Botswana is referred to, or regarded as a dry country. It has been very hot of late that the temperatures are reaching at least 40 degrees Celsius in most parts of the country.
It is not only this year, even last year the country experienced inadequate amounts of rainfall which impacted badly on the agriculture sector hence lowering the economy of Botswana. We also saw dams including Gaborone dam drying up, which at this stage is now on the brink of becoming a pathetic ploughing field.
The situation has prompted young upcoming Batswana scientists to think of other measures to arrest the situation. One of the measures includes a process called CLOUD SEEDING, which is a process of making artificial rain. Science and technology has advanced so much that there is nothing left undone or unexplored. People have reached the skies, literally and famines and droughts are strategically given several appropriate solutions that could drive these hindrances away.
One of them being cloud seeding. During acute weather conditions where there is a grave scarcity of water, there have been so many deaths that occurred across the country affecting both domestic and wild animals due to severe scarcity of water. Recently the situation has gone from bad to worse in villages and towns where people can go for five or more days without a single drop of water from the taps.
The need to develop and improve rain-making techniques in terms of design, operation, monitoring and evaluation by giving them a more scientific character is today’s need.
This includes using computers to study cloud formations and help the rainmaking operations achieve the goals of the project.
The role of weather modification, or rainmaking, is an important component in water resources management. The process involved in artificial rain-making involves three easy-to-understand stages. The first stage is agitation. That is using chemicals to stimulate the air mass upwind of the target area to rise and form rain clouds.
The chemicals used during this stage are calcium chloride, calcium carbide, calcium oxide, a compound of salt and urea, or a compound of urea and ammonium nitrate.
These compound are capable of absorbing water vapour from the air mass, thus stimulating the condensation process.
The second stage is called building –up stage. Here the clouds mass is built up using chemicals such as kitchen salt, the T-1 formula, urea, ammonium nitrate, dry ice and occasionally also calcium chloride to increase nuclei which also increase the density of the clouds.
In planning every stage a high degree of expertise and experience is required, in selecting the types and amounts of chemicals to be used, while taking into consideration weather conditions, topographical conditions, wind direction and velocity as well as the location or delimitation of the area for chemical seeding.
Several other ideas are also involved in rainmaking ie, Rockets containing rainmaking chemicals can be fired into the clouds either from the ground or from aircraft.
A jet of rainmaking chemical is shot from a highly pressurised canister directly into the cloud base, so as to coerce clouds which normally hang above mountain tops to cluster up and rain on mountains or their slopes.
Some of the advantages of cloud seeding may among others include: increase of precipitation, crops grow without any hindrance, Economic improvement, when naturally dry grass areas receive rain due to cloud seeding, there won’t be any fear of droughts and can also attract tourists.
The whole objective of cloud seeding is to enhance rainfall, increase recharge, increase soil moisture and lessen the demand for surface and groundwater resources. Of course these processes may be having their disadvantages as well like being expensive to carry out , chemical deposits that may be harmful to living organisms if done often, but l bet they will not overcome the good.
The first cloud seeding was conducted in 1946 when two chemists at General Electric Research Laboratory in New York did an interesting experiment. Irving Langmuir and Vincent J Schaeter discovered that dry ice pellets could help form big ice crystals in a cloud.
The cloud in their experiment consisted of water droplets in a deep freeze box. As the pellets feel through this super-cooled layer of clouds, water droplets present in the cloud froze and the ice crystals formed and grew in size till they became so large that they fell to the bottom of the freezer. And that was the first ever cloud seeding. We have no choice but to experiment this process to fight this drought.
Gaolatlhe Monjo Modise