Setting Water Quality Resource Condition Targets for the Rivers and Streams in the Darwin-Litchfield-Bynoe Region
Yusuke Fukuda and Simon Townsend
Aquatic Health Unit
Environment Protection Agency Program
What is NAP?
The $1.4 billion National Action Plan for Salinity and Water Quality (NAP) and the $3 billion Natural Heritage Trust (NHT) are major national programs which aim to improve the management of Australia's natural resources. They represent the biggest financial commitment to environmental action in Australia's history and are playing an important role in protecting and enhancing Australia's unique biodiversity, the viability of rural and regional communities and the future of our agricultural industries. Both the NAP and the NHT are partnerships between all levels of community and Government, working together to protect our environment and natural resources, and sustain our agricultural industries and regional communities. The programs are driven by single regional plans, developed by local communities and supported by government and the best available science to improve the management of natural resources on a regional scale.
What is the Project About?
In conjunction with the regional plans for the Northern Territory, this project aims to set the water quality resource condition targets that can be used by natural resource managers to assess water quality in the region. It presents the typical or expected values of water quality for freshwater rivers and streams in the region for the early Dry season (April to May). The targets can be used in the the Territory’s Integrated Natural Resource Management Plan for river water quality maintenance and assist local community groups to monitor and assess whether or not water quality is being maintained.
What is Water Quality?
Water quality refers to a number of different water characteristics. This project focussed on nitrogen, phosphorus, turbidity, Electrical Conductivity (EC), pH, alkalinity, temperature, Dissolved Oxygen (DO), gilvin and chlorophyll a as indicators of water quality. Their meaning and importance are as follows:
| Nitrogen | An important plant nutrient. Too much nitrogen in the form of oxidised nitrogen and/or ammonia can lead to excessive plant growth. |
| Phosphorus | An important plant nutrient. Too much phosphorus in the form of filterable reactive phosphate can lead to excessive plant growth. |
| Turbidity | A measure of the light scattering property of water as a result of material suspended in the water. It affects the amount of light available for photosynthesis by aquatic plants including algae. |
| EC | A measure of the amount of ionic materials (salts). High conductivity often indicates spring water from limestone aquifers. |
| pH | Amount of the concentration of hydrogen ions. A fundamental measure that influences metal solubility and toxicity, and affects an organisms ability to absorb minerals and nutrients. |
| Alkalinity | The capacity of the water to neutralize acid and buffer the water. |
| Temperature | Fundamental affecting all the other water characteristics. |
| DO | Essential for all aerobic plant and animal processes. Prolonged periods of oxygen depletion can result in death of fish and other animals, and too much oxygen is a sign of increased plant/algal biomass due to nutrient enrichment. |
| Gilvin | The coloured components of dissolved organic matter in water mostly sourced from the decomposition of plant material by bacteria. |
| Chlorophyll | The green pigment of plants used in photosynthesis. It is used as an index of the amount (biomass) of algae. |
