Detecting the long-term impacts from climate variability and increasing water consumption on runoff in the Krishna river basin (India)

L. M. Bouwer (1) , J. C. J. H. Aerts (1) , P. Droogers (2) , A. J. Dolman (3)

1 Institute for Environmental Studies [Amsterdam]
2 FutureWater
3 Department of Hydrology and Geo-Environmental Sciences [Amsterdam]

Variations in climate, land-use and water consumption can have profound effects on river runoff. There is an increasing demand to study these factors at the regional to river basin-scale since these effects will particularly affect water resources management at this level. This paper presents a method that can help to differentiate between the effects of man-made hydrological developments and climate variability at the basin scale. We show and explain the relation between climate, water consumption and changes in runoff for the Krishna river basin in central India. Runoff under climate variability and increasing water consumption for irrigation and hydropower is simulated for the last 100 years using the STREAM water balance model. Runoff under climate variability is shown to vary only by about 14?34 mm (6?15%). It appears that reservoir construction after 1960 and increasing water consumption has caused a persistent decrease in annual runoff of up to approximately 123 mm (61%). Variation in runoff under natural climate variability only would have decreased over the period under study, but we estimate that increasing water consumption causes about two thirds of the current runoff variability.

Domaines: Interfaces continentales, environnement; Océan, Atmosphère; Sciences de la Terre

L. M. Bouwer, J. C. J. H. Aerts, P. Droogers, A. J. Dolman. Detecting the long-term impacts from climate variability and increasing water consumption on runoff in the Krishna river basin (India). Hydrology and Earth System Sciences Discussions, 2006, 3 (4), pp.1249-1280. ⟨hal-00298722⟩