KEY POINTS:
A Coromandel waterway almost ruined from gold mining one century and farming the next has been restored to a fish-friendly natural stream in just 18 months.
Running through farmland and a new subdivision on the outskirts of Coromandel township, what was little more than a drain is now a clear running stream complete with "fish-ladder".
Howard Saunders, a landscaper with Natural Habitats, was put in charge of the Beach Rd stream restoration project, which was a resource consent requirement to allow residential development of the site.
Mr Saunders said conditions to protect waterways and wetlands were increasingly placed on subdivision consents as the issue of water quality gained national importance.
"Water is a diminishing resource we have to protect and enhance."
Mr Saunders created a fish-ladder using rocks to ensure there was no horizontal drop of more than 200mm, including by building little ramps, allowing fish like wild trout and native eels to migrate along the stream.
Locally sourced boulders were also used to create ponds and eddies and to provide a natural path so that during floods the fast flow would be interrupted to help protect the banks from being scoured out.
Mr Saunders said the waterway, once part of an old gold mining operation, had been further degraded by nitrification as a result of farming practices.
When he first inspected ponds along the stream they were opaque and bright orange but following the restoration work over a year ago, the water now ran clear.
The specially designed pools also allow sediment and silt to drop to the bottom instead of going out to sea.
"It is a good example of what can be achieved," Mr Saunders said.
The banks of the stream had been planted with a range of native flora like flax and long grasses which drooped over the waterway to create shade.
They kept the stream cool and comfortable for fish while also offering protection from preying birds.
Cabbage trees, kanuka and kahikatea have been planted alongside to eventually create an attractive forest of trees down one boundary.
"The finished result is both aesthetically pleasing and environmentally sound," Mr Saunders said.
Re-vegetation techniques were relatively new but if every farmer planted 10 trees each year, the difference would be substantial. "It took New Zealand just 20 years to destroy our natural forests and kauri and if we take this same attitude in re-vegetation, in 20 years we could be back to where we started."
