Nutse tafkin

Ruwan tafki (ko kwandon ruwa ko tafkin ruwa) babban bakin ciki ne a cikin gadon rafi a gindin magudanar ruwa ko rufewa. An halicce shi ne ta hanyar ruɗaɗɗen ruwa na zubar da ruwa a kan duwatsu a tushen kafa inda ruwa ya yi tasiri.Marshak, Stephen, 2009, Essentials of Geology, W. W. Norton & Company, 3rd ed. ISBN 978-0393196566Kalmar na iya nufin ruwan da ke shagaltar da baƙin ciki, ko kuma baƙin ciki da kansa.Robert L Bates, Julia A Jackson, ed. Dictionary of Geological Terms: Third Edition, p. 391, American Geological Institute (1984)

 Samuwar 
An kafa wuraren tafkunan tafkunan ta hanyar ƙarfin faɗuwar ruwa, kamar a magudanar ruwa ko tudu; suna kuma haifar da tsarin da mutum ya yi kamar wasu zane-zane na zubewa.The Management of the Zambezi River Basin and Kariba Dam, p. 105 (2010) Ruwan tafki sau da yawa suna da zurfi sosai, gabaɗaya suna da alaƙa da tsayin faɗuwar, yawan ruwa, juriyar dutsen da ke ƙasa da tafkin da sauran abubuwa.Vincent J. Zipparro, Hans Hasen, Davis' Handbook of Applied Hydraulics, p. 16.46 (1993) Ruwan da ke da tasiri da jujjuyawa, wani lokaci yana ɗauke da duwatsu a cikinsa, yana karkatar da gaɓar kogin zuwa cikin kwano, wanda galibi yana nuna ɓangarorin da ba su dace ba. Tafkunan ruwa na iya zama dadewa bayan ruwan ruwan ya daina gudu ko kuma aka karkatar da rafin. Misalai da yawa na tsoffin wuraren tafki suna wanzu a Dry Falls a cikin Channeled Scablands na gabashin Washington.The Channeled Scablands of Eastern Washington: the geologic story of the Spokane flood , p.18-19 United States Geological Survey (1973) Ana kuma iya samun su a karkashin ruwa a wuraren da a da suke sama da matakin teku, misali, Perth Canyon da ke gabar tekun yammacin Ostiraliya.

Plunge wuraren tafkuna siffofi ne na zazzagewa waɗanda ke faruwa a lokacin ƙuruciyar haɓakar

kogin, wanda ke da madaidaicin gradients da saurin ruwa. Inda dutsen da ya fi laushi ko ya karye ya koma wani wuri, ruwa yana ci gaba da jefa bam a gindinsa. Saboda wannan dutsen sau da yawa ba shi da juriya fiye da kifaye, ruwan da ke sama yana ci gaba da zubewa ƙasa har sai an sami daidaito.

Wani siffa mai kama da kwano da ke gudana ta hanyar ruwa mai gudana, sabanin faɗuwar ruwa, an san shi da rami mai zubewa. Wadannan suna faruwa duka ta halitta da kuma sakamakon ginin gada.

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