Waikowhai Stream
using ecostructure for infrastructure in a growing coastal town
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In the town of Raglan, locals rediscover the name of a stream labeled as a drain. Their interest alerts both the regional council to native fish in waterway and the local council to a new appreciation of waterway as a wildlife corridor. Plans to pipe stream are halted.
one view of stream: roll mouse over image to view namesake

from summary document

The Waikowhai Stream today is an important structure of the local ecology (known in landscape ecology as an ecostructure).

For many years, as the town of Raglan has developed, it has also been used as an important part of engineering in the human environment (in landscape ecology, this engineering is called infrastructure).

Currently, its potential as a wildlife corridor as well as a stormwater drain is both in jeopardy: neither works very well. There is growing determination by local landowners to revitalize the relationships with local and regional councils with the goal of restoring the stream’s capacity for both roles.

Today, in the twenty-first century, there is a good understanding of the importance of ecostructure and the often-negative impacts of many infrastructure designs. There is also a renewed appreciation of the capacity that the ecostructure has to handle these impacts and even thrive.

The key to this success is to enhance what a waterway will naturally do. Until recently, many engineering solutions forced the waterway into new functions with concrete, pipes, gates and ditches – impermeable surfaces, sometimes even enclosed, of straight lines and steep walls.

These are now recognized to force flooding, increase sedimentation and hurry pollutants into the sea. Blockages create mosquito filled swamps and marshes out of once firm floodplain areas. Flooding becomes more common and there is less capacity for receiving these waters, settling sediments and dealing with contaminants.

The alternative is to identify the natural features of a waterway, reinforce the physical structure and incorporate plants and wildlife as well. Altogether, the different components achieve a final result often much greater than any individual part. Key features are the flow of the stream, its meanders, the banks of the stream, its vegetation and the presence and absence of aquatic life and wildlife.

roll mouse over image above for a view of stream

35% of all landowners contributed to
1) two meetings (Sept- Nov 2002) (25 people)
2) mail drop survey (8 returned)
3) a group walkabout of entire waterway
(Nov) (12 people)
4) plus several dozen phone calls

Waikato District Council commissions a survey of all streams in township. The Waikowhai is formally identified as having high natural & amenity value.