5 Surface Water Quality
5 SURFACE WATER QUALITY...... 56
5.1 SURFACE WATER QUALITY: MAIN POINTS ...... 57 5.2 INTRODUCTION TO SURFACE WATER QUALITY IN NORTHLAND ...... 59 5.3 REGIONAL POLICY STATEMENT OBJECTIVES ...... 59 5.4 SURFACE WATER QUALITY ISSUES ...... 59 5.5 PRESSURES AFFECTING SURFACE WATER QUALITY ...... 61 5.5.1 Point-Source Discharges...... 61 5.5.2 Non-Point Source Discharges ...... 68 5.5.3 Water Pollution Incidents...... 70 5.5.4 Riparian Vegetation...... 71 5.6 STATE OF SURFACE WATER QUALITY...... 72 5.6.1 Are Northland’s Rivers and Streams Suitable for Swimming? ...... 72 5.6.2 Are Northland’s Rivers and Streams Suitable for Aquatic Life? ...... 74 5.6.3 Are Northland’s Rivers and Streams Suitable for Stock Water/Irrigation?...... 77 5.7 STATE OF FRESHWATER ECOSYSTEMS ...... 79 5.7.1 Stream Macroinvertebrates ...... 79 5.7.2 Freshwater Fish...... 82 5.8 RESPONSE TO SURFACE WATER QUALITY ISSUES...... 84 5.8.1 Northland Regional Council...... 84 5.8.2 Other Responses ...... 85
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Northland Regional Council State of the Environment Report 2002
5.1 Surface Water Quality: Main Points
Pressures