Chevak

Created: 2014-02-03 08:48:49
Modified: 2014-02-03 08:49:34

DESCRIPTION OF AREA CONTAINING SITE:

The Chevak site is located on a raised area approximately 1/3 mile & 300° NW of the town dump.  Taking the road past the dump, then off road to the NW past a lake and marshy area.  The 50m2 grid is located in an area of rolling tundra at the top of a flat rise in the land.  Lower areas with water, ponds and lakes characterize the surrounding area.  The vegetation is a mix of grasses, moss, lichen and low bush berries.   The 50mx50m grid, established in 2009, is marked with survey stakes at 10m intervals.  The grid center (N61.53, W165.62) contains continuous soil temperature & soil moisture sensors at ‘above permafrost’ & ‘just below surface’ levels.  An air temperature sensor also records on a 30 min continuous cycle.  The grid was established in 2009 through a cooperative agreement with Yukon River Inter-Tribal Watershed Council & the U.S. Geological Survey, with assistance from Chevak Native Village’s Environmental Coordinators.

SAMPLING DESIGN AND METHOD:

The specific location of the Chevak site was selected using Traditional Ecological Knowledge of permafrost distribution and depth, followed by on-site ground truthing.

The grid consisted of 50 survey stakes at 10-meter intervals, creating a 50mx50m square grid with a maximum of 100 data points.  Active Layer measurements were taken manually every 5m.  The measurements were taken at the lowest surface level within about 0.3m of the designated point.  The "surface level" was determined to be the top of the low-lying vegetation (i.e. moss, lichen, low-bush berries). 

[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 2009 and is located at grid center. The station monitors air temperature, soil temperature & soil moisture.

The HOBO micro station was installed at the grid center.  A ~30cm2 hole was dug down to the permafrost layer. One set of soil moisture and soil temperature sensors were placed just above the permafrost layer and out of water at (45cm) and one set just below surface level.  Soil samples were cut from each level (2x2in 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 10m, recorded at grid center.