This article is by Dr James Rhodes. It was written in 2005 to inform people about the issues faced by the Park and Ride Development on Patcham Court Farm. The information put forward is from this perspective and not that of the Royal Mail development. It is included here as it is a clear description of what happens on the site and the issues we are trying to fight remain the same.
It is reproduced with Dr Rhodes permission
The aquifer (water bearing rock) at Patcham is within the inner source protection zone, Zone 1. This classification is not an indication that they are ripe for development, but rather a reinforcement of their extreme vulnerability.
Why do we need to protect it? Toxic substances such as hydrocarbons (from oil) are in the list 1 category and should be prevented from entering the potable water supply. Large car parks are a source of such pollutants which leach out during wet weather. Potable water is of a quality suitable for the pot and drinking.
How is statutory protection given? Protection is afforded under EU directive 2000/60/EC, which for example, indicates that relacation of the restrictions for member states is only possible if an overriding need exists and the changes incurred are outweighed by benefits to human health etc. All the conditions set by the directive must be met in full.
In the UK protection is provided by the Environmental Agency which, under matrix 3c of its Policy and Practice for the Protection of Groundwater makes it clear that the removal of water from large car-parks, via a soakaway, into the groundwater system is not acceptable.
What affect would flooding have? Flooding is a major consideration in the Patcham area and the siting of "Park and Ride" there may well lead to serious problems. Flooding can occur in two ways -
(a) A heavy rain or a flash flood situation could occur in which interceptors, designed to separate potable and polluted water may well not function properly. For every cm of rain several hundred cubic metres of water will be generated flooding the A23 and probably bypassed by the interceptors unable to cope wth the volumes involved. This will short circuit the separation process leaving a situation broadly the same as direct discharge.
(b) Water absorbed by the hills will cause the water table to build and, as on numerous occasions in the past, flood the surface. This rising water is difficult to deal with and is unpredictable. It will also short circuit attempts at separation and significantly increase the cost of remedial solutions. Further more the groundwater rising under the impermeable mantle of a carpark, for that is what this would have to be, would find its route to the surface blocked. Presssure would build up and who knows with what ferocity and where it would be released?
Is there a risk from major geological features? It was recorded in 1893 that,during rainfall, water would enter the eastern tunnel, that ran between Braypool and Patcham Court Farm in one day. Polluted water could easily do the same.
This extremely high transmissibility was due to a large fissure, with ready access to the surface which had caused collapse of the tunnel roof. The tunnel network was quite restricted at the time and records show that between 1897 and 1902 t was not unusual for it to be pumped dry. The system was therefore insufficient to meet needs and consequently in around 1927 it was extended. In the process of doing this a major fissure was encountered which virtually doubled the entire yield. These geological features were only found as a consequence of "Mining for water". What other fissures exist and how many they all be affected by the proposal?
What of the future? Brighton and Hove are sinking whereas, quite separately, sea levels are rising. It is likely, therefore, in the course of time, that the more southerly wells will become polluted with salt water. As a result leaving us dependent on the aquifers at places like Patcham. What will we do if, by not protecting them now, they no longer exist? Desalination is a poor substitute for a natural sustainable resource.
Who is reponsible? There seems to be a rush to push the Park and Ride Scheme at all costs so that, before we know it, it's a reality. However, as there are many problems it could become very expensive and Council Tax payers have a right to know who will take responsibility for all of this.
Eur Ing. J. W. Rhodes.
Bsc (Hons), M. Phil., PhD., C. Eng.,C.Math.,C.Phys,