IIMA Compliance & Allocations

The Incomati and Maputo Agreement (IIMA) dictates specific restrictions on water abstractions and minimum environmental flow rates (Eflows) at international borders. This module tracks and logs compliance with these requirements.

Data Models Reference

 ┌──────────────────────┐        ┌──────────────────────┐
 │ iima_user_categories │◄───────│  iima_allocations    │ (Allocated shares
 └──────────▲───────────┘        └──────────────────────┘  per country & cat)
            │
            │                    ┌──────────────────────┐
            └────────────────────│  water_abstractions  │ (Actual volumes
                                 └──────────────────────┘  abstracted)
                                            │
                                            ▼
                                 ┌──────────────────────┐
                                 │iima_compliance_record│ (Calculates
                                 └──────────────────────┘  compliance %)

1. iima_user_categories

Defines priority categories for water users. It includes:

• assurance_pct_primary / allocation_share_primary: Priorities for domestic, municipal, and ecological uses.
• assurance_pct_secondary / allocation_share_secondary: Secondary priorities (industrial and agriculture).

2. iima_eflow_requirements

Maintains the minimum environmental flow rate (m³/s) for critical cross-border locations:

• Key Monitoring Point: Sabie River, Crocodile River, Incomati Main Stem.
• Tied Station: Links to a specific physical telemetry station (station_id).

3. iima_allocations

Defines the volume of water (million m³/annum) allocated to Eswatini, Mozambique, and South Africa for each user category in a given subcatchment.

4. water_abstractions

Records the actual volume of water abstracted by each country in a given period.

Compliance Calculation Workflow

The system calculates compliance metrics on a recurring basis or when triggered by data uploads.

1. Eflow Compliance

• The system compares the average flow rate (m³/s) at a border monitoring station over the evaluation period against the min_flow_m3_s defined in iima_eflow_requirements.
• If the actual flow is equal to or greater than the threshold, compliance is marked true (100%).
• If the actual flow drops below the threshold, compliance is marked false, and an alert is flagged on the manager’s dashboard.

2. Abstraction Compliance

• The system sums all abstractions logged in the water_abstractions table for a specific country, subcatchment, and user category.
• It compares this total against the corresponding iima_allocations limit.
• Compliance Percentage:

  Compliance % = (Actual Abstraction / Allocated Volume) * 100

• If the abstraction exceeds 100%, it violates the IIMA agreement and triggers restriction actions.

Restriction Level Triggers

When water availability in the basin drops to critical levels (e.g. during severe droughts), the IIMA mandates progressive curtailments on secondary uses:

• Restriction Level 1: Voluntary reduction guidelines for agricultural abstractions.
• Restriction Level 2: Mandatory $10%$ curtailment on agricultural and industrial licenses.
• Restriction Level 3: $20%$ curtailment on agriculture; suspension of non-essential industrial abstractions.
• Restriction Level 4 (Critical): All water resources are redirected to primary domestic consumption and ecological flows. Abstraction for other categories is suspended.