Comment by RodgerTheGreat

if you insist on verbose names, they're always an option in K:

    west_scan           : |\   A
    east_scan           : ||\| A
    water_level         : west_scan & east_scan
    height_water_column : water_level - A
    max_height          : |/ height_water_column
    total_water         : +/ height_water_column