Water Resources & Hydraulic Engineering

Highly specialised requests are first checked for feasibility from this information. Please do not send confidential data through the public form; describe it first and agree secure transfer afterwards.

1. 01Enquiry and requirement assessment
2. 02Technical scoping and proposal
3. 03Execution
4. 04Quality review and delivery, with an agreed round of revisions

Read the full project workflow.

In depth: how the work is done

1. Open-channel and pipe-network hydraulics

   Open-channel flow is described by energy and momentum principles with friction, commonly through Manning-type relations; gradually varied flow, hydraulic jumps and critical flow regimes produce distinct behaviour. Pressurised systems are analysed with head-loss formulas and network solutions, with transient effects such as water hammer when flow changes rapidly. We select the level of modelling suited to the question and check results against simple hand calculations and known cases.

2. One- and two-dimensional hydraulic modelling

   One-dimensional models represent flow along a channel with cross-sections and are efficient for river reaches and drainage networks. Two-dimensional models resolve flow over floodplains, around structures and in wide channels, at greater computational cost and data demand. Terrain data resolution, roughness assignment, boundary conditions and numerical stability drive accuracy. Calibration compares modelled and observed levels or extents, and parameters are adjusted within physically sensible ranges.

3. Frequency analysis and extreme-value statistics

   Design flows and rainfall depths are estimated from records using extreme-value distributions, such as the generalised extreme value, Gumbel and log-Pearson families, fitted by methods that account for sample size. Estimates for long return periods rely on extrapolation and carry wide confidence intervals, which should be reported. Non-stationarity from climate or land-use change challenges the assumptions of standard methods and is discussed explicitly.

4. Rainfall-runoff concepts

   Rainfall-runoff models range from simple unit-hydrograph and rational-method approaches to conceptual and distributed models. They convert rainfall to runoff through losses, routing and storage. Parameters are calibrated using observed events, and the calibration period must be separate from the validation period. Uncertainty arises from rainfall input, parameter equifinality, where different parameter sets fit equally well, and model structure.

5. Water-supply and reservoir system analysis

   Reservoir and supply system studies assess reliability, such as the probability of meeting demand, using simulation or optimisation with inflow sequences. Stochastic inflow generation, drought analysis and demand scenarios inform planning. Trade-offs between objectives, such as supply security, flood control and environmental flows, can be explored with multi-objective methods, with decisions left to the responsible authorities.

6. Communicating uncertainty to decision makers

   Hydraulic and hydrological results are frequently used by people who are not modellers, so the way uncertainty is shown matters. We suggest presenting results as ranges linked to the main uncertain inputs, such as roughness, boundary flows and record length, instead of a single depth or flow. Maps and long-section plots can show envelopes rather than lines. A short statement should explain what the model cannot represent, for example blockages, ungauged tributaries or future land-use change, so that the limits of the study are visible beside the numbers and are not hidden in an appendix.

Common pitfalls this service helps avoid

• Extrapolating frequency curves too far. Estimates for return periods much longer than the record are highly uncertain.
• Calibrating and validating on the same events. This overstates model predictive ability.
• Neglecting roughness uncertainty. Roughness values strongly influence water levels and are often poorly known.
• Using coarse terrain data. Inadequate topographic resolution can misrepresent flow paths and flood extents.

What good reporting looks like

A hydraulic or water-resource report describes the system and data with their quality, the model type and set-up, boundary conditions, calibration and validation with performance measures, the statistical analysis with confidence intervals, scenario results, sensitivity to uncertain inputs and limitations. It does not constitute a flood-risk assessment for regulatory or design purposes, which must be carried out by qualified professionals according to applicable standards.

An illustrative scenario

Hypothetical example written for explanation. It is not a client case, a result or a testimonial.

Suppose a researcher examines flood levels in a small urban channel. Annual maximum flows from a gauge are fitted with extreme-value distributions, and the confidence interval for the hundred-year flow is wide. A hydraulic model calibrated to a recent flood reproduces observed levels within tolerance after adjusting roughness. The report presents water levels for a range of flows and roughness and states that culvert blockage was not considered.

Questions to settle before you begin

• How long and reliable is my flow or rainfall record?
• What data will I use to calibrate and validate the model?
• How uncertain are roughness and boundary conditions?
• Is the climate or land use stationary over the planning period?
• What decisions will rely on the results?

Key terms

Return period

The average interval between events of a given magnitude.

Manning's roughness

A coefficient representing channel resistance to flow.

Hydrograph

A graph of discharge over time.

Equifinality

The existence of many parameter sets giving similarly good fits.

Generalised extreme value distribution

A family of distributions for block maxima.

Working together on Civil, Structural & Infrastructure Engineering projects

Civil, structural and infrastructure research engagements start with a description of the structure or system, the loads and environment, the codes or standards that provide context and the questions the research must answer. We ask for drawings or descriptions, material data, monitoring data where they exist and any previous analyses. The work provides research analysis, literature-based assessment and documentation. It does not replace the design responsibility of licensed engineers, code compliance checks or site-specific professional judgement, and it states clearly where those are required.

Few projects need a single service in isolation. These are the services most often combined with this one.

• Hydrology & Hydrogeology

  Modelling and data analysis for surface-water and groundwater systems, including water balance, rainfall-runoff and groundwater-flow concepts.

• Fluid Flow Analysis

  Analysis of single-phase flow in pipes, channels, turbomachinery and around bodies, combining analytical estimates, empirical correlations and numerical simulation as appropriate.

• Climate & Environmental Modelling

  Analysis and modelling of climate and environmental data and processes, including statistical downscaling concepts, trend analysis and environmental transport modelling.

• Environmental Engineering

  Research support for water, wastewater, air and solid-waste engineering, including treatment-process modelling, monitoring-data analysis and environmental-impact assessment concepts.