Olympic update
  Missing the boat


I squeezed in one more Open House visit, rather closer to home, at a completed multi-million pound Olympic construction project. Not the Stadium, nor indeed anywhere that'll host a single 2012 sporting activity, but a big concrete barrier on the Bow Back Rivers. This is Three Mills Lock (at Three Mills), which used to be called Prescott Lock (on the Prescott Channel). It's supposed to be a key part of our commitment to a sustainable Games, enabling building materials to be shipped into the heart of the Olympic Park by water instead of by road. Open House provided one of the first opportunities for the public to get up close to discover how £20m has been spent, and to be shown around behind the perimeter fence by a very knowledgeable lockkeeper.

It's a bloody massive lock. After my walk along the Lea last month I'm used to much smaller structures with wooden gates and twee waterside cottages, but this is nothing of the sort. It's three channels wide, with each gate wide enough to take a 350 tonne barge. The gates rotate up, not across, a bit like the Thames Barrier. There's a fish ladder along one side to ensure that scaly finny creatures can still pass up and downstream. And operations are overseen from a squat narrow control tower mid-river, complete with home comforts like a shower for the personnel working within. It's the sort of lock you might expect to find on the Manchester Ship Canal, not on an insignificant East End backwater.

The key to the lock's existence is its location. Downstream the Lea is tidal, with water levels dropping to unnavigable levels for long periods each day. Upstream, now that Three Mills Lock has been built, water levels along the eastern side of the Olympic Park will in future remain constant. That sounds like great news for enabling the import of building materials and removal of waste by river, but unfortunately reality's not quite so simple. Tides in Bow Creek still prevent barges from reaching the lock for 16 hours each day, which cuts back the potential time this route can be operational. As an additional setback the Prescott Channel and Bow Back Rivers haven't been used for major freight traffic for several decades and so have long since silted up. Dredging the channels has taken considerably longer than expected, and so the number of Park-bound barges using the new lock has been, to say the least, disappointing. Just six barges since the lock opened in June, we were told, just six.

Now stop me if I'm wrong, but an average of one big barge per fortnight is a pretty unimpressive strike rate. The whole idea of funding the lock in the first place was to enable the transfer of waterborne cargo during the peak construction window, and that doesn't appear to be happening yet. To give you some idea of the scale of the problem, Three Mills Lock was originally planned to open last summer, four years before the Games themselves. But the body of the stadium's already up, absolutely none of which has arrived by river, and there's a very real risk that few of the building materials for the remaining stadia will arrive via this watery route. The Park's location slap bang beside Stratford station has allowed use of a far more convenient sustainable mode of transport, and that's rail. Who needs slow meandering river traffic when freight can arrive more easily by train (or, to keep costs down, even by road)?

It looks increasingly likely that Three Mills Lock will prove a construction-time white elephant, but a legacy-phase saviour. By stabilising water levels throughout the Olympic Park, the completion of a post-Games residential 'Water City' now becomes possible. Swish riverside apartments, swanky cosmopolitan cafes and bohemian aspirational culture - all suddenly enabled because the Lea no longer drains away every 12 hours to reveal discarded supermarket trolleys and mud. Three Mills Lock adds millions to the potential value of future properties to be erected further upstream, which can only help to pay back the investment our taxes have poured into Olympic funding. But the lock itself looks destined for an underused future, ridiculously large for the few pleasurecraft that might use it post-2012, and never quite the ecological showpiece it set out to be.

• Nobody seems quite sure when the footpaths around the lock will reopen, which is annoying for those of us who used to use it regularly.
• Here's a collection of photos of Three Mills Lock, taken by Mat over the weekend
• Bits of the Euston Arch were dumped in the Prescott Channel, you may remember.
• Legacy plans for the Olympic Park are detailed here (and on this interactive map)
• Local residents in Bromley-by-Bow may be interested in Tesco's plans to erect a replacement superstore at Three Mills, relocated slightly nearer the railway, forming the heart of a new district centre for Tower Hamlets. Plans will be on display at Tudor Lodge this Friday (noon-7) and Saturday (11-4).