Sand dams freeing dryland communities from water crisis
Anna Mwandikwa draws water from a pond behind a sand dam at the section of River Mutwawewa which passes through Ilianthi Village in Kitui County on October 4, 2023.
What you need to know:
- Kitui Governor Julius Malombe says the devolved unit will construct 2,400 sand dams in the seasonal rivers cutting across the semi-arid county.
- At least 114 new sand dams have been completed.
Armed with a calabash, Mary Mwendwa scoops sand in search of water on the dry bed of River Mutwawewa in Kitui County. Her face lights up as she draws water from the pond she has created some 30 centimetres below the surface of the sand bed.
The mother of three fills her six jerricans, straps them on her two donkeys and starts her journey from the oasis sprawled on the foot of the enchanting Katui Hill. The communal watering point is hinged on two sand dams constructed across the rocky riverbed.
“This is clean water,” says Ms Mwendwa as she sips from her calabash. Ten years ago, it would take Ms Mwendwa at least six hours to draw the six jerricans of water.
“I’m happy because the time I take to draw water has reduced to one hour,” she adds. Sand dams provide a sustainable solution for water-scarce Kitui County amid climate change. A second sand dam constructed by the Kitui County government has boosted the availability of the scarce commodity.
Known locally as mung’eeto, a sand dam is a rainwater harvesting technology that entails the construction of a weir across a seasonal river.
A weir is a small barrier built across a stream or river to control and raise the water level slightly on the upstream side, essentially a small-scale dam
Water from the accumulated sand flows into underground tanks known as sumbs, which are set right beneath sand dams from where the commodity is pumped to the communities.
Cows at a watering point formed behind a sand dam at the section of River Mutwawewa, which passes through Llianthi village in Kitui County on October 4, 2023.
The rainwater harvesting technology has significantly reduced water conflicts at the source. Kitui County government has adopted this model to address perennial water shortages and food insecurity, and to restore rivers damaged by sand mining in support of the water for climate resilience and environment.
According to the UN Environment programme (Unep), the world is alarmingly off track in achieving the Sustainable Development Goals (SDG) 6 by 2030. SDG 6 aims to ensure the availability and sustainable management of water and sanitation for all.
Kitui Governor Julius Malombe says the devolved unit will construct 2,400 sand dams in the seasonal rivers cutting across the semi-arid county. At least 114 new sand dams have been completed.
“We shall construct 40 sand dams in each of the 60 wards across Kitui County by 2027. This year we are constructing 120,” said Dr Malombe. The sand dams have spurred agribusiness in Kabati, Katutu and Kithyoko townships.
“I earn Sh20, 000 a week selling vegetables,” says Alice Wayua, a 27-year-old farmer who grows assorted vegetables near a sand dam on the section of River Kithyoko.
Sand dams also benefit the local ecology as they provide a sustainable water source and conserve ecosystems by raising the water table around them.
Natural vegetation and biodiversity dependent on aquatic ecosystems near the sand dams also benefit.
“We have turned to sand dams to address water shortage and food insecurity by expanding the current 3,085 hectares of land under irrigation,” says Water and Irrigation Executive Peter Nkunda.
The devolved unit also trains farmers on good agricultural practices like drip irrigation to minimise water wastage.
This programme is a collaboration with South Eastern Kenya University and will cost the county government Sh2.4 billion. Experts advise that sand dams should be installed in moderation.
“Any abstraction and removal of sediments from a dry river bed deny the downstream river sediments which help in bank and bed stabilisation and percolation of water,” explains Ms Halinishi Yusuf, an expert on sand conservation.
“A sand dam should be located in a section of the river with an impervious bedrock and established river banks so that trapped water does not drain.”
Sandy riverbeds are the main source of water for Kitui residents but unregulated sand mining remains a threat to the survival of the rivers. However, the county government is in the final stages of enacting a law to regulate sand mining and trade.
“We must safeguard the rivers and address the demand for sand,” says Bretta Mwangangi, the chief officer in charge of irrigation. She says the county banks on sand dams to grow sand resources and reduce the pressure on river beds.
