Flooding

If you are unfamiliar with the regular flooding from the proposed site, please click here for an illustrated summary.

 

Witney Flood Review July 2007 (Environment Agency)

 

(Extract page 5)

‘During the flooding of July 2007, approximately 240 properties flooded, some of which were from surface water flooding [e.g. Hailey Rd Drain] rather than directly from rivers bursting their banks.’

 

(Extract page 10)

‘The Hailey Road Drain flooded severely on Friday 20 July, as a result of the rain that fell that day. The catchment area for the Hailey Road Drain is 4.7km², and the main river section [NW SDA area] is relatively short.

However, the gradient is steep, and much of the immediate area is heavily developed.

 

[Eastfield Rd & Hailey Rd] Coupled with the saturated ground conditions from rainfall in May & June, the rate of rainfall run-off for the area would have been very high. This means that the time between rain landing in the catchment and finding its way into the watercourse would have been very short, leading to a high peak flow.

 

The majority of the main river section of the Hailey Road Drain is culverted [along Eastfield Rd & Hailey Rd], and as such it has a limited capacity. This was easily exceeded during the flooding, and by some significant degree. This led to an alarming flow travelling overland down the Hailey Road at very high speed.

 

The flooding on the Hailey Road should be considered the most significant flooding in Witney, at least for the July 2007 event, because it posed the biggest threat to life.

 

Witnesses talk of the difficulty of wading through the floodwater, and the fact that some manhole covers had lifted, leading to one vehicle breaking down after it drove over an open manhole at high speed. The speed that the floodwater travels down Hailey Road and the fact that manholes are known to lift mean that there is a risk to life when flooding occurs.’

 

Source: for the full report, click here

 

Witney Flood Investigation Report Dec 2020 (extracts)

(Prepared under Section 19 by OCC, released Jan 2022)

 

1.3. Previous flood events (2014)

…‘In December 2013 - January 2014, flooding was also experienced in Witney. Internal flooding was reported in West End (including the industrial Estate), Bridge Street and Riverside gardens and also highway in Eastfield Road and Hailey Road flooding [Hailey Rd Drain] which was witnessed on the 23rd and 24th December.’

 

2.1. Summary of December 2020 Floods

‘It was deemed necessary to complete a formal investigation into the flood incidents in Witney due to the number of properties that reported flooding internally.

At least 54 residential and business properties were confirmed as flooding internally on the 23rd and 24th December 2020. This included residents at Mill House Care Home, Riverside Gardens and Riverside House needing to be evacuated. Surface water flooding of some roads first occurred during the 23rd December 2020 in a number of places in Witney.

The amount of rainfall and its intensity that fell on that day overwhelmed some parts of the highway drainage systems which are very reliant on outfalls to watercourses which had started to become compromised by the rising river level. This was followed on the 24th December 2020 by river flooding when the upstream catchment flows [e.g. Hailey Rd Drain] reached Witney and river levels peaked. The level peaked just after midnight on the 25th December 2020.’

 

Full reports below:

North Witney (Land) Consortium’s history of proposals to solve the flooding problem.

 

Since 2014 we have witnessed four different proposals from the North Witney (Land) Consortium in their attempts to ‘solve’ the problem posed by the very high water volumes resulting from the Hailey Road Drain, a natural, but increasing, main river tributary.

  • In 2009 NWLC claimed that ‘balancing ponds upstream’ would be the solution.

  • In 2011 they introduced the idea of a 6 layer ‘cascading water storage’ system running in-line down the central area of the site.

  • In 2017 it was the proposal to have 6 attenuation ponds situated off-site north of the NW SDA. This 6 pond proposal would require a ‘reservoir’ classification through holding 63,000 cubic metres of storm water.

  • Most recently, in Nov 2023, NWLC’s Illustrative Masterplan revealed approximately 15 on-site, dispersed, attenuation ponds. The Consortium claimed that they will operate at up to 1.1m (3’ 7”) in depth when in flood.

The North Witney Action Group has no confidence that this life-threatening flooding problem is anywhere nearer being solved.

 

WODC as local planning authority and Oxfordshire County Council as Lead Local Flood Authority (LLFA) should be far more pro-active, open and transparent about what they intend to do to ensure this increasingly dangerous and potentially life-threatening situation gets the attention it rightly and desperately needs for the residents of Witney.

 

 

This is a video of the Hailey Road Drain in flood and its devastating effects on both Eastfield Road and Hailey Road.

 

 https://youtu.be/TjzAzl4GXw8

 

 

NWAG Conclusion:

  • Witney and its residents are likely to be little or no better off from local flooding issues.
  • WODC will have failed in their duty to alleviate this situation should this conclusion prove to be correct.

 

Sources for reference:

 

December 2009 North Witney Consortium booklet

 

January 2012 Meridian pamphlet

 

March 2012 Meridian statement of commitment for WODC

 

December 2012 North Witney Consortium Development Framework

 

September 2020 Meridian highways document