WSUD tree pit technical advise, City of Greater Bendigo and VicRoads
Recommendation to install 5mm mesh screen to minimise floating material entering the slotted distribution pipe of the infiltration trench. Sediment should settle in the pit below the inlet point.
VicRoads is undertaking an upgrade to a section of High St in Bendigo which required the removal of some mature trees. To give the replacement trees the maximum chance of success, City of Greater Bendigo (CoGB) advocated for the inclusion of WSUD principles in the VicRoads project. CoGB sought my advice on the merits of structural soil compared to structural cells and how best to introduce passive stormwater irrigation. I provided practical advice that will lead to a system that’s easy to maintain while maximising passive irrigation and tree health.
Passive irrigated replacement trees installed by VicRoads as part of the street widening project. Photo taken December 2018.
It appears the 5mm screen recommended for within the pit in front of the pipe entry has been utilised as a grated pit cover. As can be seen, this is filtering out larger organic matter which should be cleaned by the street weeper. However, there is the likely hood that, over time, the screen holes will block and therefore the water bypasses. Trapped material caught in the holes must be removed every year or two by removing the grate and jet washing the grates from behind and removing the material off-site.
WSUD tree pit technical advise, City of Greater Bendigo and VicRoads
