Assimilative capacity

Assimilative capacity in hydrology is defined as the maximum amount of contaminating pollutants that a body of water can naturally absorb without exceeding the water quality guidelines and criteria. This determines the concentration of pollutants that can cause detrimental effects on aquatic life and humans that use it. Self-purification and dilution are the main factors effecting the total amount of assimilative capacity a body of water has. These algae have a high biochemical oxygen demand and reduce the available oxygen for other aquatic organisms. Close monitoring of the assimilative capacity or rivers is needed in order to stop eutrophication which can result in the loss of many aquatic organism. == Atmosphere ==

Assimilative capacity of the atmosphere is defined as the maximum load of pollutants that can be added without compromise of its resources. Meteorologists calculate assimilative capacity through the atmosphere using ventilation coefficient or through the pollution potential. The ventilation coefficient is calculated by multiply the mixing height (the height at which vigorous mixing of gasses occur) with the average wind speed. == Uses to determine management of environments ==

Assimilative capacity is used as a monitoring guideline for sustainable growth of city regions. Assimilative capacity allows governments to understand how much pressure a region is under. Working within the assimilative capacity means that regions will be constructed with future stability in mind. “An assimilative capacity study develops specific scientific modelling to support and assist municipalities and other legislative authorities in predicting the impacts of land use”. United States In the United States legislation on assimilative capacity as a guideline for the maximum amount of pollutants to be added to bodies of water comes from each individual state and from the environmental protection agency. Assimilative capacity is a quantitatively useful concept codified in the Clean Water Act and other laws and regulations that is unrelated to the perception of an environmental crisis. Assimilative capacity specifically refers to the capacity for a body of water to absorb constituents without exceeding a specific concentration, such as a water quality objective. Water quality objectives are set and periodically revised by regulatory agencies, such as the Environmental Protection Agency (EPA), to define the limits of water quality for different uses, which include human health, but also other ecologically important functions, wildlife habitat, irrigated agriculture, etc. For example, if the irrigation water quality objective for salt is 450 mg/L of total dissolved solids, the assimilative capacity of a body of water would be the amount of salt that could be added to the water such that its concentration would not exceed 450 mg/L. India India uses assimilative capacity in management of land, water and air. Though each have largely varying assimilative capacities due to variations in type of pollutants and the difference in dilution dispersion and chemical and biological breakdown in differing environments. == Comparison to accommodative capacity ==

Assimilative capacity has been critiqued as to the value it adds as a tool for creating guidelines in hydrology. There is a large amount of ambiguity in the definition as it is subjective. It has been questioned as to what exactly statements such as whether harmful to aquatic organism means “death of individual organisms, elimination of food chains, or a change in energy flow patterns”. Accommodative capacity has been suggested to remove ambiguity as uses of it have been more greatly defined in quantitative numbers. == See also ==