Recent planning conferences, plus some of our previous posts, have highlighted the concerns that residents have with deep excavation for underground car parks and the irreversible problems that these constructions can cause. In a municipality that this prone to flooding, that has large areas of water table, and where basements are abutting neighbours’ fence lines, the prospect of real long term damage is high.
Council’s position has been: first grant a permit and then worry about such things as flooding, discharging polluted waters into the drainage system and lowering of the water table so that surrounding areas are susceptible to earth movement and instability. In contrast, the latest agenda items for Kingston contain a policy called “BASEMENTS AND DEEP BUILDING CONSTRUCTION POLICY”. If the policy is ratified, then Kingston will demand before any permit is granted the following:
Prior to application for a building permit, developers must conduct a site investigation to assess the local hydrology. The results of the site investigation must be presented to council in the form of a Groundwater Assessment Report Site limitations with respect to groundwater that have been identified in the initial design phase should be considered prior to the commencement of construction. Any excavation within 1.00 metre of the groundwater table will require a documented management plan to be submitted as part of or in conjunction with a Construction Management Plan. All necessary permits for the drainage of or de-watering of the site shall be in-place prior to construction commencing
Double depth excavations for two levels of basement car parking is now becoming more frequent in Glen Eira. Yet all council has done is include some ‘conditions’ in the planning permit about water discharge, etc. No real consideration has been given to what could happen to the groundwater levels; what could happen as a result of earth anchors; what could happen as a result of the cumulative impacts of such developments. Granting a permit and then trying to fix the problem is far too late as has been evidenced by several disasters in Carnegie.
If development is going to continue at the rate it is and with the proliferation of underground parking that reaches several levels, then greater surveillance, and far more restrictions on what can be done where is necessary. Sitting back and doing nothing is not the answer.
We have uploaded the entire Kingston officer’s report and the policy. Please refer to pages 210-235.