Oregon Administrative Rules › Chapter 690 - WATER RESOURCES DEPARTMENT › Division 20 - DAM SAFETY › Section 690-020-0022 - Definitions

Current through Register Vol. 63, No. 7, July 1, 2024
Unless the context requires otherwise, the following
				definitions apply in OAR Chapter 690, Division 20:
(1) "Abutment" means a natural valley or
			 canyon side against which the Dam is built;
(2) "Acre-feet" means the unit of volume
			 equal to one acre covered with one foot of Water (325,851 gallons);
(3) "Annual Exceedance Probability Flood"
			 means the likelihood of a specific flood flow being equaled to or exceeded in
			 any given year at that specific location, expressed as a percentage;
(4) "As-built Drawing" means an engineering
			 drawing of a Dam as it was actually constructed, noting all differences between
			 original design and actual constructed condition;
(5) "Conduit" means a closed conveyance used
			 to release Water through a Dam;
(6)
			 "Core" means a soil of low permeability within an Embankment Dam;
(7) "Construct" has the meaning given to the
			 term in ORS 540.443;
(8)
			 "Constructing" has the same meaning as "Construct";
(9) "Crest" means the top of the
			 Dam;
(10) "Cutoff Trench" means a
			 trench excavated beneath the Dam Foundation and backfilled with low
			 permeability material to retard Water seepage;
(11) "Dam" has the meaning given to the term
			 in ORS 540.443;
(12) "Dam Failure"
			 has the meaning given to the term in ORS 540.443;
(13) "Department" means the Oregon Water
			 Resources Department;
(14)
			 "Director" means the Director of the Oregon Water Resources
			 Department;
(15) "Embankment" means
			 an engineered earth fill;
(16)
			 "Emergency Action Plan" or "EAP" has the meaning given to the term in ORS
			 540.443;
(17) "Engineer" means an
			 individual who is registered in this state and holds a valid certificate to
			 practice engineering in this state as provided under ORS
			 672.002 to
			 672.325;
(18) "Engineer of Record" means a
			 professional engineer registered in Oregon retained by a Dam owner to analyze,
			 plan, and design a Dam to current safety standards, to oversee safe
			 construction of a Dam, to supervise Modification or Removal of a Dam, or to
			 oversee corrective actions identified by the Department, or to otherwise
			 administer activities for a Dam;
(19) "Foundation" means the ground surface
			 upon which a Dam is constructed;
(20) "Freeboard" means the vertical distance
			 between the high-water level in the reservoir and the low spot on the
			 Crest;
(21) "Gate" or "Valve" means
			 a permanent device for regulating Water flow through the Dam;
(22) "Hazard Rating" means the categorization
			 of a Dam established by the Department based on the potential damage to life,
			 property, or public infrastructure downstream of a Dam in the event of a Dam
			 Failure;
(23) "Height" means the
			 maximum height of the Dam above natural ground as measured at the maximum
			 section along the Dam's longitudinal axis;
(24) "High Hazard Rating" or "High Hazard"
			 has the meaning given to the term in ORS 540.443;
(25) "Inflow Design Flood" or "IDF" means the
			 peak flood flow that the Engineer of Record will design to safely pass over or
			 through the Spillway;
(26) "Low
			 Hazard Rating" or "Low Hazard" means that if a Dam were to fail, loss of life
			 would be unlikely, and damage to property or public infrastructure would not be
			 extensive;
(27) "Maintenance
			 Action" has the meaning given to the term in ORS 540.443;
(28) "Modification" means changes to a Dam
			 that have a potential impact on the safe functioning of the dam, are to an
			 extent that the modified dam structures no longer conform to the original
			 design, and do not include modifying Dam Height, performing Maintenance
			 Actions, or Removal of a Dam;
(29)
			 "Person" has the meaning given to the term in ORS
			 536.007;
(30) "Potentially Unsafe" has the meaning
			 given to the term in ORS 540.443;
(31) "Pressurized Conduit" means any pipe
			 that penetrates into a Dam so that there is hydrostatic pressure due to the
			 location of a Gate, Valve, or pipe connection;
(32) "Probable Maximum Flood" or "PMF" means
			 the largest flood that could occur at a specific location, determined by the
			 most severe set of atmospheric, soil moisture, and snowpack conditions that are
			 reasonably possible at that location;
(33) "Removal" means demolishing all, or a
			 portion of, the Dam structure permanently preventing storage of Water and
			 allowing safe and natural passage of flood flows downstream;
(34) "Significant Hazard Rating" or
			 "Significant Hazard" has the meaning given to the term in ORS
			 540.443;
(35) "Soil Filter" means
			 soil with a gradation designed to inhibit movement of adjacent, finer grained
			 soils;
(36) "Spillway" means any
			 structure constructed to bypass Water, including flood waters, to prevent Water
			 overtopping the Crest;
(37) "State
			 Engineer" means an Engineer employed by the Department that is either the
			 director or a principal assistant working for the director as described in ORS
			 536.032;
(38) "Tank" means a fully-enclosed (bottom
			 and sides) hydraulic structure made from metal, reinforced concrete, rigid
			 fiberglass, or plastic that provides its own Water-sealing and structural
			 stability;
(39) "Toe Drain" is a
			 drainage structure designed to collect and remove seepage Water from the toe of
			 the Dam and to discharge this Water in a manner where it can be
			 measured;
(40) "Unsafe" has the
			 meaning given to the term in ORS 540.443;
(41) "Water" means water or
			 wastewater;
(42) "Zoned Embankment"
			 means an Embankment Dam with a Core of low permeability materials, Soil Filter
			 materials, drainage, and other materials placed to improve performance and
			 safety of the Dam.
Statutory/Other Authority: ORS
				  536.027,
				  540.488
Statutes/Other Implemented: ORS
				  540.443