chapter 9 Flashcards
Outgassing
the release of trapped gases from rocks, forced out through cracks, fissures, and volcanoes from within Earth; the terrestrial source of Earth’s water
Eustasy
change in global sea level caused by changes in the volume of water in the oceans glacio-eustatic; sea-level changes caused specifically bu glacial ice melt
what pourcentage of the water on earth is in the oceans
97.22%
what pourcentage of water is fresh
2.78%
Hydrologic cycle
a simplified model of the flow of water, ice, and water vapour from place to place. Water flows through the atmosphere and across the land, where it is stored as ice and as groundwater. Solar energy empowers the cycle
Transpiration
the movement of water vapour out through the pores in leaves in the atmosphere; the water is drawn by the plant roots from soil-moisture storage
Evapotranspiration
the merging of evaporation and transpiration water loss into one term
14% of the water entering Earth’s atmosphere
Interception
a delay in the fall of precipitation toward Earth’s surface caused by vegetation or other ground cover
Infiltration
water access to subsurface of soil moisture storage through penetration of the soil surface
Overland flow
surplus water flows across the land surface toward stream channels. Together with precipitation and subsurface flows, it constitutes the total runoff from an area
surface runoff
when soils are saturated or when the ground is impermeable
Percolation
the process by which water permeates the soil or porous rock into the surface environment (goes trought)
Soil-moisture zone
the area of water stored in soil between the ground surface and water table. Water in this zone may be available or unavailable to plant roots, depending on soil texture characteristics
what pourcentage of precipitation over land infiltrates the subsurfaces
76%
what pourcentage of this water returns to the atmosphere either by evaporation from soil or transpiration from plants
85%
Base flow
the portion of streamflow (when water go down stream, like a river) that consists of groundwater, groundwater that comes back to the surface
Water budget
measuring the input of precipitation and its distribution and the outputs of evapotranspiration, including evaporation from ground surfaces and transpiration from plants, and surface runoff, also the moisture that is stored in the soil-moisture zone. Can cover any time frame, from minutes to years
Surplus
the amount of moisture that exceeds potential evapotranspiration; moisture oversupply when soil-moisture storage is at field capacity; extra or surplus water
Deficit
the amount is unsatisfied
Precipitation
rain, snow, and hail - the moisture supply
Rain gauge
a weather instrument; a standardized device that captures and measures rainfall
Potential evapotranspiration
the amount of water that would evaporate and transpire under optimum moisture conditions when adequate precipitation and soil moisture are present, PE
Actual evapotranspiration
AE; the actual amount of evaporation and transpiration that occurs; derived in the water balance by subtracting the deficit (D) from potential evapotranspiration (PE)
Soil-moisture storage
STRGE; the retention of moisture within soil; it is a savings account that can accept deposits (soil-moisture recharge) or allow withdrawals (soil-moisture utilization) as conditions change, the volume of water in the subsurface soil-moisture zone that is accessible to plant roots
Hygroscopic water
that portion of soil moisture that is so tightly bound to each soil particle that it is unavailable to plant roots; the water, along with some bound capillary water, that is left in the soil after the wilting point is reached
Wilting point
that point in the soil-moisture balance when only hygroscopic water and some bound capillary water remain. Plants wilt and eventually die after prolonged stress from a lack of available water
Capillary water
soil moisture, most of which is accessible to plant roots; held in the soil by water’s surface tension and cohesive forces between water and soil, held in pores that are small enough to hold water against gravity, but not so tightly that roots cannot absorb it
Field capacity
water held in the soil by hydrogen bonding against the pull of gravity, remaining after water drains from the larger pore spaces; the available water for plants
Gravitational water: that portion of surplus water that percolates downward from the capillary zone, pulled by gravity to the groundwater zone
Soil-moisture utilization
the extraction of soil moisture by plants for their needs; efficiency of withdrawal decreases as the soil-moisture storage is reduced
soil-moisture recharge
water entering available soil storage spaces
Permeability
the ability of water to flow through soil or rock; a function of the texture and structure of the medium
Drought
does not have a simple water-budget definition; rather, it can occur in at least four forms: meteorological drought, agricultural drought, hydrologic drought, and socioeconomic drought
Meterological drought
degree of dryness, as compared to a regional average, and the duration of dry conditions
Agricultural drought
shortages of precipitation and soil moisture affect crop yields
Hydrological drought
effects of precipitation shortage (both rain and snow) on water supply, such as when streamflow decreases, mountain snowpack declines, etc…
Socioeconomic drought
reduced water supply causes the demand for goods or services to exceed the supply, such as when hydroelectric power production declines with reservoir depletion
where is stored the largest amount of surface freshwater on Earth
in glaciers, permafrost, and polar ice
where does the surface runoff and base flow from groundwater move across Earth’s surface
in rivers and streams
rivers and lakes
Fed by precipitation, streamflow, and groundwater, and store about 125 000 km3, or about 0.33% of the freshwater on Earth’s surface
Effects of Climate Change on Lakes
- Change in the thermal structure of a lake
- Some lake levels are rising in response to the melting of glacial ice; others fall as a result of drought and high evaporation rates
advantages and disadvantage of hydroelectric Power
Advantages; flood control, water-supply storage, power production
Disadvantage; water pollution, relocation of many people
Hydropower
electricity generated using the energy of moving water, usually flowing downhill through the turbine at a dam; also called hydroelectric power
Transfer of water over long distances in pipelines and aqueducts is especially important where
in dry regions where the most dependable water resources are far from population centres
Wetland
an area that is permanently or seasonally saturated with water and characterized by vegetation adapted to hydric soils; highly productive ecosystem with an ability to trap organic matter, nutrients, and sediment
Groundwater
water beneath the surface that is beyond the soil-root zone; a major source of potable water
what is the main source of groundwater
precipitation
what pourcentage of the world’s irrigation comes from underground water
80%
what pourcentage of the world’s drinking water comes from groundwater
50%
Zone of aeration
a zone above the water table that has air in its pore spaces and may or may not have water
Zone of saturation
a groundwater zone below the water table in which all pore spaces are filles with water, bounded at the bottom by an impermeable layer of rock that obstructs further downward movement of water 0
Water table
the upper surface of groundwater; that contact point between the zone of saturation and the zone of aeration in an unconfined aquifer
Aquifer
a body of rock that conducts groundwater in usable amounts; a permeable rock layer
Unconfined aquifer:
has an opening on top which allows the groundwater to get directly recharded by precipitation for example
Confined aquifer
bounded above and below by impermeable layers of rock or unconsolidated materials
Aquiclude
an impermeable rock layer or body of unconsolidated materials that blocks groundwater flow and forms the boundary of a confined aquifer
Potentiometric surface
a pressure level in a confined aquifer, defined by the level to which water rises in wells; causes by the fact that the water in a confined aquifer is under the pressure of its own weight also known as a piezo metric surface. This surface can extend above the surface of the land, causing water to rise above the water table in wells in confined aquifers
Artesian Water
pressurized groundwater that rises in a well or a rock structure above the local water table; may flow out onto the ground without pumping
Cone of depression
the depressed shape of the water table around a well after active pumping. The water table adjacent to the well is drawn down by the water removal, drawdown
what is a possible effect of removing water from an acquirer
the ground will lose internal support and collapse as a result
On the surface, the visible result may be land subsidence, cracks in foundations, sinkholes, and changes in surface drainage
Groundwater mining
pumping an aquifer beyond its capacity to flow and recharge; an overuse of the groundwater resource
Desalination
in a water resources context, the removal of organics, debris, and salinity from seawater through distillation or reverse osmosis to produce potable water
what happen if groundwater get polluted and how it happen
- remains polluted virtually forever
- industrial injection wells, septic tank outflows, seepages from hazardous-waste disposal sites, industrial toxic waste, agriculture residues, urban solid-waste landfills
fracking
uses an injected fluid to feature the shale
- Leaks cause build-up of methane in groundwater, leading to contaminated drinking water wells, flammable tap water, methane accumulation in buildings, and possible explosions
- google; the process of injecting liquid at high pressure into subterranean rocks, boreholes, etc. so as to force open existing fissures and extract oil or gas.
what percentage of Earth’s renewable water does Canada have
9%
Consumptive use
refers to the permanent removal of water from the immediate water environment. This water is nor returned and so is not available for a second or third use. Examples include water lost to evapotranspiration, consumed by humans or livestock, or used in manufacturing
Water withdrawal
sometimes called nonconsumptive use or offstream use, refers to the removal or diversion of water from surface of groundwater supplies followed by the subsequent return of that water to the same supply. Exemples include water use by industry, agriculture, and municipalities and in steam - electric power generation. A portion of the water withdrawn may be consumed.
Instream use
refers to uses of streamflow while it remains in the channel, without being removed. Examples include transpiration, waste dilution and removal, hydroelectric power production, fishing, recreation, and ecosystem maintenance, such as sustaining wildlife
