Problem located

Thursday 8^th May

Another day with complex logistics. With nine of the Drainage team attending for work at three sites we required three vehicles. S&T required another and so did the Heritage team – all of us taking advantage of a non-running day. With only four vehicles available, we needed a cunning plan!

Martin and Peter took the tipper Transit to Toddington to collect safety rails for the former bridge 41 south of Two Hedges Road. Neal from the heritage team had made these from scrap boiler tubes removed from Dinmore Manor. They then delivered these to the bridge site, where Neal and Joe installed them. Then with Stuart joining them, they headed back north, installing our prepared safety markers for the headwalls of cross drains 37G, 37E, 37D, 37C and 37B. These used recycled scaffold poles. They achieved the award for the most productive group of the day, as this enabled five tasks on our ‘To Do’ list to be marked complete.

Nigel, Polly and Roger had the blue tail-lift Transit, carefully loaded with a cement mixer, a supply of sand and bricks and some heras fence panels. They offloaded the bricks, sand and mixer offloaded at Two Hedges Road and then took the fence panels a bit further south to the Bonsai World stream entry. Once the third vehicle arrived with cement and water; they started on the final brick courses for the rebuild of down side inlet chamber of syphon cross drain 39B.

Good to have our master bricklayer Polly back after an illness. He soon had the final couple of dozen bricks laid on the 39B down side inlet.

Blue mesh lid on the 39B inlet is temporary; once the mortar has fully set we will replace this with concrete lids.

Andrew, Dave and Stuart were in vehicle three (the Isuzu) and Jonathan made his own way to Two Hedges Road (Bishops Cleeve). Once the materials for the brick laying were offloaded; they continued down to the Bonsai World stream. After coffee break, a change of group memberships saw Stuart joining the safety rail installers, and Roger joining the investigators at the Bonsai World stream. Here, we had permission to remove a section of fence and enter the former Bonsai World site. This enabled a proper examination of the structure under the drive way and footpath. This turns out to be concrete blocks and slabs forming a 12 by 9 inch rectangular passage under the drive way. It is approximately 3m long where it terminates against a 450mm diameter concrete pipe which runs into the manhole on top of the cutting crest. It is the joins between the concrete blocks and the lack of a proper join between the rectangular section and the 450mm diameter pipe which is causing the leakage under the manhole and then down the cutting side to the down side cess. So we have found the cause of the problem. Our preferred plan to fix it, is to replace the rectangular block section with a longer section of 450mm diameter concrete pipe. Not only should that stop the leaks, it will also more than double the capacity of the bore, thus preventing the stream backing up and overflowing into the adjoining field. After very wet weather, this stream can be a raging torrent. A good job today it was bone dry. However, our rebuild plan requires excavation across the drive way and footpath; so we will need to obtain a temporary footpath closure authority from the County Council. That will take a few weeks at least – and no doubt by then the spell of dry weather will have come to an end.

Entry to the under drive way channel in the corner of the Bonsai World site.

 

Looking from the inlet side showing the joins in the concrete block sections. [Photo by Jonathan]

Looking back up from the circular pipe which enters the manhole showing the butt joint to the rectangular section. [Photo by Dave]

The 450mm concrete pipe which enters into the circular manhole. Just a inch or so of standing water in the bottom of the manhole - normally we have 6 or so inches here.

Before leaving we replaced the hole in the fence with a heras panel; and installed a couple more heras sections to plug gaps in the fence between the footpath and the top of the down side cutting.

Temporary heras fencing by the gate at the end of the drive way.

After lunch, we attended to some routine maintenance on three brush cutters. During the spring and summer, our colleagues in the Lineside Clearance teams are the main users of these. Changing spark plugs and air filters fixed two machines. For a third, we called in the expertise of Stuart from C&W; who diagnosed and then fixed a sticky carburettor diaphragm.

Wildlife report: Lots of birdlife spotted in the dense tree and vegetation growth on the down side south of Two Hedges Road bridge beside the drive way and footpath; including blue tits, robins, blackbirds, starlings, magpies. Plus a muntjac deer on the drive way. One item we missed on last week’s report was the sighting of brown trout in the River Isbourne.