[[Image:noria.jpg|thumb|right|200px|Noria. Drawing: FAO]]
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An improvement to the simple rope and bucket is to fit numerous small buckets around the periphery of an endless belt to form a continuous bucket elevator. The original version of this, which is ancient in origin but still widely used, was known as a "Persian wheel"; the earliest forms consisted of earthenware pots roped in a chain which is hung over a drive wheel. The water powered "noria", a water wheel with pots, buckets or hollow bamboo containers set around its rim, is similar in principle except the containers are physically attached to the drive wheel circumference rather than to an endless belt suspended from it.
Depending on the assumption used for the power of the animals in the above examples, the implication is that the efficiency is in the order of 50% at medium lifts such as 6m and perhaps marginally better at higher lifts but worse at lower lifts.
===Suitable conditions===
The Persian wheel has been, and still is, widely used particularly in the north of the Indian sub-continent, while the noria was widely used in China, S.E. Asia and to some extent in the Middle East and being normally water powered. Both devices are tending to be replaced by more modern mechanical water lifting techniques as they are old-fashioned and low in output. It should be noted that the term "Persian wheel" is sometimes used to describe other types of animal powered rotary pumps.
The water-powered noria uses the same principle as the Persian wheel and therefore also needs to be of larger diameter than the pumping head, which either limits it to very low lift pumping or requires very large, cumbersome and expensive construction. Small, low-lift norias, used in Thailand and China, are very inexpensive while much larger norias are used in Vietnam and Syria. Some of the largest in Syria exceed 10m in diameter, but in relation to their size they tend to be unproductive compared with more modern pumping systems.
===Construction, operations and maintenance===
====Assembling a water wheel====
FOR A COMPLETE PHOTO SERIES, SHOWING THE ASSEMBLY OF THE WHEEL: [http://lurkertech.com/water/pump/morgan/tripod/ The story of a waterwheel.]
===Reference manuals, videos, and links===
* [http://lurkertech.com/water/pump/morgan/tripod/ The story of a waterwheel].
===Acknowledgements===
* [http://www.fao.org/docrep/010/ah810e/AH810E05.htm REVIEW OF PUMPS AND WATER LIFTING TECHNIQUES.] Natural Resources Management and Environment Department, Food and Agriculture Organization (FAO).
* [http://lurkertech.com/water/pump/morgan/tripod/ The story of a waterwheel.]
