Four seasons on Warwick's River Avon: Autumn brings the Avon's beauty to life

This is the last of four articles describing the unique nature of the beautiful River Avon, written by the Warwick Boat club ‘Old Blades’.

Autumnal Avon. Photo by Gur Rotkop.
Autumnal Avon. Photo by Gur Rotkop.
Autumnal Avon. Photo by Gur Rotkop.

The River Avon is a very benign river, nearly always calm and is rarely a hazardous water for river users. It is untroubled by waves that the wind whips up on open waters or by treacherous currents. Its natural state is a picture of serenity!

The mirror finish on dead calm days is particularly beautiful in the autumn, reflecting the red and orange hues of the tree canopies above in a blissfully tranquil feast of colour.

This autumnal image is perhaps the essence of the Upper Avon that best defines its place as one of Britain’s prettiest rivers.

There are times though when the river can show a more menacing side of its character.

Heavy rains cause the river level to rise and there are occasions when flooding is not unknown, and the stream can be strong enough to deter even the most courageous water users.

If you stand on the bridges when the river is in full flood, you can observe the otherwise hidden route of the natural stream, made obvious by the narrow string of the flotsam carried down it.

The river management is controlled by the Environment Agency who use sluices in the weirs to ensure that the natural floodplains and river topography are deployed to calm the flow of water so that no one stretch gets too high at any one time. April 9/10 1998 saw an exception to this rule, with the most memorable flooding of this region leaving much of lower Leamington under water.

Whilst weather issues are clearly visible, there are less obvious hazards in the water itself.

Unlike rivers like the Wye, which has been in the news this year because of the highly visible ‘run off’ pollution from chicken farms and the like, the Upper Avon has benefitted from being part of a pilot to clean up the catchment waters feeding it.

Various projects are currently in hand to address phosphate run off from fields into the River Leam that feeds into the River Avon. Severn Trent funds an Agricultural Adviser post, employed by Warwickshire Wildlife Trust, who is working with landowners and farmers across Upper Avon and Leam catchments on some of these issues.

Old photos show traditional punters on the river. However, the original gravelly base of the river has now become covered in a thick layer of mud, the product of years of decaying weeds, the growth of which has been encouraged by fertiliser run-off and other sludge. Punting is no longer possible on the Avon.

However, the advance of the weeds does seem to have abated in the last few decades and fish have started to return. From only about four species in the river in the 1980s, the decline in heavy industry, improvements in land management and reduction in discharges (especially from the Finham Sewage works) have resulted in the quality of the catchment water steadily improving. As the water became clearer, more plant growth meant that more invertebrates and other fish food enabled a greater range of fish species to thrive. Now there are about 15 species.

The benefits of this improvement also apply to water birds, dragonflies and water life generally. Herons and kingfishers have been regularly observed and are presumed to be resident throughout the year. On one occasion, an early morning heron was seen

swallowing a large grass snake for breakfast. The increase in fish diversity has almost certainly been in part responsible for the more recent sightings of otters in our locality with some being ‘caught on camera’.

The Environment Agency’s study, published in 2021 (with data from 2019), now classifies this stretch of the Avon as ‘Moderate’ in terms of overall water quality, and highlights several areas of concern, including:

- Poor status for phosphate; sources stated as Urban, and Water Industry

- Fail status for Polybrominated diphenyl ethers (PBDE), no identified source

- Fail status for Mercury and Its Compounds, no identified source

- Fail status for Perfluorooctane sulphonate (PFOS), with Sector under investigation

- Moderate status for macrophytes (plants visible by eye, not microscopic).

All raw sewage contains Phosphorus, partly because of the high Phosphate content of most detergents and cleaning products. Only about 40 per cent is processed by bacteria in sewage treatment plants and the levels remain too high to discharge to sensitive waters.

For this reason, the maximum levels of Phosphorous in sewage treatment plant effluent are insisted upon by many planning authorities. While phosphates are low in toxicity, they instead cause excessive nutrient pollution, feeding the harmful algal bloom.

For many fish, a small amount of sewage pollution can be a positive thing, giving the water

plants the nutrients they need, and is the basis for the "circle of life" under water. With a little colour in the water, fish are protected from some predators.

Unfortunately, incidents of sewage pollution from planned or unplanned discards have apparently increased recently. As this paper recently reported, “More than 200 ‘sewage dumps’ took place in Leamington and Warwick rivers last year - a 67 per cent rise in cases”.

Monitoring is happening by the Environment Agency and the water authorities (Severn Trent currently have a water quality monitoring station on the bank in St Nicholas Park in Warwick). However, up to date water quality data is itself part of the problem and it is not always published or easily available to the public.

The eventual consequence of this increase is not yet clear, but given the increase in recreational use of the river by wild swimmers and paddle-boarders during the warm weather of this year, it is important that the situation is monitored and the potential risk to

public health understood and communicated.

Despite the challenges, the River Avon never ceases to be a place of interest and is a fantastic asset for us all where we can celebrate the beauty of the river, even as autumnal colours fade away.

The Environment Agency and Warwick District Council are both invested in maintaining the health of the River Avon and of its users. There have been some historic decisions of which they can be proud, such as not allowing the commercialisation of the river by developing it for navigation.

The challenge now is continuing the good work they have begun, by delivering the water improvements and supporting all the sports and recreational users who enjoy the Avon.