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METSI CONSULTANTS: SUMMARY OF MAIN FINDINGS FOR PHASE 1 DEVELOPMENT
Table C.1 An example of the information contained in a consequence entry. Sev. = severity rating. % = equivalent
percent reduction or increase in abundance or occurrence. For an explanation of severity rating see
Section 4.2.
Site
Flow
Aspect
IFR 1 Wet-season
low flows
Reduction
Level
Compo
nent
Sub-component Result Sev. % Ecological Comment Social Comment
Level 3 Fish Maluti Minnow Decrease 4 60-80% It is expected that the reduction of the Not commonly
low flow wet period will have a major caught or utilised.
impact on habitat quality and quantity. Red data species
This change to the flow regime would
significantly alter the prediction for this
critically endangered species at this
site, as spawning and migration cues,
and availability and quality of spawning
and incubation habitat would be
reduced. Suitability (habitat criteria) of
lateral habitats for refuge, foraging and
passage of larvae and juveniles would
also be reduced. Consequences
would be evident in the form of
changes in the abundance of larvae
and juveniles and spawning success
and hatching would be compromised.
SOCIO-ECONOMIC COMPONENTS OF THE PROCESS
Identifying the Social Impacts of Biophysical River Changes
Step 17: The extent and nature of use of river resources by riparian people, and the present state of their health
and that of their domestic stock, were described and quantified. The Population At Risk (PAR) was
identified.
Step 18: The predicted reductions in availability of the resources and services under any potential flow regime
(Step 16) were used to rank the social impact for each resource and each health issue.
Calculating the Economic Assessment of Compensation and Mitigation
Step 19: An economic assessment was made of the current value of all river resources and services used by
the PAR, using information from the detailed social survey.
CALCULATING THE IMPACT ON THE SYSTEM YIELD
Step 20: A yield analysis was performed using the volumes calculated in Step 14, to determine the impact of
supplying a given flow regime to the downstream river on the yield.
OUTPUTS OF THE DRIFT PROCESS
The outputs consisted of the predicted consequences of four possible future flow regimes for the study rivers.
These were referred to as IFR scenarios, and consisted of the following information.
A modified flow regime for each part of each affected river. This is expressed in terms of:
− low flows: seasonal upper and lower discharge ranges, and monthly averages for discharge and
volume.
− high flows:magnitude, duration and timing of flood events.
Report No. 678-F-001 C-3