Base flow in many of the region's streams comes from groundwater and so the quality of groundwater affects the quality of our waterways.
Groundwater is also often used as a source of drinking water or farm water supplies.
So it's important to monitor the groundwater level and quality throughout the region and the movement of any contaminants through aquifers (the layers of rock containing groundwater). Council staff also monitor the quality of groundwater around potential sources of pollution such as landfills, industrial sites where storage tanks may have leaked, and industries spreading wastes on land. They also monitor groundwater below agricultural land to evaluate the effects of land management activities such as stocking rates and fertiliser application.
Potential pollutants to groundwater include hydrocarbons (from any leaking fuel tanks holding oil, diesel, petrol, or bitumen), ammonia and nitrate (from landfill leachate or farming activities), or chloride and sulphate (landfill leachate, drilling mud disposal).
Where groundwater is used as a supply of drinking water, high nitrate levels can cause adverse health effects (especially in babies). Elevated levels of nutrients (nitrate, ammonia, phosphate) in groundwater contribute to algae growths in streams, and indicate poor management of land use activities, such as inappropirate fertilizer application rates.