Environmental Expert Witness & Water Pollution Legal Advisory
Independent environmental expertise for complex pollution, water-quality and environmental harm matters.
Specialist technical environmental advisory and expert witness services drawing on more than 12 years of direct experience supporting legal, regulatory, water-company, energy and environmental projects, combined with more than 30 years of professional experience in marine, freshwater and environmental science.
A specialist technical service for environmental and water-related legal matters
Environmental cases involving pollution can depend on the quality of the underlying technical evidence. My particular area of expertise is the assessment of environmental harm arising from pollution affecting freshwater, transitional and marine environments, including pollution associated with water-company infrastructure, wastewater systems, industrial activities, energy operations and accidental releases.
Questions I can help answer
- What happened? What was released? Where did it come from?
- What pathway did the pollutant take?
- What was the likely or demonstrated environmental impact?
- How extensive was the affected area? How persistent was the impact?
- What receptors were affected — water quality, ecology, fisheries, amenity?
- What evidence supports the assessment?
- What mitigation was available?
- What does the scientific evidence actually demonstrate?
Expert witness and legal technical support
Initial technical review
A preliminary review to establish what technical evidence exists, what is missing, whether available environmental data are sufficient, and whether proposed environmental conclusions are scientifically supportable.
Technical advisory support
Specialist environmental advice to legal teams and clients dealing with water pollution incidents, wastewater discharges, sewage and sewer-network pollution, industrial discharges, oil and hydrocarbon spills, plastics and microplastic pollution, and ecological impacts.
Expert reports
Where formally instructed, technical expert reports, environmental impact assessments, pollution-impact assessments, evidence reviews, interpretation of environmental monitoring data, technical opinions, and independent review of other expert evidence.
Witness statements & litigation support
Technical input into witness statements, position statements, skeleton arguments, chronologies of environmental events, technical evidence schedules, preparation for conferences with counsel, expert meetings, and cross-examination.
Water pollution and environmental harm assessment
A core area of experience is assessing the environmental consequences of pollution incidents and providing technical evidence relating to the severity, extent, persistence and ecological consequences of pollution. The Environment Agency uses the Common Incident Classification Scheme (CICS), with categories ranging from Category 1 (major, serious, persistent impact) through Category 4 (substantiated incident with no impact).
Water quality
- Physical and chemical water-quality impacts
- Contaminant characteristics and pathways
- Dissolved and particulate contaminants
- Persistence, dilution and receiving-water characteristics
- Surface water and groundwater interactions
Ecological receptors
- Fish, aquatic invertebrates and macrophytes
- Plankton and protected species
- Habitats, fisheries and wider ecological communities
Environmental extent & persistence
- Spatial extent and duration of pollution
- Acute versus longer-term effects
- Recovery potential and secondary environmental effects
Experience supporting environmental prosecutions
Experience supporting matters involving the Environment Agency and environmental prosecution proceedings, including technical witness support, project management, client liaison and environmental evidence.
Southern Water
2025Legal Advisory
Confidential technical legal witness support. Provided specialist environmental technical support in connection with legal proceedings, drawing on experience in pollution, water environments, environmental assessment and expert witness practice.
Pennon Group / South West Water
2022Technical witness support
Technical support, project management and client liaison associated with an Environment Agency prosecution matter.
Linklaters LLP
2021Technical witness support
Provided technical environmental support, project management and client liaison in connection with legal work involving Southern Water and an Environment Agency prosecution.
Anglian Water / Environment Agency
2024Senior Sustainability Plastics Advisor
River Positive Plastic Capture Project — investigating plastic pollution and developing an evidence base around plastic types, polymer types, size ranges, fibres, microplastics, pollutant indicators, wastewater pathways and catchment-scale pollution pathways.
These examples are presented at a high level because the underlying matters may be confidential. They demonstrate the nature and level of work undertaken without disclosing privileged, confidential or commercially sensitive information.
My approach
Establish the question
What specific environmental issue needs to be answered?
Review the evidence
Examine the available technical, scientific and documentary evidence.
Establish source and pathway
Where possible, identify the source, pathway and environmental receptors involved.
Assess environmental impact
Consider the nature, extent, persistence and significance of the environmental effects.
Identify uncertainty
Clearly distinguish established evidence from assumptions, limitations and areas where further evidence is required.
Provide an independent technical opinion
Reach conclusions that are supported by the available evidence and fall within my professional expertise.
Consider mitigation
Where appropriate, identify realistic measures that could prevent, reduce, control or compensate for environmental harm.
Who I can support
Water and wastewater companies
Technical environmental review, pollution assessment, mitigation and independent technical advice.
Energy and power companies
Environmental impact assessment, pollution incidents, marine and freshwater impacts and mitigation.
Legal firms
Technical environmental support for solicitors and counsel instructed in environmental, regulatory and pollution-related matters.
Environmental regulators
Independent technical analysis, evidence review and environmental assessment where appropriate.
Insurers and risk professionals
Technical assessment of environmental incidents, impacts, evidence and mitigation options.
Organisations responding to incidents
Independent scientific review of the environmental consequences and potential mitigation response.
Discuss a potential instruction
If you are a solicitor, barrister, water company, energy company, insurer or other organisation seeking specialist environmental technical support, I can provide an initial discussion to establish whether the matter falls within my experience and professional competence.
Water pollution · Wastewater · Environmental harm · Water quality · Pollution incidents · Ecological impact · Oil spills · Energy-sector pollution · Plastics and microplastics · Environmental mitigation · Regulatory proceedings · Prosecution support · Expert witness evidence
Contact Rowan ByrneInitial enquiries are subject to conflicts, scope, availability and confirmation that the proposed instruction falls within my professional expertise.
Frequently asked questions
Common questions from solicitors, barristers, and organisations seeking environmental expert witness support.
Who is Rowan Byrne?
Rowan Byrne CSci FRSB is an Irish marine biologist, marine ecologist, Chartered Scientist, and Fellow of the Royal Society of Biology with over 30 years of professional experience in marine and environmental science. He is a TEDx speaker, RTÉ Radio 1 and Newstalk Breakfast commentator, and an environmental expert witness providing specialist technical support for water pollution, wastewater, and ecological harm matters in Ireland and the UK.
Who is a qualified marine biology expert witness in Ireland and the UK?
Rowan Byrne CSci FRSB is a qualified marine biology and environmental expert witness based in Ireland, providing specialist services across Ireland and the United Kingdom. He is Bond Solon expert witness trained, operates in accordance with CPR Part 35, and has over 12 years of experience supporting environmental legal and regulatory proceedings — including matters involving the Environment Agency, Southern Water, Pennon Group/South West Water, and Linklaters LLP.
What types of water pollution cases does Rowan Byrne cover?
Rowan Byrne provides expert witness and technical advisory services for cases involving wastewater and sewage discharges, water company infrastructure failures, industrial and energy-sector pollution, oil and hydrocarbon spills, plastics and microplastic pollution, ecological harm to rivers, estuaries and marine environments, and Environment Agency prosecution matters.
What qualifications does Rowan Byrne hold as an expert witness?
Rowan Byrne holds Chartered Scientist (CSci) status from the Science Council, is a Fellow of the Royal Society of Biology (FRSB), has completed Bond Solon expert witness training, and operates in accordance with CPR Part 35. He has 30+ years of professional experience in marine and environmental science and 12+ years supporting legal, regulatory, and prosecution proceedings.
Can Rowan Byrne act as an expert witness for environmental cases in Ireland?
Yes. Rowan Byrne provides environmental expert witness services in both Ireland and the United Kingdom. He is based in Ireland and has extensive experience of Irish marine, freshwater, and coastal environments, as well as familiarity with Irish environmental regulatory frameworks including the Environmental Protection Agency (EPA Ireland) and relevant planning and marine consent processes.
How do I instruct Rowan Byrne as an environmental expert witness?
Solicitors, barristers, water companies, energy companies, insurers, and other organisations can contact Rowan Byrne via the contact page on marinecreatures.com to discuss a potential instruction. Initial enquiries are subject to conflicts checks, scope confirmation, and availability.
Important information about expert evidence
This service provides specialist environmental and technical expertise. It does not constitute legal advice. Where formally instructed as an expert witness, my overriding duty is to assist the court on matters within my expertise. My opinions will be independent and evidence-led. The service does not guarantee a particular regulatory, enforcement or court outcome.