Immediately following Cyclone Gabrielle, the AgFirst Tile Drains project team carried out a risk assessment across all our tile drains monitoring sites to determine any site-specific impacts to our equipment and sampling ability, as well as the new Health and Safety risks.
We have experienced a range of different cyclone impacts across all our monitoring locations. We took no samples during the month of February due to site accessibility and various Health and Safety risks (silt, flood water, bank erosion, collapsed canopies etc). However, after working with site participants and managing these risks, from the 8th March our fortnightly grab sampling schedule continued across all but one site.
With Massey University’s help, we have been carrying out repairs and maintenance on all our proportional sampling and flow metering equipment. This has included flushing them all of silt, realigning them in the drains and some rewiring of flow meter controllers where they were inundated with floodwater. Most of our equipment is now back up and running with proportional samples now being taken, but there are still further repairs required at the sites in Pakowhai and Fernhill where the impacts were greater.
While servicing our equipment, we also downloaded the stored data from our flow meters. We were able to capture some tile drain flow data from the cyclone event across 6 of our 8 flow metered sites, and this is currently being analysed.
The team has undergone a lot of “passive project extension” with many discussions around the importance of drainage, and the impacts of high intensity, high flow events.
If you have any specific questions or analysis angles which you think may be worthwhile to look into and include in our project evaluation following Cyclone Gabrielle, please let us know.