Trenches help semi-arid farmers perfect water harvesting

Behind year round guaranteed yields in the semi arid Laikipia district, is a novel idea where farmers are digging trenches that capture run off water during rainy seasons, which is then slowly released to the field below over long periods, helping keep crops alive during dry spells in a classic example of rainwater harvesting gone successful.

Known as dead level contours the trenches, around 50cm deep and 1m wide, are dug by farmers living on undulating slopes. The rainwater and top-soil running down the field is captured. Over the next few weeks, the water slowly seeps from the trench into the soil beneath, irrigating the section of fthe ield below the trench and keeping plants alive.

Laikipia experiences prolonged spells of drought, followed by heavy rainstorms with both being bad news for farmers, starving crops and livestock of water, and then washing away vital top-soil, especially when fields are on a slope. 

Dead level contours which were introduced to farmers by one of their own scientist, Dr.Wellingtone Sila, have attracted over 1000 households in especially Rumuruti and Lamuria areas where majority of farmers had abandoned crop cultivation on prolonged drought and erratic weather. But digging the contours is both involving and intensive which has seen farmers form groups to dig as many contours in as many households as possible.

A typical quarter piece of land has about 4 contours. “So we have an agreement to go from farm to farm as a group to dig the trenches. Most of the farmers here have on average one acre. We divide ourselves in groups of 12 and in a day we cover two farms. Our ultimate goal is to get as many farmers as possible into this idea to ensure we are self sufficient food wise and also go big on agribusiness,”said Gathekia Watwiri who cordinates the digging of the trenches.

When digging the contours, farmers use measuring sticks for precision. The sticks are accurate because they direct them as to where the water should flow towards. “We do this because we do not want to make mistakes with the digging of contours. So the length of the stick tells us how far the water will flow and how much water the contour can hold,”said Gathekia. “When the first rains start at around March I plany my first crops, when the rains come again around July the water still holds, and even as I wait for the next set of rains in October I wont interupt my farming because the water will still be intact in the soil. It costs me nothing but it gives me food across the year,”said Beretta Nyakio a widow who was among the pioneer farmers to dig the contours.

Beretta who says she has now tripled yields by ensuring she has year round harvests, rain or shine, says the ultimate answer for any farmer seeking to produce uninterrupted produces is in investing in these contours. “I am now even toying with the idea of diversifying into fresh produces something no one has ever thought about due to the harsh climatic conditions,”she said.

According to the Southern and Eastern Africa Rainwater Network (SearNet) hosted by the World Agroforestry Centre in Kenya, most sub-Saharan African countries are currently using at most five percent of their rainwater potential. By recognising and incorporating the greenwater, the water ignored in hydrological planning, it may be possible to improve the food insecurity situation while also protecting the environment.

Kenyan farmers have traditonally over relied on rain fed agriculture without considering how to deal with dry spells. This has affected yields with grain yields being less than a tonne in a hectate. While most farmers blame this on lack of physical water, experts point to the economics of water. “We usually have floods that drown our people, so much water. So we cant say it is lack of water. It is pretty much lack of investments to capture and also boost water storage,”said Dr. Sila.

A recent study by The International Water Management Institute (IWMI) identified small scale water harvesting as the key to a near tripling of sub-Saharan Africa's yields.