Information on the proposed new school Cwmaman
Posted by Lewis on the 19th January 2017
Following on from information AberdareOnline received from a local resident who has concerns regarding the proposed siting and planning application for the new school at Cwmaman.
There are a number of serious questions that require answers, below are part of the text taken from a report “PRELIMINARY GEO-ENVIRONMENTAL AND GEOTECHNICAL REPORT”
Prepared by Earth Science Partnership
33 Cardiff Road
Taff’s Well Cardiff CF15 7RB
Status: Draft Report Document Ref. 5877b.2302 Date: July 2015
The Report was prepared for: Morgan Sindall c/o Bradley Associates 31 Cardiff Road Taff’s Well Cardiff CF15 7RB
The question is has the school site got contaminants as stated in the report, and is this expectable for children and staff?
Below a few extract from reports about the proposed location of the new school, it is up to individuals what they think but if you have any children that will attend the school it would be advisable for you to read the reports in full, also any staff that will be working at the new school.
“Earth Science Partnership ESP.5877b.2302 July 2015 Glynhafod Park, Cwmaman 20"
"2.8.3 Potential Receptors As discussed in Section 1.1, the proposed development will comprise of a single storey junior school. Therefore potential for exposure from any possible contamination, remains in grassed and landscaped areas. The most vulnerable human receptors with regards to any soil contamination present will be staff and pupils of the school. The children’s attendance will be limited and periodic, and the most significant risks are considered to be associated with teachers and caretakers who will have the longest potential exposure to contaminants. Therefore, the school staff (adults) are considered the critical human receptor. The extent of made ground under the site along with the glacial deposits which underlie the Made Ground would suggest a potentially high risk of contamination to controlled waters. With the nature of the glacial deposits which underlie the Made Ground vertical migration of contaminants is a possibility.”
2.8.2 Potential Sources of Hazardous Ground Gas Significant thicknesses of Made Ground are anticipated beneath the site associated with its former industrial uses and the earthworks undertaken to develop the level platform present today. In addition, historical evidence indicates extensive former tips (associated with nearby collieries) are located on the hillsides around the site. There is a significant potential for ground gases associated with the decay of organic and putrescible materials within the waste materials on and off site. There is a potential for localised volatile hydrocarbon gasses associated with contaminated soil beneath existing and historic fuel tanks on-site. In addition, considering the presence of two mine shafts near to the site and probable extensive workings, there is also a potential risk presented by mine gasses. In accordance with CIRIA C665 the sources are considered to be a moderate to high risk gas hazard.
Buildings: · Sulphate attack on buried concrete. · Potential explosive risk from flammable ground gas. Due to the presence of infilled land it is assumed that the site has a high potential for the leaching of contaminants. This will be more prevalent in areas of soft landscaping such as gardens and playing fields, and this may start the leaching of any mobile contaminants present. The fault present across the site could be a major pathway for gases, particularly mine gas, and mobile contaminants.
Ground Gas Risks Prior to development, a programme of ground gas monitoring will be required at the site to characterise the risk posed and the necessary mitigation measures required to be incorporated into the proposed development. A minimum of 6no. visits will be required over a period of 12 weeks. We recommend at least 4no. light percussive boreholes be constructed within targeted areas across the site, to ascertain the ground gas risk. Wells installed as part of the mine working investigation works may be suitable to be utilised as part of the monitoring. Organic material was recorded within the arising’s from TP6 with further potential gas resources coming from the tank and pipeline on the western boundary (see section 2) and from the characteristics of the made ground throughout the site. With the fill overlying the river Aman we cannot discount that organic material associated with the former river bank prior to the culvert being built and the area filled, which could be a source of gas generation. Further trial pits, targeting the specified areas would be required to clarify the extent of the organic material.
The paragraph below taken from the Design and Access Statement
Floor Slab Foundations Due to the presence of over 600mm of Made Ground at the site and the requirement for piled foundations, we consider that ground bearing floor slabs would not be suitable for the development, and floor slabs should be suspended from the piles or incorporated into a raft. Ground gas monitoring has been carried out at the site that has identified elevated levels of hazardous ground gas at the site. It is likely that this would require that the floor slabs be suspended with a suitably dimensioned, vented sub-floor void and a gas resistant membrane. The full results of the gas monitoring regime will be forwarded within an addendum upon completion of the program.
Below part of “PRELIMINARY GEO-ENVIRONMENTAL AND GEOTECHNICAL REPORT”
2.4.4 Hydrogeology Reference to the aquifer maps published on the Environment Agency website (EA, 2013) indicates that the superficial deposits beneath the site (Drift deposits) are classed as unproductive Strata, whilst the bedrock (Middle Coal Measures) are classed as Secondary A. Groundwater movement within the Drift deposits will be controlled by intergranular flow, whilst in the Coal measure bedrock fracture flow is likely to be dominant. Due to the presence of the Cwmneol fault that runs through the site the groundwater levels could be affected. Unproductive Strata are rock layers or drift deposits with low permeability that have negligible significance for water supply or river base flow. Secondary A (generally corresponding with previously classified “minor aquifers”) – permeable layers capable of supporting water at a local rather than strategic scale and in some cases form an important base flow to rivers. The Groundsure Report and the groundwater resource maps on the EA website (EA, 2015) indicate that there are no groundwater abstractions or Source Protection Zones within 750m of the site.
It should be appreciated that in former mining areas, such as this, groundwater conditions may still be changing in response to the cessation or reduction in pumping from underground coal workings (see Section 2.2). A culvert report (Ref: Rhondda Cynon Taff, Borough Council (RCTBC) ref L23350 June 2015) has been provided by the client the salient findings of which are outlined in the following paragraphs: · A manned entry was undertaken by EDS on the 27th May 2015 to identify the horizontal alignment and structural condition of the existing culvert that underlies the area. · A topographic survey supplied in the amendment to the original report suggest that the top of the culvert is approximately 4.0m below the current site level. · It is stated in the report that without further works to the existing infrastructure then it is unlikely that planning permission will accord to current planning/RCTCBC policies regarding flood risk/impact to culverts. An earlier report (Ref: RCTBC February 2010) regarding the history of the culvert was carried out by Land Reclamation and Engineering: · The original culvert that existed in the 1960’s in the vicinity of Fforchaman Colliery was extended by using 8ft diameter concrete pipes. · The Report indicates that flooding at the culvert will occur during a 1 in 100 year period flood event, where the greatest risk to property arises from structures around the River Aman including Glanaman Road, the recreation ground and paddling pool adjacent to the site. Both reports recommend that further work will be necessary if the proposed building is to go ahead. The culvert reports can be found in Appendix H.