Following the recent Canterbury earthquakes the flood risk to large parts of Christchurch increased due to land damage, ground levels going down greater than 500mm in some places and lateral spread along the creeks draining large parts of the city.
The Dudley Creek catchment was particularly badly affected by the earthquakes and is an area that was already at a high risk of flooding prior to the earthquakes.
Three separate flood events in the autumn of 2014 led the Council to put in place a plan to fast track a land drainage scheme to return the Dudley Creek catchment to a pre-earthquake level of flood risk. Approximately 600 properties were at increased risk of flooding following the Canterbury earthquake sequence in this part of Christchurch alone.
The successful delivery of this $48M project relied upon a collaborative approach between Christchurch City Council, the Designer and the contractor as well as a high level of co-operation by the public and property owners who live alongside the creek.
Following the appointment of a Designer the first phase involved a high level of public consultation by Council to identify an option that not only met the criteria set to reduce flood risk but also had public ‘buy-in’ due to the impact that the works would have on their local environment.
The second phase was to appoint a Contractor under an Early Contractor Involvement Contract (ECI) to work alongside the Designer and Council to ensure delivery of a design that could be delivered to programme, within budget and meet the Council’s objectives of reducing the flood risk. Council have set an ambitious time frame of reducing the flood risk by the winter of 2017.