Water Environment:
Model Development

1. The baseline (existing) model has been fully transferred into InfoWorks ICM, form the original strategy to undertake the work in HEC-RAS.
2. The model is run with an upstream flood hydrograph, and direct rainfall runoff on the modelled Loxwood catchment. The model should therefore be the best combination of a fluivial model (like the EA Flood Risk from Rivers mapping) and a pluvial model (like the EA Flood Risk form Surface Water).
3. The updated model is therefore able to replicate the overland surface water flooding of Burley Close.
4. The baseline model is still being improved to include the additional detail including headwalls, private garden walls and surfacing which may affect known property flooding.

 
Initial Assessment of Potential Options

1. Formal option modelling will only be undertaken once the baseline model is fully complete.
2. The model does show floodwater backing up upstream of the Guildford Road culvert, however opening up this culvert in isolation would likely increase flood water levels downstream at Pond Close and Oak Grove.
3. At Oak Grove, the model suggests that there the second twin culverted private crossing to no.6 Oak Grove (which was previously flooding) is an obstruction to flow, as water levels differ by 0.5m either sides of the culverts. One of the two pipe openings is half blocked, so and easy option would be to clear both culverts. The second option would be to remove the existing brick side walls and replace with railings. The replacement of the brick bridge side walls could also be done to the upstream twin culvert crossing to No. 5 Oak Grove. A further option could consider replacing both twin pipe culvert crossings with free span bridges or alternatively a larger box type opening.
4. Improving the drainage through Oak Grove unlikely to negatively impact houses downstream, with the exception of the properties at Burley Close.
5. The model will consider the benefit of opening up the culvert beneath Station Road, however a low flood defence barrier along the back of the properties at Burley Close may be necessary to reduce flood risk. The issue with a formal flood defence is that it may then also block surface water runoff from entering the river, creating additional flooding at Burley Close. The benefit of the latest update to the model is that this can be tested.
6. The model suggests that the source of the overland surface water flooding of Burley Close is from the uphill residential plots, rather than primarily from runoff from the school surfacing. Surface water seen coming through the school fencing, while including some contribution from the school surfacing, is from offsite runoff onto the school site. There may be some options which could be worked with the school to assist in better directing / converting overland flow to the river.

The Parish Council are still awaiting the results of the surveys carried out along the stream through Loxwood in March. The Consultants "Water Environment" have promised an update for the Parish Council meeting on 9th September 2019. Please come along to hear the latest.

The Parish Council's Flooding Consultants are working on the data gathered from the hydraulic surveying of the Lox Stream. Once the reports are available a public meeting will be held to publish the suggestions for flood mitigation from the Consultants.

​Loxwood Parish council has secured funding of £25,725 which is the full cost of our environmental consultant and a surveyor carrying out the modelling and hydraulic testing that is required to establish the best means of mitigating flood alleviation to the most residents in Loxwood. The Consultants have been given the go ahead to carry out this work and a meeting of the Flood Forum will be held once the results are known.

​The Stream walk has gone ahead and informed quotes for hydraulic modelling and surveys to be carried out to produce a plan for mitigation measures. These quotes are currently with Operation Watershed for a funding assessment. November 2018

Lox Stream Walk.
​ This is to take place on Wednesday 26th September 2018. Parish Councillors and our Water Environment Consultant will be walking the route of the Lox Stream. This is to inform on any remedial matters that can be achieved to mitigate flooding in the area of the stream.

Following on from the decision by the Environment Agency to not carry out any mitigation for Loxwood of its flooding problem as a result of not being able to obtain funding from Central Government, the Parish Council have met and agreed a course of action with an Environment Consultant.
Various topographical surveys and hydraulic models are going to be work upon to establish the best method of reducing the likelihood of flooding. In addition the Parish Council have sent out a questionnaire to the areas that have in the past been affected by flooding to establish actual facts to be used by the Consultant in his modelling.
​The Parish Council urge all whose garden the Lox Stream runs through to clear thoroughly their ditches and waterways and this speeds the passage of water along the stream at times of heavy rainfall. Ornamental obstructions and fencing across your section of the waterway could be the cause of someone else’s misery from flooding.

The Parish Council met on 23rd February with Water Environment Consultancy to discuss measures that can be taken by the Parish Council to mitigate(although not prevent) flooding in Loxwood.
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Following the Environmental Agencies advice to the group that their investigations into the Loxwood flood problem had arrived at the conclusion that Loxwood would not qualify for central government funding, the Parish Council have taken matters into their hands. They have met with the EA and WSCC and are inviting the Consultants Water Environment to carry out further modelling of the situation to establish whether ideas they have will help provide security for those affected by flooding. They have also established a plan of action of local activities that can be carried out to help the situation and the Parish Council will be writing to those residents affected.
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