Rashin ƙarfi na ruwa

Hydraulic roughness shine ma'auni na adadin juriya na ruwa yayin wucewa a kan ƙasa da siffofin tashar. Yana ƙididdige tasirin rashin daidaito na ƙasa da cikas akan kwararar ruwa. Ɗaya daga cikin ƙididdigar  shine Manning's n-value. Ana amfani da n na Manning sosai a duniya don yin hasashen matakin tsananin a cikin tashoshi. Coefficient yana da mahimmanci a cikin injiniyan ruwa, kula da ambaliyar ruwa, da nazarin jigilar turɓaya. Saurin gudu ya dogara sosai da juriya ga gudana. Karin wannan darajar n zai haifar da raguwa a cikin saurin ruwa da ke gudana a fadin farfajiya.

 Manning ta n 
Darajar n na Manning tana shafar masu canji da yawa. Abubuwa kamar ɗora nauyin da aka dakatar, Girman hatsi, kasancewar dutse ko duwatsu a cikin tashar rafi, bambance-bambance a cikin faɗin tashar da zurfin, da kuma yawan hanyoyin tashar rafin na iya shafar darajar Manning. Misali, wani kunkuntar tashar dutse tare da cikas mara kyau kamar manyan duwatsu za su sami darajar n mafi girma fiye da mai santsi, madaidaiciya tashar tare da zurfin iri ɗaya.

Abubuwan halittu suna da babban tasiri a kan Manning's n; mahimman tasirin sun haɗa da daidaitawar banki ta hanyar ciyayi, tsawo na ciyawa da burbushin a fadin ambaliyar ruwa, da kuma kututture da katako da ke haifar da madatsar ruwa sune manyan tasirin da ake gani.

Bugu da ƙari, canje-canje na yanayi a cikin yawan ciyayi da girma na iya haifar da canji a cikin dabi'un Manning n.

 Muhimmancin Halitta 
Bincike na baya-bayan nan sun sami alaƙa tsakanin tsananin ruwa da mazaunin salmon spawning; "girman hatsi na gado yana amsawa ga tsananin hydraulic wanda ya haifar da rashin daidaito na banki, sanduna, da tarkace na itace... Mun ga cewa tarkacewar itace yana taka muhimmiyar rawa a wuraren bincikenmu, ba kawai samar da tsananin ruwan ruwa ba har ma yana tasiri ga sararin tafkin, mitar rubutu, da tsananun ruwa na tashar da ke haifar da tsananar ruwa mai tsananin tsananin tashar ruwa mai tasowa da tsanani da tsananirrai. Yanayin rubutu na gadajen rafi na iya shafar fiye da kawai wuraren zama na salmon, "bar da itace suna haifar da nau'ikan nau'ikan rubutu, suna ba da kewayon wuraren zama na ruwa waɗanda zasu iya inganta bambancin halittu ko amfani ga takamaiman dabbobi a matakai daban-daban na rayuwa.

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