Nick Ashton-Jones, with Oronto Douglas and Susi Arnott

Name: Niger Delta Ecosystems: the ERA Handbook — The Natural Sand-Barrier Islands of the Niger Delta
Author: Nick Ashton-Jones, with Oronto Douglas and Susi Arnott

Niger Delta Ecosystems: the ERA Handbook… (1998)

Summary

“Niger Delta Ecosystems: the ERA Handbook — The Natural Sand-Barrier Islands of the Niger Delta”, published in 1998, is a work by Nick Ashton-Jones, with Oronto Douglas and Susi Arnott. It explores elements such as erosion, sediment and barrier.

Quotes from Niger Delta Ecosystems: the ERA Handbook… (Nick Ashton-Jones, with Oronto Douglas and Susi Arnott)

Nick Ashton-Jones, with Oronto Douglas and Susi Arnott, Niger Delta Ecosystems: the ERA Handbook… (1998)

“ In some places, earth walls or dykes have been built to contain floods, and sometimes riverbeds are now actually higher than the surrounding land. When such rivers break their banks, the floods can be catastrophic and may not only destroy fields and buildings but cause the deaths of thousands of people.
However, just as forest clearance can accelerate erosion and increase the sediment load of a river system, the construction of dams often reduces this load by physically trapping sediment and therefore reducing the amount of sand available for deposition downstream. ”

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Source: Wikisource

Nick Ashton-Jones, with Oronto Douglas and Susi Arnott, Niger Delta Ecosystems: the ERA Handbook… (1998)

“ Clearing an area of forest vastly reduces the amount of vegetation protecting the soil from rainfall damage. It also largely removes the 'sponge' that moderates the release of rainwater into river systems. The result is increased erosion and increased sediment loads carried by rivers, and therefore an increase in the amount of sediment available for deposition. ”

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Source: Wikisource

Nick Ashton-Jones, with Oronto Douglas and Susi Arnott, Niger Delta Ecosystems: the ERA Handbook… (1998)

“ Longshore drift spreads it to the East and West, where it joins sediment contributed by lesser river systems such as the Imo and the Osse (Ovia) .
The sand spreads as a band of islands along the coast. They are mostly 'true islands', completely surrounded by water, be it the Atlantic itself or the water of lagoons and of the creeks that twine their way around islands formed further inshore. Where they form in the mouth of an estuary, they may be called sand bars.
Sand thus thrown up by the Atlantic often forms a high beach, behind which streams running from inland may form a lagoon. ”

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Source: Wikisource

Nick Ashton-Jones, with Oronto Douglas and Susi Arnott, Niger Delta Ecosystems: the ERA Handbook… (1998)

“ Long-shore Drift: the 'backwash' of a wave is always at right angles to the waterline, straight back out to sea. However wave direction is almost always at an angle to the shore, so that the 'swash' runs diagonally up the beach. This means that sediment tends to be carried along the shoreline. Longshore drift is responsible for the erosion of some shorelines, and the deposition of features such as spits and barrier beaches.
Sand Bars: ridges of submerged sand crossing the mouths of estuaries as a result of long-shore drift. ”

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Source: Wikisource

Nick Ashton-Jones, with Oronto Douglas and Susi Arnott, Niger Delta Ecosystems: the ERA Handbook… (1998)

“ Within the Niger Delta, the Beach Strand ecosystems are unique to the Sand Barrier Islands. The beach strand sub-ecozone can be broken down into three bands: the beach that is exposed at low tide, the beach ridge that has risen above the high tide mark ”

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Source: Wikisource

Nick Ashton-Jones, with Oronto Douglas and Susi Arnott, Niger Delta Ecosystems: the ERA Handbook… (1998)

“ Secondly, especially where river flow is sluggish, some of the increased sediment load may settle out on the riverbed. As the riverbed rises, the volume available within the banks for the actual flow of water is reduced and again the risk of overflow is increased. In many areas of the world, including parts of China, India and Europe, forests have been cleared and entire landscapes devoted to agriculture for hundreds or even thousands of years. ”

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Source: Wikisource

Nick Ashton-Jones, with Oronto Douglas and Susi Arnott, Niger Delta Ecosystems: the ERA Handbook… (1998)

“ Mangrove forests are also thriving on the East and Southeast edges of the island, where they are protected from the prevailing south-westerly winds and waves by the sand spit that has developed as a result of long-shore drift. The West side of the island is exposed to stronger winds and currents ”

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Source: Wikisource

Nick Ashton-Jones, with Oronto Douglas and Susi Arnott, Niger Delta Ecosystems: the ERA Handbook… (1998)

“ This balance between deposition and erosion is affected by long-term geological factors. Over shorter time periods, variations in rainfall and in human activities will differentially affect different parts of individual islands and different sub-ecozones. The two human activities that have the most profound impact on this balance are forest clearance and the construction of dams. ”

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Source: Wikisource

Nick Ashton-Jones, with Oronto Douglas and Susi Arnott, Niger Delta Ecosystems: the ERA Handbook… (1998)

“ Firstly, because the forest 'sponge' is no longer acting, rainfall runs straight off the land into streams and rivers. These may now disappear during the dry season, but break their banks or overflow in the rainy or wet season. ”

Nick Ashton-Jones, with Oronto Douglas and Susi Arnott

Summary

Quotes from Niger Delta Ecosystems: the ERA Handbook… (Nick Ashton-Jones, with Oronto Douglas and Susi Arnott)

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