Surface Water & Groundwater Risk Assessments

Understanding the Complex Cycle of Water

Surface water in streams and rivers is an essential resource, as is the groundwater stored below ground in geological strata called aquifers. Ayesa conducts complex groundwater and surface water risk assessments to guide the design and management of many public and private projects and fulfil compliance and regulatory obligations.

Water Flow and its Ecosystem

When undertaking water-based risk assessments, we combine inputs from multiple experts (hydrogeologists, hydrologists, water and geotechnical engineers) analysing the flow and quality of water and its implications across the entire ecosystem.  Our expertise within this area is evidenced by our consulting services across significant wide-ranging schemes: our hydrological and surface water risk assessments guide the design of the flood relief schemes at Arklow and Bandon Ireland; the team’s groundwater monitoring (including baseline and post-remediation) of our land remediation solution at the Ineos Grangemouth Chemical Facility provided the regulatory approval and validation to help deliver the £50 million energy from waste facility.

Our surface water and ground risk assessment services guide and assist:

• Pre-construction
• Water and transportation infrastructure – delivering a sustainable, safe water supply (water supply, wastewater, drainage)
• Catchment modelling and management (Flood Relief Schemes, Flood Management Schemes, wetlands creation)
• Commercial and residential developments
• Hydrogeological and geological impacts for mineral extraction activities (including mine closure)
• Waste management facilities from planning, licensing to closure and post-closure
• Subsurface construction (transportation/rail, tunnelling, micro-tunnelling)
• Supporting planning applications for EfW (Energy from Waste Facilities), landfill and mineral extraction and quarry restoration
• Environmental permit applications for landfill and deposit for recovery sites
• Monitoring programmes and operational compliance for waste and other industries
• Applications for permits for groundwater abstraction
• Design of mitigation and land remediation schemes, including wetlands, a cost-efficient way to remove nitrogen with minimal human labour and energy

Groundwater Flow Modelling

We utilise groundwater flow models to inform water resource management, schemes and planning by simulating current conditions and predicting the effects of land-based activities.  Our groundwater modelling specialists develop site-specific conceptual and detailed models such as the SWAT model for surface water catchments and the WAVE Modflow and MT3D for groundwater.  We model the contaminant and its impacts on receptors.  The resulting applications allow us to evaluate and predict contaminant migration, dewatering, potential human health impacts, and design mitigation solutions.

Assisting the Waste Management Industry

We complete detailed hydrogeological risk assessments for the planning and environmental permitting of new landfill sites.  Our hydrogeological risk assessments ascertain the necessary pumping activities and permits needed to dewater quarry sites before commencing a new development.  We complete geological and hydrogeological risk assessments to support planning applications for Energy from Waste facilities and for extractive mineral activities.

Meeting Monitoring Requirements

We help our clients meet the monitoring requirements set out in their environmental permits and discharge consents through monitoring programmes.  Our specific water quality sampling services of groundwater and surface water combines chemical, biological and toxicological assessments to support compliance.  Landfills are required by legislation to periodically review hydrogeological risks to ensure that original site risks and groundwater risk assessments are valid, and we report to the relevant authority on behalf of the client (required by UK regulators, the Environment Agency, the Scottish Environmental Protection Agency, National Resources Wales and the Northern Ireland Environment Agency.)

Landfill Leachate and Surface Drainage

We also provide risk assessments for discharges to surface water from landfill leachate and surface drainage.  Our knowledge of leachate composition also allows us to consider, outline, and design treatment options to minimise the impact of discharges on surface water and provide long-term sustainable management solutions.

Design and Mitigation Schemes

We design passive treatment systems that provide long term solutions to low concentration but environmentally significant pollutants including the design of reed beds for the treatment of weak landfill leachate to complex wetland constructions that remove nitrogen from sensitive waters in chalk streams in Hampshire.