What can be done about the drains?
This is the opening “gambit” on a discussion that I am hoping will start to crystallise some suggestions – for now it’s a few statements and questions for debate. Which I will correct/update as things are clarified.
1. Statement: There are two intended and one unintentional source of water reaching the beach.
(i) Added by Nigel Blacow: Road gullies (that take surface water from adjacent public roads and footpaths) and the associated drainage are the responsibility of Wirral Council, via the Highways dept, not United Utilities (UU are responsible for most other public /shared sewers but they are not responsible for private drains/soakaways that only serve one property. These are the responsibility of the property owner). When the Promenade was built in the 1890’s the outlets were probably nearer the top of the wall than the bottom but now because of rising sand levels they are either close to the bottom of the visible wall or buried under the sand (Kings Gap end of the prom, in particular). The gullies are designed to ‘trap’ solid debris, in the surface water running off the road surfaces and so need to be regularly cleaned out by a tanker using a suction hose. Because sand blows onto North Parade and surrounding roads and ends up in these road gullies, they tend to block up more quickly and as I believe Wirral only own one suitable tanker they arent cleared as frequently as required. When they are cleared the drainage outlet pipe to the sea wall is also frequently blocked, so this has to be cleared using a high pressure water jet and this can inevitably result in some dark silty residue being left on the beach. The possible contaminants in the surface water and/or this debris are many and their impact on the beach flora and fauna are unknown. In March 2020 Natural England advice to Wirral council said – ‘Natural England advises that the water quality should be tested to understand the contamination risks, better managed and regulated.’
There are approx. 23 road gullies on North Parade and there are currently 10 visible outlets through the sea wall, these outlets generally coincide with the roads leading down to North Parade. At the Kings Gap end of the prom the council have confirmed that some of the surface water outlets are so deep under the sand that they have been unable to locate them, with the limited resources available, and that trying to keep these clear is no longer practical or viable!
(ii) Rainwater from the seaward side of North Parade properties [lanwdard feeds into the main sewers], some of which are soakaways and some have outlets onto the road and some may drain onto the beach Added by Nigel Blacow The council have said they intended to map as many of the surface water drainage points and pipes as possible but due to covid and lack of resources this doesn’t appear to have been completed.
(iii) General water table from the soakaways mentioned, and broken drains and possibly water from further afield [Hoylake Carrs] building up behind the sea-wall and leaking through in places. I heard that the foundations for the new flats on the site of the old fire station hit water unexpectedly high and that council test bores on the promenade did likewise
Added by Nigel Blacow Given the age of these drains, it is highly likely that some are broken or leaking but this is unlikely to be a major factor and will just add to the general groundwater. From close observation of the beach over some years it is apparent that in addition to the surface water from the roads etc. there is also an element of groundwater, from many sources, that finds its way to the beach. The majority of this groundwater probably come from the fields and golf courses behind the developed area of Hoylake, which tend to flood following long periods of heavy rain. This groundwater must percolate under the ‘built up’ section of Hoylake down to the beach, which is at a lower level and it is probable that this is the main source of seepage through the sea wall. With regard to the prom and sea wall it is a historic fact in the past Wirral have injected cement grout under the concrete surface of the prom to fill the voids caused by water movement and minimise any resultant settlement.
2. Question: Where can the drainage water be taken?
Is the only choice further out towards the sea, where there is still sweeping? Drainage from the houses could be diverted to the sewers, but the drainage from the roads would have to flow uphill to go anywhere else.
Added by Nigel Blacow There are a number of possible alternatives, so far –
a)Natural England, in their March 2020 report said – Natural England advises that it would be better for the local environment for land drainage/ run off to be collected, treated and then discharged via a regulated discharge point. There may be opportunities for wetland creation landward of Hoylake or further along the coast and these areas could receive this treated water.
b)Divert the surface water into the combined public sewer that runs along the landward side of North Parade. It is unlikely that UU would be very receptive to this suggestion. It would add a large volume of surface water to the sewage going to the treatment plant and this is undesirable for a number of reasons, practical and financial. It would also be a major civil engineering project and have significant costs.
c)The surface water could be ‘managed’ using SuDS (Sustainable Drainage – susdrains.org) principles. This is a nationwide initiative to better manage surface water, by allowing it to be dealt with close to its source, rather than piping it elsewhere. This generally involves use of correctly designed, engineered and constructed soakaways, reed beds and/or attenuation tanks. The recently published ‘Masterplan’ (i.e. a record of development in Hoylake and some ideas for the future, based on local consultation) produced by AECOM consultants for Hoylake Vision, outlines some details of how this solution might be incorporated into a remodelling of North Parade and the promenade.
Added by Steve Taylor: In Liverpool in the eighties a massive interceptor sewer was constructed from Garston to Bootle which intercepted all of the old Victorian sewers that were previously discharging directly into The Mersey. This sewage was then pumped to I think Sandon Dock treatment works. Perhaps a similar interceptor sewer could run the length of the promenade at Hoylake gathering all of the surface water and road drains to a more suitable outlet point east of Meols? A big and expensive undertaking.
3. Question: What are the contaminants in the water?
The current assumption is that is heavy metals, inorganic salts, aromatic hydrocarbons, and suspended solids from road runoff plus pesticides, fertilisers and plant waste from gardens.
4. Question: Could the developing green beach form part of the solution?
For example is there any way to use reed-bed water purification before discharging the water into the sea?
5. Question: How much is it likely to cost to fix the drainage issues, and are there any grants still available now we are not EU members?
The Landfill Communities Fund could be a potential source of funding [thanks Lisa].