水下文化資產調查案例分析與比較研究

Abstract

由於具備優秀的離岸風場開發條件，臺灣海峽成為近年綠能政策與風電相關產業發展的焦點。然而臺灣海峽長期做為水路運輸的要衝，頻繁的海上活動在這片海域留下了大量足跡，各項考古證據與歷史資料皆顯示此處可能藏有大量尚待發掘的人類活動遺存。因此，如何在闢建風場的同時兼顧無價的文化遺產，便是需要政府與開發單位共同深思的課題。 自2015年起，我國藉由水下文化資產保存法的發布，明文規定水域開發前需執行水下文化資產調查，以便保護潛在的古物。此舉雖使水下文化資產調查成為常態，但因與世界各國相比起步時間較晚，作業上仍存在許多需各方共同協調與合作解決的問題。 水下文化資產調查表面上是以探測技術為主，實際上卻是需要考古專長與探測專長結合的跨領域作業。綜觀過去的調查案例，經常可以發現事前的史料研究與現場探測工作幾乎是各自獨立。如此壁壘分明的情況看似是有效分工，實際卻衍生了許多問題。例如，水下目標物搜索的效益與對目標物的理解程度有關，具體且充足的背景資訊如目標物外觀型態、尺寸、材質等，以及潛在的熱區位置與範圍，在規畫搜索策略及資料判釋時都能成為重要依據，但多數案例的事前研究結果經常無法提供足量的資訊。再者，現行用於調查的探測技術在開發時皆不是以考古為目的，而是水文調查、地質探勘等的調查工具，可說在預設目標物的規模上就存在極大差異，也導致這些工具用於水下文化資產調查時有其限制，並非提高儀器解析度或測量密度就足以彌補，這一點是所有參與調查的人員都必須了解的。 本文旨在透過各國各式調查案例的研究與分析，嘗試整理與歸納具體可行的建議，以協助改善臺灣與周邊地區的水下文化資產調查成果。內容分為以下部分：探測技術、法令規章、各地調查範例與我國調查案例等。探測技術部分為現行調查工具的簡介，包含技術原理、調查用途與技術限制等資訊。法令規章彙整了數個較早發展水下考古調查的國家法令，以觀察他國與我國法令在調查作業規範上的異同。各地調查範例蒐羅世界各地已發表的調查案例，並將之整理分類成較能做為探測依據的數種類型，再根據不同類型剖析其調查策略。我國調查案例則於我國相關法令發布前後各擇一例，除了介紹調查內容與方法，也試圖分析法令發布為調查作業帶來的影響。 本文嘗試以較易為一般大眾接受的文筆寫作，希望任何閱讀本文的讀者都能輕鬆的理解與掌握文中內容。

Due to the potential energy of offshore wind field, Taiwan Strait has become the target of green energy policy and wind power industry. However, Taiwan Strait is rich in archaeological and historical human trace since the long history of maritime activities. Based on this situation, the first task of the government and the developers is how to build the wind field but not disturb any site, structure, or object of historical or archaeological significance. In recent years, the Government of Taiwan has put considerable effort into the research and regulation related to Underwater Cultural Heritage (UCH). The Underwater Cultural Heritage Preservation Act, which follows the Convention on the Protection of the Underwater Cultural Heritage announced by UNESCO in 2001, was published to set an official standard for development and management in 2015. Other related laws and regulations were soon announced later on. Even though the UCH survey is an essential part of the environment impact assessment in Taiwan, the results of the survey are usually unsatisfactory. Although not designed for archaeological use, marine geophysical techniques such as side-scan sonar, multi-beam sonar, magnetometer, and sub-bottom profiler become the major tools used in the UCH survey. The powerful and interdisciplinary approach is accompanied by several problems. For example, it can be observed that desk-based research and the detection are usually separate. The result is, for most cases, the work of identification being difficult without enough background information applied from desk-based research. On the other side, the scale of artifacts is very different from geological structure. The huge difference sets a limit which cannot make up by increasing the resolution or sampling density on the ability of geophysical techniques in the UCH survey. It must be realized by all people who participate in the survey. The aims of this study is to provide the suggestion that can help to improve the results of the UCH survey in Taiwan. The content includes the tools used in the survey, the related laws and regulations, the cases from Taiwan and other country. The chapter of tools may introduce the principle, the purpose, and the limit of these techniques. The part of laws and regulations may search and compare the related official documents from the government of Taiwan and other country. The overseas cases may be categorized according to different properties, and be analyzed in order to realize the methodology. One of the two cases from Taiwan was finished before the announcement of the laws. Besides the content and method of these survey, the influence of the laws is involved in the discussion.