Field Water Quality Parameters
Water quality parameters such as electrical conductivity (EC), pH or redox (Eh) that can be readily measured in the field have been used to investigate groundwater discharge to streams. This is particularly the case if the shallow groundwater is relatively saline and is a significant contributor to the salt load of the stream. Run of river salinity surveys have been used to define the key reaches of the River Murray in South Australia with large groundwater-induced salt accessions (Porter, 2001). The groundwater contribution to stream flow can be estimated, based on measurements of groundwater salinity and stream flow. Monitoring of stream salinity in conjunction with stream flow can provide useful information on the temporal variability of salt loads, and by inference groundwater discharge.
Field surveys using other water quality parameters may also be useful in characterising groundwater discharge. In coastal catchments where acid sulfate soils are an issue, surveys of stream acidity can be a simple and effective technique of mapping key reaches receiving shallow acidic groundwater.
References
- Porter B, 2001. Run of river surveys. A method of measuring salt load accessions to the River Murray on a km by km basis 8th Murray-Darling basin Groundwater Workshop. Victor Harbour, SA, September 2001