Should You Test Your Well?

Editor’s Note:  The article below is adapted from a 2013 Water Technology article by Jake Mastroianni. — Hardly Waite.

Pure Water Annie’s FAQ Series

Pure Water Gazette Technical Wizard Pure Water Annie Answers All the Persistent Questions about Water Treatment.

This week’s topic: Faucet Diverter Valves.

 What are diverter valves used for?

The main use in water treatment is to change the direction of flowing water–to send a water stream a in a different direction for a purpose.  The most common usage is with countertop water filters, where the valve is used to divert the stream of water flowing into the sink so that it flows instead through the water filter.

The countertop filter sits beside the sink and gets its water from the diverter valve attached to the sink faucet.  It’s circled in the picture.

Are there different kinds of valves?

Yes, the most standard is the type that diverts water running from the sink faucet through a single tube to the water filter. Another style, called a “return” diverter, diverts water to the filter, then dispenses the filtered water that has been returned to the valve through a separate tube. With the standard diverter water is dispensed through a spout on the water filter itself.  With the return style, a double hose assembly is needed, but there is no dispensing spout.

Standard diverter valve.  Tube that sends water to the filter is attached with the compression fitting on the right. (Cheaper valves often use “barbed” connectors to which the tube is pushed on.)  Pulling the knob on the left sends water to the water filter and the knob springs back to “off” position when the sink water is turned off.

“Return” diverter valve sends water to the filter exactly like the standard model, but filtered water is returned through a second hose to the small spout attached to the side of the valve.  The return hose attaches to the barbed connector in the picture.

What causes diverter valves to fail?

The most usual cause is calcium scale buid-up on the spring and other inner parts.

How do you fix a diverter valve if the knob sticks open and the spring fails to turn it off?

Suggested methods (sometimes they work, sometimes they don’t) include soaking the entire valve in a weak acid like vinegar to dissolve the calcium buid-up on the spring, using a chemical descaler like LimeOut, or removing the valve from the sink faucet and dropping a couple of drops of vegetable oil into the small hole in the top of the valve where water enters the valve from the faucet. One of the best ways is to simply ignore the problem.  You’ll find that manually turning off the water with a push of the finger really isn’t a big deal. Or, you can replace the valve with another like it (Pure Water Products offers lifetime parts replacement on its countertop filters), or, you can replace the standard valve with a springless model that requires pushing for both on and off, as we’ve always done with light switches.  A springless, toggle-style diverter is shown below.

This diverter has no spring, and if you’re up to this much exercise, you can push the plunger one way to turn the valve on and then push from the other side to turn it off.

Which is better, the “compression” diverter valves pictured on this page or the conventional diverters that are attached with a barbed fitting and in some models even clamped on with a machine so they can’t be removed?

Since this is a part that, no matter how good it is, almost never lasts as long as the rest of the water filter, it’s obvious that being able to replace it easily is a big advantage.  With some countertops, the entire hose assembly has to be changed in order to replace the diverter valve.

I tried but can’t put the hose on a new barbed style diverter that I bought.  How do you do it?

The best way is to soak the tubing in fairly warm water for a few minutes.  This will usually expand the tubing and allow you to push it onto the barb.  When it cools,  the barb will hold it tight.

Other topics covered by Pure Water Annie’s FAQ Series.

Drought-hit Pakistan turns to solar water treatment

By Saleem Shaikh and Sughra Tunio

Pure Water Annie’s FAQ Series.

Pure Water Gazette Technical Wizard Pure Water Annie Answers All the Persistent Questions about Water Treatment.

This week’s topic: Air Gap Faucets.

I’m buying a new undersink water filter.  Should I get an air gap faucet with it or a standard faucet?

Standard.  Air gap faucets are used only with reverse osmosis units.

Why don’t they use them with filters?

Filters don’t have a drain line.  The air gap faucet is mainly about the drain.  The “air gap” for the drain is put in the faucet only because that’s a convenient place to locate it. The purpose of the air gap is to prevent backflow from the drain to the RO unit.

Why does the air gap faucet need three tubes instead of one?

See the illustration below.  The tube on the left, the one that enters the threaded stem,  carries the drinking water to the spout.  The other two tubes carry the RO unit’s reject water to drain.  The small tube carries the it from the RO unit up to the body of the faucet and the larger tube carries it down the to the drain saddle attached to the home’s drain pipe.  The “air gap” occurs between the two tubes.  The two drain tubes are not connected inside the faucet base.  There’s an “air gap” between them that prevents backflow from the drain to the RO unit.

What’s the purpose of the hole in the faucet body under the handle?

The hole, indicated by the arrow in the picture above,  is a drain hole.  If the home’s drain is stopped up so that water can’t exit via the large drain tube on the faucet, the drain water simply backs up and dumps out of the faucet and (usually) onto the sink top. This is one of the reasons that people often curse air gap faucets.

How do I fix the problem if water drains onto my sink top?

You have to unstop the undersink drain pipe.  Sometimes it’s only a small obstruction in the large faucet drain tube itself.  In that case, you can usually fix the problem by removing the 3/8″ (larger) tube from the drain saddle and clearing it.  Blowing through the tube often clears it.

Is the gurgling sound I hear when the RO unit runs caused by the air gap faucet?

Usually, yes, but any RO drain can be noisy.  Another cause of noisy drains is an improperly placed drain saddle.

Can I replace the air gap faucet with a standard faucet?

Yes, but  you’ll have to re-route your drain water.  You don’t really have to replace the faucet itself. Simply re-routing the the drain water will get rid of noise and drain water on the countertop.  There’s an easy way to use a simple adapter to replace the air gap feature of the faucet with a check valve (one way valve) that will keep water from backing up into the RO unit from a stopped up drain pipe.  The check valve may or may not satisfy your local plumbing code but it’s a safe way to keep drain water from backing up into your RO unit.

The red tube carries drain water from the RO unit up to the air gap.  The black tube carries the drain water back down to the drain pipe. (Click picture for a larger view.)

What size hole do I need to install an air gap faucet?

Standard faucets need only a 7/16″ hole in the countertop, but the air gap needs at least a 3/4″ hole because of the extra tubes and the spacer (the white object in the picture).

Do new reverse osmosis units come with an air gap faucet?  

Some do, some don’t. Some offer options.  Pure Water Products’ Black and White RO units, for example, come standard with a non-air gap faucet but with a high quality check valve installed in the drain line. The air gap faucet is available for the asking at no additional charge.

More about air gap faucets, including installation instructions.

Filter Carbon

Carbon, sometimes called “charcoal,” is the most universally applied of all water treatment filter media. Residential water filters, from the common end-of-faucet taste enhancers to elaborate whole house systems, almost always are carbon filters or use filter carbon as one of their principal ingredients.

Filter carbon is a manufactured product, made commonly from coal, woods, and nut shells.  Not all filter carbon is the same.  It varies depending on the raw material and manufacturing techniques applied. Performance depends on the pore size of the carbon as well as the format produced by manufacturing.  It can be used in granular form (similar to coffee grounds), powder, or tight, molded blocks. It can even be stuck to the surface of other filtering devices like pleated filters or combined in beds with other media like KDF.

Carbon made with bituminous coal is the most common and most universally used.  It has average pore size, containing large and small pores, and is therefore useful in most filtering applications.  Carbon will smaller pores–coconut shell carbon is the most popular–is best at dealing with contaminants like VOCs that require lots of small pores. Large pore carbon, typically made from wood or lignite coal, is best at removing colors from water.

Carbon reduces contaminants either by catalytic action, physical straining, or adsorption.  For example, it acts as a catalyst to convert chlorine to harmless chloride or to break down chloramine to chlorine and ammonia.  Although all carbon can perform this function, specially prepared carbon called “catalytic carbon” can do it much faster. Catalytic carbon can also be used to reduce hydrogen sulfide odors or to remove iron from well water.  Most chemical reduction is done by adsorption, with the contaminant becoming trapped on the craggy surface of the carbon. Although this isn’t it’s best function, carbon can also be used to physically trap particles in granular beds or in carbon block form.  Very tight carbon blocks can screen out things as small as bacteria or cysts.

In addition to removing chemicals, which is carbon’s main function, it almost always improves the taste, odor, and appearance of water.

Pure Water Annie’s FAQ Series.

Pure Water Gazette Technical Wizard Pure Water Annie Answers All the Persistent Questions about Water Treatment.

 Aer-Max aeration systems, for treatment of iron and hydrogen sulfide.

How does Aer-Max work?

Aer-Max works by providing a pocket of compressed air in the top third of a closed tank. When water containing hard-to-treat contaminants like iron, manganese, and hydrogen sulfide falls through the air pocket, the contaminants are oxidized so they can be easily removed by a filter. The compressed air is supplied by a small air pump.  A vent is provided to keep the air pocket fresh.  The Aer-Max system is not a filter.  It prepares contaminants for easy removal by a filter that follows the aeration tank.

There are 110-volt and 220-volt systems.  Which is better?

The voltage needed depends mainly on how the unit is to be controlled. The pump and vent can be turned off and on by having them wired directly into the electrical circuit that turns the well pump off and on.  Since most well pumps run on 220 volt current, if you choose this method of control it’s easiest to use a 220-volt Aer-Max.  If you use an alternative control system, like a flow switch or a simple timer, however, you would want the 110-volt system.

Which is the best way to control the system?

For residential use, the flow switch is the last choice.  It turns the Aer-Max unit on when water flows through the pipe toward the home.  Usually this results in frequent and short on/off cycles and is the least efficient way to operate the system.  The conventional method is to bring 220-volt electrical receptacles for the air pump and the vent solenoid out of the pressure switch that controls the well pump.  With this system, the AerMax is activated when the well pump runs and turns off when the well pump is not running. This is a proven system and it works well.  Use of a simple timer, the kind used to turn lamps off and on at specified times, is becoming the most popular,  however.  It’s easiest to install: you just plug the pump and vent solenoid into the timer and plug the timer into a wall receptacle.

Standard Aer-Max System

But doesn’t the air pump have to be running while water is going through the treatment tank?

This is probably the biggest source of misunderstanding about how Aer-Max works.  The rich pocket of compressed air in the top of the treatment tank needs only to be refreshed from time to time: effective treatment does not depend on fresh air entering while water is running through the tank.  With hydrogen sulfide, for example, while a small amount of the offensive gas may be vented out of the tank by the drain system, treatment consists mainly of reducing the odor-causing gas to elemental sulfur so that it can be removed by the filter that follows the air treatment tank. Residential users who control the unit with timers usually run the air pump only about three times a week.  This vents the tank and refreshes the air pocket.  Unless you run large amounts of water, three times a week is enough.

What is the function of the three tubes attached to the aeration head in the illustration above?  

From left, the first, the shortest, is a baffling device. It creates turbulence to enhance aeration as water entering the tank falls through the air pocket. The middle tube is the vent tube.  It maintains the level of the air pocket in the tank.  The long tube is the pickup tube for treated water being sent to the home.

What kind of filter has to be used after the Aer-Max?

Aer-Max enhances the performance of any standard iron filter medium.  It works especially well with Birm, Filox, and Katalox Light.  Media like Zeolite (Turbidex) and Filter Ag can be used as iron filters if the water is pre-treated with Aer-Max, and an especially effective treatment for both iron and low pH can be accomplished by using a backwashing calcite filter after Aer-Max.  For large amounts of iron it’s best to use the best–Filox or Katalox Light.  Both media will treat both iron and hydrogen sulfide after aeration.

Both Filox and Katalox Light work well with both hydrogen sulfide and iron.  If hydrogen sulfide is present, Birm is not a good choice.

For hydrogen sulfide, catalytic carbon is the best available, but standard carbon also works well. Actually, any granular filter medium will remove odor after AerMax, but carbon is best. If no iron or manganese is present, a cartridge style carbon filter (4.5″ X 20″ preferred) can be used to treat hydrogen sulfide odor, but a cartridge filter will stop up quickly if there’s iron in the water.  With iron and manganese, a backwashing filter is required.

Standard Air Pump Used for Aer-Max

I’m using a water softener to remove iron, but it isn’t quite doing the job.  Can I install an Aer-Max unit in front of it to improve its performance?

No. The Aer-Max will actually interfere with the softener’s ability to remove iron by turning the ferrous iron to ferric.  Filters catch ferric iron easily, but a softener is an ion exchanger, not a filter.  If your water is hard and has iron, either remove both with the softener or use both filter and softener. The correct order of treatment if aeration is used is Aer-Max,  iron filter, then softener.

How loud is the pump?

Approximately 50 decibels.

How long does the pump last, and does it need regular maintenance?

The pump usually runs 20,000 to 25,000 hours before bearings need replacement. It’s an easy pump to work on, and parts are available. The most common maintenance issue is cleaning.  Although the pump has an air filter, in some environments it will need an occasional cleaning (see instructions).

Which works best — Aer-Max or the newer style single tank aeration/filtration systems that are becoming popular?

Aer-Max and the newer single tank units, which have the filter and the aeration treatment in the same tank, work on exactly the same principle but there are some significant differences. In general, the Aer-Max is more robust and will handle higher contaminant levels and higher flow rates. It can also be used to pre-treat for multiple filters. Single-tank setups, which use a venturi draw rather than an air pump, are more compact (one tank  rather than two), easier to install, and less expensive to purchase.  Once installed, both systems are low maintenance unless high levels of iron are involved.  Any equipment removing iron will eventually need some cleaning. The Aer-Max plus filter arrangement is definitely preferred over single tank units for large amounts of iron or hydrogen sulfide–over 8 parts per million of either.

Does the Aer-Max have to be vented outdoors when treating hydrogen sulfide because of the odor?

Odor isn’t an issue, but water is.  The 3/8″ drain tube will vent both air and water when when the vent valve is open, so it needs to be connected to a suitable drain.  It is often teed into the drain tube or pipe that serves the backwashing filter, but it can simply be allowed to drain onto a lawn or water a shrub. The drain water isn’t toxic.

Is there only one size Aer-Max system?

No, there is a high capacity pump available and it can be used with larger aeration tanks to create high flow systems. The higher capacity pump is usually preferred on “constant pressure” wells, where a higher air pressure needs to be maintained in the treatment tank. The 10″ X 54″ treatment tank, with the standard air pump, works in almost all residential applications, so it the the system most frequently sold. See high capacity systems here.

Will Your Water Filter Protect You if  You Have a Boil Water Alert?

Adapted from an email communication by Marianne Metzger of National Testing Laboratories.

With the cold weather comes the increased possibility of water mains and pipes bursting.  Pipes and mains are at risk in colder weather due to the expansion and contraction of the pipe material.  Even a 10° change in temperature of air or water can cause significant stress on the pipes. Other factors like the material the pipe is made of, corrosion, soil conditions age. and ground movement also contribute to breaks.

There are approximately 250,000 water main breaks every year in the United States. That’s 685 breaks per day.

Water customers in the area of the break may experience a shut off of water while repairs are being made. Additionally, if customers do have access to water, they may be under a boil advisory.

For those with water treatment equipment this can be confusing. Many people assume that their water treatment device will take care of the problem and they can simply ignore the boil water alert. If an ultraviolet light is part of the equipment, they are right. However, homeowners with other types of treatment equipment cannot simply ignore the alert and they may even may be faced with additional maintenance. It is good practice to change out any carbon-based cartridge filter after a boil advisory because carbon can provide the optimum environmental for any bacteria that may be present as a result of the break. This applies to undersink filters and reverse osmosis units. Whole house carbon filters are also at risk of becoming growing beds for bacteria. For water softeners, it is a good rule of thumb to disinfect the system according to the manufacturer’s instructions after any boil advisory to ensure bacteria are not present.

If  you have doubts about the state of your water filter after a boil water advisory, a simple test for bacteria is a good idea. Bacteria tests can be arrange through most city water departments and through independent agencies that do water testing.

Providing clean water to the developing world

Household water treatment offers the best hope for nearly 900 million people.

by Michael D. Robeson

Many Americans take clean drinking water for granted. However, much of the developing world is still grappling with the challenges of supplying water that is safe for human consumption. The problem affects nearly 900 million people around the globe and leads to 2.2 million deaths by waterborne diseases annually. More than half of the victims are under the age of six.

While the danger in urban areas stems from aging or inadequate water treatment infrastructure, the risk is most acute in rural communities lacking the density or the resources to build and support water treatment facilities.

Many rural residents still fetch water from rivers, lakes, ponds and streams contaminated with human and animal waste, whether from open defecation or factors such as seepage from septic tanks and pit latrines. Even people with access to cleaner water from common wells, collected rainwater or centralized taps face the risk of pollution by an unsanitary container or improper storage in the home.

For these reasons, groups such as UNICEF and the World Health Organization (WHO) have long recognized that the most practical immediate strategy for improving rural drinking water quality is to provide solutions for treating and safely storing water at the household level.

The upshot has been the development of a variety of household water treatment and safe storage (HWTS) technologies designed to improve water quality at the point-of-use (POU), as well as the publication of WHO specifications for evaluating the microbiological performance of different HWTS systems in 2011. That 2011 WHO document was the first to establish target performance levels for bacteria, virus and protozoa in POU water treatment, providing a benchmark for measuring the relative effectiveness of each technology option.

From chlorination to filtration

One common POU solution involves chlorination — essentially the same treatment used to disinfect public water supplies in the early 1900s. The most widely adopted model in this scenario was developed by the Centers for Disease Control and Prevention (CDC) and the Pan American Health Organization in response to a 1990s cholera epidemic in South America. Under this model, diluted sodium hypochlorite is manufactured locally, bottled and added to water by the capful for disinfection. Users agitate the water and wait 30 minutes before drinking.

Benefits of this approach include low cost per treatment and proven reduction of most bacteria and viruses. Drawbacks include relatively low protection against parasites such as Cryptosporidium, potentially objectionable taste and odor, lower effectiveness in turbid waters and the need for a reliable supply chain as well as the financial resources to continually replenish the chlorine-bleach solution.

An alternative household water treatment is solar disinfection. Initiated by the Swiss Federal Institute for Environmental Science and Technology in 1991, this strategy requires users to fill plastic soda bottles with low-turbidity water, shake them for oxygenation and place them on a roof or rack for six hours in sunny weather or two days in cloudy conditions. Ultraviolet (UV) light from the sun works in conjunction with increased temperature to improve water quality.

The pros include ease of use, virtually no cost and effective pathogen reduction. The cons include the need to pretreat even slightly turbid water, long treatment times, especially in cloudy weather, the need for a large supply of clean bottles and the limited volume of water that can be treated at one time.

Most other POU options involve some form of filtration designed to remove pathogens by passing water through porous stones and a variety of other natural materials.

Multiple filter varieties

Clay-based ceramic filters, for example, remove bacteria through micropores in the clay and other materials such as sawdust or wheat flour that are added to improve porosity. The best-known design in this category is a flowerpot-shaped device by the nonprofit organization Potters for Peace that holds eight to 10 liters of water and sits inside a 20- to 30-liter plastic or ceramic receptacle, which stores the filtered water. Some ceramic filters are also coated with colloidal silver to ensure complete bacteria removal and prevent growth of the bacteria within the filter itself.

Slow sand filters, on the other hand, remove pathogens and suspended solids through layers of sand and gravel. One common household biosand filter consists of a concrete container incorporating layers of large gravel, small gravel and clean medium-grade sand. Prior to use, users fill the filter with water every day for two to three weeks until a bioactive layer resembling dirt grows on the surface of the sand. Microorganisms in the bioactive layer consume disease-causing viruses, bacteria and parasites, while the sand traps organic matter and particles.

As with chlorination and solar disinfection, both varieties have virtues as well as limitations. Ceramic filters are effective against bacteria and protozoa but not as effective against viruses, are breakable, typically last only two years, require as often as weekly cleaning and have a flow rate of only one to three liters of water per hour. Slow sand filters have a flow rate of 30 liters of water per hour — enough to suit a family’s needs — but again, lack adequate virus reduction abilities, are costly and difficult to transport at 170 lbs. and require periodic agitation and regrowth of the biolayer that can reduce filter efficiency if done improperly.

Both ceramic and slow sand filters also lack residual protection for filtered water, such as that provided by chlorine, raising the risk of recontamination unless a disinfectant is added after treatment.

A third option is a hybrid of the ceramic and sand designs. This approach utilizes porous ceramic particles blended with silver, zinc and copper, and deploys them in a layered configuration similar to slow sand filtration solutions. The filter is delivered in a barrel-shaped device with a strainer that filters out large debris, a ceramic/metal layer that neutralizes harmful microorganisms through an ion exchange process made possible by the unique properties of the clay itself and a built-in storage chamber for up to 18 liters of clean water.

Advantages consist of validated effectiveness in bacteria, protozoa and virus disinfection including industry-first compliance with WHO’s new household water treatment specifications, ion-based residual disinfection that keeps filtered water safe, minimal maintenance and a 10-year lifespan with no added costs for post-filtering chemical treatment or filtration media replacement, keeping costs low over the life of the filter. Downsides include a higher initial cost compared to other products and difficulty in outsourcing fabrication to developing world factories because the unique filtration materials are not locally available.

Implementation challenges

While household water treatment technologies for developing countries are not new, adoption still falls woefully short of need. According to the CDC, over two million people in 28 developing countries now use solar disinfection for daily drinking water treatment; however, that pales in comparison to the 900 million people who lack access to safe drinking water. Likewise, Potters for Peace has distributed over 200,000 ceramic filters in Cambodia and many more in other countries, but this only scratches the surface of a public health problem killing the equivalent of the entire population of Houston every year.

One stumbling block is the need to work through disparate non-retail channels to reach communities in need. Partnerships must be created with different nongovernmental agencies (NGOs) and multiple local organizations in each country. Finding willing partners is difficult, as is developing sustainable financial models for projects requiring donor funding and subsidies.

Therefore, distribution strategies vary widely. In the case of chlorination, implementations range from a faith-based group in northern Haiti making and bottling its own hypochlorite solution to a large-scale program in which NGO Population Services International both promotes and distributes its own product on a country-by-country basis through local channels such as community health workers and private pharmacies. In the case of ceramic filters, Potters for Peace helps local communities set up filter-making factories that in turn sell their products to NGOs. Each solution and supplier must forge its own path.

Equally challenging is the need to select the most appropriate treatment method for a community’s specific circumstances. Variables such as existing water and sanitation conditions, water quality, cultural acceptability, implementation feasibility and availability of a supply chain for refills or replacement parts will affect the decision. In addition, any implementation must include an education component to teach the use of each technology as well as proper sanitation, food and water handling.

Nevertheless, household water treatment holds the potential to save millions of lives. Until universal access to piped treated water is available, if ever, these decentralized technologies and the small-scale humanitarian models required to deploy them are the best hope for reducing the disease and death toll related to dirty water. Creative solutions, entrepreneurship and new business models will be needed to remove distribution obstacles, provide government funding or microfinancing and bring relief to millions of people who put their lives in danger simply by taking a drink.

Source: Water Technology.

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Think of our water supply as a giant milkshake

by Hardly Waite

Think of our water supply as a giant milkshake, and think of each demand for water as a straw in the glass. Most states permit a limitless number of straws—and that has to change.

You may receive a water bill every month, but you’re not actually paying for water. You’re paying for the cost of service, and this free-rider problem is contributing to the worsening water crisis that threatens to dehydrate the US.

Last year, metro Atlanta—home to 5 million people—came within 90 days of watching its principal water reserves dry up, and one Tennessee hamlet ran out of water entirely. Small towns in Texas and California ran completely out of water in 2014. More than 30 states are now fighting with their neighbors over water, and a surging US population means increasingly less to go around. Proposed solutions range from the expensive (desalination of ocean water) to the just plain unpopular (reuse of municipal waste).

Some may find the idea of charging for water itself immoral, as water authority Robert Glennon counters, “Precisely because water is a public—and exhaustible—resource, the government has an obligation to manage it wisely.”

All Lakes Are Not Alike

by Kacy Ewing and Gene Franks

Lakes have always been a source of awe and mystery for human beings. Their formation can be just as amazing and mysterious.

The definition of a lake is any body of water that is not an ocean, that is of reasonable size, and that impounds water with little or no horizontal movement. There are a great variety of lake sizes and types. On one hand, you have pools that are slightly larger than ponds. The line between a pond and a lake is hazy and subjective. Where I come from, the body of water that Thoreau called Walden Pond would definitely be called a lake.  On the other hand, you have giant lakes such as Lake Superior which contains enough water to submerge all of North and South America under a foot of water. All lakes, large or small, are part of the diverse ecosystem known as a lentic (Latin for sluggish) habitat. Probably even Thoreau didn’t know that.

Much of what causes lake formation is due to the work of glaciers. Glacial activity caused the creation of most of the natural lakes in the world. The process of glaciers scraping over time creates depressions that hold surface water, forming lakes. In mountain regions a cirque lake can form if glacial debris block the upper reaches of a mountain valley and then fill with water. Cirque lakes (from the French word for circus, named because of their concave amphitheater shape) are common to many mountain ranges in the United States and Canada including most ranges of Colorado, Wyoming, Montana, Alberta, and British Columbia.

A Cirque Lake

While glacial activity is responsible for many lakes, lakes form in dry climates due to changes in precipitation during seasonal climate changes. Pluvial lakes are formed in this manner. These lakes, however, have long since disappeared through evaporation.  They are also referred to as paleolakes.

A Pluvial Lake in the Mojave Desert

In addition to climate changes and glaciers, some lakes were formed by extraterrestrial forces. Almost eerie in its perfection, Lake Chubb (now called the Pingualuk lake) in Quebec is a perfectly shaped circle that occupies a meteorite crater that is 1.4 billion years old. At 876 feet (267 meters) deep it is one of the deepest lakes in North America. It is also one of the most transparent lakes in the world with objects used to measure water transparency visible more than 115 feet (35 meters) deep. There is a similar meteor crater near Flagstaff Arizona formed about 50,000 years ago that contained a much smaller, but similarly shaped pluvial lake.

Lake Chubb

While these two lakes were created by forces out of this world, Kettle lakes are created by what lies beneath the earth’s surface. They are depressions formed by stranded blocks of buried glacial ice that slowly melted during the Pleistocene epoch. As they melted the land surface above them collapsed and created a hole. If the collapse created a hole large enough to reach groundwater, a lake was formed. Kettle lakes are found generally in Ohio, Minnesota, North Dakota, Wisconsin, Michigan, Alaska, Colorado, Idaho, Pennsylvania, British Columbia, Manitoba, Ontario, Saskatchewan, Quebec, and central and northern Europe. Most lakes in Michigan, in fact, could be described as kettle lakes.

Kettle Lake

The age of a lake can have a great impact on its characteristics. Lakes can be young, middle-aged, or old. Young lakes are known as oligotrophic lakes, and have bottoms that are very clean and lacking in organic material. A clean lake may sound pristine, but lacking this material means the lake also lacks a sufficient food source to provide appropriate habitat to produce plants and freshwater organisms. Over time, however, earthen particles and other organic materials from decaying plants and animals can build layers of materials making the lake a suitable home for plants and animals.

Middle aged lakes that have allowed for aquatic growth are referred to as mesotrophic lakes. When a lake ages, the amount of organic material and mineral deposits may become excessive and actually inhibit or stop the growth of aquatic plants and animals. An old lake of this type is called an eutrophic lake and is typically filled with an excess of organic and mineral materials.

In addition to all the naturally formed lake varieties, humans have formed many lakes as well. A reservoir is a human-made feature created by construction of a dam or dike. These man-made lakes are created for a variety of reasons including hydroelectricity, direct water supply, and of course, recreation. Salty or fresh lakes are some of the only freely available water sources on land. Mysterious and majestic, they are an important part of human and animal life.

Hoover Dam Created Lake Mead, a Man-Made Lake or Reservoir

Reference: Thomas V. Cech, Principles of Water Resources and the Wikipedia.