Abstract:
Water content measurements were made continuously from 15 bore holes at an experimentally disturbed and undisturbed site at Scott Base to measure the amount of water loss from permafrost, to compare changes in the soil ice/moisture content profiles and to study soil climate and soil hydrology relationships. An experimental site was created near Scott Base and monitored from December through till
... mid-March. A 20 x 20m plot area was created. The unfrozen active layer on half of the area was removed by bulldozer to create a disturbed area. Fifteen holes were drilled, 9 in the disturbed area and 6 in the undisturbed. Some aluminum tubes were inserted into the holes drilled into the ground. Measurement of the water content of the permafrost down to about 120 cm were then made using a neutron probe. Alongside the disturbed site was an undisturbed site in which tubes were also inserted. After the ground was scraped, the ice in the permafrost began to thaw and the extent of the thaw and ground subsidence was noted in ensuing years by measuring the height from the top of the tubes (in the disturbed site) to the ground surface. The depth of all holes drilled varied between 1-1.5m. Soil samples obtained during the core drilling were weighed, oven dried and re-weighed and the water contents calculated for calibration of the neutron probe measurements.The unfrozen soil was excavated in 5cm layers and placed in plastic bags to prevent mixing and loss of soil water and replaced after the aluminium access tubes had been installed. In two holes, temperature probes were inserted into the soil to monitor temperature continuously. In the remaining holes, 1-1.5m aluminium tubes with 50mm diameter were inserted to allow neutron probe measurements of water content to be made. In order to relate the permafrost changes to energy input, other climatic measurements were made nearby including incoming and reflected solar radiation, net radiation, wind speed, soil heat flux and temperature recording equipment were set up in the disturbed and undistrubed areas for continous recordings to be made. The rate of water loss by evaporation was measured using miniature lysimeters. 
