Application of Physiographic Science to the Northland Region: Preliminary Hydrological and Redox Process-Attribute Layers Clint Rissmann, Lisa Pearson, Jessie Lindsay, Matt Couldrey and Abigail Lovett Land and Water Science Report 2018/11 June 2018 www.landwaterscience.co.nz Application of Physiographic Science to the Northland Region: Preliminary Hydrological and Redox Process-Attribute Layers Prepared by Rissmann, C., Pearson, L., Lindsay, J., Couldrey, M., and Lovett, A. Land and Water Science Ltd. www.landwaterscience.co.nz 61c Leet Street Invercargill, 9810 New Zealand Corresponding Author Clint Rissmann Contact number: 03 214 3003 Email: [email protected] Document Information Land and Water Science Report No: 2018/11 Report Date: 29.06.2018 Project Number: 18001-NRC Reviewed By: Susie Osbaldiston Organisation: Northland Regional Council Position: Groundwater Management Scientist Review Date: 12.06.2018 Document Status: Final Citation Advice Rissmann, C., Pearson, L., Lindsay, J., Couldrey, M., and Lovett, A. (2018). Application of Physiographic Science to the Northland Region: Preliminary Hydrological and Redox Process- Attribute Layers. Land and Water Science Report 2018/11. p88. Disclaimer: This report has been prepared by Land and Water Science Ltd. (Land and Water Science) exclusively for, and under contract to Northland Regional Council. Land and Water Science accepts no responsibility for any use of, or reliance on any contents of this report by any person or organisation other than Northland Regional Council, on any ground, for any loss, damage, or expense arising from such use or reliance. Information presented in this report is available to Northland Regional Council for use from 1 June 2018. Land and Water Science Report 2018/11 i Project Number: 18001-NRC Table of Contents List of Figures .............................................................................................................................. iv List of Tables ............................................................................................................................... vi Abstract ....................................................................................................................................... 1 1 Introduction ......................................................................................................................... 2 2 Background to Physiographic Science .................................................................................... 2 3 Northland Environmental Setting .......................................................................................... 8 3.1 Climate and Hydrology ............................................................................................................ 9 3.2 Geology ................................................................................................................................... 9 3.3 Hydrogeology .......................................................................................................................... 9 3.4 Soils ....................................................................................................................................... 10 4 Input data .......................................................................................................................... 11 4.1 Geospatial ............................................................................................................................. 11 4.2 Surface water data ................................................................................................................ 12 4.3 Groundwater data ................................................................................................................. 15 5 Water Composition and General Characteristics .................................................................. 17 5.1 Redox Assignment ................................................................................................................. 17 5.2 Multivariate Analysis - Combined SW and GW ..................................................................... 24 5.2.1 3-Cluster waters ............................................................................................................ 26 5.2.2 4-Cluster waters ............................................................................................................ 27 5.2.3 7-Cluster waters ............................................................................................................ 30 5.2.4 Water Chemistry Summary ........................................................................................... 36 5.3 Land Use ................................................................................................................................ 36 6 Hydrological Process-Attribute Layer ................................................................................... 41 6.1 Introduction .......................................................................................................................... 41 6.2 Hydrological Domain: Water Source and Recharge Mechanism .......................................... 42 6.2.1 Application to Northland .............................................................................................. 42 6.2.2 Hydrological Domain Map ............................................................................................ 44 6.3 Flow Path Analysis................................................................................................................. 49 6.3.1 Application to Northland .............................................................................................. 49 6.3.2 Overland Flow Layer ..................................................................................................... 50 6.3.3 Lateral and Artificial Drainage Layers ........................................................................... 55 6.3.4 Deep Drainage Layer ..................................................................................................... 59 6.4 Summary of Hydrological Layers (H-PAL) and Recommendations ....................................... 62 7 Redox Process-Attribute Layer ............................................................................................ 64 7.1 Introduction .......................................................................................................................... 64 7.2 Application to Northland ...................................................................................................... 65 Land and Water Science Report 2018/11 ii Project Number: 18001-NRC 7.2.1 Redox State ................................................................................................................... 65 7.2.2 Correlation .................................................................................................................... 69 7.3 Soil Reduction Potential Map ............................................................................................... 70 7.4 Geological Reduction Potential Map .................................................................................... 73 7.5 Combined Redox Process Attribute Layer (R-PAL) ................................................................ 76 7.6 Summary of Redox Layer (R-PAL) and Recommendations ................................................... 79 8 Concluding Comments ........................................................................................................ 80 9 Acknowledgments .............................................................................................................. 80 10 References ......................................................................................................................... 81 Appendix 1. Correlation Matrix ............................................................................................... 88 Land and Water Science Report 2018/11 iii Project Number: 18001-NRC List of Figures Section 2 Figure 2. 1: Illustration of the connectivity of near-surface water resources, including soil water, surface and shallow groundwater (Hughes et al., 2016). Green tick marks show the hydrologically connected settings included in the physiographic approach, whereas red crosses identify settings that are excluded. ................................................................................................................................... 3 Figure 2. 2: Summary of steps to develop the physiographic mapping method (Rissmann et al. 2018a). .................................................................................................................................................... 4 Section 4 Figure 4. 1: Northland surface water quality monitoring sites and associated capture zones. Sites with State of Environment (SOE) data and PENZ test set are shown in red and sites with SOE data only are shown in yellow (See Table 5.1 for site names). ..................................................................... 13 Figure 4. 2: Northland groundwater quality monitoring sites (purple) in relation to surface water capture zones (See Table 5.2 for site names). ...................................................................................... 16 Section 5 Figure 5.1. Cumulative probability plot of Dissolved Oxygen (DO, mg/L) for Northland groundwater. Four key inflection points (arrows) and five (V) DO populations are identified. Individual sample values, not site medians are used. DO