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Calculating your CHI Scores

Carrying out interviews and field work will produce a large amount of data. For example, if six team members have assessed thirty sites, 180 forms will need to be analysed. The coordinator should calculate the CHI scores. A worksheet (provided in Appendix 6a) is one way of entering and then analysing the data. All the data needed to calculate the CHI score has either been collected as part of the interview process or can be found on the forms that have been collected from the field team.

Component 1 – Site status

Here the significance of the site to tangata whenua is assessed as well as the distinction between traditional and contemporary sites.

The first question can be answered when the sites are first selected, i.e. before the fieldwork. Sites are classified as:

A an area of traditional significance to tangata whenua; or

B an area not recognised by tangata whenua as being of traditional importance but which has been included in the CHI study to enable the entire river to be included or other aspects to be considered (for example it could be a site monitored by the regional council).

The second question on the field assessment form asks whether tangata whenua would return to the site in the future. Yes (1) indicates the belief that traditional uses can be sustained.

1 Tangata whenua would return to the site and use it as it was used in the past.

0 Tangata whenua would not return to the site and use it as it was used in the past.

When answers to the two questions are collated there are four possible combinations:

A–1
A–0
B–1
B–0
This is a traditional site, that tangata whenua would return to and use as they did in the past. This is a traditional site that tangata whenua would not return to. It would not be used in the future. This is a site that is not of traditional significance to tangata whenua. However, they would go to the site in future. This is a site that is not of traditional significance to tangata whenua. Further, they would not go to the site in future.

Component 2 – Mahinga kai

Here the mahinga kai values of a site are assessed – i.e. the food and other resources present.

There are four parts to the mahinga kai aspect of the Index. Each of the four elements receives a score of 1 to 5. The scores are then added together and averaged to give an overall mahinga kai measure for each site.

Element 1: Identification of mahinga kai species present at the site

While in the field a collated list of plant, bird and fish species is prepared for each site. A score of 1–5 is then made, depending on the total number of species present.

To assign a 1 to 5 score for each site, you need to identify the one site in the catchment that out of all your chosen sites has the largest number of species present. The number of species at this site will affect which grading is given to all the other sites.

Refer to the table in Appendix 5 to see how the 1 to 5 scores are assigned.

Example 1

Site 27 in a catchment has a collated total of 15 species, the largest number of species present compared to all the other sites visited in the catchment.

Table 1, under ‘Maximum 15’, shows the scores that will be made for each site in the catchment, according to how many species are present:

Maximum 15
1–3 species present scores 1
4–7 species present scores 2
8–10 species present scores 3
11–14 species present scores 4
15 + species present scores 5

 

Site 27 (15 species) gets a score of 5, site 28 (9 species) gets a score of 3, site 29 (5 species) scores 2.

Example 2

On a different river, site 12 has 9 different species, the highest number of species at a site in that catchment.

Under the column ‘Maximum 9’ in Table 1, the scores for sites will be:

Maximum 9
1–2 species present scores 1
3–4 species present scores 2
5–6 species present scores 3
7–8 species present scores 4
9 + species present scores 5

 

Site 12 (9 species) gets a score of 5, site 13 (4 species) scores a 2, site 14 (7 species) scores 4.

Element 2: Comparison of species present today and mahinga kai species historically sourced from the site

A score of 1 to 5 is assigned based on the number of species of traditional significance that are still present:

1 Non–traditional site.

1 None of the species sourced in the past are still present at the site.

2 Less than half the species sourced in the past are still present.

3 At least half of the species sources in the past are still present.

4 More than half the species sourced in the past are still present.

5 All species sourced in the past are still present at the site.

Element 3: Accessibility of the site

A score of either 1, 3 or 5 is given based on the legal and physical access tangata whenua have to the site:

1 No access to the site.

3 Either physical or legal barriers make access difficult.

5 Unimpeded easy access to the site.

Element 4: Whether tangata whenua would return to the site

A score of either 1 or 5 is given depending on whether tangata whenua would return to the site in future to use it as they did in the past to gather mahinga kai:

1 No, would not return to the site in future for mahinga kai gathering.

5 Yes, would return to the site in future for mahinga kai gathering.

The four mahinga kai elements are then averaged to produce a single mahinga kai score out of 5.

For example, the four scores for site 6 were 3, 1, 5, 5.

The total of 14 is divided by 4 to give an overall mahinga kai score of 3.5.

Component 3 – Cultural stream health

Here the health of the waterway according to eight indicators is assessed.

The eight indicators were identified from analysis of stream health data generated from all 107 sites on the Taieri, Kakaunui, Hakatere (Ashburton) and Tukituki Rivers. The method of selecting and refining the indicators is described in the technical report that was compiled to accompany these guidelines [Tipa and Teirney (February 2006). A Cultural Health Index for Streams and Waterways: a tool for nationwide use.] .

The description of Component 3 includes an explanation of the eight indicators and the field assessment form (Appendix 4) provides a guide to the 1–5 ratings for each indicator. Apart from this, further detail on the cultural stream health indicators and how they are rated needs to be the focus of training for the team.

All eight indicators are scored from 1 to 5 by each team member. In the analysis phase the coordinator needs to calculate the average score given by members of the team for each indicator by using the worksheet provided in Appendix 6A.

For each indicator add all the scores together to produce a total, and then divide by how many scores there are. This produces an average score for each indicator.

For example, for water clarity if the six team members gave the following scores – 2, 3, 2, 3, 2, 3, 2, 2 – then the average score for water clarity would be 2.37:

Step 1. Add 2+3+2+3+2+3+2+2 = 19

Step 2. Divide by 8 (19 ÷ 8 = 2.37).

Once average scores have been calculated for each of the eight indicators, add them together and average them to obtain the overall Cultural Stream Health Measure score.

For example, if the scores are as follows:

1. Catchment land use
2.3
2. Riparian vegetation
3.0
3. Use of riparian margin
2.5
4. Riverbed condition/sediment
4.6
5. Channel modification
2.9
6. Flow and habitat variety
3.6
7. Water clarity
4.2
8. Water quality
4.1
Total:
27.2
Divide 27.2 by 8 =
3.4

The Cultural Stream Health Measure score is 3.4.

Overall CHI score

The overall three–part Cultural Health Index is expressed as a string, as shown in the following example.

A–0
3.5
3.4
A: identifies the site as traditional Mahinga kai score Stream health score
0: identifies that the site will not be used in the future 1 = poor mahinga kai values 1 = poor stream health
  2.5 = average mahinga kai values 2.5 = average stream health
  5 = excellent mahinga kai values 5 = excellent stream health

Examples of analysing a Cultural Health Index score

Some examples of the CHI scores are set out below. They have been obtained for 10 sites in the Taieri, Kakaunui, Hakatere (Ashburton) and Tukituki catchments.

Stream health indicators (the third component of the index) have varied in number and nature between the rivers studied in the development of the CHI. The Taieri and Kakaunui feature five indicators, as does the Hakatere, but for the Taieri two of the five indicators are different. The stream health of the Tukituki was assessed by only two indicators. These differences are seen in the following examples of CHI scores.

In the most recent development of the Cultural Health Index these various indicators have been integrated to produce one set of eight cultural stream health indicators for national use of the CHI. [The process of developing the cultural stream health indicators is described in the technical report that was compiled to accompany these guidelines.]

Taieri Catchment

Site 1: McRaes Creek (B–1 / 2.69 / 4.87)

The assessment confirmed that:

  • This is not a traditional site.
  • Despite this, rūnanga members would return to the site.
  • Its mahinga kai values are only average.
    • It receives an average score for access. It is accessible although it involves a significant walk.
    • There is a reasonable range of mahinga kai species present, especially plants. However, this is a small tributary and there are not many fish species present.
    • This is not a traditional site and therefore species sourced traditionally cannot be compared with those present today. Accordingly a 1 was assigned to this part of the mahinga kai component.
    • It scores highly because rūnanga members would return to the site.
  • It scores very highly for component 3 stream health – 4.87. In fact McRaes Creek received the highest ratings of all 46 sites in the Taieri and Kakaunui catchments:
    • Catchment land use – 4.6
    • Channel modification – 4.75
    • Use of the riparian margin – 5
    • Flow visible – 5
    • Water quality – 5

The slightly lower score for catchment land use reflects the presence of some exotic species within a native catchment. The score for channel modification reflects the presence of a track through the watercourse that is used by mountain bikes and motorbikes.

Site 6: Barbours Stream (B–0 / 1.3 / 3.02)

The assessment confirmed that:

  • This is not a traditional site.
  • Because of the degraded condition of the site, rūnanga members would not return to the site.
  • Its mahinga kai values are poor.
    • It scores poorly for access. It was difficult for rūnanga members to find this site without assistance.
    • Mahinga kai species were absent.
    • This is not a traditional site and therefore species sourced traditionally cannot be compared with those present today. Accordingly a 1 was assigned to this part of the mahinga kai component.
    • It only scores 1 because rūnanga members would not return to the site.
  • It received an average score for stream health:
    • Catchment land use – 2.5
    • Channel modification – 2.6
    • Use of the riparian margin – 1
    • Flow visible – 5
    • Water quality – 4

The low scores for catchment land use, river modification and use of the riparian margin results from this site being heavily modified by stock. In particular, the riparian margin was considered to be in poor condition. Despite this, the flow and water quality received exceptional ratings, possibly because of the tussock in the catchment.

Site 11: Owhiro Creek (A–0 / 1.75 / 1.65)

The assessment confirmed that:

  • This is a traditional site.
  • Rūnanga members would not return to the site.
  • Its mahinga kai values are low.
    • It receives a high score for access.
    • Because the site is so modified, there is an absence of mahinga kai species, aside from eel.
    • It scores highly because it was traditionally a significant site for eels and these are still present.
  • It scores poorly because rūnanga members would not return to the site.
  • It scores very poorly for stream health, in fact it was one of the two poorest scoring sites for this component among the Taieri and Kakaunui sites:
    • Catchment land use – 1
    • Channel modification – 1
    • Use of the riparian margin – 1
    • Flow visible – 4
    • Water quality – 1.25

All scores apart from a visible flow are very low.

Kakaunui Catchment

Site 38: Island Stream - Maheno (A–0 / 2.56 / 1.06)

The assessment confirmed that:

  • This is a traditional site.
  • Rūnanga members would not return to the site.
  • Its mahinga kai values are only average.
    • It receives a high score for access. It is easily accessible.
    • There is a limited range of mahinga kai species present.
    • It scores highly because it was a significant eel fishery and has the highest density of eels within the Taieri and Kakaunui catchments.
    • It scores poorly because rūnanga members would not return to the site.
  • It scores very poorly for stream health:
    • Catchment land use – 1
    • Channel modification – 1.3
    • Use of the riparian margin – 1
    • Flow visible – 1
    • Water quality – 1

The consistently low scores for each of the indicators confirm the poor health of this site, the worst of the Taieri and Kakaunui study sites.

Hakatere Catchment

Site 1: Gentleman Smith (A–1 / 4.25 / 3.80)

The assessment confirmed that:

  • This is a traditional site.
  • Because of the healthy condition of the site, rūnanga members would return to the site.
  • Its mahinga kai values are exceptional.
    • It scores highly for access. It was easy for rūnanga members to access this site without assistance.
    • A reasonable range of mahinga kai species were present.
    • This is a traditional site and all the species sourced traditionally are present today. Accordingly a 5 was assigned to this part of the mahinga kai component.
    • It scores 5 because rūnanga members would return to the site in the future.
  • It received a score of 3.8 for stream health that was made up of lower scores for out of the river indicators and higher scores for in the river indicators.
    • Catchment land use – 2.33
    • Channel modification – 3.33
    • Water clarity – 4.66
    • Riverbed condition – 4.5
    • Water quality – 4.16

Of the 30 sites assessed in the Hakatere, this site scored the highest for component 2 – mahinga kai values.

Site 3: Lambies Stream (B–0 / 2.0 / 3.13)

The assessment confirmed that:

  • This is not a traditional site.
  • Rūnanga members would not return to the site.
  • Its mahinga kai values are only average.
    • It receives an average score for access.
    • There is a limited range of mahinga kai species present.
    • This is not a traditional site and therefore species sourced traditionally cannot be compared with those present today. Accordingly a 1 was assigned to this part of the mahinga kai component.
    • It scores poorly because the majority of rūnanga members would not return to the site.
  • It receives above average scores for stream health:
    • Catchment land use – 2.3
    • Channel modification – 3.66
    • Water clarity – 3.16
    • Riverbed condition – 3.33
    • Water quality – 3.16

Site 9: Bowyers Stream – Sharplin Falls (A–1 / 3.25 / 4.87)

The assessment confirmed that:

  • This is a traditional site.
  • Rūnanga members would return to the site.
  • Its mahinga kai values are above average.
    • It receives a high score for access.
    • Because the site is unmodified, there is a good range of mahinga kai species present.
    • It scores poorly because it was traditionally a significant site for eels and there are no eels currently present.
    • It scores highly because rūnanga members would return to the site.
  • An exceptional score was awarded for stream health:
    • Catchment land use – 4.5
    • Channel modification – 5
    • Water clarity – 5
    • Riverbed condition – 4.83
    • Water quality – 5

Of the 30 sites assessed in the Hakatere catchment this site received the highest score for stream health. In fact the Sharplin Falls site was among the most highly rated streams sites in the study.

Tukituki Catchment

Site 2: Mangaomate Stream (B–1 / 2.72 / 3.75)

The assessment confirmed that:

  • This is not a traditional site.
  • Because of the healthy condition of the site, iwi members would return to the site.
  • Its mahinga kai values are average.
    • It scores average for access. It was easy for iwi members to access this site without assistance.
    • A reasonable range of mahinga kai species were present.
    • This is not a traditional site and therefore scores 1 for the traditional species indicator in the mahinga kai component.
    • It scores 5 because iwi members would return to the site in the future.
  • It received an above average score for stream health:

Site 4: Unnamed tributary – Totora Hills stream (B–0 / 1.42 / 2.3)

The assessment confirmed that:

  • This is not a traditional site.
  • Because of the unhealthy condition of the site, iwi members would not return to the site.
  • Its mahinga kai values are below average.
    • It scores average for access. It was relatively easy for iwi members to access this site without assistance.
    • A limited range of mahinga kai species were present.
    • This is not a traditional site and therefore scores 1 for the traditional species indicator in the mahinga kai component.
    • It scores 1 because iwi members would not return to the site in the future.
  • It received a below average score for stream health:
    • Flow visible – 2.4
    • Water quality – 2.2

Site 5: Mangaoho Stream (B–1 / 2.62 / 4.0)

The assessment confirmed that:

  • This is not a traditional site.
  • Because of the healthy condition of the site, iwi members would return to the site.
  • Its mahinga kai values are average.
    • It receives an average score for access.
    • A reasonable range of mahinga kai species were present.
    • This is not a traditional site and therefore scores 1 for the traditional species indicator in the mahinga kai component.
    • It scores above average because iwi members would return to the site in the future.
  • It received a high score for stream health:
    • Flow – 4.1
    • Water quality – 3.9

Storing and accessing data

The data collected is for tangata whenua to manage. Applying the CHI creates a large amount of valuable information. It is important to think about how the data might be used and how to manage the information that has been collected. The data may be used to identify issues associated with a specific site and can be used to set priorities. If appropriate, the issues and priorities for management can be discussed with councils.

Note that the Takiwā software programme can be used to store the data you collect and to prepare reports. The software is available on the Ngāi Tahu website, www.ngaitahu.iwi.nz (type ‘Takiwā’ in the search box).

Team members producing stream health data at a site.