Floods – An Architect’s View

Architect Tony Asare writes…


Tomorrow will be 8 years since I wrote the piece below. Just check, nothing really has changed… Horror Story

FLOODS – AN ARCHITECTS VIEW
Tony Asare | June 22, 2010

 

Introduction

The rains are in again and Accra is again being flooded after a few hours of heavy downpours. The bad news is that it is bound to get worse as the years go by. Flooding is not peculiar to Ghana and may not be attributed to bad planning alone. Recent floods in London, India, China, Bangladesh and some other countries indicate that beyond planning regimes we may need to do more. A careful study of the causes, remedial actions and improvement of our disaster management should be properly coordinated and synchronized to reduce the loss of life and property in the country and some other Urban Areas often affected by floods. The role of stakeholder institutions such as The Meteorological Services, National Disaster Management Organization (NADMO), Environmental Protection Agency (EPA), Town and Country Planning and Municipal, Metropolitan and District Bodies, The Ministries of Works, Houses and Water Resources, Professionals in the built industry i.e. Ghana Institute of Architects, Planners, Surveyors need to be orchestrated in a coordinated manner to reduce the effects of the aforementioned organizations and institutions.

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Weather Forecasting

The relevance of weather forecasting has been relatively relegated to the background. Often the approaching storms are announced only a few hours before they hit the country. If the weather warning is in the middle of the night residents may not even get adequate forewarning. Mostly on international networks such as the BBC and CNN etc. there is very little mention of Ghana’s weather since they basically group it by region and possibly group West Africa together which is not locally specific. Ghana would have to be more specific and speak the language that Ghanaians can understand with regards to the weather. On our networks, the mention of the weather occurs on even fewer occasions. In fact, those often very directly affected may not even have access to this information.
It is interesting to note that on occasions that these networks mention the weather of the West African coast is when its weather results in hurricanes in the Caribbean and South eastern portions of the United States of America. However, weather forecasting affects our agriculture, air travel, construction of roads and buildings; and for a developing country we need to train, equip, improve and increase the distribution of weather measuring instruments or personnel.

 

Flooding

There are several ways by which inundation of run-off occur during rainstorms. These include Localized Flooding, Environmental and Development or Infrastructure in induced flooding. The factors that induce flooding in each case vary considerably and often aggravated when these combinations occur simultaneously. Local flooding is often confined and may not affect a whole neighborhood that collects run-off with the inability to exit. This could be due to poor planning of site, marshy soils, poor drainage and some other very local conditions. In addition, there are sites which are generally flood prone by virtue of their nature due to soil types, i.e. clay soils with low absorption properties. Land forms, sites located in valleys etc.

It is interesting to note that some locality names often are indicative of that e.g. Fadama (banks of a river, riverside) Dzorwulu (Deep gauge or valley etc) in such areas, when the rivers or drains burst banks flooding is more severe because immediate areas are already flood prone. The development of structures or settlements near these water courses also increase run-off and therefore increases chances of flooding.
Development induced flooding usually occur due to increase in infrastructure development e.g. houses, roads, walkways, etc.

Percolation is reduced with increasing infrastructural coverage. In open areas about 50 percent of storm water is able to infiltrate whilst 10 percent runs-off the rest is evaporated. When there is a 20 percent of land is covered by walkways or roads etc. run-off increase to 20 percent, infiltration and evaporation reduces to 42 and 38 percentage respectively.

 

Policy Direction

Building vertically makes available more space for percolation and therefore reduces incidence of flooding for a fixed area of building and site. More greens should be encouraged during development to enhance percolation. As settlements increase, areas closer to drains, rivers should be clearly reserved or for green area development and drainage. Laws governing thoroughfare of drains should be promulgated to reduce the incidence of flooding etc.

 

Environmental Impact Assessment / Management Plan

The role of EPA in flood alleviation planning cannot be overlooked. After the construction of the Aburi-Adenta and N1 Roads, flash floods should increase around settlements along the road. This brings into question Environmental Management Plans by consultants/contractors and its monitoring. Post construction monitoring should include all stakeholders i.e. consultants, Road Users, contractors, settlements occupants etc., specialized department e.g. Hydrology Department, National Disaster Management Organization (NADMO).

For instance, before the construction of the N1 from Tetteh Quarshie to Maalam Junction it is expected that an Environmental Impact Assessment was done indicating how its impact would possibly affect the immediate environs and settlement. It is clear that the increase of the size of the road would eventually increase storm water collection therefore run-off would increase. Looking at the terrain from the Dimples Traffic Lights all the way to the Tetteh Quarshie interchange the lowest point is around the Villagio Buildings and the African Regent Hotel. The residents therefore should have engaged the Road Contractor and briefed on what the plans are to mitigate potential flooding. The residents would then be in the position to monitor the Environmental Management plan after construction and verify its effectiveness.

As things stands now we shall wait till there is a disaster and the Former President’s Residence is flooded then it becomes headline news then the analysis starts on all radio stations.The preparation of the Environmental Management Plan should involve NADMO in order that as part of their future planning the new areas of potential flooding could be planned for.

National Disaster Management Organisation (NADMO)

Whenever flooding occurs, NADMO in most cases end up being in the firing line. Not reaching locations on time, inadequate and insufficient relief materials, lack of personnel and on and on and on. An important question to ask is when there are no floods what preparations are done to better equip relief management.

In instances, where roads and bridges are washed away or rendered unusable new strategies should be looked at. Capacity building in flood prone areas is an example. The organization should redirect efforts in training resident in flood prone area in basic safety and lifesaving methods. Additionally, NADMO could draw up programmes during dry seasons and undertake such construction techniques with the assistance of Ghana Institute of Architects, Engineers etc. the training should be given to those who live in the various flood prone areas and should include basic lifesaving techniques.

Disaster management stations should be established and equipped with inflatable boats, life jackets, blankets etc. and protected by the various MMDAs. This would reduce response time and augment the efforts of NADMO.

An improved data collection of areas and the development of maps showing progressively areas hit by floods should be undertaken. This information should be shared among all planning related departments and published to educate the public. This would advise developers on trends and possible danger zones to stay away from.

 

Construction Specification

Flooding is synonymous with failure of buildings and a lot of buildings collapse due to poor construction materials. In the northern Ghana where earth there is a relatively high percentage of construction, buildings can easily be washed away We need to take a second look at specification of buildings in rural flood prone areas and educate the settlers on improved building construction practices. A good mix of laterite-lime ratio would make these buildings more resistant to water and resilient than regular swish buildings. Regular sandcrete blocks are normally quite resilient to water or run-off.

Additionally, rendering or plastering such walls with cement sand does not bond properly. The advisable rendering which is known technically as mc2-cut-back is a mix of bitumen, sand and lime is not common and such very technical capacity would require an engagement of the people and the various assemblies.

 

Open and Protected Areas

Urban green open spaces are invaluable assets in maintaining ecologically healthy settlement mix. They bring character, protect wildlife and bring life into communities. Beyond these environmental factors, open areas are used during disasters to set up Disaster Management areas. Temporary storage spaces, camps or temporary accommodation etc. It should therefore be made mandatory that specific portions of settlement be set aside for this purpose and its alteration criminalized. Unfortunately, the sale of open areas in Ghana by some municipal authorities is done indiscriminately.

 

Conclusion

With emerging environmental concerns and the increase in the occurrences of flooding, it is certain that we have not seen the last of floods in Ghana. A lot of these ideas cannot be implemented without public private collaboration and the empowering of various institutions to properly. We may just go back to sleep when the rains go down and have another rude awakening when the rains come back again next year. This piece was written in May 2008 and does it not still sound it was written this morning? The demolition of buildings alone does would not stop the floods and its effectiveness has still not been measured and proven to the people of Ghana. There should be a more pragmatic and conscious effort to prevent the loss of life and property. Is somebody listening?

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