Kotlik

Created: 2014-02-03 08:56:36
Modified: 2014-02-03 08:57:26

DESCRIPTION OF AREA CONTAINING SITE:

The Kotlik site is located along the Kotlik Slough, in the Yukon-Kuskokwim Delta, approximately 250° West of Kotlik cemetery.  The 50m2 grid is in a moderately well drained area of open flat tundra.  Some willows are spread across the surrounding area, however none fall w/in the grid site.  Two sample points are in standing water.  The 50mx50m grid, established in 2009, is marked with survey stakes at 10m intervals.  The grid center (N63.02, W163.56) 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 Kotlik Tribal Council’s Environmental Coordinator.

SAMPLING DESIGN AND METHOD:

The specific location of the Kotlik 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, 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 1m 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 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 ~30cm4 hole was dug down to the permafrost layer at 44cm. One set of soil moisture and soil temperature sensors were placed just above the permafrost layer and one set just below surface level.  Soil samples were cut from 42cm and 6cm (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 0m, recorded at grid center.