Amanzi angaba khona ngendlela ezintathu – abelirhwaba, amamanzi, nanyana irhasi. Ukurhwamuka yikambiso lapha amanzi atjhuguluka abasitimu. Ekambisweni le, amanzi asuka elwandle, emadamini, emilanjeni kanye nentjalweni ezimanzi.
Ukurhwamuka okusuka elwandle nanyana emadamini kurholela ekutheni kune izulu, kodwana umrhwamuko osuka emadamini abeke amanzi wokuthelelela amraro. Amadamu amakhulu angatjhingeliko, eendaweni ezitjhisako, ayatlhayela.
Yini Ebanga Umrhwamuko?
Amandla atlhogeka ekutjhugululeni ama-molecules wamanzi ekubeni stimu. Imisebe yelanga isipha amandla, kodwana kunezinto ezimbalwa ezenza kobana kube nestimu.
Amazinga womtjhiso
Amazinga womtjhiso aphezulu angezelela istimu.
Ubuswe
Umoya owomileko ungezelela umrhwamuko.
Umoya
Umoya owomileko otjhisako ujamiselela umoya onobuswe begodu kurholela ekutheni kube norhwamuko msinya. Lokhu kumthelela oqakathekile emlanjeni we-Orange River ophasi, Vaalharts, Riet River kanye neskimu okuthelelela e-Sandvet nendaweni zokulima ezithola imimoya evela e-berg.
Imimoya, enobuswe epholileko ebuya elwandle ingezelela ubuswe begodu iphungula izinga lomrhwamuko.
Umrhwamuko Kanye Netlayimedi YeSewula Africa
Esewula Africa ilele emideni ephakathi. Amazinga womtjhiso wayo alele hlangana kwe-30 ukuya ku-60 yama-degree epumalanga kanye netjingalanga. Ukungezelela, iSewula Africa inamazinga aphezulu womtjhiso kanye nobuswe obuphasi koke okurholelwa zizinto eziletha umrhwamuko phezulu.
Umrhwamuko endaweni ekulinywa kiyo ethola izulu eliyi-500 mm ngonyaka lihlangana kwe-2 000 kanye ne-2 600 mm ngonyaka. Madaniswa lokhu nendawo ese-Europe ephakathi, ethola izulu elifana nalelo ngonyaka.Indawo le inerhonakalo lokuba nomrhwamuko wezingeli oyi-300 mm kwaphela ngonyaka ekulizinga eliphezulu kunelezulu.
Esewula-Africa umrhwamuko ungaphasi kwe-1 400 mm qobe nyaka entabeni zeMaluti nanyana ze-Drankensberg zidlule ku-2 800 mm ngonyaka eencenyeni zeKalahari. Kunobuhlobo hlangana kwezulu elijwayelekileko kanye nomrhwamuko ojwayelekileko, lokha izulu lina khulu, umrhwamuko uyancipha.
Kuqakathekile ukutjheja bona irhonakalo yomrhwamuko ophezulu eendaweni ezithelelelwa khulu zeSewula Africa, ezifana nemlanjeni we-Orange River ophasi, Douglas, Rama kanye nendaweni ze-Barkley West.
Umrhwamuko Kanye Nehlabathi
Okumumethwe mamanzi ehlabathini kudlala indima eqakathekileko ekulobeni komrhwamuko. Urhwamuko ubuya ehlabathini engaphezulu eku-15 ukuya ku-20 cm. Umrhwamuko uba khona msinya phezulu ehlabathini enamanzi eseduze kwemasimini. Ubukhulu besimu mamanzi asele ehlabathini ngemva kokobana amanzi amanengi sele adreyinekile.
Imigodi emikhulu esehlabathini ezele umoya kanye amanzi lokha imigodi emincani isazele amanzi.
Lokha nawuthelelelako, linga ukuphungula umrhwamuko. Ungenza lokhu ngokungezelela ubukhulu bamasimu. Faka amanzi amanengi lokha nawuthelelelako ulinde iskhathi eside ngendlela ongarhona ngayo ngaphambi kokobana uthelele godu. Lokhu kungezelela iskhathi sokobana ihlabathi iphungule umrhwamuko.
Nanyana kunjalo, ukobana ihlabathi ihlale yomile ngokobana uyithelelele kancani ngaso soke iskhathi kurholela ekutheni kube nomrhwamuko osezingeni eliphezulu.
Iintjalo ezivala ihlabathi zingasetjenziselwa ukuphungula umrhwamuko ehlabathini.
I-Evapotranspiration
Umrhwamuko kuphuma kwamanzi ehlabathini lokha i-transpiration kukuphela kwamanzi emakarini eentjalweni aphela ngestimu Lokha nakutjalwako, pheze yoke i-evapotranspiration ikumurhwamuko ehlabathini, kodwana lokha iintjalo nazikhula ehlabathini zivalwe makari wentjalo. Emakarini avaleke kuhle i-90% of evapotranspiration ibuya ku-transpiration.
I-Evapotranspiration silinganiso se-evapotranspiration etjanini ngokuqala imirhwa. Ethize begodu engatlhayeli amanzi. Lokhu kusetjenziswa njengesimedo setlhogakalo yamanzi eentjalweni zoke.
Translated by Busisiwe Skhosana