Current translation for Blackham
  black derived from blaec  – black or black land
  ham derived from hamm  – Denotes a piece of land surrounded with paling, wicker-work, etc., and so defended against water, which would otherwise wash it away, so a valley settlement or settlement with a jetty.
“Black or black land denotes a piece of land surrounded with paling, wicker”
Place name translation provided by saxonhistory.co.uk