EUTROPHICATION

Eutrophication is the process whereby lakes become oversupplied with nutrient leading to excessive growth of algae and various unpleasant consequences.
It is a natural process that occurs to all lakes over time as the weltering of rocks and soils from the surrounding catchment area leads to an accumulation of nutrients in the water and associated segment.
Young lakes usually have low levels of nutrients and correspondingly low level of biological activities.Such lakes are referred to as been OLIGOTROPHIC.Older lakes usually have high levels of nutrient and correspondingly high levels of biological activities.Such lakes are referred to as been EUTROPHIC.
CAUSES OF EUTROPHICATION

-Natural run-off of nutrient from the soil or the weltering rocks.
-Run-off of inorganic fertilizers(containing nitrates and phosphate).
-Run-off of manure from farms(containing nitrates,phosphate and ammonia).
-Run-off from erosion(following mining,construction work or poor land use).
-Discharge of detergents(containing phosphate).
-Discharge of partially treated or untreated sewage(containing nitrate and phosphate).
EFFECTS OF EUTROPHICATION
-An increase in plant and animal biomers.
-An increase in growth of rooted plant e.g reeds.
-An increase in turbidity(cloudiness).
-An increase in rate of segmentation.
-Decrease in specie diversity.
-Change in dominant biota.
CONSEQUENCES OF EUTROPHICATION

-Increased vegetation may impede water flow and the movement of boat.
-The water may become unsuitable for drinking even after treatment.
-Decrease in the amenity value of the water(e.g it may become unsuitable for water sports such as sailing).
¬-Disappearance of commercially important species such as trouts.
CONTROL OF EUTROPHICATION

-Using tertiary sewage treatment method to remove phosphate and nitrates before discharge of the effluence into the rivers and lakes.
-Directing waste water away to lakes to rivers and the sea.
-Aerating lakes and reservoirs prevent oxygen depletion particularly during algal bloom.
-Removing phosphate rich plant materials from affected lakes.
-Removing phosphate rich sediment by dredging.
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