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11. Recommended Glossary
Pages 309-328

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From page 309... ... In fact, the National Research Council's Committee on Safety of Nonfederal Dams recommended in its 1982 report* to FE MA that "FEMA, with the help of ICODS, should develop a glossary of common terms for use in dam safety activities." The present committee, based on its review of the various sources of nomenclature and the members' experience, recommends the following glossary of terms to assist FEMA in implementing this recommendation. Read the entire page →
From page 310... ... CONSTANT ANGLE ARCH DAM An arch dam in which the angle subtended by any horizontal section is constant throughout the whole height of the dam. CONSTANT RADIUS ARCH DAM An arch dam in which every horizontal segment or slice of the dam has approximately the same radius of curvature. Read the entire page →
From page 311... ... ARCH BUTTRESS DAM See Buttress Dam. ARCH GRAVITY DAM See Gravity Dam. Read the entire page →
From page 312... ... SOLID HEAD BUTTRESS DAM A buttress dam in which the upstream end of each buttress is enlarged to span the gap between buttresses. The terms round head, diamond head, tee head refer to the shape of the upstream enlargement. Read the entire page →
From page 313... ... DESIGN FLOOD See Spillway Design Flood. DIAMOND HEAD BUTTRESS DAM See Buttress Dam. Read the entire page →
From page 314... ... HYDRAULIC FILL DAM An embankment dam constructed of materials, often dredged, that are conveyed and placed by suspension in flowing water. ROCKFILL DAM An embankment dam in which more than 50 % of the total volume comprises compacted or dumped pervious natural or crushed rock. Read the entire page →
From page 315... ... FIXED CREST WEIR See Weir. FLASHBOARDS Lengths of timber, concrete, or steel placed on the crest of a spillway to raise the retention water level but that may be quickly Read the entire page →
From page 316... ... NET FREEBOARD, DRY FREEBOARD, FLOOD ~EBOA~, or ~SIDUAL ~BOA~ iS the vertical distance between the estimated maximum water level and the top of a dam. GROSS ~EBOA~ or TOTAL ~EBOA~ iS the vertical distance between the maximum planned controlled retention water level and the top of a dam. Read the entire page →
From page 317... ... CREST GATE (SPILLWAY GATE) A gate on the crest of a spillway to control overflow or reservoir water level. Read the entire page →
From page 318... ... (GROSS CAPACITY OF RESERVOIR) The gross capacity of a reservoir from the river bed up to maximum controlled retention water level. Read the entire page →
From page 319... ... INTRADOS The curved downstream surface of an arch dam. INUNDATION MAP A map delineating the area that would be inundated in the event of a dam failure. Read the entire page →
From page 320... ... MULTIPLE ARCH DAM See Buttress Dam. NAPPE The overfalling stream from a weir or spillway. Read the entire page →
From page 321... ... NORMAL WATER LEVEL For a reservoir with a fixed overflow sill it is the lowest crest level of that sill. For a reservoir the outflow from which is controlled wholly or partly by movable gates, syphons or by other means, it is the maximum level at the dam to which water may rise under normal operating conditions, exclusive of any provision for flood surcharge. Read the entire page →
From page 322... ... An artificial lake, basin, or tank in RESERVOIR AREA The surface area of a reservoir when filled to controlled retention water level. RESERVOIR ROUTING The computation by which the interrelated effects of the inflow hydrograph, reservoir storage, and discharge from the reservoir are evaluated. Read the entire page →
From page 323... ... ROUND HEAD BUTTRESS DAM See Buttress Dam. RUBBLE DAM A masonry dam in which the stones are unshaped or uncoursed. Read the entire page →
From page 324... ... SOLID HEAD BUTTRESS DAM See Buttress Dam. SPILLWAY A structure over or through which flood flows are discharged. Read the entire page →
From page 325... ... TAILRACE The tunnel, channel, or conduit that conveys the discharge from the turbine to the river; hence the terms tailrace tunnel and tailrace canal. TAILWATER LEVEL The level of water in the tailrace at the nearest free surface to the turbine or in the discharge channel immediately downstream of the dam. Read the entire page →
From page 326... ... They are placed in interlocking patterns and are effective for high-energy dissipation. TUNNEL A long underground excavation usually having a uniform cross section; hence the terms headrace tunnel, pressure tunnel, collecting tunnel, diversion tunnel, power tunnel, tailrace tunnel, navigation tunnel, access tunnel, scour tunnel, drawoff tunnel, and spillway tunnel. Read the entire page →
From page 327... ... WEIR A low dam or wall built across a stream to raise the upstream water level. Termed fixed-crest weir when uncontrolled. Read the entire page →

From page 309...

... In fact, the National Research Council's Committee on Safety of Nonfederal Dams recommended in its 1982 report* to FE MA that "FEMA, with the help of ICODS, should develop a glossary of common terms for use in dam safety activities." The present committee, based on its review of the various sources of nomenclature and the members' experience, recommends the following glossary of terms to assist FEMA in implementing this recommendation.

11. Recommended Glossary Pages 309-328

11. Recommended Glossary
Pages 309-328