The technical design for the restored waterways is being undertaken in conjunction with expert consultants Black and Veatch and our Waterways consultant Paul Wagstaffe. The final design will depend in part on the navigation standard to be adopted, but also the conclusions of a number of feasibility studies and tests that are being undertaken.
A study based on existing maps and records available to Black and Veatch has already been completed and is the basis for the current planned waterway stages.
Our design discussions to date have focused on two alternative navigation standards for the waterway design. Accommodating narrow boats is the more demanding option, due to the minimum bridge heights and draft required, and some combination of the two standards may have to be used along different parts of the route to reduce the need for costly bridge works:
a) narrow boats of up to 60 feet, or;
b) small boats such as punts, canoes and rowing boats.
It is unlikely that it would ever be feasible to cater for full size river cruisers due to the headroom restrictions under many bridges.
Specialist engineers completed a levels survey of the York Stream and Maidenhead Flood Relief Channel (MFRC) sections of the planned waterways in May 2006, in order to confirm bridge and river bed heights, plus the stream widths and conditions at the various bridges that cross the existing channels.
Further initial survey work was undertaken at York Stream by MWRG members in August 2006 to locate and establish the height/position/size of existing outlets that drain into the channel. The final waterways design is likely to involve a combination of lowering the stream bed (by dredging) and raising the permanent water levels (assisted by one or more locks/weirs). The Environment Agency will need to approve the final design to ensure the proposed works do not add to general flood risk in the area.
All of the technical and outlet data acquired to date has now been incorporated into provisional engineering drawings of the proposed route by Black and Veatch. These include cross sectional drawings of the channel and bridges under which the stream passes, plus so called "Long Sections" showing the gradient of the channel along its route.
The latter are now being used to assess alternative target water levels for the restored waterways and their impact on headroom and the extent of bridge modifications needed. Once a final design is agreed, a provisional budget for the overall project will be completed.
The overall construction programme for the waterways will take some years and be paced by the necessary planning and other consents, plus inevitably our ability to attract grant and other funding.
We are hopeful that the work to allow narrow boats plus smaller craft up to Green Lane, with smaller boats also able to use the ' Ring ' around Maidenhead, at least, will be completed around 2012. The balance of Phase 1 would then be completed a few years later. Phase 2 north of Maidenhead would take a further few years if considered feasible.
DESK STUDY RESULTS
