 method (680 ± 120 BP); calibrated, this points to a very wide range of dates, between 980 and 1454. However, a stratigraphic analysis indicates that the boat fell to the bottom sometime between the period the bridge was completed (964) and the last major repair of the bridge captured by dendrochronological analyses (1023). The first stage of the action consisted in the underwater exploration of the bottom deposits with a water-type ejector. This was used for removing the sediments filling the inside of the boat and those within a belt of a small width on the outside of the sides of the dugout, so that they were clearly visible to a height of approx. 10 cm. The boat was filled with a layer consisting of a large number of strongly compacted chips, which produced a few artefacts: 11 potsherds, five bone fragments and a handle of a wooden cup that was preserved in two fragments. After the whole boat had been cleaned, underwater measurements were taken, which enabled the detailed drawing documentation of the dugout in situ. The second stage consisted in cleaning the area outside the boat with 25–30 cm wide and approx. 40 cm-deep trenches running along both sides of the boat and below them. The sides were cleaned gradually, in 2 m long-fragments, to prevent uncontrolled suction of the boat from the bottom and to reduce the possibility of accidental damage. After completing the exploration of each fragment, separated from the others with natural cracks, the released parts were slipped onto a properly prepared tin ‘trough’, surfaced using a buoyancy balloon and transported close to the shore.In the third stage of the campaign, special frames were prepared for each of the nine elements. After the individual parts had been put on the frames in water, they were brought to the surface with them, secured and transported to the Conservation Laboratory in Toruń. After completing all conservation and reconstruction procedures, the dugout boat will be made available to visitors at the Museum of Polish History in Warsaw.
Noninvasive surveys and prospections are a new dynamic trend in contemporary archaeology. They represent a trend of multidisciplinary analyses of cultural heritage. Due to limited access to technology, these methods are still not widely used in underwater archaeology, in particular in inland reservoirs. For this reason a team from the Department of Underwater Archaeology of the Institute of Archaeology at Nicolaus Copernicus University in Toruń in cooperation with the Maritime Institute in Gdańsk, the Museum of the First Piasts at Lednica and the Scientific Association of Polish Archaeologists (Warsaw branch), planned and completed a project Kolebka Piastów — archeologiczne prospekcje podwodne w rejonie jeziora Lednickiego in 2017. The project was financed by the Ministry of Culture and National Heritage under the following programme: Cultural heritage, priority: The protection of archaeological monuments. In the course of the project a multibeam probe, a subbottom profiler and a magnetometer were used to conduct surveys. If the conditions and assumptions of the project allowed, a direct underwater verification was conducted. Due to multibeam sonar it is possible to obtain a reliable spatial picture of a lake bottom in high resolution, e.g. 100 or more measurement points for each m2 of the bottom, which enables one to conduct a detailed overview of a surface of the research area and objects lying on it. This method turned out to be the most effective during verification and resulted in the localization of a new medieval bridge in Lednica lake. Using a subbottom sediment profiler is at the moment the only noninvasive method of searching for non-magnetic objects sunk into the bottom. After applying it on a recognized object, such as the Poznań bridge, and after receiving the positive results, it may be assumed — with high probability — that this technology will succeed in the search for other wooden archaeological structures located in subbottom sediments. Magnetometric measurements are the next technology which was used in the researched reservoir. They are indispensable when noninvasive large scale searches of metal objects with magnetic signatures are conducted e.g. the objects made of iron or steel. In the area of Lednica lake several objects with a magnetic signature were localized. In the course of research in Lednica, three types of noninvasive prospections were applied: hydroacoustics (a multibeam probe), seismology (subbottom sediment profiler) and magnetics (Caesium magnetometer). Each of these methods helps to localize other objects and gives very interesting results; however, only after all three have been used is it possible to obtain a precise picture of the bottom of the lake together with anomalies, which to a large extent can have anthropogenic origins. It seems that the future of underwater archaeology is closely related to the described noninvasive surveys. Unfortunately it will be more difficult to achieve in shallow inland reservoirs than in sea waters, where these technologies have already been introduced for some time now.
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