Water quality is still poor

Our latest tests show that water quality is poor. This means that the water in the marine lake does not meet EU standards for bathing water quality.

The sample of water taken from Clevedon Marine Lake on June 10th showed that the water had higher levels of bacteria than is deemed safe for swimming. The community made a huge effort to empty and clean the lake following the last poor water quality test, but it did not solve the problem as hoped. It is likely that the water from the estuary that refilled the lake was also below standard.

You should not swim in the lake until it has been emptied and refreshed, especially if you have lowered immunity.

If you do swim, please wear goggles and earplugs to protect yourself, and wash your hands before eating.

Red flags around the lake show that swimming is not advised.

Marlens, the charity that looks after the lake will today be deciding on a course of action to refresh the lake once more. Small overtops are due on the 5th to 6th July, although these may not be enough to refill the lake. The next major overtop isn’t until July 21st to 24th.

About water quality

The water quality in the Severn Estuary, which refills the lake, is monitored by the Environment Agency from May to September, with samples taken from Clevedon Beach next to Clevedon Marine Lake. Poor water quality warnings for the estuary are issued online and often coincide with periods of heavy rain, causing run-off from the land. But, the Environment Agency is not currently testing as normal because of the Covid-19 pandemic.

The current tests show the levels of enterococci bacteria remain high compared to previous water samples.

Red flag shows poor water quality

Red flags at Clevedon Marine Lake show poor water quality

Severn – first, second or third?

In November 2016, the Bay of Fundy installed a tidal turbine that, in time, is designed to generate enough electricity for the whole of the Canadian Atlantic seaboard – as a first step toward a lower carbon future using the power of the highest tidal range in the world. The intervention raised an interesting question from Jon Tuttle: Does this mean the Bristol Channel now has now the highest tidal range in the world, moving up the ranks from second position? Sadly, the answer is no.

I did some investigating and received the following email reply from Todd Ehret, an oceanographer with the Center for Operational Oceanographic Products and Services:  I think what you are referring to is an “energy producing” object … something like a dam; but not nearly as restrictive — water still flows freely through a “barrage”. The existence of the barrage would not have a significant effect on the range of tides in the area. The Bay of Fundy is not going to lose its place as the largest range of tide, unless there is something built which all but completely blocks the entire bay. Such an energy barrage object would be installed in very small, narrow sections of the Bay of Fundy. On the “upstream side” of such a barrage, there **might be** small change in the tidal conditions, perhaps on the order of a few millimeters to 1 centimeter. But on the “downstream side” of the barrage, the range of tides would be unchanged, or might actually increase by a small amount (again on the mm to 1cm scale). That is part of the discussions and engineering of using tidal changes to create energy. Such constructions are intentionally designed to have limited impact on the “natural conditions” of area upstream of the construction.

Regards,
Todd Ehret

Oceanographer
User Services
Center for Operational Oceanographic Products and Services
Web: tidesandcurrents.noaa.gov

I have included two websites that back up this information. At this point in time, the Severn Estuary is recorded as third on the all-time list.
https://tidesandcurrents.noaa.gov/faq2.html
http://www.top-ten-10.com/science/geography/tidal-range.htm

Nevertheless, it is an invigorating and challenging stretch of water, never to be underestimated.  Without it, Clevedon Marine Lake just wouldn’t be the same. Happy swimming, paddling and sailing! 

Jo McCready-Fallon
October 2017