Hawke’s Bay Regional Council – Regional Assets Section APPLICATION TO EXTRACT GRAVEL FROM THE NGARURORO RIVER October 2017 i TABLE OF CONTENTS Part A: Application for Resource Consent Part B: Assessment of Effects on the Environment 1. Introduction ___________________________________________________________ 1 1.1 Background 1 1.2 Report Structure 2 1.3 Supporting Documents 3 1.4 Definitions and Abbreviations 4 2. Existing Environment ___________________________________________________ 5 2.1 Overview 5 2.2 Flood Protection 8 2.3 Historic and Current River Gravel Management 8 2.4 Riparian Land Use 10 2.5 Water Quality and Aquatic Ecology 15 2.6 Terrestrial Ecology 16 3. Description of the Proposed Activity _______________________________________ 16 3.1 Concept 16 3.2 Extraction Locations 17 3.3 Extraction Volumes and Timing 19 3.4 Restrictions During Nesting Seasons 21 3.5 Extraction Contractors 22 3.6 Gravel Extraction Methodology 22 3.7 Effects Avoidance and Mitigation Measures 24 3.8 Proposed Consent Conditions 26 3.9 Consent Term 26 4. Assessment of Environmental Effects _____________________________________ 26 4.1 Positive Effects 26 4.2 Sustainability of the Gravel System Resource 27 4.3 Effects on Water Quality 31 4.4 Effects on Aquatic Animals 31 4.5 Effects on Riverbed Birds 34 4.6 Invasive Vegetation 35 4.7 Effects on Coastal Sediment Supply 35 4.8 Effects on Cultural and Spiritual Values 36 4.9 Effects on Amenity 37 4.10 Effects on Infrastructure 38 4.11 Efeects On Water Takes 38 5. Planning Assessment __________________________________________________ 38 5.1 Resource Consent Required 39 5.2 Statutory Considerations 42 Application to Extract Gravel from the Ngaruroro River 6. Consultation __________________________________________________________ 61 7. Conclusion __________________________________________________________ 62 References __________________________________________________________ 64 LIST OF FIGURES Figure 1: Definitions of terms relating to the braided river channel Figure 2: Locality Plan Figure 3: Location Plan Figure 4: Typical section of braided river channel between Whanawhana and SH50. Note stopbank at right of photo Figure 5: Historic gravel extraction from the Ngaruroro River (source HBRC) Figure 6: TANK catchments Figure 7: Land cover for Ngaruroro and Tutaekuri River Catchments Figure 8: Vegetation Cover Figure 9: Public Access Points Figure 10: Proposed reach of Ngaruroro River within which gravel extraction may occur (shown in blue). Figure 11: Ngaruroro River historic production and future demand growth, for low (upper) and medium to high (lower) growth scenarios (from Stevens and Larsen 2015) Figure 12: Riverbed management zones Figure 13: Typical gravel extraction operations Figure 14: Typical gravel extraction operations showing works bunded from main river on far left (adjacent to willow trees). Figure 15: Ngaruroro River sectional gravel volumes LIST OF TABLES Table 1: RRMP Section 6.8.3 River Control & Drainage Works & Structures Table 2: RRMP Section 6.8.5 River Bed Gravel Extraction Application to Extract Gravel from the Ngaruroro River APPENDICES A: Gravel Extraction Area – Ngaruroro River B: Suggested Consent Conditions C: Hawke’s Bay Regional Council Application Forms (A & B) D: Environmental Code of Practice for River Control and Waterway Works (Draft) E: Terrestrial Ecology Impact Assessment (Forbes Ecology) F: Effects on Instream Species in Hawke’s Bay Rivers (Cawthron Institute) G: Hawke’s Bay Riverbed Gravel Management Plan H: Sediment Supply Context (HBRC Regional Assets Section) I: Location of Consented Water Takes within Ngaruroro River REPORT INFORMATION Report Status Final (Revised October 2017) Our Reference 30034N File Location Taupo Author Jeremy Williams David Ray Review By Simon Bendall © Mitchell Daysh Limited (2017). This document and its contents are the property of Mitchell Daysh Limited. Any unauthorised employment or reproduction, in full or in part, is forbidden. Application to Extract Gravel from the Ngaruroro River PART A Application for Resource Consent FORM 9 APPLICATION FOR RESOURCE CONSENT Section 88 Resource Management Act 1991 To Hawke’s Bay Regional Council Private Bag 6006 Napier 4142 1. Hawke’s Bay Regional Council (Regional Assets section) applies for new resource consent as described below. 2. The activity to which the application relates (the ‘proposed activity’) is: To extract gravel (defined as gravel and associated sand, silt and other riverbed sediments) from the Ngaruroro River bed, comprising the active river channel and berms, for the purposes of maintaining the design channel capacity and the alleviation of flood and erosion risk. The volume to be extracted each year shall be based on: a) Calculation and comparison of mean bed levels and reach volumes between cross sections and between 3 yearly surveys b) Comparison of mean bed levels and reach volumes with bed level design grade lines c) Based on (a) and (b), an assessment of the sustainable gravel extraction for the current year. 3. The site at which the proposed activity is to occur along with the relevant legal descriptions are as follows: HBRC seeks consent for the extraction of gravel from the Ngaruroro River in the locations highlighted in blue in Appendix A to this application, which is from the coast to map reference NZTM 1892902.293 east, 5615066.873 north (approximately 6.4 km west of the intersection of Matapiro and Whanawhana Roads). 4. The land/site is owned by the Crown and administered by the Hawke’s Bay Regional Council. 5. I attach: a) in accordance with the Fourth Schedule of the Resource Management Act 1991, an assessment of environmental effects (as Part B of this document) in the detail that corresponds with the scale and significance of the effects that the proposed activity may have on the environment. b) an assessment of the proposed activity against the matters set out in Part 2 of the Resource Management Act 1991, and c) a discussion of the matters specified in Rule 74 of the Regional Resource Management Plan (RRMP) and Rule 61 of the Regional Coastal Environmental Plan (RCEP) Application to Extract Gravel from the Ngaruroro River 6. I attach an assessment of the proposed activity against any relevant provisions of a document referred to in section 104(1)(b) of the Resource Management Act 1991, including the information required by clause 2(2) of Schedule 4 of that Act. 7. The applicant seeks a consent duration of 25 years. Dated this 11th day of July 2017. Signature: Hawke’s Bay Regional Council by their duly authorised agents Mitchell Daysh Limited. _______________________ Jeremy Williams Senior Planner Address for Service: Contact Applicant Agent Organisation: Hawke’s Bay Regional Council Mitchell Daysh Ltd C/O: Gary Clode Jeremy Williams Address: Private Bag 6006 PO Box 245 NAPIER 4142 TAUPO 3351 Landline: (06) 835 9200 (07) 378 1791 Mobile: - 021 1468 556 Email: [email protected] [email protected] Please contact both the applicant and agent representatives on all relevant correspondence relating to the application for resource consent. Application to Extract Gravel from the Ngaruroro River PART B Assessment of Effects on the Environment 1. INTRODUCTION 1.1 BACKGROUND Historically, the Hawke’s Bay rivers draining the Ruahine, Kaimanawa, and Kaweka Ranges have transported large volumes of greywacke gravels and other sediments from those ranges, depositing it onto alluvial plains to the east of the ranges. This sediment transport process resulted in the rivers meandering across the alluvial plains over time as braided and semi-braided river channels. During the second half of the 20th century, flood protection schemes were established to protect rural and urban development from flooding from these rivers. The Hawke’s Bay Regional Council – Regional Assets Section (HBRC1) has the responsibility for managing these schemes. An important component of the schemes is a series of stopbanks, which contain floodwaters within a defined ‘floodway’. The stopbanks and other flood protection assets (such as riparian planting and other erosion protection works) have confined the braided rivers to the floodway, which is typically 100 to 250 metres wide, depending on the river reach. The floodway is designed to safely convey a design flood event, which requires the floodway to have a minimum width and depth at any particular location so that the floodwaters can pass through the floodway without overtopping or compromising the stopbanks. The rivers continue to transport gravel and sediments from the ranges into the braided river channels. Major flood events move these sediments through the system, while at the same time bringing more material down from the ranges. Partly due to impacts of uplift caused by the 1931 Hawke’s Bay Earthquake, partly because the braided channels no longer meander across the plains, and partly because any significant movement of gravel relies on intermittent and unpredictable flood events, sediment can build up in some locations, raising the bed level and reducing the channel capacity between the river bed and the top of the stopbanks. This reduces the flood protection provided by the stopbanks and can raise water tables, making it difficult to manage adjacent farmland. If this sediment build-up was allowed to continue without intervention, the stopbanks would eventually be overtopped during large flood events. Localised aggradation can also cause river meanders to switch from a preferred tangential flow alignment into a more