The PlansThames Water want to strip out all the vegetation (including felling an avenue of mature trees) and bore a vertical shaft 100 feet wide and 250 feet deep (potentially bringing a risk of subsidence), as part of the proposals to construct a 30 mile 'super Sewer'.
The rest of the park would then be used for the storage and processing of enormous volumes of waste - dry-spoil that would be piled up pending removal, and foul-smelling slurry, which would be pumped into settlement tanks. There would also need to be an industrial jetty with a conveyor system to move processed waste from the site.
This work would continue for 7 years with a 45 foot high sewer ventilation shaft bringing a risk of horrible smells in the local area, as well as a 30 foot high 20-metre x 10-metre sewer building dominating what's left of the riverside park on completion, essentially converting this park to industrial use.
Thames Water's Plans
Thames Water's real plans
Slide show of King's Stairs Gardens
King's Stairs Gardens Site Selection Document
KSG Site Suitability Report
In their own words
Google map of King's Stairs Gardens