Flooding History
The Village of Rossett has been subject to a number of planning applications over the years and these have always been opposed by Members of the Wrexham Council. The New Development North & South of Rossett Road was refused by Councillors but it was appealed and granted by the Welsh Minster on the advice of a Planning Inspector. The site was only approved because Wrexham needed houses somewhere in the Borough. The Planning Inspector actually endorsed the grounds the Council refused the application but the appeal was granted ignoring the following facts.
Flooding and Insurance Risk
The proposed development site abuts the River Alyn flood plain and the River has burst its banks many times in the last 50 years with drastic flooding to the village in 1976 and 2000. Residents living near this site have been refused flood insurance and mortgages for a number of years as the development site boundary along Harwoods Lane has been adjudged only recently by Natural Resources Wales (NRW) as level with the River Alyn flood plain.
The photographs that you see displayed on Banners around the Village are records of the surface water flooding that occurred in June 2019 and February 2020. The River Alyn did burst its banks but did not reach the development site on that occasion.
NRW categorically state that the sites are not at high risk of flooding but do not factor into their advice climate change which is a very real risk on land level with a flood plain, especially as both parcels of land are inherently waterlogged most winter months from October to March.
The northern parcel of land was included for development in the 1950s and was abandoned by the Council in 1958 when the houses facing the site in Trevalyn Hall View were evacuated due to the spring and aquifer under the land lifting the floor slabs warranting massive repairs before they could be re-occupied.
The old OS map below shows an aquifer and stream in North field. The large Alder tree growing in the field is at the point where the aquifer rises. In 2003 a Planning Inspector refused planning consent on the Northern Field due to historic flooding and advised a precautionary approach due to the flood risk.
In 2000 the November Flooding incident was so intense that the houses and bungalows in Trevalyn Way were sandbagged by the Council to overcome the massive run-off from the Southern Field into Trevalyn Way.
In September 1976 the flooding in the Village was even greater than 2000 and the high-water marks in Harwoods Lane and Gun Street were recorded by the Residents. Harwoods Lane in those days was just a country lane and the flood line was bounded by the large tree on the corner of Trevalyn Way and Harwoods Lane. Harwoods Lane was closed for a week cutting off the road to Trevalyn. The River Alyn reached a height of 2.89m above normal.
In 2000 the flood lines were almost as high, 2.79m above normal and the Wrexham Council Duty Flood Officer confirms the flooding extent to the village and that Harwoods Lane was breached by flood water almost to Trevalyn Hamlet which required sandbagging to prevent damage to the cottages on Harwoods Lane. We have in addition to that testimony of the Duty Flood Officer, statements from local residents confirming the height of flood waters on that occasion.
The speculators Flood Consequences Assessment (FCA) Report has plans for the gardens of the new properties to be flooded in the event of the drainage capacity (SUDs) being exceeded. This policy of garden flooding is deprecated by the latest draft TAN 15 that gives guidance to flooding matters in Wales. No apparent consideration has been given in the FCA to flood water run on or run off from the site.
Topography of North & South Fields
The Records held by NRW on flood levels in Rossett only commenced in 2010 when the defences along Station Road were strengthened and these indicate only a maximum River Alyn height of 2.19m above normal in June 2019.
NRW have never attended a flood incident in Rossett, they always relied upon WCBC to respond and they have no record of the 1976 event and their records for 2000 are derived from a Police Helicopter Flyby. Unless the Flyby took place, in full darkness at midnight on the 6th November 2000, then the height of flood lines established by local residents and the Council Duty Flood Officer cannot be disputed.
The 2000 flooding is known to have peaked at a height of 15.79m Above Ordnance Datum (AOD) at 11:45pm on 6th Nov 2000.
Note that the maximum elevation of these 2 fields is 13.82m. Also that no flood defences exist in this area of the River Alyn. (The only flood defence in Rossett is in Station Road).
Flooding run-off is illustrated by the topographical map derived from the speculators data. The South field was subjected to River Alyn flood water with knock on flooding into Trevalyn Way and Moss Green with water subsequently crossing Rossett Road into the North Field and Trevalyn Hall View.