Lunjani udaka olusebenzayo luphume enqwabeni enesithukuthezi? Le yinkinga enzima yokumba ukwakhiwa kwezinqwaba. Uhlelo lwendabuko lokubhola nokugungqa inqwaba yensimbi yile: ngenqubo yokumba ukusetshenziswa kwe-sieve, udaka ku-gravel omncane, isihlabathi nezinye izinhlayiya eziqinile zokwehlukanisa, ukunqwabelanisa udaka olukhishelwe kusinki, amasinki amabili echibini lamanzi amathathu, kugcwele imvula. Ngesikhathi kwenziwa inqubo yokwakha, kusetshenziswa abembi ngesikhathi esifanele ukuhlanza usinki, isiziba sokucwila ezimbili, ichibi ezintathu le-sink, ukuhlanza ukucwila ethangini elihwamukayo, kuze kuphulukiswe ukonakala kwemvelo, kuthunyelwe egcekeni lokugcina noma emathangeni. Lolu hlobo lokuphathwa ngodaka, ngenqwaba encane engenakwenzeka. Uma inani lezinqwaba zenani elikhulu lodaka olukhulu, le mpatho yodaka ayisebenzi.