Richard Allitt Associates

As consulting engineers, RAA works with clients across a wide variety of sectors, including local authorities, that require high-quality urban drainage, specialising in assessments, forecasting, surface water management and drainage.

Flood risk services include detailed risk assessments, such as mitigation measures, urban flood forecasting incorporating both real-time and short-term forecasts, strategic flood risk assessments, breach analysis, surface water management plans and hydraulic modelling. Alongside this, the company also operates a division called Remote Aerial Surveys (RAS), which offers high-quality mapping and aerial surveying services to aid with flood risk management.

RAA’s hydraulic modelling experts provide highly specialised hydraulic models, building and evaluating very detailed scenarios to deal with complex drainage problems. Using state-of-the-art analytical techniques to actively develop and improve technical ideas while striving to maintain the same quality of performance and output, the business uses InfoWorks™ integrated all source catchment modelling (ICM) because of its superior power and detailed 1D–2D coupling capabilities. Services can include drainage area plans and sewerage management plans, surface water management plans, 1D–1D/2D modelling, breach analysis, river modelling, research and development, technical audits and remote simulations.

Expert witness services are offered to provide constructive, practical advice on all matters within the urban drainage, flooding and hydraulic engineering industries for legal disputes, court cases and public inquiries.

Hydrology services include assessment of fluvial flood event flows, use of observed data and its analysis, drainage analysis, climate change impacts testing, sizing of storage reservoirs, drainage and rainfall run-off and review and quality assurance of existing studies.

RAA is also a partner of Susdrain, advocating for sustainable drainage schemes (SuDS) and supporting their implementation. This includes computer modelling of the hydraulic behaviour of sewer networks, SuDS, watercourses and flooding in the urban environment.

Remote simulation (Rsim) services are offered to assist clients with running integrated model simulations, as well as performing technical checks, auditing and training where required.

Clients include Scottish Water, Anglian Water, Wessex Water, Severn Trent Water, Southern Water, the UK Department for Environment, Food and Rural Affairs (Defra) and Network Rail.