Cyngor Bro Morgannwg
Vale of Glamorgan Council

SURFACE WATER DRAINAGE

1. The biggest issue regarding the viability of the site known as ‘Land at Readers Way Rhoose’ (HG1 K53) is surface water drainage. The supporting information the Planning Department has provided for public to comment on, a single drawing by Cambria Number P01, is simply not sufficient. This clearly stated by the drawing itself which is marked preliminary and is not conclusive and open ended.
2. The existing site currently has known surface water drainage issues because of the clay and limestone substrate. During heavy rainwater can be seen running down the surface of the fields and often floods over the boundary in places.
3. Drawing P01 states,” Is indicative of design intention and remains subject to detailed design”. There are no calculations in fact nothing to indicate they have a viable solution.
4. Drawing P01 states, “Soakaway testing unsuccessful – surface water requires positively drainage solution”, this unsurprising given the clay and limestone substrate.
5. Graphically drawing P01 seems to adopt a solution of ‘Attenuation Basins’, the surface water being held there during rainstorms and I assume sent to the two outfalls shown on the drawing with some sort of discharge rate control.
6. Both discharge outfalls are noted as, “Retain and reuse existing offsite surface water connection. Downstream conveyance route requires further investigation”. So currently this is an unknown! This the key to allowing the surface water drainage of this whole site and the number of houses stated left as “Requires further Investigation”.
7. The plan shows pipe connections between the attenuation basins and the outfalls. Four long, large basins along the southern boundary are not shown connected. I assume this is a mistake on the drawing as they will not act as soakaways. In fact, they are the highest risk for the existing houses directly along the southern boundary.
8. The open attenuation basins are shown as 1.5 M deep. When full these will present a significant drowning hazard to local children who will be drawn there as they are not full of water all the time. How is this risk controlled with an open basing design. SuDS principles, “To help create healthy resilient spaces for people …”.
9. An open basin attenuation design my well draw wildlife, but it will also draw rats, midges and mosquitos. As the basins are all located along the existing boundary with existing houses how will this aspect be managed, and should it even be a solution.
10. The LDP talks of up to 520 houses. How could you possibly get to that figure if you do not have a final detailed housing design and in response a fully checked out surface water drainage design. Having carried out these calculations myself you will need the exact area of hard surfaces, roof areas ( so number and size of houses) etc to correctly calculate the attenuation required. Also, fully surveyed outfalls with proved allowable outfall discharge rates. Assume you were just given a number of houses by the developer which is not good enough.
11. With an attenuation design maintenance is critical, without it given the right circumstances the attenuation basins will flood. Note you have referred to a Section 106 agreement. Historically these agreements have not gone well. Who will be responsible for the maintenance of the attenuation basins? If the developer, who will police this and what provisions will be in place if he was to cease trading, as without it we will have a flood situation. Or will it be the local authority and does it have the necessary resource for the long-term commitment. SuDS principles, “considering both construction and long-term maintenance.”
12. What factor of Safety will be built into any drainage design given the existing houses at risk. Currently no detail, how can you expect interested parties to fully comment.
13. The LDP refers to Climate Warming and the anticipated increase in rainfall. What account has the local authority taken of this and what demands have they made on the surface water drainage solution. The basis of the drainage design needs to extend to the life of the proposed development, otherwise in the future the surface water drainage proposal may fail and cause flooding say 10, 20 years on.
14. What allowance has been made when people in the new development start providing hard standings on their front garden. Due allowance for this must be allowed for in the design as this eventuality is uncontrolled.
15. When developing sites, it is a principle that developers should manage and contain potential hazards within their site. In the current proposal the hazard, surface water flooding, has been collected in basins along the southern boundary presenting an increased flood risk to the existing houses along and outside that boundary that did not exist before.

Given all the above it seems inconceivable that this site can be designated as a key Site without the primary hazard of surface water flooding to existing housing being positively resolved. This with at least one fully explored housing layout and compliant drainage solution considering the actual capacity of the two outfalls with full allowance of all the matters raised above.

TRANSPORT

1. The LDP plan clearly shows two access points to the proposed site. The Eastern access is noted as the ‘Primary Access’ and the West to Celtic Way is noted as ‘Secondary Access’. What does this mean? How do you ensure that is the case and that the traffic from the new estate isn’t equally split down both access points and that the Celtic Way access is not actually the ‘Primary Access’. Unless you put controls of some sort in you simply don’t know.
2. Whilst the route down Readers Way is reasonable, (very few houses off the road), and designed for a future estate Celtic Way is not. Some 150 properties are already served on this one estate road, but more importantly there are some 45 houses who must reverse backwards out into the road. This together the many parked cars along the road due to lack of parking provides a significant safety hazard. This hazard will now be increased many times by connecting so many houses down Celtic Way a road which was never designed for this. The transport supplementary information does not deal with this.

INFRASTRUCTURE


1. The LDP refers to developer contribution to the costs of additional school places. The cost of each school place includes a classroom space, teachers, maintenance, etc Has the authority really looked at the real cost of this, and do they really expect the developer to cover that full cost, it would be very surprising if this was the case. The direct result of not providing the full cost of providing the additional school places will inevitably mean stretching things in the existing schools and a drop in what’s available. This the normal story on existing infrastructure in these situations and so this proposal will inevitably impact on the education system in this area. Not great planning.
2. The same situation applies to the doctors and dentists in what is a small village which has seen many developments added in recent years without any additional facilities. There are issues currently accessing both doctors and dentists. What is the planning solution to deal with this issue, it should be in the supporting information for the viability of this key site. This should be identified prior to sites being put on the LDP. To just add sites and refer to Councillors as in some of the recent authority responses is simply not planning.