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Service 10

River Health Index
Composite basin assessment.

Composite river health assessment combining hydrological, physico-chemical, and biological indicators — producing a scored, GIS-mapped River Health Index for river basin management, government planning, and environmental compliance.

River Health IndexComposite indicatorsHEC-HMSCMIP6 scenariosGIS priority mapping21–35 days
At a glance
21–35 days
Standard delivery
3-scenario
Analysis approach
Composite
Index method
Every study includes
  • Composite Index — hydrological 40%, chemical 35%, biological 25%
  • Hydrological modelling with HEC-HMS & gridded rainfall
  • 3-scenario analysis — baseline, climate change, land use change
  • GIS priority zone mapping for intervention planning
  • Named engineer · Post-delivery support
HEC-HMS
Hydrological modelling
3 scenarios
Analysis depth
GIS mapping
Priority zones
21–35 days
Delivery
What it is

River Health Index — what HYDRisk delivers.

A River Health Index (RHI) provides a structured, quantitative assessment of the ecological and hydrological condition of a river basin — translating complex, multi-dimensional indicators into a single scored index that can be tracked over time, mapped spatially, and used to prioritise intervention.

The HYDRisk RHI methodology integrates three categories of indicator: hydrological indicators (flow regime, peak discharge, hydrological alteration — weighted at 40%), physico-chemical indicators (water quality, sediment, temperature — weighted at 35%), and biological indicators (aquatic biodiversity, riparian vegetation — weighted at 25%).

Three scenarios are analysed: baseline current conditions, climate change (SSP2-4.5 and SSP5-8.5 using CMIP6), and land use change — providing a forward-looking picture of how river health is projected to change and where intervention is most urgently needed.

HYDRisk River Health Index assessments are designed for government bodies, river basin management authorities, environmental agencies, and NGOs responsible for river basin management and reporting.

Why a River Health Index matters
“You cannot manage what you cannot measure. A composite RHI gives river basin managers a single, trackable metric.”
Three weighted indicator categories
Baseline, climate, and land use scenarios
GIS priority mapping for intervention
Built for government & basin authorities
Why it matters

Four reasons this service is critical to your project.

Understanding what this study delivers — and what happens without it — is the fastest way to evaluate whether your project needs it.

Basin management requires quantitative health metrics
Authorities need objective, quantifiable metrics to inform investment decisions and monitor restoration progress. A composite RHI provides exactly this.
Climate change will alter river health — plans must adapt
Changing rainfall, drought frequency and extreme events will alter flow regimes and ecology. An RHI incorporating CMIP6 lets management plans calibrate to future conditions.
Land use change is a primary driver of river degradation
Urbanisation, farming and deforestation alter runoff, sedimentation, water quality and flow regime. Quantifying it lets authorities target interventions where they matter most.
Multi-indicator scoring avoids single-metric blind spots
Relying on one indicator — water quality alone, for example — misses ecological and hydrological signals. A weighted composite gives a balanced, defensible picture.
What we deliver

Specific deliverables — not vague promises.

Every HYDRisk study produces a defined set of technical outputs — here is exactly what you receive.

Technical analysis outputs
  • Hydrological modelling — HEC-HMS with regional gridded rainfall
  • Discharge data integration and model calibration
  • Three-scenario analysis — baseline, CMIP6 climate change, land use change
  • Hydrological indicator scoring — flow regime, peak discharge, alteration
  • Physico-chemical indicator assessment — quality, sediment, temperature
  • Biological indicator assessment — biodiversity, riparian vegetation
GIS mapping & report deliverables
  • Composite RHI — scored by sub-basin, mapped in GIS
  • RHI change maps — baseline vs. climate vs. land use scenarios
  • Priority zone map — intervention prioritisation based on scores
  • Hydrological modelling results — flow regime per sub-basin
  • RHI report — methodology, scoring, results, recommendations
  • GIS spatial data — all indicators & composite index in Shapefile/GeoTIFF
Deliverable formats: PDF report. GIS spatial data in Shapefile and GeoTIFF. Excel summary tables. QGIS project file with all layers for client GIS use.
Request a scope →
Tools & methodology

Industry-standard tools. Region-specific data.

Every tool we use is the same software trusted by government agencies, major engineering firms and regulatory bodies worldwide.

HEC-HMS
US Army Corps of Engineers
Hydrological modelling for flow regime analysis — the primary hydrological indicator component of the RHI.
Flow regimeCalibration
CMIP6 / ERA5
World Climate Research Programme
CMIP6 SSP2-4.5 and SSP5-8.5 scenarios for future river health projection. ERA5 for historical baseline.
Climate scenariosFuture projection
QGIS / ArcGIS
Open Source / Esri
Spatial analysis for composite index mapping, priority zone identification, and sub-basin visualisation.
Index mappingPriority zones

Step-by-step methodology

Step 01
Watershed & sub-basin delineation
DEM-based watershed delineation. Sub-basin boundaries defined. Stream network mapped. Gauge station locations identified.
Step 02
Data collection
Gridded rainfall, discharge records, water quality data, land use maps, biological survey data where available.
Step 03
Hydrological modelling
HEC-HMS model built and calibrated. Baseline flow regime simulated. Climate and land use change scenarios run.
Step 04
Indicator scoring
Hydrological indicators scored from model outputs. Physico-chemical and biological indicators scored from field data.
Step 05
Composite RHI calculation
Weighted composite score calculated per sub-basin. Composite RHI mapped in GIS. Change analysis across scenarios.
Step 06
Priority mapping & report
GIS priority zone map produced. RHI report written. Intervention recommendations based on scenario analysis.
Regional applicability

Calibrated for your region and regulatory framework.

Methodology, data sources and regulatory requirements differ between geographies. HYDRisk delivers the right approach for every region.

United States — Primary market
USGS-based methodology
USGS discharge and water quality data, NOAA rainfall, EPA river health frameworks.
Regulatory frameworks
EPA Clean Water ActUSGS standards
  • USGS discharge & water quality data integration
  • State & federal river basin planning support
  • EPA Clean Water Act reporting alignment
Middle East & GCC
GCC-specific methodology
Wadi flow regime characterisation, arid-region water quality benchmarks.
Regulatory frameworks
UAE MunicipalityRegional water authorities
  • Wadi and ephemeral flow regime characterisation
  • Regional water authority engagement
  • Arid-region ecological indicator benchmarks
International
Global RHI methodology
CMIP6 projections, ERA5 baseline, adaptable indicator weighting for any basin.
Regulatory frameworks
EU Water FrameworkWorld Bank basin frameworks
  • CMIP6-aligned climate scenario integration
  • World Bank & development bank reporting formats
  • Remote delivery — any river basin covered
Related services

Services often commissioned alongside this study.

Service 07
Watershed Analysis
Watershed analysis defines the study boundary and sub-basin structure integral to any River Health Index study.
View service →
Service 04
Hydrological Studies
The hydrological modelling component of the RHI — flow regime, peak discharge and hydrological alteration indicators.
View service →
Service 06
Climate Flood Risk
CMIP6 climate scenario analysis applied to future river health projection under changing rainfall and temperature conditions.
View service →

Ready to commission a River Health Index assessment?

Tell us your river basin, available data, and reporting requirements. We will scope the RHI study and have a fixed-fee proposal within 24 hours.

Get a free consultation →
Proposal within 24hFixed-fee pricingNo obligation