Background reports
Links will be provided here to reports from the Environment Agency, B&NES, Bristol Water etc.
The Secretary holds hard copies of the following UWE maps:
a) For Chew Magna:
- Surface Water Flow Accumulations and Directions
- Surface Water Flooding 30 year and 1,000 year eventsb) For the area bounded by Winford, Dundry, Pensford, Bishop Sutton, Chewton Mendip, East Harptree and Compton Martin:
- Land
Elevations and Slopes, Surface Water Flooding, Groundwater Flooding, Soil Units, Standard
Percentage Runoff,
Relative Runoff Generation,
Soil Storage Potential, Geological Permeability Index, Combined Subsurface Storage Index.
- Briefing
paper Chew
Magna Flooding - September update pdf (click to open). The
briefing also includes links to the following four reports, but links
are individually provided below.
- Briefing paper Chew
Stoke - What we have been doing pdf (click to open) also includes
the links
November 2017 A research degree project by Richard Pardoe assessed the potential for land-based schemes to reduce flooding in the Winford Brook catchment. Potential schemes include the creation of 'run off retention' ponds. His report is entitled 'Identifying and prioritising landscape-based surface water management interventions in the Winford Brook catchment.' ( Report pdf, large file, click to open) is attached.
April 2017 Ricardo Energy and Environment report for Bristol Water, entitled 'Bristol Water Chew Valley Reservoir Resources NEP Investigation Phases 2 & 3'. A review to assess the impacts of the reservoir on downstream ecology - attached here (pdf, click to open). An Appendix is attached here (pdf, click to open).
November 2015 Eunomia Research and Consulting Ltd
published a detailed technical report on the Winford Brook catchment,
in particular aspects such as silting and soil erosion, and flood risk
reduction (para 2.6 in main report). The report and accompanying slide
presentation are attached here: 'Payments for Ecosystem Services - Round 3: Winford Brook PES Pilot Research Project' Report (large pdf file, click to
open) and here Slide Presentation (pdf, click to
open).
B&NES published in September 2013 the four reports from JBA Consulting into the 2012 floods and the performance of the property level protections installed in 2010-11. B&NES together with the EA and Bristol Water also issued a briefing paper covering Chew Magna, with one covering Chew Stoke to follow shortly.) Click on the links to the briefing and all reports below:
- JBA Consulting - Chew
Magna Flood Investigation. Final Report 2011-12
pdf (click to open)
- JBA Consulting - Chew
Magna Flood Investigation. Technical Report pdf
(click to open)
- JBA Consulting - Chew
Magna Property Level Protection Scheme Evaluation Final Report
pdf (click to open)
- JBA Consulting - Chew
Stoke Flood Investigation. Final Report 2011-2012 pdf (click to
open)
18 August 2015 Chew Magna Flood Modelling. At
a public meeting on 28 July 2015 the Environment Agency gave a
presentation of their computer modelling exercise into the September
and November 2012 floods. Copies of the two sets of presentation
slides are attached (Chew
Presentation July 2015 and Chew
Magna Model Presentation Final click to open. The EA has also
provided a set of maps showing the flood extent and the modelling
impacts - these maps are in the attached Word document (Maps
click to open). Their modelling assessed the potential for
reducing flooding levels under a range of possible scenarios
including reducing water levels in the reservoirs, altering the
confluence of the River Chew and Winford Brook and removing the
bridge on the B3130. The modelling results indicate that such actions
would have not reduced the 2012 flooding sufficiently to have
prevented property flooding.
April 2015 JBA Consulting 'Upper River Chew Hydrology and Model Update' Final Report April 2015' - a detailed technical review for the Environment Agency of the hydrology and modelling conducted after the 2012 flooding - report (pdf, click to open). (The JBA interim report dated Feb 2014 is attached here (pdf, click to open).) JBA also published an accompanying document 'Flood Estimation Calculation Record', attached here (pdf, click to open).
2 June 2014 The Department
for Environment Food and Rural Affairs (DEFRA) has published (pdf
attached
click to open) 'Best Practice in Property Level Protection
Systems - Advice for Local Authorities.' This gives advice on the
best practice to follow when procuring and installing property level
protection systems. The best practice is based on evaluation work
carried out by JBA Consulting. JBA Consulting also prepared the
major reports into the 2012 Chew Magna and Chew Stoke floods, and are
also managing the current Chew Magna project to enhance property
level protection.
15 May 2014 Proposed drainage improvements on Tunbridge Road The Drainage and Flooding Team at B&NES have provided a draft drawing (attached, pdf click to open) showing the drainage improvement works proposed for Tunbridge Road. The aim of the scheme is to remove obstructions from the drains to restore full capacity. At the same time the gullys will be improved to maximise the inflow of water and minimise the potential for grills blocking and pots silting up. An additional gully is proposed to replace a failed soakaway which was removed a while back. Improvements are also to be made to the chambers on the system to allow better access for inspection and maintenance.
4 May 2014 Drainage matters in Chew Magna and Chew Stoke In April the
Co-Chairs contacted B&NES drainage section to ask for a response
to a number of questions about cleansing of drains and gullies in the
area. The questions and the B&NES reply are attached
(Word doc - click to open).
3 April 2014
Flood Warnings - notes on a meeting held with the Environment Agency on 28th March attached
(Word doc - click to open). The meeting was called to consider
how Flood Warning forecasting can be improved.
11 March
2014 Co-Chairs Rachel Wilson and Mike Curtis submitted questions for
response by B&NES Planning, Transport & Environment Scrutiny
Panel meeting on 4 March 2014. These questions covered issues such as
outstanding matters concerning UK Flood Barriers, how the £200,000
allocation for Chew Magna PLP will be disbursed, and the proposed
Strategic Flood Risk Management Group. The full list of
questions asked, and the Scrutiny
Panel response, is attached here (Word doc click to open).
1
February 2014 CVFF Co-Chair Mike Curtis exchanged emails in early
January with Bristol Water requesting action to reduce the water
level of the Chew Valley Reservoir, because of the risk associated
with high rainfall coupled with a full lake. The text of these emails
is attached modelling Lake
level reduction request 06 01 20 , Word doc click to open).
Subsequently Mike exchanged emails with Ed Lockington and Joby Graham
(Environment Agency), and this correspondence together with Mike's
comments and update is attached (Lake
level reduction iss Jan 2014. Word doc click to open).
24
January 2014 Chew Valley Reservoir levels and drain off
matters. Attached are two pieces of correspondence between the Flood
Forum and Martin Berry of Bristol Water relating to the issues around
active management of water levels. 1) Martin
(Word doc, click to open), and 2) BW
Response to 22 Oct questions (pdf, click to open.)
10 December 2013 Responses
from B&NES & the EA to questions raised by Chew Valley Flood
Forum concerning Chew Stoke (pdf, click to open) Following the
flooding in Chew Stoke in 2012 Bath and North East Somerset Council
(B&NES) and the Environment Agency (EA) commissioned an
investigation into the floods. The results of the investigation were
published during September 2013. This joint document with B&NES
and the EA forms a response to questions raised by members of the
public and the Chew Valley Flood Forum regarding the contents of the
reports and other related issues. The EA have also provided the
following document Chew
Stoke Flood Risk Workshop Property Level Protection (PLP) Frequently
Asked Questions (pdf, click to open).
4 December 2013
Responses
to questions raised by Chew Magna Flood Forum (pdf, click to
open) Response from B&NES, Bristol Water and the Environment
Agency to the questions raised at the Flood Forum meeting on 1
October and also at the Public Meeting on 8 October.
28
November 2013 Report
(click to open) on the meeting (attended by the Co-Chairs of the
Flood Forum) of the B&NES Planning, Transport and Environment
Scrutiny Panel on 20 November to discuss progress. Also, the Response
from B&NES (click to open) to the questions which the Flood
Forum sent to B&NES before the Public Meeting on 8 October.
23
November 2013 Bristol Water have prepared for the Flood Forum a
Technical
note (click to open) on the operation, capacity and management of
the Chew Magna Reservoir. This restates the point made, e.g. on page
20 in the Chew Magna Flood Investigation Final Report (see below)
that this reservoir has limited capacity to cope with high levels of
flooding. This aspect is to be looked at in more detail when the
modelling software becomes available (hopefully by the Spring).
4 November 2013 In early October we posted an email to Rachel Wilson, Co-Chair, from the Environment Agency about river/brook maintenance of is attached as a Word document (click to open). Associated with that email we posted EA maps and other information concerning river maintenance for the Winford Brook and River Chew at Dumpers Lane. The Environment Agency have now provided revised maps because they felt that the previous ones were not clear enough. They have also provided details of their 'check rounds'. The EA states that check rounds are undertaken when they are expecting heavy rain and high flows in the rivers, and that they check bridges, culverts, weirs, etc to ensure they are free from debris and blockages. The new documents are: Chew Magna Annual Maintenance (Dumpers Lane) (pdf click to open); Chew Magna Check Rounds (Dumpers Lane) (pdf click to open); Chew Magna Annual Maintenance (Winford Brook) (pdf click to open); Chew Magna Check Rounds (Winford Brook) (pdf click to open). Finally, the EA also state that "It is important to note that our current maintenance activities in Chew Magna are not guaranteed and can change depending on economic justification and our funding allocation from central government. In addition, as with all our work, maintenance has to be prioritised and justified technically, environmentally as well economically."