General Information

In previous decades, natural resources have deteriorated at a greater rate, which in turn has created conditions of increased vulnerability for the population towards natural phenomena such as droughts.

Drought is defined as insufficient water availability over prolonged periods of time in extensive areas causing severe deprivations.

It has an impact on food production, life expectancy and economic performance over large regions or entire countries. Drought is a recurrent characteristic of climate. It happens virtually in almost all climatic zones, and its characteristics vary significantly between regions. Drought differs from “dryness” in that a drought is temporary; dryness is a permanent characteristic of regions with low rain fall.

A working definition of drought could be: a notable temporary decrease in available water and humidity, below the normal amount for a given period.

The following are essential components for such a definition:

1. That the decrease is temporary (if the decrease were permanent, “dry” or “arid” would be more suitable terms).

2. That the decrease is significant.

3. That the decrease is defined with respect to a “norm”.

4. That the period used as a bases for the “norm” is specified.

The way in which the “norm” is defined is extremely important.  Points 3 and 4, therefore require a more detailed explanation.

The “norm” can be defined in one of the following two ways:

a. Technically: for example, a drought could be declared if the water availability falls below 80% of the average of the available water over the previous 20 years. However, given the natural fluctuations in climatic conditions, the period of time selected for the calculation of the average can be deceptive.

b. Culturally: based on the level of water availability considered to be “normal” by the society.   All societies tend to establish their own socioeconomic systems according to their own perception of what is normal precipitation, and this perception is of greater importance to societies than what has recently been observed. For example, after ten consecutive years of greater than normal rainfall, a society is accustomed to that level of rainfall and the first year that there is a normal level of rain, they might consider there to be a drought. 

Types of Drought:  There are three different types of droughts:

• Meteorological: involves a reduction in precipitation in a certain period (day, month, season, and year) below a determined amount, normally defined as some proportion of the long term average for a specific period of time. Its definition only includes precipitation data. Precipitation data should be used and aggregated with care. 

• Hydrological: refers to a decrease in aquatic resources (river flow, lake levels, underground springs, water-bearing mantles) below a predetermined level for a given period of time. Its definition only incorporates data of availability and consumption rates based on the normal supply of the system (domestic, industrial and agricultural use).

• Agricultural: refers to the impact that meteorological and hydrological droughts have on this particular sphere of human activity.  Crops  require very specific conditions of temperature, humidity and nutrients during their growth in order to reach their maximum development. If the availability of humidity (or any other factor) is inferior to the required optimal level during development, then their will less growth and the production and yield will be reduced.

Possible Measures of Prevention and Mitigation

• Diversification strategies for production of crop varieties with greater resistance and greater yield.

• Investigate techniques of humidity conservation or techniques that contribute to reducing the hydro deficit that results from the drought.

• Promote the implementation of projects that include water reservoirs, artisan irrigation, not burning the ground, the incorporation of ground scrubs and other practices that are friendly to the soil resource.

• Educate on the importance of good water and tree resource management practices,  and on the protection of river basins and micro river basins.

• Train community organizations about the importance of Risk Management Development Plans, in order to identify specific causes of physical, ecological and social vulnerabilities, as well as the management of weather predictions, in order to know what alternatives can be considered in before these phenomena happen.
  

Solutions

Recommendations for the prevention and mitigation of drought can be divided into those related to macro-character measures, destined to influence government policies, and those of a micro-character, destined to alter the ecological conditions and agricultural practices of affected zones.  Many micro-character recommendations need to be developed by the Government, however, they can also be comprised of recommendations from international cooperation agencies’ strategies.

Measures for Mitigating the Effects of Drought and for Maintaining Food Security in the Face of an Emergency

• Stabilization of prices

• Food subsidies

• Job creation programs

• Generalized distribution of food

• Food supplement Programs

• Special programs for pastoral farmers and cattle producers

• Complementary water supply programs

• Complementary health programs.

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Compilation taken from articles:

Romeo, Bernal. Las Sequías: Desastres Considerados Como “Pequeños” pero Grandes en su Importancia. Revista EIRDInforma, no. 4, 2001

Segura Sánchez, Claudio.
La sequía: el desastre de mayor impacto en la humanidad. Revista Biocenosis, no.5. 1997

Grupo de Investigación, Ojos Negros.
Tres problemas de desarrollo sustentable
en el Valle de Ojos Negros, Baja California, México.
En: http://tresproblemas.sdsu.edu/tres_problemas_sequia04.html