We have created a diary to cover the works to the seawall at Westover, Milford-on-Sea.
On a wet day on 19 August 2020, work with Earlcoate Ltd began.
Containers for the office and welfare facilities for the groundsmen were delivered to Paddy's Gap car park along with an articulated lorry load of Heras security fencing.
The Heras was erected to form a compound on the open space, whilst allowing pedestrian access along the clifftop.
The access along the top was briefly restricted to allow deliveries to take place.
By the 24 August 2020 Portland limestone rock was being delivered in 20 tonne loads by road.
This rock was to build an access road along the lower promenade that to allow plant access and material deliveries to the working site, further east.
A compound adjacent to the area of work was set up this week.
This would be the main site for the operatives to base themselves in.
The footpath from Ravens Way had additional stone added to the track for wider vehicles to access and the vegetation was trimmed.
The majority of the welfare and office space are to be located here and includes special bunkers for personnel to sleep in as the works will need to be undertaken at all hours to coincide with the low or high tide, depending on the operation.
28 August 2020 saw the start of the access road construction process.
Some of the limestone was used to add additional width to the track at the bottom of the slope and once the dumpers could navigate down the slope safely they were then used to haul rocks down to the area at the bottom of the cliff that had been eroded by the seawall failure and the following storms of 2020 (Storms Brendan, Ciara, Ellen and Francis).
The bank holiday weekend at the end of August was followed by a hive of activity at Westover, Milford-on-Sea.
Rock deliveries continued throughout the week whereupon 1000 tonnes had been delivered to Paddy's Gap and much of it moved on down to make the access road along the lower promenade.
By 4 September 2020 the first machines were able to bridge the gap from the access road through to the site.
The gravel bed behind the collapsed seawall was able to support the excavator adequately for the initial trip.
This enabled work to start on securing a safe working area around the failed section where the beach huts once stood.
The access haul road continued through the week. By the end of the week it extended a further 50m along the front, from the end of the stable seawall towards the old timber steps near to the broken groyne.
Smaller rock was brought in to fill in the gaps between the large rocks. This allows the dumper truck to navigate safely along the road. The large materials that are delivered to site from Paddy's Gap car park compound, such as the big green wrapped rolls of geotextile, will be transported along here to the working area.
The area where the beach huts once stood now looks very different. Work to the open space area and the route of the footpath was battered back and made a safe working area. The machines will use this as a refuge if there are any storms and the lower area will be used to access the front in order to place the rock delivered by barge.
Tuesday was a visit by the team to Southampton to see the Hagland Saga deliver the first load of Norwegian granite. A berth has been hired to store the rock before delivering it to site. The quay had to be protected so a base was laid of geotextile then glass sand and crushed concrete. This stops rocks dropped from the ship onto the quay from damaging the concrete.
At the same time the tug was visiting the site to see how close it could get to the seawall. The granite needs to get as close to the shore as possible. The excavators need to go and pick each rock up to place it in the revetment. The tug was a bit too far offshore so the way to get the tug closer is to have a convoy of vessels with the tug pushing a multi category vessel and then the barge loaded with granite.
The Yokohamas were delivered to site so that they can be placed on the seaward side of the seawall to protect it from any vessels that may come in to contact with the wall. By Friday the work to stabilise the seawall had begun. The excavator had a Movax pile driver attached. The Movax is used as it fits onto the excavator and can be used for different site and soil conditions. It vibrates the metal sheet pile into the ground and is then linked to the seawall by a metal rod and then tied in place with a bolt on the face of the seawall to stop the wall falling over.
The access haul road construction continued. The full length was completed and the gap bridged by the end of the week.
This allowed the geotextile rolls to be moved to site and will also provide an alternative route for rock deliveries to site should bad weather stop rock being delivered to site by barge.
Piling for the wall stabilisation was completed on the main section of wall towards the White House. The piling of the smaller corner section of wall that is still standing will be undertaken later as doing the work now could be cause access problems around the site.
The tie bars were installed within the trenches as can be seen in the photo. The drainage from the local properties was also considered. A new section of pipe was laid to take the surface water flows from the properties out through the seawall and revetment. The final connection will be made once works in the area are complete.
On Tuesday 15 September the first rock delivery was made to site. The operation involved four different vessels. The tug, Afon Cefni, brought the rock loaded on the barge at the dockside, down Southampton Water around Hurst Spit and then waited just offshore. The Liftmoor, a shallow draft multi-category craft, then left its berth at Lymington and sailed round to meet the Afon Cefni. The Liftmoor then took the barge from the Afon Cefni and pushed the barge close to the beach so the rock could be unloaded in a suitable location for collection and placement. The fourth vessel the Susan Mary provided support to the other three.
The rock deliveries continued at a rate of one delivery per day for the rest of the week with each barge load containing 300-400 tonnes. The scheduled rock delivery on Saturday was not possible because of the rougher weather and a larger sea swell. By Sunday September 20the the wind had shifted direction and the deliveries resumed.
The first three deliveries of rock were used to create a temporary access onto the foreshore for the excavators.
Subsequent deliveries were unloaded near where the first sections of revetment are going to be built towards the White House.
Worked has started on the existing timber groynes firstly to create a way through for the excavators at the sea wall end of the groynes and secondly to repair some of the damage to the groynes caused by recent storms.
Preparation of the foreshore has also started ready for the rock revetment construction.
Monday saw the second delivery of rock that would be used to create the revetment. This delivery was made to the second groyne bay along from the White House. It enables the contractor to have enough manoeuvring room to work when placing the rock. The space also allows the contractor to sort through the rocks to select the most appropriate rocks to place. When constructing the revetment it is important to have some of the largest rocks at the toe of the revetment. These rocks are placed into the clay strata, on top of a geotextile, that stops the revetment from settling too much.
Tuesday was bright and calm seas, Wednesday was a bit more overcast but the sea state allowed for work at low tide and rock deliveries at high tide. This allowed construction of the revetment to reach up to the first groyne from the White House heading west, approximately 25m of revetment has now been built. Wednesday the Hagland Saga delivered the second load of 4500 tonne of rock to make the 9000 tonne ordered. The stockpile on the quay at Southampton waiting for delivery to site is substantial.
With a low pressure arriving on Thursday and persisting through into Friday, the sea state became too rough to allow for rock deliveries by barge. With the surge from the stormy sea there was also a short working window on the frontage that meant revetment construction could not take place. Making allowances for the weather is one of the factors that has to be dealt with in coastal construction projects. It is accepted that some days will be lost to the weather and is factored into the works programme. This meant though that there was time to do some repairs to the timber groynes. A pile was driven into the beach next to the first existing pile as a support. The existing groyne pile needs some support as it would now be a freestanding pile at the toe of the revetment because the rear section of groyne had to be removed in order to build the rock revetment. The additional pile supports the groyne during construction when the beach is excavated to the clay strata for the toe rock. If any scour occurs around the toe of the revetment once it's completed, this support will help to keep the pile vertical. Other vital jobs were also undertaken during this time, such as maintenance on the equipment and work within the compound to keep the living quarters habitable.
Over the Saturday the sea state remained too rough for a rock delivery. But Sunday saw a calmer sea and bright skies so a rock delivery was achieved in the morning. This is adding to the stockpile on site that is now waiting to be placed in the desired profile of the revetment.
Another barge load of rock was delivered to the site on Monday and building of the revetment continued westwards. By Tuesday the total length of revetment built was 40m. The barge attempted a delivery on the Tuesday morning but the swell and waves prevented offloading of the rock. Work was able to continue on repairing and shoring up some of the timber groynes. Some new, longer piles were driven into the beach next to the existing piles to give additional support to the groynes. The deteriorating weather and the arrival of Storm Alex meant that no further barge deliveries of rock were possible until Saturday, once the storm had passed. However, work building the rock revetment continued using the rock that had been stockpiled on the beach, and by Sunday the total length of revetment built was 44.5m.
A further week of poor weather resulting in significant waves and swell at Milford-on-Sea prevented any rock deliveries by barge. As this weather was forecast, Earlcoate had arranged for the granite to be delivered to site by road. Monday saw the first of three low loader lorries arrive with granite. To enable an evenly distributed load for each rock is weighed and placed appropriately for transport. So, the rocks that can be seen in the compound all have their weight sprayed on. These rocks are offloaded into Paddy's Gap car park compound. From here they are loaded into the dumper and taken down to the site on the haul road. By Friday 2000 tonne of granite had been delivered from Southampton this way.
A section of the revetment was able to be constructed during the week, even though the weather was poor and the working window short.
Sunday saw a break in the weather enabled a much-needed delivery of rock to site by barge. This method of delivery is the most efficient but weather dependant. The barge was able to place the rock in the groyne bay ready for use next week. The forecast is showing an improving picture allowing for timber groyne refurbishment and revetment construction progression.
From the expected bad weather to the sublime, what a difference a few days makes. This week saw six barge loads arriving on site. Monday was rough seas so the granite continued to be delivered by road but barges arrived every day for the rest of the week. The last barge load from Southampton took place at the end of the week on the Saturday, leaving the quay all but clear of rock. There was only a part load of granite for the barge so the marine based vessels were off hired and sent to their next job. The last few rocks were to be delivered by road over two days in the following week.
Monday was still a good day, the council authorised the purchase of an additional 3000 tonnes of granite from Norway. This additional rock would allow a small revetment to be constructed along the western section of the failed seawall.
During the working days this week further deliveries of rock arrived from Southampton by road. The rock was stockpiled at Paddy's Gap car park and the dumpers were used to transport it to the base of the cliff ready for placement. The gap between the haul road of limestone and the failed wall was filled. This allows for a new access to the western side for revetment construction.
Due to the good weather and the increasingly good tides the revetment construction continued apace. Monday the revetment length was 50m and by the end of the week the total length built was 75m.
The timber groyne works were also enabled at the low tide. The timber groynes being refurbished using the timbers that had been retrieved from the sections removed and from timbers that the council had in store. Three groynes have now been refurbished and should last a little longer. This work should help manage the shingle that moves along the front.
The early hours of Monday morning saw the continuation of the revetment build. The dark hours require floodlights to light to area of work. The two lighting towers sit on the higher level of the promenade and the flood beams are shone onto the lower beach level. This directional lighting allows work to be undertaken during the low tide night hours. It also means that the light does not impact on the local homeowners.
Tuesday night on the low tide saw the first ramp being dismantled. This is so that the rocks in it could be placed back into the correct profile. The designed profile is the dimensions and shape that the rocks are placed. The design allows for the wave action to be dissipated before reaching the seawall. The voids also trap the shingle, slowing the long shore drift and adding additional material support to the base of the seawall. The weather forecast was looking less than ideal, and the tides were increasing as the week progressed towards the neap tides. Monday and Tuesday Earlcoate made hay whilst the sun shone, because after that the tidal surges prevented further construction. From the 75m length built last week, progress was made by another almost 20m, giving a total of 94.2m completed.
Timber groyne pile driving has been completed on the two remaining groynes by Tuesday. These additional, upright piles are longer than the original piles and will give the added support needed for whole groyne and the adjacent pile. Additional planks will be added later during the next set of spring tides.
The remaining granite on Southampton Quay was transported to Paddy's Gap car park compound. From there, the rocks were transported to the front and used to create a second ramp across the failed seawall in the west, towards Hordle Cliff. Once this ramp was complete the rocks that came down were stockpiled ready for use. They line the seawall and the base of the cliff in places. The rocks at the base of the cliff have been placed there to try and temporarily stabilise the cliff. The stormy weather has caused some new cliff slides with rainfall, winds and sea spray destabilising the base and the weight of the land above causing the falls.
Following the Council meeting last Monday and the permission to purchase another 3000 tonne of granite, the coastal engineers ordered the rock from Norway. We await the delivery that could take two to three weeks. Whilst we wait the original revetment end can be redesigned and reprofiled to make way for continuing west and join to the existing revetment. Again, once the profile of the new revetment section along this line of failure has been designed the rock will be moved and placed appropriately.