Investigation of potential sites for deep ocean water development in Taiwan

Deep ocean water (DOW) is commonly referred to the water below 200 meters in the ocean that is typically cold, clean, stable, and rich in nutrients and minerals. Japan and the United States have been exploiting the DOW for applications in water, pharmaceutical, cosmetic, and fishery industries for many years. The sea bed topology in eastern Taiwan has a natural advantage that the water depth can reach 500 meters just several kilometers off shore, making it rather unique and thus economically exploitable for deep ocean water resources. The Water Resource Agency (WRA) of Taiwan has started the planning for the exploitation of the deep ocean water resources since 2000. The history and previous planning such as selection criteria for the sites for DOW in Taiwan was summarized in the papers. During 2005-2006, we conducted a comprehensive field investigation, including seabed bathymetry and DOW quality, on six most possible sites for development. The site near He-Ping has a steepest continental slope that it can reach a depth of 750 meters just 1700 meters off shore, indicating that DOW can be extracted very economically. More than 60 water quality parameters were analyzed and compared to surface waters. These parameters include heavy metals, herbicides, chlorinated compounds, dioxins, as well as essential trace elements. The results indicated that the DOW in several sites along Taiwan's eastern coast has several advantages over traditional water resources, such as not contaminated with anthropogenic compounds, rich in nutrients, and having a temperature difference close to 20 degree Celsius compared to surface waters.