Lake Albert (Campbell Park)
Map: Groundwater monitoring locations in Campbell Park
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 Campbell Park
Acidity concentrations in the groundwater at Campbell Park are high at all sites due to the exposure and oxidation of acid sulfate soils during the drought. Although acidity is still present at all sites, it is likely acidity will decrease over time, as the acidity will be neutralised by the alkalinity which is being produced as the groundwater recovers.
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 Campbell Park
Alkalinity was low, and at times, absent in the three acidic sites in Campbell Park during the drought. Since the water level has returned, alkalinity has improved at Site CP 3S and is starting to reappear at CP 2S and CP 4S. 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 Campbell Park
There were three low pH groundwater sites at Campbell Park, on the Western Margin of Lake Albert, during the drought. 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, although still remains below desirable levels (pH > 6.5) at CP 1S, CP 2S and CP 3S.
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 Campbell Park
Salinity in the shallow groundwater at Campbell Park is naturally much higher than the overlying surface water due to accumulated dissolved salts from weathered soil materials. At Campbell Park, fresher surface water conditions since the inundation of these sites has allowed groundwater salinity to decrease.