Research and analysis

Eden and Esk management catchment: baseline length of rivers and estuaries polluted by abandoned metal mines

Published 12 March 2025

Applies to England

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 Eden and Esk management catchment, the baseline length of polluted rivers for the abandoned metal mines water target is 59km. 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 Eden and Esk management catchment 

The Eden and Esk Management Catchment covers an area of approximately 2,758km² and encompasses areas of the Lake District National Park, the North Pennines National Landscape and the Solway Coast National Landscape. Please go to Eden and Esk Management Catchment on the Catchment Data Explorer for an interactive map showing the 6 operational catchments that make up the management catchment. The boundary of the management catchment and all 6 operational catchments are also highlighted below in Figure 1. 

Metal mining in the Eden and Esk management catchment 

There is evidence of mining as early as the 11th century in the Eden and Esk catchment. The industry continued to grow throughout the 17th and 18th centuries, until the 19th century, when mining activity was at its peak. The last mine in the area (Silverband Mine) closed in the 1960s. 

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 Eden and Esk 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 from Figure 1, most of the historical mining activities in the Eden and Esk management catchment were concentrated in the Caldew, Eamont and Upper Eden operational catchments. 

Figure 1. Map showing the abandoned metal mines, mineral veins and baseline river monitoring sites in the Eden and Esk management catchment 

© Environment Agency

The tables below list the catchments (surface water bodies) that are polluted by abandoned metal mines in the Eden and Esk management catchment. These tables highlight where there are known point sources (mine adits or mine drainage levels) and diffuse sources (mine wastes or spoil heaps) within the waterbody catchment. The Environment Agency is continuing to investigate point and diffuse sources within the Eden and Esk management catchment by undertaking a series of catchment characterisation studies. These studies will help us identify which sources of metals need to be tackled to achieve the long-term statutory target. 

Caldew 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 Caldew operational catchment. 

Table 1. Summary of metal pollution sources in the Caldew operational catchment 

Catchment (Surface water body)	Point sources of pollution	Diffuse sources of pollution
Whelpo (Cald) Beck	Further investigation required	Further investigation required
Caldew (Hesket Newmarket)	Further investigation required	Further investigation required
Caldew (Upper)	Further investigation required	Further investigation required

Eamont operational catchment: sources of metal pollution 

Table 2 summarises which type of pollution sources from abandoned metal mines have been identified within the catchments (surface water bodies) in the Eamont operational catchment. 

Table 2. Summary of metal pollution sources in the Eamont operational catchment 

Catchment (Surface water body)	Point sources of pollution	Diffuse sources of pollution
Glenridding Beck	Yes	Yes

Upper Eden operational catchment: sources of metal pollution 

Table 3 summarises which type of pollution sources from abandoned metal mines have been identified within the catchments (surface water bodies) in the Upper Eden operational catchment. 

Table 3. Summary of metal pollution sources in the Upper Eden operational catchment 

Catchment (Surface water body)	Point sources of pollution	Diffuse sources of pollution
Crowdundle Beck	Further investigation required	Further investigation required
Stank Beck	Further investigation required	Further investigation required
Milburn Beck	Further investigation required	Further investigation required
Mill Beck (Dufton)	Further investigation required	Further investigation required

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 Eden and Esk management catchment, water quality monitoring was undertaken in 3 out of the 6 operational catchments (Caldew, Eamont and the Upper Eden). 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, 22 monitoring sites were selected across the Eden and Esk 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. In addition to these sites, another 47 sites were individually sampled to provide additional supporting data. 

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. No new remediation measures have been constructed in the Eden and Esk management catchment since 2022. 

Water quality monitoring results 

In the Eden and Esk management catchment, the target substances measured were arsenic, cadmium, copper, lead, nickel and zinc. 

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 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: Eden and Esk management catchment 

Our detailed monitoring across a range of flow conditions between January 2022 and March 2024 shows that in the Eden and Esk management catchment, the baseline length of polluted rivers for the abandoned metal mines target is 59km. 

Figure 2 shows the rivers in the Eden and Esk 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 Eden and Esk management catchment is 59km

© Environment Agency

Table 4 shows the river length (in km) that are polluted by each of the target substances within the Eden and Esk management catchment. In general, the most polluted rivers are impacted by more than one target substance. 

Table 4. River length (in km) polluted by each of the target substances within the Eden and Esk 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)	30	19	0	11
Lead (Pb)	24	19	0	5
Nickel (Ni)	0	0	0	0
Zinc (Zn)	53	29	7	17
Copper (Cu)	0	0	0	0
Arsenic (As)	2	2	0	0

Rivers polluted by abandoned metal mines: Eden and Esk management catchment 

Caldew operational catchment: baseline polluted rivers 

All tributaries of the River Caldew that were sampled as part of this work are polluted by one or more of the target substances. However, the main River Caldew is not polluted by any of the target substances. This is due to dilution by tributaries containing low concentrations of the target substances. Arsenic was included here because of the geology of the area and the abundance of arsenic bearing minerals found in the area. 

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 Caldew operational catchment is 31km

© 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. 

Eamont operational catchment: baseline polluted rivers 

Glenridding Beck is polluted along its length from the confluence with Swart Beck down to Ullswater. 

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 Eamont catchment is 4km 

© Environment Agency

Eden Upper operational catchment: baseline polluted rivers 

There are several streams polluted by the target substances in the Eden Upper operational catchment namely tributaries of the River Eden including, Crowdundle Beck, Stank Beck and Milburn Beck. 

Figure 5 shows the baseline polluted rivers in this operational catchment. 

Figure 5. The baseline length of rivers polluted by target substances from abandoned metal mines in the Eden Upper catchment is 24km

© Environment Agency