By Umar Musa Umar
Rainfall is an important climatic element that determines the potentiality of a location to excel in food production and economic growth.
Crop production, animal husbandry, aquaculture, forestry, and plantation agriculture can never be successful where there is a capricious supply of water.
Geographically, all waters on land surfaces are stored primarily in the atmosphere and are released to the ground surfaces through rainfall which is utilized by all living organisms.
Part of rainwater that falls on the surface is stored by the underground natural storage media known as “aquifers”. Thus, rainfall is the pillar of human existence on the planet earth.
NIHSA warns on impending flood in some states
It provides valuable ingredients for plant growth therefore, indispensable for agricultural production. Where rainfall is sufficient for crop production, people pleat from all over the world to benefit from such a favorable farming-enabling environment.
The early human civilization was directly connected with either humid tropical climate (where rainfall is abundantly available) or along floodplains (where underground water aquifers are rich)
Kano is the largest city in northern Nigeria and one of the business hubs in Sub-Saharan Africa.
It is famous for its favorable climate, fertile soil, and relatively plain topography that supports the large production of both cash and food crops.
Historically, the second set of migrants that formed the present-day kano in the 9th century “Madatai community” were farmers that invade Kano in their quest for fertile land and favorable climate suitable for agriculture.
Kano is blessed with a moderate rainfall of about 884.4mm (Olofin, 1987) which is steadily distributed within six months of every year (i.e. May to October). The steady nature of rainfall in the region favored the profitable form of agriculture known as rained cultivation to dominate the occupation of the area.
The total annual rainfall in Kano for the past 60 years has an irregular pattern and if the irregularity persists, the region may undergo severe catastrophe.
Many pieces of research investigate the variability of rainfall in the state and other northern states of the country. Apart from the 1972 Kano drought, the rainfall records of 45 years (1950- 1995) maintain a steady pattern of a moderate amount (700mm – 1000mm) with an insignificant variation.
That is to say, the rainfall is distributed among the six months of every year (May – October) August being the month with the peak downpour. But from 1996 to date, Kano has been experiencing rainfall variability and fluctuation both in amount and duration.
It has been established that the active rainfall in the state for the last two and a half decades did not only increase in amount but decline in the duration from six months to less than four months.
Many people assume that climate change can only result to decrease in rainfall and consequently cause drought and desiccation in the area. Of course, climate change causes rainfall shortage, drought, and desertification, however, it can also cause an increase in rainfall which may eventually upshot flooding.
Taking kano as a case, the rainfall increases in amount but reduces in duration which means more rainfall would be concentrated in a small period of time.
This will produce intricating problems ranging from recurrent drought and flooding as well as a threat to food resources which leads to famine and starvation and poverty.
Draught is the first disaster that gradually impedes the success of commercial farming not only in Kano but in many northern states of the country.
People are unaware of the silent draught taking place in the states. In Kano state, the rainy season starts usually in May of every year but recently, even if the rain starts in Mid-May it seizes for a month or two before an active rain continues to drop.
Within this drought period, crops may wilt and die for insufficient moisture in the soils. Rainfall offset in Kano also deviates from its normal as sometimes the rain stops much earlier such as early September as in 2007, than the normal (i.e. October).
However, the rain may also set-off longer the normal as evident from 2010 and 2019 where rainfall extended to mid-November.
The flood occurred in kano due to the aforementioned changes in the onset, offset, and frequency of rainfall. The rainfall that is distributed within six to seven months is now concentrated within three to four months.
Kano has also been experiencing an increase in its amount from a mean of 884.4mm to over 1000mm per year, the rainfall usually causes flooding in the state.
The reduction in the rainfall regime when coinciding with the increase in the rainfall amount causes widespread flooding not only in Kano state but in most northern states.
Recently, the National Emergency Management Agency (NEMA) predicted about 102 local governments that would be affected by flooding this year, out of which 20 are from Kano state.
In addition to the changes in frequency and duration of rainfall, flooding in kano may also be attributed to other factors. Kano is among the fast-growing cities in Nigeria, the urbanization rate is very high resulting to increase in Percent Impervious Surface Area (%ISA) such as concrete and cemented surface, tarred roads, etc.
This couple with improper and blocked drainage channels results in urban flooding in the metropolitan areas of kano state.
While overflow of the nearby streams, dams, and ponds due to high rainfall causes flooding in the outskirt of the metropolis.
The above impact of rainfall anomaly can result to a serious threat to food resources as they are directly connected with the availability of water.
In Kano state crops such as millet need to be grown at the beginning of the wet season. Thus, if there’s minor draught after the sowing millet, there would be serious damage.
Some other crops have specific water requirements (e.g. rice and wheat) and need to be submerged in water all the time. Due to unreliability and unsteady rainfall in Kano State, rice farmer for over 10 years used the watering machines to water their crops in the midst of rainy season to avoid wilting and damages of their crops.
It is quite sure that issues related to climate change could not be tackled or eradicated completely but certain measures could be adopted to lessen its ramification.
Tree planting (afforestation/reforestation) to restore the already destroyed vegetal cover should be of utmost importance.
City orchard and gardens that have become vanished should be restored across the city landscape. Other green city practices such as grass/green roofing etc. must also be put in place.
This would restore the climate of the area. For the urban flood, all drainages must be cleared regularly, bare surfaces should be left greener with grasses while concrete/cemented surfaces should be replaced with interlocking.
Finally, dredging major streams and rivers as well as demolition of all structures constructed on river courses.
Umar Musa Umar wrote this from Kano and his (Area of interest: Geography, Climatology, GIS, Remote Sensing, Environmental issues)
Dept. of Geography,
Yusuf Maitama Sule University Kano.
Phone No: 08035594946
Email: umarsurely@gmail.com
