Reservoir

Shopping on line can be easy, simple and save you lots of money. It can also take a lot of your time, frustrate you, and result in unwanted purchases. Now the same can be said for regular high street shopping, but with the vast opportunity presented by the Internet it will pay you to spend a few minutes reading this and understanding how to better optimize your Reservoir shopping experience:

1. Compare - without doubt the biggest advantage that the Reservoir offers shoppers today is the ability to compare thousands of Reservoir at a time. This is a great thing, but not necessarily all the time! Too much can be daunting at times so take advantage of the great comparison sites and where possible let them do the hard work for you.

2. Research - if it has been said it will be on the internet. Ignorance is no longer a justifiable reason for buying the wrong thing. Take the time to research in detail everything that you could possible want to know about

3. Testimonials - don't know anybody that has bought a Reservoir? Wrong! If the Reservoir is good the internet will let you know. Use the Internet as a friend and get testimonials before you buy.

4. Questions - Got a question about Reservoir then search the Forums, FAQ's, Blogs etc. Don't be afraid to ask .....

5. Reputation - Never heard of the company selling Reservoir? Don't worry, no reason why you should know every company in the world, but you know someone that does! Use the internet to find out what people are saying about Reservoir and build up a picture of their reputation for sales, returns, customer service, delivery etc.

6. Returns - still worried that even after all of the above your Reservoir wont be what you want? Check out the returns policy. There is so much competition now that someone, somewhere is bound to offer the terms that you are comfortable with.

7. Feedback - happy with your Reservoir then let people know, after all you are depending on others people input in your buying decision, so why not give a little back.

8. Security - check for the yellow padlock on the Reservoir site before you buy, and the s after http:/ /i.e. https:// = a secure site

9. Contact - got a question about Reservoir, or want to leave a comment then check out the sites contact page. Reputable companies have them and respond.

10. Payment - ready to pay for your Reservoir, then use your credit card or PayPal! Be aware of companies that don't accept them, there may be genuine reasons but given the huge amount of choice you have when buying online there is no reason at all not to buy via credit card or PayPal.

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Most often, a reservoir refers to an artificial lake, used to store water for various uses. Reservoirs are created first by building a sturdy dam, usually out of cement, soil, Rock (geology), or a mixture. Once the dam is completed, a stream is allowed to flow behind it and eventually fill it to capacity. Reservoirs exist in a wide variety of shapes and sizes, and can be either natural or man-made.

Construction reservoir in Switzerland

There are two basic types of reservoir—the commonly seen dam across a valley or the less common fully bunded dam.

A fully water tower bunded dam has a continuous man made embankment around its entire perimeter, most commonly using a central clay core as the waterproof element. The core is held in place by earth or rock piled either side of it in suitable volumes to resist the outward forces exerted by the water. The clay is joined directly to the natural underlying material, which itself is usually clay in order for the dam to be water tight. The reservoir is filled by mechanical pumps that draw water from an adjacent water course such as a river.

If a water tight roof is added then this dam can then be used for storing treated water before it goes to the tap and is known as a "Service" reservoir.

The more common dam across a valley relies on naturally formed features to form the water tight elements. Generally, surveying have to find river valleys which are deep and narrow; the valley sides can then act as natural walls. The best place along the valley for building a dam has to be determined according to where the dam can best be tied into the valley walls and floor to form a water tight seal. If necessary, humans have to be re-housed and/or historic sites have to be moved, e.g. the temples of Abu Simbel before the construction of the Aswan Dam, creating Lake Nasser in the Nile, Egypt.

, the newest of those built at Rivington in Lancashire

First, the river must be redirected slightly so as to not disturb construction of the dam. Once that is done, building of the dam may commence. This may take anywhere from a few months to a few years, depending on its size and complexity. After the dam is complete, the river is allowed to begin filling the large area behind the dam.

Some reservoirs are entirely underground. In the United Kingdom Thames Water has many underground reservoirs beneath London built in the 1800s by the Victorians, most of which are lined with thick layers of brick. Honor Oak Service reservoir, which was completed in 1909, is the largest of this type in Europe. The roof is supported using large brick pillars and arches and the outside surface is used as a golf course.

Operation Standard A raw water reservoir doesn't simply hold water until it is needed. It is the first part of the treatment process. The time the water is held for before it is released is known as the retention time, and is a design feature that allows larger particles and silts to settle out as well as time for the biological treatment of algae and bacteria by plankton-like creatures that naturally live within the water.

Water is then released from the reservoir, generally by gravity, to be cleaned (for drinking water). In the event that major rain occurs, water can be released, decreasing the reservoir's water level.

Hydroelectric A hydroelectricity power station consists of large water turbine that rely on a gravity flow of water through pipes from the dam to turn a turbine to generate electricity. The water can then be either released to the surrounding water course or pumped back into the reservoir and reused. Generally, hydroelectric dams are built specifically for electricity generation and are not used for drinking or irrigation water.

Controlling watercourses Reservoirs can be used in a number of ways to control how water flows through downstream waterways.

Irrigation Water in an irrigation reservoir is released into networks of canals mainly for use in farmlands or secondary water systems. Water in an irrigation reservoir is generally not used for drinking water, but in some cases is. As with all reservoirs, water can be released if the reservoir is too full.

Flood control Commonly known as an "attenuation" or "balancing" reservoir, these are used to prevent flooding to lower lying lands, flood control reservoirs collect water at times of unseasonally high rainfall, then release it slowly over the course of the following weeks or months. See transvasement.

Compensation If a standard reservoir is built on a river which is used as a source of power, a compensation reservoir may also be built to guarantee a sufficient flow of water downstream during the working hours of the water-powered industries.

Canal Where a natural watercourse's water is not available to be diverted into a canal, a reservoir may be built to guarantee the water level in the canal; for example, where a canal climbs to cross a range of hills.

Recreational Very rarely is a reservoir built solely for a recreational purpose. Most reservoirs are built to a civic purpose, but still allow fishing, boating, and other activities. At most reservoirs, special rules apply for the safety of the public.

Largest Lake Volta in western Africa covers around 8,500 km². Lokka in the municipality of Sodankylä in Northern Finland is Northern Europe's largest artificial lake, 417 km² in size. The IJsselmeer is Western Europe's largest artificial lake, 1,250 km² in size.

Surface area The following are the world's ten largest reservoirs by surface area:

Lake Volta (8,482 km²; Ghana)

Smallwood Reservoir (6,527 km²; Canada)

Kuybyshev Reservoir (6,450 km²; Russia)

Lake Kariba (5,580 km²; Zimbabwe, Zambia)

Bukhtarma Reservoir (5,490 km²; Kazakhstan)

Bratsk Reservoir (5,426 km²; Russia)

Lake Nasser (5,248 km²; Egypt, Sudan)

Rybinsk Reservoir (4,580 km²; Russia)

Caniapiscau Reservoir (4,318 km²; Canada)

Lake Guri (4,250 km²; Venezuela)