2. Mangatawa catchment consents for earthworks, storm water ...

• The spills into Papamoa urban area to not result in flood levels that exceed those implicit in the
District Plan in the context of minimum building platform levels.
Modelling has been undertaken to determine the current risk, and evaluate options to reduce that
risk. Recommended works include:
• Increasing the capacity of the Mangatawa Drain and to contain flood flows within the drain to a
higher level than currently occurs before spill;
• Improving the capacity of the Maranui swale to contain spills that do occur;
• Providing a flood overflow from the Maranui swale back to Mangatawa Drain at Mangatawa
Lane, associated with bank protection works along the lower Mangatawa Drain;
• Increasing the capacity of the current TCC stormwater treatment wetland to also treat the runoff
from the TEM and from proposed development of MPBI industrial zoned land south of the
railway.
The modelling confirms that appropriate outcomes can be achieved with the works proposed.
Beca // 17 March 2009 // Page 19
3932036 // NZ1-1604459-15 0.15 Rev A