B-2 – Area 2 - Assessment of Environmental Effects 141 Discharge Receiving Environment Alternative Methods of Discharge adjacent waterbodies with limited adverse environmental effect due to the higher flows and mixing capacity of the waterbodies. Larger ponds would therefore provide limited additional environmental benefit. Discharge water to land within the Dry Detention Pond and to surface water via a spillway. Refer to Section 2 of this AEE. The Detention Pond is intended to manage runoff and discharges to the Mataura River for at least the pre-development flow rates for a two year and a 10 year storm event. The Dry Detention Pond is significantly oversized when compared to the 2% contributing catchment required by TR2009/02. Consequently, a high level of sediment retention efficiency is expected. Events greater than the capacity of the dry detention pond will discharge into the Mataura River via the emergency spillway when flows will be sufficiently elevated to provide effective dilution of contaminants. Given the oversizing of this pond, no further alternatives were considered. Discharge overburden onto land at the Willows Rock Stack. . Refer to Section 2 of this AEE. The storage of overburden needs to be discharged to these locations for operational reasons. Consideration was given to a range of different site designs, locations and methodologies for the storage of overburden as part of the optioneering and site selection process undertaken by WSP and EGL. These options are presented in the WSP (2022) and EGL (2002a) reports provided in Part H of these application documents. Discharge overburden onto land in stockpiles and earth bunds. Refer to Section 2 of this AEE. Discharge domestic sewage to land. Refer to Section 2 of this AEE. The discharge of treated domestic sewage to land is considered best practice and is culturally more acceptable that the equivalent discharge to water. The package treatment plant has been located remotely, away from the Mataura Stream and its tributaries.
RkJQdWJsaXNoZXIy MjE2NDg3