Development of the Agricultural Water Demand and Supply Drought Index (AWDSDI) in Evaluating Daily Agricultural Drought in Small Administrative Districts

Abstract

Drought is caused by a long period of lack of rainfall and water resources, and has a great impact on the life and ecosystem of both humans and animals. It is particularly important for the agricultural sector, which is closely related to food security. Global warming, urbanization, and industrialization have led to a gradually increasing demand for agricultural water. In response, Korea has steadily developed its agricultural water sources to reduce rising damage to the agricultural sector due to climate change. The severity of drought is evaluated by using meteorological, agricultural, hydrological, and socioeconomic drought indexes. The agricultural drought index is evaluated using soil moisture and crop dryness, and the hydrological drought index is evaluated based on water shortage by comparing demands with water resources available for supply, such as rivers and groundwater, reservoirs and dams. However, these methods were found to over- or under-estimate the relatively low sensitivity of agricultural water as they assess the shortage of water for life, industry, and agriculture. Therefore, in this study, we developed the Agricultural Water Demand and Supply Drought Index (AWDSDI), which evaluates agricultural drought by analyzing water supply systems such as agricultural reservoirs, pumping stations and drainage, groundwater systems, and demands for agricultural water. In order to review the applicability of the developed drought index, AWDSDI was applied to 32 Eps and Myuns in three cities, including Jincheongun, Changnyeonggun, and Jangseonggun in the period June-August 2017, when drought damage was significant. It was found that AWDSDI reproduced the daily agricultural drought well in small administrative districts such as Eps and Myuns. In addition, in order to verify the developed drought index, the evaluation results of AWDSDI, the previously developed agricultural drought index and the hydrological drought index were compared together. The comparison found that the AWDSDI reproduced the drought period and drought depth in 32 Eps and Myuns in three cities better than previously developed drought indices.