The existing wave wall will be strengthened with concrete reinforcements in a project which is expected to last about eight weeks.
While the work is carried out a short stretch of the footpath along the embankment will be closed, with a signposted diversion route in place.
The reservoir water level has been lowered in advance of the work to make it easier for the engineers to carry out their work and to ensure their safety.
John Bond of Yorkshire Water's community engagement team, said last night: "Whilst this is one of our quieter reservoirs in terms of visitor numbers, we recognise that any work is disruptive to those who do use the site and we want to reassure them that we'll be working as hard as possible to get the necessary improvements completed as quickly as possible.
"The work we are doing on the Victorian dams and reservoirs across Yorkshire will enable us to continue to safeguard the high quality water supply to the region for many years to come."
Yorkshire Water or its contract partners will not need access to any properties during the work and is advising local residents to be vigilant about bogus callers, reminding them to ask to see identification if they are in any doubt. Genuine employees of both companies carry identity cards which can be checked by telephoning 0800 1 38 78 78 and they will not mind waiting while their details are verified.
Anyone wanting to find out more about the reservoir improvements scheme in Yorkshire should visit www.yorkshirewater.com/reservoirs