Knowledge Gaps for an Interdisciplinary Water Science and Policy for Monsoon-

fed Himalayan Rivers

Jayanta Bandyopadhyay

The Summer and Winter

monsoons largely create the

precipitation patterns in the Himalaya and large parts of

Asia, including China

Normalized Melt Index (NMI) at present for

some Himalayan rivers

Rivers like Yangtse,

Huang He, Lanchang,

Tarim, Tsangpo, etc are

important Himalayan rivers for

China

Monsoon fed Huang He/Yellow River and Yangtse are crucial for water supply to densely populated areas of N China

The rivers of Nepal and India

Travel line of Brahmaputra River

River Basins Draining South Asia

The Hoover dam encouraged building of many large dams in India like the Bhakra

Total Irrigation Potential in India

020406080100120

Pote

ntia

l in

Mha

Pre

plan

1956

-61

1966

-69

1974

-78

1980

-85

1990

-92

1997

-200

2

Plan Periods

Provisioning and cultural services of the Ganges is an example of co-existence of traditional engineering and religion

Heavy sediment transport from the Himalaya to the

GBM delta is a crucial ecosystem service

Gaps in knowledge on Himalayan rivers

•In spite of the Himalaya producing the largest volume of freshwater in the world and seen as Asia’s Water Tower (Bandyopadhyay, 1995) and a number of competent independent professionals identifying important gaps, progress in the generation of such knowledge has been marginal.

Himalayan water science - paucity of data and perceptions

• Himalaya is the poorest in hydro-meteorological information. Added by the limitations of open access data, the science of Himalayan rivers has remained underdeveloped and reductionist. Generation of interdisc-iplinary knowledge is essential .

Spatial distribution of annual temperature trends in the greater Himalayan region for the period 1970–2000

Source: New et al. (2002)

The projected impacts of global change have been useful…but

• There are no effective regional climate models that address the orography and climate processes in the Himalaya. Present assessments are made by using regional climate models mainly developed in USA or Europe with limited applicability in the Himalaya

Himalayan rivers as stock or flows of water?

• The water availability from the Himalayan rivers have been calculated on the basis of the volume of water that can be stocked in the undulating parts of the uplands and mountains which has led to non-optimal use of the flows at the level of the whole basin & ecosystem services

The mangrove forests and creeks in the Sundarbans delta are degraded and highly

saline – reduced fish landing

Summer monsoon flows: are they floods or expected natural flows?

• A Himalaya specific water science has to address the monsoonal flows in Himalayan rivers as an expected hydrological process generating diverse ecosystem services with the possibility of extreme flows making substantial hydrological and geo-morphological impacts

Regular annual monsoonal flows are described as natural events or disasters

Farakka Barrage on the GangesCaused upstream-downstream disputes

over sharing of lean-flows

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Mean total rainfall (mm), DelhiMean Number of Rainy days, DelhiMean total rainfall (mm), OxfordMean Number of Rainy days, Oxford

Rainfall Pattern in Delhi (Yamuna Basin) and Oxford (Thames Basin)

The Suryakund Fall on River Bhagirathi at Gangotri 15 kms downstream of the glacial origin

Understanding of the Sediment Flows in the Himalayan Rivers

• Himalayan rivers carry sediments in large amounts. River science requires a wider understanding of the sediment dynamics. Structures like dams may not store sediments behind them but be used to generate environmental floes to flush out sediments to the downstream

An Ecologically Informed Hydro-diplomacy Can Change Things

• Concurrent with the advances in interdisciplinary water science, a new model of hydro-diplomacy, informed of the new Himalayan river science •Initially applied in the river basins, they are needed in the Himalaya as a whole, to ensure the water tower role

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