Adapted from the Lake Ontario-St. Lawrence River Study
DESIGN RANGE - The range of factors (including expected water levels) taken into consideration when making an investment decision.
DIGITAL ELEVATION MODEL (OEM) - A digital image of geographical features consisting of a grid, in which the colour of each cell reflects an average elevation above or below sea level.
DIGITAL ORTHOIMAGERY - Computer-assisted cartography technique allowing representation of surface features with the positional accuracy of a map, through elimination of errors due to camera or sensor orientation and terrain relief.
DIGITAL ORTHOPHOTO - A computer-rendered image representing surface features, in which inaccuracies due to camera or sensor orientation and terrain relief have been removed. Such an image combines the positional accuracy of a map with the image quality of a photograph.
DIKE - A wall or earth mound built around a low lying area to prevent flooding.
DIVERSIONS - A transfer of water either into the Great Lakes watershed from an adjacent watershed, or vice versa, or from the watershed of one of the Great Lakes into that of another.
DRAINAGE BASIN -The area that contributes runoff to a stream, river, or lake.
DROWNED RIVER MOUTHS (also known as estuaries) - The place where lake and river waters mix. They provide valuable habitat for spawning fish, nesting and migrating birds, and many rare or specialized plants. These wetlands typically have deep organic soils that have accumulated due to deposition of watershed-based silt loads and protection from coastal processes (waves, currents, seiche, etc.).
DUNE - a mound or ridge of sand formed by the action of wind or waves.