New Zealand Journal of Marine and Freshwater Research abstracts
Nutrient concentration changes in the ground water beneath Taupo township following sewage reticulation
M. M. GIBBS
Taupo Research Laboratory
DSIR Marine and Freshwater
Department of Scientific and Industrial Research
P. O. Box 415, Taupo, New Zealand
Abstract
Reticulation of the sewage from Taupo township, New Zealand, proceeded in stages between 1974 and 1986, with initial stages servicing the central retail area and the streets closest to and parallel with the lake shore. Subsequent stages serviced streets further from the lake resulting in a progressive reduction in the volume of septic tank effluent entering the ground-water table, but not necessarily a corresponding reduction in the nutrient concentrations entering Lake Taupo. The rate of reduction of the nutrient load in the ground water entering the lake was a function of the original load, and the proportion of the ground-water recharge volume associated with the septic tank effluent water in each subcatchment. An estimated reduction of 60% in the DIN load on Lake Taupo from this source has occurred between 1978 and 1989. Consequently, reticulation of the sewage from Taupo township has had a beneficial effect on the quality of the inshore waters of Lake Taupo along most of the foreshore.
Keywords ground water; nutrients; nitrogen; phosphorus; sewage; septic tank; Taupo
New Zealand Journal of Marine and Freshwater Research, 1991, Vol. 25:153-161 0028-8330/2502-0153 $2.50/0 © Crown copyright 1991
Received 4 September 1990; accepted 12 March 1991
PDF file of entire paper: medium quality (548K); (scanned from paper original: notes about this process)
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