Now is the time to harvest rainwater

18 January 2021 | Agriculture

The previous and current rainy seasons in Namibia has given a sigh of relief to many farmers and is an indication that the country is gradually recovering from the impact of the long drought spell experienced over a period of about seven years.
The current season is characterised by higher daily rainfall figures and in some parts of the country or regions, the //Kharas and Hardap amongst others, the figures have surpassed annual averages even before the peak rainy months, mainly February and March.
This is good for the soil that has been desiccated for a long time due to drought and the extreme heat waves experienced in many areas of the country. It is therefore advisable that farmers take advantage and make optimal use of this rain by reducing excessive runoffs through harvesting rainwater.
Many farming areas are challenged by the availability of water and the functionality of water infrastructures, which in turn hampers their productivity, be it crop or livestock.
Almost all big rivers in the country are running, filling up the dams, the soil is rehydrated, flood plains are filled, and very importantly, underground water is replenished. This could reduce the pressure on underground/borehole water and it is an opportunity for farmers to improve their water storage facilities or increase the capacities to store enough water for use during the time of scarcity or in the dry season.
Most of the country’s large dams are filled-up to optimal capacities, and this is also an opportunity to establish seasonal agricultural projects around these dams to reduce the food supply gaps in the country.

Harvesting
Rainwater harvesting is an old technique of water conservation where rainwater is collected using various methods or structures to capture the water.
Rainwater can be used for several household needs such as laundry, irrigation, bathing, cleaning, and for livestock.
The most common methods of harvesting include catching water from buildings’ rooftops using gutters to channel water into storage drums or tanks, and by channelling or diverting runoff water towards a pond or earth dam, and even towards a crop field to irrigate the crops or rehydrate the soil. Harvesting methods are simple and cheap, thus they can be adopted at any scale especially in rural areas were water demand and supply are mostly a challenge.
On that, individual farmers or even the community can set up rainwater harvesting infrastructure at their water points and have additional storage tanks or use rainwater to fill up their reservoirs to compliment the borehole water supply.

Advantages
The advantages of rainwater harvesting include that it conserves water, it is cost-effective, increases water supply, saves cost of water supply, and conserves the soil by reducing runoff and erosion.
The techniques to reduce runoff are also aimed at facilitating water infiltration into the soil by obstructing or reducing the speed of flow, thus increasing the moisture content and water holding capacity of the soil. This can be done on crop fields and grazing areas.
For example, the flow of water can be obstructed or slowed down by laying various local materials such as rocks, tree branches, or logs across the direction of the flow which will then allow water to settle and infiltrate in the soil.
With good rainfall prospects for the rest of the season, Namibians should take advantage and invest in rainfall harvesting modalities to increase sustainable food production.
During the Covid-19 pandemic, food scarcity or supply will be of concern, thus in an effort maintain food-self-sufficiency, every farmer should turn the land at their disposal into food baskets for own consumption and income generation.
In conclusion, prioritising and enhancing agricultural production at all scales is the only tool to alleviate poverty, create employment, develop rural areas and reduce rural-urban migration amongst others. This requires a sustainable network of support from all agricultural role players including retail shops (supermarkets) to be able to facilitate accessibility to information, capacity building, finance, production inputs and the markets.
• This article was compiled by Erastus Ngaruka, Technical Advisor (Livestock & Rangeland), Agribank.