Venetie

Created: 2014-01-31 12:44:11
Modified: 2014-01-31 12:50:29

DESCRIPTION OF AREA CONTAINING SITE:

Venetie is located on the north side of the Chandalar River, 45 miles northwest of Fort Yukon. The local name of the grid site area is Grass Lake. Throughout the area were open “pools” or “plugs” w/o grass that were likely the last standing water in the lake, remnants of the drainage location. After being unable to penetrate the clay layer, the site purpose was transferred from an Active Layer study to a soil moisture comparison study. With the area being an old lake that had dried, it was determined to use the study to gauge if the loss of soil moisture causes a decrease in the active/organic layer thickness, like the drying of a sponge. Does the loss/gain=rate of thaw? The 50mx50m grid, established in 2010, is marked with survey stakes along the *** and *** sides in 5-meter intervals. The grid center (N67.03, W146.02) contains continuous soil temperature & soil moisture sensors at above clay layer & just below surface levels. An air temperature sensor is installed on a stake near grid center. All sensors collect and store data on a 30-minute continuous cycle. The grid was established in 2010, with assistance from the Venetie Village Council, in the second year of a cooperative agreement with the Yukon River Inter-Tribal Watershed Council and the U.S. Geological Survey.

SAMPLING DESIGN AND METHOD:

The Venetie site was chosen to look at the loss of soil moisture and its effect on the organic layer rate of thaw.

The grid consists of 2 parallel lines of 10 survey stakes at 5-meter intervals, creating a 50mx50m square grid with a maximum of 100 data points. A compass was used to orientate the grid to a square. Measurements were taken manually every 5m and recorded on a fieldsheet. The measurements were taken at the lowest surface level within about 0.3m of the designated point, to minimize the questionable influence of tussocks on the AL measurement. The "surface level" was determined to be the top of the low-lying vegetation (i.e. moss, lichen, low-bush berries). Thaw measurements greater than 1.3m were noted, but not used in calculations, as of 2009. [CALM protocol suggests a grid size of 100mx100m, however a 50m2 grid was deemed acceptable due to difficult terrain and length of time for installation (personal communication Dr. V.Romanovsky).]

The soil climate station was established in early September 2010 and is located near grid center. The station monitors air temperature, soil temperature & soil moisture. The HOBO micro station was installed at the grid center. A ~30cm4 hole was dug down to the impenetrable clay layer at 37cm. One set of soil moisture and soil temperature sensors were placed just above the clay layer and one set just below surface level. Soil samples were cut from 31cm and 9cm (cubes) to be analyzed for soil moisture content. The HOBO pro v2 temp/ext temp sensor was installed, recording air temperature, near the grid center about one meter off the ground surface. The Hobo data logger is set to store data on 30min intervals for up to 428 days.

GPS points were taken at the four corners of the grid, as well as the center point where the sensors were located. Site elevation is 186m, recorded at grid center.