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

More documents

Recommendations

Info

NZ Transport Agency and Tauranga City Council Mangatawa Drain Flood Bypass and TEM Stormwater AEE The water levels, peak flow rates and velocity for the preferred option for the 100 year flood are given in the table below. These have been determined with a hydraulic model of the drainage system. The following table summarises the 1% AEP results along the Maranui floodway at the stormwater treatment wetland and lower Mangatawa drain. The current day to day flows along the Mangatawa Drain will remain the same. The peak rate however can be higher than the present due to the drain capacity improvements. Table 10: Hydraulic Results 1% AEP Mangatawa Drain Maranui floodway Corridor Peak flow Peak Water Peak Corridor Peak flow Peak water Peak width rate level (m) velocity width rate level (m) velocity (m) (m 3 /s) (m/s) (m) (m 3 /s) (m/s) Unmitigated Current situation Mitigated Proposed A - At drain chainage 3,287m B – At extended culvert outlet 5 17.39 1.82 0.99 24 9.10 1.88 1.45 25 A 46.92 3.03 1.5 12 B 6.51 1.64 1.35 7.1.12 Stormwater Treatment Wetland The current Stormwater Treatment Wetland is owned by TCC and on land leased from MPBI. It is for the treatment of stormwater generated from residential areas within the Maranui catchment. This project will maximise the use of this area to treat and discharge stormwater generated by the TEM. In addition to this the wetland will be able to accommodate discharges from the MPBI industrial zoned land at Truman lane, and MPBI industrially zoned land between Truman Lane and the Mangatawa Drain. The final shape and design of the stormwater treatment wetland will be dictated by the developments that are proposed to use it. In this instance if the MPBI land is developed to its industrial zoned capacity, the pond needs to be enlarged beyond its lease area. An area that could be used is between SES13, the existing wetland, and the proposed MPBI development. If MPBI land remains undeveloped the pond will remain within the current TCC leased area. The design will be able to treat and discharge stormwater to accepted regional water quality levels. Detailed drawings and information of this wetland can be found in Appendix 10. • The total volume of earthworks required for NZTA TEM works in the proposed stormwater treatment wetland is approximately 4,500m³ - 5,500m 3 . This is the subject of this application. • The total volume of earthworks required for TCC works in the proposed stormwater treatment wetland is 16,000m³ - 20,000m 3 . This will be the subject of a future application. • The total volume of earthworks required for the MPBI portion of the stormwater treatment wetland is 17,000m³ - 24,000m 3 . This will be the subject of a future application. Status: Final Page 71 April 2009 Project Number: 3932036 NZ1-1552092-Mangatawa Drain Flood Bypass and TEM Stormwater AEE
NZ Transport Agency and Tauranga City Council Mangatawa Drain Flood Bypass and TEM Stormwater AEE Overall the total volume of earthworks required for the stormwater treatment wetland is approximately 45,400m 3 . In the future design of the wetland and staging of the works required the following principles have been agreed by TCC, NZTA and MPBI achieve an acceptable stormwater treatment area: 1. Maximise the use of the current lease area 2. Retain as much of the established trees and plants as possible 3. Not to encroach on the Special Ecological Site 13 located on the south of the treatment area 4. Be capable receiving and treat stormwater from TCC’s residential areas, MPBI proposed industrial land and the TEM 5. Not to encroach on the existing and proposed TCC pipeline easements along the western boundary 6. Apply ARC TP10 design standards for the upgrading of the wetland. The following Table shows the stormwater runoff for the water quality storm events and the percentage split between the various parties. Table 11: Stormwater Treatment Requirement Party Pervious area (km 2 ) Impervious area (km 2 ) Catchment area (km 2 ) Volume required (m 3 ) TCC 0.79 1.75 2.54 12,941 (Maranui and Arataki) MPBI 0.01 0.45 0.46 11,635 (Industrial) TEM 0.04 0.15 0.19 3,247 (Motorway) Total 0.84 2.35 3.19 27,823 The current available leased area is too small for the stormwater treatment required for all developed land scenarios as shown above. There is a potential 5 ha low lying area available east of the current pond area, enclosed between MPBI southern boundary and the Special Ecological Site. The additional treatment area extends into that land and is shown in the technical report attached as Appendix 10. The report shows the layout and cross-section drawings for the extended treatment area. Status: Final Page 72 April 2009 Project Number: 3932036 NZ1-1552092-Mangatawa Drain Flood Bypass and TEM Stormwater AEE
Page 1 and 2:
Mangatawa Drain Flood Bypass and TE
Page 3 and 4:
NZ Transport Agency and Tauranga Ci
Page 5 and 6:
Page 7 and 8:
Page 9 and 10:
Page 11 and 12:
Page 13 and 14:
Page 16 and 17:
Page 18 and 19:
Page 20 and 21:
Page 22 and 23:
Page 24 and 25:
Page 26 and 27:
Page 28 and 29: NZ Transport Agency and Tauranga Ci
Page 43: NZ Transport Agency and Tauranga Ci
Page 116: APPENDIX 1 - Drawing 3932036 ck301R
Page 120: APPENDIX 3 - Drawing 3932036 ck119
Page 126: APPENDIX 5 - Bioresearches Report:
Page 205 and 206:
APPENDIX 7 - Archaeological Assessm
Page 207 and 208:
ARCHAEOLOGY B.O.P. HERITAGE CONSULT
Page 209 and 210:
2 INTRODUCTION Project Background T
Page 211 and 212:
4 ARCHAEOLOGICAL LANDSCAPE Previous
Page 213 and 214:
6 U14/1708 & 1709 Figure 3. Cadastr
Page 215 and 216:
8 Figure 6. Part ML 8133 showing Pt
Page 217 and 218:
10 Hungahunga & Toroa A further ton
Page 219 and 220:
12 APRIL 2008 ARCHAEOLOGICAL SURVEY
Page 221 and 222:
14 Historic Places Act In addition
Page 223 and 224:
APPENDIX 8 - Hydraulic Modelling: M
Page 225 and 226:
Hydraulic Modelling: Mangatawa Drai
Page 227 and 228:
undertake investigations into the d
Page 229 and 230:
Discharge to Papamoa Beach To disch
Page 231 and 232:
• Riparian planting adjacent to t
Page 233 and 234:
2.2 Hydrological Assessment 2.2.1 C
Page 235 and 236:
The Maranui catchment area in the m
Page 237 and 238:
Table 7 - 2% AEP Storm Event Top Sp
Page 239 and 240:
These results include climate chang
Page 241 and 242:
3.3 Maintenance Work in Mangatawa D
Page 243 and 244:
stormwater from the Maranui catchme
Page 245:
Appendix A Mangatawa Drain Layout P
Page 249:
Appendix C Runoff Hydrographs
Page 255:
Appendix E Proposed Lower Mangatawa
Page 263:
APPENDIX 10 - Drawings 3932036 ck46
Page 272:
APPENDIX 12 - Drawing 3932036 ck227
Page 275 and 276:
Report Tauranga Eastern Motorway -
Page 277 and 278:
1 Introduction This report describe
Page 279 and 280:
embankment settlement rates, and th
Page 281 and 282:
3.2 Construction Sequence The typic
Page 283 and 284:
concrete contamination as well as s
Page 285 and 286:
Pahse 1 consists of the western sec
Page 287 and 288:
• Installation of Stage 2 decanti
Page 289:
Appendix A Erosion and Sediment Con
Page 295 and 296:
Activity Status Mangatawa Drain 1.1
Page 297 and 298:
(b) Natural State (River) Water Qua
Page 299 and 300:
6. Reclamation or drainage of the b
Page 301 and 302:
APPENDIX 15 - Legal Descriptions of
Page 303 and 304:
Path: P:\393\3932036\TGI\55_Project
Page 311 and 312:
32 Harington Street PO Box 903, Tau
Page 313:
32 Harington Street PO Box 903, Tau
show all

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

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?