What should be done to end perennial flooding in Budalangi?

Mabinju residents flee to higher grounds in Rwambwa, Budalangi, following heavy rains on April 28, 2024. [Benjamin Sakwa, Standard]

The Budalangi flood plain in Busia County, where the Nzoia River flows into Lake Victoria, is well known for catastrophic flooding.

Repeatedly over the past century, severe and prolonged floods in the area have displaced thousands of people from their homes.

This year, Budalangi has been pressured on two fronts. Not only have large volumes of water been swept down the Nzoia River from its headwaters in the Cherangani Hills. Heavy rainfall right across East Africa has caused the water level in Lake Victoria to rise a record 1.3 metres above its normal level.

On the one hand, Budalangi has had to cope with exceptionally large volumes of river water rushing downstream from the highlands and spilling out over its croplands.

On the other hand, this fertile low-lying plain has also been pressured by rising water levels in Lake Victoria. Its shoreline has pushed inland, flooding several communities in the process. The rising level of the lake has forced water from the Nzoia River to flow back into the Budalangi floodplain more than usual.

Our people and our government need to recognise this trend and do more to mitigate its consequences.

So, what exactly needs to be done?

Firstly, the winding course of the lower reaches of the Nzoia River needs to be straightened so that its water empties faster and without impediments into Lake Victoria. Nzoia River currently meanders slowly for 40km in a winding course across the Budalangi flood plain before it reaches the lake. This allows up to five million cubic metres of water to be retained in the river as it flows slowly through Budalangi. That is more water than you will find in the reservoir behind Masinga hydro-electric dam on the Tana River!

Digging canals across Budalangi would allow the river to follow a straighter and more direct course of just 18km from the point where it enters the flood plain to where it reaches the lake. This would enable high volumes of water in the rainy season to rush straight through Budalangi like an express train, instead of slowing down, building up and spreading out over the adjacent farmland.

Secondly, we need to dredge the main channel of Nzoia River where it empties into Lake Victoria. Special boats equipped with chains of buckets that dig up mud from the riverbed would cut a deep channel through the layers of silt that have accumulated on the riverbed. A deeper channel would allow the river to flow into the lake faster and more easily. It would help to prevent the river from backing up into Budalangi to the point where it overflows the dykes on either side of its channel and floods adjacent farmland.

Those dykes – high and broad earth walls along either side of the riverbed – are supposed to keep the river flowing in its proper course, even when the water level rises. The dykes were built 50 years ago, shortly after independence, and require constant repair and maintenance. Floods only occur when these defences are breached. Water then pours through gaps in the dykes into neighbouring fields.

Thirdly, mud dredged up from the bed of the Nzoia River would be used to strengthen the dykes along its bank and create up to 17,000 hectares of reclaimed land for agriculture. The rich soils of this reclaimed land could potentially produce maize yields of eight tonnes per acre, giving an annual harvest worth three to four billion shillings. If the reclaimed land were turned into fishponds, the economic yield from farmed tilapia could be even higher – up to seven billion shillings.

The socio-economic turn-around triggered by these interventions can make donors develop the urge to support the government.

It is also essential to keep in mind that any downstream interventions without putting similar pressure on upstream interventions can be counterproductive. The continued land rehabilitation upstream will be essential to be considered for comprehensive management of Budalang’i flooding.

Effective catchment-based integrated practices that enhance infiltration, reduce moisture stress, improve soil fertility, and reduce sedimentation need to be implemented upstream of the river catchment.

The government has the potential to turn Kenya’s biggest flood hotspot into a dynamo of economic activity that will enrich its inhabitants instead of ruining them through periodic floods.

-Mr Bahati is County Director Meteorological Services. Mr Obuyu is an engineer based in Budalangi