Surface Elevation Table Data at the Nisqually River Delta, Washington

Surface Elevation Tables (SETs) were installed in 2009 and 2010 using permanent, deep rods driven down into the soil with a demolition hammer, typically about 60-80 feet. The top of the rod lies near the sediment surface, with a receiver end. A Surface Elevation Table is a portable mechanical leveling device that attaches to the receiving end at the top of the deep rod. The SET arm includes a bubble level and a notched collar that allows for the arm to be aligned precisely and repeatedly in the cardinal directions.
SETs were installed as triplicates in Reference, Phase II, and as north-south pairs in the 2009 restoration area (Units 1-4). Each SET location was read repeatedly at regular, at least annual intervals. Reading SETs consisted of measurements for nine pins facing the four cardinal directions for a total of 36 measurements per SET, per sampling event. Each pin was measured to the nearest millimeter.