Surface elevation table (SET) measurements (raw data) from 6 marsh sites along the Rowley River, Rowley, MA. SET measurements are useful for determining the relative elevation change of marsh sediments. Precise measurements of sediment elevation in marshes is useful for determining rates of elevation change in response to changes in sea level.
SET sites are measured each spring and fall using a custom built surface elevation table. Measurement are made of the height of brass pins above the table. Relative changes in the surface elevation of the marsh can be calculated from the change of pin height overtime.
Four transects of three SETs were established in 2002. These are Holy Island, Morris Island, Law's Point and Old Levine's. Two additional transects of 3-SETs were established in 2005, using a different custom built table that relies on a rebar base. These are New Levine's and Infilling Pond. The middle SET of the Old Levine's transect (Old Levine's 2) was re-established in 2005 using the newer, rebar based SET (RSET).
For the original transects (2002), each SET has 6 positions relative to the location of the marker horizon (A-F). At each position there are 9 pins dropped to the marsh surface. The bearing of each position in relation to magnetic north is also recorded. For the 2005 rebar SET transects, each SET has 8 positions relative to the location of the Marker Horizon (1-8). At each position, 9 pins are dropped to the marsh surface. The length of pin extending above the table is measured and reported in centimeters. (This enables calculation of the length of pin between the table and the marsh surface, thus the elevation change over time between the constant position of the table and the changing marsh surface.) For more information on SET and Marker Horizons see: http://www.pwrc.usgs.gov/set
NOTES AND COMMENTS: This data is in a raw unprocessed format. Please note that the “SET position” in the data is a reference to the orientation of the SET table at each site. Position “A” refers to the orientation of the SET facing directly at the Marker Horizon plot, subsequent lettering continues in the clockwise direction.
Latitude and Longitude reported as decimal degrees in the NAD 83 Datum. Elevation is reported as NAVD 88, orthometric height (meters), and is measured at the top of the SET table from which pins are dropped. This raw elevation, taken from FastStatic measurements using a Trimble 4800 receiver and TSC-1 controller (from UNAVCO www.unavco.org), can be used directly with the SET pin measurements found in the dataset, to calculate the exact elevation of the marsh. Total pin length for the original SETs is 91.44cm, and pin length for the rebar based SETs 76.20cm. For example for Levine's SET 1 in Fall 2002, position A, pin 1 the value is 21.2cm (this is the height of the pin extending above the table). This means that between the measured top of the SET table at 2.067 m there are 70.24cm of pin (91.44cm -21.2cm). The marsh surface itself is therefore at 2.067m - 0.7024 m or 1.3646m elevation above mean sea level. For more information please contact Samuel Kelsey (firstname.lastname@example.org).
From 2015 on we used a Topcon Hiper V GPS using a fixed base and wandering rover to collect fast static measurements. Static data is post-processed in the lab using Topcon Magnet software and the NOAA Online Positioning User Service (OPUS) to correct positioning and reduce errors from a single base station. From 2020 on we used the Topcon Hiper V GPS with an RTK setup. RTK data is downloaded in real time using the MaCORS network for error corrections.
GPS measurements were taken on the top (highest point) of the SET pipe (the permanent pipe set to refusal in the ground). This is different than taking points on top of the SET plate. These measurements can be used to determine if the pipe has moved (subsided or bent). Accuracy is plus or minus 1cm in the x and y and 2cm in the z. The height of the SET arm must be added to these measurements to calculate SET table.
Original Surface Elevation Table
Cahoon, D. R., J. C. Lynch, P. Hensel , R. Boumans, B. C. Perez, B. Segura, and J. W. Day, Jr. 2002a. A device for high precision measurement of wetland sediment elevation: I. Recent improvements to the sedimentation-erosion table. Journal of Sedimentary Research. Vol. 72, No. 5. pp 730-733.
01) 15Aug2007 updates to EML level 4-5
02) Updated data through Spring 2007, added new levine's and infilling pond sites to dataset. 9/24/2007
03) Updated data through Fall 2009 and changed location data to reflect GPS data from 2009. 11/30/2009
Version 04: January 19, 2012, updated data and metadata through Spring 2011. Used MarcrosExportEML_HTML (working)pie_excel2007.xlsm 1/18/12 4:51 PM for QA/QC to EML 2.1.004).
Version 05: February 9, 2016, updated data and metadata through Spring 2015 to comply with importation to Drupal and LTER PASTA. Used MarcrosExportEML_HTML (working)pie_excel2007_Jan2015.xlsm 1/15/15 4:26 PM for QA/QC to EML 2.1.0.
Version 06: August 14, 2019, data and metadata updates to comply with importation to DEIMS7 and LTER Data Portal. Used MarcrosExportEML_HTML (working)pie_excel2007_Jun2019.xlsm 6/7/19 12:58 PM for QA/QC to EML 2.1.0
Version 07: February 18,2022 to update data and metadata through Fall 2021; data and metadata updates to comply with importation to DEIMS7 and LTER Data Portal. Used MarcrosExportEML_HTML (working)pie_excel2007_Jun2019.xlsm 6/7/19 12:58 PM for QA/QC of metadata.