‘Many hands make light-ish work’, so we are very thankful, and very impressed, by everyone who lent a helpful hand (or two) sandbagging the new regulator at Walker Swamp. The filling and placement of 2500 sand bags may have set a new NGT record! But we did a lot of homework first.
A very thorough hydrological study informed the decision to raise the sill level of the swamp another 50 cm above the temporary regulator height (put in place three years ago). Some nifty 2D hydrological modelling by Lachie showed the new water level would fill an extensive region of the Walker Swamp floodplain.
We also had two highly qualified volunteers (Brenton Puddy and Michael Talanskas) help survey the drain profile for the new regulator and its spill height, and most importantly checked these heights against existing levee heights, verifying the accuracy of the terrain and 2D modelling.
That brought us to the next ingredient – a mere 90 cubic metres of sand to form the regulator. Easy! All we had to do was fill over 2500 geofabric bags with 64 tonne of sand, and then use the bags to build the regulator – all before the season broke and the wet-cycle resumed.
More willing and able volunteers to the rescue!
NGT stalwarts Lachie, Mark and Greg, ably assisted by Mark’s son Dale, spent a day setting the foundations in place in preparation for the big team of workers.
A team of 12 volunteers (Lisa McIntyre, Rosemary Wray, Sarah Patterson, Tom Ferguson, Doug Craig, Jo (Dixie) King, Rod Bird, Trevor Flynn, Peter Hocking, Paul Yule and Pauline Yule) assisted by a crew of eight from the Landmate group, and eight NGT staff, filled and placed the bags in a day and a half – what an effort!
With heavy rains over the last week, we look forward to tracking the effect of the regulator on future water levels as our incredible crew’s efforts are put to the test. Check out the time lapse photography: