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Hydrometeorological risk assessment for crops in Chile

IWRA World Water Congress 2017 - Cancun Mexico
A. Bridging science and policy
Author(s): Gabriel Candia
Roberto Ponce
Diego Rivera
Alex Godoy-Faúndez

Gabriel Candia
FONDAP CRHIAM, CiSGER, Facultad de Ingeniería, Universidad del Desarrollo
Roberto Ponce
FONDAP CRHIAM, CiSGER, Facultad de Economía y Negocios, Universidad del Desarrollo
Diego Rivera
FONDAP CRHIAM, Facultad de Ingeniería Agrícola, Universidad de Concepción
Alex Godoy-Faúndez
FONDAP CRHIAM, CiSGER, Facultad de Ingeniería, Universidad del Desarrollo

Keyword(s): Hydrometeorological, risk assessment, climate change, crops, Chile. PEER, Pacific Earthquake Engineering Center


Based on meteorological forecast for the next 50 years, crops are highly vulnerable to climate change effects. Large precipitations in the northern desert, and extended drought in south-central Chile seriously impact farmers and the industrialized agriculture. In the last 40 years, over 180.000 people in Chile have been affected by severe weather conditions and the reported losses in the agricultural sector exceeded US$ 1,000 million. These figures are due in part to inadequate risk reduction strategies, which place the emphasis on post-disaster reaction rather than a long-term scientific-based risk management.

A key element for risk analysis is aggregating the information of the several risk constituents, namely, natural hazard variables, system response variables, and decision making variables. This study presents a platform for hydro-meteorological risk assessment on maize and sugar beet in Chile, two crops with a market share of over 65% of the seed industry produced in Chile. The platform uses state of the art models for crop production, empirical based natural hazard models, and a rational treatment of uncertainties. The computation of risk is based on the risk assessment methodology developed by the Pacific Earthquake Engineering Center PEER to model seismic risk in infrastructure. The main goal of the platform is to aid researchers and decision makers to quantify risk in terms of annual rates of exceedance of relevant risk decision variables such as dollar losses, crop yield deficit, recovery time, etc.

The platform, developed as a MATLAB user interface, is structured in three modules. The first module allows to determine basic weather variables at any point in the territory, using daily records from precipitation and temperature gauges, and data interpolation using different techniques (SBE, IDWM, CCWM, MLR), which enables to model the epistemic uncertainty. This information is used to compute annual rates of exceedance and probability distribution functions for daily precipitation and daily temperatures.

The second module uses the FAO Penman-Monteith equation to characterize the maize and sugar beet response to water stress. The platform evaluates the crops evapotranspiration from standard meteorological data such as precipitation, temperature, humidity and wind speed, and is currently the standard for crop production. Crop parameters specific to local conditions and the random variability of key parameters is also taken into account. The third module deals with the evaluation of risk variables; it computes the relative reduction in crop yield as a function of the reduction in evapotranspiration and the estimation of the market value of each crop.

The potential uses of the platform range from the quantification of climate risks, the managing of water resources, and design of mitigation strategies. This approach will aid farmers and decision makers to quantify risks and its willingness to accept losses in their annual planning year by year, without complex climatic models.

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