Consulting Hydrometry

Get specialist advice, support and training from Hydro-Logic Services consultants on hydrometric design and review, flow derivation and uncertainty, fish pass, hydraulic design and MCERTS.

Our Hydro-Logic Services Consulting Hydrometry team provides specialist guidance, advisory support and training across a full range of hydrometric services to help you monitor, understand and act on critical water management issues - enabling you to meet regulations, develop plans and react effectively to current and future water conditions.

Our capabilities

Hydrometric Design and Review

Hydrometric monitoring networks comprise a number of sites where water level and flow, rainfall/precipitation, hydro-meteorological, groundwater and water quality are measured, often using data loggers. The appropriate design and operation of hydrometric networks and monitoring sites is critical to the delivery of meaningful, actionable hydrological data. 

We provide specialist independent advice on the following elements of hydrometric design and review:

  • Network design and review
  • Site location and preliminary reconnaissance
  • Site survey and identification of environmental issues - e.g. fisheries, ecology
  • Outline design, planning and consents
  • Hydraulic and hydrological assessment, analysis and modelling
  • Detailed hydrometric design and specification
  • Equipment procurement, installation and commissioning
  • Performance checking, calibration and verification
  • Independent compliance and audit assessments
  • Fish passage improvements

We offer a complete service and regularly partner with specialists from related disciplines such as instrument manufacturers and suppliers, civil engineers, construction contractors and environmental scientists.

Flow Derivation and Uncertainty

Stage-discharge and velocity indexing techniques are of critical importance for obtaining accurate flow measurement. Stage-discharge relationships enable the conversion of observed water level measurements to flows where there is a consistent control feature such as a weir or stable river channel; velocity index techniques are used where no direct relationship exists between stage and flow. Velocity index techniques are required at sites where acoustic velocity meters or radar instruments are installed.

We have designed, operated and audited a wide range of flow monitoring sites, and in so doing have developed and reviewed numerous stage-discharge relationships and velocity index ratings for open channels, informal controls and formal structures. We are able to complement these techniques with rating extension throughout the full flow range using hydraulic analyses and 1D / 2D modelling techniques.

Uncertainty analysis is a means of gaining a better understanding of the quality of hydrometric data and the potential consequences for reliable decision making. We undertake uncertainty analysis for a wide range of flow measurement techniques.

Fish Pass and Hydraulic Design

Most UK rivers and streams have water level and flow control structures, and a significant number are used for flow measurement purposes. Many of these structures will require modification or even removal to improve fish migration in order to comply with EU regulations, particularly the Water Framework Directive and Habitats Directive.  

Our consultants are recognised specialists in the hydraulic analysis and design associated with the improvement of fish passage at hydrometric flow measuring structures, and we have undertaken hydraulic analysis in relation to a range of other water level and flow control structures, hydropower installations and flood defences. We provide specialist advice on effective, economical solutions, including full fish pass design and uncertainty analysis.


We are accredited by the UK Environment Agency to assess consent holders' environmental measurement arrangements under the Monitoring CERTification Scheme (MCERTS).


As framework training providers for the UK Environment Agency National Hydrometric Training programme since 1995 we are the leading providers of hydrometric training in the UK, and have experience of delivering training across the world. Our tutors have many years of practical experience in the fields of hydrometry and environmental data management, as well as extensive training experience.

As framework training providers for the UK Environment Agency National Hydrometric Training programme since 1995, we have developed and delivered over 160 courses to around 1900 delegates. We have also delivered courses to the Scottish Environmental Protection Agency (SEPA), the Environmental Protection Agency (EPA, Republic of Ireland), Office of Public Works (Ireland), Centre for Ecology and Hydrology (CEH), Affinity Water, Wessex Water and the Game and Wildlife Trust.

We currently offer the following courses:

  • Spot Flow Gauging
  • Introduction to Field Hydrometry
  • Advanced Hydrometry
  • Maths and Statistics for Hydrologists
  • Weirs and Flumes
  • Stage-Discharge and rating development: theory and practice
  • Velocity-Index rating development: theory and practice
  • Acoustic Doppler Current Profiler (ADCP) Gauging

Our courses typically comprise a mixture of classroom and field-based learning, together with workbooks and assessments. We are able to offer our own training facilities and field locations or deliver the courses in a place of our clients' choice. We can tailor course duration and material according to specific requirements and budget.