Riparian planting, storm water mitigation, slope stabilisation.
The January 27th Auckland flood has me thinking about flood mitigation because storm water run-off has caused a bank to slip into a stream on our Auckland property, but also the culvert running onto our Rakino property has barely stopped running this year, and has consequently dug itself a stream channel which was once ephemeral, but now seems a permanent fixture.
We want to slow the water flow down so as to avoid scouring and flushing out of sediment, and we want to ensure the water is cleaned of any contaminants before it eventually ends up in the Hauraki Gulf. It’s always been the way to pass run off and storm water to the properties downhill, but I think we need to increasingly look at mitigating at the source, water collection, riparian planting, and establishing ‘cleaning’ plants like carex in wetland areas.
Here are a couple of interesting studies from Landcare Research for perusal..
https://icm.landcareresearch.co.nz/research/research.asp?theme_id=1&research_id=13
https://icm.landcareresearch.co.nz/knowledgebase/publications/public/Roots_October08.pdf