Environmental Science Exam 2 Week 8 Flood waters contain sewage drowned livestock pollutants Flood plains level areas adjacent to rivers Lots of floods in China US Floods 70 of disasters each year Runoff water flow when soil is full of water and there is excess water from rain River freshwater flowing towards ocean Watershed region drained by single river or river system Amazon River Watershed Stream in channel confined in bed and banks Amazon water from Andes Mountains flow east to Atlantic Ocean Covers 40 of South America 1 5 of all freshwater comes from Amazon Deltas Fan shaped deposits streams at base level Rivers deposit sediment in deltas Sediment causes branching channels Amazon no delta due to strong tidal bore Bedload coarse material moving on river bottom Suspended load fine material carried along in water column Dissolved load dissolved minerals in water Meandering Rivers low lying flat areas S shaped curves contain large floodplains Worlds Muddiest river Chinas Haung Ho Yellow River Great 1993 Mississippi and Missouri River Floods 2008 Great Midwest flood Levee failure in Illinois 2009 Red River Flood lack of slope becomes shallow lake flat lake plain Hydrograph graph of river s discharge or stage height vs time Discharge Q W x D x V volume of water flowing past point of river in certain amount Floodplain flat surface adjacent to river channel Flood stage overtopping of banks by water Flood crest highest level above flood stage river reaches during flood of time D height or stage W width V velocity Flash floods Riverine Floods larger volumes of water than flash floods rainstorms and spring runoff from melting snow Delaware River Flooding April 2005 major snow cover in Pocono and Catskill mountains and heavy spring rains Flood forecasting past events ranking them future possibilities Recurrence Interval average time between floods of a given size return time Artificial leeves clay sand soil Flood walls concrete Channelization straightening deepening widening clearing Hurricane Floyd 1999 costliest disaster in NJ history Dams hydroelectric power irrigation flood control creation of lakes drinking water Three Gorges Dam worlds largest hydroelectric dam 1 What is a river and its floodplain River body of flowing water Floodplain Level area adjacent to river 2 What part of the water cycle is runoff Water flow when soil is full and there is excess water from rain end then evaporates 3 What is a watershed Drainage basin 4 What is a hydrograph What is the definition of stage Hydrograph graph of rivers discharge Stage Hieght vs time 5 What is the 100 year flood What data is used in graphing a recurrence interval for a specific river 1 probability of occurring in any given year Hydrographs flood recurrence interval 6 How affects does urbanization have on flooding of impervious cover roofs cement asphalt of area served by storm sewers Alters natural surface runoff patterns Increases size and frequency of floods Less water goes into ground more runoff Reduces lag time amount 7 What are some basic flood prevention methods levees flood walls storm retention basins channelization What are some pros and cons with them Leeves clay sand soil Flood walls concrete Storm retention basins holds water until flood subsides Channelization straightening deepening widening 8 How does land use affect flooding Eliminates habitats and vegetation 9 How do we assign flood insurance Producing flood hazard maps which satisfies minimum standards of land use regulation within 100 year flood plain 10 Why are dams constructed What are some adverse environmental effects from dams hydroelectric power irrigation flood control creation of lakes drinking water loss of land habitat destruction change in water quality flow reduction and disease 11 What is a drought Where do they usually occur No water deserts Week 8 Water Resources Hydrosphere 97 2 is ocean 2 8 is freshwater Colorado River used for water supply among 7 states Infiltration water soaks into ground 100 gallons per person per day Increased water demand irrigation requirements to meet energy development States fought over legal entitlements Dams water storage and power generation have tamed river Los angeles water shortages Groundwater water beneath earth s surface water beneath water table in zone of saturation water filling pre space in soil and rock Water table Spring water table intersects ground surface ground water discharge Porosity portion of material that contains open spaces Permeability connection between pore spaces Aquifer rock brings water to wells and springs high porosity and high permeability sand Confining bed impermeable rock that doesn t transmit water freely clay igneous sedimentary metamorphic rock Confined aquifers below and above confining beds internal pressure Artesian water rises above level in aquifer Potentiometric surface elevation water in well Over pumping effects Pumping too much water lowers water tables Pulling salt water into fresh water aquifers Desalinization Subsidence sinking settling lowering parts of the crust of the earth High Plains Aquifier groundwater mining water gulping corn lowered water tables 1 What is Infiltration Water soaks in ground 2 What is the definition of groundwater Water beneath earth surface 3 What are some characteristics of the water table What is a spring Spring water table intersects land 4 What is porosity permeability Porosity open spaces Permeability connection between pore spaces 5 What is the definition of an aquifer confining bed What are the basic characteristics of each What are some examples of each rock types Aquifier rock brings water to well and streams porosity permeability sand Confining bed all rock types not porosity or permeability 6 What is the difference between a water table and a confined aquifer Water table Confined aquifer below and above confining bed 7 Understand some of the basic effects of overpumping including groundwater mining High Plains or Ogallala Aquifer saltwater intrusion and desalinization and subsidence Overpumping lowers tables Desalinization salt water combines with fresh hard to remove Subsidence sinking parts of earth 8 Case Study Colorado river and surface water Los Angeles water supply Colorado River irrigation hydropower states fighting over legal entitlements river got shallow Los Angles desert area little water water shortage Week 9 1 What is water potable water hard water How do you treat for hard water Water dipolar molecule Potable