Data Acquisition Plan
Five survey programmes · Terms of Reference · Critical path to DFI approval
All five survey programmes are on the critical path to AfDB board approval in Q4 2028. The hydrological study and ESIA are the longest-lead items (18 months each). ToRs must be issued this quarter to maintain the programme timeline.
Scope of Work
- →Establish 4 stream gauging stations in Sheikh highlands catchment
- →Two full rain seasons data (minimum) for MAR validation
- →Flood frequency analysis (Q50, Q100, Q500) for dam design
- →Groundwater baseline in Berbera coastal aquifer
- →Sediment transport study for dam sedimentation rate
Why this is critical
The dam MAR (Mean Annual Runoff) of 62.4 Mm³/yr is currently modelled from GIS. Physical gauging data is required to validate or revise the dam size and the water balance. AfDB will not approve the water component without at least 12 months of gauging data.
Scope of Work
- →5 cm GSD orthophoto of full 8,927 ha planning boundary
- →Digital Terrain Model (DTM) and Digital Surface Model (DSM)
- →Ground control points established using CORS network
- →Building footprint extraction and height measurement
- →Pipeline route corridor survey (320 km × 200m strip)
Why this is critical
All 15 notebooks use SRTM 30m DEM as a placeholder. The 5 cm UAV DTM replaces this in all engineering calculations — pipeline grading, dam catchment, flood modelling, and urban layout.
Scope of Work
- →220 soil survey points in Sheikh highlands (AEZ classification)
- →Soil salinity profile (ECe) to validate pykrige kriging model
- →Soil depth, texture, organic matter, pH measurements
- →Land degradation assessment
- →Irrigation suitability mapping (AEZ-A, AEZ-B, restricted, excluded)
Why this is critical
AEZ zone boundaries in NB13 are modelled from kriging interpolation. Physical soil surveys validate or revise these boundaries — the 80,000 ha figure and USD 637M/yr revenue projection depend on AEZ classification.
Scope of Work
- →Site characterisation: boreholes ×12 to 30m depth
- →Foundation material classification (USCS)
- →Seismic hazard assessment (peak ground acceleration)
- →Reservoir rim stability analysis
- →Construction material sources investigation
Why this is critical
ICOLD (International Commission on Large Dams) requires full geotechnical investigation for Class II dams. AfDB will not finance the dam without a completed geotechnical report.
Scope of Work
- →Scoping study and terms of reference (3 months)
- →Baseline environmental survey (marine, terrestrial, cultural)
- →Social survey: PAPs (Project-Affected Persons) census
- →ESMP (Environmental and Social Management Plan)
- →Public consultation (minimum 3 rounds, bilingual)
- →Resettlement Action Plan if required
Why this is critical
The ESIA is the longest-lead item — 18 months from scoping to final approval. World Bank ESF and AfDB ESAP standards both require a completed ESIA before board presentation. The clock starts with ToR issue.
Survey Programme Budget Summary
| ToR | Study | Budget | Duration | Critical path? | Lead agency |
|---|---|---|---|---|---|
| ToR A | Hydrological study | USD 850k | 18 months | Yes | MWR |
| ToR B | UAV topographic survey | USD 380k | 6 months | Yes | Municipal Planning |
| ToR C | Soils & agriculture | USD 620k | 8 months | No | Ministry of Agriculture |
| ToR D | Geotechnical (dam) | USD 1,200k | 9 months | Yes | MWR |
| ToR E | ESIA | USD 2,500k | 18 months | Yes | EPA + MoF |
| TOTAL | — | USD 5,550k | — | — | — |