No further fish reports. 

Another excellent summary by WSA member Gordon Green showing the disgraceful sewage operation by Welsh Water

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Introduction

It is inevitable that wastewater from human activities goes into our rivers and coastal areas. Where

else would we put it? The questions rather centre around how pure we make the wastewater first.

Surely from a river point of view, it needs as a minimum to be consistent with our aspiration for

‘good’ ecological status under Water Framework Directive rules, meaning minimal impact from

human activities. One could even take this further and establish bathing water status. Our sewage

treatments works are in principle capable of delivering either of these outcomes. We have the

technology. However, when CSOs discharge, all this good work goes out of the window and we

discharge untreated wastewater directly to the river.

This report looks specifically at the subset of 2020 Combined Storm Overflow (CSO) discharge events

which are located within the Wye Catchment and which discharge to the river. The whole of the

Wye Catchment has sewage services provided by Welsh Water (WW)1, which simplifies things to a

degree. I have taken my data from the WW website [1], where it is made available (albeit not in a

particularly user-friendly form). I have then cross-referenced against the national dataset published

by the Rivers Trust [2].

The benefit of cross referencing the WW data with the 2019 RT data is that it allows us to link a

unique reference number (the EA/NRA permit number) to most named CSOs. There is obviously no

consistent naming convention for CSOs within the water industry, so it can get a little confusing

otherwise.

Furthermore, using data from the European Commission Urban Waste Water website2 [3], I have

established the input load of the corresponding Sewage Treatment Works (STW) in each settlement.

For small settlements not listed on this website, I’ve used the 2011 population figures. The purpose

of this data is to allow an estimate of the volume of untreated sewage coming from each specific

CSO, based on the size of population served.

In the 2019 dataset, a substantial proportion of CSOs were not monitored. Under pressure from the

industry regulator OFWAT, this has been substantially rectified for 2020. So, beware of simple

comparisons of the headline numbers. There are many more CSOs included in 2020. So, it is

necessary to compare the two years for specific CSOs to draw meaningful conclusions on trends.

Sewage infrastructure

Combined Sewers

A lot of our existing sewers date from the Victorian era. The Victorian practice was to run domestic

sewage (foul water) into the same sewer system as rainwater captured on rooves and paved areas

(stormwater). This is called a combined sewer. The weakness with this approach is clearly that the

flow volume increases massively when it rains – which would potentially overload the pipework as

well as the Sewage Treatment Works (STW) downstream. To the Victorians, who were never big on

pollution control, this wasn’t a problem – they just dumped the excess volume straight into the river.

1 Welsh Water is unique among UK water companies in that it wholly owned by a not-for-profit company

(limited by guarantee); there are no shareholders taking profit, but it still must operate without making a loss.

So, the usual financial drivers are still present, all be it without the need to pay dividends.

2 It appears impossible to find comprehensive open data on STWs from UK sources, whether that be from

government, from environmental regulators, or from water companies. The only drawback with the EC data is

that it was last updated in 2016. However, the input load data used here is unlikely to have changed much.

16-Mar-21 Page 4 of 12

Since the middle of the 20th century, we’ve been tending to separate these two flows. A modern

building will have completely separate foul water drains and stormwater drains. The foul water

sewer goes to the STW and the stormwater drain goes untreated into the local watercourse, albeit

often via a balancing pond to damp down the peak flows. The problem is that we still have lots of

combined sewers in our towns and cities. Moreover, there has been precious little done to deal with

this legacy problem over the thirty-some years since privatisation.

At the time of privatisation, in order to make the industry more attractive to investors, as if a

monopoly business wasn’t attractive enough, the companies were given an exemption against legal

liability arising from discharges from pre-existing CSOs. These are known as permissive licenses and

the EA can do little to challenge them. This at the time was intended to be a temporary

arrangement, but sadly it was never tidied up by Government (of any hue). Fish Legal had a good

push at this a few years ago but got nowhere. These CSOs can nevertheless only be legally used in

exceptional circumstances.

Incidentally, CSOs constructed since then are not permissive and the EA can exercise a higher level of

control. But I don’t think there are many of these.

There are actually two types of overflows in combined sewer systems: combined storm overflows

and sanitary sewer overflows.

Combined Storm Overflow (CSO)

CSOs are safety valves on specific sections of sewer. Their purpose is to protect that section of sewer

from overload, which could otherwise result in sewage backing up into houses. So, for example

Builth Wells has four CSOs, protecting different parts of the town. Sections of sewer are often

protected by buffer tanks which are ideally large enough to avoid the need to vent the CSO, other

than in exceptional conditions. In theory.

Also within this category are sewage pumping stations (SPS). These are frequently equipped with an

overflow, which works just like a CSO.

When a CSO discharges, the output of that section of the sewer system is flowing untreated directly

into the relevant watercourse.

Sanitary Sewer Overflow (SSO)

SSOs are similar but protect the STW from overload. They are generally co-located with an STW and

are also supposedly protected by adequate buffer tanks. They also should only vent in exceptional

circumstances.

When an SSO discharges, the entire input flow to the STW is flowing untreated directly into the

relevant watercourse.

16-Mar-21 Page 5 of 12

Approach

STW input load

In order to interpret the impact of CSO/SSO discharges, it is necessary to know the number of people

served by that section of sewer. The basis for this is the input load of the local STW or, if not

available, the town population.

Within the industry, STW loads are measured in PE (population equivalent). This reflects the

diversity of input steams served by the STW. As well as resident population, there are local places of

employment, transient tourist numbers and even some industrial effluent to deal with. For small

towns, the PE input of the local STW is generally a close match to the size of resident population.

Whereas for a large place like Hereford, the two STWs deal with a substantially higher PE input

(137k) than would be suggested by the population (60k).

PE

One PE (EU/UK standard) corresponds to a standardised set of biochemical quantities as follows:

Liquid 180 litres/day

BOD3 60gO2/day

Nitrogen 12gN/day

Phosphate 2.5gP/day

In the context of CSO discharges, and to ground this exercise in the everyday world, we could

usefully add a couple of additional lines:

Faeces 250g/day

Turds 5/day

CSO/SSO discharge output

In the results which follow, I have taken the above PE definition and multiplied it by the applicable

PE value.

 For SSO discharges, the applicable PE is the stated input load for the associated SWT.

 For CSO discharges, the applicable PE is the SWT input load divided by the number of CSOs

in the settlement.

So, if a town has an STW with an input load of 10,000 PE and has 4 CSOs, then an SSO discharge

would use PE = 10,000 and a CSO discharge would use PE = 2,500.

For sure, this approach is making some assumptions, but I think they are not unrealistic ones. In the

absence of more detailed disclosure by the water industry, it’s the only reasonable way to proceed.

3 Biochemical Oxygen Demand (BOD) is a measure of the organic matter carried in a river or waste stream; it is

measured as the amount of dissolved oxygen required by aerobic microorganisms to break down the organic

matter at 20°C, over 5 days.

16-Mar-21 Page 6 of 12

Results

Top level stats

Overall totals for the Wye catchment are as follow:

2019 2020

CSO/SSO discharges (#) 2,457 3865

Total duration (hours) 15,750 31,249

Table 1: overall CSO discharge statistics for entire Wye catchment

That’s an awful lot of exceptional circumstances. But to find out if this represents a real increase, we

need to dig down a little deeper. As I pointed out earlier, there are a lot more monitored CSOs in

2020.

Population centres

There are around 50 population centres within the Wye catchment which are large enough to have

an STW. These cover a total population of 144,000 people or so. However, it’s clear that the larger

towns and cities are going to be the main drivers of sewage pollution. Rather than look at statistics

for all of them, if we focus in on places with over 2,000 people, we have 10 settlements

encompassing 111,000 people – so most of it.

Comparing 2019 and 2020

The 11 largest settlements are listed as follows, in descending order of population:

Table 2: CSO/SSO discharge statistics for the larger settlements (2020 data excludes CSO/SSOs which

were not also monitored in 2019 – to allow direct comparison)

In this table, we are comparing apples with apples. Only CSOs listed in 2019 are included in the 2020

stats. So, the changes represent changes on the same specific CSOs in each settlement. The overall

average change across these 10 largest settlements is an increase in discharge duration of +239%.

Now, please explain that in terms of population growth or climate change! Because this is the excuse

proffered by the water industry.

If we now look at what this means in terms of sewage. Across the entire catchment, in 2020:

 Welsh Water dumped an estimated 1,184 tonnes of human faeces into the Wye and its

tributaries.

 This would equate to approximately 24 million turds.

2019 2020 Change

Settlement Pop’n Discharges Duration (hr) Discharges Duration (hr) %

Hereford 60,000 216 797 266 1,304 +64%

Leominster 12,000 97 494 66 358 -28%

Ross-on-Wye 10,600 216 707 256 987 +40%

Monmouth 10,500 95 885 86 1,163 +31%

Llandrindod Wells 5,300 339 2,553 256 1,405 -45%

Presteign 2,700 20 118 83 982 +732%

Kington 2,600 76 150 119 327 +118%

Builth Wells 2,500 97 493 250 2,212 +349%

Lydbrook 2,200 38 45 40 201 +347%

Rhayader 2,100 18 98 86 660 +573%

16-Mar-21 Page 7 of 12

Impacts of some specific overflows

Rather than attempting to present the whole dataset at the next level of detail, I will drill down into

a smaller number of representative settlements. I will present specific data for:

 Hereford – being the largest settlement within the catchment, with a population of 60,000.

 Ross-on-Wye – being an example in a medium settlement, of population 10,000.

 Builth Wells – being an example of the smaller settlements, population 2,500.

 Talgarth – which didn’t make the top ten, but sits on one of the smaller Wye tributaries, the

Llynfi; it has a population of 1,700.

Hereford

Hereford sits on the river Wye, immediately upstream of the Lugg confluence. The river here is large;

average flowrate on the main stem is around 50m3/s, with approximately 10m2/s joining from the

Lugg.

Hereford is served by two STWs: Eign and Rotherwas situated on opposite sides of the river, at the

downstream end of the city. The input loads are: Eign – 55,000 PE and Rotherwas – 82,000 PE. That’s

137,000 PE in total, substantially more than the resident population, reflecting the economic activity

in the city.

There are 15 CSOs within the city, 11 discharging directly or indirectly into the Wye and 4 discharging

into the Lugg. Eign has a named SSO, but I’ve been unable to identify an SSO for Rotherwas.

Discharge statistics for Hereford in 2020 are as follows:

CSO/SSO Discharges

(#)

Duration

(hours)

PE Faeces

(turds/hr)

Faeces

(kg/hr)

Tot.Faeces

(tonnes)

Wye

Barton Road 2 50 9,000 1,904 95 4.8

B. Greyfriars Bridge 72 288 9,000 1,904 95 27.4

Braemar Gardens 12 31 9,000 1,904 95 3.0

Eign STW SSO 82 1004 55,000 11,425 571 573.5

Eign 1B CSO 12 56 9,000 1,904 95 5.4

Grandstand Road 55 122 9,000 1,904 95 12.5

Belmont Roundabout 12 89 9,000 1,904 95 8.5

St. Martins Allotments 41 163 9,000 1,904 95 15.5

Whitecross Road 4 2 9,000 1,904 95 0.2

Three Elms Road 14 5 9,000 1,904 95 0.5

Herford Three Elms 3 4 9,000 1,904 95 0.4

Miss Chaves 18 5 9,000 1,904 95 0.4

Lugg

New Ct Lugwardine SPS 50 528 9,000 1,904 95 50.0

Trahern Place 0 0 9,000 1,904 95 0.0

Seaton Avenue 1 0 9,000 1,904 95 0.0

Lugwardine SPS No2 0 0 9,000 1,904 95 0.0

Table 3: CSO/SSO discharge statistics and resulting faecal loads for the Wye and Lugg at Hereford

First let’s look at some totals. Throughout 2020, the Hereford sewage system:

 Discharged 381 times, for a total of 2348 hours (or 98 days).

 Dumped an estimated 700 tonnes of human faeces into the river untreated (60% of the

catchment total) - approximately 14 million turds.

16-Mar-21 Page 8 of 12

Of particular note is the Eign STW SSO which discharged 82 times, for a total of 1004 hours. That’s

the equivalent of 6 weeks, 24x7. The average duration of each discharge event is 21 hours.

This is clearly not dictated by exceptional circumstances. Hereford did not have exceptional rainfall

on 82 days in 2020. This overflow is clearly opening on a regular basis for operational reasons.

Furthermore, the same can be said for several of the remaining CSOs. In other words, it’s cheaper to

dump it than to process it. It is sad to think that we do this in the UK in 2021, but I cannot see any

other explanation for these numbers.

Some final statistics on Hereford. For the duration of a discharge from the Eign STW SSO alone:

 We have over half a tonne per hour of disintegrating human faeces passing along the river

downstream of Hereford, with associated tissues.

 Plus, food waste, cooking fat and grease.

 Plus, all the non-degradable detritus which goes with it (wet wipes, condoms & the like).

 Plus, household detergents and other domestic chemicals, including bleaches and

disinfectants.

 Plus, miscellaneous pharmaceuticals and human hormones.

 The additional phosphate load will raise the river concentration by around 0.03mgP/litre4.

 The organic material will raise BOD by 0.8mgO2/litre; this will depress the river O2 level.

Ross-on Wye

The town of Ross-on-Wye lies approximately 30 miles downstream of Hereford. There are no major

tributaries en route, so average flowrate is approximately the sum of the Wye and Lugg at Hereford

– around 60 m3/s.

There is one STW serving Ross, Lower Cleeve, located at the downstream edge of the town and

having an input load of 18,000 PE – quite a bit more than the resident population of 11,000. Ross

also has six CSOs within the town, all discharging into the river Wye.

Discharge statistics for Ross-on-Wye in 2020 are as follow:

CSO/SSO Discharges

(#)

Duration

(hours)

PE Faeces

(turds/hr)

Faeces

(kg/hr)

Tot.Faeces

(tonnes)

Cawdor Arch 1 0 2,594 540 27 0.0

Homs Road 88 366 2,594 540 27 9.9

Hope and Anchor 97 593 2,594 540 27 16.0

Weir End 9 20 2,594 540 27 0.5

Lower Cleeve STW SSO 69 193 18,175 3,780 189 36.6

Brampton Street 79 179 2,594 540 27 4.8

Station Street 2 1 2,594 540 27 0.0

Table 4: CSO/SSO discharge statistics and resulting faecal loads for the Wye at Ross-on-Wye

Again, let’s look at some totals. Throughout 2020, the Ross-on-Wye sewage system:

 Discharged 345 times, for a total of 1352 hours (or 56 days).

 Dumped an estimated 68 tonnes of human faeces into the river untreated

(approximately 1.4 million turds).

4 Both Hereford STWs are equipped with phosphate reduction systems, which are obviously bypassed by an

overflow discharge.

16-Mar-21 Page 9 of 12

As for Hereford, we see four of the seven overflows discharging a huge number of times. Again, we

see that one of these is the sewage treatment works SSO, dumping the entire, untreated sewage

load of Ross into the river.

That’s an estimated faeces flowrate of 189kg/hour or 3,783 turds per hour.

Once again, we cannot remotely justify this in terms of exceptional circumstances. These are

operational decisions. On top of the 700 tonnes of grey sludge trundling down the riverbed from

Hereford, Dwr Cymru Welsh Water have decided to add a further 68 tonnes at Ross, to freshen it up

for the tourist at Lydbrook and Symonds Yat further downstream.

Builth Wells

Upstream now, to Builth Wells, also on the main stem of the Wye, 50 miles or above Hereford.

Builth is located at the confluence with the river Irfon. The flowrate here is around 35m3/s.

Builth is served by a single STW, having an input load of 4,229 PE. In addition to the STW’s SSO, there

are 4 CSOs around the town. All discharge into the Wye.

Discharge statistics for Builth Wells in 2020 are as follow:

CSO/SSO Discharges

(#)

Duration

(hours)

PE Faeces

(turds/hr)

Faeces

(kg/hr)

Tot.Faeces

(tonnes)

Builth Wells STW SSO 122 1,483 4,229 881 44 65.3

North road 13 23 1,057 220 11 0.3

The Strand 76 282 1,057 220 11 3.1

Station Road 4 32 1,057 220 11 0.4

Scout Hut, School Br. 35 393 1,057 220 11 4.3

Table 5: CSO/SSO discharge statistics and resulting faecal loads for the Wye at Builth Wells

The totals for Builth Wells, throughout 2020 are:

 Discharged 250 times, for a total of 2,213 hours (or 92 days).

 Dumped an estimated 73 tonnes of human faeces into the river untreated

(approximately 1.4 million turds).

This small town has dumped more raw sewage into the Wye than Ross, which is over four times the

size. Once again, the main offender is the STW SSO. This has discharged on average once every three

days for a duration of 12 hours. Two of the CSOs also have inexcusable discharge frequencies.

Relative to the smaller river up here, this pollution is twice as severe as the problem at Ross.

The estimated faeces flowrate for the Builth Wells STW SSO during a discharge is 44 kg per hour, or

880 turds per hour.

Talgarth

Talgarth is a small town located a few miles from Hay-on-Wye. The local STW serves Talgarth (pop.

1700) and the nearby village of Bronllys (pop. 900); it has an input load of 2,970 PE. The significance

of this settlement is that it sits on a small tributary of the Wye called the Llynfi, into which the STW

discharges. The Llynfi has an average flowrate of 2.3m3/s, meaning that any sewage pollution is

much more significant because dilution is around one twentieth of that on the main stem of the

Wye. There are three CSOs in Talgarth, two in the town and one up the road in Bronllys.

Discharge statistics for Talgarth and Bronllys in 2020 are as follow:

16-Mar-21 Page 10 of 12

CSO/SSO Discharges

(#)

Duration

(hours)

PE Faeces

(turds/hr)

Faeces

(kg/hr)

Tot.Faeces

(tonnes)

Bronllys 68 297 990 206 10 3.1

Bronllys Rd (STW SSO) 12 12 2,970 619 30 0.4

A497 Bronllys Road 1 1 990 206 10 0.2

Talgarth 0 0 990 206 10 0

Table 5: CSO/SSO discharge statistics and resulting faecal loads for the Llynfi at Talgarth

The totals for Talgarth and Bronllys, throughout 2020 are:

 Discharged 81 times, for a total of 310 hours (or 13 days).

 Dumped an estimated 3.7 tonnes of human faeces into the river untreated

(approximately 74 thousand turds).

The main offender here is the Bronllys CSO. Over the year, it has discharged over 3 tonnes of faeces.

There is clearly a capacity problem here that needs fixing. Just to put this into context, imagine you

are standing in the Llynfi with a fly rod. The river is perhaps eight metres wide and the water is up to

your knees. Through the clear water, you can clearly see the gravel at your feet and across much of

the river. The Bronllys CSO opens, the river turns an ugly grey colour, the trout stop rising and you

watch human turds drifting down the river – one every fifteen seconds or so. (If the SSO opens, it’s

one every five seconds. But thankfully the SSO hasn’t opened anything like as often this year). A truly

delightful, early end to your days fishing.

Before we leave Talgarth and the river Llynfi, another calculation we can do concerns phosphate.

The STW here is too small to have required phosphate reduction within the 2015-20 OFWAT review

cycle, so the entire sewage phosphate load flows into the river all of the time, irrespective of any

CSO activity. Based on average flowrate for the river and the standard PE definition, we would

expect a total phosphate concentration of around 0.04mgP/litre. Well above the WFD ‘good’

classification, even before agriculture gets to contribute.

Summary

I have presented details of four settlements based on objective selection criteria, specifically not

because they are particularly bad in some way. They are in fact typical of the wider dataset and

serve to illustrate the nature and severity of the problem.

I have expressed the results in terms of tonnes of faeces and turds per hour in a deliberate attempt

to ground things in the everyday. For most people, technical terms like BOD mean little and are not

informative.

I will end this section with some visual observations by friends who spend time by the river Wye.

Maybe not quite so objective, but very relevant – and true.

 I watched grey foam float down the river all day today (Mike O’Neil, below Hereford)

 I saw sanitary products drifting past today (Ed Green, below Hereford)

 It looks like the Hereford SSO is dumping every night; each morning we seem to get sewage

debris floating down the river (Ed Green, below Hereford)

 I looked down from the boat through clear water and could see grey sludge being carried

along the bed of the river (Trefor West, below Hereford)

 The gravel is covered in grey slime (Rob Leather, Ross-on-Wye)

All the above comments are fully consistent with the CSO/SSO discharge data presented, specifically

the Hereford and Ross-on-Wye statistics.

16-Mar-21 Page 11 of 12

Conclusion

 CSO/SSO discharges are occurring across the Wye catchment with horrendous frequency.

Such frequencies are not remotely consistent with the definition of exceptional

circumstances. The duration of discharges, on a like-for-like basis, has more than doubled

between 2019 and 2020. There is no plausible population growth or climate change

justification for this.

 The alternative explanation is that the published statistics are incorrect. Either way, it

doesn’t cast WW in a very good light. They are either wilfully polluting the river Wye, or they

are knowingly publishing partial statistics. They can’t have it both ways.

 If the Welsh Water statistics are to be believed, then these are deliberate, operational

discharges.

 Most such discharges are therefore illegal, but the EA, or NRW in Wales, do not prosecute.

So, this is yet another area where our environmental protection agencies are self-evidently

failing in their statutory duty to ‘reduce and prevent pollution’.

 The situation on Hereford is particularly egregious. I remain concerned that there is no data

for an SSO at the Rotherwas STW. There surely must be one. The alternative is that overflow

from Rotherwas is discharged from Eign (the two STWs being part of a linked agglomerate).

If this is the case, then my calculations are an under-estimate of the impact since Rotherwas

supports 50% more input load than Eign.

 The privatised water industry has owned this infrastructure now for over thirty years. There

are no longer any excuses for any inadequacies. This is what they took on at privatisation.

They own it – and they own the problem.

I spent my childhood in the industrial northwest of England. Major fish kills every couple of years,

resulting from STW discharges into the local streams were accepted as a fact of life. They were

however generally associated with heavy rainfall. I now live in Gloucestershire and fish the river Wye

on a regular basis. It is rather shocking, fifty years later, to find that Dwr Cymry Welsh Water

consider it acceptable to wilfully dump untreated sewage into one of the most precious rivers in the

UK. Things should be getting better, but our experience, our observations, and the data presented

here show beyond doubt that we are going backwards. The evident disdain for our shared, natural

environment is depressing.

It makes me so proud