Plans to improve Arundel Lido and bring a public gym to the town will be considered by South Downs National Park Authority.
Approval has been recommended to the planning committee, which is meeting at the South Downs Centre Hall, Midhurst, on Thursday morning.
In his report, Tim Slaney, director of planning, said a site management plan should be approved before any building work began, including ensuring noise was monitored. An acoustic report was also advised.
The plan, called Project LEAP, includes a new two-storey building with gym, multi-function hall, reception area, heated changing rooms and indoor café.
The lido, in Queen Street, Arundel, has two open-air swimming pools and large grounds, making it a popular place to visit in the summer.
Mr Slaney said in his report: “It is recognised as an asset of community value in the Arundel Neighbourhood Plan 2014, which also contains a site specific policy that supports its development for additional community and recreational facilities.
“The building would be built on the footprint of some of the existing buildings at the site entrance, including on the footprint of the existing changing facilities.”
He pointed out the lido was on a sensitive and unique site, a gateway location to the town, but said the design would conserve existing views of Arundel Castle.
Mr Slaney said: “The proposals would create a greater level of activity on site throughout the year in comparison to its current more seasonal use.
“Concerns have been raised about noise and disturbance. Environmental Health have not objected, subject to conditions.
“It has been concluded that this issue is largely addressed through the design and siting of the building and the recommended conditions.”
The lido is well-established, dating back to the 1960s, but it has had a mixed history, including its closure in 1999.
David Wood, chairman of Arundel and Downland Community Leisure Trust, said the charity was formed after a campaign to re-open the pool and it now runs the lido on a long lease from Arun District Council.
The trust also operates the car park, which provides funding to keep the lido running.
Mr Wood said the trust’s consultation in 2015 had confirmed local demand for the facilities.
Generous grants from the district council and Coast to Capital Growth Fund enabled the trust to carry out the work needed to prepare the planning application, costing around £130,000.
Architect Adam Richards was appointed inMarch last year and his designs were accepted in September.
Mr Wood said the design had been firmly supported by the trustees of Arundel Castle, as well as the Duke and Duchess of Norfolk.