Define an arid area two key characteristics -Potential Evapotranspiration exceeds Precipitation for a significant portion of the year resulting in a large negative water balance in soil moisture budget. - Less than 250 mm of precipitation per year List three causes of deserts. - High pressure / Anticyclone dominates (i.e. 30N and S) High = Dry - Rainshadow / leeward side of mountains - Continental interior - Nearby cold ocean current - Offshore wind -On the descending branch of a convection current / hadley cell Name three of the numbered deserts shown. P.179 in textbook. Distinguish between aridity and infertility using an example we have seen and discussed. Sahara = arid but soil is fertile due to mineral content however one needs a large amount of irrigation water to make agriculture possible The gradual lowering of the desert floor due to wind erosion is called __________________. deflation Name and explain a water feature that can result from deflation. Deflation may expose the water table to produce an oasis. The gradual lowering of the desert floor due to wind erosion is called __________________. deflation With this process, a pebble-strewn desert pavement may be left behind called ____________________. reg If only the hard rock pavement is left it is referred to as ____________________. hammada List and describe three processes of wind transport. barchan N Prevailing wind?Northwest ?? windwardleeward erg p.185 What term is used to describe wind related processes in the desert? Eolian or aeolian What US City did Celine Dion perform in exclusively for several years? What is the main source of this citys drinking water? Las VegasLas Vegas, Lake Mead on Colorado river What is happening to the Colorado rivers delta and why? Turning into a mudflat as most years, the Colorado river does not reach the Gulf of California as its water is diverted and used up. As well, lower snowpack in the mountains is putting less water into the drainage system. What % of the western United States water supply is derived from snowpack? 75% Due to drought (2012 to 2014) and the resultant reduction in available water from rivers like the San Joaquin and Sacramento, list three ways in which farmers in California are coping? Letting part of their fields go fallow, using drip irrigation derived from groundwater, growing crops that require less water eg prickly pear cactus fruit Due to drought and diminishing water supplies, the city of San Diego is spending how much to upgrade a sewage treatment plant to recycle wastewater to drinking water quality? $2.5 billion Up until recently, Californias regulation of groundwater extraction has been described as the weakest in the nation. Why? in most cases California landowners can still drill water wells as often and as deeply as they can afford, without permission from government agencies or neighbors. With few exceptions, users are not required to report how much they pump, and public access to drilling records is highly restricted. What have been two environmental impacts of chronic over pumping of groundwater? Widespread land subsidence in parts of the Central Valley; more than 30 feet (9 m) over recent decades in some places. Groundwater-fed surface streams depleted threatening species depending upon them. New laws come into effect in California for the management of groundwater in Jan that will give local agencies the power to restrict groundwater pumping, shut down wells, and impose fines and penalties on resistant landowners. What are some concerns though about the effectiveness of these new regulations? The new laws give local agencies five to seven years to develop those groundwater plans, and until 2040 to implement them. A clause also prohibits public disclosure of personal information related to groundwater extraction, a caveat that he could be broadened to keep basic pumping data under wraps. And while the laws do bring California's groundwater management goals roughly in line with those of other western states, the West's policies still lag behind Australia's, where groundwater management plans must reserve water for the environment. Rivers such as the Colorado and Nile which originate in mountains beyond the desert margins are called _____________________ rivers. exotic or exogenous The Nile has what type of delta? arcuate Alluvial fan Playa lake Volcanic neck or plug Talus or scree Fluvial or aeolian generated?fluvial Erosion or deposition?erosion ___________________: are extensive ridges of rock, separated by grooves (troughs), with an alignment similar to the prevailing winds; they are parallel ridges of hard rock up to 15 m (50 ft.) high. They form when alternating hard and soft rock layers are upended. Yardangs Fluvial or Aeolian? & Deposition or Erosion? Aeolian and Erosion abrasion How do these zeugens differ from yardangs? Tabular masses of resistant rock separated by trenches where the wind has cut vertically through the cap into underlying soft rock. Strata are horizontal. Specific Type of Weathering and describe? exfoliation Salt shattering wadi Why are deserts vulnerable to flash floods? Offer three reasons. -Infrequent but intense storms; may originate far away in mts.; water carried in canyons and wadis -Very dry ground has difficulty absorbing water initially = enhancing surface runoff - Lack of vegetation = lack of interception = enhanced surface runoff -Rain-splash erosion displaces fine particles which in turn seal off the surface and make it impermeable Flash floods help to produce what category of streams / rivers? Ephemeral _____________: shallow slopes formed at the base of a cliff or steep hill. Pediment bajada Star Dunes how formed? Wind blows from several directions over time. To within + or 5%, what % of water usage in the Okanagan Valley goes towards agriculture? 70% List two specific means to help conserve water in agriculture. Trickle Drip Irrigation and irrometers (soil moisture meters) to better time water release. Name two ways of promoting conservation for domestic water usage. -Water meters in homes How much money is the Egyptian government planning to invest over the next decade to reclaim nearly 1.5 million hectares of desert for agriculture? $70 billion Which group is being targeted to participate and what is an incentive? College graduates, cheap desert land Which country has no formal allocation of Nile water, but depends heavily upon it for its own agriculture? Ethiopia Supporters of the project say farming in the Sahara is economically viable because of.? -Proximity to European markets -lack of pests which are more common in humid climates Opponents of the project would rather see what happen? Ecotourism eg $400 per night in an ecolodge All of Israels irrigated areas use drip irrigation which has reduced their water consumption per unit of land by _______? 50-70% To ensure its water supply, what else has Israel incorporated? Built 30 desalinization plants which removes salt from brackish water. Outline the main causes of desertification. -Fuelwood collection -Overgrazing -Overcultivation -Overpopulation -Climate Change Which biome is most vulnerable to desertification? Grasslands (either Tropical Grasslands / Savannah or Temperate Grasslands) What is the name given to the region of Africa that is very vulnerable to drought and desertification? A transition area between the Sahara and the African Savannah. To adapt to their environment, many Tuareg groups follow a transhumance pattern. What is this? Movement from a dry-season home area to a summer- season pasture area; move herds to the Azawagh Valley from July to Sept. to take advantage of abundant vegetation there to feed their flocks during the rainy season; manage camel herds to give birth during this time; main source of drinking water during this time = from collection ponds; rest of year depend on groundwater wells from aquifers. How is uranium mining in Niger a problem for the Tuaregs? Identify three things. -Depletion of groundwater supplies threatening the Tuaregs ability to survive the nine month dry season -Water and land is being polluted by uranium mining putting people and animals increasingly at risk for illness, cancer, stillbirths, and genetic defects - Disruption to land surface increases risk of desertification -Exclusion from mining jobs and profits How is tourism a factor leading to desertification in Crete? -Increasing urbanization + visitors = large water requirements -Drill more wells into aquifers = lower water table = drying out of land Examples of how water is being wasted in the city of Heraklion? -Old and leaky water network = 50% of water being lost - Lack of tertiary sewage treatment = tons of water flushed into the sea daily instead of being re-used for irrigation How is agriculture leading to desertification in Crete? - Over-intensive use of the land, over-pumping of ground water, irrigation with water with a high mineral salt content (i.e. salinization), use of acidic chemical fertilizers and destruction of vegetation - Overgrazing by thousands of sheep and goats + fires set by shepherds to burn off dry grasses and encourage the growth of fresh grass intensifies the problems of desertification and soil erosion Olive Plantations The Gobi desert has been spreading at a rate of ______ per year resulting in more frequent _____________ for Beijing. sandstorms 2.4% How is Beijing adapting to this? Use of satellites, radar, sounding balloons and other meteorological technologies to form a real-time network to identify the areas sandstorms will sweep over i.e. better forecasts to warn people. Discuss a scenario whereby a glacier will advance. Rate of accumulation exceeds the rate of ablation. For each of the following slides, identify each feature and state whether it is primarily an erosional or depositional feature. Hanging valley - erosional Medial Moraine - depositional Finger Lake or Ribbon Lake depositional i.e. terminal moraine acts as a dam blocking the meltwater Arte knife edged ridge between two cirques - erosional Tarn - erosional Drumlin - depositional Terminal moraine - depositional Moraines are made up of what material? Till Truncated Spur - erosional Name three processes which aid in the formation of the truncated spur. Freeze Thaw Action, Plucking, and Abrasion Describe the key climate characteristics of the Arctic Tundra Periglacial Environment and explain why they exist. -Very dry; below 250 mm in avg. annual precip. high pressure dominates (due to extreme cold ) -Avg. annual temp. below -5C for areas of continuous permafrost (within the Arctic Circle - 66.5N); average annual temp. between -1C and -5C for areas of discontinuous permafrost lack of solar insolation + high albedo effect due to snow - Growing season in the Arctic = less than two months What is this periglacial landform? There are over 1400 of them in the Mackenzie Delta. Closedsystem (hydrostatic) Pingo: -Occur in flat, low- lying areas - Continuous permafrost - Often form on sites of small lakes where water is trapped by freezing from above and by the advance of the permafrost from the lake margins. - As the water freezes it will expand, forcing the ground above it to rise upwards into a dome shape. Talik = unfrozen ground What is thermokarst? - the subsidence of the land caused by the melting of permafrost - depth of the active layer increases - irregular, hummocky terrain results with marshy or lake-filled hollows Explain two human activities that can increase the presence of thermoskarst (i.e. the level of the permafrost table is lowered)? -Removal of tundra vegetation for construction exposes the ground to summer heat more easily -Construction of centrally heated buildings warms the ground - siting of oil, sewerage, or water pipes in the active layer increases the rate of thaw -Drilling for oil and gas = warm drilling fluids = melts permafrost Describe three methods to reduce problems created by the development of periglacial areas. In areas of repeated freezing and thawing, frost heave both lifts and sorts materials to form _______________________ _. patterned ground In 2007, the exploration and mining sector spent $230 million in Nunavut. What minerals hold tremendous potential? - iron, gold, diamonds, copper, nickel, (possibly uranium) Other than increased thermokarst, what are other concerns regarding the expansion of mining in Nunavut? - Impact on caribou, sea mammals (eg narwhals) and fish It has been estimated that the entire Arctic may hold around _____% of the worlds untapped oil and gas reserves. 20 Which countries are making territorial claims in the Arctic Ocean? Canada, United States, Russia, Norway, and Denmark How much have average temperatures in the Mackenzie basin risen in the past 50 years? 2C How is Tuktoyaktuk being impacted by climate change? -Coastline has eroded 100m since Thinner ice pack on the Arctic ocean and longer freeze up time in the Fall makes it more vulnerable to erosion from storms + affecting their ability to hunt and fish on ice shelves The Northwest Passage reduces ship travel time between Europe and Asia by how much? Two weeks 7000 km saving Type of mass movement in the periglacial environment resulting in visible lobes in the foreground? The Jordan river which empties into the Dead Sea is an example of what type of river in a hot, arid environment? Type of mass movement in the periglacial environment resulting in visible lobes in the foreground? Solifluction The Jordan river which empties into the Dead Sea is an example of what type of river in a hot, arid environment? Endoreic