Forecast Mekong: Visualizing Shared Waters
The Mekong is one of the world's great rivers cascading through six Asian countries from
the Tibetan Plateau to the South China Sea, connecting China, Myanmar, Laos, Thailand,
Cambodia and Vietnam.
How one country uses or changes the waters of the Mekong upstream can have important
implications for the health of the river and people downstream.
Increasing demands for hydropower and irrigation have prompted several countries to
plan the construction of large dams on the Mekong River and its tributaries. The
cumulative effects of such dams can be quantified through the use of hydrologic data and
computer models. Visualization tools can help people develop a shared understanding of
river resources and provide a science basis for critical decisions about regional
development and sustainability.
In 1995, the nations of the Lower Mekong basin established the Mekong River
Commission to assist in the integrated management of the river flow and its ecosystem
benefits.
The Mekong River Commission, or MRC, has developed a suite of hydrology models
within a decision-support framework to forecast changes in river flow and water quality
from proposed development projects such as dams.
The U.S. Department of State in cooperation with the U.S. Geological Survey and
university partners are developing visualization tools to help policy makers and planners
communicate and evaluate complex river issues.
The flood waters of the Mekong River are critical to the food security and livelihoods of
millions of people in Southeast Asia.
From July to December, the Mekong swells with the addition of snow melt and monsoon
rains, peaking in September and October, before receding to annual lows during the
normal dry season.
When turbid flood waters of the Mekong join the Tonle Sap River in Cambodia, there is a
reversal of flow which more than quadruples the size of the unique Tonle Sap Lake.
The natural expansion and contraction of the Tonle Sap Lake each year accounts for one
of the world’s most abundant inland fisheries – a resource that is critical to food security
in the region.
Upstream dams pose potential environmental threats to the Tonle Sap and the lower
Mekong River and Delta. While dams and reservoirs provide valuable services to society,
they can also alter
normal or natural flow regimes and fish migration.
And while the impact of a single dam may be minimal, the cumulative effect of tens or
hundreds of small tributary dams within a larger river system can be substantial
depending on dam location, operation, and size.
Over the next 20-30 years, the major area of water resource development is anticipated to
be hydropower, the fundamental feature of which is the shift of water from the wet to the
dry season via reservoir storage.
Increased dry season flow decreases the risk of water shortages and increases the options
for dry season irrigation to produce a second or third rice crop.
Reservoirs and dams, depending on design, slow river runoff and capture sediment
important for river life and delta nourishment downstream.
New engineering methods, such as sluice gates, are being incorporated into dam designs
to enhance the flush of sediments from reservoirs and minimize some of the downstream
effects of dams.
The flow regulation that results from dam construction may benefit some Mekong River
residents, but changing natural water flow patterns can be problematic for sustaining the
rich biodiversity of fish in the Mekong, particularly some species with long-distance
migratory patterns.
Migration patterns of important species can be graphically captured in the visualization to
aid impact assessments of proposed dams with increased understanding of fisheries
ecology of the Mekong.
Forecast Mekong is building partnerships with the Mekong River Commission and others
to develop advanced computer applications and visualizations that will enhance the
understanding of complex river issues and the results of hydrologic models used to
coordinate the development of water resources in the Mekong Basin from the mountains
to the sea.
The six nations that share the Mekong River will all benefit from a commonly-held
understanding of the benefits, trade-offs, and impacts of water resource development.
Scientific visualization provides a powerful tool for improving future planning and
harmonizing the development of the Mekong for people, fish, and wildlife.