Wetland and Surface Water
What is Nutrition as Water Quality Indicator?

Nutrition stands for primary elements to suppot all lives on earth, and generally is represented by Nitrogen (N) and Phosphorous (P). Various discharged water, such as domestic wastewater and surface water from farmland, contains N and P. Surface run off from farmland, especially, are recently conserned as one of the major sources to introduce N and P due to the heavy use of fertilizer.

Excessive nutrition would have destructive impact expecially for the closed water system such as lakes and inland sea. Red tide and blue tide are well known as the result of those pollution.

Wetland, on the other hand, has function to get rid of these excessive nutrition from watershed by stabilization on plants and soils. This is one of the most notable function of wetland, and there are some cases to build artificial wetland to treat surface runoff at several places on the world. However, excessive nutrition could not be harmless to wetland, but accumulative effect eventually since those artificial environmental impact totally mess up the natural balance. There is actually some studies to suggest that the part of reason of alder expansion may be due to the changes of the amount and balance of supplied nutrition.