NWT RESEARCH DATABASE

Tags: physical sciences, water quality, active layer, permafrost, soil, landscape disturbance, climate change, slumping, benthic invertebrates, thermokarst

Objective(s): To monitor permafrost conditions in the Mackenzie Delta region; to examine freeze-back of the active layer and associated strength properties of freezing soil; to examine the influence of shrub removal on frozen ground and snow conditions at abandoned drilling-mud sumps; to investigate the effectiveness of different soil sampling protocols on describing contaminants in permafrost soils around drilling mud sumps; and to monitor the water quality of tundra.

Project Description: This licence is being issued for the scientific research application no. 978. The objectives of this research are to: 1) Monitor permafrost conditions in the Mackenzie Delta region; 2) examine freeze-back of the active layer and associated strength properties of freezing soil; 3) examine the influence of shrub removal on frozen ground and snow conditions at abandoned drilling-mud sumps; 4) investigate the effectiveness of different soil sampling protocols on describing contaminants in permafrost soils around drilling mud sumps; and 5) monitor the water quality of tundra lakes. Specific methods are as follows: 1) Permafrost conditions in the Delta region At each site, shallow temperature cables have previously been installed in the active layer, and near-surface permafrost and air temperatures are recorded by data loggers. Cables up to 20 m depth measure the permafrost temperatures. Snow depth and density will also be measured along 70 m transects using snow probes 2) Examining freeze-back of the active layer and associated strength properties of freezing soil The research team will collect information on snow using a snow probe, active-layer freeze-back using ground temperature cables, and associated soil strength properties with a penetrometer at two sites in representative terrain types of the outer Mackenzie Delta. Several meteorological parameters are being measured at two stations. Parameters include air temperature, wind direction and speed and snow depth. The field itinerary includes: 3) Examining the effects of shrub removal on the ground-thermal regime of drilling mud sumps The researchers will place instruments on three sumps with shallow ground temperature cables in summer 2009. They will remove tall shrubs on one of the drilling-mud sumps so that the effects on snow accumulation and ground thermal conditions can be evaluated. They will cut and remove shrubs in summer 2009. Snow depths and ground temperatures will be measured on a bi-monthly basis during winter 2009-2010 at this site and at nearby undisturbed sumps. 4) Soil sampling Three abandoned drilling mud sumps characterized by surface salt contamination will be visited. Soil sampling study designs will be compared for their effectiveness in evaluating salt contamination in areas of patterned ground (ice-wedges and hummocks). Field methods will include the collection of about 25 small (100 g) soil samples using a hand auger at each sump. 5) Monitoring lake water quality and aquatic quality of streams The research team will monitor the influence of natural disturbance (thaw slumping) on the water quality of tundra lakes. Fieldwork includes the collection of several small soil samples (100g) using a hand auger, and the collection of lake water samples (<1 L) at each study lake. Benthic samples will also be collected in two small streams, one affected by slumping and the other unaffected. Stream sampling will follow methods identified in the CABIN protocol (National sampling protocol for aquatic quality). Results of this research have been presented at several workshops and conferences in Yellowknife and Inuvik including the Overland Winter Travel workshop in Inuvik (March 2008), the Natural Resources Training Program Class - (2008). We are proposing that highschool and/or NRTP students and members of the Inuvik HTC be involved in the establishment of community oriented environmental monitoring sites in 2009. Furthermore, the researchers will continue an Environmental Monitor Training Program in summer 2009 with the goal of introducing HTC members to field data collection methods. The broad objective is to equip HTC members with the background and skills to participate in the long-term monitoring of environmental change and impacts of oil and gas infrastructure. The fieldwork for this study will be conducted in 76 sites around the Mackenzie Delta (specific locations can be obtained from the researcher or the Aurora Research Institute) from March 15 to November 30, 2009.