On the afternoon of Saturday, July 8, 2023, in the lovely township
of Ho, nestled amidst the gorgeous hills of Ghana's Volta Region, a disastrous
event occurred. A three-hour rainstorm turned the picturesque valley into a
flooded environment, causing major property loss and structure damage. As a
flood risk enthusiast and environmental scientist, I am profoundly concerned
about the risks of constructing on hills. In this blog post, we will look at
the risks, look at case studies, and talk about how local and national
governments, as well as individuals, can react proactively to avoid disasters
in the face of rapid population increase and urbanization.
The Risks of Building on Hills
Due to the geological and hydrological characteristics of hillside
terrain, there are inherent dangers associated with hillside construction.
Among the principal threats are:
Increased Flood Vulnerability
Hills serve as natural drainage channels, directing rainwater
downhill. As evidenced by the recent tragedy in Ho, development on these slopes
interrupts the natural water flow, resulting in greater flood risk.
Soil Erosion
Typically, hills have steep slopes that are prone to soil erosion.
Construction activities, such as excavation and vegetation removal, destabilize
the soil and increase its vulnerability to erosion. As sediment-laden water
flows into the valley, this erosion can increase flooding.
Landslides and Structural Instability
Hillsides are susceptible to landslides, particularly after
significant rainfall. Construction and excavation can weaken the hill's
stability, increasing the chance of catastrophic landslides. Moreover,
buildings constructed on unstable terrain may sustain structural damage or
collapse during such occurrences.
Infrastructure Overload
Often, hillside development outpaces the expansion of required
infrastructure. Typically, roads, stormwater drainage systems, and wastewater
management facilities are poorly constructed and poorly maintained. As the
population increases and more buildings are constructed, the strain on the
infrastructure increases, heightening the risk of floods and the potential for
damage to homes and public facilities.
Case Studies: Lessons from Hillside Development Gone Wrong
Numerous case studies from throughout the world illustrate the
dangers of constructing on slopes and its repercussions. Here are three
noteworthy instances:
Freetown, Sierra Leone
The devastating case study of Freetown, Sierra Leone, serves as a
poignant reminder of the consequences of building on hills without careful
consideration. In August 2017, heavy rains unleashed a catastrophic landslide,
resulting in over 1,000 fatalities and extensive destruction. The disaster was
largely attributed to the combination of unplanned urbanization on the
hillsides and widespread deforestation, which exacerbated the vulnerability of
the area to such an event. This tragic incident underscores the urgent need for
responsible land use practices, comprehensive urban planning, and the
preservation of natural ecosystems to prevent similar catastrophes in Ho and
other growing cities facing rapid population growth and urbanization.
Rio de Janeiro, Brazil
In January 2011, torrential rains triggered landslides in the hills
surrounding Rio de Janeiro, leading to widespread destruction and loss of life.
The city's rapid population growth had led to extensive hillside development,
with settlements encroaching on vulnerable slopes. The combination of heavy
rainfall, deforestation, and inadequate infrastructure exacerbated the risks,
resulting in a catastrophic disaster. This case study serves as a cautionary
tale, illustrating the consequences of uncontrolled hillside development.
Shimla, India
Shimla, a popular hill station in India, experienced severe flooding
in 2015 due to unchecked urbanization on its slopes. The construction of
buildings without proper planning and environmental considerations led to the
obstruction of natural drainage channels. Consequently, during intense
rainfall, the excess water could not escape, causing widespread flooding. This
case study emphasizes the need for holistic planning and sustainable
development practices to mitigate the risks associated with hillside expansion.
Interventions to Mitigate Flood Hazards
To mitigate the risks associated with building on hills, local and
national authorities must adopt proactive measures. Here are some key
interventions:
Public Awareness and Education
It is crucial to educate the local populace about the dangers of
building on hills. Community involvement programs, workshops, and educational
campaigns can assist citizens in comprehending the hazards, thereby developing
a culture of resilience and responsible development.
Early Warning Systems
Investing in early warning systems, such as weather monitoring,
flood detection, and landslide monitoring, can provide timely alerts to
residents and authorities, enabling swift evacuation and disaster response.
Early Intervention and Planning
Local and national authorities must implement and strictly enforce
effective land-use planning regulations. Before permitting any hillside
development projects, comprehensive analyses of their environmental impact must
be done. These evaluations should take slope stability, drainage patterns, and
the preservation of natural vegetation cover into account. Hillside development
dangers can be reduced by encouraging developers and inhabitants to follow
sustainable building practices and implementing hazard-resistant designs.
Grey Infrastructure Solutions
Investing in grey infrastructure, including the expansion of
drainage systems, the improvement of stormwater management, and the
construction of flood retention basins, can help decrease flood risks. Local
governments should prioritize the maintenance and cleaning of existing drains
to maintain their best performance during rainfall events. The construction of
flood control infrastructure, such as detention ponds, can hold and gradually
release excess water, so minimizing the intensity and impact of flooding
downstream.
Green Infrastructure Solutions
Promoting the integration of green infrastructure is essential for
reducing flood hazards in hillside communities. Keeping and enhancing natural
vegetation cover stabilizes slopes, decreases soil erosion, and increases water
absorption. Green roofs, permeable pavements, and rain gardens can enhance
water penetration and decrease runoff. In addition, preserving riparian zones
and building buffer zones along watercourses can provide natural flood
protection, protecting human settlements while keeping ecological balance.
The Important Role Individuals Can
Play
While local and national authorities play a crucial role in reducing
the dangers of constructing on hills in Ho, residents also play a key role in
safeguarding their community. Here are some instances of how residents might
contribute:
Awareness and Preparedness
Residents should educate themselves about the risks associated with
building on hills and be aware of early warning signs of potential hazards. By
staying informed and prepared, they can take proactive measures to protect
themselves and their properties.
Responsible Construction
If residents are considering building or renovating their homes,
they should consult with experts who can assess the safety and stability of the
hillside location. Following proper construction practices, such as adequate
soil stabilization, appropriate drainage systems, and adherence to building
codes, can help minimize risks.
Sustainable Land Use
Individuals should be mindful of the environmental impact of their
actions. Avoiding deforestation and promoting reforestation efforts can help
prevent soil erosion and enhance the natural resilience of the hills.
Additionally, residents can practice responsible waste management to prevent
clogging of drainage systems.
Community Engagement
Establishing neighbourhood associations or community groups focused
on disaster preparedness and resilience can foster a collective approach to
addressing the risks. Sharing knowledge, organizing drills, and collaborating
with local authorities can strengthen the community's ability to respond
effectively in times of crisis.
Reporting and Monitoring
Residents should report any signs of instability, erosion, or
potential hazards to the local authorities promptly. Regular monitoring of the
hillside areas can help identify early warning signs and trigger necessary
interventions before disasters strike.
By actively engaging in these measures, individual residents in Ho
can contribute to the overall resilience and safety of their community,
reducing the risks associated with building on hills and enhancing the town's
capacity to withstand future flooding events.
Final Words
The recent flooding in Ho, Ghana, serves as a stark reminder of the
perils associated with hillside development and rapid urbanization. By
examining case studies from around the world, we can understand the risks and
consequences of uncontrolled expansion on vulnerable slopes. To avert future
catastrophes, proactive interventions are necessary. Early intervention through
stringent land-use planning, along with the implementation of both grey and
green infrastructure solutions, can significantly reduce the vulnerability of
growing cities to flood hazards. It is essential for residents, local
authorities, and national government bodies to work together, prioritize
sustainable development practices, and adopt resilient strategies that balance
urban growth with environmental preservation. Only through collective efforts
can we safeguard our communities and ensure a sustainable future for
generations to come.
ABOUT THE AUTHOR
Michael Dabi is an experienced environmental scientist, lecturer, and researcher dedicated to identifying and mitigating pollutants' impact on the environment. With expertise in environmental science and a passion for writing, Michael brings a unique blend of knowledge and communication skills to his work.
He is currently pursuing a PhD in Environmental Science and has conducted research on various topics such as the effects of oil and gas exploration, mining activities, climate change, indoor air pollution, biodiversity, and conservation.
Beyond his academic pursuits, Michael offers consultancy services in program development, impact assessments, fish farming, book writing, proofreading, web development, and data analysis. He is committed to quality assurance and capacity building, consistently striving for excellence in his work.
Michael's contributions extend to numerous publications, including academic journals, books, and research papers. His blog serves as a platform for exploring environmental topics, providing insightful perspectives, and offering practical solutions for a sustainable future.
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