Man-made lake | Article about Man-made lake by The Free Dictionary Man-made lake | Article about Man-made lake by The Free Dictionary Related to Man-made lake: artificial lake reservoir (rĕz`əvôr, –vwär), storage tank or wholly or partly artificial lake for storing water. Building an embankment or dam dam, barrier, commonly across a watercourse, to hold back water, often forming a reservoir or lake; dams are also sometimes used to control or contain rockslides, mudflows, and the like in regions where these are common. ..... Click the link for more information. to preserve a supply of water for irrigation irrigation, in agriculture, artificial watering of the land. Although used chiefly in regions with annual rainfall of less than 20 in. (51 cm), it is also used in wetter areas to grow certain crops, e.g., rice. ..... Click the link for more information. is an ancient practice; India and Egypt have many old and large reservoirs. In building artificial lakes for a municipal water supply it is necessary to consider all the aspects of a catchment area catchment area or drainage basin, area drained by a stream or other body of water.

The limits of a given catchment area are the heights of land—often called drainage divides, or watersheds—separating it from neighboring drainage systems. ..... Click the link for more information. , including the amount and distribution of rainfall, evaporation, runoff, soil or rock conditions, and elevation (for its effect upon precipitation and upon the pressure in the conducting pipes). The ground of the reservoir may be naturally impervious enough to prevent excessive seepage, or a clay or other lining may have to be built. The embankments or retaining walls may be of earth, loose rock, or masonry. Earth forms a good embankment but must be sealed by a core of clay, and the face must be covered with masonry or a similar substance to prevent erosion. Distributing reservoirs in towns are sometimes built of masonry or of reinforced concrete. They serve to cope with fluctuations of demand and with interruptions of supply from the source. Reservoirs are also built on the headstreams of or along the courses of rivers to aid in flood control, on canals to maintain water level for navigation, and to ensure water supply for hydroelectric plants.

Some reservoirs are built on the tributaries of large rivers to act as catch basins for silt. In addition to seepage, the major loss of water from a reservoir is by evaporation; chemicals that form a film on a water surface are used to minimize such losses. Covered tanks made of prestressed concrete are used for limited local water supply. Reservoir in hydroelectric power engineering. Pressure reservoir of a hydroelectric power plant. A structure that connects the nonpressured water supply of the power plant with the turbine conduits and serves to eliminate litter, sludge, and ice from the flow and also to discharge excess water in case of sudden cutting off of the hydraulic units from the power system. In terms of construction, a pressure reservoir is a part of the channel that is smoothly increasing in plan and elevation, ending in a retaining structure where intake basins for the turbine water pipelines are located. Daily regulation reservoir. The daily regulation reservoir of a hydroelectric power plant is an artificial reservoir that is built at the plant with nonpressured supply to regulate the diurnal water flow required by the station; it is located in the immediate vicinity of the pressure reservoir and is connected to it by a short canal.

Depending on the local conditions, the diurnal regulating reservoir can adjoin the supply or be placed on its route. Reservoirs are built in the form of an excavation in the ground, a partial excavation, or a partial embankment; the perimeter is enclosed by earthen dikes or reinforced-concrete walls. A dip in the local topography is usually utilized in its construction. Equalizing reservoir. The equalizing reservoir of a hydroelectric power plant is an artificial reservoir in the after-bay of the plant that serves to equalize the nonuniform discharges of water (as a result of the diurnal regulation) coming from the turbines. REFERENCES Reservoir an artificial body of water that is formed, as a rule, in a river valley by hydrostatic structures; water is collected and stored in it for use in the national economy. Reservoirs are characterized by increased depth toward the dam, with the exception of those that include deep lakes; extremely slow water exchange and flow velocity compared to rivers; instability of summer thermal and gas stratification; and certain other peculiarities of the hydrological regime. Reservoirs are created to redistribute the flow of rivers with respect to time and, with canals and other water-conveying structures, to area.

They form the base of a comprehensive utilization of water resources. The need for reservoirs is caused by the great unevenness in the distribution of river discharge during the course of the year, as well as its unequal territorial distribution. Reservoirs may have diurnal, weekly, seasonal (or yearly), and even longer periods of regulation. The volume of a reservoir’s water mass—and consequently its surface area, depth, and so on—is subject to seasonal changes associated with the irregularity of the natural water flow, as well as of the consumption of water for the needs of the national economy. Reservoirs are built in widely diverse sizes, ranging from several dozen hectares to several thousand square kilometers in area and from hundreds of thousands of cubic meters to hundreds of cubic kilometers in volume (see Table 1). According to data of the Institute of Water Problems of the Academy of Sciences of the USSR, the total volume of reservoirs in operation or under construction as of Jan. 1, 1971, was approximately 5,000 cu km.

The total usable reservoir volume of the entire world at the beginning of the 1%0’s was 2,050 cu km, including 755 in America, 525 in Asia, 460 in Africa, 280 in Europe, and 30 in Australia (according to calculations made by M. A. Fortunatov). The following levels are distinguished in a reservoir: the normal affluent level (or horizontal affluent level)—the highest affluent level the dam can support over a long period while ensuring the normal operation of all installations; the forced affluent level—the highest level that can be supported for a relatively brief time during the passage of floodwaters, ensuring the maintenance of the installations; and the level of stagnant volume—the minimum allowable level under conditions of normal operation. The creation of reservoirs causes essential changes in the terrain of river valleys, and their regulation of the river’s flow transforms the natural hydrological regime within the back-water. Changes in the hydrological regime caused by the creation of reservoirs also occur in the tail waters of hydraulic-engineering complexes, sometimes for dozens and even hundreds of kilometers.

The decrease in high-water periods, as a result of which the conditions for the spawning of fish and the growth of grasses in the river marshes deteriorate, is of great importance. A decrease in the flow velocity causes the precipitation of alluvium and the silting-up of reservoirs; the temperature and ice cycles change, and in winter a polynya, which is sometimes dozens of kilometers long and which does not freeze over, forms in the tail water. The height of wind waves on reservoirs is higher than on rivers (3 m and more). The hydrobiological regime of reservoirs differs essentially from the regime of rivers; the biomass in a reservoir forms more intensively, and the variety of flora and fauna changes. Floating islands of peat mold ranging from several square meters to hundreds of hectares appear in a number of reservoirs during their first few years of operation. Depending on their configuration, intensity of water exchange, and, consequently, their hydrological regime, reservoirs are divided into lake and river types. Lake reservoirs (for example, Rybinsk) are characterized by the formation of water masses whose physical properties differ essentially from those of the tributary waters. The currents in these reservoirs are primarily governed by the winds.

River reservoirs (Dubossary and others) are smaller; their currents are governed by gravity, and their water masses closely resemble river waters. The creation of a reservoir brings about many changes in the terrain and economy of the surrounding region. There is flooding, partial flooding, and washing out of the lands along the banks, on which fallow and cultivated lands, populated areas, industrial enterprises, and transportation routes were located; economic and transportation links, as well as conditions in public health, hygiene, and the fishing industry, change. The effect of a reservoir on the climate increases with the size of its water mass. Large reservoirs exert a relatively noticeable influence on the climate within a fairly narrow zone (3-10 km wide) along the banks, resulting in less abrupt diurnal and annual temperature variations and increased atmospheric humidity. After 1950 certain regions with well-developed industry Table 1. Largest reservoirs of the world Reservoir - definition of reservoir by The Free Dictionary Reservoir - definition of reservoir by The Free Dictionary (rĕz′ər-vwär′, -vwôr′, -vôr′) n. 1. A natural or artificial pond or lake used for the storage and regulation of water.

2. A receptacle or chamber for storing a fluid. 3. An underground accumulation of petroleum or natural gas. 4. Anatomy See cisterna . 5. A large or extra supply; a reserve: a reservoir of goodwill. 6. Medicine An organism or population that directly or indirectly transmits a pathogen while being virtually immune to its effects. [French réservoir, from réserver, to reserve, from Old French reserver; see reserve.] reservoir (ˈrɛzəˌvwɑː) n 1. (Civil Engineering) a natural or artificial lake or large tank used for collecting and storing water, esp for community water supplies or irrigation 2. a receptacle for storing gas, esp one attached to a stove 3. (Biology) biology a vacuole or cavity in an organism, containing a secretion or some other fluid 4. (Anatomy) anatomy another name for cisterna 5. a place where a great stock of anything is accumulated 6. a large supply of something; reserve: a reservoir of talent.

[C17: from French réservoir, from réserver to reserve] res•er•voir (ˈrɛz ərˌvwɑr, -ˌvwɔr, -ˌvɔr, ˈrɛz ə-) n. 1. a natural or artificial place where water is collected and stored for use, esp. water to supply a community or region. 2. a receptacle or chamber for holding a liquid or fluid. 3. a body of porous, permeable rock in which a pool of oil or gas has accumulated. 4. Anat. a cavity or part that holds some fluid or secretion. 5. a place where anything is collected or accumulated in great amount. 6. a large or extra supply or stock; reserve. [1680–90; < French réservoir=réserv(er) to reserve + -oir -ory 2] res·er·voir (rĕz′ər-vwär′) 1. A natural or artificial pond or lake used for the storage of water. 2. An underground mass of rock or sediment that is porous and permeable enough to allow oil or natural gas to accumulate in it.

Reservoir a store; a collection; a reserve. Examples: reservoir of important facts, 1837; of means, 1784; of nourishment, 1813; of water, 1708. ThesaurusAntonymsRelated WordsSynonymsLegend: Man-made Reservoirs | SSWM Man-made Reservoirs Beat Stauffer (seecon international gmbh), Nina Carle (seecon international gmbh), Dorothee Spuhler (seecon international gmbh) Executive Summary FAO 1992). Water stored in a valley usually has a higher level than the valley bottom downstream of the dam. Because of this difference in level, the valley can be irrigated by a gravity system or other distribution systems. Water can be taken from the of reservoirs is often used to produce electricity (see also hydropower small-scale and hydropower large-scale ). Ecological Impacts Comparison of the riverbed landscape between upstream and downstream reaches of the Yasugawa Dam in the Yasu reservoir in a drainage basin and the abstraction of significant water amounts for storage upstream significantly impacts the watercourse, the flora and fauna, and the human inhabitants in the drainage basin.

These potential impacts should be identified and thoroughly examined prior to ’ (EIA). Such an assessment is now obligatory by law in many countries for all new dam constructions (UNEP 2000). Ecological impacts of river bed degradation and increase in substrate grain size by sediment trapping, etc. (TAKEMON 2006). Furthermore big dams and extraction of water (e.g. for spate irrigation ) can create riparian conflicts (see water conflicts ). Also read the paragraph “Impact on Environment” in the rivers factsheet. Basic Design Principles ’ includes several types of constructed water-bodies and/or water storage facilities: 1. Valley reservoirs – created by constructing a barrier (dam) perpendicular to a flowing river . 2. Off- river . The latter reservoirs are sometimes called embankment or bounded reservoirs, and have controlled inflows and outflows to and from one or more , and inter-basin transfer schemes – designed to move water through a series of reservoirs, tunnels and/or canals from one drainage basin to another. Pumping from a Reservoir for Irrigation Adapted from is sealed with an impermeable liner. Source: B.

STAUFFER (2009) The fields located around the is only possible with the help of pumping stations , manual or motorised pumping . The water level in the reservoir . The branch is filled with water during the wet season and closed off during the dry season so that the stored water may be used. Due to the low water level, pumps are normally needed to irrigate fields from such a . Costs Especially for large reservoirs costs are high. It must be designed by engineers and heavy machinery is necessary. Furthermore, costs for material as well as . This must be planned carefully as it directly impacts the environment as described above. Also read the document “Reservoir Operations and Managed Flows” (WMO and GWP 2008). Dams, especially the very large ones, must be checked regularly to ensure their stability and security. Furthermore, many man-made water reservoirs are affected by high that provides irrigation , power generation (see small scale and large scale hydropower ), flood control , and recreational use may cause conflicting demands by its users (WATERENCYCLOPEDIA 2011).

Health Aspects Faecal pollution and other contamination of reservoirs has to be prevented by wastewater treatment and buffer zones in case of non-point sources of pollution (see also the factsheets on lakes or invalid link). If the , impacts (ecological, riparian) must be considered to avoid contamination, damage of the environment or user conflicts . Advantages Quick and easy access to a water source Creation of drinking water and water for other uses Increased protection of downstream river from flooding events Increased potential for sustained agricultural irrigation Production of energy (hydropower) Storage of water for use during low-flow periods Increased fishery possibilities Depending on its size it can become an important economic factor for a region (drinking water, recreation, etc.) Disadvantages Excessive human immigration into reservoir region, with associated social, economic and health problems Displacement of local populations following inundation of reservoir water basin Displacement of local populations following inundation of reservoir water basin Riparian conflicts can occur especially in arid areas Dams are expensive in construction and maintenance References UNEP (Editor) (2000): Lakes and Reservoirs: Similarities, Differences and Importance . Osaka: United Nations Environment Programme (UNEP IETC).

URL [Accessed: 17.01.2012]. WATERENCYCLOPEDIA (Editor) (2011): Reservoirs, Multipurpose . Illinois: Advameg Inc. URL [Accessed: 03.11.2011]. WMO (Editor); GWP (Editor) (2008): Reservoir Operations and Managed Flows. A Tool for Integrated Flood Management . Geneva and Stockholm: World Meteorological Organization (WMO) and Global Water Partnership (GWP). URL [Accessed: 30.04.2012]. PDF Further Readings ACREMAN, M. (2000): Managed Flood Releases from Reservoirs: Issues and Guidance . Wallingford: Centre for Ecology and Hydrology. URL [Accessed: 17.01.2012]. PDF In this report, a managed flood is a controlled release of water from a reservoir to inundate a specific area of floodplain. This document focuses on developing countries but most issues are relevant world-wide. ARAOYE, P.A.

(2002): Man-Made Lakes, Ecological Studies and Conservation Needs in Nigeria . Ilorin: University of Ilorin. PDF The benefit derived from the creation of man-made lakes in Nigeria and other developing countries is usually associated with great risks. Whenever we establish a dam, it appears we dam the inherent consequences to the detriment of man and his environment. FAO (Editor) (1992): Irrigation Water Management: Training Manual No. 6 - Scheme Irrigation Water Needs and Supply . Rome: Food and Agriculture Organization (FAO). URL [Accessed: 13.12.2011]. This training material gives an introduction to crop water needs and discusses the influence of climate, crop type and growth stage. It also discusses how much of the crop water need can be met by rainfall and/or irrigation applications. Further, it introduces the special requirements of growing rice. Finally, it looks at the irrigation water needs within a parcel of land at the plant level. SHARIP, Z.; ZAKARIA, S. (2008): Lakes and Reservoirs in Malaysia: Management and Challenges . URL [Accessed: 17.01.2012].

PDF This paper looks into various studies on the status of lakes and reservoirs that have been carried out in Malaysia. It details out some of the major issues and problems faced in the areas of lake research, management, governance, capacity building, information management and stakeholder participation. The paper concludes with strategies and plans to consider as the way forward to overcome the issues. TAKEMON, Y. (2006): Ecological Impacts of Reservoir Dams on River Ecosystems in Tail Waters . Singapore: Asia Oceania Geosciences Society (AOGS). URL [Accessed: 30.04.2012]. PDF In this lecture, impacts of reservoir dams such as decreasing flow volumes in tail waters or barrier for animalsare reviewed with some examples inJapanese and Asian rivers, particularly those on benthic animals and their habitatconditions in tail waters. How Lakes Differ - Lake Scientist How Lakes Differ Susanna Scott | Miami University Lakes vs. Ponds Both lakes and ponds are standing or slow-moving bodies of water. There are no official or scientific differences between lakes and ponds. Lakes are larger than ponds, but size is relative.

What would be considered a pond in one region might be considered a lake in another. In general, water bodies that are considered lakes in dry areas would only be considered ponds in regions with abundant water resources where there are more (and larger) bodies of water. Despite the lack of official characteristics, there are several questions that are used to generally distinguish ponds from lakes: Does light reach the bottom of the deepest point of the water body? Does the water body only get small waves (i.e., smaller than 1ft/30cm in height)? Is the water body relatively uniform in temperature? If these questions can be answered with a “yes,” the water body is likely a pond and not a lake.1 Although vernal pools dry up regularly, they are important sites for breeding and feeding for many organisms (Image from 4). Ponds are often overlooked as habitats and sources of biodiversity, but they play many important roles in the landscape. Many types of organisms spend at least part of their life in pond habitats, which function as important breeding grounds. Amphibians spend their juvenile stages in ponds, as do many insects. Some ponds, like vernal pools (Figure 1) are temporary and only filled with water for part of the year.

However, theses pools are still teeming with life and are inhabited by organisms such as faerie shrimp, salamanders, and wood frog tadpoles while they are inundated with water. Ponds also function as important stopover spots for migrating birds. These spots provide places to rest, as well as a source of food for migrating waterfowl.2 Ponds also provide many uses for society. They are used for agricultural irrigation, nutrient and sediment retention, recreation, livestock, fish, wildlife protection and production, and aesthetic appeal. Threats to pond quality include, nutrient loading, pollution, acid rain and invasive species.3 Lakes vs. Rivers Lakes and ponds are standing bodies of water while rivers and streams are distinguished by a fast-moving current. While there appear to be clear distinctions, the differences become subtle in regions where rivers widen and current slows such that the river could be considered a lake or a pond. Additionally, rivers may occasionally form lakes such as oxbow lakes when portions of a river become geologically separated from the main flow path over time. River systems make up about 0.0001% of the Earth’s water.

While this may not seem like much, rivers drain more than 75% of the Earth’s surface. Rain and other types of precipitation move water overland, through terrestrial ecosystems and into river systems. The resulting runoff brings inputs of sediments, nutrients, and materials into the river, causing running waters to be highly influenced by their surrounding landscapes. The flow of river systems carries the sediments, nutrients, and other materials through the landscape and into other systems, providing vital linkages between the land, lakes, wetlands and oceans. It is because of this that rivers are often referred to as the environment’s circulatory system.5 Lakes vs. Reservoirs Reservoirs, also called impoundments, are man-made lakes. Often, reservoirs can be thought of as a combination of lakes and rivers because they were created by building a dam and flooding a river valley. This damming and flooding creates an artificial lake, filled by the river inflow, with the same qualities of rivers and lakes. The upstream section of the reservoir has predominantly river-like qualities, meaning there is often still some current, and the organisms in this section are usually those found in rivers.

As the water moves closer to the dam, the current slows, and the reservoir becomes more lake-like. At this point, many of the sediments and materials carried by the river settle to the bottom of the reservoir. Many of the organisms inhabiting this region of the reservoir are those more typically found in lakes. However, some reservoirs maintain river-like qualities throughout. The degree to which riverine properties dominate the reservoirs is often a function of the size of the impounded river and the amount of time water spends in the reservoir (termed residence time). Reservoirs with a short residence time are more river-like while reservoirs with a long residence time are more like natural lakes. Reservoirs are built for many uses. Some are built strictly for recreation (such as fishing and boating) or to control floods. Others are built to store water that may be used for drinking water and irrigation. Finally, hydroelectric dams use the flow of water over turbines to generate electricity. 6 Freshwater vs. Saline Lakes People are most familiar with freshwater lakes. Chances are the lake closest to you is a freshwater lake. But some lakes are extremely salty. These are called saline lakes.

Although freshwater lakes often have minor amounts of dissolved salts in them (less than 1-3 g/L), saline lakes have more than this (between 3 and 300g/L). 7 Saline lakes are often found in arid environments where water only leaves lakes through evaporation or seepage into the ground. This evaporation concentrates salts and other chemicals in the water over time. Endorheic lakes are found throughout the globe; major basins are shown in grey above and the largest endorheic lakes are shown in black. (Image from 10). Although many freshwater lakes and rivers drain into the ocean, saline lakes are formed when they are the endpoint to river flow. These lakes are known as endorheic (which means terminal), and are sometimes referred to as inland seas.8 Endorheic lakes usually form because they are at the lowest point in the landscape and are found in basins throughout the world. Well-known endorheic lakes include the Dead Sea (Israel/Jordan), the Great Salt Lake (Utah), Mono Lake (California) and the Caspian Sea (Eurasia).

Mono Lake, an endorheic lake in California, is extremely salty because water only leaves the lake through evaporation or seepage. Evaporation concentrates salts, and other chemicals such as arsenic, in the lake over time. Saline lakes such as the Great Salt Lake in Utah provide important habitat for many kinds of organisms. Some saline lakes are too salty to support anything but algae, but lakes such as the Great Salt Lake are habitats for crustaceans including brine shrimp. The shores and waters of these lakes also provide valuable habitat and breeding territory for birds such as shore birds and waterfowl.9 Inland seas are an important source for mineral trade and often have a great cultural significance. These lakes however are very sensitive to changes in climate. Because of high rates of evaporation in the areas they are located, even small reductions in precipitation can drastically reduce their size. With the reduction in size due to decreased inputs of freshwaters, salinity concentrations increase, which can change the biota and lead to decreased biodiversity. 5 Sources: Dams and Reservoirs - An Overview Dams and Reservoirs Sign Up for Our Free Newsletters Thanks, You're in!

What I Learned About Today You might also enjoy: Health Tip of the Day Recipe of the Day There was an error. Please try again. Please select a newsletter. Please enter a valid email address. Did you mean ? Study and Teach Geography Glen Canyon Dam on the Colorado River in Arizona. Bruce Heinemann/Getty Images A dam is any barrier that holds back water; dams are primarily used to save, manage, and/or prevent the flow of excess water into specific regions. In addition, some dams are used to generate hydropower. This article examines man-made dams but dams can also be created by natural causes like mass wasting events or even animals like the beaver. Another term often used when discussing dams is reservoir. A reservoir is a man-made lake that is primarily used for storing water. They can also be defined as the specific bodies of water formed by the construction of a dam. For example, the Hetch Hetchy Reservoir in California’s Yosemite National Park is the body of water created and held back by the O’Shaughnessy Dam. continue reading below our video 4 Tips for Improving Test Performance Types of Dams Today, there are several different types of dams and the man-made ones are classified by their size and structure.

Typically a large dam is classified as being higher than 50-65 feet (15-20 meters) while major dams are those over 492-820 feet (150-250 meters). One of the most common types of major dams is the arch dam. These masonry or concrete dams are ideal for narrow and/or rocky locations because their curved shape easily holds back water via gravity without the need for a lot of construction materials. Arch dams can have one large single arch or they can have multiple small arches separated by concrete buttresses. The Hoover Dam which is on the border of the U.S. states of Arizona and Nevada is an arch dam. Another type of dam is the buttress dam. These can have multiple arches, but unlike a traditional arch dam, they can be flat as well. Normally buttress dams are made of concrete and feature a series braces called buttresses along the downstream side of the dam to prevent the natural flow of water. The Daniel-Johnson Dam in Quebec, Canada is a multiple arch buttress dam. In the U.S., the most common type of dam is the embankment dam.

These are large dams made out of soil and rock which use their weight to hold back water. To prevent water from moving through them, embankment dams also have a thick waterproof core. The Tarbela Dam in Pakistan is the world’s largest embankment dam. Finally, gravity dams are huge dams that are constructed to hold back water using only their own weight. To do this, they are constructed using extensive amounts of concrete, making them difficult and expensive to build. The Grand Coulee Dam in the U.S. state of Washington is a gravity dam. Types of Reservoirs and Construction Like dams, there are different types of reservoirs as well but they are classified based on their use. The three types are called: a valley dammed reservoir, a bank-side reservoir, and a service reservoir. Bank-side reservoirs are those formed when water is taken from an existing stream or river and stored in a nearby reservoir. Service reservoirs are mainly constructed to store water for later use. They often appear as water towers and other elevated structures. The first and usually largest type of reservoir is called a valley dammed reservoir.

These are reservoirs that are located in narrow valley areas where tremendous amounts of water can be held in by the valley’s sides and a dam. The best location for a dam in these types of reservoirs is where it can be built into the valley wall most effectively to form a water tight seal. To construct a valley dammed reservoir, the river must be diverted, usually through a tunnel, at the start of work. The first step in creating this type of reservoir is the pouring of a strong foundation for the dam, after which construction on the dam itself can begin. These steps can take months to years to complete, depending on the size and complexity of the project. Once finished, the diversion is removed and the river is able to flow freely toward the dam until it gradually fills the reservoir. Dam Controversy In addition to the high cost of construction and river diversion, dams and reservoirs are often controversial projects because of their social and environmental impacts. Dams themselves affect many different ecological components of rivers such as fish migrations, erosion, changes in water temperature and therefore changes in oxygen levels, creating inhospitable environments for many species.

In addition, the creation of a reservoir requires the flooding of large areas of land, at the expense of the natural environment and sometimes villages, towns and small cities. The construction of China’s Three Gorges Dam , for example, required the relocation of over one million people and flooded many different archaeological and cultural sites. Main Uses of Dams and Reservoirs Despite their controversy, dams and reservoirs serve a number of different functions but one of the largest is to maintain an area’s water supply. Many of the world’s largest urban areas are supplied with water from rivers that are blocked via dams. San Francisco, California for example, gets the majority of its water supply from the Hetch Hetchy Reservoir via the Hetch Hetchy Aqueduct running from Yosemite to the San Francisco Bay Area. Another major use of dams is power generation as hydroelectric power is one of the world’s major sources of electricity. Hydropower is generated when the potential energy of the water on the dam drives a water turbine which in then turns a generator and creates electricity. To best make use of the water’s power, a common type of hydroelectric dam uses reservoirs with different levels to adjust the amount of energy generated as it is needed.

When demand is low for instance, water is held in an upper reservoir and as demand increases, the water is released into a lower reservoir where it spins a turbine. Some other important uses of dams and reservoirs include a stabilization of water flow and irrigation, flood prevention, water diversion and recreation. To learn more about dams and reservoirs visit PBS's Dams Site . Prev Freshwater - The Water Cycle, from USGS Water-Science School View full size As this picture of the Nile Delta in Egypt shows, life can even bloom in the desert if there is a supply of surface water (or groundwater) available. Water on the land surface really does sustain life, and this is as true today as it was millions of years ago. I'm sure dinosaurs held their meetings at the local watering hole 100 million years ago, just as antelopes in Africa do today. And, since groundwater is supplied by the downward percolation of surface water, even aquifers are happy for water on the Earth's surface. You might think that fish living in the saline oceans aren't affected by freshwater, but, without freshwater to replenish the oceans they would eventually evaporate and become too saline for even the fish to survive.

As we said, everybody and every living thing congregates and lives where they can gain access to water, especially freshwater. Just ask the 6 billion people living on Earth! Here's a satellite picture of the Mediterranean region during night (the full picture of the Earth is available from NASA). The most obvious thing you can see is that people live near the coasts, which, of course, is where water, albeit saline, is located. But the interesting thing in this picture are the lights following the Nile River and Nile Delta in Egypt ( the circled area). In this dry part of the world, surface-water supplies are essential for human communities. And if you check the price of lakefront property in your part of the world, it probably sells for much more than other land. Usable fresh surface water is relatively scarce To many people, streams and lakes are the most visible part of the water cycle. Not only do they supply the human population, animals, and plants with the freshwater they need to survive, but they are great places for people to have fun. You might be surprised at how little of Earth's water supply is stored as freshwater on the land surface, as shown in the diagram and table below.

Freshwater represents only about three percent of all water on Earth and freshwater lakes and swamps account for a mere 0.29 percent of the Earth's freshwater. Twenty percent of all fresh surface water is in one lake, Lake Baikal in Asia. Another twenty percent (about 5,500 cubic miles (about 23,000 cubic kilometers)) is stored in the Great Lakes. Rivers hold only about 0.006 percent of total freshwater reserves. You can see that life on Earth survives on what is essentially only a "drop in the bucket" of Earth's total water supply! People have built systems, such as large reservoirs and small water towers (like this one in South Carolina, created to blend in with the peach trees surrounding it) to store water for when they need it. These systems allow people to live in places where nature doesn't always supply enough water or where water is not available at the time of year it is needed. Source: Gleick, P. H., 1996: Water resources. In Encyclopedia of Climate and Weather, ed. by S. H. Schneider, Oxford University Press, New York, vol.

2, pp.817-823. One estimate of global fresh-water distribution Water source Water volume, in cubic miles Water volume, in cubic kilometers Percent of Lakes and Reservoirs, USGS Water Science School View full size If people had to pick their favorite water body, they might choose a crystal-clear lake nestled in the mountains (my opinion, or course!). Not all lakes are clear or are near mountains, though. The world is full of lakes of all types and sizes. A lake really is just another component of Earth's surface water . A lake is where surface-water runoff (and maybe some groundwater seepage) have accumulated in a low spot, relative to the surrounding countryside. It's not that the water that forms lakes get trapped, but that the water entering a lake comes in faster than it can escape, either via outflow in a river, seepage into the ground, or by evaporation . And if humans live nearby, then water levels can be affected by water withdrawals for human needs. A reservoir is the same thing as a lake in many peoples' minds. But, in fact, a reservoir is a manmade lake that is created when a dam is built on a river.

River water backs up behind the dam creating a reservoir. Here's a question for you: when a beaver dams a creek, is the pond that it creates a lake or a reservoir? Lakes come in many varieties The Earth has a tremendous variety of freshwater lakes, from fishing ponds to Lake Baikal in Siberia. Lake Baikal is the world's oldest, largest, and deepest freshwater lake. Nearly a mile deep and holding over 23,000 cubic kilometers water, it would require the total volume of all the Great Lakes to fill it up if it were ever drained ( NASA ). Most lakes contain fresh water, but some, especially those where water cannot escape via a river, can be classified as saline lakes . In fact, some lakes, such as the Great Salt Lake in Utah, are saltier than the oceans. Most lakes support a lot of aquatic life, but not all. The Dead Sea in the Middle East isn't called "Dead" for nothing —it is too salty for aquatic life! Lakes formed by the erosive force of ancient glaciers , such as the Great Lakes, can be thousands of feet deep.

Some very large lakes may be only a few dozen feet deep—Lake Pontchartrain in Louisiana has a maximum depth of only about 15 feet. Some of the salty lakes were formed in ancient times when they were connected to seas and when rainfall may have been heavier. These lakes have been shrinking since the last ice age. The ancient Lake Bonneville in the United States was once as big as Lake Michigan, and the Great Salt Lake was once about 14 times larger than it is now. People use (and abuse) lakes Greenlake Lake in Seattle, Washington. Urban lakes are highly valued by local residents for recreation (and for high property values of houses along the shoreline!). Credit: Howard Perlman, USGS Lakes are highly valued for their recreational, aesthetic, scenic, and water-supply qualities, and the water they contain is one of the most treasured of our natural resources. Lakes constitute important habitats and food resources for a diverse array of fish, aquatic life, and wildlife. But lake ecosystems are fragile. Lake ecosystems can undergo rapid environmental changes, often leading to significant declines in their aesthetic, recreational, and aquatic ecosystem functions.

Exposed to external effects from the atmosphere, their watersheds , and groundwater, lakes are subject to change through time. Human activities can further accelerate the rates of change. If the causes of the changes are known, however, human intervention (lake-management practices) sometimes can control, or even reverse, detrimental changes. Urban lakes, like this one in Seattle, Washington, are highly valued by local residents. Where urban lakes exist, you'll find lots of walkers and joggers, people enjoying canoeing and swimming, picnickers, and, of course, lots of dogs and ducks. The water can sometimes be used for water supply for a city's needs, also. Urban lakes do have special needs, though. Water quality must be monitored constantly; it would not be good for the mayor of a town to become ill from swimming in polluted water. The inflow of nutrients, such as phosphorus and nitrogen from fertilizers, must be restricted in order to prevent the overgrowth of algae. And, where there is wildlife, such as ducks, around, there is the chance of bacteria problems. Characteristics of lakes The following are some of the most important basic factors that give unique character to each lake ecosystem.

Climate: Temperature, wind, precipitation , and solar radiation all critically affect the lake's hydrologic and chemical characteristics, and indirectly affect the composition of the biological community. Precipitation is the main factor affecting runoff and the delivery of nutrients and sediments. Atmospheric inputs: Precipitation, such as acid rain , and dry particles can be major sources of certain contaminants to a lake. Each lake also receives indirect atmospheric inputs by way of the runoff from its watershed. Underground rock and soils in the watershed: The soil type affects the potential for runoff and erosion. The physical characteristics of the underground rock determine the extent, nature, and quality of groundwater inflows and outflows. Physiography: The area, surface topography, existence of upstream lakes and wetlands, altitude, and land slope of the lake's watershed affect surface-water runoff and the amount and nature of chemicals and sediments entering the lake. Interactions with land use by people can greatly change how these factors affect runoff and the export of nutrients and sediment.

Land use: The type, location, extent, and history of land cover/land use (such as agriculture, rural, and urban developed areas) can greatly affect the quantity of surface-water and groundwater inflows and outflows, as well as the amounts and types of sediment, nutrients and chemicals (natural or synthetic) that are transported into the lake from the watershed. Lake morphometry: Size, shape, and depth characteristics of a lake are critical in determining currents and mixing of the lake, as well as its thermal and chemical stratification characteristics. Common environmental problems in lakes and probable causes Lakes are subject to a variety of problems that can diminish their aesthetic beauty, recreational value, water quality, and habitat suitability. Among the most common lake problems is eutrophication, which is the process of physical, chemical, and biological changes ("aging") associated with nutrient, organic matter, and silt enrichment of a lake. Eutrophic conditions can be exhibited with the following conditions: Algal blooms Extensive and rapid growth of planktonic (floating and suspended) algae, caused by an increased input of nutrients (primarily phosphorus , but sometimes nitrogen ), is a common problem in lakes.

Lakes normally undergo aging over centuries, but the process can be accelerated rapidly by human activities that cause increases in sedimentation and nutrient inflow to the lake. Accelerated eutrophication and excessive algal growth reduces water clarity, inhibits growth of other plants, and can lead to extensive oxygen depletion, accumulation of unsightly and decaying organic matter, unpleasant odors, and fish kills. Sedimentation/ turbidity Increases of sediments can harm water quality and the habitat for many aquatic species. Such events usually are caused by heavy rains that produce erosion and intense runoff. Oxygen depletion Decreases in dissolved oxygen to less than 3 mg/L (milligrams per liter) in the water can be harmful or lethal to aquatic life. Oxygen can get used up due to organic decomposition. Prolonged low oxygen concentrations can lead to fish kills. Growth of aquatic plants Normal plant growth generally is beneficial for the lake ecosystem; among other benefits, the plants provide refuge for fish and other organisms. However, in some lakes, the growth of aquatic plants ("weeds") can become excessive and create a serious nuisance for lake users, interfering with swimming, boating, and other recreational activities.

Other causes of excessive plant growth include increased nutrients in the water, invasion of exotic species, and accumulation of organic sediment. Water-level changes Wide fluctuations in stage (lake level) can create major hardships for lakeside residences, marinas, and businesses. These changes most commonly are linked to weather anomalies (extended periods of abnormally high or low precipitation), but also may be associated with human activities such as withdrawals for water use. Species shifts Populations of desirable animal and plant species might decline sharply or disappear, to be replaced by other less-desirable species. Species shifts can be caused by introduction of invasive species that may have little or no natural controls on their population growth. OFFICIAL SITE of Lake Arrowhead California - History Page Prev Next Lake Arrowhead - In The 'Alps' Of Southern California Nestled in the magnificent San Bernardino National Forest, surrounded by pine, cedar, and dogwood, at an altitude of 5100', an area described as the "Alps of Southern California", and known as "the best kept secret on the West Coast, is a stunningly beautiful, cozy and quaint mountain resort paradise called Lake Arrowhead.

Our community features countless outdoor recreational activities such as hiking, backpacking, camping, bicycling, lake tours, water and snow skiing, ice skating, fishing, horseback riding, and much more. With the stunning scenery and wildlife, comes a natural peacefulness that has lured people to these mountains for centuries. Lake Arrowhead offers 5 Star resort hotel accomodations and restaurants, seasonal weather, and exceptional real estate opportunities. Whether you're looking for rest, relaxation, a romantic getaway from "the flatlands", or the thrill of being at one with Mother Nature and all she has to offer, you're sure to find it here at the lake, so plan your visit soon!. The Early Beginnings... The first white man ever to set foot in Little Bear Valley (now known as Lake Arrowhead) was a fur trader, who was a partner of Jedediah Smith, in 1826. At that time, about 40 Paiute Indians, a warlike tribe, used the mountains for their hunting grounds. They lived in the high desert area. Many were finally killed in a fight with the white men of Little Bear Valley, resulting from the Indians setting fire to one of the white men's cabins.

At the same time, a more peaceful tribe of Indians, the Serranos, lived very near Bear Valley, in an area now known as Rock Camp, on the north side of the mountain. They did not bother the settlers until one of the white men made advances to an Indian maiden, which caused a skirmish killing both Indians and white men. The Serrano Indians lived in the San Bernardino mountain range occupying Little Bear Valley. They would take thier old and sick to Arrowhead Hot Springs for rejuvenation and healing. They hunted in the beautiful and bountiful valley and lived relatively peaceful, somewhat nomadic lives descending to the desert highlands and warmer inland valleys during the winter months. The first so-called "Mormon Road" up the mountain was built in 1852. In the 1860's, the main attraction for the white man at Little Bear Valley was logging, lumber and cattle, and there were several saw mills in and around the Valley. White man in the Little Bear Valley was first interested in the lumber. The trees were tall and straight and cut lumber could be hauled down to San Bernardino on a road constructed through the west end of the range.

The "Daley Canyon Road" was built in 1870. Summers were productive in the Valley, but everything stopped in the winter. A few families remained during the winter months and their only diversion was to snow shoe to their neighbors (usually miles away) to visit. In the early 1890's Little Bear Valley was chosen as a location for a reservoir. The dam would supply water to the lowlands in the San Bernardino Valley. Work on the reservoir started in 1893. Camp I in the north end of the valley was built to house the workers. The land at what would be the bottom of the lake was cleared to prevent decay from becoming a problem and fouling the water. The dam, a semi-hydraulic fill dam was to be 200 feet high, 720 feet wide, and 1,100 feet thick at the base. In 1912 the dam was 80% complete. Work continued several more years, but legal problems rendered the dam's diversion of water illegal. The lake behind the dam had partially filled with water, however the project was abandoned.

The Company was stopped from continuing with its plan to transport water to the areas south of the mountains, and even though the lake was filling with water. In 1891, three Ohio businessmen chose Little Bear Valley as a likely spot for a reservoir, to supply water to the southern lowlands. Land was purchased and water rights were obtained. The Arrowhead Reservoir Company was formed. In 1890, a tramway, (a cable powered device) was built from Waterman Canyon up the mountain for the purpose of transporting supplies for the building of the dam. However, engineering problems rendered it unsuccessful. Consequently, supplies and machinery were transported via the switchback road. Construction of the dam for the reservoir started in 1893. "Camp 1" on the north slope of the valley served as living quarters and messhalls for the workers. In 1905, the property was transferred to a new corporation -- Arrowhead Reservoir and Power Company -- because the idea of utilizing the water for power had been conceived.

The dam is what is known as a semi-hydraulic, fill dam, 200 feet high, 720 feet long and 1,100 feet thick at the base. It has a steel reinforced concrete core wall, embedded 20 feet in bed rock. The trees and brush were removed from what was to be the bottom of the lake, so that decay would not be a problem. The lake filled slowly from runoff. By 1912, the dam was 80% complete, and work continued for several years after that. The plans called for over 60 miles of water conveyances and tunnels. However, only 6 1/2 miles of tunnels were completed, when it became known that the State ruled in favor of the ranchers on the upper desert side of the mountains, who relied on the water from the northward facing watershed, and passed laws which prevented the diverting of water from its natural watersheds for other than domestic use.

The Arrowhead Lake Company, a Los Angeles syndicate, bought Little Bear Lake and surrounding land (approximately 4,800 acres) in 1920, and changed the name to Lake Arrowhead, (deriving the name from the rock formation in the form of an Arrowhead on the face of the San Bernardino Mountain, near Arrowhead Hot Springs, which is rooted in Indian legend). Their plan was to develop the valley and lake behind the dam into a resort community. By 1923 the dam was completed and a road built along part of the north shore. A Norman style village complete with pavillion, outdoor movie theatre, restaurant and beach were constructed. Three hotels were built: the Arlington Lodge, Village Inn and North Shore Tavern as well as the 9 hole golf course. Some of the lakeside land was subdivided and sold for private homes and secluded north shore estates. Many Hollywood stars stayed at the hotels during that era, and some purchased homes in the resort. The studios frequently used the area for locations for making films. A domestic water system, pumping water from deep in the lake, supplied the homes, and the structures were connected to a vey efficient sewer system.

Strict restrictions and conditions affecting the use of land and the buildings erected in Arrowhead Woods were recorded with each tract, including the removal of trees. During the war years, Lake Arrowhead Village was a popular rest and recuperation area for service men. Because of gas rationing, tourists were scarce. In spite of lot sales, financial troubles developed and the Arrowhead Lake Company went into receivership. In 1946, the Los Angeles Turf Club (owners of Santa Anita Race Track) purchased the lake and surrounding properties, know as Arrowhead Woods. Several million dollars were spent by the Turf Club, within the first few years of their ownership, in improving the properties. There were no lots sold to speak of during the Turf Club ownership, however they made several donations of land to various organizations, such as the Boy Scouts, Girl Scouts, San Bernardino County, churches, Sisters of St. Joseph of Orange, (the builders of the hospital), and they also donated $50,000 toward the construction of the hospital. The famous North Shore Tavern was donated to the University of California and is now a popular conference center. Renovation...

In 1960, the Lake Arrowhead Development Company was formed by three developers from Los Angeles. They built the present day 18 hole golf course and club house over the old 9 hole course and subdivided 18 residential tracts. In 1967 the Lake Arrowhead Development Company merged with the Boise Cascade Corporation and additional subdivision of properties were created. In 1971, Lake Arrowhead was purchased by seven businessmen from Chicago. In 1973, Boise Cascade was forced to re-acquire Lake Arrowhead through foreclosure. The Chicago group retained some of the properties not mortgaged by Boise, including some unsubdivided acreage. At the time Boise re-acquired the property, they were faced with the problem of building a new dam or lowering the lake 70 feet, due to a study required by the State to be made of all dams in California following the Van Norman Dam incident in the 1971 Sylmar earthquake. The study found Arrowhead dam would probably be unsafe if an earhtquake of 6.5 magnitude were to occur in this area.

However, Boise felt that the building of a dam should be shared by all property owners in Arrowhead Woods, and legislation was passed to permit a bond issue to be voted on by property owners to finance the building of a new dam downstream. A bond for seven million dollars was passed in 1974 and a new earthfill dam was built. A small lake was formed between the two dams, named by a local resident -- "Papoose Lake." The property owners in Arrowhead Woods bought Lake Arrowhead in October, 1975 from Boise, and Boise sold their remaining holdings in Lake Arrowhead to Metropolitan Advertising Agency in 1977. In 1978, a group of investors, headed by developer George Coult, bought the Village and Lodge properties. In April of 1979, the Burn To Learn exercise was conducted by the Lake Arrowhead Fire Protection District with the San Bernardino County Fire Departments and the Air Corps taking part. All structures in the Village were burned except the original dance pavilion building, the post office, bank and real estate office.

Lake Arrowhead Village The beautiful new Village was built in much the same architecture as the old Village, and the dance pavilion was restored as the Theme building, which now houses the Papagayos Restaurant. Lake Arrowhead Village is the area's main commercial hot spot for both visitors and locals. With a variety of unique fashion boutiques, outlet stores, restaurants, and a supermarket, The Village provides excellent shopping and dining before heading back to your cozy lodging. Also home to a FREE SUMMER CONCERT SERIES on CENTER STAGE, from May through September, Lake Arrowhead Village entertains thousands at more than forty free concerts each Friday and Saturday night and on holidays, throughout the summer. The Village includes a complete convenience shopping center providing many professional services, and offers many culinary delights, from lake view restaurants and caf�s to ice cream and chocolate confections. Shopping possibilities are varied and rich, with factory outlets, galleries, boutiques, gift and specialty shops. Attractions include Family Go-Carts on the beach, McKenzie Ski School, the oldest continually operating ski school in the country, a playground with play stations for ages 5-12, and spectacular lake tours on the Arrowhead Queen, a stately 60-seat paddlewheeler.

The Village celebrates many special events throughout the year- Easter, the 4th of July, Oktoberfest and Christmas, to name a few, and enjoys live music and activities throughout the Village on most weekends. Lake Arrowhead is not only a popular recreational area for visitors, it is also a beautiful year round Alpine residential community at 5000 feet elevation. Come up and enjoy the seasons, the fresh mountain air and beautiful vistas that are Lake Arrowhead... Lake Arrowhead TODAY Four Beautiful Seasons One of the most prized assets of the area is that it truly experiences four distinct seasons. Our weather offers residents and visitors alike the opportunity to enjoy a wide variety of outdoor activities. SPRING in Lake Arrowhead brings mild temperatures and bright colors as the area bursts with life. Blooms flower, wildlife babies emerge from their winter hideaways, and the sounds of chirping birds fill the Lake Arrowhead air, as people visit for a romantic get away from Los Angeles, Orange County, and from faraway places. Hiking is a popular spring activity here. There are many hiking trails, with a favorite being the Pacific Coast Trail, located about seven miles away from the Lake, and running from the Mexico border to Canada.

Anglers everywhere know that spring is the best time of the year to land a big fish, which brings pros and novices alike to Lake Arrowhead lodging establishments. Whether you're looking to snag a big one or just want to enjoy the experience with a little catch and release, you can cast your jig or bait in the lake or in nearby public Lake Gregory for Bass, Carp, Catfish, Crappie, Kokanee Salmon, Sunfish, and Trout. SUMMER in Lake Arrowhead is warm and cozy, without being hot and humid, and the air is CLEAN!! The gentle breeze from the lake provides just the right amount of cool during this time of year when water sports are at their most exciting and sunbathing is at its most relaxing. Swimming, water skiing, boating, dock parties, fishing, hiking, bicycling, horseback riding, and more take place during the summer on our lake and in our beach clubs. Those visiting Lake Arrowhead resort properties can make full use of this beautiful private lake and anyone staying at a Lake Arrowhead lodging can take part in water activities at nearby Lake Gregory.

And, don't forget that Lake Arrowhead is home to a FREE SUMMER CONCERT SERIES on CENTER STAGE, from May through September, Lake Arrowhead Village entertains thousands at more than forty free concerts each Friday and Saturday night and on holidays, throughout the summer. When visiting during the summer, remember to take the Lake Arrowhead Queen Paddleboat Tour, which lasts about an hour and takes you around the perimeter of Lake Arrowhead. The notoriously hilarious tour guide has a great reputation for his jokes and one-liners and always has the entire boat in stitches as he points out celebrity homes and tells stories and fun facts about the area. For example, did you know that there have been 120 movies filmed in Lake Arrowhead, including Heidi, The American President, Space Jam, Next, and the 1998 remake of The Parent Trap? FALL in Lake Arrowhead brings out the red, gold, and orange colors of the mountains, and provides the perfect backdrop for camping in Lake Arrowhead. One of the most popular campgrounds is the North Shore Campground. Only three miles from The Village, this beautiful campground features modern Lake Arrowhead lodging amenities for campers, like running water and restrooms.

San Bernardino National Forest also provides outdoor activities in the forest with equestrian trails and trails for mountain biking and off road vehicles. With cool evenings and warm days, fall is glorious in Lake Arrowhead!! WINTER brings fluffy white snow that transforms Lake Arrowhead into an unbelievably beautiful, peaceful winter wonderland. No traffic, crystal clear skys, perfect quiet... Skiing and snowboarding are favorite winter activities at our mountain ski resorts, Snow Valley, Bear Mountain, and Snow Summit. The Big Bear Ranger Station and Discovery Center hosts a snowshoe tour, and several groups offer guided winter hikes, and you can ice skate at one of the world's most beautiful outdoor skating rinks. Plenty More To Do In Lake Arrowhead While outdoor activities abound, there is still plenty to do in Lake Arrowhead if you're not an outdoor person at heart. The area is teeming with shopping, dining, culture, cozy Lake Arrowhead lodging, Lake Arrowhead resort spas, and fun events that boost the reputation of the area as a perfect family vacation spot. The Annual Lake Arrowhead Home Tour takes participants on a tour of some of the most remarkable homes in the community.

Whether a historic log cabin with a significant story to tell, or a modern and high tech lakefront mansion, this tour can provide you with a look at the finest architecture and d�cor Lake Arrowhead has to offer. The Lake Arrowhead Yacht Club, which began operations in 1932 in Lake Arrowhead, has over 350 members and a fleet of over 35 sailboats and The Annual Antique and Classic Wooden Boat Show features historic wooden boats from manufacturers of the past. Lake Arrowhead is home to the Ice Castle International Training Center, an Olympic training facility for figure skaters, and The University of California Los Angeles (UCLA), operates the UCLA Conference Center near Lake Arrowhead, a full service conference facility with excellent lodging and plenty of meeting space. Plan Your Visit To Lake Arrowhead As a romantic get away from Los Angeles, Orange County, or anywhere else for that matter, Lake Arrowhead's community has a strong sense of local pride. The economy is mostly dependent on tourism, including lodging, dining, resorts and spas. The primary tourism industries include real estate, lodging, dining, skiing, recreation, resorts, spas, and retail sales..

Whether you're looking for a romantic get away, a relaxing family escape, or a thrilling outdoor adventure, Lake Arrowhead offers a perfect destination for individuals, couples, families, groups of all sizes.

Question: What is a man made lake for storing water called
Answer: A reservoir