30th August 2016
Latest update/ panui on the collaborative group of stakeholders developing the Regional Plan to manage land and water in the Tutaekuri, Ahuriri, Ngaruroro and Karamu catchments - TANK.
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At its last meeting on 9 August, the TANK Group looked at water quality information for the Tutaekurī River, as well as further information for the Ngaruroro River.

The Group is starting to get a feel for the overall state of these rivers and their tributaries and what it means for the multiple values they will be managed for, i.e. recreation, human health, ecosystem health, economic and asset use, etc
Discussion centred on:
  • how well the current state provides for the values, and
  • how important or urgent it is to find a management response to address concerns about particular attribute states.

Figure 1: The upper Ngaruroro is a widely braided river.

National Guidelines
Both the Ngaruroro and Tutaekurī meet all the national bottom line requirements in the NPSFM (National Policy Statement for Freshwater Management) for quality.  However, there are concerns about some of the attribute states for tributaries of both these main rivers.  There are also concerns about sediment (water clarity and deposited sediment) in the lower reaches of both the main rivers and many of the tributaries.
TANK Member Profile: Phil Holden
Vineyards Manager-Gimblett Gravels

I have been actively involved in growing fruit crops in Hawkes Bay for 33 years. I have been with Villa Maria for 17 years managing a group of Vineyards.
As we can no longer assume access to water I have committed to this process. We aim to maintain or improve water quality while retaining the economic benefits for this region that are derived from the careful use of water.
Water Quality and Sediment
WATER CLARITY is a measure of particles in the water; it especially includes sediment.  Sediment in the water and deposited on the bed adversely affects fishery values, the health of macro-invertebrates and the value of a river for a range of recreational activities.  Sediment will also enter estuaries and the coastal marine area and affect a range of values in those areas too.  More information about sediment sources and mitigation measures will be considered by the Group at the next meeting in September.
Figure 3: Examples of Macroinvertebrates

MCI – Macro Invertebrate Index
MCI is a measure of the health of the river and is a score based on types of macro-invertebrates (aquatic insects) in the waterway.   MCI will vary naturally according to the type of river and where in the catchment MCI is measured.  There is research underway to compare measured MCI with what could be expected, to see what opportunities there are for improving MCI.  The Group indicated that improvements in MCI could be looked into for a range of sites including the Ngaruroro at Fernhill and the motorway, and the Tutaekurī at Puketapu and Brookfields Bridge. The Ohiwa, Waitio and Tutaekurī-Waimate also had lower MCI scores that the TANK Group
wished to see addressed. But these scores may also be influenced by the soft-bottomed nature of these tributaries.
Dissolved Nutrients
The main rivers have generally low DISSOLVED NUTRIENTS, although the Tutaekurī levels are slightly elevated.  Dissolved phosphorus is quite high in some of the tributaries and dissolved nitrogen is also elevated.  These nutrients in combination with flow, substrate and temperature and can cause algae to grow more quickly and affect the types of algae that grow.  The relationship between all of these factors on algae, including phormidium growth can be very complex
Figure 2: Numbers of Macroinvertebrates across the TANK catchments
ALGAE levels in the Mangatutu and Maraekakaho can occasionally exceed guidelines for recreation and phormidium (a type of algae that sometimes includes toxic strains) and can be high in the Poporangi and Mangatutu Rivers.  The lower reaches of the Tutaekurī can also exceed algae guidelines for recreational values.  The TANK Group wishes to focus on algae management in these areas.

E. coli
The management of E. COLI levels in relation to swimming and other values including those of tāngata whenua continues to be of concern for the Group.  The need for water to be clean for mahinga kai values was discussed, and although washing or cooking food before eating it reduces contamination, the need for water quality to be free of significant bacteria was identified as important.
E.coli levels in the main rivers and most of the tributaries meet the quality required for swimming nearly all of the time.  However, while the Ohiwa and Tutaekurī-Waimate rivers meet the standards required for secondary contact (such as kayaking) and for stock drinking water, they don’t meet swimming water quality requirements.  E. coli in urban streams has also been raised as a potential concern although no data has been received so far by the TANK Group.  Further work on this is being carried out by the Stormwater Working Group.

Waitangi Estuary
The TANK Group will consider the state and trend of the Waitangi estuary health in relation to deposited sediment and nutrients at its next meeting, and are aware of the need to take these aspects into consideration.   
NOTE: we want profiles for each newsletter - email a brief bio and photo to to help us show the varied perspectives of TANK Group. 
Please pass this newsletter/ panui on to anyone you think might benefit from it.
Got any comments or questions about this newsletter? Email Mary-Anne Baker
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