Location
Central London with flexible hybrid working model. Opportunities to work across multiple UK offices including Manchester, Leeds, Basingstoke, Birmingham, Bristol, Edinburgh, Dublin, Nottingham, Croydon, and Exeter.

Hours
Full Time - Flexible hybrid working arrangements available

Salary
Competitive salary commensurate with experience

About the Role
Join AECOM’s dynamic and multidisciplinary Water Environment team as a Principal Water Quality Modeller, a senior technical role leading innovative water quality projects across fluvial, estuarine, lake, and coastal environments. You will guide junior staff, collaborate with hydrologists, network modellers, and engineers, and act as technical lead on a diverse portfolio including catchment-wide chemical investigations, Environmental Improvement Programme (WINEP) delivery, natural flood management, river restoration, nutrient modelling, and storm overflow investigations. Your work will support water utilities, industrial clients, government agencies, and local authorities, helping shape the future of water quality management.
This role offers the opportunity to conceptualise and develop modelling approaches, build and validate water quality models, produce high-quality technical reports, lead tender submissions, mentor team members, and maintain strong client relationships. You will work closely with multidisciplinary teams to deliver projects aligned with environmental legislation and client requirements, driving innovation and efficiency in water quality assessments and modelling tools.

Experience
- Proven expertise in water quality science, including knowledge of compounds such as cryptosporidium, PFAS, geosmin, and disinfection by-products.
- Significant experience with fluvial and/or coastal water quality modelling software and Environment Agency requirements for UPM or WINEP studies.
- Skilled in model building and mass balance calculations, including flow-weighted and Monte Carlo statistical methods.
- Experience with hydrological assessment tools such as REFH2 and FEH.
- Familiarity with scripting languages (Python, Anaconda, R) and strong GIS skills (QGIS, ArcGIS, MapInfo) is advantageous.
- Demonstrated success in technical project delivery, including bid preparation, proposal drafting, project management, and report writing.

About you
Motivated and collaborative professional with strong leadership and mentoring capabilities. You are comfortable presenting complex technical information clearly to diverse audiences and thrive in a multidisciplinary team environment. You are proactive in keeping up-to-date with relevant legislation and technological developments and are committed to delivering high-quality, innovative solutions for clients.

Qualifications
- Master’s degree or equivalent in hydrology, engineering, mathematics, or a related discipline.
- Extensive technical knowledge and experience relevant to water quality modelling and environmental assessments.
- Strong communication skills, both written and verbal, with the ability to produce detailed technical documentation and engage effectively with clients and stakeholders.
- If you have transferable skills and meet some of the requirements, your application will be welcomed.