ABMAP Reference Sites

Reference sites for the ABMAP programme were evaluated by considering specific reference selection criteria that conceptually relate to impact sources or drivers. Selection criteria used to determine eligibility for reference site consideration are given below. Each criterion is given a score according to perceived impacts (1 – very major impact, 2 – major impact, 3 – moderate impact, 4 – minor impact, 5 – indiscernible impact). A site is considered to be in reference condition where it does not score less than ‘4’ for any criterion.

Reference Condition Selection Criteria

1. Influence of intensive agriculture upstream *

   Intensive agriculture is that which involves irrigation, widespread soil disturbance, use of agrochemicals and pine plantations. Dry-land grazing does not fall into this category.

2. Influence of major extractive industry (current or historical) upstream *

   This includes mines, quarries and sand/gravel extraction.

3. Influence of major urban area upstream

   This will be relative to population size, river size and distance between the site and the impact.

4. Influence of significant point-source waste water discharge upstream *

   Exceptions can be made for small discharges into large rivers.

5. Influence of dam or major weir *

   Sites within the ponded area of impoundments also fail.

6. Influence of alteration to seasonal flow regime

   This may be due to abstraction or regulation further upstream than the coverage by Criterion 5. Includes either an increase or decrease in seasonal flow.

7. Influence of alteration to riparian zone

   Riparian vegetation should be intact and dominated by native species.

8. Influence of erosion and damage by stock on riparian zone and banks

   Stock damage to the stream bed may be included in this category.

9. Influence of major geomorphological change on stream channel

   Geomorphological change includes bank slumping, shallowing, braiding and unnatural aggradation or degradation.

10. Influence of alteration to instream conditions and habitats

    This may be due to excessive algal and macrophyte growth, by sedimentation and siltation, by reduction in habitat diversity by drowning or drying out of habitats (e.g. riffles) or by direct access of stock into the river.

* Note: the level of impact at a site will generally decrease as the distance from the source of impact increases.

Last updated: 22 March 2013