Wear management catchment: baseline length of rivers and estuaries polluted by abandoned metal mines
Published 12 March 2025
Applies to England
© Crown copyright 2025
This publication is licensed under the terms of the Open Government Licence v3.0 except where otherwise stated. To view this licence, visit nationalarchives.gov.uk/doc/open-government-licence/version/3 or write to the Information Policy Team, The National Archives, Kew, London TW9 4DU, or email: psi@nationalarchives.gov.uk.
Where we have identified any third party copyright information you will need to obtain permission from the copyright holders concerned.
This publication is available at https://www.gov.uk/government/publications/abandoned-metal-mines-in-england-baseline-length-of-rivers-and-estuaries-polluted-by-harmful-metals/wear-management-catchment-baseline-length-of-rivers-and-estuaries-polluted-by-abandoned-metal-mines
This is one of 20 reports, one for each polluted management catchment, on the water quality monitoring undertaken by the Environment Agency to determine the baseline length of rivers and estuaries considered polluted by any of the Environment Act target substances from abandoned metal mines in 2022.
A length of river or estuary is considered polluted where the concentration of one or more of the 6 target substances (arsenic, cadmium, copper, lead, nickel and zinc) exceeds the relevant Environmental Quality Standard (EQS). EQS concentrations are based on ecotoxicology data and set by government at a level that should prevent harmful environmental impacts. When the concentration of a substance in a water sample is higher than the EQS, adverse impacts on the aquatic ecosystem can be expected. The relevant EQS for each target substance are set out in The Water Framework Directive (Standards and Classification) Directions (England and Wales) 2015.
The purpose of calculating this baseline was to enable measurement of the statutory abandoned metal mines target set out in Part 4 of the Environmental Targets (Water) (England) Regulations 2023. This regulation requires that the combined length of English rivers and estuaries polluted by the target substances from abandoned metal mines is, by 31 December 2038, at least 50% lower than the baseline.
In the Wear management catchment, the baseline length of polluted rivers for the abandoned metal mines water target is 86km. We will aim to identify the key sources of metal pollution in this management catchment by carrying out detailed monitoring investigations.
You can find further background and context on the Environment Act abandoned metal mines water target in the national baseline report which should be read together with this report.
The Wear management catchment
The Wear management catchment covers an area of approximately 2,940km2 and encompasses areas of the North Pennines National Landscape. Go to Wear Management Catchment on the Catchment Data Explorer for an interactive map showing the 6 operational catchments that make up the Wear management catchment.
Metal mining in the Wear management catchment
The rich metal ore deposits in the headwaters of the Tyne, Wear and Tees catchments meant that in the 1800s, the North Pennines was one of the heavily industrialised upland landscapes in England.
Mining in Weardale was sporadic until the early 1800s when several mines came into operation. These mines were worked for lead until the market crashed in the early 1900s. Unlike mines in neighbouring areas, the mining focus was able to switch from lead to fluorspar. This allowed production in Weardale to continue right up to the end of the 20th century. Major mining operations started at the Grove Rake mine in the early 1800s, initially extracting ironstone before production moved to lead ore. Finally, from the 1930s, the mine was worked for fluorspar before finally closing in December 1999. For more information, please visit North Pennines - Northern Mine Research Society or OREsome project - Middlehope Shield and Low Slit mines – North Pennines National Landscape.
Figure 1 shows the locations of mineral veins, known mine water discharges, closed mine waste facilities known to be causing serious environmental harm, and areas of abandoned mine wastes (mining spoil) in the Wear management catchment.
This information has been gathered from various sources including:
- BGS Geological mapping - GeoIndex - British Geological Survey
- Prioritisation of abandoned non-coal mine impacts on the environment
- Inventory of closed mining waste facilities causing serious environmental impacts
- Defra-funded ‘Source apportionment of pollution from non-coal mines’ research project by Newcastle University and Hull University (unpublished)
- Environment Agency water quality data archive
As we can see in Figure 1, the historical mining activities in the Wear management catchment are concentrated in the Wear Upper and Middle operational catchments.
Figure 1. Map showing the abandoned metal mines, mineral veins and baseline river monitoring sites in the Wear management catchment
© Environment Agency
The tables below list the catchments (surface water bodies) polluted by abandoned metal mining in the Wear management catchment. The tables highlight known point sources (mine adits or mine drainage levels) and diffuse sources (mine wastes or spoil) within the catchment. The Environment Agency is continuing to investigate point and diffuse sources within the Wear management catchment by undertaking a series of catchment characterisation studies over the next 5 years. This will help us identify which sources need to be tackled to achieve the long-term statutory target.
Wear Upper operational catchment: sources of metal pollution
Table 1 summarises which type of pollution sources from abandoned metal mines have been identified within the catchments (surface water bodies) in the Wear Upper operational catchment.
Table 1. Summary of metal pollution sources in the Wear Upper operational catchment
| Catchment (Surface water body) | Point sources of pollution | Diffuse sources of pollution |
|---|---|---|
| Bollihope Burn from Source to Wear | Yes | Yes |
| Rookhope Burn from Source to Wear | Yes | Yes |
| Kilhope Burn from Source to Wear | Yes | Yes |
| Stanhope Burn from Source to Wear | Yes | Yes |
| Wear from Wearhead to Middlehope Burn, Iresho | Yes | Yes |
| Wear from Middlehope Burn to Houselop Beck | Yes | Yes |
| Middlehope Burn from Source to Wear | Yes | Yes |
Wear Middle operational catchment: sources of metal pollution
Table 2 summarises which type of pollution sources from abandoned metal mines have been identified within the sub-catchments (surface water bodies) in the Wear Middle operational catchment.
Table 2. Summary of metal pollution sources in the Wear Middle operational catchment
| Catchment (Surface water body) | Point sources of pollution | Diffuse sources of pollution |
|---|---|---|
| Euden Beck Catchment (Trib of Bedburn Beck) | Yes | Yes |
| Bedburn Beck from Euden Beck to Wear | None identified: sources are upstream | None identified: sources are upstream |
Baseline monitoring
The objective of the baseline monitoring was to establish the upstream and downstream extent of surface waters polluted by the target substances from abandoned metal mines. We selected the baseline monitoring sites by first completing a desk study to review previous water quality data, maps and reports. We then made initial site visits to collect samples and to assess the suitability of the site for continued sampling. Generally, at least twelve water quality samples were then collected from each monitoring site.
Within the Wear management catchment, water quality monitoring was undertaken in 2 of the 5 operational catchments. These catchments are highlighted in Figure 1. We did not carry out monitoring in operational catchments where there is either no historical metal mining within the catchment or a combination of current and historical monitoring data shows that waterbodies within these catchments are not polluted by abandoned metal mines.
In total, 53 monitoring sites were selected across the Wear management catchment to determine the baseline length of rivers polluted by target substances from abandoned metal mines. The locations of these monitoring sites are shown in Figure 1.
Water quality data collected between 1 January 2022 and 31 March 2024 have been used to determine and validate the baseline length of rivers and estuaries considered polluted in 2022. The length of rivers polluted by abandoned metal mines fluctuates in response to natural variation in rainfall and river flows. However, this length will not materially change unless remediation measures like mine water treatment schemes or diffuse interventions are installed to decrease inputs of metals. Therefore, data collected after 31 December 2022 are considered to be representative of rivers, provided no new remediation measures had been constructed since 2022. Where new remediation measures have been constructed in the Wear management catchment since 2022, the baseline was determined only using water quality data collected before these measures were completed.
Water quality monitoring results
In the Wear management catchment, the target substances measured were cadmium, copper, lead, nickel and zinc. We did not undertake testing for arsenic in this management catchment since historical monitoring data and knowledge of the local geology across the catchment indicated that no rivers are polluted by arsenic in this management catchment.
The baseline water quality data for all monitoring sites are available on the Environment Agency’s public water quality archive.
For a river water quality sample to be considered polluted, concentrations of one or more of the target substances must exceed the relevant Environmental Quality Standards (EQS) set by government when assessed as an “annual average”. The EQS are set out in The Water Framework Directive (Standards and Classification) Directions (England and Wales) 2015.
The EQS are derived using ecotoxicology data and set at a level that should prevent harmful environmental impacts. When the concentration of a substance in a water sample is higher than the EQS, adverse impacts on the aquatic ecosystem can occur, and the sample is considered to be polluted.
To understand the severity of pollution, we calculated a numeric “pollution level” by dividing the measured concentration of the target substances by the EQS. If the pollution level is greater than 1, the monitoring site is considered polluted by that target substance. Therefore, the higher the numeric pollution level, the greater the likelihood of harm to aquatic life.
Baseline polluted river length: Wear management catchment
Our detailed monitoring across a range of flow conditions between January 2022 and March 2024 shows that in the Wear management catchment, the baseline length of polluted rivers for the abandoned metal mines target is 86km.
Figure 2 shows the rivers in the Wear management catchment that are polluted by target substances from abandoned metal mines.
Figure 2. The baseline length of rivers polluted by target substances from abandoned metal mines in the Wear management catchment is 86km
© Environment Agency
Table 3 shows the river length (in km) that are polluted by each of the target substances within the Wear management catchment. In general, the most polluted rivers are impacted by more than one target substance.
Table 3. River length (in km) polluted by each of the target substances within the Wear management catchment
| Target substance | Polluted river length (km) | Pollution level: less than 3 times | Pollution level: 3 to 5 times | Pollution level: greater than 5 times |
|---|---|---|---|---|
| Cadmium (Cd) | 78 | 64 | 10 | 4 |
| Lead (Pb) | 40 | 25 | 11 | 4 |
| Nickel (Ni) | 0 | 0 | 0 | 0 |
| Zinc (Zn) | 74 | 50 | 18 | 6 |
| Copper (Cu) | 0 | 0 | 0 | 0 |
Rivers polluted by abandoned metal mines: Wear management catchment
Wear Upper operational catchment: baseline polluted rivers
Monitoring results show that the Wear Upper operational catchment is polluted by metals from the uppermost point of Kilhope Burn. This pollution continues along the length of the river for zinc and cadmium until the River Wear reaches Wolsingham. The river is marginally polluted as it passes the Broadwood Quarry sampling point near Frosterley but is not polluted by metals approximately 6km downstream at Scotch Isle Farm.
Several tributaries are also polluted, and contribute to pollution levels in the main River Wear, notably Rookhope Burn, Middlehope Burn, Sedling Burn and Daddryshield Burn.
Figure 3 shows the baseline polluted rivers in this operational catchment.
Figure 3. The baseline length of rivers polluted by target substances from abandoned metal mines in the Wear upper operational catchment is 70km
© Environment Agency
It should be noted that due to close proximity of some of the sampling points to each other, some of the sampling point markers on this map (blue squares) may overlap.
Wear Middle operational catchment: baseline polluted rivers
The main channel of the River Wear is not polluted by any of the target substances. However, one tributary, Euden Beck, has multiple sources of metals which pollute this stream from near its source, all the way to where the downstream water body, Bedburn Beck, joins the River Wear near Howlea Bridge.
Figure 4 shows the baseline polluted rivers in this operational catchment.
Figure 4. The baseline length of rivers polluted by target substances from abandoned metal mines in the Wear Middle operational catchment is 16km
© Environment Agency
It should be noted that due to close proximity of some of the sampling points to each other, some of the sampling point markers on this map (blue squares) may overlap.