Geology and Hydrology of Flood Hazards: Terms and Definitions, Quizzes of Geology

Download Geology and Hydrology of Flood Hazards: Terms and Definitions and more Quizzes Geology in PDF only on Docsity! TERM 1 River DEFINITION 1 any channelized surface flow. normal flow defined within a channel TERM 2 Flooding Hazards DEFINITION 2 unlike other geologic hazards because they are readily quantified TERM 3 Creating Drainage Networks DEFINITION 3 water moves overland, follows shortest route, develops channel, end result is a network extended by headward erosion TERM 4 Drainage Basins and Divides DEFINITION 4 each network exists in a drainage basin, separated by divides. large basins made of many smaller basins, separated by continental divides TERM 5 Stream Piracy DEFINITION 5 when the headward erosion of a stream crosses a divide. steals the upper network of another TERM 6 Draining Patterns DEFINITION 6 sensitive to underlying rock. dendritic, rectangular, radial, trellis TERM 7 Antecedent Stream DEFINITION 7 existed before topography TERM 8 Superposed Stream DEFINITION 8 superimposed on older rocks TERM 9 Gradient DEFINITION 9 slope of a stream. vertical change/horizontal distance. high close to head, low close to mouth TERM 10 Longitudinal Stream Profile DEFINITION 10 implies a lower limit to gradient (and therefore erosion) TERM 21 Alluvial Fans DEFINITION 21 same as delta minus ocean. form when sediment-laden water enters a dry valley. TERM 22 Discharge DEFINITION 22 volume of water per unit time in a stream. how much water is flowing. width*depth*velocity. TERM 23 Stream Gaging DEFINITION 23 measure the stream channel type. monitor velocity and water level. TERM 24 Flooding DEFINITION 24 most destructive natural hazard in terms of frequency and lives lost. normal, natural, and cyclical but humans get in the way. TERM 25 Types of Floods DEFINITION 25 upstream (flash)= small stream, begin and end quickly. downstream (riverine)= large stream, begin and end slowly. TERM 26 Hydrograph DEFINITION 26 plots of stream discharge. depends on time period chosen. short used for flooding. long used for water resources TERM 27 Rating Curves DEFINITION 27 calibration curves for specific locations of specific streams. allows estimates of discharge from gage height TERM 28 100 Year Flood DEFINITION 28 just means 1% chance per year, not 100 years between floods TERM 29 Recurrence Interval DEFINITION 29 year plus one, divided by rank. TERM 30 Levee DEFINITION 30 control structure. walls parallel to channel on floodplain intended to keep water off floodplain. levee war TERM 31 Flood Mitigation DEFINITION 31 control runoff, retention structures (pond outside ccmills) TERM 32 Problems with Buyouts DEFINITION 32 perceived vs actual value, infrastructure costs, people who won't move TERM 33 HMS Challenger DEFINITION 33 explored world's ocean but only a few hundred data points TERM 34 Modern Oceanography DEFINITION 34 after ww2. improvements in technology (sonar, magnetometers, computers) and surplus equipment (ships) TERM 35 Oceanic Sedimentation DEFINITION 35 no sediments older than mesozoic age. near continents= fine grained detrital rocks, graded bedding. not near continents= shallow water has limestone, deep water has cherts. carbonates become soluble under pressure TERM 46 Barrier Islands DEFINITION 46 large sand bars that stand above sea level. subject to migration, constant motion TERM 47 Creating Inlets DEFINITION 47 channels cut by overwash waves TERM 48 Beach Stabilization DEFINITION 48 attempt to keep beach in current location and form. hard= working against beach processes. soft= with beach processes (replenishment and advanced structures) TERM 49 Groins DEFINITION 49 intercept longshore drift. walls perpendicular to beach to trap sand on one side. TERM 50 Jetties DEFINITION 50 maintain inlet. walls perpendicular to beach to block longshore current. results in the island migrating TERM 51 Breakwaters DEFINITION 51 block waves. walls parallel to beach to stop waves TERM 52 Seawalls DEFINITION 52 armor the dune. since beachfront property is highly desirable. results in the beach going away TERM 53 Beach Replenishment DEFINITION 53 importing sand. expensive, short lived TERM 54 Storm Effects DEFINITION 54 wind damage. storm surge= ocean bulge TERM 55 Mitigating Coastal Hazards DEFINITION 55 poorly effective. work with coastal processes. planning: geologic and emergency. zoning: limit modifications in vulnerable areas TERM 56 Groundwater Flow DEFINITION 56 not like surface water. no well-defined channels. flows through the rock like an ocean. very slow compared to surface water. discharge given by darcy's law TERM 57 Porosity DEFINITION 57 percentage of a material that is open space TERM 58 Primary vs Secondary Porosity DEFINITION 58 primary= forms during deposition and lithification. secondary= develops after rock forms TERM 59 Permeability DEFINITION 59 how easily a fluid passes through a material. connected pores. if impermeable, pores are isolated. larger grains, larger pores, higher permeability TERM 60 Creating Groundwater DEFINITION 60 water soaks into ground through porous and permeable soil. eventually pores get filled (saturated) TERM 71 Saltwater Encroachment DEFINITION 71 fresh coastal groundwater floats on saline groundwater. useless if they intersect TERM 72 Karst DEFINITION 72 plateau in slovenia with lots of caves, sinkholes, etc. only forms in humid region with carbonate bedrock. TERM 73 Cave Formations DEFINITION 73 speleothems. form when co2 rich water enters open space, calcite reprecipitates. TERM 74 Thermal Features DEFINITION 74 hot springs and geysers. water is meteoric (rainfall) not juvenile (magma) TERM 75 Subtropical and Polar Deserts DEFINITION 75 descending winds. ascending winds extract precipitation TERM 76 Rainshadow and Interior Deserts DEFINITION 76 winds dry. flowing over mountains or across continents TERM 77 Coastal Deserts DEFINITION 77 dry ocean winds. cold ocean currents cool and dry overlying air then the winds blow on land and suck out the moisture. atacama is the driest place on earth TERM 78 Desert Pavement DEFINITION 78 layer of gravel on surface because winds remove all the lighter sediments TERM 79 Cliffs in the Deserts DEFINITION 79 retreat, but maintain the same shape and orientation. thick bedded rocks form cliffs. thin bedded rocks form steps. TERM 80 Moving Dunes DEFINITION 80 sand saltates up windward side of the dune, slips down the lee side. upper dunes cut off lower dunes and create cross beds TERM 81 Loess DEFINITION 81 deposits of wind blown dust. TERM 82 Alpine (valley) Glaciers DEFINITION 82 found in mountainous regions world wide. smaller TERM 83 Continental Glaciers DEFINITION 83 greenland and antartica. huge. TERM 84 Glacier Formation DEFINITION 84 snow, compact, repeat TERM 85 Glacial Budgeting DEFINITION 85 constantly flow downhill. more snow= snowline advances. less snow= snowline retreats TERM 96 Erratics DEFINITION 96 out of place rocks deposited by glaciers. igneous/metamorphic boulders on sedimentary layers TERM 97 Varves DEFINITION 97 seasonal layers deposited in meltwater lakes. silt in spring, clay in winter TERM 98 Moraines DEFINITION 98 till at the margins of the ice. names based on location (end, lateral, medial, ground) TERM 99 Drumlins DEFINITION 99 small hills of till formed from groundwater moraine. asymmetric because steeper face is towards ice source TERM 100 Eskers DEFINITION 100 sub-ice stream channels. meltwater deposits, so may be sorted and stratified TERM 101 Oxygen Isotopes DEFINITION 101 o18 and o16. warmer temps increase ratio of 18 to 16 TERM 102 Glacial Period Hypotheses DEFINITION 102 1. changes in the sun. 2. changes in the relationship of earth to the sun. 3. changes in the heat budget due to land arrangement. 4. changes in the heat budget due to atmospheric transparency. TERM 103 Reservoir vs Flux DEFINITION 103 reservoir= where matter is stored. flux= transfers between reservoirs TERM 104 Observed Changes due to Anthropogenic Fluxes DEFINITION 104 atmosphere is richer in carbon based absorptive gases, retreating glaciers, disappearing ice shelves, shrinking ice caps