Map: Groundwater monitoring locations in Currency Creek
What is acidity?
Acidity is a measure of the acid (hydrogen ions) and dissolved metal ions (e.g. iron and aluminium) present in water bodies. Acidity is expressed as the volume of calcium carbonate (mg/L of CaCO3) required to neutralise any acid. Acidity build up occurs when the alkalinity or buffering capacity has been consumed.
Acidity at Currency Creek
Acidity was recorded in high levels at two sites Currency Creek during the drought. Acidity has decreased substantially since inundation but still persists in low levels. Monitoring of acidity at these sites will continue to observe the recovery of the groundwater.
What is alkalinity?
Alkalinity is a measure of the buffering capacity of water, or the capacity of the water to neutralise acids and resist pH change. It is expressed in milligrams per litre as calcium carbonate (mg/L as CaCO3) and is present in groundwater predominantly due to the weathering of carbonate minerals in the soils.
Alkalinity at Currency Creek
Alkalinity was low to absent in the two acidic sites in Currency Creek during the drought. Since the water level has returned, alkalinity has improved at both sites. The return of alkalinity indicates an improvement in the groundwater quality.
What is pH?
pH is an indicator of acidity or alkalinity. pH is a logarithmic scale and an increase or decrease of one pH unit is a 10 fold change. Neutral water has a pH of 7, acidic solutions have values between 0-6 and alkaline solutions have values between 8-14.
pH levels at Currency Creek
There were two low pH groundwater sites at Currency Creek. The low pH is a result of acidity produced as a result of the exposure of acid sulfate soils. Since these sites have been inundated, the pH has increased markedly, illustrating a trend of groundwater improvement at Currency Creek.
What is salinity?
Salinity is a measure of the amount of dissolved salts in the water. Saline water conducts electricity more readily than freshwater, so electrical conductivity (EC), measured in micro siemens per centimeters (uS/cm) is routinely used to measure salinity.
Salinity at Currency Creek
Salinity in the groundwater is naturally much higher than the overlying surface water due to accumulated dissolved salts from weathered soil materials. At Currency Creek, fresher surface water conditions since the inundation of these sites has seen groundwater salinity decrease.