Initial Assessment – Flood Mitigation Options
Upper Great Ouse Catchment flood mitigation and avoidance planning.
This document is a starting point for a review of all the options available for flood mitigation and avoidance across the Upper Great Ouse catchment. The list is intentionally broad and includes potential physical interventions, maintenance activities, investigations, monitoring, infrastructure improvements, planning measures and opportunities for partnership working. The options will be expanded, investigated, and documented as the IA progresses.
1. Natural Flood Management – EA, BCC and BTC.
a. Leaky woody dams
b. Scrapes
c. Wetland creation – Ponds, Reed Beds etc.
d. Tree planting
e. Riparian tree planting - stabilising banks
f. Cross slope woodland/hedges
g. Re-meandering
h. Flood plain reconnection
i. Soil aeration – restoration
j. Runoff management
k. Cover crops
l. SUDS – rain gardens, planters, permeable surfaces, etc.
m. New developments to use rainwater harvesting for toilets, etc.
2. Removal of Wiers (see documents on weir removed by the University/Mill) - EA
3. Removal or replacement of Bridges – pinch points (“Pack horse bridge”) - BCC- Owner see Drainage Asset Register ID 9222cb1c-2760-497b-847f-4805f5692391
4. Installation of a water control tilting weir at Tingewick Mill along with flow gauges – EA - Owner
5. River clearance – expand with volume diagrams and flow diagrams based on river cross section full of organic matter and then clear of organic matter - EA
6. Flood plain condition and depth lost by silt deposits over the last 100 years plus – Riparian Owner
7. List all the Environment Agency suggestions presented after 1998 flooding and the reasons why they were not acceptable (there are 6 suggestions?) -
Environment Agency/Anglian Region Buckingham Flood Defence Improvement Scheme Project Appraisal Report (Final Report 2005)
Option Description
1 ‘Do nothing’
2 ‘Do minimum’ (preventative maintenance)
3 Upstream flood storage at Water Stratford
4 Diversion channel around Buckingham
5 Channel improvements through Buckingham
6a Flood defences through Buckingham to a 1 in 50 year SoP
6b Flood defences through Buckingham to a 1 in 75 year SoP
6c Flood defences through Buckingham to a 1 in 100 year SoP
7a Combination of upstream flood storage (140,000 m3 volume) and flood defences through Buckingham to a 1 in 50 year standard
7b Combination of upstream flood storage (140,000 m3 volume) and flood defences through Buckingham to a 1 in 75 year standard
7c Combination of upstream flood storage (140,000 m3 volume) and flood defences through Buckingham to a 1 in 100 year standard
8a Combination of upstream flood storage (340,000 m3 volume) and flood defences through Buckingham to a 1 in 50 year standard
8b Combination of upstream flood storage (340,000 m3 volume) and flood defences through Buckingham to a 1 in 75 year standard
8c Combination of upstream flood storage (340,000 m3 volume) and flood defences through Buckingham to a 1 in 100 year standard
8. List clearances required downstream at Stony Stratford, flood plain depth, culverts, walls built across culverts, weir removal – AN and IM
9. List all the same works required from Brackley through to Bedford – locate/contact flood groups AN and IM
10. Check Lidar survey suitability and requirement for GNSS – EA Question
11. Check for threshold survey data for flooded properties – EA Question
12. Check for possible implementation of depth “poles” either side of structures following on from GNSS survey – FA4B – Riparian owners
13. Check bridges and other structures for silt deposits, present diagram of how to clear upstream and downstream of a bridge or other structures to ensure no silt deposits are left in normal flow (20ms either side)– need diagrams.
14. Implement fish bypass for weirs in Buckingham that are blockades - EA
15. Implement hydroelectric Archimedean screw generators – EA
16. Reprofile Ford Street ford to remove weir effect - Highways
17. Identify Riparian owners on contact DB
18. Identify responsible parties for package of activities – add to list and to any future additions.
19. Reprofile road corners to redirect water flows to drains, away from properties, i.e. London Road and Chandos Road corner and Ford Street corner by BMC where the dropped curb allows the water to bypass the drain.
20. Buckingham Canal Society and WRE plans to transport water from Buckingham to MK for cleansing and storage, fix problems at source and stop putting pollution in the river.
21. Publicise the “Washing Machine” water being put down surface drains and polluting the rivers adding another pollutant and problem.
22. Culverts under the ring road, reprofile area to control flows.
23. Drains and culverts inside and outside ring road flows and directions
24. Drains from Page Hill flowing down inside/outside ring road
25. Split surface water from sewage and flow accordingly
26. Anglian Water treatment plant expansion – capacity increase and therefore cope with storm water run-off through combined drain network
27. Drop road and pavement levels, especially around low threshold property.
28. Clean Drains in risk areas on a quarterly cycle – not every other year or so. Manage with affected residents to ensure access for “first visit fix”
29. Work with other Flood groups downstream.
30. Addition of new drains and gulleys for areas that have identifiable surface water problems.
31. Record and report issues with surface water and work with highways directly to communicate (D&G)
Precedent set where identification of no viable solution to flooding solved by purchase of flooded properties, Rhondda Cynon Taf County Borough Council, Chesterfield Borough Council and the Environment Agency (EA).