Monitor and report your performance

What you need to monitor and how to report your performance to meet your permit conditions.

This guide explains the monitoring and reporting you must carry out if you have a landfill permit.

You must monitor:

  • when you plan your site – to get baseline environmental data
  • during operation – to make sure you comply with your permit
  • during aftercare – to make sure you comply with your permit and so that you can surrender it

You must send the Environment Agency information about your site’s performance. The Environment Agency will use this information to check that you’re complying with your permit conditions. Your permit will include details of what you need to report on.

You must also read the guide control and monitor emissions for your environmental permit.

Design your monitoring plan

You must include an emissions monitoring plan with your environmental permit application. The Environment Agency will need to approve your monitoring plan when they assess your application.

You must:

  • design your monitoring plan based on your conceptual site model and to the requirements of this guide
  • monitor to meet a specific objective
  • use techniques and infrastructure that are fit for purpose, for example install separate boreholes for monitoring landfill gas and groundwater to prevent conflicts between the objectives of the monitoring
  • use the monitoring data to review the validity of your conceptual site model and the design assumptions you made during planning and development
  • interpret the monitoring data clearly and appropriately on a regular basis

You must consider:

  • what you need to monitor, including any standard reference methods and sampling protocols
  • your monitoring strategy – how you select your monitoring points and optimise your monitoring
  • background concentrations, including contributions from other sources
  • uncertainty around the monitoring method and the overall uncertainty of measurement
  • quality assurance and quality control protocols, such as equipment calibration and maintenance, storing samples and audit trail
  • reporting procedures, storing data, interpreting and reviewing results and the reporting format for providing information

What you need to monitor

Your permit will tell you what you need to monitor. This will be specific for your site and include, where relevant:

  • leachate
  • point source emissions
  • groundwater
  • landfill gas
  • surface water
  • particulate matter

You must monitor to:

  • demonstrate the landfill is performing as designed and in accordance with your risk assessment predictions
  • show that management and control systems are preventing pollution
  • show compliance with the emission and compliance limits set in your permit
  • identify where further investigation is needed and, where risks are unacceptable, the need for measures to prevent, reduce or remove pollution
  • identify when a site no longer presents a risk of pollution

Carry out topographic surveys

You must carry out a topographic survey of the site:

  • once a year
  • before you dispose of waste in any new cell or new development area of the landfill
  • after you complete part or all of the landfill
  • before and after you restore your landfill – if you restore your site using waste

You must get written agreement from the Environment Agency before you stop the topographic surveys.

Accuracy of the topographic survey

You must construct and maintain a network of stable, permanent survey stations to control all survey work around the site. The survey stations must be referenced to Ordnance Survey National Grid coordinates. You must meet the following requirements - the:

  • grid alignment must be accurate to within 1 metre
  • horizontal accuracy must be at least 1 metre in 20,000 metres
  • level values of the stations must be accurate to within 20mm

Where you propose to use an alternative method to carry out the topographic survey, you must agree this in writing with your local Environment Agency officer.

If you use different references previously agreed with the Environment Agency, you should continue to use them for consistency.

You must mark the location of all monitoring stations on a plan. The plan produced by the topographic survey must:

  • be an appropriate scale (such as 1:1250) to show the surveyed features of the landfill
  • include 1 metre contours
  • include the landform or an indication of the landform immediately adjacent to the landfill
  • include all roads, engineering structures, boundaries, monitoring points, extraction points, landform features and all other relevant site features in the permitted area
  • include significant landform changes such as embankments or stockpiles

Set assessment levels and compliance limits

You must set assessment levels and propose compliance and emission limits in your permit application.

Assessment levels

Assessment levels are levels you use to decide whether your site and its pollution control systems are performing as you planned.

You must use them to identify negative trends in the monitoring data. You must then take appropriate action to prevent the breach of a compliance limit.

Assessment levels for groundwater are called control levels.

Compliance limits

Compliance limits and emission limits are concentrations that the Environment Agency will put in your permit.

If you exceed these limits you have breached your permit. The Environment Agency will record this as non-compliance and may take enforcement action against you.

Compliance limits for groundwater are called trigger levels.

Plan your monitoring points

You must determine the number, design and location of your monitoring points based on your conceptual site model and risk assessments.

You must refer to the following guidance to demonstrate your monitoring points are suitable:

You must review the location and construction of monitoring points and infrastructure to make sure they remain fit for purpose. Your monitoring plan must include details of how you will do this and how you will replace any damaged or unusable monitoring points.

What to include in your monitoring plan

You must describe the technical specification for all landfill monitoring. This must be specific for your site.

Your plan must include:

  • a summary of your risk-based approach to monitoring
  • the design and location of your monitoring infrastructure
  • baseline or background data
  • the type of monitoring you will carry out
  • the methods of monitoring – including detection limits and accuracy
  • monitoring locations
  • monitoring frequency
  • assessment levels and proposed compliance limits
  • action plans that you will implement if you exceed any assessment levels, emission limits or compliance limits
  • your quality assurance and quality control procedures for the construction of your monitoring infrastructure and your methods of sampling, laboratory analysis, data handling, interpretation and reporting

Monitoring and extraction point plan

You can identify your monitoring locations on a drawing or plan. For landfills for hazardous or non-hazardous waste, this is called a monitoring and extraction point plan (MEPP). For landfills for inert waste, this is called a monitoring point plan (MPP).

If you add new monitoring points at your site, you can include these on your MEPP or MPP and send it to the Environment Agency each year with your annual report. You do not need to change (vary) your permit to add the new locations to the monitoring schedules of your permit.

If you want to remove points from your MEPP or MPP that have an emission or compliance limit, you will need to apply to vary your permit. You must get the Environment Agency’s agreement in writing if you want to remove points from your MEPP or MPP that relate to ‘other monitoring’ in your permit.

If you decide not to provide a MEPP or MPP, your permit will include specific monitoring locations. You will need to apply to vary your permit if you want to add or remove monitoring points.

Continuous monitoring

If you carry out continuous monitoring you must follow these requirements.

Continuous monitoring: get approval

Before you start using a continuous monitoring system you must send your local Environment Agency officer details of the system. This is to reduce the risks of uncertainty in the use of the system and any data it produces.

You must include:

  • system components and suppliers
  • system performance standards
  • calibration standards and procedures

You must identify other associated elements of data collection that may not be linked to the continuous monitoring system. For example, leachate level monitoring wells that are manually dipped.

The Environment Agency must agree your proposal before you start continuous monitoring.

Continuous monitoring: manage your data

You must properly manage the data that your continuous monitoring system produces.

The Environment Agency will not compare each data point against a compliance limit. They will assess compliance against the relevant environmental objective based on the relevant monitoring frequency in your permit. For example, the average leachate level over a reporting period.

Continuous monitoring: data reporting

Your data reports must include:

  • the average result for the period
  • the maximum result for the period
  • a measure of the variance in the results – expressed as the 95 percentile confidence interval
  • the availability of the monitoring system – expressed as a percentage of the time when the system produced data
  • justification of all data that you have removed as being either a false reading or an outlier

The availability of the monitoring system data must be 95% or greater.

If the availability is less than 95% you must report:

  • how you have investigated the shortfall
  • how you will avoid a recurrence
  • an estimate of the data during the period when monitoring was not taking place and the impact on the results

The Environment Agency may require you to revert to more traditional monitoring techniques if you regularly fail to meet the 95% availability requirement.

Continuous monitoring: compliance assessment

Where your continuous monitoring data indicates a breach of a compliance limit for any monitoring period, you must notify the Environment Agency.

Where the Environment Agency agrees that you can use a continuous monitoring system you must review your accident management plan. Your plan must reflect any additional time and resources you need to identify and examine the cause of a non-compliance.

Continuous monitoring: reporting period

Your permit will state how often you must send your summary data to the Environment Agency.

You must report your data in a table. This must show the real time data over the reporting period, variations and any developing trends.

Your permit will state how long you need to keep the real time data.

Monitoring at boreholes

You must prepare a specification and construction quality assurance (CQA) plan for the construction of your groundwater and landfill gas monitoring boreholes. You must follow the guidance for CQA. Where you propose to drill into waste you must also follow the guidance for drilling into waste on landfill sites.

During monitoring visits for each borehole you must:

  • record the relative pressure in any landfill gas monitoring borehole
  • record the depth to water or leachate in any borehole dedicated to such monitoring
  • check the overall depth to the base of the borehole or well each year to assess if it is becoming silted up or blocked

Monitoring on land off site

Where your permit requires you to monitor or do other works on land outside of your control, the landowner must give you permission to access this land to comply with your permit conditions.

The landowner is entitled to compensation from you for any loss or damage, as set out in schedule 5, part 2 of the Environmental Permitting Regulations 2016.

Keep records and review your monitoring plan

Make someone responsible for the plan

You must identify who is responsible for the plan and have the management structure in place to implement it.

Keep records

You must keep records of all monitoring. This includes records of:

  • taking and analysing samples
  • instrument measurements and calibrations
  • examinations, tests and surveys

Your permit will tell you what records you must keep until you surrender your permit.

Appropriately trained and competent staff must carry out your monitoring. You must keep a record of their qualifications and experience.

Review your monitoring plan

You must analyse your monitoring data and review the monitoring plan each year against:

  • your monitoring objectives
  • the emission and compliance limits
  • the conclusions made in your risk assessments

You must revise your monitoring plan based on this data review to make sure it remains appropriate. You must submit any changes to your monitoring plan to your local Environment Agency officer for their written agreement.

Monitor groundwater

You must monitor both the groundwater level and the concentration of potential pollutants within the groundwater. You must do this for all landfills for hazardous or non-hazardous waste and for landfills for inert waste in a sensitive setting. Our groundwater protection guidance may refer to this as requisite surveillance.

You must have monitoring points:

  • up-gradient of the landfill site, in the groundwater inflow region – at least one measuring point
  • down-gradient of the landfill site, in the outflow region – at least 2 measuring points

The up-gradient monitoring will give you background data. The down-gradient monitoring will identify breaches of compliance limits. You must increase the number of monitoring points where this is required by your hydrogeological risk assessment.

If the results of your down-gradient groundwater monitoring are above the compliance limit, you must resample the groundwater. This is to confirm the original result. You must notify the Environment Agency of the original result.

Where the additional sample confirms the breach, you must prevent or minimise any further emissions. Where the additional sample confirms that the original result was an error you must notify your local Environment Agency officer. This is so that they can amend their records and suspend any compliance score.

You must follow the guidance for groundwater risk assessments and the principles of monitoring.

Minimum reporting values for hazardous substances

The minimum reporting value (MRV) is the lowest concentration of a substance that a laboratory can achieve with current analytical equipment. The laboratory must report this in the results of an analysis.

You must report groundwater monitoring data for hazardous substances to an MRV. The MRVs are defined as the limit of quantification. Find the limit of quantification for hazardous substances in table 1 of the technical Report on Groundwater Hazardous Substances on the UK Technical Advisory Group on the Water Framework Directive website.

Monitoring boreholes at landfills for hazardous or non-hazardous waste

For landfills for hazardous or non-hazardous waste, you must have at least one borehole every 100 metres along the down-gradient site boundary at engineered containment sites where any leaks of leachate are likely to be diffuse.

You must have at least one borehole every 50 metres along the down-gradient site boundary at engineered containment sites:

  • where leachate could leak from holes or tears in a geomembrane over a restricted area
  • located above fissured strata
  • where there is no leachate detection layer or it’s not working

Monitoring boreholes at landfills for inert waste

For landfills for inert waste your risk assessments will identify whether you need to monitor groundwater. Where you do, you must propose the number and spacing of groundwater monitoring boreholes in your permit application. This must be based on your conceptual site model and risk assessment.

Plan your monitoring boreholes on site boundaries

The monitoring boreholes must be as close as possible to the edge of the waste mass to give you an early warning of emissions to groundwater. They must be located where they intercept emissions from the landfill. This must be no more than 100 metres from the waste boundary.

Where there is more than one groundwater horizon beneath your landfill, you must install your boreholes to monitor all the groundwater receptors you identified in your conceptual site model. Any borehole you install must not allow groundwater to flow between groundwater horizons.

Your permit will tell you how often you must measure the level of groundwater.

Additional boreholes if you have receptors at risk

You must have at least one monitoring point on any pathway between the landfill site and a sensitive water receptor. Your risk assessment will identify any sensitive water receptors.

Monitor surface water

If you have a point source discharge of surface water from your landfill to a controlled water, your permit application must include:

Controlled waters are defined in section 104 of the Water Resources Act 1991.

Your permit will list the parameters you must monitor and the compliance limits.

You must monitor the concentration of potential pollutants in surface water in any water body at risk from your landfill.

Plan your surface water monitoring points

You must use your risk assessment to determine the most appropriate number and location of monitoring points.

For flowing water, you must monitor from at least 2 surface water monitoring points, one upstream and one downstream of the landfill site.

Where surface waters are sensitive to small changes in water quality (for example wetlands), you may need to monitor at more than 2 locations. Use your risk assessment to identify the appropriate number.

The upstream value will provide background quality. You can compare downstream quality with these values. If the downstream values are higher than the upstream values you must investigate whether that is due to emissions from your site. If it is, you must take appropriate measures to prevent the emission.

You must have at least one monitoring point for each area of ponded water, wetland or lake that you identify as being at risk. These might be within the site boundary or within the down-gradient catchment area of the site.

Your monitoring plan must include evidence to justify the distance between surface water monitoring points. In flowing water, this must consider the hydraulic characteristics of the watercourse.

Based on your risk assessment, you may need to take biological measurements. For example, to identify the impact of specific organisms on water resources or indicator measures of biotic communities that are used to classify the quality of the watercourse.

Monitor landfill leachate

For landfills for hazardous or non-hazardous waste, you must monitor the level of leachate within any contained landfill to determine the:

  • level of leachate at the base of each landfill cell
  • level of leachate next to the site boundary

Use the monitoring data to:

  • confirm compliance with the maximum levels allowed in your permit
  • assess how effective your leachate management and extraction systems are in meeting your design
  • update your design calculations, and improve the operation and maintenance of your systems
  • identify potential for overspill of leachate to surface waters or the potential for lateral seepages into groundwater

You must monitor the concentration of potential pollutants in the leachate and assess how it varies in space and time within the body of the landfill. You must:

  • identify specific chemical characteristics of the leachate – so that you can assess the potential risk of each parameter on groundwater and surface water
  • assess the state and rate of stabilisation of the waste body to compare with the design lifetime of the containment and monitoring systems
  • monitor the concentration of potential pollutants in the leachate before it is treated or discharged
  • provide evidence that the potential pollutants in the leachate have reduced to acceptable concentrations (completion criteria) when you apply to surrender your permit

Monitor leachate within your storage and treatment system

You must monitor the level, flow and concentration of potential pollutants in the leachate and how it varies in time. Within leachate storage and treatment systems, you must:

  • monitor the level of leachate in a storage lagoon to prevent overflow
  • monitor the volume of leachate you discharge from the storage and treatment system
  • identify the specific chemical characteristic of leachate that you need to meet before you discharge from storage lagoons and treatment systems

Monitoring frequency for leachate

Your permit will tell you how often you must monitor in-waste leachate levels and quality. You must normally monitor levels once a month when your landfill is operational. You may be able to reduce monitoring during aftercare based on a risk-based monitoring review.

You must normally sample leachate and analyse its composition once every 3 months when the landfill is operational. You may be able to reduce this frequency after a cell or phase is capped based on a risk-based monitoring review.

Plan your leachate monitoring points

For each cell or hydraulically separated area of the site you must have:

  • at least 2 level monitoring points
  • a collection sump

Points for monitoring leachate levels must be away from leachate drainage pipework and pumping systems.

Your monitoring must confirm the level of leachate across the cell or leachate catchment area. You must extract leachate to prevent levels from rising above permitted compliance limits.

You may need additional monitoring points and controls where you cannot keep leachate levels (perched or otherwise) below the compliance limit. For example, where there is a threat or incidence of overspill to surface water or of lateral seepage to groundwater.

If a monitoring point fails and you cannot monitor levels from it, you must replace it. The Environment Agency will consider a risk based justification for non-replacement. This must consider future risks of extraction system failure, for example through blockage or fouling.

Monitor landfill gas

Monitor background gas during site preparation

For landfills for hazardous or non-hazardous waste, you must collect monitoring data for background gases before and during site preparation. Use this data to:

  • develop your conceptual site model and landfill gas monitoring plan
  • work out background concentrations
  • identify whether there are other sources of methane (CH4) and carbon dioxide (CO2) at the site

You must monitor the following parameters during the site preparation phase:

  • CH4
  • CO2
  • oxygen (O2)
  • atmospheric pressure

You must record what the weather was like during each monitoring visit. This includes temperature, rainfall and ground conditions, for example if the ground is waterlogged, frozen or covered in snow.

You must collect 12 data sets that are representative of a 12-month period. Representative means that you collect data during a range of conditions, including when atmospheric pressure is rising and falling.

Monitor landfill gas once your site is operational: landfills for inert waste

For landfills for inert waste, you must monitor for landfill gas within the waste. This is to confirm that you have only accepted inert waste and no biodegradable waste.

You must install a minimum of 2 boreholes per cell, or 2 per hectare. You must install these as soon as each cell or area of the site is complete.

You can rely on searcher bar (also called spike test) monitoring where the total depth of the waste is less than 4 metres or before each cell or development area is complete. You must not use a searcher bar once you have restored a cell or development area.

Monitor landfill gas once your site is operational: landfills for hazardous or non-hazardous waste

For landfills for hazardous or non-hazardous waste, you must monitor the concentration of trace components within the landfill gas. You must use this data to:

  • develop source term values for a site-specific risk assessment of gaseous emissions and the resulting gas management plan
  • develop source term values for gas generation models such as GasSim
  • provide compositional data for the annual review and refinement of the current gas management plan

You must monitor to make sure the input parameters, emissions and assumptions in your conceptual site model are all realistic.

Your risk assessment must inform your monitoring strategy to:

  • validate the assumptions made in the risk assessment, such as trace gas composition and gas generation rates
  • identify places where there may be uncontrolled emissions, such as well heads, pipework, engines, flares and surface flux
  • confirm any off site migration through the ground or to the atmosphere

You must monitor:

  • gas concentrations within the waste
  • the efficiency of the gas extraction system
  • atmospheric pressure during borehole and well monitoring

You must use your monitoring data to review your GasSim model for the site every year.

Monitoring frequency for landfill gas

Your permit will specify how often you must monitor. It will depend on the:

  • age of your site
  • type of waste you accept
  • geology of the surrounding strata
  • control measures installed
  • potential risk from migrating gas
  • sensitivity and proximity of surrounding development and receptors
  • results of previous monitoring

Monitor landfill gas: emissions without a compliance limit

For landfills for hazardous or non-hazardous waste, you must consider emissions of substances not controlled by a compliance limit in accordance with your permit conditions and management plan.

For all cells that have accepted biodegradable waste, you must monitor CH4 emissions through the cap. You must use a 2-stage approach:

  1. A survey to identify faults in the gas containment and collection system. You must locate and fix these.
  2. Measure the flux of CH4 emitted through the intact cap at representative points.

The Environment Agency’s standards for gas emission from a landfill surface are expressed as the average flux of CH4 from the surface of the cap in each zone.

The emission standards are:

  • permanently capped zone: 0.001 mg/m2/second
  • temporarily capped zone: 0.1 mg/m2/second

Where any zone or feature exceeds these concentrations, you must:

  • use the results of the surface emission survey to review your gas management plan
  • take action to reduce the emissions and bring the whole capped area of the landfill site within the emissions standard
  • identify local emission sources, quantify them and, if necessary, remediate

If monitoring identifies variability in the cap and a high uncertainty in the calculation of flux, you must include an improved monitoring procedure in your gas management plan for your next surveys.

Regular reports

You must report your monitoring data to the Environment Agency to show whether:

  • your management system and environmental protection measures are working
  • you are meeting your compliance limits

Your permit conditions and schedules will tell you:

  • what you must monitor
  • how often you must monitor
  • when you must report

Where your permit requires you to report leachate levels, the Environment Agency will will score every non-compliance. This is to comply with their assessing and scoring compliance policy. They will apply a risk category and score for the average level at each monitoring point for a calendar quarter.

Report on waste

You must report on how much waste you have:

  • accepted for disposal and recovery – including the types of waste
  • removed from the site – including leachate removed by tanker

Your report must include evidence of your compliance with a relevant competency scheme.

Your permit will tell you when you must send this report to the Environment Agency.

Annual report

Your permit conditions will tell you whether you need to send the Environment Agency an annual report.

Once your site is definitely closed you only need to send a report every 3 years.

Your report must include:

  • a summary of the previous year’s progress against improvement targets
  • improvement targets you plan for the coming year
  • an assessment of your monitoring data – include a description of any trends, assessment level or compliance limit breaches and problems with individual monitoring points
  • a summary of the results of any waste validation (level 3) testing you have carried out
  • a topographic survey to show the structure and composition of the landfill body – use this survey and your previous survey to calculate the void space taken up, the remaining void space and the settlement behaviour of the waste

For landfills that are installation activities (listed in schedule 1, section 5.2 of the Environmental Permitting Regulations 2016 you must also include:

  • the energy consumed on site
  • the quantity of water used
  • what you have done to improve energy efficiency and water use
  • summary data for the annual production and treatment of landfill gas and leachate

You must provide your annual report by 31 January each year unless the Environment Agency has agreed to accept it on another date.

Where your permit requires it, you must always provide the volume of landfill gas extracted and utilised by the end of February each year.

Changes to monitoring points

If you have added new monitoring or extraction points, your annual report can include an updated MEPP or MPP to show the location of both these and your existing monitoring and extraction points.

Review your risk assessments

When you assess the monitoring data for your annual report, you must check the data confirms the assumptions you made in your risk assessments.

You must include:

  • the volume of gas collected and compare it to that predicted in the current GasSim (or other agreed model) – include, where applicable, an explanation of the difference
  • concentrations of potential pollutants in the leachate and compare it to those predicted in your hydrogeological risk assessment (HRA)
  • concentrations of potential pollutants in the groundwater and trends, and compare these to those predicted in your HRA

You do not need to carry out a full review of your HRA each year. You must highlight any trends in the concentration of potential pollutants against the previous risk assessment to inform the 6-yearly HRA review.

Where you have compliance limits in your permit schedules, you must also include:

  • concentration of potential pollutants in surface water discharges and trends, and compare it to those predicted in your risk assessment
  • noise, odour, dust, pests and other amenity issues and compare them with those you predicted in your risk assessment

Where your data does not confirm the assumptions you made in your previous risk assessments, you must reassess the risk using the data you have collected. Where the results of this revised assessment suggest an increased risk of pollution you must notify the Environment Agency.

Where you cannot reduce the risk of pollution and cannot comply with a compliance limit, you may need to apply to vary your permit. That application must include a revised risk assessment.

Report leachate volume

Your permit conditions and schedules will tell you what leachate volume information you need to send to the Environment Agency. You must normally send one or more report for leachate volume:

  • treated on site – this includes leachate imported from other sites
  • recirculated into the waste
  • discharged to sewer or taken off site by road tanker

You must use this data to confirm whether:

  • there is sufficient leachate storage capacity on site
  • leachate is being extracted at optimum rates to maintain permitted levels

Your annual report must confirm any operational improvements you plan to make next year.

Report surface water volume

Your permit conditions and schedules will tell you what surface water information you need to send to the Environment Agency. You must normally report surface water volume:

  • treated on site – this includes active settlement
  • discharged to surface water

You must use this data to confirm whether:

  • there is sufficient surface water storage capacity on site
  • treatment is effective

Where necessary, your annual report must confirm any operational improvements you plan to make next year.

Report landfill gas volume

Your permit conditions and schedules will tell you what landfill gas information you need to send to the Environment Agency. You must normally send figures for the annual landfill gas volume:

  • combusted in an engine
  • combusted in a flare
  • used in some other way, for example for vehicle fuel or fed into the national grid

Where necessary, your annual report must confirm any operational improvements you plan to make next year.

Review your hydrogeological risk assessment every 6 years

Where your permit requires it, you must review your HRA every 6 years. Your permit will tell you when you need to submit the review to the Environment Agency.

If your environmental permit requires a 4-yearly review, you should read this to now mean 6-yearly. The review is due on the sixth anniversary of the original issue date of your permit and every subsequent 6 years.

You must review your leachate management plan (LMP) to confirm that it remains applicable for your site. You must confirm that the LMP adequately represents the input parameters of your current HRA model and that there have been no changes to your LMP since your last HRA review or your original HRA. You must confirm:

  • that you are monitoring for appropriate substances present in the leachate
  • the number and location of leachate extraction and monitoring points
  • that you manage cells or phases as per your current HRA model
  • whether you have started or ceased leachate recirculation

Where leachate quality matches the input parameters previously modelled you will not need to change your permit. This includes where the:

  • model included a range of values as a probability distribution function (PDF)
  • review confirms that substances present in the leachate are being monitored for in groundwater, normally a list of surrogates

Where leachate quality does not match the input parameters previously modelled, you must run a revised model using appropriate input parameters to confirm the potential impact. This includes where the:

  • values fall outside the previously modelled PDF values
  • review suggests that critical substances are present in the leachate but are not being routinely monitored for in groundwater

You must confirm:

  • what impact the results of your re-modelling exercise will have on groundwater or surface water quality
  • if you intend to change site operations
  • if you intend to put additional measures in place to mitigate any unacceptable discharges

You must apply to vary your permit where your re-modelling requires a change to any element of the compliance limit, for example:

  • the location of compliance monitoring points
  • the chemical substances monitored
  • monitoring frequency

If your HRA review concludes that there is no predicted impact or the model suggests that there will be no impact, you will not need to vary your permit.

For more information read the guide on HRA review for a landfill site.

When you need to notify the Environment Agency

Your permit conditions will tell you when you must formally notify the Environment Agency and how quickly you must do so.

You must notify the Environment Agency within 24 hours when:

  • you breach a permit condition
  • there is an accident or incident on site that significantly affects or may significantly affect the environment

When you do not need to notify the Environment Agency immediately your permit will tell you how soon after the event you must tell them.

Examples of accidents or incidents that may occur at a landfill include:

  • damage to a lining system where waste or waste products could be released
  • leachate or surface water storage lagoons or tanks overtop
  • a fire on site, including within the waste
  • you receive complaints or have problems controlling amenity issues such as odour, noise, dust, birds or other pests

To notify the Environment Agency call the incident hotline on 0800 807 060.

You must send the Environment Agency a written plan explaining how you will bring the site back into compliance with your permit conditions and mitigate any significant affect.