GSJ: Volume 12, Issue 12, December 2024

ISSN 2320-9186 47

GSJ: Volume 12, Issue 12, December 2024, Online: ISSN 2320-9186
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River Basin Network Channel and Flood Menace Control in Greater Port Harcourt, Rivers
State.
Ogboeli G. P. N., Chilaka, S. N. & Dan, I. C.
Institute of Geoscience and Environmental Management, Rivers State University, Port Harcourt1-2
Institute of Natural Resources, Environment and Sustainable Development, Uniport Choba, Port Harcourt, Nigeria3

Corresponding Author: Goodluck.ogboeli@ust.edu.ng

Abstract
Because of its low-lying terrain, enormous river network, fast urbanization, and the consequences
of climate change, flooding is a frequent and destructive issue in the Greater Port Harcourt Area
(GPHA), Rivers State, Nigeria. Because GPHA is located in the Niger Delta, an area with a
complicated hydrological system of rivers, streams, and wetlands, it is vulnerable to flooding,
which could endanger the residents' economic, health, and safety. In addition to investigating the
possibilities for better flood management through improved river basin management and
channelization technologies, this study looks at the function of the network channels in river basins
in flood control. It specifically looks into how altering the natural river channels might improve
the control of floodwater flow, lessen urban flooding, and lessen the negative effects of flood
hazards on communities who are already at risk. According to the results, flood risks in GPHA
may be considerably decreased while the area's resistance to future flood occurrences is increased
through sustainable river basin management, which incorporates both nature-based and artificial
solutions. In order to protect populations, preserve livelihoods, and promote long-term sustainable
development, the study suggests a thorough framework for managing flood risk that incorporates
river basin channelization with urban planning, infrastructure development, and climate adaption
strategies.
Keywords: River basin management, flood control, channelization, Greater Port Harcourt, flood
hazards, urbanization, climate change adaptation, sustainable development, flood resilience.

Introduction
In Rivers State, Nigeria's Greater Port Harcourt Area (GPHA), flooding has become one of the
most urgent environmental issues. Due to its low-lying terrain, complex network of rivers and
streams, high rainfall, tidal influences, and rapid urbanization, Port Harcourt and the surrounding
areas are especially vulnerable to frequent flooding. The Niger Delta is an ecologically sensitive
and flood-prone region (Emoh & Ume, 2013). The Bonny River, the New Calabar River, and other
tributaries are among the major river systems that encircle the city and have a substantial impact
on the hydrological dynamics of the area. The control of floodwater flow in the area depends
heavily on these rivers, which are a part of the Niger Delta river basin. However, a mix of human

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GSJ: Volume 12, Issue 12, December 2024
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and natural forces have weakened their ability to manage floodwaters, resulting in frequent and
destructive flood disasters.
Flooding in Greater Port Harcourt has resulted in a considerable number of fatalities, community
uprooting, property and infrastructure damage, and disruption of local economies throughout the
years. Significant environmental deterioration has also resulted from it, impacting ecosystem
services, fisheries, and agricultural output. Furthermore, especially during the rainy season, the
severity of flood events has increased due to inadequate drainage infrastructure and flood control
devices. The region's natural ability to absorb and attenuate flooding has been diminished as a
result of urban sprawl's continued encroachment on wetlands and natural floodplains. Residents in
vulnerable locations now face an even greater risk of flooding due to the poor condition of flood
control infrastructure, including dikes, levees, and drainage channels (Oruonye, 2016).
The interaction between the region's river basin network and increasing urbanization is mostly to
blame for the Greater Port Harcourt Area's susceptibility to flooding. In order to control water flow
and lessen the risk of flooding, the river basin network—which is made up of rivers, streams,
wetlands, and related floodplains—is essential (Ogboeli et al, 2024). However, the ability of these
rivers to store water and regulate flow has decreased as a result of the alteration of their natural
routes, the construction of roads and buildings on floodplains, and other urban encroachment.
Furthermore, sand mining, careless garbage disposal, and inadequate land-use planning have
blocked river channels, making it more difficult for them to efficiently transport floodwaters.
Inadequate flood control systems, tidal surges raising river water levels, and excessive rainfall
during the wet season are the main causes of flooding in the Greater Port Harcourt Area.
Historically used as natural drainage systems, river channels are now frequently overloaded,
causing overflow into nearby communities. The risk of flooding has been made worse in certain
places by the encroachment of informal settlements onto the riverbanks. Simultaneously, the
effects of climate change and rising sea levels have made floodwater management more difficult
because rising tides and heavier rainfall increase the likelihood of riverine and coastal floods
(Ogboeli et al., 2023).
Enhancing the management of the river basin network is a crucial tactic for reducing flood risks
in Greater Port Harcourt. Managing a river basin entails regulating water flow by building or
repairing embankments, flood barriers, channels, and flood diversion systems (Udo, 1970). Flood
risks can be decreased, floodwater can be better diverted away from susceptible areas, and the
area's ability to withstand extreme weather events can be enhanced with the implementation of
suitable river basin management techniques. Reducing flood risks, preventing urban floods, and
enhancing community resilience in flood-prone locations are all possible outcomes of river
channelization, which is the alteration of river channels to enhance water flow and storage.
The importance of better flood control infrastructure, such as efficient river channel management,
in flood reduction has been emphasized in a number of studies and papers. Adelekan (2010), for
instance, pointed out that poor flood management techniques and the deterioration of river systems
worsen flooding in the Niger Delta region, which includes Greater Port Harcourt. One major factor
in the region's frequent flood dangers is the improper channelization and upkeep of river basins.
In a same vein, Emoh and Ume (2013) stressed the necessity of integrated flood management that
takes river basin management into account as well as sustainable urban development, especially
in quickly urbanizing places like Port Harcourt.

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GSJ: Volume 12, Issue 12, December 2024
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Flood management initiatives in Nigeria have long included the installation of flood control
structures such levees, dams, and flood diversion channels. However, these initiatives'
effectiveness is frequently hampered by issues with governance, bad planning, insufficient money,
and environmental sustainability. Incorporating ecological factors into the management of the river
basin network and making sure that human activities do not compromise the natural floodplain
functions are crucial for effective flood control in Greater Port Harcourt. The plan to control flood
risks in the area must also take into account the effects of climate change, such as increasing sea
levels and more intense rainfall events.
This study intends to investigate the potential of river basin network channelization and enhanced
flood management strategies to lower flood risks and improve resilience in the Greater Port
Harcourt area, given the intricate relationships between urban development, flood hazards, and
river basin dynamics. This study looks at the connections between flooding and river basin
management in an effort to shed light on how river channels might be effectively managed to
reduce flood risks and support sustainable urban growth in the Greater Port Harcourt Area.
Material and Method
Location and extent
The Niger Delta is a vast network of rivers, wetlands, and coastal areas that includes the Greater
Port Harcourt area. The actual Port Harcourt is situated where the Bonny and Port Harcourt rivers
converge. Low-lying marshes, swamps, and floodplains that are vulnerable to flooding are features
of the geography, especially during the rainy season (April to October) and in years with large
tidal surges (Udo, 1970). With densely inhabited places like Port Harcourt's city center and less
developed outlying areas like Oyigbo, Okrika, Ogu–Bolo, Obio–Akpor, Ikwerre, Etche, and Eleme
local government areas, the GPHA encompasses a broad spectrum of urban, peri-urban, and rural
areas. Its size is around 1,900 km² (734 mi²), and as of 2009, it has a population of 2 million. Poor
drainage infrastructure, uncontrolled urban growth, and climate change-induced increases in sea
level and rainfall intensity all contribute to the region's susceptibility to flooding (Adelekan, 2010,
Ogboeli et al 2023). The planned metro area will be built through extensive plans that implement
and enforce rules for infrastructure development and service delivery aimed at raising people's
standard of living and overall well-being. The new metro region is anchored by the Port of Onne,
Port Harcourt City, and Port Harcourt International Airport.
The Greater Port Harcourt City Development Authority (GPHCDA) was established on April 2,
2009, with the passage of Greater Port Harcourt City Development Authority Law No. 2 of 2009.
Developing the new Greater Port Harcourt Master Plan (2008) metropolitan area and supporting
the master plan's implementation are among its responsibilities.

Result and Discussion

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GSJ: Volume 12, Issue 12, December 2024
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Figure 1: River Basins in Greater Port Harcourt

Based on the results in Table 1 and Figure 1, Greater Port Harcourt can be separated into 12 river
basins. Ntawogba, Ogechie, Okrika, Otamiri, Rumuokoro, Rumuolumeni, Woji, Bolo, Elelenwo,
Lower Imo River, and New Calabar River were among these basins. With 3053 sq km, or 57.16%
of the total, Amadi Creek was found to have the largest geographical extent of all the basins under
study. With 570.65 sq km, or 10.67%, the New Calabar River Basin ranked second, while the
Lower Imo River Basin, with 412.67 sq km, or 7.73%, ranked third. The three basins with the
smallest geographical areas were Rumuolumeni (8.84 sq km), Ntawogba (29.46 sq km), and Bolo
(54.49 sq km).

Table 1: River Basins in Greater Port Harcourt

S/N Name Spatial Area Percentage (%)
Covered (Sq. km)
1 Amadi Creek Basin 3053.00 57.16

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2 Bolo Basin 54.49 1.02

3 Elelenwo Basin 100.85 1.89
4 Lower Imo River Basin 412.67 7.73
5 New Calabar Basin 570.05 10.67
6 Ntawogba Basin 29.46 0.55
7 Ogechie Basin 387.04 7.25
8 Okrika Basin 117.23 2.19
9 Otamiri Basin 292.86 5.48
10 Rumuokoro Basin 181.85 3.40
11 Rumuolumeni Basin 8.84 0.17
12 Woji Basin 132.55 2.48
Total 5340.89 100.00

Areas under high danger of flooding include the regions of Amadi Creek, Bolo, Elelenwo, Lower
Imo River, New Calabar River, Ntawogba, Ogechie, Okrika, Otamiri, Rumuokoro, Rumuolumeni,
and Woji basins. Due to their existence and extremely low elevation, these important rivers, which
pass through most of the Greater Port Harcourt districts under consideration, present a considerable
risk. There are numerous farmlands and natural areas here, and there aren't as many buildings. This
area is particularly susceptible to flooding because of the outdated homes, the absence of a drainage
system, and the solid waste that is dumped into the waterways.
Because most of the settlements in this zone are isolated and have limited infrastructure, it is quite
difficult to reach this terrain. Since the majority of the settlements in this area are either connected
by local bridges or are reachable via footpaths, dug-out canoes, motorized boat access, Okada
(motorbikes), and occasionally local bridges during floods, outside assistance is a little
challenging.
The river basin network's insufficient ability to manage the volume of water during heavy rains is
one of the main sources of floods in the area. Surface and riverine floods are caused by the buildup
of water caused by inadequate river channels, clogged drains, and inadequate maintenance of the
current flood control system. Particularly, during times of heavy rainfall or tidal surges, the
overflow of these river systems frequently inundates areas along the riverbanks, floodplains, and
coastal zones.
Notably, the remoteness of these regions discourages the development of stronger structures,
increasing the number of mud and wooden homes. Since they live close to waterways, most of
them work as fishermen. There are also a few farmers who cultivate crops and cattle, as well as
small-scale traders. The traditional believers in this region (the ancestral home) view floods as
divine occurrences for which ceremonies may be carried out to lessen their effects.
This is believed to deter early warning signs and prevent them from moving to safer areas. Because
they lack the social capital needed to be resilient to disaster recovery, communities in this area
continue to suffer greatly from flooding. The places with medium damage/moderate danger of
flooding are along streams such as Mgbuosimiri in Obio/Akpor, Nkarahia in Ikwerre, Obibi in
Etche, Okojagu in Okrika, and Ogu in Ogu-Bolo, to mention a few.
Additionally, the vulnerability of towns in these locations is increased by the lack of
comprehensive flood management techniques and appropriate floodplain zoning restrictions.

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Flood control features including levees, embankments, and dikes are either nonexistent or badly
built in many areas of the Greater Port Harcourt Area, underscoring the need for a more sustainable
and integrated approach to river basin network management.
The study emphasizes how flood hazards in GPHA have been made worse by urban development,
poor drainage infrastructure, river basin degradation, and environmental mismanagement.
Additionally, it emphasizes how crucial efficient river channelization is to boosting flood
management capabilities, increasing the area's resistance to severe weather, and encouraging
sustainable urban growth. The study looks at the potential and problems of managing river basin
networks, such as the necessity of community involvement, climate change adaptation, and
coordinated governance. The advantages of integrated flood management systems that take into
account both ecological and infrastructure solutions are also covered, including their positive
effects on the environment, society, and economy.
Conclusion and Recommendations
A comprehensive strategy that incorporates sustainable urban design, infrastructure development,
climate adaption tactics, and river basin network management is necessary for effective flood
control in the Greater Port Harcourt Area. If river basin channelization is correctly designed and
carried out, it can significantly reduce the risk of flooding, safeguard communities that are at risk,
and increase resilience to future floods.
Recommendations for improving flood control in the region include:
Comprehensive River Basin Planning: In addition to engineered infrastructure, a coordinated,
multi-stakeholder approach to river basin management should be implemented, emphasizing
sustainable, nature-based solutions.
Infrastructure Investment: In addition to routine maintenance programs, government and private
sector investment is required in flood control infrastructure, such as retention ponds,
embankments, and flood diversion channels.
Zoning and Urban Planning: To prevent development in flood-prone areas and to preserve natural
flood management systems, including wetlands, effective zoning laws should be implemented.
Community Engagement: To make sure that flood mitigation strategies meet local needs and
objectives, local communities should be included in planning for flood management and disaster
preparedness initiatives.
Climate Change Resilience: To make sure that infrastructure can survive the future effects of
climate change, such as rising sea levels and extreme weather events, long-term flood management
planning should take climate change projections into account. Greater Port Harcourt can lessen its
susceptibility to floods, enhance the standard of living for its citizens, and promote sustainable
development in the area by putting these strategies into practice.

References:
Adelekan, I. O. (2010). Vulnerability of Nigerian coastal communities to flooding: Implications
for climate change adaptation strategies. The Geographical Journal, 176(3), 211-220.

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GSJ: Volume 12, Issue 12, December 2024
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Emoh, F. I., & Ume, O. (2013). Flooding and urbanization in Nigeria: A case study of the Port
Harcourt metropolis. Nigerian Journal of Social Sciences, 21(2), 78-89.
Ogboeli, G. P., Iyama, W. A & Onuegbu W. (2023). Incidences and Trend of Marine Accident
Fatalities in Various River Routes Connecting the Major Sea Ports of Nigeria. International
journal of research and innovation in applied science (ijrias), 8(4): 109-122.
Ogboeli, G. P., Brown I. & Onuegbu W. (2024). Evincing the social and economic impact of inland
waterways transportation in the development of the Port Harcourt metropolis. International
Journal of Hydrology, 8(1): 27-35.
Oruonye, E. D. (2016). Flooding and urban resilience in the Greater Port Harcourt Area: A spatial
analysis. Environmental Management and Sustainable Development, 5(2), 11-19.
United Nations Environment Programme (UNEP). (2015). Environmental vulnerability and flood
risk in the Niger Delta. UNEP, Nairobi.

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