DOC PREVIEW
UConn GEOG 2300 - Exam 3 Study Guide

This preview shows page 1-2-3-4 out of 13 pages.

Save
View full document
View full document
Premium Document
Do you want full access? Go Premium and unlock all 13 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 13 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 13 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 13 pages.
Access to all documents
Download any document
Ad free experience
Premium Document
Do you want full access? Go Premium and unlock all 13 pages.
Access to all documents
Download any document
Ad free experience

Unformatted text preview:

GEOG 2300 1st EditionExam # 3 Study Guide Lectures: 26 - 36HydrologyLecture 26 (April 1)I. Surface WaterA. In streams, velocity of flow is greatest in the middle and at the topB. Stream slope is steep in rapids and gentle in poolsC. Stream cross-sectional area is small in steep sections and large in poolsD. Stream discharge is constant for any given section of stream with no inputs oroutputsE. Discharge (Q) can be calculated as the cross-sectional area times the stream velocityF. Maximum load of sediment that a river can carry with a given discharge=stream capacityG. Hydrograph: a plot showing the variation in the discharge of a stream over timeH. The lag time between peak discharge and peak precipitation reflects the timerequired for water to move down slopes and through progressively larger stream channelsII. River SystemsA. Consist of a trunk joined by tributariesB. The complete system forms a drainage basin (watershed)C. The pattern of the rivers-drainage network (dendritic, trellis, . . . )III. FloodsA. When a stream overflows its channelB. Low-lying ground next to the river (floodplain) is said to be inundatedLecture 27 (April 6) IV. Monitoring DischargeA. The discharge of a stream is a combination of base flow and surface flowB. Base flow: steady, year-round flow from groundwater into the streamC. Surface flow: occurs during storms when the infiltration capacity is exceeded on hill-slopes and extensive overland flow reaches the streamsD. Surface flows occur much more rapidly and create larger peaks in the hydrographE. Reducing infiltration capacity leads to larger, and more frequent, flood eventsF. Flood events  more pollutionG. Flood waves appear as peaks in hydrographH. Because discharge is proportional to cross-sectional are, rivers in flood will bedeeper and overflow banksI. Large floods occur rarely because the right combination of precipitation that leads to them occurs rarelyJ. If all discharges are plotted against the probability that they will occur, the likelihood of a flood of a given magnitude occurring can be determined, ex: 50 year flood, 100 year flood (assuming conditions within the river basin don’t change) K. Red River Flood (1997): numerous snow storms (including one in April), saturated soils, flat terrain, large catchment, decimated Fargo and Grand ForksV. LakesA. Lake: receives input from streams, overland flow, and groundwaterB. Lakes lose water from outlets and by evaporationC. Lakes tend to be short lived on a geologic timescale (filled in by sediment andvegetation or dry out as outlet streams erode over 100’s-1000’s of years)D. In moist climates, the water level of a lake coincides with the level of the groundwater tableVI. Saline LakesA. Saline lakes: characteristic of arid areas (evaporation leaves salts behind)B. Saline lake basins have no outlet and therefore water leaves through evaporation (endorheic basin)C. Excessive evaporation creates salt flatsVII. GroundwaterA. Precipitation absorbed by soil (infiltration)B. If soil is saturated, or precipitation is too rapid-runoff (leading to overland flow)C. Saturated zone: Subsurface water saturating bedrockD. Water table is highest under hills (seepage into streams lowers it in valleys)E. Springs emerge where water emerges from the groundF. Aquifer: porous rock saturated with groundwaterG. Aquicludes: other layers of impermeable rocks keep that water inH. Unconfined aquifer: when permeable sediments lie between the water table and the surfaceI. Confined aquifer: if impervious rock caps the aquifer such that the pressure in the aquifer is higher than it would be without the impervious rockJ. Artesian well: a well dug into a confined aquifer K. Flowing artesian well: if the pressure in the confined aquifer is great enough that water flows out of the wellL. When water is removed from an aquifer by a well, it pulls down the water table near the well, forming cone of depressionM. The amount by which the water level is reduced from the original water tablelevel is called the aquifer drawdownLecture 28 (April 8)VIII. AquifersA. Pollutants enter the groundwater from landfills, leaking oil tanks, surface pollutants infiltrating, etcB. Once in the aquifer, pollutants flow with the hydrologic gradient toward a well or streamIX. Water ProblemsA. Too little water  droughts  overdrawing surface waters  aquifer depletion  can lead to subsidence and saltwater intrusionB. Ogallala aquifer depletion under the Great PlainsC. Pivot irrigation is more efficient and easier, the water is rotated around the field, makes a circleX. Withdrawing GroundwaterA. Pros of groundwater: useful for drinking and irrigation, available year round, exists almost everywhere, renewable if not over-pumped or contaminated, no evaporation lossesB. Cons of groundwater: aquifer depletion from over-pumping, sinking of land (subsidence) from over-pumping, polluted aquifers for decades or centuries, reduced water flow into surface watersC. Prevention: waste less water, raise price of water to discourage waste, subsidize water conservation, ban new wells in aquifers near the surface watersXI. DeforestationA. Leaf litter improves soil fertilityB. Tree roots stabilize soil and aid water flowC. Vegetation releases water slowly and reduces floodingD. Loss of vegetation: gullies and landslides, rapid runoff and flooding, wind will remove fragile topsoilE. Urbanization: increases potential for flooding on flood plains, increases transport of pollutants into waterways, reduces water recharging aquifers, increases urban heat island effectF. Flood management: channelization and levees (used in New Orleans), setback levees are better at flood management because they allow for wider rivers, but they would require towns, cities and homes to move in order to build them, so some rivers are just channelizedG. Prevention of flood damage: preserve forests on watersheds, preserve and restore wetlands in floodplains, tax all development on floodplains, strengthen and deepen streamsH. Dams: provides water for year round irrigation of cropland, provide drinking water, recreation, hydropower, downstream flooding reduced, but flooded land, large water losses from evaporation, downstream land deprived of nutrient rich soil, some fish spawning disruptedLecture 29 (April 10)XII. Water Use A. Most water use is used for toilet flushing and bathingB. Very dry conditions in southern California, but wet conditions along western side of Sierra


View Full Document

UConn GEOG 2300 - Exam 3 Study Guide

Download Exam 3 Study Guide
Our administrator received your request to download this document. We will send you the file to your email shortly.
Loading Unlocking...
Login

Join to view Exam 3 Study Guide and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Exam 3 Study Guide 2 2 and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?