"THERE are creeks like this all over Sydney," says Sarah Renwick, the horticulturalist who has supervised the unlocking of the ancient water courses that greeted Major Weston, the colonial founder of the Horsley estate.

"We just haven't seen the creeks as assets. Rather, we've seen them as 'we can't build there because it is wet'.

"For many years we have called these areas bogs and swamps. We need to change that language. They are not 'drainage lines'. They are creeks, water courses and wetlands which have their own asset value. No one wants a bog in their backyard. But if you have got a creek where your kids can play - fantastic."

To Renwick, what has been achieved at the former rubbish dump is a lesson for many of us.

Material Landscape Architecture, the Surry Hills company she works for, was appointed by Tisdale in March to remediate the property. She was struck by how "boring and artificial" it was: "We needed to reinstate the natural geography, work out where the natural hydrology was going to lead us, then work with it rather than against it."

Early on, a decision was made to divide the site into three. The newly created lake takes up one-third, the houses another, with the final area devoted to regeneration of the natural vegetation.

But the water which runs into the lake is no longer in the pristine condition it was in Weston's day. Pollution higher up the water table has taken its toll. With landscaping and planting, the site is intended to be self-cleansing. The combination of plants in the lake itself and on the banks will gradually purify the water, Renwick says.

Despite the $200,000 cost of the landscaping, Renwick insists there is an economic benefit to restoring the natural water course. "It's not just about making the land healthy and beautiful. It makes it more valuable and gives the owner better use of his land."

Steve Meacham