[[Image:floating {{Language-box|english_link= Water Portal / Rainwater Harvesting / Surface water / Floating intake icon.png|right]]french_link= Prise d'eau flottante| spanish_link= Toma flotante | hindi_link= वाटर पोर्टल / वर्षाजल संचयन / सतही जल / तैरता जल-संग्रहण | malayalam_link= Coming soon | tamil_link= Coming soon | korean_link= Coming soon | chinese_link=漂浮引水口 | indonesian_link= Asupan menambang | japanese_link= 浮遊取水口}}
[[Image:intake icon.png|right|80px]][[Image:FloatingIntakePond.jpg|thumb|right|300px200px|When choosing a river intake location, select one with few rocks and boulders, so that the intake system does not get damaged. These types of locations are further downstream, as opposed to higher elevations.]]Floating intakes for drinking-water systems allow water to be abstracted from near the surface of a river or lake, thus avoiding the heavier silt loads that are transported closer to the bottom during floods. The inlet pipe of a suction pump is connected just under the water level to a floating pontoon that is moored to the bank or bottom of the lake or river. The pump itself can be located either on the bank or on the pontoon. The advantages of placing the pump on the pontoon are that the suction pipe can be quite short and the suction head will be constant (less risk of cavitation). If the river currents frequently carry logs or large debris, a floating inlet needs extra protection or it will be damaged. To construct the pontoon, a steel or wooden frame can be attached to floats made from empty oil drums, plastic containers, or sealed steel tubes at least 30 cm in diameter.
'''Floating intakes''' for drinking-water systems allow water to be abstracted from near the surface of a river or lake, thus avoiding the heavier silt loads that are transported closer to the bottom during floods. The inlet pipe of a suction pump is connected just under the water level to a floating pontoon that is moored to the bank or bottom of the lake or river. The pump itself can be located either on the bank or on the pontoon. The advantages of placing the pump on the pontoon are that the suction pipe can be quite short and the suction head will be constant (less risk of cavitation). If the river currents frequently carry logs or large debris, a floating inlet needs extra protection or it will be damaged. To construct the pontoon, a steel or wooden frame can be attached to floats made from empty oil drums, plastic containers, or sealed steel tubes at least 30 cm in diameter. ===Suitable conditions===[[Image:FloatingIntakeLocation.jpg|thumb|right|300px200px|Location of a pond intake, near village. Click to zoom. <br> Drawing: [http://www.lifewater.org/resources/rws1/rws1c2.pdf Water for the World.]]]
Rivers or lakes.
Intake designs aim to avoid clogging and scouring and to ensure the stability of the structure even under flood conditions. Where the river transports no boulders or rolling stones, an unprotected intake may be adequate.
===Resilience to changes in the environment===
====Drought effects on cement====
More information on managing drought: [[Resilient WASH systems in drought-prone areas]].
===Construction, operations and maintenance===[[Image:Floating Intake Diagram.jpg|thumb|right|300px200px|A floating intake diagram. Click image to zoom. <br> Drawing: WHO.]][[Image:Floating Intake Big Diagram.jpg|thumb|right|300px200px|Floating intake cross section view of pond or lake. Click image to zoom. Drawing: [http://www.lifewater.org/resources/rws1/rws1p4.pdf Lifewater.org.]]]
A floating-intake system is usually operated by a caretaker. The pump and inlet pipe must be checked before and during pump operation, and any obstructing debris removed and damage repaired. This is particularly important during the rainy season. Every day, the mooring cables should be checked and adjusted if necessary, and the flexible pipe connections checked for leaks. Any damage to the mooring or the pontoon structure must be repaired immediately, which may require the assistance of several people. Depending on the materials used, the pontoon should be painted regularly, at least once a year for steel parts.
— the lake or river water may be of poor quality.
[[File:floatingIntakeOM.jpg|thumb|centernone|600px500px|Operations and maintenance roles. Click chart to zoom in. Chart: WHO.]]
====Screens====
The water should flow towards the bar screen at a quite low velocity, 0.1-0.2 m/s. Once the water has passed the screen, the flow velocity should be at least 0.3-0.5 m/s in order to prevent the settling out of suspended matter. In the openings between the bars the velocity of flow should be limited to a maximum of 0.7 m/s; otherwise soft, deformable matter will be forced through the screen openings. A clean screen will allow the water to pass with a head loss of only a few centimetres. However, the head loss rises sharply when the clogging of the screen builds up. Regular cleaning should keep the head loss limited to 0.1-0.2 m head of water. Allowing for delayed cleaning and mechanical failures, it is good practice to design a bar screen for a head loss of 0.5-1.0 m.
==Costs== ==Reference manualsManuals, videos, and links===
* [http://www.lifewater.org/resources/rws1/rws1p4.pdf Choosing where to place intakes.] Water for the World.
* [http://www.lifewater.org/resources/rws1/rws1c2.pdf Constructing Intakes for Ponds, Lakes and Reservoirs.] Water for the World.
* [http://www.watersanitationhygiene.org/References/EH_KEY_REFERENCES/WATER/Surface%20Water/Maintaining%20Intakes%20%28USAID%29.pdf Maintaining intakes.] US AID.
* [http://www.samsamwater.com/library/TP40_11_Surface_water.pdf Surface water intake and small dams.] Nhamo Masanganise.
* [http://docs.watsan.net/Downloaded_Files/PDF/Lauterjung-1989-Planning.pdf Planning of Water intake structures for irrigation or hydropower]. Helmut Lauterjung / Gangolf Schmidt. A Publication of GTZ-Postharvest Project, 1989.
===Acknowledgements===* Brikke, François, and Bredero, Maarten. ''[http://www.googlewashdoc.cominfo/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0CC0QFjAB&url=http%3A%2F%2Fwww.who.int%2Fwater_sanitation_health%2Fhygiene%2Fom%2Flinkingintro.pdf&ei=cwJpT-zaO-OiiQKCst2rBw&usg=AFQjCNEWOQhTgF3a7lzhuw5OA2KmbVGxcA&sig2=Rt2EURUyGVqDcwFg6p0xAw docsearch/title/117705 Linking technology choice with operation and maintenance in the context of community water supply and sanitation: A reference document for planners and project staff]''. World Health Organization and IRC Water and Sanitation Centre. Geneva, Switzerland 2003.* [http://www.lifewater.org/resources/rws1/rws1p4.pdf Choosing where to place intakes.] Water for the World.
* [http://www.samsamwater.com/library/TP40_11_Surface_water.pdf Surface water intake and small dams.] Nhamo Masanganise.