Whenever it rains in Nairobi, as it has over the past few days and weeks, the city’s worst face froths to the surface.

When Nairobi receives a few inches of rainfall, its drainage system, woefully inadequate even in non-emergency situations, gets overwhelmed and leaves city residents in a flood of fury.

As rains pummel the city, evidence of Nairobi’s creaky drainage system is everywhere: a trail of death, filth, crumbling walls, crumbling houses, fallen trees, impassable roads, potholes turned into craters, flooded roundabouts, deluged cars, stranded commuters, stalled trucks and intractable traffic jams.

The ramshackle drainage system converts a handful of millimetres of rain into a cesspool in which sewage swishes through classrooms and homes that have degenerated into a shambles, leaving swathes of the city engulfed in foul smell.

The roads bear the brunt of Nairobi’s creaking drainage system whenever the city, as a bulge of second-hand cars grinds to a halt in muddy waters and others slam into each other in pile-ups, ending dozens of lives and changing other lives forever.

At the sight of rains, matatu fares hit the roof, for in Nairobi, profiteers are always lurking at every corner waiting to coin it from the miseries of the long-suffering city residents.

From the shacks in the city’s informal settlements to the genteel mansions of up-scale neighbourhoods, the rains routinely knock out the city’s unreliable power supply, leaving residents groping in the dark while providing cover for hordes of criminals on the prowl.

Nairobi’s pitiful drainage system is a case study in the dysfunction at City Hall and a running joke on social media, with neighbourhoods such as South C being referred to as South Sea, as its residents muddle through muddy waters.

A rained-soaked Nairobi is not only a toughening boot camp, but also provides its residents with ample opportunities to get sick, from the raw sewage gushing across the city’s estates to the implacable cholera outbreak currently on the march in parts of the city.

The city’s creaky drainage system is a stunningly obvious fact that has been given short shrift by the authorities for decades. Many experts attribute this problem to the lack of drainage infrastructure during road construction and maintenance, developments along riparian reserves, and newly built up areas that block natural water flows.

Others contend that the drainage system installed in the 1920s has barely been upgraded to match both the planned and unplanned developments wrought on the city over the years.

Whatever the case, the unbelievable degradation of the city’s drainage system is not only an infrastructural catastrophe crying for attention, but also a humanitarian crisis. Drainage in the city’s slums is worse due to haphazardly developed structures that are grubby beyond imagination and constructed without consideration of natural water flows, riparian reserves and wetland management.

According to many estimates, slums host 60 per cent of Nairobi residents, who are crammed into less than 5 per cent of the city’s residential area and just over 1 per cent of all land in the city.

Life is already precarious in the slums, where hard-scrabble lives hang by a thread. As many wobbly shacks are flattened, other rickety structures groan and shake violently whenever rains lash these underprivileged areas.

In these impoverished settlements where fetid water flows freely and dozens share one toilet, families cling to each other and utter prayers begging for mercy as rains pound their decrepit structures hour after unending hour.

Besides eroding the dignity of residents, the poor drainage system is the cause of many health and environmental problems in the slums.

Nairobi may well be at the peak of a stupendous economic boom, as evidenced by the skyscrapers and the so-called gated communities sprouting every day. It may also be the most intelligent city in Africa, according to Intelligence Community Forum, an international think tank.

But its creaky drainage system sticks out like a sore thumb. Painfully aware of the gulf between election promises of shiny streets and the reality of deluged and potholed highways and byways, many Nairobians have quickly learned the calculus of surviving the poor drainage system.

The statement for it, which has become a national mantra, is; “accept and move on.” But those with shreds of hope are haunted by a vexing question: Who will give the decrepit drainage infrastructure a new lease of life?

The politically downwardly mobile Governor Evans Kidero seems feckless.

His recent orders to Kenya Urban Roads Authority and Kenya Highways Authority to fix the dreadful drainage system that causes flooding along most of the city’s roads are yet to yield any concrete action.

Members of Nairobi’s Assembly, the newly prosperous representatives from whom we expect solutions to the city’s problems, seem busy cutting deals and amassing wealth to bankroll their future election campaigns.

To these wheeler-dealers run amok, the city’s poor drainage system seems to be just another nuisance for which they have no time in their breakneck race to join the millionaires’ list.

Nairobians are used to hardships – from hideously corrupt officials to Al-Shabaab terror attacks, they stoically weather them all. Still, city residents shudder any time low, grey clouds stretch across the sky in a thin veneer of menace. For rain, in its own oblique way, reminds Nairobians of the city’s rotten drainage infrastructure.

A proper, functional drainage system should be non-negotiable. No effort should be spared in giving Nairobi a drainage system worthy of its status.