Environmental Management of Watersheds
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When considering sustainable economic development in East Asia in the twenty-first century, the highest priority issues may include the solution of environmental problems such as the loss of forests, water pollution, depletion of water resources, soil erosion, and degradation of the natural environment. To solve these problems, NIES is focusing on the environmental capacity of watersheds (mountains to rivers to oceans), which serve as basic units of the environment that sustain human activity. In order to ascertain the environmental capacity of watersheds in East Asia, we are carrying out scientific observation and monitoring from the perspective of the ecological functions that support their hydrological cycles. By using numerical models to represent the closely interdependent hydrological cycles and ecological functions, we are trying to predict areas that have fragile environmental capacity. We are also trying to implement environmental management to reduce environmental impacts, develop environmental conservation plans, reconsider development plans, and apply environmental restoration technologies, etc.
Area covered by MODIS receiving stations
Integrated Monitoring Using Satellite Data in
the Asia-Pacific Region
The major limiting factors for balanced economic development in the Asia-Pacific
region include the loss of forests that accompanies economic development,
desertification, soil erosion, and the depletion of water resources. In
order to develop strategies to address the depletion or degradation of
natural resources, scientific assessments of the current situation and
changes are indispensable.
The use of satellite data is one effective way to quantitatively measure environmental changes over a wide area. This project targets the Asia-Pacific region. By developing methodologies to assess the actual changes in the environment using satellite data, it aims to find the best sustainable management techniques that take into account the human use of natural resources.
The use of satellite data allows us to employ various observational
wavelengths and ground analysis capabilities. This project uses
as imaging data provided from the MODIS advanced earth observation
sensor, mounted on board the American satellite Terra. For this
purpose, a MODIS receiving station will be built in Urumchi in
China, a network will be created with the receiving station of
the Institute for Geographical and Resources Science, of the Chinese
Academy of Sciences in Beijing, and develop the infrastructure
to monitor and assess environmental changes in the Asia-Pacific
region. In addition, in order to verify the satellite observation
results, five ecological research stations will be equipped in
five locations nationwide in China, and a system will be created
to collect the data at NIES through a communications network.
We will implement a variety of research efforts through the combination of satellite and ground data, including (1) assessing the current conditions and changes in land use and land cover, (2) detecting and monitoring the impacts of global warming and desertification, (3) observing important parameters (distribution of vegetation, land surface temperatures, snowfall accumulation, precipitation distribution, ground water amounts) relating to terrestrial, hydrological and material cycles, (4) observing important parameters relating to marine material cycles (sea surface temperatures, chlorophyll distribution, suspended matter distribution), and (5) estimating water and energy budgets and primary production of vegetation.
Toward Sustainable Development in the Changjiang
(Yang) River Watershed
The Changjiang River is the third longest in the world. Its watershed
covers 20 percent of China's land area (about five times the area of Japan),
and is home to about four hundred million people. It is the source of
about 40 percent of China's total agricultural and industrial production.
Land-use map of the Changjiang river watershed
To support this dynamic human activity, land uses are being changed dramatically in the watershed. For example, agricultural land is being converted to human settlements and industry, and forests are being cut and converted to agricultural land. These changes result in more pollutant loads from factories and towns flowing into the Changjiang River, as well as greater soil, fertilizer and agricultural chemical runoff from farms. The combined effects of these factors are creating enormous problems.
One serious impact is on the rich marine ecological system of the East China Sea, caused by increased amounts of soil, fertilizer (nitrogen, phosphorus) and hazardous chemicals from the watershed flowing into the river. There are also concerns that the massive Three Gorges Dam being constructed 1800 km upstream of the river mouth will cause serious negative impacts on the environment of the watershed. In addition, large-scale water diversion projects are under way in the Yellow River watershed which suffers water shortages, bringing water from the south to the north. Scientific consideration is essential, including monitoring, regarding climate changes on a continental scale associated with such changes in hydrological cycles over vast areas of both watersheds.
NIES is involved in developing a watershed environment management model
that focuses on water and material transport. It is being designed to
assist thinking about both the environment and economic development in
the entire Changjiang River watershed from its origin to the river mouth,
including the coastal zone.
So far we have been able to simulate the flow discharge and concentration of suspended solids, which are supplied into the Changjiang River due to the hydrological runoff. In order to collect the data necessary for construction and validation of the model NIES conducted a joint field survey of water quality and ecosystems offshore of Shanghai with Chinese counterparts in October 1997 and May 1998. The same type of research was carried out in November 1998 and October 1999 along the main course of the Changjiang River from Chongqing to Shanghai, a distance of about 2300 km. Both Japan and China have been analyzing the collected samples in order to obtain important information for the construction of a reliable model.
Results of simulation of daily flow volume of Changjiang watershed using
watershed hydrology model
Location: (550 km upstream from mouth of Changjiang River-Nanjing observation
point)
Conservation of Coastal Zone Environments
Shallow coastal areas such as tidal flats and seaweed beds are extremely
important due to their excellent ability to purify water. They are important
not only for fisheries, but also for their roles in nature conservation.
Because of the lack of scientific information on the functions of shallow
coastal areas, not enough attention has been given to conserve their irreplaceable
environments when approving construction projects there. In this context,
NIES has been conducting research projects to better understand the functions
of shallow coastal areas and their water-purification capacity, and to
apply this knowledge to environmental restoration technologies.
In East Asia, the continental shelves are well-formed, creating many shallow marine areas. These are also very important from the perspective of environmental conservation. As one case study, NIES researchers have chosen Sanbanse, a sandy shallow area at the end of Tokyo Bay, to investigate water quality and aquatic life, and to learn about the water-purification capacity of benthic organisms. They identified a number of interesting characteristics by comparing water quality, bottom sediment, and biomass in Sanbanse with those for the adjacent central part of Tokyo Bay.
Ecological
research in shallow seas
In the central part of the bay during the summer, dissolved oxygen is
very low and results in very little biomass near the bottom. On the other
hand, in Sanbanse dissolved oxygen is sufficient for aquatic organisms
year-round. The better oxygen condition affords many more benthic organisms
in terms of the number of species and biomass; dominant organisms are
the mollusks such as bivalve clams, polychaetes, and crustaceans such
as shrimp and crabs, being more than 98 percent of the total biomass (wet
weight). Among these, the biomass of bivalves was greatest, and of these
three types-Ruditapes philippinarum (Asari), Mactra chinensis (Bakagai),
and Mactra quadrangularis (Shiofukigai)-accounted for about 83 percent
of the total biomass.
It is generally known that benthic organisms have the capacity
to purify water, but research in Sanbanse indicated that in shallow
coastal areas with sandy bottoms it is the bivalves that play
the major role in water purification.
In terms of research to help the restoration of environments
that have been polluted, NIES is studying "bioremediation"
technologies using microbes to clean beaches that have been polluted
by coastal tanker spills.
During the use of bioremediation, nitrogen and phosphorus are applied
on the polluted beach as nutrients to heighten the ability of microbes
to break down oil. However, because this process has its own environmental
impacts, our research pays attention to both its effectiveness and safety.
Through our studies and experiments in Hyogo Prefecture along the Sea
of Japan, we have obtained valuable knowledge about the concentrations
of these nutrients.
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