A brief history of Hastings’ sewers and future flood risks for the town centre
The following table is the current working draft of a timeline taking us from the earliest formal sewer works in Hastings up to the present day.
At the time of writing we are still waiting for a completed hydraulic analysis of the combined sewer system from Southern Water, however the current conclusions being presented with regards future flood risks are as follows:
CONCLUSIONS
‘The measurements and modeling show that now the Pelham outflow and associated tidal flap are repaired (and as long as there is no significant shingle blockage), in terms of surface water and the culverted stream the town centre has the capacity to discharge rainfall of the intensity seen in January and October 2023. Findings indicate that this would be the case even if the manhole in South Terrace was re-opened, and that had the outflow and tidal flap been clear and fully working in 2023 no flooding would have been experienced. There is, however, still the chance of a heavier rain incident (of the type seen every fifty years or so) which could potentially see surface water flooding in the same areas that were affected recently. Further work is being done to review the risks of basement sewer flooding to individual properties. An assessment now needs to be made as to whether work is required to hold back significant amounts of surface water, or, if uncontaminated, find ways of discharging streamwater or rainwater directly to the sea, rather than adding it to the combined sewer system.’
As agreed with Southern Water
Essentially the point being made is that if in January the pipe had not been under the shingle, and had the flap been operating in both January and October, then the manhole would not have surcharged.
TIMELINE
We welcome comments, amendments and additions if anyone has evidence of errors or key ommissions.
DATE | Problems, actions and notes |
pre-1857 | PROBLEM: Sewers feeding into natural watercourses causing contamination to drinking and washing water prior to sewage finally feeding direct to the sea. All of this causing ongoing health issues and flooding around the town centre area when high tides coincided with heavy rain |
ACTION: New sewer system created, with pipes and tunnels seperating sewage from clean water and leading to eight short outflows | |
1857 – 1860s | PROBLEM: Sea becoming increasingly popular with tourists but needed to be cleaned of raw sewage from outfalls. |
ACTION: Construction of west-to-east 6ft x 4ft tunnel taking sewage from town centre to Rock-a-Nor. Construction of 2-million litre holding tank so that sewage could be released at low tide through a single short outfall. Additional construction of further east-to-west tunnel to take St Leonards’ sewage to a single outfall at Bulverhythe | |
NOTE: Two emergency storm overflow outfalls retained and extended at Harold Place and Warrior Square | |
Late 1800s to 1937 | PROBLEM: Increased urban development puts additional pressure on the sewer system. This leads to the Rock-a-Nore holding tank becoming inundated and sewage backing up into the town centre, especially at high tides. The situation is made worse by high sea levels and storms adding seawater to sewage in the lower parts of the town. |
ACTION: The Old Roar Ghyl/Priory Stream watercourse which had once flowed naturally overground was gradually culverted from its mouth in the Harold Place area up to the point it exited Alexandra Park. The lower section of the culvert was integrated into the town’s combined sewer network with a connection at the junction of Queens Road and South Terrace, which then flowed as one to Harold Place. Reservoir management seems to have ended in 1901 when the attendant passed away, and it’s unclear when or why the park penstocks were removed. | |
1937-1939 | ACTION: The Priory Stream culvert was diverted from South Terrace to Carlisle Parade by Hastings Borough Council through a new section under Wellington Square and out of a dedicated beach outfall. This disconnected it from the town centre comnined sewers. A tidal non-return flap was put in place next to the road in front of the beach to prevent backflow at high tides. |
NOTE: Incidents of town centre flooding were significantly reduced in the post-war years, especially when the culvert/sewer works were combined with new sea defences to prevent coastal flood risks. Notably the culvert was cited as being used to irrigate the cricket pitch in dry weather, however the flooding it was linked with was clearly related to the fact that it fed into the combined sewer in Queens Road which led to overloading of the system and surcharging in Station Road, which is the lowest part of town. | |
1959-1960 | PROBLEM: Short outfalls continuing to pollute seas |
NOTE: Coombe Haven long (1.87 mile) outfall built to take treated sewage away from the shoreline. | |
1970s and 80s | PROBLEM: Surcharging sewers once again became an increasing problem due to large-scale housbuilding, with the resulting floods flowing back to the low-lying land that was used as a cricket pitch. |
NOTE: Records show floods over this period all emenating from sewer surcharges or surface water due to blocked drains. No notes or indications of the culverted stream being a factor. A contemporary account from a council workman who maintained the culvert confirms that it was never seen to surcharge in South Terrace through the original manhole on the corner of Queens Road. | |
Early 1980s | ACTION: Macerating plant built at Rock-a-Nor and all waste sewage pumped directly to the treatment works for all-tidal-stages long-sea disposal. |
1998-1999 | ACTION: A large storm tunnel was dug from Alexandra Park to Warrior Square, with a pumping station installed at Coombs to empty the tunnel’s contents and transfer it to the waste water treatment plant at Coomb Haven. This was designed to alleviate the town centre sewage flooding issues. |
NOTE: The tunnel had a ‘tributary’ feeding it from the Harold Place confluence of the town centre combined sewer system, which led to the decision to make the remaining Harold Place outfall redundant. At the same time Priory Meadow shoping centre was built, with a remodelled junction between South Terrace and Queens Road. It is believed the original manhole is the one now on the pavement outside M&S. Additionally, when the centre was built, pumps were installed to remove rainfall runoff and move this into the combined sewer system. | |
2000-2019 | PROBLEM: Other than three notable flood events that had specific and identified causes (all related to mechjnical pumping failures) no major floods were reported in the town centre area. |
ACTION: The events in question were all related to human error or mechanical failure in pumping systems. Lessons learnt from these incidents have seen systems made more resiliant and automation introduced. | |
NOTE: In both August 2014 and August 2015 Hastings experienced similar rainfall patterns to those that later hit the town in 2023. These saw 35-55mm of rain over 24 hours following long wet spells, and with peak downpours of 1.5 – 3mm per 15 mins. In neither of these cases was any town centre flooding noted. | |
December of 2017 | PROBLEM: A storm broke the Pelham beach outfall pipe, resulting in the chamber containing the tidal valve surcharging. |
NOTE: No flooding recorded in South Terrace | |
Unknown date in 2019 | PROBLEM: Water quality around the Carlisle Parade outfall was perceived as an issue |
ACTION: Southern Water created a new inspection manhole in South Terrace to access a point in the culvert where it was believed a build-up of detritus was affecting the water quality. | |
NOTE: At this time the ownership of the culvert was still in dispute between ESCC as the highways authority and Southern Water. | |
2021-2022 | PROBLEM: In June ’21 and Nov ’22 localised flooding was observed in South Terrace – seen to be emanating from both the new inspection manhole and through the road surface itself along the lowest section of the carriageway. |
NOTE: Over this period the terminating section of the outflow became buried under several meters of shingle and the debate between Southern Water and ESCC over ownership of the culvert continued, until, towards the end of 2022, the MD of SW agreed to adopt the pipework. | |
Early November 2022 | ACTION: November 2022 installation of two pumps at the tidal valve chamber with signage stating this was to protect the town centre from flooding. |
16/01/23 | PROBLEM: Flooding throughought the town centre with a combination of surcharging sewers in Station Road and property basements preceded by a large surcharge from the manhole in South Terrace which flowed through Priory Meadow. Seafront pumps inundated. |
ACTION: Clearance of shingle from the area around the outflow pipe | |
NOTE: Shingle clearance coincided with a rapid drop in floodwater levels in the town. | |
2023 (Jan to Sept) | ACTION: Pumps left in place until completion of remedial work to the outflow pipe to replace the broken section. Section 19 report prepared and published in October 2023. |
NOTE: Early draft of S10 report in May 2023 pointed to a potential issue with the new manhole in South Terrace – but did not fully explain the reason for the water backing up to that point. | |
20/10/23 | NOTE: Final s19 report published with a finding that shingle blocakge may have been partly to blame, but also that water from the surcharging manhole in South Terrace had overwhelmed the town’s combined sewer system (as had been the case pre-1937 before the culvert extension was created and at which time the culvert had fed directly into the sewer network). No conclusion in the report of the part played by the defective tidal non-return flap. |
28/10/23 | PROBLEM: Flooding in South Terrace and Town centre from the same sources as January |
ACTION: Immediate sealing of manhole by Southern Water and installation of TEN pumps on the seafront. | |
2023 to 2024 | ACTION: Repair to tidal flap valve. |
NOTE: Notable that ten pumps were installed where previously only two had been put in. | |
mid-2024 | NOTE: Southern Water complete a detailed modelling of the surface water network in Hastings and conclude that other than in 50-year or longer repeat incidents, the 1937 design for the culvert outflow should not result in flooding due to surcharging at South Terrace as long as the tidal non-return valve is operating as it was intended and there is not the level of shingle blockage seen in Jan 2023 |