What will the dams look like?

    Unlike what most people consider a dam to be, the proposed Morey Street dams will be built to control water flow rather than store it for future use. They will look like large grass embankments with a concrete lined chute to one side, and a small rock lined basin at the base where a pipe carries water into the stormwater network. 

    The dams will be constructed from soil and gravel mainly sourced from the adjacent Wharenui Rise development. Following construction, the dam faces will be hydro-seeded so ultimately they will look like gently sloping grass mounds. The Morey Street West dam embankment will be approximately 10m above existing ground level at its highest point and the Morey St East dam embankment will be approximately 16m above ground level at its highest point. 

    How do the dams work?

    During rain events, stormwater will flow through a pipe at the base of the embankment and into the stormwater network. During more significant rain events (storms, cyclones etc) stormwater will build up behind the embankment (like a pond) and once the rain event passes, the stormwater will continue to flow through the pipe until the dam empties. By holding this water back, (attenuating the flows) any flood levels downstream are reduced.

    The dams are designed in such a way that they are able to detain stormwater from very large flood events. It is important to note that the water will only pond behind the dam in significant rain events. At all other times it will be an empty grass valley.  

    I live below Morey Street – does this mean that the risk of flooding will be reduced on my property?

    The dams will reduce flooding effects on downstream properties during storm events when compared to if the dams were not constructed.  Flood modelling has been undertaken to show how flooding effects will be reduced for a range of different scenarios.  You can check out the website www.rotorualakescouncil.nz/moreystreetdams to see the changes to flooding risk on your property.

    Are the dams safe?

    The dams will be designed and constructed to the highest standards in accordance with the New Zealand Dam Safety Guidelines and we will implement an on-going dam safety management system for the life of the dam that will include monthly inspections.

    What are the effects of the dams on the downstream catchment?

    The dams are designed to reduce flooding effects on the downstream catchments. This is because, during rain events, the dams will help to control the flow of water down the catchment to the lake. This will reduce the potential for flooding that occurs when large amounts of water flow through the stormwater network uncontrolled.

    Who has helped Council develop the designs for the dams?

    Council has worked with environmental and engineering consultants Tonkin & Taylor to develop the designs for the dams. Council is also engaging with Eastside partners Tatau Pounamu and Eastside hapū, landowners Ngāti Whakaue Tribal Lands and Te Arawa Lakes Trust.

    What considerations has Council given to stormwater quality?

    Council is in the co-design process with Eastside hapū and landowners Ngāti Whakaue Tribal Lands to develop a wetland that will help to improve water quality of the stormwater runoff from the proposed upstream subdivision before it enters the downstream channel and Lake Rotorua.

    When will the work start and how long will it take?

    Council must first gain Resource Consent to proceed with the construction. It is expected that process will be complete by mid-2022. Following that process, the proposed works will take approximately 6-8 months to complete.  

    How will the construction of the dam affect me?

    Neighbouring residents (McKenzie Road and Hayward Rise) may experience noise and vibrations from time to time, depending on where work is taking place. If you live nearby, or use Morey Street regularly, you may be impacted by vehicle movements and traffic management. Please note that where possible, contractors will keep all impacts to a minimum.

    How does the resource consenting process work?

    The resource consent application will be lodged with Bay of Plenty Regional Council and Rotorua Lakes Council who will process the applications. Certain people may receive further notice of the application once lodged in relation to the effects of the activity.