Plan the environmental setting of your site
What you need to do when you start planning your landfill site.
This guide explains the risk assessments and background monitoring you must carry out.
You will need to show the Environment Agency that you will not pollute the environment where your site is located.
Landfill location
Your local waste planning authority decides where landfills will be located.
Landfill sites must have an environmental permit to control and manage their impact on the environment. The Environment Agency will only grant a permit when it’s satisfied that the landfill site design, development and operational activity will not pose an unacceptable risk to the environment.
Before you set up a new landfill site, you must apply for a bespoke waste environmental permit. Contact the Environment Agency if you want advice or a pre-application discussion.
As part of your permit application, you need to consider all the risks your site will present to the environment or human health. You can summarise these in a conceptual site model.
Where you operate a landfill, it is a groundwater activity where your operation might lead to a pollutant discharge to groundwater. Read groundwater risk assessment for your environmental permit.
Develop a conceptual site model
You must develop a conceptual site model to show that the design of your proposed site is suitable.
Your conceptual site model must:
- consider the location of your site in relation to any groundwater and surface water
- establish that you can develop your site to protect the environment
- establish background conditions at the site
- identify the potential impact of your site on local people and the environment
- develop a monitoring programme to confirm that there are no environmental impacts from emissions from the site and that your control measures are effective
- develop the engineering design for your site, including how you will manage any risks
You must use your conceptual site model to gather enough information to provide risk assessments and landfill design for your site.
Use the environmental setting and installation design report guide to develop your conceptual site model for landfills for hazardous or non-hazardous waste
Use the environmental setting and site design report guide to develop your conceptual site model for landfills for inert waste.
You must complete your groundwater risk assessment based on your conceptual site model.
Carry out site investigations
Your site investigation must include desk study and field investigations. The scale and extent of your investigations will depend on:
- the nature of the landfill, such as the types of waste it will accept
- how complex and sensitive the local environment is – for example the geology, hydrogeology and effects on people
- nearby receptors
You must follow the British Standard code of practice for ground investigations (BS 5930:2015+A1:2020). You must have clear identifiable objectives for each phase of the investigation.
Your investigations must include the site and surrounding areas that the landfill may affect.
You must carry out a site investigation where you need to:
- increase your understanding of the hydrogeological conditions at the site
- establish that the site is suitable for its intended purpose
- reduce uncertainty in your conceptual site model
A suitably qualified, trained and experienced geologist, hydrogeologist or geophysicist must do your site investigation. Their investigations should include:
- field observations of the proposed landfill development, geological exposures and hydrogeological features such as springs
- installation and logs of geological boreholes and groundwater wells
- in-situ testing of the soil beneath the site to determine geotechnical properties
- laboratory testing of soil and rock beneath the site to determine both the geotechnical and attenuating properties
- tracer tests, for example where groundwater flow is unclear or may be influenced by fracture pathways
- groundwater quality monitoring over time
- non-intrusive surface and down borehole geophysics
You must carry out a topographic survey for the site design and to calculate void space.
You must survey all borehole positions and other site features, for example streambeds, springs, outcrops and exposures.
You must record the position of each geological formation within the footprint of the landfill. You must determine the hydraulic and strength properties of each formation.
Your survey data should be in an electronic format so you can use it as part of your design process.
You can use aerial photographs to show the context of the site. Aerial surveys are useful in areas where access is difficult.
You must include site investigation data with your permit application or application to vary a permit to extend a site.
Complete risk assessments
Where your conceptual site model identifies that your landfill site presents a risk to groundwater or is in a sensitive location, you must complete risk assessments. These must show that any emissions from your site will not cause pollution.
Your risk assessments must include:
- impacts on amenity value
- landfill gas migration
- slope stability
- impacts on surface water
- impacts on groundwater
The Environment Agency will consider your risk assessments as part of the permit application process. It uses them to help decide whether to accept your proposed engineering protection, monitoring and compliance limits.
Sensitive locations
The Environment Agency considers a sensitive area for groundwater to mean:
- on or in a Principal aquifer or Secondary A aquifer
- below the water table – in any strata where the groundwater provides an important contribution to river flow or other sensitive surface water
- source protection zones 2 and 3
- in an area where groundwater provides a direct pathway to other sensitive receptors such as surface water, habitat sites or wetlands
Section E of the Environment Agency’s approach to groundwater protection explains their approach to landfills and their location.
Carry out a groundwater risk assessment
Your groundwater risk assessment must meet the requirements set out in what to include in your hydrogeological risk assessment.
Find out what you need to include in your hydrogeological risk assessment.
Landfills that accept hazardous or non-hazardous wastes will produce leachate that contains polluting substances. If you’re applying to accept these wastes, you must normally carry out a detailed quantitative risk assessment.
This must show that the leachate your landfill will produce will not pose an unacceptable risk to groundwater.
You can use your hydrogeological risk assessment to develop groundwater control levels and compliance limits for the landfill. Your hydrogeological risk assessment will help you decide how you will protect groundwater. This includes the engineering standards and other operational controls.
Where you need to carry out a detailed quantitative risk assessment you must justify the:
- selection and suitability of your model to represent all the scenarios, such as the different modelled phases of the lifecycle and potential impact of accidents and hydrogeological conditions
- confidence levels used within any stochastic modelling
- use of a particular computer model or software (including the version number), which includes relevance to the conceptual site model
- suitability of the model to identify and represent receptors and compliance criteria
You must send the Environment Agency an electronic copy of any model you use.
Your landfill will produce leachate throughout its operational and aftercare phases. The rate your site emits leachate and its quality will change over time. You must consider the durability and performance of any drainage, liner and capping systems. You must consider the:
- degradation of artificial lining systems (and other management systems, for example leachate collection, transfer, extraction, monitoring and treatment)
- capacity of the geological barrier to attenuate the discharge of leachate for the whole life of the landfill
- changing pollution potential of the leachate over time
You must include the hazardous substances and non-hazardous pollutants that are most likely to be in your leachate. Read, what to include in your hydrogeological risk assessment.
You may need to carry out a quantitative or qualitative risk assessment where your application is for a landfill for inert waste.
Geological barrier
Your conceptual site model and site investigation should show if there is a natural geological barrier at the base and up the sides of your site. The geological barrier must provide sufficient attenuation between the landfill and any potential groundwater receptor. Read design and build your landfill site.
Background monitoring
Your environmental permit application must include the initial design of your monitoring programme.
Where your risk assessment suggests there is a need, you will need groundwater and gas monitoring data before you start to accept waste at your site. This is so you can collect background (baseline) values to compare with the values you get when your site is operational. The Environment Agency normally requires at least 12 months of data before you start accepting waste. You must include background monitoring data with your permit application. You must continue to monitor around your site to confirm the impact it is having on groundwater throughout the life of the site.
Your monitoring must account for:
- seasonal fluctuations in groundwater levels
- atmospheric conditions when monitoring landfill gas
Where your permit conditions require it, you must carry out analysis for trace gas components and other testing to determine the origin of any background methane and carbon dioxide.
Site condition report
You must complete a site condition report for any area of the site that is not subject to waste disposal. See the requirements for site condition reports.
You must identify:
- the environmental setting and pollution history of the site
- any possible sources of historical contamination
- substances in, on or under the land, from materials currently used or produced by the activities under the permit that may be a pollution risk
- relevant plans for the site
You must collect and record information throughout the life of the permit.
You must update your site condition report and send it to the Environment Agency when you apply to surrender your permit.