Infrastructure Strategy 1.3 Ageing infrastructure 2. Options to respond to each of these identified The age profile of the stormwater pipes shows a relatively modest rate of replacement challenges, and implications of these options is required over the next 30 years. However, around 48 kilometres of predominantly concrete mains were laid in the 1960s and 70s and these will be reaching the end of 2.1 Increased stormwater volumes from subdivision their useful life just beyond the horizon of this strategy (around 2050/60). These development and climate change predictions are based mainly on the current knowledge of pipe condition and the Option Implications expected rate of deterioration. As discussed previously, anyactors influence the life expectancy of pipes. It will be important to gain more knowledge of the pipe condition Upsize infrastructure at the Benefits over the life of this strategy, so the projections can be refined and plans developed for developers’ cost to accept the replacement in a manageable renewals programme. A programme to CCTV survey maximum anticipated flows. Certainty of outcome. wastewater and stormwater pipes was instigated following the 2016 earthquake. The Follows the principle of ‘user pays’. survey has been targeted the pipes considered to be most affected (mainly earthenware and vitreous clay) in the areas where most damage is expected Costs (Blenheim) and the pipes that will have the most severe consequence of failure Disruption during the installation and escalating costs of (generally wastewater.) Some money has been budgeted for further assessment once development. the earthquake damage has been evaluated. Downstream consequences as the receiving waters reach capacity and also require infrastructure upgrades. Upsize infrastructure to Benefits accept maximum Certainty of outcome. anticipated flows and devise funding formula to Development costs are shared to assist with affordable spread costs. housing. Costs Disruption during the installation. Inequity as ratepayers fund private developments. Downstream consequences as the receiving waters reach capacity and also require infrastructure upgrades. PREFERRED OPTION Benefits Implement a combination of Total and peak discharge volumes are optimised. engineering interventions Minimises infrastructure upgrades and impacts on as part of an integrated downstream drainage. Stormwater Management Area Plan. Good coordination between urban stormwater and the receiving waters. Forms part of a coordinated river catchment strategy Costs Potentially requires set-aside land for stormwater 2018-2028 Long Term Plan Page 203