Worthing Borough Council commissioned the six-figure restoration of the lake after residents petitioned the council about its poor condition.
Contractors Five Rivers removed the equivalent of six Olympic-sized swimming pools of silt from the eight-acre lake, with a range of wildlife-friendly features installed.
Work includes a 105m-long boardwalk which will allow visitors to stroll along a reed-lined pathway to get closer to the wildlife.
The last few metres of the boardwalk are expected to be completed this weekend, with fences surrounding the lake while work bedded in to be removed in the coming days.
Councillor Edward Crouch, cabinet member for environment, said: “The transformation of Brooklands Lake has been astonishing – it’s been a really important piece of work that was highlighted and done in consultation with residents.
“As a result of the investment, the water quality is much better, the habitat has been improved and we are really making Brooklands fighting fit for the future.
“Now this is complete we appreciate that people now want us to push on with transforming the rest of the park. Rest assured we have been working hard behind the scenes on the masterplan and hope to be able to reveal our exciting plans in the next month or so.”
Work began on the revamp in October when Five Rivers began draining the lake. Teams then used excavators to move more than 15,000 cubic metres of silt at the bottom to create new margins and an extra island to provide a habitat for birds and other wildlife.
To avoid similar problems in future Five Rivers have narrowed the Teville stream in Valley Gardens to increase water flow which means future sediment is deposited in the wider area in front of the café.
This ‘sediment trap’, along with the ramped access point from Western Road, will allow easy access when material needs to be removed from the bottom of the lake in future years, the council said.
Ben Sharp, project manager for Five Rivers, said: “We’ve really enjoyed being able to work on restoring Brooklands lake.
“It’s been a great project, even though much of it has seen us wading through mud during an extremely cold and wet winter. A particular highlight was finding a snapping turtle in the mud.
“We’re literally just finishing the last few metres of the boardwalk now which means that this weekend we’ll be finished here and the council and residents will have the lake back.”