SURFACE ELEVATION CHANGE, VERTICAL ACCRETION, AND SHALLOW SUBSIDENCE RATES INDICATED BY LOUISIANA’S COASTWIDE REFERENCE MONITORING SYSTEM (CRMS)

Louisiana’s Coastwide Reference Monitoring System (CRMS) is a network of 392 reference sites in the coastal zone that collect hydrology, vegetation, and soils monitoring data concurrently for assessment of coastal restoration projects. Surface elevation change and vertical accretion data have been collected semiannually since 2006 using the Rod Surface Elevation Table (RSET) and feldspar marker horizon methods. RSET rods were driven to refusal which was between 7.1 and 43.7 meters (23 to 143 ft) below the Holocene surface. Estimates of elevation change are within Holocene sediments down to depth of refusal. Vertical accretion is measured above a feldspar maker horizon at the wetland surface. At this time, rates of elevation change, vertical accretion, and shallow subsidence are calculated for over 200 CRMS sites. Current values and trends will be presented spatially and within the context of Louisiana’s coastal basins.