Hydrographic surveys are carried out on dams or rivers where the profile of the dam or river bed is modelled for volume and design purposes. The surveys are carried out using a boat or kayak fitted with depth sounding equipment linked to a GPS receiver. NPM completed the survey of 18 dams within a 6 week period during 2011. In 2012, NPM was involved in the survey of the river bed profile of the Fish River near Port Alfred. This survey was particularly challenging in terms of access, wildlife (hippo) and heavy rainfall during the survey campaign. River profiles have also been surveyed in Fort Beaufort and Cala.