TY - JOUR
T1 - Irrigation area, efficiency and water storage mediate the drought resilience of irrigated agriculture in a semi-arid catchment
AU - Lankford, Bruce
AU - Pringle, Catherine
AU - McCosh, Jon
AU - Shabalala, Mlungisi
AU - Hess, Tim
AU - Knox, Jerry W.
PY - 2023/2/10
Y1 - 2023/2/10
N2 - We examined the effects of hydrological variables such as irrigation area, irrigation efficiency and water storage on the resilience of (mostly commercial) irrigated agriculture to drought in a semi-arid catchment in South Africa. We formulated a conceptual framework termed ‘Water, Efficiency, Resilience, Drought’ (WERD) and an accompanying spreadsheet model. These allow the resilience of irrigated agriculture to drought to be analysed via water accounts and a key resilience indicator termed Days to Day Zero (DDZ). This represents the number of days that a pre- and within-drought supply of catchment water available to irrigation is withdrawn down to zero in the face of a prolonged drought. A higher DDZ (e.g. >300 days) indicates greater resilience whilst a lower DDZ (e.g. <150 days) signals lower resilience. Drought resilience arises through land and water management decisions underpinned by four types of resilience capacities; absorptive, adaptive, anticipative and transformative. For the case study, analyses showed that irrigators, with currently approximately 23,000 ha under irrigation, have historically absorbed and adapted to drought events through construction of water storage and adoption of more efficient irrigation practices resulting in a DDZ of 260 days. However, by not fully anticipating future climate and water-related risks, irrigators are arguably on a maladaptive pathway resulting in water supply gains, efficiency and other practices being used to increase irrigation command areas to 28,000 ha or more, decreasing their capacity to absorb future droughts. This areal growth increases water withdrawals and consumption, further stresses the catchment and reduces future DDZs to approximately 130 days indicating much lower drought resilience. Our approach, supported by supplementary material, allows stakeholders to better understand the resilience consequences of future drought in order to; reconcile competition between rising water demands, consider new water storage; improve agricultural and irrigation planning; and enhance catchment governance.
AB - We examined the effects of hydrological variables such as irrigation area, irrigation efficiency and water storage on the resilience of (mostly commercial) irrigated agriculture to drought in a semi-arid catchment in South Africa. We formulated a conceptual framework termed ‘Water, Efficiency, Resilience, Drought’ (WERD) and an accompanying spreadsheet model. These allow the resilience of irrigated agriculture to drought to be analysed via water accounts and a key resilience indicator termed Days to Day Zero (DDZ). This represents the number of days that a pre- and within-drought supply of catchment water available to irrigation is withdrawn down to zero in the face of a prolonged drought. A higher DDZ (e.g. >300 days) indicates greater resilience whilst a lower DDZ (e.g. <150 days) signals lower resilience. Drought resilience arises through land and water management decisions underpinned by four types of resilience capacities; absorptive, adaptive, anticipative and transformative. For the case study, analyses showed that irrigators, with currently approximately 23,000 ha under irrigation, have historically absorbed and adapted to drought events through construction of water storage and adoption of more efficient irrigation practices resulting in a DDZ of 260 days. However, by not fully anticipating future climate and water-related risks, irrigators are arguably on a maladaptive pathway resulting in water supply gains, efficiency and other practices being used to increase irrigation command areas to 28,000 ha or more, decreasing their capacity to absorb future droughts. This areal growth increases water withdrawals and consumption, further stresses the catchment and reduces future DDZs to approximately 130 days indicating much lower drought resilience. Our approach, supported by supplementary material, allows stakeholders to better understand the resilience consequences of future drought in order to; reconcile competition between rising water demands, consider new water storage; improve agricultural and irrigation planning; and enhance catchment governance.
KW - Adaptation
KW - Fruit production
KW - River basin
KW - South Africa
KW - Water accounting
UR - http://www.scopus.com/inward/record.url?scp=85142875314&partnerID=8YFLogxK
U2 - 10.1016/j.scitotenv.2022.160263
DO - 10.1016/j.scitotenv.2022.160263
M3 - Article
VL - 859
JO - Science of the Total Environment
JF - Science of the Total Environment
SN - 0048-9697
IS - Part 2
M1 - 160263
ER -
