IDNR/OWR Stratton Dam Operations Glossary 2009

Glossary




Administrative Code Section 2030.80 Hazardous Navigation Conditions - Designated Restricted Boating Areas




In the event that the Department of Natural Resources determines the presence of conditions that make navigation of a body of water significantly dangerous to the public, the Director of the Department of Natural Resources may, in coordination with the federal government, designate Restricted Boating Areas on any affected body of water within the jurisdiction of the State of Illinois. This designation shall be made by public announcement in local media and by posting at local public boat launches and marinas, and the restricted area shall be physically marked by buoys, signs, manned watercraft or yellow police tape. This designation will remain in effect until the Director of the Department of Natural Resources determines that navigation is no longer significantly dangerous to the public, but in no case shall the designation remain in effect longer than 90 days. Recision of the Restricted Boating Area designation shall be publicly announced in local media and posted at local public boat launches and marinas and any markings shall be removed.










Degree freezing days - Degree freezing days are calculated by subtracting from 32° the average of the high and low daily temperature. Example: High Temperature 32° and Low Temperature 12° gives an average temperature of 22°. The Degree freezing days = 32° - 22°= 10°










Flows - is the volume of water that passes a given point within a given period of time. Flow is reported in cubic feet per second (cfs).










Gages - is a particular site on a stream, canal, lake, or reservoir where systematic observations of hydrologic data are obtained. The equipment measures and records gage height (stage), the water-surface elevation referred to some arbitrary gage datum. Stage-discharge relation is the relation between gage height (stage) and the volume of water per unit of time (discharge) flowing in a channel.










Lock - navigational structure to lift or lower boats; not used to move water










Storage - is the volume of water held in a reservoir or channel. Flows into the reservoir are greater than flows out of a reservoir when the reservoir is filling.










Watershed - an extent of land where water from rain or snow melt drains downhill into a body of water, such as a river, lake, reservoir, estuary, wetland, sea or ocean. The watershed includes both the streams and rivers that convey the water as well as the land surfaces from which water drains into those channels.