Flood Traps: How Poor Engineering Is Worsening Flood Disaster in Adamawa

The rains had barely started when the water began rising inside Hajiya Falmata’s small provisions shop along one of the main streets in Jimeta, Yola North Local Government Area. By mid-morning, her stock was floating. Sachet water, seasonings, biscuits, everything she had carefully stocked during the dry season. By afternoon, her doorway had turned into a stream.

She stood outside and watched. Not in shock. Not in tears. Just watching, the way a person watches something they have seen before and already know they will see again.

“This is every year,” she said, pointing at the road in front of her shop. It was a stretch of tarmac with no gutters on either side. Its surface was slightly elevated, just enough to redirect every drop of rainfall straight into the homes and businesses lined up on both sides. “The road is higher than our floor. When it rains, the water has nowhere to go but inside.”

Hajiya Falmata’s experience is not a strange one. Across Adamawa State, from the flood-prone banks of Numan and Lamurde to the congested neighbourhoods of Yola South and Demsa, communities are being swallowed not just by rain, but by roads that trap water, culverts that have never been properly built or have long collapsed, drains that were never constructed in the first place, and buildings sitting on land that water has always used as its natural path. The rain is only revealing what poor engineering created long before the first drop fell.

In September 2022, floodwaters submerged 153 communities across 12 Local Government Areas in Adamawa State, displacing 131,638 people, killing 25, and injuring 58 others. The floods affected approximately 260,000 people across the state and caused extensive damage to roads, bridges, schools, and health facilities. In 2023, the story repeated itself with even greater ferocity. Between May and October of that year alone, over 70 people died, more than 490 were injured, and 57,000 people were forced to leave their homes, according to the joint multisectoral Rapid Needs Assessment cited by the United Nations Office for the Coordination of Humanitarian Affairs. More than 19,000 hectares of farmland were destroyed. The affected Local Government Areas included Lamurde, Yola South, Mayo-Belwa, Numan, Yola North, Fufore, Demsa, and Song — names that have become permanent fixtures in Nigeria’s humanitarian situation reports.

Year after year. The same communities. The same roads. The same flooded schools and washed-away markets.

But beyond the rainfall, beyond the seasonal water releases from Cameroon’s Lagdo Dam and the swelling of the Benue tributaries, engineers, researchers, and residents are pointing clearly at a deeper and more avoidable problem. Flooding in Adamawa, they say, is no longer purely a natural disaster. It is increasingly a man-made crisis, engineered into existence by poor construction decisions, weak drainage infrastructure, and a culture of building without consequence.

When Roads Become the Enemy

To understand how roads contribute to flooding in Adamawa, you need to understand what a properly engineered road is supposed to do with water. A well-designed road has a gentle camber, a slight slope across its width, that guides rainwater away from its surface and toward a drainage channel on the side. That channel connects to a larger stormwater network. Culverts, the concrete or metal pipes built beneath road crossings, carry that water safely under the road and onward. The whole system is designed with one purpose in mind: to move water away from people as quickly and safely as possible.

In Adamawa’s flood-prone communities, almost none of these elements function as they should. Roads across Yola South, Lamurde, Numan, and Fufore are built with raised edges and no outflow points. When rain falls, the road surface becomes a shallow lake. Water rises on both sides and, following gravity, enters whatever low point is nearest, which is usually a home, a shop, or a farm.

Engineering standards for road drainage design are clear and well-documented. Road drainage design guidelines affirm that adequate drainage is of paramount importance in road design and cannot be overemphasised, and that the presence of excess water or moisture within a roadway will adversely affect the engineering properties of the materials with which it was constructed, leading to cut or fill failures, road surface erosion, and weakened subgrades followed by mass failure. In plain terms, a road built without drainage does not just flood communities. It also destroys itself in the process, creating the potholes and collapsed stretches that communities also endure every rainy season.

Research on soil-structure interaction and road infrastructure in Nigeria’s flood-prone areas published in peer-reviewed engineering journals has established that inadequate stormwater management in road construction is one of the leading causes of both road failure and community flooding in Nigerian contexts, recommending that culverts and concrete-lined drains be treated as critical hydraulic structures in every road project. This is not a new finding. It has simply not been applied consistently in Adamawa.

A 2025 federal government road rehabilitation exercise in Bauchi State illustrated what compliance looks like in practice. The Federal Controller of Works explained during an inspection that the culverts and concrete-lined drains constructed along rehabilitated roads were critical hydraulic structures designed to ensure roads, farmlands, and communities remain safe and accessible. That standard exists on paper for road projects across Nigeria. The question is why it has not been enforced on the roads that matter most to the communities that flood every year in Adamawa.

The Culvert Problem Nobody Talks About

Of all the engineering failures that contribute to flooding in Adamawa, blocked, undersized, and missing culverts may be the most widespread and the least discussed.

A culvert is a straightforward structure. It is a pipe or channel, usually made of reinforced concrete, that passes beneath a road to allow water to cross without interrupting traffic or accumulating on one side. Every road that crosses a drainage path, a seasonal stream, or a natural water channel is supposed to have a properly sized culvert beneath it. The size of the culvert must be calculated based on the volume of water the surrounding catchment area can generate during peak rainfall. Get the size wrong and the culvert becomes a bottleneck. Leave it out entirely and the road becomes a dam.

In Adamawa, both failures are common. Communities across the state have roads that were constructed over natural drainage paths with no culverts at all, leaving water nowhere to go when the rainy season arrives except backward into nearby homes. In areas where culverts were originally installed, many have collapsed under vehicle load because they were not designed to carry the weight of modern trucks and heavy vehicles. Others have silted up over years of neglect, their openings choked with mud, plastic waste, and debris until they can no longer pass any meaningful volume of water.

A study published in an engineering journal examining drainage infrastructure across Nigerian towns found that existing culverts and drainage structures were hydraulically insufficient, meaning they were built too small for the actual volume of water they needed to carry. The study found that the current drainage structures showed significant deficiency in carrying capacity when compared with design requirements, and that this inadequacy was directly responsible for road failure and localised flooding in the areas studied.

This pattern is replicated throughout Adamawa. A community that relies on a single undersized culvert to drain an entire neighbourhood during peak rainfall is a community that will flood. Not because of exceptional rainfall, but because the structure that was supposed to move water simply cannot handle the load it was always going to face.

Maintenance compounds the problem further. Even culverts that were originally built to adequate specifications become ineffective when they are not regularly cleared. Nigeria’s rapid growth in urban population has consistently outpaced government capacity to maintain basic infrastructure. Research assessing Nigeria’s drainage systems found that rapid urban growth had outpaced government capacity to provide adequate drainage infrastructure, and that non-compliance with planning ordinances had made this worse over time. In Adamawa’s secondary towns and rural LGAs, the resources and institutional capacity for culvert inspection and maintenance are minimal.

Drains That Were Never There

A drainage channel is one of the most basic pieces of infrastructure a community needs. It is simply a lined or unlined trench along the side of a road or within a neighbourhood that collects surface water and moves it toward a safe outlet. Without it, every paved surface in a community becomes a runoff contributor that sends water directly into the lowest available point.

In large parts of Adamawa, residential streets have no drainage channels at all. Roads are tarred or graded and handed over to communities without any accompanying drainage infrastructure. Houses are built, compounds are cemented, streets are packed with traders and motorcycles, and nobody asks where the water is supposed to go when it rains.

A quantitative assessment of open drainage and stormwater runoff capacity in Nigeria published in a scientific journal found that Nigeria’s drainage channel deficit stands at approximately 61.78 percent. This means the country has built fewer than four in every ten drainage channels that its current urban population requires. Of the channels that do exist, only about 30 percent are being adequately maintained. In practical terms, this means that the majority of Nigerians in urban areas live without a functional drainage system. In Adamawa, where investment in secondary town infrastructure has historically been limited, the deficit is widely acknowledged to be more severe than the national average.

Where drainage channels have been constructed, design failures often neutralise their effectiveness. Shallow channels that fill with water after even moderate rainfall do not provide meaningful drainage. Channels that are not connected to any wider drainage network simply collect water in one place before it overflows into the surrounding area. Channels built without adequate gradient, the slope that makes water flow, allow water to stagnate, become breeding grounds for mosquitoes, and eventually back up into the very roads and homes they were meant to protect.

The problem of solid waste makes everything worse. Residents who have no waste collection infrastructure have few alternatives but to dispose of refuse in the nearest available space, and in many communities that space is the drainage channel. Sachet water pouches, plastic bags, food waste, and debris accumulate in channels across Adamawa’s towns until those channels are functionally blocked. A blocked drainage channel is no longer a drainage channel. It is a container waiting to overflow.

Houses Built Where Water Was Always Going to Go

One of the most visible contributors to flooding in Adamawa is a problem that begins long before any rain arrives. It begins when a building is approved, or more often not properly approved at all, on land that forms part of a natural drainage corridor.

Every landscape has natural pathways through which water moves after rainfall. These are determined by the topography of the land, the direction of slope, and the location of seasonal streams and wetlands. When a building is constructed across one of these pathways, it does not eliminate the pathway. It simply forces the water to find another route, usually through the nearest compound or along the nearest street.

In Adamawa, residential expansion has placed thousands of structures directly on floodplains, seasonal drainage paths, and the banks of rivers and streams. The communities along the Benue River corridor in Numan and Lamurde LGAs have expanded steadily onto land that the river seasonally claims. Yola South’s dense residential quarters have grown over natural drainage channels that once carried water safely through the area. In smaller towns across Fufore, Mayo-Belwa, and Demsa, houses have been built inside shallow valleys and low-lying ground without any assessment of drainage impact.

A 2025 analysis published in Frontiers in Sustainable Resource Management examining flood resilience and urban development in Nigeria found that uncontrolled urbanisation, including construction on flood-prone land and along waterways, is the most significant socio-economic factor in escalating flood risk across Nigerian communities. The same research confirmed that the expansion of impermeable surfaces, the concrete compounds, the tiled yards, the paved paths within residential areas, reduces the natural absorption capacity of the soil and significantly increases the volume of surface water that must be managed when rain falls.

Nigeria’s National Inland Waterways Authority Act establishes a 100-metre setback from the edge of both banks of waterways, within which construction is prohibited. This law exists. It is simply not enforced in most of Adamawa’s expanding communities. Town planning officials lack the staffing to monitor construction across hundreds of communities spread across a large and partly remote state. Contractors who know this proceed without permits or with permits obtained through informal channels that overlook location restrictions entirely.

The result is a built environment that has progressively reduced the space available for water to go, concentrating flood volume into narrower and narrower corridors until those corridors overflow into homes and streets.

Streets Without Water Outlets: A Crisis Hiding in Plain Sight

Beyond individual houses and the roads that connect them, there is a broader pattern that affects entire residential streets in Adamawa’s towns and that is rarely discussed in formal flood response conversations. It is the problem of streets that were laid out and built up without any provision for where water would exit the neighbourhood.

A well-planned residential street is part of a drainage network. Rainwater that falls on rooftops and compounds flows into gutters along the side of the street. Those gutters carry water to a main drainage channel or a culvert that connects the neighbourhood to a larger stormwater system. The design is interconnected by intention. Every component knows where the water is going next.

In many of Adamawa’s residential areas, that interconnection does not exist. Streets were developed organically as communities grew, without a master drainage plan. Houses were built close together, often with their compound walls meeting at the street edge, leaving no space for a drainage channel. In some neighbourhoods, residents have built small individual gutters in front of their homes that direct water into the street, where it accumulates because there is nowhere downstream for it to go. The street then floods. Water backs up into compounds. In areas where the street is lower than the surrounding ground, an entire neighbourhood can sit in standing water for hours or days after a heavy rainstorm.

This is not a problem caused by exceptional rainfall. It is a problem caused by the complete absence of drainage planning at the neighbourhood level. Research on urban flooding in Nigeria consistently identifies the failure to integrate drainage design into residential street planning as a primary contributor to localised flooding, and notes that the non-compliance with planning ordinances that would require this integration has persisted across Nigeria’s urban areas for decades.

In Adamawa’s secondary towns including Numan, Ganye, Mubi, and Gombi, this gap between what planning laws require and what is actually built on the ground is wide enough to flood entire residential quarters during a single rainstorm. Residents have adapted by raising their thresholds, elevating their doorways with concrete steps, placing sandbags before their entrances, but these are household-level responses to an infrastructure-level failure.

Climate Change Is Making a Bad Situation Worse

It would be incomplete to discuss flooding in Adamawa without acknowledging what climate change is doing to the baseline conditions that all of this infrastructure must now handle.

Nigeria’s climate change profile, documented by the World Bank’s Climate Change Knowledge Portal, confirms that the country is experiencing increasing rainfall variability, with more frequent and intense precipitation events, particularly in the north. Adamawa sits at the convergence of the West African monsoon system and the Sahel, making it climatically sensitive to shifts in both systems. Research published in Scientific Reports analysing rainfall patterns in northern Nigeria from 1979 to 2022 found that rainfall anomalies in the northern part of Nigeria are coupled with variability in sea surface temperatures across the global oceans, meaning that global climate patterns are directly shaping how much rain falls on Adamawa and when.

Research on rainfall patterns in Adamawa found that the length of rainy days has significantly decreased in the northeast, while the intensity of rainfall when it does occur has increased. This means the same volume of water that once arrived gradually across many rainy days is now arriving in shorter, more intense bursts. Infrastructure designed for gradual rainfall cannot manage sudden high-volume downpours. Culverts sized for older rainfall patterns overflow during the new normal. Drainage channels that could handle moderate flow rates are overwhelmed. The consequence is more flooding, more rapidly, even when the total seasonal rainfall is not dramatically different from historical averages.

Climate change in Nigeria has caused increasing temperatures and rainfall variability, resulting in floods, and more frequent extreme weather conditions, with the country being highly vulnerable to and not well prepared to deal with the effects of climate change.

This climate reality means that the infrastructure failures described throughout this report are not just a problem for today’s rainfall. They are a compounding vulnerability. Every undersized culvert, every neighbourhood without drainage, every house built on a floodplain, every road without gutters, becomes more dangerous with each passing rainy season as the intensity of rainfall events increases. Building to yesterday’s engineering standards in today’s climate is not neutral. It is a decision to flood.

The Lagdo Dam Factor and the Dam That Was Never Built

Adamawa’s flood vulnerability cannot be discussed without addressing the role of Cameroon’s Lagdo Dam, which sits on the Benue River upstream of the Nigerian border and whose seasonal water releases have repeatedly devastated communities downstream in Adamawa and beyond.

The release of water from Lagdo Dam has long been a cause for concern in Nigeria, as it results in the swelling of the Benue River, which traverses multiple Nigerian states, including Adamawa and Taraba in the northeast region. When Cameroon releases water from the dam during peak rainy season, it adds a sudden and massive volume of water to a river system that is already running high from local rainfall. Communities along the Benue corridor in Numan, Lamurde, and Fufore LGAs have no meaningful protection against this surge.

The existing agreement between Nigeria and Cameroon does not explicitly provide for communication of the timing of seasonal releases from the Lagdo Dam, meaning Nigerian authorities often rely on inter-personal professional relationships between hydrological services of both countries rather than a formal notification system.

The engineering solution to this problem was identified decades ago. When the Lagdo Dam was constructed in 1982, Nigeria committed to building a buffer dam at Dasin Hausa in Fufore LGA, Adamawa State, that would retain and regulate water flowing from the Lagdo Dam before it reached populated areas downstream. That dam has never been built. Experts argue that without the completion of the Dasin Hausa Dam, responses to Lagdo Dam releases will only serve as temporary fixes, and while officials from the Federal Ministry of Water Resources and Sanitation have repeatedly affirmed commitment to completing the dam, logistical, financial, and political hurdles persist.

The completion of the Dasin Hausa Dam in Adamawa State is identified by researchers as a priority infrastructure intervention for addressing Nigeria’s flooding crisis, alongside appropriate stormwater management regimes, riverbank protection, and ecosystem-based adaptation measures including reforestation in river catchments and planting native vegetation on claimed floodplains.

Every year that the Dasin Hausa Dam remains unbuilt is a year that Adamawa’s riverside communities absorb a flood surge that engineering could have managed. The dam has been on the agenda since 1982. Communities have been flooded every year since.

The Human and Economic Cost

The people who live through Adamawa’s floods are not statistics, but the statistics help to understand the true scale of what poor engineering is costing.

In 2022, the floods affected approximately 260,000 people across the state. 131,638 were displaced, many into overcrowded IDP camps or the already stretched homes of relatives. 153 communities across 12 LGAs were submerged. Twenty-five people died. Fifty-eight were injured. Roads, bridges, schools, and health facilities were damaged or destroyed across the state.

In 2023, more than 70 people died and over 490 were injured in Adamawa alone. 57,000 people were displaced. More than 19,000 hectares of farmland were destroyed at a time when Adamawa’s farmers were already managing food insecurity driven partly by conflict in surrounding areas. OCHA confirmed outbreaks of cholera, diarrhoea, malaria, and dengue fever triggered by floodwater contamination of community water sources. In Yola South’s Wauro Jabbe community alone, 38 confirmed cholera cases were recorded and referred for treatment following the floods.

At the national level, the World Bank’s Global Rapid Damage Estimation assessment concluded that the 2022 floods caused direct economic damages estimated at between $3.79 billion and $9.12 billion, with the median figure at $6.68 billion. Infrastructure damage, including to roads, bridges, and irrigation systems, accounted for approximately $1.23 billion of that figure.

The NBS and UNDP Nigeria Flood Impact, Recovery and Mitigation Assessment Report for 2022 to 2023 found that 64 percent of affected households had not meaningfully recovered from the 2022 floods before the 2023 rains arrived. In rural areas, where most of Adamawa’s flood-affected population lives, the impact rate was 74 percent. These are communities perpetually in recovery, perpetually behind, perpetually preparing for the next round of a crisis that proper engineering could substantially reduce.

For farmers, flooding destroys not just the current harvest but the next planting cycle too. Waterlogged soil takes weeks to drain and dry enough to be worked again. Seeds stored in flooded homes are lost. Livestock drown or are lost in floodwaters. For traders whose entire inventory was in a shop that filled with water overnight, there is no insurance payout, no government compensation, no path back that doesn’t involve starting over from nothing.

“We lost the road to Numan for weeks,” one farmer in Lamurde LGA described. “No lorry could pass. The onions we planted, we couldn’t sell them. They rotted on the farm.”

What Government Has and Has Not Done

Nigeria has a formal institutional framework for flood management. NEMA, AdSEMA, the Adamawa State Ministries of Works and Environment, the Urban Planning Authority, and NIHSA all carry mandates directly relevant to flood preparedness and drainage infrastructure. Flood alert systems exist. NIHSA monitors river levels and communicates threats to state governments. Building codes are in force. Setback regulations from waterways are established in law.

The gap between what these institutions are mandated to do and what consistently happens on the ground is, however, very wide.

OCHA’s November 2023 Situation Report revealed that the flood preparedness and response plan for the BAY States, Borno, Adamawa, and Yobe, was critically underfunded. The Camp Coordination and Camp Management sector was only 6.4 percent funded. The Shelter and Non-Food Items sector reached just 51.2 percent funding. These are not marginal shortfalls. They represent a humanitarian response infrastructure that cannot adequately serve the people it exists to protect.

More fundamentally, the system spends far more energy and resource on responding to floods after they occur than on preventing them through engineering standards and planning enforcement. Contractor accountability remains a specific and documented gap. Roads and drainage projects are awarded, built to minimum or below-minimum standards, handed over without independent technical inspection, and then left to communities that have no recourse when the drainage channels are missing or the culverts collapse in the first heavy rain.

What Needs to Change, Concretely

The solutions to the engineering failures described in this report are not complicated in concept, though they require sustained political will and investment to implement.

Every road construction contract in Adamawa must include mandatory drainage design as a non-negotiable element. Camber, roadside channels, culverts sized for actual peak rainfall volumes, and connection to a wider stormwater network must be specified in design documents and verified at implementation by independent engineers, not just signed off by the contractor. Roads delivered without drainage should not be accepted or paid for.

Existing roads in flood-prone LGAs need drainage retrofitting as an emergency priority. This means excavating roadside channels, installing or replacing culverts, and connecting those channels to viable outflows. It is less expensive than replacing flooded infrastructure and incomparably cheaper than repeated post-flood humanitarian response.

Nigeria’s drainage deficit of over 61 percent cannot be reversed without dedicated budget lines at state level. Adamawa State must allocate specific and ring-fenced funding for drainage construction and maintenance in the LGAs most consistently affected by flooding. Drain desilting must become a routine and funded activity, not something that happens ad hoc after a flood has already occurred.

Floodplain encroachment must be addressed through genuine enforcement. The 100-metre waterway setback requirement established in Nigerian law needs to be applied consistently. Structures already built within protected zones need to be mapped, and a structured programme of voluntary or compelled relocation, with viable alternatives provided for the poorest households, needs to begin. Approving new structures on floodplains while the same floodplains flood every year is not a governance position. It is a dereliction of duty to the communities affected.

Neighbourhood-level drainage planning must become a requirement for all new residential development approvals. No street layout should be approved without a demonstrated connection to a wider drainage network. The days of tarring roads and handing them over without asking where the water goes must end.

The Dasin Hausa Dam must be built. Four decades of deferred commitment have cost Adamawa’s riverside communities immeasurably. This is not a new recommendation. It is a promise made in 1982 that has simply never been kept.

A Structural Failure in Rainwater

Every year, as the rains arrive in Adamawa, the same question rises with the floodwater: is this a natural disaster or a man-made one?

The honest answer is that it is both, and the man-made portion is growing.

Climate change is real. The Lagdo Dam releases are real. The seasonal flooding of the Benue and its tributaries is a geographical fact that Adamawa cannot change by itself. But the community in Lamurde whose only road has no drainage did not choose that road. The family in Yola South whose compound sits below the elevated tarmac outside their gate did not design that road. The farmer in Fufore whose crops disappear under water every September is not the author of her own crisis. The trader in Numan who stacks sandbags outside her shop before every rainy season is not solving a natural problem. She is coping with an engineering one.

The data is not ambiguous. In 2022, Adamawa’s floods displaced over 131,000 people and submerged 153 communities. In 2023, over 70 people died, 57,000 were uprooted, and 19,000 hectares of farmland were destroyed. The World Bank estimated national flood damages at a median of $6.68 billion. The NBS and UNDP found that 64 percent of affected households had not recovered from one season before the next arrived. These are not the numbers of a natural disaster that has been adequately met. These are the numbers of a structural failure that repeats with the predictability of the rainy season because the structures that caused it have never been fixed.

Until roads in Adamawa are designed to move water away from homes rather than into them, until culverts are built to carry the volume of water their catchments actually produce, until drainage channels are treated as essential infrastructure rather than optional additions, until residential streets are planned with an exit for every drop of rain, until buildings stop being approved on land that water has always claimed, and until the Dasin Hausa Dam moves from promise to concrete, flooding in Adamawa will remain less of an act of nature and more of a consequence of choices that were made, and that can be unmade.

The rains will come. They always do. The question is whether the roads, the drains, the culverts, and the planning decisions will finally be ready for them.