Planet Earth Exam 3

What is Osmosis?

"In order to visualize this effect, imagine a U-shaped tube with equal amounts of water on each side, separated by a water-permeable membrane made from dialysis tubing at its base that is impermeable to sugar molecules. Sugar has been added to the water on one side. The height of the liquid column on that side will then rise (and that on the other side will drop) proportional to the pressure of the two solutions due to movement of the pure water from the compartment without sugar into the compartment containing the sugar water. This process will stop once the pressures of the water and sugar water on both sides of the membrane become equal (see osmosis)."

Climate Has Always Changed, What's the Big Deal Now?

"Indeed, natural changes have happened, with continental drift altering atmospheric CO2 over tens of millions of years, wiggles in the orbit causing ice ages and CO2 changes over tens of thousands of years, and other natural changes. Earth and life are still here. If we didn't have a special concern for humans, and for the other species that we know, climate change might not be a big deal."Richard Alley "Shown here is the history of three trace gases that warm the planet (carbon dioxide or CO2, nitrous oxide and methane) over the last [two] thousand years, [...] from the IPCC WG1 Third Assessment Report in 2003. Further back in time, natural changes have occurred in these, and in the climate, but the recent changes are mostly due to us. Water vapor is not shown, although it is an important greenhouse gas. Water vapor put into the air rains or snows out quickly, in just over a week on average, so we cannot put it up fast enough to make much difference. The only way we know to change water vapor a lot is to change the temperature, because warmer air picks up more water vapor from the ocean."Richard Alley

Why does CO2 reach anannual high level in May and low level in October?

"The Keeling Curve shows a cyclic variation of about 5 parts per million in each year corresponding to the seasonal change in uptake of CO2 by the world's land vegetation. Most of this vegetation is in the Northern Hemisphere, since this is where most of the land is located. From a maximum in May, the level decreases during the northern spring and summer as new plant growth takes carbon dioxide out of the atmosphere through photosynthesis. After reaching a minimum in September, the level rise again in the Northern fall and winter as plants and leaves die off and decay, releasing the gas back into the atmosphere. Carbon dioxide concentration in increasing. The last reading was 403.50 on March 8, 2016. In the 1960's it was ~320

Why Are We Responsible for the Recent Changes in CO2?

"The human cause of rising CO2 is very clear—we know from oil-tanker shipments and coal trains how much fossil fuel is being burned, burning uses oxygen and the drop in atmospheric oxygen is of the size expected to explain the burning (but with plenty of oxygen left to breathe), and other isotopic indicators agree that we are responsible for the rising CO2. The warming effect of CO2 has been known for over a century, and was clarified especially well by military research linked to World War II."Richard Alley "The bottom of this figure shows the recent rise in CO2. If the CO2 comes from burning, rather than from volcanoes or the ocean, then O2 in the atmosphere should be dropping to supply the O2 in the CO2. The upper panel shows the dropping oxygen."Richard Alley

Corpus Christi, TX; December 15, 2016

"Wednesday's advisory applies to more than 300,000 people in Corpus Christi on the Gulf of Mexico coast." "Boiling, freezing, filtering, adding chlorine or other disinfectants, or letting the water stand will not make the water safe, officials say." BBC, FoxNews "The contaminants have not yet been named, but are petroleum-based." BBC "Officials believe the contamination was caused by a faulty valve in the city's industrial district, which caused a "back-flow incident", leaking contaminants into the drinking water supply." BBC "City crews have worked to reconfigure some water mains to ensure that water keeps circulating and to prevent bacteria growth. But an overarching concern is an old water system where more than half of 225 miles of cast-iron pipe needs to be upgraded. Many of the pipes were installed in the 1950s and when they decay they're prone to collapse or to slow water flow, allowing bacteria to fester." FoxNews Other cities: Lead in water at Flint MI, Elk River chemical sptill at Charleston WV, etc.

meteorological droughts

(deficit in precipitation)

agricultural droughts

(deficit in soil moisture)

socio-economic droughts

(higher demand than the available supply)

Concluding thoughts on desalination

1. Service, Desalination Freshens Up, Science2006: Costs in Israel are now 0.527 cent/m3and in California a consortium used 1.58 kWh/m3which "At that rate, a seawater desalination plant could supply a typical U.S. household with fresh water for the amount of power needed to light an 80-watt light bulb." And this is the same amount of energy required to pump water around the state. (Note, I believe these are operating costs, but not the costs to build the desalination facility.) 2. Ghaffour Missimer, and Amy, Desalination 2013 "...the authors join the expectation of many desalination experts that the desalinated water cost will not reduce further at the same rate of decline for several reasons. The primary reasons are the instable prices of crude oil (affects energy costs), currency fluctuations, and increases in membrane prices." 3. Shannon et al., Nature 2008"supplying even 50 litres a day per capita of drinking water at 0.25kWh can be a small fraction of the daily energy required per capita (ranging from 3.2kWh in China to 30kWh in the USA)." 4. Elimelech and Phillip, Science 2011"The energy demand for seawater desalination by state-of-the-art reverse osmosis is within a factor of 2 of the theoretical minimum energy for desalination, and is only 25% higher than the practical minimum energy for desalination for an ideal reverse osmosis stage. Yet, the overall energy consumption of new SWRO plants is three to four times higher than the theoretical minimum energy due to the need for extensive pretreatment and post-treatment steps. Because thermodynamics set the limit on the energy demand for the desalination step, we argue that future research to improve the energy efficiency of desalination should focus on the pretreatment and post-treatment stages of the SWRO plant."

From 2005 to 2009, the area weighted, average water level decline was ___ feet. This represents a loss of ___ acre feet. These are annual losses of ___ ft/yr, ___ acre-ft/yr, and ___ cubic-km/yr.

1.0 - 18.3M (23 cubic km) - 0.25 - 4.6M - 5.8

From 1995 to 2000, the area weighted, average water level decline was ___ feet. This represents a loss of ___ acre feet. These are annual losses of ___ ft/yr, ___ acre-ft/yr, and ___ cubic-km/yr.

1.3 - 23.5M (29 cubic km) - 0.26 -- 4.7M- 5.8

Earths Water: Surface water / ground water

1.5 suface 98.5 ground

From 1980 to 1995, the area weighted, average water level decline was ___ feet. This represents a loss of ____ acre feet . These are annual losses of ___ ft/yr, ___ acre-ft/yr, and ___ cubic-km/yr.

2.0 - 36.0M - (44 cubic km) - 0.13 2.4M - 2.9

From 2000 to 2005, the area weighted, average water level decline was ___ feet. This represents a loss of ___ acre feet. These are annual losses of ___ ft/yr, ___ acre-ft/yr, and ___ cubic-km/yr.

2.8 - 46.7M (58 cubic km). - 0.56 - 9.34M - 11.6

The hydrological cycle ~_____ km3 cycled annually

380,000

The atmosphere around a normal classroom globe would be about

5 sheets of paper

Why is the Balbina Reservoir an "ecological disaster"?

5 turbines each require 267 m3/s flow to operate and produce electricity, but river flow capacity is only 450 m3/s. Thus there is either an excess of turbines or an inadequate supply of water for the built electrical demands. Reservoir waters cover 2400 km2, yet the vegetation was not removed prior to flooding, which initiated in 1987. As the vegetation rotted, acidic waters were produced, along with anoxic conditions that corrode turbines. Provides water surface area for CO2 and methane production and evasion into the atmosphere.

Earths Water: frozen fresh water (ice caps / glaciers) / unfrozen fresh water

74% frozen 26% unfrozen

How many people do not have access to clean water?

783 million people do not have access to clean water (and 2.5 billion do not have access to clean sanitation).

Earths Water: Salt (oceans) / Fresh

97.5 salt 2.5 fresh

Tigris and Euphrates Disputes

98.5% water in Euphrates from Turkey Syria totally dependent Iraq heavily dependent As long as there has been civilization, water available to Upsetting the Status Quo 1977 Turkey launched Southeastern Anatolia Project (GAP) 22 dams 19 hydroelectric power plants -Tigris and Euphrates systems Irrigation will use 27% of total flow (25 km3)•Tensions raised by unilateral development of basins Currently about 40% of project complete Turkey sees itself as a good neighbor -no mistaking that GAP important -water is Turkish resource, like oil Iraq Project effectively controls both rivers-political leash on Syria Turkey now has military and economic strength to be the "power broker" Root of Water Problem Volume of inflow to lake reduced from at least 50 km3 of fresh water to near zero In 40 years the lake has lost most of its water volume As part of former USSR, Moscow ordained plan for cotton; cotton today is ¼ of Uzbekistan's GDP During the winter, upstream Kyrgyzstan needs flowing water to produce hydroelectricity whereas downstream Uzbekistan needs to store water to later irrigate cotton fields. Exposure of large areas of lake bed; winds blowing over this area causes dust storms and moves salt crystals onto farmland; also respiratory problems due to dust By 1977, fish harvest reduced by 75% as freshwater fish died off; evaporation caused salinity to increase substantially; by 1980's commercial fishing industry was dead; Main port Muynak is 150 km from Aral Sea Unintended Consequences Collapse of fishing threw local economies into chaos Major health impact to region -combination of poverty, poor nutrition -contamination from agricultural chemicals 20 million people increased rates of throat and lung cancers, kidney disease, hepatitis, asthma, birth defects, TB -TB rates 250 to 370 out of every 100,000 people

What is Desalination?

A method of removing salts from sea water or from brines withdrawn from groundwater wells to produce potable (i.e., drinkable) freshwater. Gulf countries use thermal desalination to heat sea water and the evaporated water is then condensed to make fresh water. These plants consume large amounts of thermal and electrical energy and produce greenhouse gases. Outside of Gulf countries, everywhere else uses reverse osmosis, which uses much less energy than thermal methods." Elimelech and Phillip, Science 2011

A Brief History of Desalination

A. In 1966, Glueckauf wrote in Naturethat "U.S. government funding has accelerated 50 years of desalination development into just a decade." B. In 2006, Service wrote in Sciencethat "Continued improvements are expected in membranes, given that the membranes have remained little changed in 40 years." C. In 2008, Shannon et al., wrote in Naturethat "Reverse Osmosis has advanced significantly in the past decade, particularly owing to the development of more robust membranes and very efficient energy recovery systems." The amount of energy required per unit of potable water was 10 kWh/m3 in the 1980s to below 4 kWh/m3 in 2008. The authors suggest that this 2008 value could be further halved because systems have not yet reached their theoretical chemical and physical limits. D. In 2008, Shannon et al. wrote in Naturethat "Through continual improvements, particularly in the last decade, desalination technologies can be used reliably to desalinate sea water as well as brackish waters from saline aquifers and rivers." E. In 2011, Elimelech and Phillip wrote in Sciencethat "The first commercially viable membrane with the ability to effect such a separation was an asymmetric cellulose acetate membrane developed in the early 1960s. Membranes of this type were the best available technology until the 1980s when robust thin-film composite membranes were developed." F. In 2013, Ghaffour, Missimer, and Amy wrote in Desalinationthat "The recovery ratio for normal seawater desalination (35,000 mg/L of salinity) was about 25% in 1980s and it increased to 35% in 1990s. Currently, it is about 45% and can reach 60% if second stage is applied." Recovery ratio is the amount of freshwater gained compared to the amount of salt water put into the system, i.e., 50% implies that for every gallon of salt water put in, half a gallon comes out as fresh water.

Solutions for desalination

A.In 1966, Glueckauf wrote in Naturethat "....research into new methods of providing additional sources of fresh water has become front page news." "...vast areas of California and other southern regions are short of water" B. In 2008, Shannon et al., wrote in Naturethat "One of the most pervasive problems afflicting people throughout the world is inadequate access to clean water and sanitation. Problems with water are expected to grow worse in the coming decades..." "1.2 billion people lack access to safe drinking water, 2.6 billion have little or no sanitation, millions of people die annually—3,900 children a day—from diseases transmitted through unsafe water or human excreta. Countless more are sickened from disease and contamination." "...water scarcity may be a watchword that prompts action ranging from wholesale population migration to war, unless new ways to supply clean water are found." C. In 2011, Elimelech and Phillip wrote in Sciencethat "Water scarcity is one of the most serious global challenges of our time. Presently, over one-third of the world's population lives in water-stressed countries and by 2025, this figure is predicted to rise to nearly two thirds." 1. A problem with SWRO for meeting global water demands is that it presently uses thermoelectric power which creates air pollutants and greenhouse gases. For example, "Current state-of-the-art SWRO plants consume between 3 and 4 kWh/m3and emit between 1.4 and 1.8 kg CO2per cubic meter of produced water. To put this in perspective, Spain would require as much as 4000 GWh annually to produce its projected desalination capacity of 1 billion m3/year." 2. Another problem, "A major problem associated with seawater intake is the impingement and entrainment of marine organisms." Underground beach wells or locating intakes in deep water are potential solutions. 3. Another problem, "The elevated salinity of SWRO brines (about twice that of seawater) and the chemicals used in pretreatment and membrane-cleaning protocols also pose environmental risks to organisms when discharged to the marine environment." Presently, too few studies exist to adequately characterize this problem. A. To determine whether or not desalination is a solution, we need to know the typical water consumptions per person. 1.In the U.S., according to the USGS the average is 80 to 100 gallons per day per person in a household. 2. Comparing this to USGS Maupin et al (see Global Hydrology lecture) where total off-stream water withdraws in the year 2010 were 355 billion gpd. With a population of 309M in 2010, this equates to over 1100 gpd per person. The order of magnitude difference is because the value in point 1 is water usage for individuals living in a household whereas point 2 accounts for all water usage including hydrothermal power, irrigation, etc. B.Local U.S. Solution: The large Ashkelon plant in Israel is now producing over 100M m3/year of freshwater, i.e., 72 million gpd. 1. In the U.S., if this water was used strictly for household usage, then the plant could supply a city of about one million people, i.e., Columbus Ohio (assuming we conserved water at a rate of 72 gpd per person). 2. If used in U.S. for all water withdrawals (e.g., irrigation, hydrothermal, etc.) then is only enough for a town of about 60,000 people. Global Solutions: This chart is from the United Nations and indicates water usage per person per year for several different countries. My red numbers indicate gallons per person per day. Using Ashkelon as an example desalination plant with its 72M gpd, the blue numbers indicate the number of Ashkelon plants required for the entire country.

What is a key difference between the resources of oil and water?

Add up the total water withdrawals per day and compare to river flows. 400B gal/day is 17,500 m3/s. This is about the same as the Mississippi River flow and roughly half of all river flows draining the U.S. Are these rivers experiencing significant declines in their discharge? That is, given that 400B gal/day is half of all river flows in the U.S., are these rivers experiencing a decline of half of their discharge compared to say a couple hundred years ago when U.S. population was only 2% of today's? Answer: No. So where is all of this water going that is being withdrawn? Answer: it is used and then passed through the user and back into the environment. At that point, however, it may not be of the same quality. It is put back either in the same location or evaporated and carried away by the atmosphere where it rains out over some other place. Oil, however, is being used and not replenished. W e will learn more about oil in a few more lectures. Note: Thermo-electric power has decreased because once-through systems are replaced with recirculating or dry systems; water efficient natural gas power is replacing coal power. -"Withdrawals in California were nearly 50 percent less between 2005 and 2010 primarily due to plant closures and upgrades to intakes and cooling systems implemented in order to comply with State regulations."

Indirect Measurement of Temperature

All oxygen atoms have 8 protons, but the nucleus might contain 8, 9, or 10 neutrons. "Light" oxygen-16, with 8 protons and 8 neutrons, is the most common isotope found in nature, followed by much lesser amounts of "heavy" oxygen-18, with 8 protons and 10 neutrons. The ratio (relative amount) of these two types of oxygen in water changes with the climate. By determining how the ratio of heavy and light oxygen in marine sediments, ice cores, or fossils is different from a universally accepted standard, scientists can learn something about climate changes that have occurred in the past. Evaporation and condensation are the two processes that most influence the ratio of heavy oxygen to light oxygen in the oceans. Water molecules are made up of two hydrogen atoms and one oxygen atom. Water molecules containing light oxygen evaporate slightly more readily than water molecules containing a heavy oxygen atom. At the same time, water vapor molecules containing the heavy variety of oxygen condense more readily. Water vapor gradually loses 18O as it travels from the equator to the poles. Because water molecules with heavy 18O isotopes in them condense more easily than normal water molecules, air becomes progressively depleted in 18O as it travels to high latitudes and becomes colder and drier. In turn, the snow that forms most glacial ice is also depleted in 18O. In polar ice cores, the measurement is relatively simple: less heavy oxygen in the frozen water means that temperatures were cooler.

Why Was California Experiencing Drought?

Another way of asking this question, is "why do we care about ocean temperatures?" Take an atmospheric sciences class to learn much more about the following... The Pacific Decadal Oscillation (PDO) is a many-year temperature phenomenon of the northern Pacific Ocean. As the name implies, the temperatures of the Pacific Ocean oscillate back and forth between warm and cold. Now, the ocean is in a cold phase, see map. Colder ocean temperatures wrap around a warmer core. This helps to create a high-pressure atmospheric ridge that migrates northward, away from California and up to Canada. The precipitation thus falls in Canada, and not in California. The PDO is not the only reason for California's drought, but is an important reason.http://news.nationalgeographic.com/news/2014/02/140213-california-drought-record-agriculture-pdo-climate/

California's Drought

Aqueducts delivering water from the melting snowpacks of the Sierra Nevada mountains to the coastal California cities were required to grow the state's economy. Because the snows fall during the winter, but the water is needed year round, dams were built to store the water from melting snow and thus provide water during the summer. Global warming is causing rain to fall, instead of snow, later into the calendar year (i.e., it rains in October instead of snowing). Warmer temperatures cause the snowpack to melt earlier in the calendar year (i.e., it begins melting in March). Combined, this means that the natural storage provided by snow sticking to the sides of mountains is shrinking. To compensate for this loss of natural storage, reservoirs need to be larger. The costs are in the billions of dollars. But, when drought comes, the problem is reversed. The natural climate system never supported the population (else aqueducts and dams would not have been built), thus the ongoing drought in California intensifies these challenges. As of November 30, 2015, all of California's reservoirs, combined, are at 38% of the capacity(see http://cdec.water.ca.gov/cgi-progs/reservoirs/RES). They are less than half full.

Why are arctic lakes losing storage?

Arctic lakes are losing storage, despite a slight increase in precipitation. The spatial pattern of lake loss strongly suggests that the melting of permafrost is driving the process (rather than evaporation). At first, permafrost melting increases lake storage, but continued melting breaches the underlying frozen ground allowing the lake to drain into the subsurface.

Applied Hydrology

At the intersection of science and society lies Applied Hydrology Ultimately, users need scientific knowledge, particularly users in economically challenged areas, e.g., Bangladesh & Pakistan. Concerns include overwatering and thus overusing groundwater while having lower yields.http://blogs.uw.edu/ceenews/2016/08/05/satellite-based-text-message-irrigation-advisory-system-helps-pakistani-farmers-stay-above-water/Farmers in the Indus Valley, Pakistan Prof. Faisal Hossain (UW) is leading a team that is sending weekly text messages to "More than 700 farmers in Pakistan who grow bananas, wheat and a variety of other crops." Example text, "Dear farmer friend, we would like to inform you that your wheat crop does not need irrigation due to sufficientrainfall during the past week." "In just four months, three of Hossain's graduate students developed open source software that gathers freely available NASA satellite data and other model data on precipitation, evaporation and weather data from the National Oceanic and Atmospheric Administration's National Center for Atmospheric Research. The software calculates daily and weekly reference precipitation and the evaporation of water from soil and plants. The data and corresponding maps are then downloaded by PCRWR officials, who analyze them along with information about the season, climate and weather forecast. Watering recommendations are then developed for specific regions in Pakistan."

Groundwater Depletion

Beneath coastal land, fresh water "floats"on salt water. Pumping causes the fresh/salt boundary to rise. Eventually, salt water may enter the pumping well. Salt water intrusion renders the water unpotable.

Direct Measurement of CO2and Indirect Measurement of Temperature, summary

CO2: Carbon dioxide is directly measured in the ice cores. The earth's previous atmosphere is preserved in air bubbles trapped inside the ice. Sampling these trapped gases provides a direct measurement of past atmospheres. Temperature: Temperature is indirectly observed in ice cores: the earth's previous temperatures are not trapped in the ice. The short version is "The ratio of "light" oxygen-16 to "heavy" oxygen-18 in a sample, for instance, reveals the global temperature when the ice formed; it takes colder temperatures for water vapor containing the lighter oxygen isotope to turn into precipitation." The next slide has the longer version. Summary of CO2 and Temperature:Carbon dioxide appears to have acted like a feedback during the cycles, reinforcing temperature changes initiated by natural variations in Earth's orbit. In contrast, carbon dioxide levels were nearly constant during the past several thousand years until human activities began emitting large amounts of carbon dioxide into the atmosphere, amplifying the natural greenhouse effect. Thus, while carbon dioxide may have acted as a feedback in the past, it is acting as a forcing in the current climate.

April -May, 2011 Ohio and Mississippi River Flood

Cairo, IL:This small town is at the confluence of the Ohio and Mississippi Rivers. It is entirely surrounded by levees. Rising flood waters on the Ohio threatened to overtop the levees and completely flood the town. Levee Detonation:To prevent Cairo flooding, the U.S. Army Corps of Engineers detonated the yellow sections of the levee, thus enabling river waters downstream of Cairo to escape onto the floodplain, which in turn allowed more upstream water to flow into the downstream channel. Did USACE have to do this?:Undergraduate students working in my team built a hydrodynamic model to test whether or not Cairo would have flooded. Model Inputs:Discharge measured at stream gauges located upstream of Cairo on the Ohio and Mississippi Rivers; downstream water elevations (stage) on the Mississippi; floodplain topography and channel bathymetry; roughness factor. Flooded Areas:Flooded areas in the model (left) match those observed in satellite images (right). This helps to validate the model. Detonation:Notice that floodplain west and south of Cairo is not flooded in top view, but is flooded in bottom view.Modeled flood extent (left) compared to NASA MODIS imaging (right). Dark blue represents flooding extent.

Water is Also Special Because:

Commonly, supply comes and goes with weather Resource so essential has little value -not worth transporting long distances -we take advantage of natural conveyance systems (i.e., rivers)

Drought:

Conceptual Definitions: these are general, e.g., "Drought is a protracted period of deficient precipitation resulting in extensive damage to crops, resulting in loss of yield." Operational Definitions: these are designed for policy makers, resource planners, etc. and can be tied to response measures such as implementing water conservation practices. "An operational definition for agriculture might compare daily precipitation values to evapotranspiration rates to determine the rate of soil moisture depletion, then express these relationships in terms of drought effects on plant behavior (i.e., growth and yield) at various stages of crop development."

Secondary porosity

Developed after rock formation. Fracturing. Faulting. Dissolution.

How Much Water is Amazon?

Enough water to elastically compress the crust ~10 cm every year!Amazon R. is 10x the Mississippi R.

Coastal Variability

Eustatic sea-level changes effect coasts worldwide. Inflation/deflation of mid-ocean ridge volumes. Glaciation/deglaciation traps or releases water. Pleistocene glaciations exposed all continental shelves.

Flood Frequency

Flood Frequency Analysis: 1.Use 20+ years of discharge data 2.Rank the discharge data from largest to smallest, giving the largest a rank of 1 and the next largest a rank of 2 and so on. 3.Recurrence interval is equal to (n+1)/m where n is the total number of years in the record and m is the rank. 4.Probability is 1/recurrence

Will There Be Water Wars?

Given the problems we've just briefly reviewed, it seems logical to suggest that countries will go to war over water. In fact, " In 2007, UN Secretary General Ban Ki Moon warned that "water scarcity ... is a potent fuel for wars and conflict." " Yet, Aaron Wolf of Oregon State indicates that the "only official war over water took place about 4,500 years ago. It was a conflict between the city-states of Lagash and Umma in modern day Iraq over the Tigris river." "In short, predictions of a W ater W orld W ar are overwrought. However, tensions over water usage can still exacerbate other existing regional conflicts." "According to our research, 24 of the world's 276 international river basins are already experiencing increased water variability. These 24 basins, which collectively serve about 332 million people, are at high risk of water related political tensions. The majority of the basins are located in northern and sub-Saharan Africa. A few others are located in the Middle East, south-central Asia, and South America."

Groundwater Flow

Groundwater flow occurs on a variety of scales. Local -Shallow flow over short times and distances. Intermediate -Flow of moderate depth, time, and distance. Regional -Deep, long-distance, long-duration flow.

Greenland and Antarctica ice melts.. How Much Sea Level Rise?

If all of Greenland's Ice Melted: -Sea level would rise about 6 meters If all of Antarctica's Ice Melted: -Sea level would rise about 60 meters

What is Reverse Osmosis?

Imagine that instead of sugar being poured into the left side of the U-tube, that salt is poured in. Under normal osmosis, the freshwater on the right side would flow into the salt water to equalize the pressures on both sides. Reverse osmosis applies pressure to the left side which overcomes the normal osmotic gradient thus allowing the water from the left side to flow to the right side, while leaving behind the NaCl on the left side. Note that the membrane is impermeable to salt, but permeable to water. This is a little different than filtration which can achieve theoretical perfect separation. "Reverse osmosis involves a diffusive mechanism, so that separation efficiency is dependent on solute concentration, pressure, and water flux rate.

How does the lack of measurements limit our ability to predict the land surface branch of the global hydrologic cycle?

In locations where gauge data is available, GCM precipitation and subsequent runoff miss streamflow by 100% The question is unanswered for ungauged wetlands, lakes, and reservoirs throughout the world.

How do meandering channels form?

Increased erosion on outer banks of curves causes curves to become more pronounced Erosion on the outer banks causes meanders to become progressively tighter; ultimately, the meander may be cut off to form an oxbow lake

Why do these concentrations increase only in the last 200 years, compared to this 2000 year record?

Industrial revolution and beyond.

Climate Change: What Has Happened Since 1998?

Investors Business Daily, Nov. 4, 2008, editorial, "The latest warming trend, which appears to have ended in 1998, is the result of the end of the Little Ice Age, which extended from roughly the 16th century to the 19th." Easterling and Wehner, 2009, Is the climate warming or cooling?, Geophys. Res. Lett., 36, "Numerous websites, blogs and articles in the media have claimed that the climate is no longer warming, and is now cooling. Here we show that periods of no trend or even cooling of the globally averaged surface air temperature are found in the last 34 years of the observed record, and in climate model simulations of the 20thand 21stcentury forced with increasing greenhouse gases. We show that the climate over the 21stcentury can and likely will produce periods of a decade or two where the globally averaged surface air temperature shows no trend or even slight cooling in the presence of longer-term warming."

Sea Level Rise Predictions

Measurements are from tide gauges and satellite altimeters; both corrected for glacial isostatic rebound Altimeters exist from 1993 to 2006 giving 3.3 ±0.4 mm/year IPCC projected a best-estimate rise of less than 2 mm/year, closest IPCC model "included land ice uncertainty"(see tiny little dashed grey line)•The rate of rise for the past 20 years of the reconstructed sea level is 25% faster than the rate of rise in any 20-year period in the preceding 115 years. "Again, we caution that the time interval of overlap is short, so that internal decadal climate variability could cause much of the discrepancy; it would be premature to conclude that sea level will continue to follow this "upper limit" line in future." "The largest contributions to the rapid rise come from ocean thermal expansion and the melting from nonpolar glaciers as a result of the warming mentioned above. Although the ice sheet contribution has been small, observations are indicating that it is rapidly increasing, with contributions both from Greenland and Antarctica."

Comparing Dams

Not all dams and reservoirs are alike. Balbina is in a low-relief area with little sediment erosion and deposition. Rindge Dam is in southern California on Malibu Creek; high erosion and sedimentation rates have in-filled behind the dam. Why has sediment filled in Rindge and not Balbina? Referring back to the sedimentary rocks and floodplain lectures, what size of particles do you expect to find in the filled-in Rindge reservoir? Balbina is an "ecological disaster", what sort of problems do you think might exist at the Rindge Dam? What do you think the dam does to upstream fish migration (i.e., endangered steelhead trout) or to sediment delivery to the downstream beach?

Climate models

Predict temperatures and sea level based on physics Models are not 'tuned' to data since 1990 Used to predict how changes in the atmosphere will affect the planet, i.e., "anthropogenic perturbations of the Earth's radiation budget"

Carbon Dioxide Predictions

Predictions from models are dashed lines. "Carbon dioxide concentration follows the projections almost exactly" Global mean CO2is slightly lower than Hawaii because continents are mostly in the northern hemisphere.

Balbina Reservoir

Prior to dam closure, Uatumã River flow was 450 m3/s and drained a 19,100 km2 watershed. Lake Balbina average depth is 7.4 m, thus reservoir was drained in early 1998.

Dams also..

Produce electricity Impound sediments Help control floodwaters Produce greenhouse gases Provide recreation Store water for irrigation, industry, and potable uses

Why the Concerns with Water?

Rainfall and hence the replenishment of surface and ground waters is not distributed evenly amongst all U.S. people and definitely not amongst all global people. Example: northeastern U.S. and our part of the Midwest has plenty of water whereas California and Arizona have much less water and yet still sizable populations. If it rains at some given location, then there is a chance of resupplying the withdrawn water. If rainfall is limited, then resupply will not happen and the water users will eventually need another solution (see desalination lecture) or move. Example: Phoenix, Las Vegas, and all of Southern California have a population of 25M yet they will run out of water. Furthermore, irrigated areas of the central states will also run out of water. The big challenging question is "when?".

Connections of Ice, Temperature, and Sea Level Rise

Rate of Sea Level Rise -1.8 mm/yr for the past 50 years -3.1 mm/yr during the 1990s -On these time scales, contributions are mostly from thermal expansion, melting ice, and terrestrial reservoir supply Sources of Sea Level Rise: -Melting of mountain glaciers •0.45 mm/yr past 40-50 years; 0.8 mm/yr during 1990s -Melting Greenland and Antarctica •0.2 mm/yr and 0.2 mm/yr, respectively, during 1990s -Thermal expansion of oceans; warm water is less dense than cold water, i.e., warming water expands it (think of a hot air balloon) •0.4 mm/yr past 40-50 years; 1.5 mm/yr during 1990s -Terrestrial water supply: •Sum the above during 1990s: 3.1 = 0.8 + 0.2 + 0.2 + 1.5 + ? -? = about 0.4 mm/yr •Reservoir filling would take water away from the oceans, thus cause a decrease in sea level •Groundwater mining would ultimately yield water for the oceans via runoff •Draining of wetlands provides water to the oceans •Some large lakes are experiencing a decrease in water levels, thus increasing the sea level •But this is a lot of guessing!

How do rivers expend their energy?

Rivers expend their energy by either cutting down into the rocks below and forming canyons or by cutting sideways and forming floodplains.

Rivers provide..

Rivers provide water for crop production, i.e., irrigation Transportation routes to move commodities between farms and cities Problems develop due to strong variability in river flows -before 1900 mostly climate related -after 1900 human diversions of water compounded by climate variability

Risks of Sea Level Rise

Sea level rise or inundation zones were calculated from the Global Land One-km Base Elevation (GLOBE) digital elevation model (DEM) (Hastings and Dunbar 1998), a raster elevation dataset covering the entire world. -Cells in GLOBE have a spatial resolution of 30 arc seconds of latitude and longitude (approximately one kilometer at the Equator), with each land cell in the grid assigned an elevation value (meters) in whole number increments. -Inundation zones depicted on all static map products and the regional maps in the map animations were derived from GLOBE. Inundation zones for the entire globe in the world map animation were calculated from the ETOPO2 raster elevation dataset developed by the National Geophysical Data Center (NGDC) (NGDC 2001), which has a coarser resolution of two minutes of latitude and longitude (approximately 1.8 km at the Equator). Populations in the inundation zones were estimated from LandScan, a global population dataset developed by the Oak Ridge National Laboratory Global Population Project for estimating populations at risk (Dobson et al. 2000). -LandScan was compiled from the best available population census data for each country that were then disaggregated into cells based on land cover type, proximity to roads, slope, and nighttime lights. -The most recent version of LandScan (2004) was used for all population calculations in the inundation zones. LandScan may also be displayed under the inundation zone layers in the map animations.

What is a key difference between groundwater and surface water?

Surface water is replenished within hours of when it rains whereas groundwater is replenished in days to centuries, depending on the depth of the aquifer (deeper taking longer to replenish). Some groundwater can be used up and not replenished whereas surface water can be replenished within a season. -For example: irrigation pumping water from an aquifer can be turned-off, but the aquifer water may not refill for decades, e.g., California's Central Valley. The same irrigation pumping water from a river can be turned-off and the river flow might recover within a season.

Where does LA get some of its water?

Surface water, groundwater, and snow melt, Owens Valley

Where is the worlds largest discharge?

The Amazon has the world's Largest Discharge, 10% to 20% of World's runoff to oceans! About 17% of 6,000,000 km2 annually subjected to inundation

Predictions of Future Climate

The data available for the period since 1990 raise concerns that the climate system, in particular sea level, may be responding more quickly to climate change than our current generation of models indicates.

Water and Energy budget

The global water budget is intrinsically linked to the global energy budget. When water changes among its different phases (solid, liquid, and gas) energy is absorbed or released, thus affecting the energy budget. A simple energy budget for the Earth is (Sellers, 1965): Rn = G + LE + H Rn is net radiation -the sum of incoming solar and long wave radiation minus reflected solar and emitted long wave radiation G is surface heat flux -the energy used to warm soil, or water in the case of a surface-water body LE is latent heat flux -the energy used to evaporate water -Latent heat flux is the product of latent heat of vaporization (λ) and evapotranspiration rate (ET) •LE = λET •Evapotranspiration provides a direct link between the energy-budget and the water-budget equations because it appears in both equations. H is sensible heat flux -the energy used to warm air The equation states that available energy at the Earth's surface goes to heating the surface, warming the air, and evaporating water. These equations form the basis of general circulation computer models that are used to predict climate trends.

Base Level

The lowest point to which a stream can erode. Ultimate base level is defined by the position of sea level. Streams cannot erode below sea level. A lake serves as a local (or temporary) base level. Base level changes cause stream readjustments. Raising base level results in an increase in deposition. Lowering base level accelerates erosion.

Water Table Topography

The water table is not flat; it is a sloping surface. The water table is a subdued replica of the topography. The water table is high where the land is high. The water table is low where the land is low. Water flows from higher elevations to lower elevations. Topography is useful for estimating groundwater flow.

Temperature Predictions

These are the global mean surface temperature, including both oceans and land Measurements are from NASA GISS (land temperatures) and Hadley Centre/Climatic Research Unit (sea surface temperatures) GISS data: data.giss.nasa.gov/gistemp/ -Global surface temperature with monthly resolution for the period since 1880, when a reasonably global distribution of meteorological stations was established -Input data for the analysis, collected by many national meteorological services around the world, is the unadjusted data of the Global Historical Climatology Network (Peterson and Vose, 1997 and 1998) -"we adjust the non-rural stations in such a way that their longterm trend of annual means is as close as possible to that of the mean of the neighboring rural stations. Non-rural stations that cannot be adjusted are dropped." -"The temperature index is formed by combining the meteorological station measurements over land with sea surface temperatures obtained primarily from satellite measurements" Measurements indicate a 0.33°C rise for the 16 years since 1990 (0.021°C/yr)

Toledo, Ohio; August 2-4, 2014

Toledo uses Lake Erie water for much of its required daily usage. "The algae and bacteria responsible for blooms, including the one that created Toledo's tap water mess—a type of bacteria known as Microcystis—need warm temperatures and the nutrients phosphorus and nitrogen to grow. Microcystis is a kind of cyanobacteria, often mistakenly referred to as blue-green algae." NGS. The result of these Harmful Algal Blooms (HABs) was that 400,000 residents of Toledo were without drinking water for 3 days. What is the potential future of HABs in Lake Erie? What happens with global warming? What happens with fertilizer runoff from fields into the rivers that feed into Lake Erie?•Why did only Toledo experience this problem and not other cities within the HABs? Did winds whip of the water and push the HABs downward and into Toledo's water intake and not other cities' intakes? The cost is still being calculated, but restaurants and businesses had to shut down due to the lack of water.

Thermal Distillation:

Uses heat to evaporate water leaving behind the salts. Is used mostly in coastal regions where energy supply is cheap.

Reverse Osmosis

Uses pressure to overcome the osmotic gradient between saltwater and freshwater separated by a semipermeable membrane. Accounts for over 50% of the installed desalination capacity. Requires less energy than thermal distillation.

Aquifer

a body of water-saturated, porous, and permeable rock or regolith. often used as source of freshwater

saturated zone:

all openings and spaces are filled with water

Groundwater:

all subsurface water contained in spaces within bedrock and regolith

hydrologic droughts

deficit in runoff and/or groundwater resources)

What is the role of wetland, lake, and river water storage as a regulator of biogeochemical cycles, such as carbon and nutrients?

e.g., Rivers outgas as well as transport Carbon. Ignoring water borne C fluxes, favoring land-atmosphere only, yields overestimates of terrestrial C accumulation Results:470 Tg C/yr all Basin; 13 x more C by outgassing than by discharge. But what are seasonal and global variations? If extrapolate Amazon case to global wetlands, = 0.9 Gt C/yr, 3x larger than previous global estimates; Tropics are in balance, not a C Sink?

confined aquifer

if overlain by impermeable rock units called aquicludes

unconfined aquifer

if water is free to rise to its natural level

permeability:

measure of how easily fluids pass through rock or regolith The ease of water flow due to pore interconnectedness. High-permeability material allows water to flow readily. Water flows slowly through low-permeability material. Many large and straight flow paths enhance permeability.

porosity:

percentage of the total volume of rock or regolith that consists of open spaces, or pores

Groundwater contamination:

rainwater leaching toxic chemicals in an unlined landfill leaking septic tank ' agricultural chemicals underground storage tanks contamination affects all wells and streams that lie downslope pollutants may be removed where groundwater moves through permeable fine sand

unsaturated zone (zone of aeration):

spaces are filled mainly with air

Drainage basin:

the total area from which water flows into a stream or river

In 2009, there was about _____ acre-feet of water stored. This is the same as _____ cubic kilometers.

three billion - 3700

water table:

top of the saturated zone high under mountains, low under valleys

Divide:

topographic high that separates adjacent drainage basins

High Plains Aquifer:

underlies eight states (TX, NM, OK, KS, CO, WY, SD) total area: 450,595 km2or 174,050 mi2 average thickness: 58 m or 190 ft volume of drainable water (1980): 4009 km3or 962 mi3 important source for freshwater mining has caused water level to drop