Managing scarce water resources in Asia: The nature of the problem and can remote sensing help?

Abstract

Water demands are outstripping supplies in many parts of Asia and causing conflicts, especially as rapidly urbanizing and industrializing areas compete with more traditional agriculture on alluvial plains near expanding metropolises. The environment is increasingly being seen as a legitimate and important user of water, often in competition with irrigation, domestic, industrial, hydropower and community uses of water. Any future scenario requires an improvement in water productivity, especially in agriculture. Surface and ground water supplies are not well regulated owing primarily to a weak knowledge base, analytical capacity in addition to a number of traditional institutional, governance, political and other factors. Water policy makers have, therefore, to work out strategies for integrated water and environmental management, which rely on a proper knowledge base of the basin hydrological and pollution conditions. Examples from various countries in Asia are elaborated in this paper to demonstrate how spatially distributed evapotranspiration data from remote sensing, in conjunction with other key data, can help to build the knowledge base for integrated basin scale water management. Remote sensing is not a solution, but it provides key data that is difficult to access by conventional data collection methods.

Thermal Remote Sensing of Drought and Evapotranspiration

“…Remote sensing provides an objective, synoptic assessment of water availability for strategic planning at the basin scale. In collaboration with the World Bank, TIR-based ET has been used in Asia to evaluate groundwater withdrawals and reduce over abstraction, determine optimal diversions for irrigation and leaching of saline soils, assess wateruse efficiency of crops, and estimate runoff in ungauged basins [Bastiaanssen and Harshadeep, 2005].…”

Eos, Transactions, American Geophysical Union Volume 89, Number 26, 24 June 2008

“…Remote sensing provides an objective, synoptic assessment of water availability for strategic planning at the basin scale. In collaboration with the World Bank, TIR-based ET has been used in Asia to evaluate groundwater withdrawals and reduce over abstraction, determine optimal diversions for irrigation and leaching of saline soils, assess water-use effi ciency of crops, and estimate runoff in ungauged basins [Bastiaanssen and Harshadeep, 2005].…”

Uso De Dados De Precipitação Obtidos Por Sensoriamento Remoto Em Um Modelo Agro-Hidrológico

“…Também é importante mencionar o uso de dados obtidos a partir de sensoriamento remoto na estimativa da evapotranspiração real, sendo esta obtida indiretamente a partir do fluxo de calor sensível e observações de dados climáticos por meio de algoritmos de balanço de energia superficial calculados em cada grade. Um algoritmo muito utilizado neste caso é o SEBAL (BASTIAANSSEN et al, 2005), o qual estima fluxos de calor latente superficial a partir do albedo, reflectância e temperatura superficiais que atingem os sensores do satélites, tais como MODIS e LANDSAT.…”

“…Para aplicações em outorga de água para irrigação e desenvolvimento de calendários agrícolas, a evapotranspiração real e as precipitações obtidas por satélite podem ser muito úteis para estimar o estresse hídrico e avaliar a disponibilidade de água (BASTIAANSSEN et al, 2005). Droogers e Bastiaanssen (2002) apresentaram resultados de um estudo realizado em uma região do oeste da Turquia com os cultivos de uva e algodão.…”