By Padili James Mikomangwa, Daily News/NECJOGHA
Dar es Salaam, Tanzania – Available records show significant cases where rainfall has induced extreme consequences, constraining domestic and economic activities.
Evidently, such natural forces demolish our infrastructure beyond our own capacity to be functional. Tanzania receives an average of 1107mm of precipitation annually results in areas like Mwanza, Arusha and Bukoba receiving a lot of rain.
In that context, human lives, buildings, and infrastructure are prone to severe destruction every year, while established infrastructures fail to fathom rainwater devastating forces. According to the World Bank, in May of 2019, uninterrupted rainfall caused serious flooding in Dar es Salaam, where up to 1,215 households were displaced, roads and bridges destroyed and 1,560 homes wiped away.
This disaster extends the growing list of flood events having struck the city in recent years. In 2015, Mwanza region was affected greatly particularly in Mabatini, Kilimahewa, and Nyamanoro, buildings submerged and infrastructures, Morogoro, Rukwa and Sumbawanga regions were victims of flooding too.
The major culprit of such mayhem tend to be the crude infrastructure systems, which are less repaired and inefficient. Further information shows that Dar’s exposure to floods is wide-spread with at least 39 per cent of the population (over 2 million people), impacted either directly or indirectly by floods.
The April 2018 flood was recorded to have affected between 900,000 and 1.7 million people, and among affected households, 47% (18% of city population) reported health impacts.
Patently, Mwanza and Dar es Salaam regions undergo long rains shocks, especially when rainfall exceeds the city’s infrastructure capacity and resilience to withhold and channel running water. These ill-made roads, settlements and drainage layouts fail to wield running water forces breaking apart through house cracks, clogging streets, roads and settlements.
However, its not only Tanzania which experiences heavy rainfall in the world. New Zealand has been experiencing such extreme conditions since 2012 causing widespread destruction of infrastructure.
There is a possibility of a fruitful substitute, which is sustainable architecture utilized by Asian industrialized nations such as China and Japan. Sustainable architecture is a technology which intends to minimize environmental shocks such as earthquakes, hurricane and particularly heavy rains resulting in flooding by employing better use of energy, materials, development space and ecosystem at large.
This idea was conjured by an architect named A.Trivelli in 1998. It employs conscious approaches to conserve the natural environment and energy within built environment designs.
This technology primarily aspires the downplay of the serious consequences triggered by natural hazards and ascertaining present actions, so that they may not affect the future generation.
Mwanza, Mtwara, Rukwa and Dar es Salaam regions are not the only locations in the world that rainfall comes about, other geographical locations globally encounter such extreme weather conditions namely: UK, New Zealand and China.
Plainly, a new wave of architectural design is required, a design that assumes a sponge mechanism, a design that creates cities across Tanzania, to behave like sponges—rather operate as sponge cities.
Mwanza, Morogoro and Dar es Salaam particularly can be designed as a sponge city: this can be achieved by absorbing rain water, harvesting it and more importantly through establishing green spaces that naturally filter and retain water, green roofing to trap water, investing in porous designs on roads and pavements to absorb water and accommodate pedestrians and vehicles.
It is with no doubt that, the designs will certainly, assure more water for the cities, reduce flood risks, provide cleaner ground water and eliminate burdens on drainage systems which are eventually over run throughout the rainy seasons.
Restrained access to affordable land for housing has led to hilltops, valleys and river valleys being occupied despite being prone to array of natural and manmade disasters, Msimbazi Dar es Salaam, Unga Limited in Arusha, Mabatini and Kilimahewa in Mwanza are noted locations, succinctly impoverished individuals residing in these flood-prone areas are left with no choice but to face the consequences during long rains.
Potential stakeholders ought to embrace the concept that times have changed and incoherent infrastructure and housing plans assume no place in the future. Laying underground culverts to channel running water to storage facilities, would extremely avert heavy rainfall disasters, raising flood barriers, embankments is crucial, as well as building houses above flood level.
Copying Asia’s built environment technology and UK flood defence plans would suit Tanzania’s infrastructure needs. In 2015 the UK was victimized by flooding affecting thousands, due to its deliberate actions in averting natural hazards,costly and state of the art flood-resistant structures designs were institutionalized.
There are houses built on hills in California USA, similar to Mabatini in Mwanza, yet designs differ in supporting buildings’ capacity and resilience to fathom nature’s forces.
There are few buildings found at University of Dar es Salaam that affirm this, they have been built on sloping ground, unambiguously one of the lecture halls has a ship structure mimicking the topography of the location, such attempts should be embraced.
Sustainable architecture designs are paramount as they reduce significant amounts of money and time exhausted on rescuing people, renovating roads, bridges and settlements yearly.
Architects, geographers, environmentalists and engineer’s sustainable ideas are crucial, flood resilience concepts and heavy rainwater storage designs are essential in denigrating widespread materials and loss of lives.
It is essential to change the way we act, today and act for the future to safeguard the next generation’s survival.
Rains continue to pound Dar as KMD also warns of heavy rains in parts of Kenya Dar floods cost city $100m in damages last year