Application of an aerial catchment monitoring methodology to assist the development of drinking water safety plans

Risk-based management approaches for safeguarding the quality of public water supply, as strongly endorsed by the World Health Organisation and the Drinking Water Inspectorate, place greater emphasis on the importance of water companies knowing their catchments and their associated risks. Because of their often vast extent, and problems relating to access, it has always been a challenge for water companies to gather reliable data relating to catchment landuse and to monitor catchment activities. This paper presents a methodology that was used successfully within Cambridge Water to gain more knowledge about landuse within its catchments by chartering a helicopter and systematically photographing them. The method used is described, the results are shown and the strengths and the weaknesses of the approach are considered.