Volume One 15. Resource Quality (Water, Air, Soil) some Marlborough groundwaters have high levels of naturally occurring contaminants such as salt, iron and arsenic. There is also potential for bacteria from the faeces of feral animals (e.g. goats, pigs and possums) and other wildlife to contaminate fresh and coastal waters. Occasionally, natural processes will result in sediment reaching both fresh and coastal water, particularly during rainfall events. This affects the clarity and turbidity of water and the resulting dirty waters can have an impact on freshwater and marine life. Combinations of the threats described above can occur within the same catchment, creating the potential for cumulative adverse effects on freshwater and coastal water quality. Some coastal waters and waterbodies are more susceptible to water quality degradation than others. For example, the enclosed nature of the coastal waters in the Marlborough Sounds renders this water particularly sensitive to contamination, as dilution and tidal flushing is limited. Unmodified rivers, lakes and wetlands are also particularly vulnerable to the discharge of contaminants. Other coastal waters or waterbodies may have significant values that warrant special protection. There has been a strong preference for discharges to land since the first Marlborough Regional Policy Statement (MRPS) became operative in 1995. This has resulted in a reduction in the number of point source discharges to water. Consequently, the greatest risk to water quality is probably associated with non-point source discharges. Non-point source discharges are difficult to manage as there is no discrete point to which management can be applied. This situation does not justify inaction, but means that the management of non-point source discharges is challenging and will require innovative approaches. It is important that the MEP provides a framework to deal with the point source and non-point source discharges to maintain and enhance water quality in Marlborough’s coastal waters, rivers, lakes, wetlands and aquifers. Issue 15B – Water quality in some of Marlborough’s rivers has already been degraded, to the extent that their ability to support aquatic ecosystems and/or contact recreation has been compromised. Monitoring of water quality as part of the Council’s State of the Environment monitoring programme has established that water quality has become degraded in some rivers, relative to the natural and human use values that these rivers support or have supported in the past. Of particular note are changes in nutrient (nitrate and phosphorus), sediment and bacteria levels. Increasing levels of these contaminants is indicative of the impact of point source and non-point source discharge to rivers. These discharges have reduced the ability of the rivers to safely support primary contact recreation (i.e. swimming) and aquatic ecosystems. This is a significant concern given the contribution that water-based recreation makes to community wellbeing and the intrinsic values of aquatic ecosystems. Water quality degradation is measured relative to the attribute values provided by the National Objectives Framework included in the NPSFM and/or the Council’s water quality index. The water quality index, based on the Canadian Water Quality Index, summarises monthly measurements of nine chemical and physical parameters to produce an aggregate score for the state of water quality in Marlborough’s rivers. The score allows the overall state of water quality to be categorised as excellent, good, fair, marginal and poor, relative to the natural or desirable level. The rivers determined to be degraded (poor or marginal in the index) or at risk of degradation (close to marginal in the index) on the basis of the Council’s 2014/15 State of the Environment Report are identified in Tables 15.1 and 15.2 below. 15 – 5