Page:Niger Delta Ecosystems- the ERA Handbook, 1998.djvu/38

What is the Environment? However, it is only possible to understand the human impact on the environment if we understand that:

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Only then can we understand how the environment influences the way people live, and how mankind influences the landscape: only then can we understand the dynamic relationship between the two.

3.2ANALYSING A LANDSCAPE

Looking at any landscape and trying to understand it means analysing its components and understanding why they are there and what they are. Why is that forest there and why does it have special characteristics? Why is that farmland as it is? Why is that town in that position? What is the relationship between the forest and the farms? What will the landscape look like in six months, or in ten, twenty and a hundred year's time?

Analysing a landscape is best approached in eight steps, each being necessary to an understanding of the next.

3.2.1 GEOLOGY AND TOPOGRAPHY

This includes altitude, and the global and continental position of a landscape.

In the case of the Niger Delta it is important to realise that it is flat and at sea level. It is made up of sand and silt brought down by the Niger/Benue river system to the Bight of Benin on the West African coast, which is in the tropics. Much of the sand is spread along the continental shelf and thrown back onto the shore by ocean currents to form the characteristic barrier islands.

3.2.2 CLIMATE

This depends on latitude, continental position and altitude, and on both local and regional topography, such as nearby mountains. A knowledge of the climate is essential to an understanding of the Niger Delta, as a Tropical Rainy Climate.

3.2.3 HYDROLOGY AND WATER QUALITY

Natural hydrological characteristics are a function of geology, topography and climate. Thus in any given place at any given time, water may arise either locally, as stored ground water or rain, or from outside as upstream water or downstream tidal pressure. There are the daily tidal variations, in addition to seasonal change: also there are the subtle relationships between fresh and salt-water. 36