1. STATEMENT OF PRIMARY EVIDENCE OF Richard Goodwin Storey
ON BEHALF OF WELLINGTON REGIONAL COUNCIL

2. Evidence for these matters:
Assessment of
the relationship between dissolved nutrients and MCI values in Wellington streams and rivers.
and
setting region-wide nutrient limits as a means for meeting target MCI values in Wellington streams and rivers.

3. Scope of evidence
Assessment of submissions relating to nutrient management for achieving target MCI values in Wellington streams and rivers
Alternative methods for achieving target MCI values

4. Issues raised in the evidence of Dr. Russell Death
Validity of the correlations between MCI and nutrients in datasets containing modelled data only.
The strength of correlations using measured values of MCI and nutrients.
Lack of consideration of other factors likely to influence MCI values in addition to nutrients, particularly in urban catchments.
Lack of consideration of the pathway by which nutrients may affect MCI, and what other factors may influence this pathway.
Appropriateness of nitrate and dissolved reactive phosphorus as the most relevant measures of available nitrogen and phosphorus, respectively
Applying a single relationship between MCI and dissolved nutrients to all stream types in the region.
The implied assumption that MCI will improve when a stressor is reduced.

5. Accident rate Colour of car Average age of driver Colour of car 60 4020 40 60
Colour of car

6. Issues raised in the evidence of Dr. Russell Death
Validity of the correlations between MCI and nutrients in datasets containing modelled data only.
The strength of correlations using measured values of MCI and nutrients.
Lack of consideration of other factors likely to influence MCI values in addition to nutrients, particularly in urban catchments.
Lack of consideration of the pathway by which nutrients may affect MCI, and what other factors may influence this pathway.
Appropriateness of nitrate and dissolved reactive phosphorus as the most relevant measures of available nitrogen and phosphorus, respectively
Applying a single relationship between MCI and dissolved nutrients to all stream types in the region.
The implied assumption that MCI will improve when a stressor is reduced.

7. From Matheson et al. (2015)

8. From Matheson et al. (2015)

9. Source: Clapcott et al. (2011) Sediment Assessment Methods

10. Max annual periphyton cover in Ruamahanga SoE sites

11. Issues raised in the evidence of Dr. Russell Death
Validity of the correlations between MCI and nutrients in datasets containing modelled data only.
The strength of correlations using measured values of MCI and nutrients.
Lack of consideration of other factors likely to influence MCI values in addition to nutrients, particularly in urban catchments.
Lack of consideration of the pathway by which nutrients may affect MCI, and what other factors may influence this pathway.
Appropriateness of nitrate and dissolved reactive phosphorus as the most relevant measures of available nitrogen and phosphorus, respectively
Applying a single relationship between MCI and dissolved nutrients to all stream types in the region.
The implied assumption that MCI will improve when a stressor is reduced.

13. Scope of evidence
Assessment of submissions relating to nutrient management for achieving target MCI values in Wellington streams and rivers
Alternative methods for achieving target MCI values