Ka cika wannan jumla: A matsayin Injiniyan Jihar California, Hall ya yi aiki a kan cikakken tsarin samar da ruwa da kuma sarrafa ambaliyar ruwa ga kwarin Sacramento. Nazarin Hall na ilimin hydrology na California ya kasance daga 1878 zuwa 1883. A wannan lokacin, ma'aikatansa sun girka babban tsarin auna kwararar ruwa tare da wasu kogunan California. Ya kuma taimaka wajen tsara ayyukan don taimakawa San Francisco samun wadataccen ruwa daga yankin yammacin kogin Tuolumne. Bayan da
Girgizar kasa ta 1906, San Francisco ta sami damar tabbatar da haƙƙin ruwa, kuma ta ambaliya Hetch Hetchy Valley.