Recurrence Interval return period is the average time period within which a given event will be equaled or exceeded once Lab Final Review Lab 15 Recurrence Intervals for Natural Events 1 Steam Flow 2 Forest Fires 3 Other natural hazards RI n 1 m RI recurrence interval in years N number of years on record of years M Rank of flood Flood Water that overflows the natural riverbanks Hydrology Science of Water ex surface and groundwater Discharge stream volume of flow per unit of time Gage height stream depth above stage referred to as the flood stage Flood Frequency Curve A curve that shows the mathematical relationship between flood peak flows flood peak water levels or flood volumes at a particular location and the annual exceedance probability of that quantity Flood probability the probability of a flood of a given size being equaled or exceeded in a given period a probability of 1 percent would be a 100 yr flood a probability of 10 percent would be a 10 yr flood Rating Curve a drawn curve showing the relation between gage height and discharge of a stream at a given gagging station Stream flow volume of water carried by a stream Discharge formula Q WDV W river channel width D channel depth V stream velocity Expressed as cubic meters Discharge ft 3 sec Gage height feet Higher return Interval more catastrophic lower probability Problems Floodplain development Channelization Lab GPS Global Positioning Systems Global positioning systems are comprised of two components that used together to determine location A network of 24 satellites operated and developed by the US department of defense that orbit the Earth twice a day and can define there position by altitude and orbital path Receivers that are land based sold commercially and can range in size and price depending on level accuracy Calculating slope distance ft mi 2 Developed by US department of defense Network of 24 satellites A receiver Must have at least 3 satellites to pick you up for position Triangulation 2 known angles and 3rd angle can be determined Trialteration 2 known side lengths and 3rd length can be determined More satellites more accurate Latitude measure distance from equator North South Longitude measure distance from Prime Meridian East West Tuscaloosa Coordinates Lat 33 degrees North Long 87 degrees West If you walk north latitude will increase and if you walk west longitude will increase Satellite screen shows the position and name of satellites currently being tracked Map Screen shows you a map of where you are with respect to other map features Navigation Page displays current position in selected coordinates as well as your speed and direction elevation and current time Altimeter page tells you your speed and direction Main Menu is where you go to mark and manage waypoints and routes and makes changes in the configuration of your gps Lab 11 Fluvial Geomorphology Denudation General term referring to all processes that cause reduction and rearrangement of landforms It affects surface materials like weathering mass movement erosion transportation and deposition as it is produced by agents of moving water air waves ice and the pull of gravity Fluvial Geo Is the science that analyzes river line landforms Steam Channel Water and sediment movement process determine the dimensions of all rivers Erosion displacement transportation of earth material Deposition the setting and accumulating of transported earth material Alluvium general term for clay slit Back swamp is the section of a floodplain where deposits of fine silts and clays settle after a flood Drainage basins is the spatial geomorphic unit occupied by a river system defined by ridges that form these drainage dividers Drainage patterns arrangement of channels determined by slope differing rock resistance climatic and hydrologic variability Watershed the catchment area of a drainage basin River types Meandering channel oxbow lakes and meandering scars Floodplain Low lying areas near a stream channel that is subjected to a recurrent flow Natural Levees By product of flooding from alluvium drops when river breaches channel walls Folded Landscapes Anti cline Ridge upfold Syncline Valley downfold Water gap River cuts through and anticlinal ridge Wind gap Once water gap occupied by stream that has been diverted by watershed Lab 12 Glacial Geomorphology Glacier large mass of ice resting on land or floating on an ice shelf in the sea adjacent to land 3 Types of Glaciers Alpine Mountain ranges Continental Massive ice over large land area Ice sheet Antarctica Greenland Ice cap Iceland Ice field Patagonia Valley an ice mass constricted within a valley that was originally formed by stream action 1 Eroisional Landform Ar te ah rate knife shaped ridge formed by glaciers on 2 sides Horn 3 sided peak shaped by glaciers on all sides Cirque bowl shaped depression at the head of a glacial valley tear drop shape Glacial Trough U shaped valley carved by a glacier Hanging Valley Small tributary glacier valley joins larger valley waterfalls are frequently present 2 Depositional Landforms Moraine moving through valley carrying debris along with it Ex Lateral debris on edge Medial 2 lateral moraines together Terminal farthest extend of glaciers End glacier ends at this moment Flat gently sloping plain of sand and debris Outwash Deposited from glacial melt water Located beyond terminal moraine Glacial Tilt Poorly sorted mixture of different sized rocks Tilt Plain Plains low relief Deranged drainage pattern After a glacier has retreated the landscapes distributed surface Rock that deviate from she and type of rock native of the area in which 3 Glacial Eratic they rest in 3 Steps Distance o Measure o Multiple by the scale o Convert Relief Slope o Highest elevation lowest elevation o rise run rise over run o rise relief in feet run distance in miles o feet per miles and meters per kilometer Example rise run 20m 5km Percent Grade Relief in feet distance in feet x100 Ex 200 10560 x 100 0 189x100 18 9 Ablation The removal of snow and ice by melting or evaporation typically from a glacier or iceberg Drumlin a low oval mound or small hill typically one of a group consisting of compacted glacial till shaped by past glacial action Esker A long ridge of gravel and other sediment typically having a winding course deposited by melt water from a retreating glacier or ice sheet Tarn a small mountain lake Kame a steep sided mound of sand and gravel deposited by a melting ice sheet