As we all know, 2020 was a year like no other, however, even with the Salford Watersports Centre closed, Salford City Council made the decision to continue the monitoring programme that APEM had put in place. This decision ensured that the excellent water quality achieved at the Quays remained for all to enjoy once we could get back in the water.

Without the monitoring programme there was a risk of conditions deteriorating and APEM are thrilled that now the Salford Watersports Centre is fully operational again, visitors are flocking to the Quays to enjoy the water environment that Salford City Council and APEM has created and work hard to maintain.

The remit of APEM’s work includes:

  • To provide management information for the efficient operation of the aeration system to maintain the aesthetic and environmental quality of the Quays Inner Basin water environment without unnecessary use of electricity.
  • To provide management information on compliance with the Bathing Water Directive and World Health Organisation guidelines to allow the safe pursuit of watersports.
  • To monitor the success of the management strategy with regard to the eventual attainment of ecological stability within the Quays.

Why is the water so blue?

Anyone visiting the Quays may wonder why the water is such a lovely shade of Mediterranean blue (this may be the closest many of us get to the Mediterranean this year!). Like most water bodies, the Inner Basins at Salford Quays experience an annual bloom of blue-green algae in late summer/early autumn. Public health concerns regarding blue-green algae centres on the ability of many species to produce toxins.

Blue-green algae in small numbers are a natural part of the water system and as long as the cells remain thinly dispersed throughout the water this does not necessarily imply a health hazard. It is the algae’s tendency to form dense surface scums of extremely high cell density when conditions are suitable which poses a threat as this leads to the accumulation of toxins at hazardous levels.

In 2014 the bloom in the Inner Basins at Salford Quays represented the largest recorded to date. Densities above the WHO guideline levels were recorded on numerous occasions. Visible surface scums were also reported.

A similarly persistent bloom occurred in 2015 and therefore APEM implemented a trial management solution with various options tested. Subsequently in 2016, and every year since, dosing of blue dye (Pond Blue) is undertaken in all the Inner Basins, consisting of an initial application in February followed by monthly top-ups through to November.

The dye is used to block out the available light for photosynthesis, which can suppress algal growth and limit the formation of blooms and scums. The base of the dye is an approved European Food colouring (the blue is E133) which is manufactured from organic sources.

It’s free of pesticides, herbicides, algaecides and other chemicals and considered to be non-toxic to humans, aquatic biota and any other wildlife or domestic animals. But don’t worry, swimmers don’t come out of the water blue – just members of the APEM team!

staff member with blue face holding wet wipes

blue-green algae

The data (below) show that in 2016 cell densities were markedly lower compared to the previous two years and remained low again in 2017. In 2018 densities increased in the autumn, but there were no flecks observed in the water column (picture above) and no scums formed and levels remained below the WHO boundary (20,000 cells/ml).

The increase in cells in 2018 most likely reflects the unprecedented weather experienced during 2018, where summer air temperatures were much higher than the previous three years and APEM recorded a significant increase in algal blooms at numerous locations throughout the UK in 2018.

Similarly in 2020, a bloom occurred in October, but below the WHO boundary, and as in 2018, may reflect the prolonged warm weather experienced in the spring and summer of that year.

graph

Figure 1 Blue-green algae cell densities in the Inner Basins in recent years

Bacteriology

As well as blue-green algae there is a risk to recreational users of water bodies from faecal pollution because of the presence of a number of pathogenic microorganisms, in particular where whole-body contact takes place (i.e. when there is a meaningful risk of swallowing water).

In the Quays, rainfall has been found to lead to relatively short periods of elevated faecal pollution as surface run-off increases. Higher levels are also reported in summer as a result of increased use of the water for recreational purposes and hence increased entry of faecal matter from defecation and/or shedding.

Elevated levels of faecal matter are also recorded at times when there is an increased presence of birds on the water, for example in July-August when swans are moulting and unable to fly.

To ensure a high factor of safety in recreational water bodies, common practice is to monitor a number of indicator organisms. The universal indicators are the coliforms. These bacteria are of faecal origin (human and animal). Faecal streptococci/intestinal enterococci are also used as an index of faecal pollution in recreational waters. This group contains species of two genera, Enterococcus and Streptococcus.

The Bathing Water Directive (BWD)

The main source of guidance for the safe pursuit of swim events in waterbodies is the guidance set out under the EC Bathing Water Directive (BWD). The main objectives of the BWD are to protect public health and the environment from faecal pollution at bathing water sites.

Although waters within the Inner Basins are not officially designated ‘bathing waters’, as defined under BWD, compliance against the thresholds identified in this legislation is a useful management tool to assess the quality of waters for recreational use at non-designated locations.

The BWD uses E. coli and intestinal enterococci as an index of faecal contamination to assess water quality. There are four classifications as follows:

  • Excellent – the highest cleanest sites likely to attract beach awards, such as Blue Flags
  • Good – better than the minimum standards hence generally good water quality
  • Sufficient – the water meets the minimum standards
  • Poor – the water has not met the minimum standards. Work will be needed to improve bathing waters not yet reaching the Sufficient category.

Assessment is based on a percentile evaluation. This evaluation is a calculation using the actual values for each parameter measured, as opposed to compliance of a number of samples. This is not applicable to one-off sampling and therefore samples from Salford Quays are assessed based on the limits stipulated on a sample-by-sample basis.

The team at APEM test the water throughout the Quays on a fortnightly basis to ensure it remains safe for recreational use.

The E. coli (Figure 2) and enterococci (Figure 3) data from 2020 indicates a high standard of water quality within the Inner Basins was maintained with most samples indicating an Excellent status (MSC is samples taken from the Ship Canal as a comparison).

graph

Figure 2 Percentage compliance with the EC Bathing Waters Directive (2006/7/EC) thresholds based on E.coli data in 2020

 

graph

Figure 3 Percentage compliance with the EC Bathing Waters Directive (2006/7/EC) thresholds based on Enterococci data in 2020

caddisfly

Caddisfly (Ceraclea senilis)

Benefits wider than watersports activity

The improvements in the Quays since the 1980s have also offered a huge benefit to aquatic fauna.

Macroinvertebrate and zooplankton diversity has steadily increased since the 1980s being indicative of a healthy water body. The taxa recorded include increasing numbers of pollution-sensitive taxa such as the caddisfly Ceraclea senilis, which is designated as ‘Nationally Notable’.

The continued presence of pollution-sensitive taxa indicates the long-term improved water quality and is also facilitated by improvements in habitat diversity through the establishment of natural macrophyte stands. The combination of these factors has provided a high-quality environment where aquatic fauna can flourish.

Peter Openshaw, Interim Strategic Director Place at Salford City Council, said:

“Salford Quays has been transformed into a vibrant mixed-use area and is considered to be one of the city’s finest assets. The Lowry, MediaCityUK, the Quayside outlet mall, Salford Watersports Centre and a range of other facilities make this a great place to both live, work and visit. The Ship Canal and Quays themselves are a key wildlife location and provide a range of activities for watersports enthusiasts. It’s very important that the water quality is maintained to the highest standard and working with APEM ensures that.”

APEM’s Associate Director, Heather Webb has managed the work at Salford Quays since 2008 and it has become her ‘baby’.

“I am delighted to continue to work with Salford City Council to manage the water environment at the Quays. The area is such a well-known and busy watersports facility and visited by people from all over the world thanks to the investment in infrastructure (The Lowry, MediaCity etc) so it remains vital that we ensure the excellent standards of water quality are maintained for all to enjoy. I am excited to see the watersports centre reopen after lockdown and for people to start visiting and enjoying the area again.”

 

Do you have a planned swim or watersport event? Are you confident that the quality of the water meets the standards as highlighted previously? Heather Webb and the APEM team are on hand to discuss any issues which may arise at your sites.

If you have any queries, please contact Heather Webb, Associate Director.
Alternatively you can email us here. Or call 0161 442 8938.