- A Tragic Loss. The Tesla Team June ... Tesla informed NHTSA about the incident immediately after it...
A Tragic LossJune 30, 2016We learned yesterday evening that NHTSA is opening a preliminary evaluation into the performance of Autopilot during a recent fatal crash that occurred in a Model S. This is the first known fatality in just over 130 million miles where Autopilot was activated. Among all vehicles in the US, there is a fatality every 94 million miles. Worldwide, there is a fatality approximately every 60 million miles. It is important to emphasize that the NHTSA action is simply a preliminary evaluation to determine whether the system worked according to expectations.
Following our standard practice, Tesla informed NHTSA about the incident immediately after it occurred. What we know is that the vehicle was on a divided highway with Autopilot engaged when a tractor trailer drove across the highway perpendicular to the Model S. Neither Autopilot nor the driver noticed the white side of the tractor trailer against a brightly lit sky, so the brake was not applied. The high ride height of the trailer combined with its positioning across the road and the extremely rare circumstances of the impact caused the Model S to pass under the trailer, with the bottom of the trailer impacting the windshield of the Model S. Had the Model S impacted the front or rear of the trailer, even at high speed, its advanced crash safety system would likely have prevented serious injury as it has in numerous other similar incidents.
It is important to note that Tesla disables Autopilot by default and requires explicit acknowledgement that the system is new technology and still in a public beta phase before it can be enabled. When drivers activate Autopilot, the acknowledgment box explains, among other things, that Autopilot “is an assist feature that requires you to keep your hands on the steering wheel at all times," and that "you need to maintain control and responsibility for your vehicle” while using it. Additionally, every time that Autopilot is engaged, the car reminds the driver to “Always keep your hands on the wheel. Be prepared to take over at any time.” The system also makes frequent checks to ensure that the driver's hands remain on the wheel and provides visual and audible alerts if hands-on is not detected. It then gradually slows down the car until hands-on is detected again.
We do this to ensure that every time the feature is used, it is used as safely as possible. As more real-world miles accumulate and the software logic accounts for increasingly rare events, the probability of injury will keep decreasing. Autopilot is getting better all the time, but it is not perfect and still requires the driver to remain alert. Nonetheless, when used in conjunction with driver oversight, the data is unequivocal that Autopilot reduces driver workload and results in a statistically significant improvement in safety when compared to purely manual driving.
The customer who died in this crash had a loving family and we are beyond saddened by their loss. He was a friend to Tesla and the broader EV community, a person who spent his life focused on innovation and the promise of technology and who believed strongly in Tesla’s mission. We would like to extend our deepest sympathies to his family and friends.
Top 10 Posts This Month
- Russia and Brazil Hit Hardest in Sovereign Risk Ratings...
- The ultra-lethal drones of the future | New York Post 2014 article
- reprint of: Drones very small to large
- Category:3D printing
- 3D printing - Wikipedia
- Friday April 14th 2017: The 10 most read articles in the last 24 hours at this site
- Friday May 5th 2017: The most read articles in the last 24 hours at this site
- Wednesday April 26th 2017: Most read articles at this site in the last 24 hours
- Joan Baez - We shall overcome: Youtube: 3,229,728 views
- Boeing CH-47 Chinook - Wikipedia
Thursday, June 30, 2016
The news tonight in San Francisco said that Tesla thinks the Self driving mechanism mistook the Semi truck for an overhead sign which caused the fatality.
The problem is that when people expect more than the Tesla can deliver they are going to die or be maimed. Though it is true it will stay in it's lane 5 cars behind the car in front of them, if you aren't vigilant you are still going to die or be maimed in an emergency if you are sitting in the driver's seat or riding in that Tesla.
It reminds me of the people that put their motor home in cruise control and went to cook their meal while driving with no one at the wheel. If you don't understand the technology in a vehicle it's likely you are going to be dead or maimed soon.
I'm not sure how you train someone to drive the limited form of a self driving car that Tesla is. I was driving next to a Tesla today going across the Bay Bridge into San Francisco and noticed a Tesla driver with no hands on the wheel (likely no feet on the pedals either) tooling along next to me. He had a funny look on his face like this was a strain for him (and it should have been) if he wants to stay alive to do this again! So, I realized this driver had no hands on the wheel or likely feet on the pedals. If you are driving next to someone like this: "How do you feel about this as a driver in the next lane?"
I think it might be necessary to train drivers what to look for to stay alive while in self driving mode. I think most people likely aren't ready for this yet (if they want to stay alive).
If you understand that when you are in self driving mode it is sort of like if your Macbook pro laptop was driving your car.
Would you be okay if your Macbook pro laptop drove you home? Haven't you ever seen glitches while you were using one? One of those glitches just killed someone in the news. here it is:
begin quote from:Honolulu Star-Advertiser5 hours ago... mode allows the ...park on command Tesla conceded that the... of Defects...nation’s roads for self-driving cars, an anticipated...boon to safety because they’ll eliminate...about 94 percent of...
- NBC Bay Area22 hours ago
- San Antonio Express-News22 hours ago
Joshua D. Brown, of Canton, Ohio, died in the accident May 7 in Williston, Florida, when his car’s cameras failed to distinguish the white side of a turning tractor-trailer from a brightly lit sky and didn’t automatically activate its brakes, according to government records obtained today.
Frank Baressi, 62, the driver of the truck and owner of Okemah Express LLC, said the Tesla driver was “playing Harry Potter on the TV screen” at the time of the crash and driving so quickly that “he went so fast through my trailer I didn’t see him.”
“It was still playing when he died and snapped a telephone pole a quarter mile down the road,” Baressi told The Associated Press in an interview from his home in Palm Harbor, Florida. He acknowledged he couldn’t see the movie, only heard it.
Tesla Motors Inc. said it is not possible to watch videos on the Model S touch screen. There was no reference to the movie in initial police reports.
Brown’s published obituary described him as a member of the Navy SEALs for 11 years and founder of Nexu Innovations Inc., working on wireless Internet networks and camera systems. In Washington, the Pentagon confirmed Brown’s work with the SEALs and said he left the service in 2008.
Brown was an enthusiastic booster of his 2015 Tesla Model S and in April credited its sophisticated Autopilot system for avoiding a crash when a commercial truck swerved into his lane on an interstate. He published a video of the incident online. “Hands down the best car I have ever owned and use it to its full extent,” Brown wrote.
Tesla didn’t identify Brown but described him in a statement as “a friend to Tesla and the broader EV (electric vehicle) community, a person who spent his life focused on innovation and the promise of technology and who believed strongly in Tesla’s mission.” It also stressed the uncertainty about its new system, noting that drivers must manually enable it: “Autopilot is getting better all the time, but it is not perfect and still requires the driver to remain alert.”
A man answering the door at Brown’s parents house who did not identify himself said he had no comment.
Tesla founder Elon Musk expressed “Our condolences for the tragic loss” in a tweet late today.
Preliminary reports indicate the crash occurred when Baressi’s rig turned left in front of Brown’s Tesla at an intersection of a divided highway where there was no traffic light, the National Highway Traffic Safety Administration said. Brown died at the scene of the crash, which occurred May 7 in Williston, Florida, according to a Florida Highway Patrol report. The city is southwest of Gainesville.
By the time firefighters arrived, the wreckage of the Tesla — with its roof sheared off completely — had come to rest in a nearby yard hundreds of feet from the crash site, assistant chief Danny Wallace of the Williston Fire Department told The Associated Press. The driver was pronounced dead, “Signal 7” in the local firefighters’ jargon, and they respectfully covered the wreckage and waited for crash investigators to arrive.
The company said this was the first known death in over 130 million miles of Autopilot operation. It said the NHTSA investigation is a preliminary inquiry to determine whether the system worked as expected.
Tesla says that before Autopilot can be used, drivers have to acknowledge that the system is an “assist feature” that requires a driver to keep both hands on the wheel at all times. Drivers are told they need to “maintain control and responsibility for your vehicle” while using the system, and they have to be prepared to take over at any time, the statement said.
Autopilot makes frequent checks, making sure the driver’s hands are on the wheel, and it gives visual and audible alerts if hands aren’t detected, and it gradually slows the car until a driver responds, the statement said.
The Autopilot mode allows the Model S sedan and Model X SUV to steer itself within a lane, change lanes and speed up or slow down based on surrounding traffic or the driver’s set speed. It can automatically apply brakes and slow the vehicle. It can also scan for parking spaces and parallel park on command
Tesla conceded that the Autopilot feature is not perfect, but said in the statement that it’s getting better all the time. “When used in conjunction with driver oversight, the data is unequivocal that Autopilot reduces driver workload and results in a statistically significant improvement in safety,” the company said.
NHTSA’s Office of Defects is handling the investigation. The opening of the preliminary evaluation shouldn’t be construed as a finding that the government believes the Model S is defective, NHTSA said in a statement.
The Tesla death comes as NHTSA is taking steps to ease the way onto the nation’s roads for self-driving cars, an anticipated sea-change in driving where Tesla has been on the leading edge. Self-driving cars have been expected to be a boon to safety because they’ll eliminate human errors. Human error is responsible for about 94 percent of crashes.
Musk has been bullish about Autopilot, even as Tesla warns owners the feature is not for all conditions and not sophisticated enough for the driver to check out.
This spring, Musk said the feature reduced the probability of having an accident by 50 percent, without detailing his calculations. In January, he said that Autopilot is “probably better than a person right now.”
One of Tesla’s advantages over competitors is that its thousands of cars feed real-world performance information back to the company, which can then fine-tune the software that runs Autopilot.
This is not the first time automatic braking systems have malfunctioned, and several have been recalled to fix problems. In November, for instance, Toyota had to recall 31,000 full-sized Lexus and Toyota cars because the automatic braking system radar mistook steel joints or plates in the road for an object ahead and put on the brakes. Also last fall, Ford recalled 37,000 F-150 pickups because they braked with nothing in the way. The company said the radar could become confused when passing a large, reflective truck.
The technology relies on multiple cameras, radar, laser and computers to sense objects and determine if they are in the car’s way, said Mike Harley, an analyst at Kelley Blue Book. Systems like Tesla’s, which rely heavily on cameras, “aren’t sophisticated enough to overcome blindness from bright or low contrast light,” he said.
Harley called the death unfortunate, but said that more deaths can be expected as the autonomous technology is refined.
Shares of Tesla Motors Inc. fell $6.77, or 3.2 percent, in after-hours trading after news of the crash was released. During the trading day, the stock was up 1 percent at $212.28.
Karl Brauer, a senior analyst with Kelley Blue Book, said the accident is a huge blow to Tesla’s reputation.
“They have been touting their safety and they have been touting their advanced technology,” he said. “This situation flies in the face of both.”
Brauer said Tesla will have to repair the damage in two ways. First, the company needs to make sure its customers understand that autopilot is meant to assist drivers, not to fully take over for them. Second, the company should update the cars’ software so autopilot will turn off if it senses the driver’s hands aren’t on the wheel for a certain period of time. Mercedes-Benz’s driver assist system is among those that require drivers’ hands to be on the wheel.
Krisher reported from Detroit. Associated Press writers Justin Pritchard in Los Angeles, Lolita Baldor and Ted Bridis in Washington, Dee-Ann Durbin in Detroit, Jason Dearen in Gainsville, Florida, and Tamara Lush in Palm Harbor, Florida, contributed to this report.
- en.wikipedia.org/wiki/AquiferAn aquifer is an underground layer of water-bearing permeable rock, rock fractures or unconsolidated...
AquiferFrom Wikipedia, the free encyclopedia
- 1 Depth
- 2 Classification
- 3 Groundwater in rock formations
- 4 Human dependence on groundwater
- 5 Subsidence
- 6 Saltwater intrusion
- 7 Salination
- 8 Examples
- 9 See also
- 10 References
- 11 External links
DepthAquifers may occur at various depths. Those closer to the surface are not only more likely to be used for water supply and irrigation, but are also more likely to be topped up by the local rainfall. Many desert areas have limestone hills or mountains within them or close to them that can be exploited as groundwater resources. Part of the Atlas Mountains in North Africa, the Lebanon and Anti-Lebanon ranges between Syria and Lebanon, the Jebel Akhdar (Oman) in Oman, parts of the Sierra Nevada and neighboring ranges in the United States' Southwest, have shallow aquifers that are exploited for their water. Overexploitation can lead to the exceeding of the practical sustained yield; i.e., more water is taken out than can be replenished. Along the coastlines of certain countries, such as Libya and Israel, increased water usage associated with population growth has caused a lowering of the water table and the subsequent contamination of the groundwater with saltwater from the sea.
The beach provides a model to help visualize an aquifer. If a hole is dug into the sand, very wet or saturated sand will be located at a shallow depth. This hole is a crude well, the wet sand represents an aquifer, and the level to which the water rises in this hole represents the water table.
In 2013 large freshwater aquifers were discovered under continental shelves off Australia, China, North America and South Africa. They contain an estimated half a million cubic kilometers of “low salinity” water that could be economically processed into potable water. The reserves formed when ocean levels were lower and rainwater made its way into the ground in land areas that were not submerged until the ice age ended 20,000 years ago. The volume is estimated to be 100x the amount of water extracted from other aquifers since 1900.
ClassificationThe above diagram indicates typical flow directions in a cross-sectional view of a simple confined or unconfined aquifer system. The system shows two aquifers with one aquitard (a confining or impermeable layer) between them, surrounded by the bedrock aquiclude, which is in contact with a gaining stream (typical in humid regions). The water table and unsaturated zone are also illustrated. An aquitard is a zone within the earth that restricts the flow of groundwater from one aquifer to another. An aquitard can sometimes, if completely impermeable, be called an aquiclude or aquifuge. Aquitards are composed of layers of either clay or non-porous rock with low hydraulic conductivity.
Saturated versus unsaturatedGroundwater can be found at nearly every point in the Earth's shallow subsurface to some degree, although aquifers do not necessarily contain fresh water. The Earth's crust can be divided into two regions: the saturated zone or phreatic zone (e.g., aquifers, aquitards, etc.), where all available spaces are filled with water, and the unsaturated zone (also called the vadose zone), where there are still pockets of air that contain some water, but can be filled with more water.
Saturated means the pressure head of the water is greater than atmospheric pressure (it has a gauge pressure > 0). The definition of the water table is the surface where the pressure head is equal to atmospheric pressure (where gauge pressure = 0).
Unsaturated conditions occur above the water table where the pressure head is negative (absolute pressure can never be negative, but gauge pressure can) and the water that incompletely fills the pores of the aquifer material is under suction. The water content in the unsaturated zone is held in place by surface adhesive forces and it rises above the water table (the zero-gauge-pressure isobar) by capillary action to saturate a small zone above the phreatic surface (the capillary fringe) at less than atmospheric pressure. This is termed tension saturation and is not the same as saturation on a water-content basis. Water content in a capillary fringe decreases with increasing distance from the phreatic surface. The capillary head depends on soil pore size. In sandy soils with larger pores, the head will be less than in clay soils with very small pores. The normal capillary rise in a clayey soil is less than 1.80 m (six feet) but can range between 0.3 and 10 m (one and 30 ft).
The capillary rise of water in a small-diameter tube involves the same physical process. The water table is the level to which water will rise in a large-diameter pipe (e.g., a well) that goes down into the aquifer and is open to the atmosphere.
Aquifers versus aquitardsAquifers are typically saturated regions of the subsurface that produce an economically feasible quantity of water to a well or spring (e.g., sand and gravel or fractured bedrock often make good aquifer materials).
An aquitard is a zone within the earth that restricts the flow of groundwater from one aquifer to another. A completely impermeable aquitard is called an aquiclude or aquifuge. Aquitards comprise layers of either clay or non-porous rock with low hydraulic conductivity.
In mountainous areas (or near rivers in mountainous areas), the main aquifers are typically unconsolidated alluvium, composed of mostly horizontal layers of materials deposited by water processes (rivers and streams), which in cross-section (looking at a two-dimensional slice of the aquifer) appear to be layers of alternating coarse and fine materials. Coarse materials, because of the high energy needed to move them, tend to be found nearer the source (mountain fronts or rivers), whereas the fine-grained material will make it farther from the source (to the flatter parts of the basin or overbank areas - sometimes called the pressure area). Since there are less fine-grained deposits near the source, this is a place where aquifers are often unconfined (sometimes called the forebay area), or in hydraulic communication with the land surface.
Confined versus unconfinedThere are two end members in the spectrum of types of aquifers; confined and unconfined (with semi-confined being in between). Unconfined aquifers are sometimes also called water table or phreatic aquifers, because their upper boundary is the water table or phreatic surface. (See Biscayne Aquifer.) Typically (but not always) the shallowest aquifer at a given location is unconfined, meaning it does not have a confining layer (an aquitard or aquiclude) between it and the surface. The term "perched" refers to ground water accumulating above a low-permeability unit or strata, such as a clay layer. This term is generally used to refer to a small local area of ground water that occurs at an elevation higher than a regionally extensive aquifer. The difference between perched and unconfined aquifers is their size (perched is smaller). Confined aquifers are aquifers that are overlain by a confining layer, often made up of clay. The confining layer might offer some protection from surface contamination.
If the distinction between confined and unconfined is not clear geologically (i.e., if it is not known if a clear confining layer exists, or if the geology is more complex, e.g., a fractured bedrock aquifer), the value of storativity returned from an aquifer test can be used to determine it (although aquifer tests in unconfined aquifers should be interpreted differently than confined ones). Confined aquifers have very low storativity values (much less than 0.01, and as little as 10−5), which means that the aquifer is storing water using the mechanisms of aquifer matrix expansion and the compressibility of water, which typically are both quite small quantities. Unconfined aquifers have storativities (typically then called specific yield) greater than 0.01 (1% of bulk volume); they release water from storage by the mechanism of actually draining the pores of the aquifer, releasing relatively large amounts of water (up to the drainable porosity of the aquifer material, or the minimum volumetric water content).
Isotropic versus anisotropicIn isotropic aquifers or aquifer layers the hydraulic conductivity (K) is equal for flow in all directions, while in anisotropic conditions it differs, notably in horizontal (Kh) and vertical (Kv) sense.
Semi-confined aquifers with one or more aquitards work as an anisotropic system, even when the separate layers are isotropic, because the compound Kh and Kv values are different (see hydraulic transmissivity and hydraulic resistance).
When calculating flow to drains  or flow to wells  in an aquifer, the anisotropy is to be taken into account lest the resulting design of the drainage system may be faulty.
Groundwater in rock formationsGroundwater may exist in underground rivers (e.g., caves where water flows freely underground). This may occur in eroded limestone areas known as karst topography, which make up only a small percentage of Earth's area. More usual is that the pore spaces of rocks in the subsurface are simply saturated with water — like a kitchen sponge — which can be pumped out for agricultural, industrial, or municipal uses.
If a rock unit of low porosity is highly fractured, it can also make a good aquifer (via fissure flow), provided the rock has a hydraulic conductivity sufficient to facilitate movement of water. Porosity is important, but, alone, it does not determine a rock's ability to act as an aquifer. Areas of the Deccan Traps (a basaltic lava) in west central India are good examples of rock formations with high porosity but low permeability, which makes them poor aquifers. Similarly, the micro-porous (Upper Cretaceous) Chalk of south east England, although having a reasonably high porosity, has a low grain-to-grain permeability, with its good water-yielding characteristics mostly due to micro-fracturing and fissuring.
Human dependence on groundwater
Fresh-water aquifers, especially those with limited recharge by snow or rain, also known as meteoric water, can be over-exploited and depending on the local hydrogeology, may draw in non-potable water or saltwater intrusion from hydraulically connected aquifers or surface water bodies. This can be a serious problem, especially in coastal areas and other areas where aquifer pumping is excessive. In some areas, the ground water can become contaminated by arsenic and other mineral poisons.
Aquifers are critically important in human habitation and agriculture. Deep aquifers in arid areas have long been water sources for irrigation (see Ogallala below). Many villages and even large cities draw their water supply from wells in aquifers.
Municipal, irrigation, and industrial water supplies are provided through large wells. Multiple wells for one water supply source are termed "wellfields", which may withdraw water from confined or unconfined aquifers. Using ground water from deep, confined aquifers provides more protection from surface water contamination. Some wells, termed "collector wells," are specifically designed to induce infiltration of surface (usually river) water.
Aquifers that provide sustainable fresh groundwater to urban areas and for agricultural irrigation are typically close to the ground surface (within a couple of hundred metres) and have some recharge by fresh water. This recharge is typically from rivers or meteoric water (precipitation) that percolates into the aquifer through overlying unsaturated materials.
Occasionally, sedimentary or "fossil" aquifers are used to provide irrigation and drinking water to urban areas. In Libya, for example, Muammar Gaddafi's Great Manmade River project has pumped large amounts of groundwater from aquifers beneath the Sahara to populous areas near the coast. Though this has saved Libya money over the alternative, desalination, the aquifers are likely to run dry in 60 to 100 years. Aquifer depletion has been cited as one of the causes of the food price rises of 2011.
SubsidenceIn unconsolidated aquifers, groundwater is produced from pore spaces between particles of gravel, sand, and silt. If the aquifer is confined by low-permeability layers, the reduced water pressure in the sand and gravel causes slow drainage of water from the adjoining confining layers. If these confining layers are composed of compressible silt or clay, the loss of water to the aquifer reduces the water pressure in the confining layer, causing it to compress from the weight of overlying geologic materials. In severe cases, this compression can be observed on the ground surface as subsidence. Unfortunately, much of the subsidence from groundwater extraction is permanent (elastic rebound is small). Thus, the subsidence is not only permanent, but the compressed aquifer has a permanently reduced capacity to hold water.
Saltwater intrusionMain article: Saltwater intrusionAquifers near the coast have a lens of freshwater near the surface and denser seawater under freshwater. Seawater penetrates the aquifer diffusing in from the ocean and is denser than freshwater. For porous (i.e., sandy) aquifers near the coast, the thickness of freshwater atop saltwater is about 40 feet (12 m) for every 1 ft (0.30 m) of freshwater head above sea level. This relationship is called the Ghyben-Herzberg equation. If too much ground water is pumped near the coast, salt-water may intrude into freshwater aquifers causing contamination of potable freshwater supplies. Many coastal aquifers, such as the Biscayne Aquifer near Miami and the New Jersey Coastal Plain aquifer, have problems with saltwater intrusion as a result of overpumping and sea level rise.
Surface irrigation water normally contains salts in the order of 0.5 g/l or more and the annual irrigation requirement is in the order of 10000 m³/ha or more so the annual import of salt is in the order of 5000 kg/ha or more.
Under the influence of continuous evaporation, the salt concentration of the aquifer water may increase continually and eventually cause an environmental problem.
For salinity control in such a case, annually an amount of drainage water is to be discharged from the aquifer by means of a subsurface drainage system and disposed of through a safe outlet. The drainage system may be horizontal (i.e. using pipes, tile drains or ditches) or vertical (drainage by wells). To estimate the drainage requirement, the use of a groundwater model with an agro-hydro-salinity component may be instrumental, e.g. SahysMod.
ExamplesGreat Artesian Basin situated in Australia is arguably the largest groundwater aquifer in the world (over 1.7 million km²). It plays a large part in water supplies for Queensland and remote parts of South Australia.
The Guarani Aquifer, located beneath the surface of Argentina, Brazil, Paraguay, and Uruguay, is one of the world's largest aquifer systems and is an important source of fresh water. Named after the Guarani people, it covers 1,200,000 km², with a volume of about 40,000 km³, a thickness of between 50 m and 800 m and a maximum depth of about 1,800 m.
Aquifer depletion is a problem in some areas, and is especially critical in northern Africa; see the Great Manmade River project of Libya for an example. However, new methods of groundwater management such as artificial recharge and injection of surface waters during seasonal wet periods has extended the life of many freshwater aquifers, especially in the United States.
The Ogallala Aquifer of the central United States is one of the world's great aquifers, but in places it is being rapidly depleted by growing municipal use, and continuing agricultural use. This huge aquifer, which underlies portions of eight states, contains primarily fossil water from the time of the last glaciation. Annual recharge, in the more arid parts of the aquifer, is estimated to total only about 10 percent of annual withdrawals. According to a 2013 report by research hydrologist Leonard F. Konikow at the United States Geological Survey (USGC), the depletion between 2001–2008, inclusive, is about 32 percent of the cumulative depletion during the entire 20th century (Konikow 2013:22)." In the United States, the biggest users of water from aquifers include agricultural irrigation and oil and coal extraction. "Cumulative total groundwater depletion in the United States accelerated in the late 1940s and continued at an almost steady linear rate through the end of the century. In addition to widely recognized environmental consequences, groundwater depletion also adversely impacts the long-term sustainability of groundwater supplies to help meet the Nation’s water needs."
An example of a significant and sustainable carbonate aquifer is the Edwards Aquifer in central Texas. This carbonate aquifer has historically been providing high quality water for nearly 2 million people, and even today, is full because of tremendous recharge from a number of area streams, rivers and lakes. The primary risk to this resource is human development over the recharge areas.
Discontinuous sand bodies at the base of the McMurray Formation in the Athabasca Oil Sands region of northeastern Alberta, Canada, are commonly referred to as the Basal Water Sand (BWS) aquifers. Saturated with water, they are confined beneath impermeable bitumen-saturated sands that are exploited to recover bitumen for synthetic crude oil production. Where they are deep-lying and recharge occurs from underlying Devonian formations they are saline, and where they are shallow and recharged by meteoric water they are non-saline. The BWS typically pose problems for the recovery of bitumen, whether by open-pit mining or by in situ methods such as steam-assisted gravity drainage (SAGD), and in some areas they are targets for waste-water injection.
- Aquifer storage and recovery
- Aquifer properties
- Artesian aquifer
- Groundwater model
- Groundwater pollution
- Hydraulic tomography
- Seasonal thermal energy storage - aquifers may be used for storing heat or cold between opposing seasons and for ecologically heating/cooling greenhouses, buildings, and district systems.
- Surficial aquifer
- "aquitard: Definition from". Answers.com. Archived from the original on 29 September 2010. Retrieved 2010-09-06.
- FMFN (June 2012). Fort McKay’s Review of Teck Resources Ltd. – Frontier Oil Sands Mine Project Integrated Application (PDF) (Report). Fort McKay First Nation.
- Falling Water Tables
- Bibliography on Water Resources and International Law Peace Palace Library
- IGRAC International Groundwater Resources Assessment Centre
- SahysMod aquifer model
In other projects
- This page was last modified on 1 May 2016, at 06:20.