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Beach development causing a stink

https://www.iol.co.za/news/beach-development-causing-a-stink-1406099

Written by John Yeld

Cape Town – The environmental chickens are coming home to roost at Big Bay, Cape Town, where extensive development approved in highly controversial circumstances a decade ago has resulted in negative impacts that include major causes of concern for human health.

Such impacts have included a persistent sewage pipe leak into the lower car park basement of the Eden on the Bay development in the heart of Big Bay, the illegal pumping of leaked sewage water into the stormwater system, the poor management of the detention pond just to the north of Eden on the Bay that is “hazardous to human health”, and the design and use of another stormwater detention pond further to the north that constitutes a “potential hazard to beach users”.

And although the “wet beach” at Big Bay and associated algal growth is not currently a health risk, it has a negative aesthetic impact that is likely to persist unless the city upgrades the irrigation system on the frontal coastal dunes and manages it effectively.

This is according to a report commissioned by the City of Cape Town – “An investigation into adverse environmental conditions at Big Bay beach related to water seepage”.

Although completed and submitted to the sports, amenities and recreation branch a year ago, it has not yet gone to council or any committees, although mayoral committee member for community service Tandeka Gqada and the ward councillor have read it.

The report, by environmental geohydrologist Ritchie Morris and freshwater ecologist Liz Day, recommended that the sewer near the lifesavers’ clubhouse be redesigned and systems put in place to prevent sewage overflows during breakdowns of the controlling pump system.

It also recommended that a series of at least eight wells be installed over several hundred metres in a line inland perpendicular to the beach to monitor the flow and quality of ground-water.

The issue of the “wet beach” and severely reduced dry sandy area, combined with the appearance of an algal bloom on the wet sand, were among the reasons for Big Bay losing its Blue Flag environmental beach status in 2010.

In March last year, close to 300 residents turned out to protest about continuing sewage spills.

The consultants’ preliminary assessment in May last year found that the primary cause and source of the water flow causing the wet beach was the “excessive” watering of the lawns, flowerbeds and artificially vegetated fore dunes with an irrigation system in “disrepair”.

This was compounded by storm-water and wash-water being directed from Eden on the Bay down the walkways onto the beach, and run-off from the washing of surfboards and surfskis at the lifesavers’ clubhouse.

The assessment also found evidence suggesting that the sewerage system was leaking, and it concluded: “Fundamental to the overall situation is that a large development has occurred too close to a dynamic beach environment with inappropriate artificial engineering, and, consequently, a multitude of services and interventions are needed to maintain an unnatural situation.”

In their final report in October, the consultants stated: “Development of the Big Bay area, specifically at Eden on the Bay and the neighbouring residential erven to the south of this, has resulted in artificial changes to the beach zone, specifically the fore-dunes.”

The report noted that while beach seepage water was not clearly associated with sewage contamination, the results of water samples taken from a “sub-drain collector sump” in the Eden on the Bay basement car park suggested that the source of this leak was “almost certainly” sewage.

 “And, on the basis of the fact that it was leaking on every visit paid by the present study team to the basement car park, leakage is assumed to be an ongoing issue… For solids to be present suggests a fairly substantial leak or breach of the sewerage system…

“The fact that sewage is collecting in the basement sump… suggests that there may be serious leak problems with the sewage network associated with Eden on the Bay.”

This issue had to be addressed as a matter of urgency.

At the time, the basement leaks were being pumped into the adjacent stormwater system, which in turn discharged into a stormwater detention pond about 900m to the north, the report noted.

Seepage from this detention pond into the sea was “at present probably not a threat to beach users”, but future changes to the beach level or an increased discharge into the stormwater facility “would potential expose beachgoers to higher levels of bacteriological and other contamination”.

“Notwithstanding, the discharge of water of this quality to stormwater would be in contravention of the municipal bylaws.”

It recommended that the pumping of leaked sewage water into the stormwater system be halted immediately.

The report also recommended a system of groundwater monitoring wells both close to Eden on the Bay and up-gradient from it.

“Leaking sewers to groundwater and the sub-base drainage system below the basement car-parks of Eden on the Bay are of major causes for concern as not only is this a source of bacteriological contamination, but it is an additional recharge to the water-table. Unless addressed, the long-term consequences could be more severe.”

Signage noting the potentially hazardous nature of the retention pond just north of Eden on the Bay should be erected.

The report also noted that the irrigation system for the lawned area in front of the development had been leaking on each of four site visits, and said a review and upgrade of the entire irrigation system and its operation was required.

The report concluded: “The Eden on the Bay development should not be seen as the sole cause of the wet beach conditions at Big bay, although it is a primary contributor…

“In short, a coastal set-back for any development is a necessity, the width of which is driven by the physical appearance of that beach area and the forces at play. Unfortunately this was not applied at Big Bay and the de facto situation is going to be difficult to overcome.”

l The management of Eden on the Bay has been asked to comment. – Cape Argus