US Army Corps of Engineers
Portland District Website Website

Overview of controlling factor: Elevation / Depth / Bathymetry

Graphic depiction of elevation and habitat typesElevation and depth are measures of the height of a point on the surface of the sediment or soil of a location, expressed relative to a datum point (e.g., NGVD29, MLLW).


Bathymetry is a collection of depth points that represent the gradients of elevation and depth change along a surface. Changes to elevation/depth often alters the dessication stress and amount of light reaching the bottom for aquatic organisms.


The figure at bottom left shows a cross-sectional diagram of habitat types at various elevations in an estuary (based on Procter et al. 1980a). The figure at bottom right shows bank-to-bank bathymetry from the U.S. Army Corps of Engineers (2003-2004).

Stressors that affect elevation/depth/bathymetry:

  • Dredging
  • Extreme climatic events
  • Filling
  • Marinas and overwater structures
  • Seismic activity
  • Shoreline armoring
  • Volcanic activity

Graphic showing waterway information in colorEcosystem structures that are affected by elevation/depth/bathymetry:

  • Scrub-shrub forest
  • Emergent marsh
  • Mud / sand flats
  • Submerged aquatic vegetation
  • Shallow slope
  • Deep channel

Interactions and equations:


Contact information

Ronald Thom, Ph.D

Marine Research Operations, PNNL
1529 W. Sequim Bay Rd.
Sequim, WA 98382