By Emeka Achebe
In Anambra State today, there are over 600 active erosion sites of varying dimensions. The state government has at various times cried out for a state of emergency to be declared on erosion in the state.
Erosion is the wearing away of soil particles resulting from stormwater runoff. The erosive impact of runoff on the soil is incremental and, if not prevented, leads to various forms of erosion. The best known and most destructive form of erosion in Anambra State is gully erosion. Gully erosion starts as a negligible cut in the soil called rill. Over time, it becomes larger when exposed to more flow, growing in length, breadth and depth, until a large valley is formed. Sometimes, the soil is weakened and collapses or sinks. This sinking is called a landslide or subsidence. When it happens in chains over a wide area, it is called an avalanche, in which large amounts of landscape cave in at the same time in huge landslides.
Gully erosion has caused much loss of life and property, consuming large swaths of the productive landmass in Anambra State. From Awka to Achina, Ekwulobia to Enugwu-ukwu. Practically all communities in the state are facing flood and erosion hazards. The cause of soil erosion is rainfall. It is no surprise then that almost all episodes of landslides occur during the rainy season. The rains are capable only because of the floods they generate. Floods are natural phenomena and are not destructive, if well managed. Flooding and erosion in Anambra State are destructive just because the right management tools for their control have not been implemented.
Through the interventionist effort of the Multi-scaled Nigeria Erosion and Watershed Management Project (NEWMAP), the Governor Willie Obiano administration has succeeded in providing succour to several communities in the state. NEWMAP was very effective in addressing the issue of erosion in the state since it made use of a holistic management watershed approach in its intervention.
Mrs Edith Oneka, from Umudunu Abagana, corroborated the efforts of NEWMAP in her story: “My house was just on the verge of falling into the ravine. It was just very close and I lost all hopes, until God intervened through NEWMAP, and, today we are saved.
“Before now, we used to trek long distances to meet with our relations because the gully divided our community, but the NEWMAP people came and reconnected us. They included everybody in this project, the young, old, men, women, youth, everybody. There was no gender bias. I am so happy, and I thank God for sending help through NEWMAP.”
The project successfully addressed not only the menace of gully erosion in the communities where it intervened but also its contributing factor. According to the project coordinator, Michael Ivenso, “Nigeria Erosion and Watershed Management Project is inarguably the most ambitious and most successful landscape restoration and climate adaption project in the history of Anambra State. An innovative and people-focused intervention led to the game-changing result across communities in the state. It is through adopting time-tested global best practices in environmental governance and social mobilization that we were able to reverse the devastating impacts of gully erosion and flood inundation.”
As the project commences its wind-down in the state, the question on the lips of Ndi Anambra has been, What next, after NEWMAP? What are these time-tested global best practices that stood NEWMAP out? The state response was two-fold, first, it established the Anambra State Erosion, Watershed and Climate Change Agency. This institution is specifically tasked with helping to perpetuate and encourage what NEWMAP has done and, secondly, it documented its approach in a manual titled “Erosion Control & Environmental Sustainability Manual: A Simple Guide to Community-based Erosion Control and Climate Change Action.”
According to Gov. Obiano, “My administration adopted best practices in the key areas of watershed management, climate adaptation, road infrastructure design, gully rapid action and slope stabilization. The support from the Federal Government and the World Bank provided the tools and innovative ideas in environment and social governance that produced the transformational results that we are all witness to. To ensure sustainability and the continued success of these efforts, I established the Anambra State Erosion Watershed and Climate Change Agency. This manual is designed to galvanize community-based actions to reverse the adverse impacts of gully erosion, flooding and other forms of land degradation, ensuring a safe and prosperous environment for Ndi Anambra.”
Gov. Obiano emphasised that community-based action was needed to reverse the adverse impacts of gully erosion, flooding and other forms of land degradations and ensure a safe and prosperous environment for Ndi-Anambra.
He said, “All communities and government agencies are, therefore, expected to take ownership by embracing and implementing best practices to guarantee a healthy and liveable environment for all and sundry”.
This effort by the state government is seen by pundits as a parting gift by the governor, as it is aimed at sustainably addressing environmental issues.
A cursory look at the manual shows that it did justice to many areas of environmental sustainability under different sub-headings, including facts on erosion, local best practices in flood and erosion control, community-based effort to erosion and flood control, actions against sand mining and deforestation, protecting forests and other natural assets, rainwater harvesting, humanitarian dimension, erosion control action-grassroots approach and going green. All in a simple, descriptive manner, with the necessary pictorial imagery for emphasis.
On the causes of erosion, the manual noted that prevalent episodes of erosion can be triggered by issues of indiscriminate building without patterns and plans, Rapid loss of forestland to deforestation and an increased runoff harvest due to rapid land-use development and infrastructures. It also noted the insufficient/efficient storm drainage infrastructure, drainage congestion, poor development planning and demolition of natural flood protection safeguards.
Yet other factors include high population density and improved income, both of which increase the demand for land, partly the reason for the sprawling development especially in urban areas of Anambra State. The land tenure system in rural communities is another factor. As a building cluster, there is a reduction in open spaces left for runoff to enter the ground. This concentrates flood by increasing its volume, intensity, and potential to harm the landscape. The borders and orientation of inherited land, for now, do not allow for reasonable drainage planning. On the other hand, poor drainage infrastructural development and poor land use development planning, result in arbitrary development culture and land take in areas that should normally be regarded as restricted, such as floodplains and urban greenbelts.
Dumping of solid wastes into drainage channels, block and congest floodway causing overtopping and overland flow. This is common in the urban environment and is responsible for much of urban erosion episodes. Other poor habits such as waste incineration in and around drainage channels also play a part by damaging the channels, which causes flow breaches, poor termination of drainage is also a key trigger of gullies the manual pointed.
Land loss from flooding and erosion is a common sight in both rural and urban areas of Anambra State. The loss of urban green belts to building and infrastructure and excessive ground clearing are other triggers of erosion. There is also a common feature of flood diversion as a result of uncoordinated conveyance facilities and obstructive development.
Flood and erosion control initiatives by individuals are common in all communities, but they are easily overwhelmed by a combination of natural and man-made predisposition factors. Sometimes, these factors exacerbate the problem of flooding and erosion through poorly installed ad hoc components, low-quality material input, and poor construction. Considering the high tempo of buildings in Anambra State, crammed into small land areas and the increasing demand for buildings, housing developments, roads and parking lots, gardens and lawns should begin to replace the paved surfaces as a control measure for the runoff generated crisis as well as green scaping rooftops with planting.
The manual disclosed that Sachet pure water, nylon bags and other plastic packaging materials remain a challenge as they block the little existing drainage channels. The big problem is the method of disposal, when they are dropped on the ground, as is always the case, plastic materials enter the soil and impregnate it. Research shows that it takes 500 years for plastics to decay. The major impact of plastic bags on the environment is that it takes many years for them to decompose. In addition, toxic substances are released into the soil when plastic bags perish under sunlight and, if plastic bags are burned, they release a toxic substance into the air causing ambient air pollution. Discarded plastic bags from our throw-away society end up blocking storm drains and culverts, impeding the flow of water and worsening bank erosion. Since plastics do not decay, they block the infiltration of water into the soil. This has certainly added to the flooding problems in Anambra State and will get worse unless consumers change their plastic disposal habits. It proposed for the public to avoid plastic by bringing reusable bags to grocery stores, switch from disposable to reusable drinking bottles, use a ceramic coffee mug, bring reusable containers, and reduce consumption of single-use plastic bags, straws, cups and other items.
On sand and stone mining in Anambra State, the manual noted its harmful impact on the environment. Sand and gravel are used extensively in construction and their extraction has increased. This adds to erosion and flooding because it requires the removal of the earth to retrieve resources from below the surface. It removes the trees that are essential to maintaining the soil. River sand is preferred for construction because it requires less processing, but it has a huge cost to the river and those living around it. Excessive sand mining can change the river course, erode banks and lead to flooding. Drainage channels are blocked because of sand excavation. The drainages are filled up with sand to allow easy passage of trucks and afterwards left like that. After years of earth quarrying and profit-making by individuals, the communities pay the price through the loss of their productive land to erosion as well as flooding. Controlling mining activities will go a long way in preventing soil degradation. This can be achieved through the reduction of sand consumption by optimizing the use of existing buildings and infrastructures. Recycled building and quarry dust material can be a substitute for sand as well as straw and wood.
A green belt is a policy and land-use zone designation used in land-use planning to retain areas of largely undeveloped, wild, or agricultural land surrounding or neighbouring urban areas. Encroachment into marginal lands and greenbelts due to Urban sprawl results in the clearing of vegetation which leads it prone to erosion and flooding. communities should therefore encourage green belts as has been adopted by countries such as Kenya for erosion control. During rainfall, wastes are dumped inside drains which leads to blockage of channels, causing flooding and erosion. Also burning refuse inside the channels weakens the walls, causing breaches that could result in new gullies. The plastic component should be collected for either recycling or other safe modes of disposal. Littering the environment with raw plastics renders the soil impervious, which increases runoff yield.
The manual advised for the end to bush burning because, in addition to reducing soil fertility, destroying the floor litter that protect the forest soil, it weakens the adhesion of the soil particles, loosens and makes them susceptible to flood transport. Grasses help to stop the rate at which water runs down the soil, when these grasses are removed due to fire, the soil is exposed to excessive water which in turn leads to flooding and erosion.
As a panacea to environmental sustainability, community roads must have at least surface drainage channels that must terminate safely into a stable receiving environment. Surface drainage channels are concerned with removing all water that is present on the pavement surface. The drainage helps to intercept the large quantity of the surface water flow and also breaks the continuity of flow thereby reducing the velocity of water and preventing erosion The drainage shortfalls are worse in the rural areas where the roads and footpaths have become drainage channels and storm sewers, as observed in many incidents of sheet erosion. Rainwater and flood should be put to good use, such as in meeting domestic water needs, agriculture and irrigation. The members of the communities should use reservoirs to collect and store water from their rooftops. Communities should make it compulsory for people to harvest runoff generated from their compounds in catchment pits within detention ponds strategically located outside their compounds. Catchment pits are locally constructed by digging ditches to some certain depth; water is retained and absorbed by the soil.
Despite the foregoing, therefore, the partnership between the Nigeria Erosion and Watershed Management Project (NEWMAP) and the Governor Willie Obiano-led administration has yielded monumental results as both authorities embarked on a mission to recover and save the environments from further degradations. To this end, NEWMAP in the control and management of flood and erosion crisis in Anambra state has seen the resettlements of displaced persons, massive works and remedial actions on erosion sites across the state. Many houses and other public buildings that would have been eroded were saved by its quick response and interventions and the Project Coordinator attributed the success recorded to the leadership of Governor Willie Obiano and the support of the legislature as well as respective Ministries, Departments and Agencies of government. According to Ivenso, “NEWMAP has responded promptly and proactively to erosion issues thereby putting smiles on melancholic faces whose properties were hitherto threatened by the hydra-headed monster called erosion. He emphasised that solid waste management, prohibition of sand and stone mining, prohibition of deforestation, protection of greenbelts, proper waste disposal system, prohibition of bush burning, proper execution of construction works, to mention a few, could serve as veritable solutions to flood and erosion control; there is a dire need also to report new projects that negate stipulated building standards and causing gully erosions in Anambra state”
The successor agency to NEWMAP is expected to drive the mandate by leveraging the instruments of state and the goodwill of the people. Ivenso noted that the governor aptly captured collective social responsibility for all in protecting and safeguarding the ecology when the governor said “ individuals and communities must take ownership of protecting their environment.” Ivenso explained that the support and commitment of the people will make a difference today and for future generations.
• Emeka Achebe is the communication officer for Anambra NEWMAP