Marker Horizon Data at the Nisqually River Delta, Washington

SET-MH were installed in 2009 and 2010 with three replicates in Reference and Phase II and with two replicates (north-south) pairs in the 2009 restoration area (Units 1-4). SET-MH were 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. Marker Horizons consisted of a marker, usually white feldspar clay, so that the sediment that accumulated on top of the marker would be visible and measurable to the nearest millimeter. Together, SET-MH provide information on surface elevation changes due to surface accretion (MH) compared to changes that may be due to subsurface processes (such as root growth or groundwater swelling).