Water Resources, Wetlands And Freshwater Ecology

Changes in weather and climate have been known to profoundly influence water resources, a factor that increases the vulnerability of humans to infection. Generally, water resources involve all forms of fresh water needed for life's necessities, ranging from domestic needs to drinking, washing and cleaning, to agricultural needs involving food processing and irrigation, to other general needs.

Water for drinking comes from three sources (EP-HSE, 1995), generally: atmospheric water in the form of rain, snow or hail, and ultimately the source of drinking water in most rural areas of the third world countries where water is scarce (Okafor, 1985); surface water classified as rivers, streams, lakes or reservoirs and ponds (Duru, 1991 and EP-HSE, 1995); and ground water obtained from boreholes sunk into water-bearing rocks, or aquifers, or water that gushes out from rocks such as in springs (Enger et al, 1983 and ELE, 1992).

Fishing and fisheries are important occupation and operations that provide income, employment and proteins to Nigerians. In a situation of global warming of between 1.5 – 2OC, fisheries in Northern Nigeria, as in other northern parts of West Africa, would evidently be impacted (IPCC, 2007)

Water is indispensable. Its uses can be classified into five major categories (Enger et al 1983 and Okafor, 1985): domestic use; agricultural use (the major consumptive use of water); in-stream use (for hydroelectric power, recreation, and navigation); industrial use (for cooling industrial machines and equipment); and other uses (as a food source, for example).

Nigerians do not enjoy adequate water supply. The existing permanent water sources in the country such as the transboundary rivers are shared with other countries in the sub-region. The problem of water shortage is more prominent and severe in the northern areas of the country that have limited sources of water and harsh weather conditions.

The low-lying nature of Nigeria's 800 km coastline from Lagos to Calabar makes the region vulnerable to climate change. It is prone to sea-water intrusion into coastal fresh water resources and consequently inland fisheries and aquaculture are negatively affected. There is a high frequency of coastal erosion and flooding both climate change-induced forms of land degradation.

Drought – the total absence of rain for a very long time to the detriment of agricultural and other water related activities – is of concern. It leads to a distortion of seasonal patterns (which drastically affects agricultural yield) and increased incidence of soil erosion caused by excessive flooding and sporadic storm. It also kills livestock (two drought incidences in Nigeria in the 1960s and 1970s led to the death of millions of cows, goats and sheep, while the production of foodstuff such as cereals and other products were long affected). An increase in soil, erosion clearly affects water resources as siltation affects the level and volume of stream, lakes and ponds. Other factors such as increased desert encroachment and excessive heat have an inescapable impact on humankind and water-use.

The impact of changes in water resources will be overwhelming. It is obvious that rainfall variability, climate, soil, agrochemicals and diseases have a direct impact on water resources. Climate change has brought about changes in rainfall patterns, variability in rainfall, changes in water level, changes in the water level/volume of ponds, lakes, rivers and streams, and frequency of storms and drought. With increasing global warming and higher temperatures, a number of phenomena associated with water bodies in different ecological zones of Nigeria were identified.

Prominent among them are the following: