It is recognized that there is no universally accepted definition of drought due to the wide variety of sectors affected by drought as well as its diverse spatial and temporal distribution. Moreover, it is well known that water scarcity and droughts constitute a specific scientific field of hydrology and water resources. This area of study is currently receiving significant attention, which is primarily due to climate change, among other reasons. In addition, drought exhibits a number of key features, such as its non-structured effects, or its slow onset.
Desertification must be considered as a global problem that requires direct actions and measures. Natural and anthropogenic causes jointly lead to land degradation and eventually to desertification, a phenomenon which occurs in arid, semiarid and dry subhumid areas.
Furthermore, extended drought periods may cause soil exposure and erosion, land degradation and finally desertification. Several climatic, geological, hydrological, physiographic, biological and human factors contribute to desertification. The methodological procedure presented is based on remote sensing tools for use in the quantitative classification of desertification severity over a watershed with degraded groundwater resources.
The scientific community must also face, especially under water penury conditions, the supply of greenhouse agriculture. Specifically, we must undertake a reliability analysis of rainwater harvesting tanks for use in irrigation water. This challenge is examined in paper of Londra et al., 2021.
Rainwater harvesting is an ancient water management practice that has been used to cover potable and non-potable water needs. In recent years, this practice has been considered as a promising alternative and a sustainable source of water to meet irrigation needs in agriculture in arid and semi-arid regions. Using the daily water balance model, the size of rainwater tanks for irrigation use was investigated in greenhouse settings for begonia and tomato cultivations in two regions of Greece.
The major droughts in the United States that have heavily impacted the hydrologic system and negatively affect energy and food production are analyzed in the paper of Kokikot and Omitaomu. An improved understanding of historical drought is critical for accurate forecasts. Data from global climate models cannot effectively evaluate local patterns because of their low special scale. This research leverages downscaled (~4 km grid spacing) temperature and precipitation estimates from global climate models’ data to examine drought patterns. The high spatial scale at which the analysis was performed allowed us to uncover significant local differences in drought patterns. This is critical for highlighting possible weak systems that could inform adaptation strategies, as in the energy and agricultural sectors.
The agricultural sector is vulnerable to extreme phenomena such as droughts, particularly in arid and semi-arid environments and in areas where water infrastructure is limited. Devising preparedness plans, including means for efficient monitoring and timely identification of drought events, is essential for decision making on drought mitigation and water management. In the paper of Tigkas et al., two new indices, Agriculture Standardized Precipitation Index (aSPI) and the effective Reconnaissance Drought Index (eRDI), were incorporated in the Drought Indices calculator (DrinC) software. This enhances the applicability of the software, especially for the characterization of agricultural drought.
Sharma and Panu presents a procedure for the estimation of drought magnitude (M), which then forms the basis for estimating the drought duration or length (L). The drought magnitude (M) and the length of the critical period (Lcr) are estimated using the concept of behavior analysis prevalent in the hydrological design of reservoirs. The performance of the procedure to estimate drought length was found to be satisfactory up to the truncation level of Q75, whereas the estimation of drought magnitude was rated as good.
Drought poses significant risks in irrigated crop production, which accounts for a large share of global freshwater use. Given its key role in the production of food, feed and fiber crops, there exists a need for policy measures to prevent and mitigate the impact of drought on irrigated agriculture. The paper suggests that the design of drought policy should consider actual former behavior in response to water scarcity.
A Guest Editorial