A small hydrodynamics practice on the dock that the Severn built

The principal

Dr. Gareth Bowen is a chartered civil and marine engineer, a Member of the Institution of Civil Engineers and the practice's principal hydrodynamicist. He trained in civil engineering at Cardiff, took a doctorate in estuarine sediment dynamics with field work on the Severn and the Loughor, and spent eight years with a large coastal consultancy on barrage, lagoon and port studies in the Bristol Channel, the Mersey and the Solway before founding the practice in 2015. He has given evidence at two development consent examinations, sits on an industry working group for tidal-range turbine standards, and still takes the gauge boat out himself when the survey contractor is busy.

His research interests are narrow and he is candid about it: cavitation in reverse-running low-head bulb runners, the shallow-water overtides that skew the Severn curve, and the fate of fine sediment once an impoundment changes the residual current. The research notes on the home sheet are his, revised as the data comes in.

The practice

Trading name

Severn Tidal Hydro-Engineering

Legal entity

Severn Estuarine Marine Energy Research Ltd., a private company limited by shares, registered in England and Wales

Registered office

18 Mount Stuart Square, Cardiff Bay, Cardiff CF10 5DP, United Kingdom

Founded

2015

Principal

Dr. Gareth Bowen, CEng, MICE, Principal Hydrodynamicist

Practice email

hydro@severntidal.com

Principal's email

bowen@severntidal.com

Insurance

Professional indemnity and public liability held with a UK insurer; certificates available to clients on request

Mount Stuart Square was built in the 1880s as the business square of the Cardiff coal trade. The Coal Exchange is across the road. We like being here because the square was laid out by engineers who understood that the Severn's tide was the reason the docks existed at all. The tide is still the reason we exist. Everything else is detail.

How we work

We take on a small number of studies at once and we stay with them. A typical feasibility engagement runs like this.

1. Basin and data review. We check the proposed outline against the bathymetry, identify which tide gauges and current records can be trusted, and tell you which cannot.
2. Zero-dimensional yield model. The same physics as the calculator on the home sheet, run across a full 18.6 year nodal cycle with a real turbine hill chart. This stage gives the first honest energy number and usually resets expectations in one direction or the other.
3. Two-dimensional hydrodynamic model. A depth-averaged model of the estuary with and without the scheme, calibrated against measured constituents, to find the real head at the turbines and the change in currents outside the wall.
4. Turbine cavitation and draft-tube check. The proposed runner and setting are tested against the full head range of the schedule, in both directions if dual-mode.
5. Sediment and morphology. Coupled sediment runs to show where the silt goes, over years rather than tides.
6. Report. Written to be read by an investor, a planning inspector and a sceptical engineer, in that order of priority and the reverse order of detail.

We say no to work we are not suited to. We do not do wave energy, offshore wind foundations or anything requiring a vessel bigger than our own. We will tell you who does.

Contact

Write to hydro@severntidal.com for the practice, or to bowen@severntidal.com if you would rather start with the principal. A basin outline, a tide gauge you trust and a plain statement of the question you need answered are the three things that make a first conversation useful. The office is open from nine until half past five, Monday to Friday, and visitors are welcome by arrangement. The feasibility desk is on the home sheet.