There are 3,820 lakes in New Zealand that have a surface area larger than one hectare. Many of the lakes in the central North Island are volcanic crater lakes. The majority of the lakes near the Southern Alps were carved by glaciers. Artificial lakes created as hydroelectric reservoirs are common in South Canterbury, Central Otago and along the Waikato River. [1]
There are:
A trophic level index is used as a measure of the pollution levels of lakes in New Zealand.
Based on the monitoring of 134 lakes it is estimated that one third of New Zealand lakes have high nutrient levels or have poor water quality. [2]
Lake Balkhash is a lake in southeastern Kazakhstan, one of the largest lakes in Asia and the 15th largest in the world. It is located in the eastern part of Central Asia and sits in the Balkhash-Alakol Basin, an endorheic (closed) basin. The basin drains seven rivers, the primary of which is the Ili, bringing most of the riparian inflow; others, such as the Karatal, bring surface and subsurface flow. The Ili is fed by precipitation, largely vernal snowmelt, from the mountains of China's Xinjiang region.
Bassenthwaite Lake is a body of water in the Lake District in North West England, near the town of Keswick. It has an area of 5.3 km2 (2.0 sq mi), making the fourth largest of the lakes in the region. The lake has a length of approximately 4 miles (6.4 km) long and maximum width of 0.75 miles (1 km), a maximum depth of 19 m (62 ft), and a surface elevation of 68 m (223 ft) above sea level. Its primary inflow and outflow is the River Derwent, which drains into the Irish Sea at Workington. The lake is in the unitary authority of Cumberland, and the ceremonial county of Cumbria.
The River Poulter which rises near Scarcliffe in Derbyshire, England is a tributary river of the River Idle in Nottinghamshire. It supplied power to mills along its route, most of which are now gone, although their mill ponds remain. Cuckney mill building is used as a primary school. The river has been dammed to create several lakes in the Dukeries estates of Welbeck Abbey and Clumber House now the National Trust property of Clumber Park. The ornamental Gouldsmeadow Lake, Shrubbery Lake and Great Lake on the Welbeck estate are supplied by a tributary of the Poulter, while Carburton Forge Dam and Carburton Dam were built to power a forge and a mill. Clumber Lake, consisting of an upper and lower lake, which is spanned by a Grade II* listed ornamental bridge, is part of the Clumber estate, and has suffered from subsidence.
Lake Waikare is the largest of several shallow lakes in the upper floodplain of the Waikato River in New Zealand's North Island. It is a riverine lake, located to the east of Te Kauwhata and 40 kilometres north of Hamilton. It covers 34 km2 (13 sq mi).
New Melones Dam is an earth and rock filled embankment dam on the Stanislaus River, about 5 miles (8.0 km) west of Jamestown, California, United States, on the border of Calaveras County and Tuolumne County. The water impounded by the 625-foot-tall (191 m) dam forms New Melones Lake, California's fourth-largest reservoir, in the foothills of the Sierra Nevada east of the San Joaquin Valley. The dam serves mainly for irrigation water supply, and also provides hydropower generation, flood control, and recreation benefits.
A reservoir is an enlarged lake behind a dam. Such a dam may be either artificial, usually built to store fresh water, or it may be a natural formation.
Water aeration is the process of increasing or maintaining the oxygen saturation of water in both natural and artificial environments. Aeration techniques are commonly used in pond, lake, and reservoir management to address low oxygen levels or algal blooms.
Lake Qaraoun is an artificial lake or reservoir located in the southern region of the Beqaa Valley, Lebanon. It was created near Qaraoun village in 1959 by building a 61 m-high (200 ft) concrete-faced rockfill dam in the middle reaches of the Litani River. The reservoir has been used for hydropower generation, domestic water supply, and for irrigation of 27,500 ha.
The Trophic State Index (TSI) is a classification system designed to rate water bodies based on the amount of biological productivity they sustain. Although the term "trophic index" is commonly applied to lakes, any surface water body may be indexed.
Dystrophic lakes, also known as humic lakes, are lakes that contain high amounts of humic substances and organic acids. The presence of these substances causes the water to be brown in colour and have a generally low pH of around 4.0-6.0. Due to these acidic conditions, there is little biodiversity able to survive, consisting mostly of algae, phytoplankton, picoplankton, and bacteria. Ample research has been performed on the many dystrophic lakes located in Eastern Poland, but dystrophic lakes can be found in many areas of the world.
Water resources management is a significant challenge for Mexico. The country has in place a system of water resources management that includes both central (federal) and decentralized institutions. Furthermore, water management is imposing a heavy cost to the economy.
Water pollution in New Zealand is an increasing concern for those who use and care for waterways and for New Zealand regulatory bodies. An increase in population is linked to an increase in water pollution, due to a range of causes such as rural land use, industrial use and urban development. Fresh water quality is under pressure from agriculture, hydropower, urban development, pest invasions and climate change. While pollution from point sources has been reduced, diffuse pollution such as nutrients, pathogens and sediments development and from stormwater in towns is not under control. There are more than 800 water quality monitoring sites around New Zealand that are regularly sampled.
The trophic level index (TLI) is used in New Zealand as a measure of nutrient status of lakes. It is similar to the trophic state index but was proposed as alternative that suited New Zealand.
Costa Rica is divided into three major drainage basins encompassing 34 watersheds with numerous rivers and tributaries, one major lake used for hydroelectric generation, and two major aquifers that serve to store 90% of the municipal, industrial, and agricultural water supply needs of Costa Rica. Agriculture is the largest water user demanding around 53% of total supplies while the sector contributes 6.5% to the Costa Rica GDP. About a fifth of land under cultivation is being irrigated by surface water. Hydroelectric power generation makes up a significant portion of electricity usage in Costa Rica and much of this comes from the Arenal dam.
Water resources management in Nicaragua is carried out by the National water utility and regulated by the Nicaraguan Institute of water. Nicaragua has ample water supplies in rivers, groundwater, lagoons, and significant rainfall. Distribution of rainfall is uneven though with more rain falling on an annual basis in the Caribbean lowlands and much lower amounts falling in the inland areas. Significant water resources management challenges include contaminated surface water from untreated domestic and industrial wastewater, and poor overall management of the available water resources.
Water resources management in El Salvador is characterized by difficulties in addressing severe water pollution throughout much of the country's surface waters due to untreated discharges of agricultural, domestic and industrial run off. The river that drains the capital city of San Salvador is considered to be polluted beyond the capability of most treatment procedures.
Water is relatively abundant in New Zealand due to the temperate climate and maritime weather patterns. In recent years, water pollution and draw-down of aquifers have become important environmental issues in New Zealand.
Grahamstown Dam is a major off-stream earthfill Embankment dam with a controlled labyrinth spillway and baffle chute that stores water from the Williams River. The dam is located north of Newcastle, New South Wales, Australia. The dam's main purpose is water supply; it provides about 40 per cent of the potable water for the Hunter Region; and is its largest drinking water supply dam.
