Stormwater project meets first major challenge

Water quality has finally shown some signs of improvement off Brighton's beaches, following the completion of what is claimed to be Europe's largest stormwater storage tunnel by Southern Water. Peter Minting reports.

Southern Water's giant stormwater storage tunnel at Brighton and Hove has been hailed as a success by the Environment Agency. Richard Hammond, environmental planning officer with the EA told WWT: "We would have expected serious pollution problems with the old system this summer. Instead, Hove beach met guideline standards under the EC Bathing Water Directive and Brighton beach stayed within the mandatory limits." The tunnel, designed by Hyder Consulting, took the contractors five years to complete and at a price of over £40 million dramatically exceeded the original estimate of £30 million. It is now said to be performing a valuable function.

Four primary dropshafts, along with a number of smaller shafts, now take the storm overflow from Victorian interceptor sewers at Hove Street, Medina Terrace, Norfolk Street and Grand Junction Road. Previously, this waste poured straight into the sea, causing a serious pollution hazard along a built-up area of coast popular with bathers.

Mr Hammond of the EA said: "Up until now, Southwick beach in Shoreham, west of Brighton, has failed bathing water quality standards every year." Up to 132,000m3 of overflowing waste water from the town¹s sewers and drains can be stored in the tunnel during heavy rain.

Once the storm waters subside, the wastewater is pumped from the eastern end of the tunnel at Black Rock to Portabello sewage treatment works. Here it is subjected to primary screening for sewage before discharge to sea.

However, there is still plenty of room for improvement, according to Mr Hammond: "The long sea outfall does offer some protection, but secondary treatment would make the system much more robust." He pointed out that although EA samples taken on a weekly basis show water to be safe inside the 200m zone, water further out could conceivably still be of a lower standard."

Taking this and other results into account, local pressure groups are continuing to fight for secondary treatment. Surfers Against Sewage (SAS) director Andrew Coleman said: "Despite the tunnel, tests carried out by Brighton and Hove Council, which carries out monitoring independently from the EA, show that water quality failed microbiological standards on several occasions this year."

Southern Water blamed four positive results for faecal coliforms in the summer of 1998 on rogue builders connecting sewer pipes to surface drains, which pour directly onto the beach.

In Southern Water's defence, spokesman Graham Amy said: "It is inevitable that other sources of pollution will become apparent after the building of such a large project. If we find out who is responsible for this leak, we will certainly be asking the council to take action."

Commenting on the Council's results, Mr Hammond of the EA spoke out in support of the utility: "We are designated as the only competent authority to assess beach standards. Having more than one monitoring scheme can cause unnecessary confusion. On the whole, we are pleased with the progress Southern Water is making in the area."

He added "Under the EC Water Directive, secondary treatment facilities should be installed for all coastal discharges by the year 2000."

To get approval for a secondary treatment stage at Portabello STW, Southern Water will still need to convince Sussex County Council that the development will not damage the surrounding Area of Outstanding Natural Beauty (AONB).

The Council has already rejected Southern Water¹s first proposals for a new treatment platform back in July. Reasons given included the large scale of the installation, which the County Council said Œcould affect the local geology' and Œcontribute to the problem of heavy traffic' in the Telscombe Cliffs area.

Mike Elrick, of Southern Water's technology group, said: "We are planning to appeal against this decision. If the appeal is not successful by January 1999, we will be forced to consider siting the installation elsewhere."

For the moment, Mr Coleman of SAS remains unimpressed with Southern Water's efforts: "I would be extremely surprised if Southern Water got their application through on time to meet the 2000 deadline, as the tunnel itself was over three years late."

Mr Hammond said that discharge consent procedures were, at least, well under way: "Southern Water's application has just arrived on my desk. I am now in a position to issue a licence with the requirement for secondary treatment."

However, he admitted that this alone would not be enough to guarantee secondary treatment by the year 2000. "If its planning applications are repeatedly turned down, Southern will be entitled to apply for a special derogation under Section 8.1 of the UWWTD (1991), to delay the installation of secondary treatment further."


Bathing water quality | planning


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