Incorporate rainwater harvesting in building designs

By Simon Mone

trueAchieving food and water security are among the crucial development challenges that Ugandans are going to deal with for some time.

Since water is a basic need, consideration for reservation should be taken seriously for use during the drier months. Water harvesting ought to be included in planning for developments of all residential houses.

Harvesting and storage of water is required to take care of population growth, increased urbanisation, environmental degradation, dry conditions, water point conflicts that are all continuously increasing stress on available water sources.

According to projected statistics, by 2025, two thirds of the World’s population could be living in severe water stress conditions. It means that human dependency on available water sources are going to be tested to the limit.

It is a vital reason to manage sparingly scarce waters so that humanity can depend on for a variety of future uses including for sustainable food production. Agriculture is said to utilise about 70% of the World’s freshwaters through irrigation.

Increasing population plus increasing and changing diet is expected to increase food demand. Based on this current use pattern, agricultural water utilisation is expected to increase to provide food for the increasing population.

The impacts of environmental degradation and climate change continue to show in oceans and mountain tops. Rapid glaciers are melting and snow packs are decreasing. Water flow to lower areas is slowly becoming inadequate.

In the end, communities that depend on those sources will be in dire need of alternative water. Climate change effects added to depletion of available water sources could increasingly restrict access to safe water and sanitation and render food security unachievable.

The likelihood of climate change sabotaging rain-fed agriculture is high, thereby hindering crop production. Strong storms that have characterised the rainy seasons could cause more flooding across the country, displacing populations and their livelihood.

These unpredictable rains and limited knowledge among communities to reserve water will most likely hamper crop agriculture. Therefore, during the dry seasons, instead of utilising stored water, many communities will have no option.

Crops will then dry up. Cattle keepers will continue to have their herds die owing to lack of water. To ensure that sufficient water is available to meet community’s needs of crop and livestock agriculture, therefore, let us harvest the rains.

Instead of going for expensive options such as drilling boreholes, a more low cost alterative could be to provide rain run-off catchments that trap and reserve water. This can assure crop and livestock agriculture throughout the year, especially during the two dry spells from January to February and August to September.

Low-cost efficient technologies exist for rainwater harvesting. One that is cost effective and is applicable without difficulties is achieved by lining polythene material around the walls of an excavated underground tank. Provided the tank is big enough, storage tanks can reserve enough water for big crop plantations and livestock.

An underground tank costs less than sh100,000 which most people should afford. More expensive technologies include storage tanks made of ferro-cement material or bricks or plastic.

A well constructed tank is capable of collecting 90,000 litres of water. The Government should introduce a policy to require the Ministry of Lands, Housing and Urban Development to encourage residents to incorporate rainwater harvesting in designs of residential housings. Doing this will increase access to clean and safe water and also food security.

The writer is a civil engineer