Details

Autor(en) / Beteiligte

• Wada, Yoshihide
• van Beek, L. P. H.
• Bierkens, Marc F. P.

Titel

Nonsustainable groundwater sustaining irrigation: A global assessment

Ist Teil von

• Water resources research, 2012-06, Vol.48 (6), p.n/a

Ort / Verlag

Washington: Blackwell Publishing Ltd

Erscheinungsjahr

2012

Link zum Volltext

Quelle

EZB-FREE-00999 freely available EZB journals

Beschreibungen/Notizen

• Water used by irrigated crops is obtained from three sources: local precipitation contributing to soil moisture available for root water uptake (i.e., green water), irrigation water taken from rivers, lakes, reservoirs, wetlands, and renewable groundwater (i.e., blue water), and irrigation water ed from nonrenewable groundwater and nonlocal water resources. Here we quantify globally the amount of nonrenewable or nonsustainable groundwater ion to sustain current irrigation practice. We use the global hydrological model PCR‐GLOBWB to simulate gross crop water demand for irrigated crops and available blue and green water to meet this demand. We downscale country statistics of groundwater ion by considering the part of net total water demand that cannot be met by surface freshwater. We subsequently confront these with simulated groundwater recharge, including return flow from irrigation to estimate nonrenewable groundwater ion. Results show that nonrenewable groundwater ion contributes approximately 20% to the global gross irrigation water demand for the year 2000. The contribution of nonrenewable groundwater ion to irrigation is largest in India (68 km3 yr−1) followed by Pakistan (35 km3 yr−1), the United States (30 km3 yr−1), Iran (20 km3 yr−1), China (20 km3 yr−1), Mexico (10 km3 yr−1), and Saudi Arabia (10 km3 yr−1). Results also show that globally, this contribution more than tripled from 75 to 234 km3 yr−1 over the period 1960–2000. Key Points Global assessment of non‐sustainable groundwater ion for irrigation Non‐sustainable groundwater globally contributes 20% to irrigation Increasing dependency on non‐sustainable groundwater in recent years