How to protect your house from floods

By Christopher Bendana

Kagoda got a shock of his life when water woke him during  the November rains. When it rains heavy his house is submerged. Kagoda’s bungalow valued at over sh350m is the talk of many of his friends, especially those he worked with aboard.

This is, however, only true during the dry season. His home in the Nateete, Rubaga Division, was built in a wetland. While he worked in the UK, he boutght the land through his brother and built in a flat valley, which is prone to logging.

Nateete like most parts of Kampala, including Mulago Nsooba, Bwaise, Ndeeba, Luzira, and Bugolobi are in the water catchment of Lake Victoria, hence prone to flooding as the water moves its way to the lake. Additionally, much of the flat lands of Uganda such as Butaleja, Teso sub-region and northern Uganda have experienced flooding.

Although environmentalist say the major cause of flooding is the destruction of the wetlands, countries like the Netherlands that are below sea level and reclaimed much of its land from the sea have not been submerged because they built dykes to stop the waters. Dr. Max Kigobe, a lecturer in the department of civil and environment engineering at Makerere University, says flooding depends on the amount of rain water one country receives.

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Water sweeps through a house

Although some areas might be in lowlands, they may receive less rainfall hence the flooding will be minimal. He adds that where the water is coming from also matters. There are areas that receive heavy rainfall, making all the land in their catchment  area susceptible to floods. “The catchment area where the house is built matters, the further downstream the bigger the catchment area hence the more vulnerability of flooding.”

This makes areas like Bugolobi, which are near Lake Victoria more vulnerable as they are the catchment area of much of Kampala He also mentions the nature of the soil structure as a factor on how long water will hold in a particular area. From those that allow easy movement of water to those that hold it. On protection against the water, he says that a buffer zone like reinforced walls can protect the house from flooding although he advises builders to use precast reinforced concrete if the house is to be sustained.

Apart from the buffer zone, he also mentions the use of hardcore stones when building the house foundation. He recommends the laying of drainage pipes in the foundation to help with the drainage of the water. He says a layer of clay and a polythene  bag can also be put above the hardcore to prevent water perforation on the floor and the walls of the house.

This prevents the peeling of plaster off the walls Anatoli Kamugisha, a property developer with extensive building experience, says the first step in protecting a house against flooding is to establish whether the flooding in the area is seasonal or temporary.

To prevent flooding in flat lands, he advises the partition of the plot in two parts. Part A for the house and part B for the pond where the water is to drain. If the plot has access to the drainage, he advises the developer to drain in the drainage system. “T he channel should be above two metres above the surface,” he points out.

Kamugisha says all this depends on the size of the catchment area. He also says eucalyptus or pine trees should be planted to hold the soil and reduce the amount of water in the soil. He further says that having a ground beams prevents the house from sinking. He warns of treating waste and water together. “The waste must not get contaminated with the water. It must be treated separately.”