“Rivers are major transporters of food, nutrients, soil, organic matter, plants and animals. This function is a critical element of aquatic ecology ensuring continual supply of sustenance throughout a river system. So …good water quality is paramount to the survival of aquatic life. Unfortunately rivers are equally…able…to carry(ing) pollutants such as chemicals, high levels of salt, phosphorus, and weeds which threaten aquatic eco-systems.
Aquatic life includes biota ranging from algae, bacteria, terrestrial and aquatic plants, macro-invertebrates, crustaceans, fish, reptiles, amphibians, birds and mammals. these are all important contributors to th the food web and when one component if affected it has consequences for all the other components.
Water quality depends on a range of factors and is very much influenced by activities undertaken in catchment areas. this may include the clearing of vegetation and sediment mobilisation, input of pollutants such as fertilisers and sewage and so on. Destruction of the riparian zone leaves rivers much more open to catchment influences. Riparian vegetation is one of the most important factors influencing water quality in this regard.
An unhealthy catchment likely to severely impact on water quality may have for example, a lack of ground cover and hill slope erosion, .. riparian areas may be eroding with very little or no aquatic vegetation or woody debris. If the riparian zone was re-instated and consisted of a mixture of grasses, shrubs and trees it would go a long way to improving water quality in a stream even if nothing else was done to the general catchment.”
from “riverways, Shortcuts to River Management Information in Australia.” p168. Greening Australia Ltd. 2005
For more information on Darwin Harbour and Water Quality please refer to http://www.nt.gov.au/nreta/water/aquatic/index.html for Darwin Harbour Region Report Cards.