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ROADS (SCOTLAND) ACT 1984; ACQUISITION OF LAND (AUTHORISATION PROCEDURE)(SCOTLAND) ACT 1947
M74 SPECIAL ROAD (FULLARTON ROAD TO WEST OF KINGSTON BRIDGE) ORDERS
REPORT OF PUBLIC LOCAL INQUIRY INTO OBJECTIONS
VOLUME 1 : MAIN REPORT

CHAPTER 7 : GEO-TECHNICAL, MINING & CONTAMINATED LAND

The Approach

7.1 The TRA evidence was based on a Ground Investigation (the GI) involving a number of consultants and liaison throughout with the design team on the planning and design of both the investigation and the emerging detailed design and route of the M74C. The details of the GI and the results are contained in chapter 7 and Technical Annex C of the ES (TRA/F/1) and Productions TRA/I/1 - TRA/I/4. The GI is an ongoing process.

7.2 The GI itself was based on desk top studies reviewing all available information, the study on contamination and mitigation measures culminating in the production of an Inception Report (TRA/I/1), indicating the results of the research and the areas where further site investigations would be necessary. For the purposes of the GI, the route was divided into 5 sections, with a further 29 discrete sub-area sites identified as major historical industrial land use sites, where contamination might be expected. As regards geology, widespread areas of thick deposits of alluvial soils and shallow mine workings were noted, along with some local areas of deep fill deposits. The exact position and condition of mineshafts required to be determined. Following these preliminary studies, a contract for the GI was drawn up and let.

7.3 The main GI, which was undertaken between August and December 2002, included 304 light cable percussive boreholes (including 36 rotary cored holes), 250 trial pits, 58 static cone penetration tests, and 24 window sample holes. A number of groundwater sampling points and 62 trial trenches were included, along with a considerable number of in situ tests.

7.4 Analyses carried out by specialist personnel assessed the impact of the ground conditions along the route, including the potential risk of collapse to mineshafts and mine workings and the impact of such failures on the surface. Assessments of the settlement characteristics of the fill and alluvial soils under varying load conditions of embankments were made, and the analyses helped to formulate recommendations for the design and construction of the road.

Geo-technical & Mining Issues

7.5 The general geological findings of the investigations showed that the proposed route was along a line largely within the Clyde basin. Fill deposits were widespread and generally less than 5m thick, except for deeper wastes in former clay pits, followed by alluvium. These thick alluvial deposits (mostly over 20m) generally consisted of clays, silts and sands, often laminated and inter-bedded and generally grading coarser with depth. The alluvium was followed in places by glacial till, or rockhead, at depths ranging generally between 20 - 40m. Three separate groundwater systems were identified. While artesian conditions were known to exist in the Cambuslang area, the investigations found this not to be the case at the route location in that area.

7.6 Shallow mine workings were identified at several locations along the route, specifically at Gushetfaulds (chainage 1,580) to Dixon Blazes (chainage 3,500) and West Clyde Approach (chainage 6,700) to Fullarton Interchange (chainage 7,780). The workings were found to include the stoop and room and longwall methods of mining. Potential instability was identified at several locations along the route.

7.7 The fill was found to be mainly of general composition, except for the locations of back filled clay pits around the Rutherglen area, where chromium waste was found, and at the former Clydebridge Steelworks, where paper pulp waste and some slag material were encountered.

7.8 The concept design was for the road to be retained at an elevated level to aid crossings and maintain the route above contaminated ground. This necessitated the incorporation of several embankments and viaducts. For areas where high embankments were indicated, considerations of settlement under the imposed loading of substantial soil cover were required.

7.9 Construction techniques considered included pre-loading and surcharging of the embankment footprint, the use of lightweight fills, stage construction, accelerated settlement techniques incorporating soil drainage, basal reinforcement to the embankments, and piling. All structures would require piling. Foundation options for embankments and structures were based on minimum disturbance to contamination. Piled embankments were recommended at 5 locations, particularly in the areas of deep wastes. Elsewhere, basal reinforced embankments were recommended..

7.10 Grouting was recommended for sections of the route underlain by shallow mine workings with a potential for some collapse and surface subsidence. This would involve drilling into the mine workings and using the drilled holes to insert a cement grout for infilling. Several mineshafts in sections of the route were recommended for grouting and capping. Approximately 1.7 million cubic metres of fill may be required for the construction of embankments. Possible sources of the fill material were suggested.

7.11 As regards costs, earthworks were estimated at £30 million, piling at £13.5 million, and stabilisation works at £8.3 million. There was nothing abnormal or exceptional in either the works or costs anticipated, the works being standard and conventional activities associated with a road project.

Ground contamination

7.12 The contamination studies, recorded in the documents described above, followed the guidance in the DMRB and PAN33 (TRA/I/1).

7.13 Historical maps and photographs indicate extensive tracts of the proposed route were previously occupied by heavy industry, including iron and steel, chemical and paper manufacturing, collieries and clay pits, and associated railway land, giving the potential for significant land and groundwater contamination.

7.14 Current ground conditions typically comprise a universal layer of made ground of varying but substantial thickness, overlying the alluvial infill of the Clyde valley. Groundwater is present within each strata type, but the vertical movement between different strata is limited. Shallow groundwater flow directions are generally controlled by topography and the location of the nearest surface watercourses. The GI included sampling of soils and groundwater from boreholes and trial pits in over 500 locations, as well as the sampling of surface waters and soil gases. Monitoring wells were installed at 261 locations to allow continued monitoring of groundwater and soil gas.

7.15 Relevant contaminated land legislation includes the Control of Pollution Act 1974, the Environmental Protection Act 1990, and the Environment Act 1995, including Part 11A and subsequent regulations, planning legislation, and the Health and Safety at Work Act 1974. Key future legislative drivers include the Water Framework Directive and the Environmental Liabilities Directive. Contamination and pollution identified along the route do not fall within any single aspect of the legislative framework. Most of the contamination is defined as "historical" in that the primary cause of the contamination happened in the past. A key feature of the new contaminated land regime and guidance is that the land should be "suitable for its current use". Changes of land use trigger controls through the planning process to ensure that the change of use will not lead to environmental damage. Where a development is subject to planning permission, the planning legislation is primary and the Part 11A secondary. Where land is not subject to planning controls, the default position is Part 11A. This is the situation for the M74C. Local authorities are the primary regulators for both planning and the new contaminated land regime, and liaison with the relevant local authorities is ongoing. The contaminated nature of the route means that compliance with the provisions of the Health and Safety at Work and Control of Pollution Acts will place significant constraints on construction work procedures.

7.16 Assessment of contamination within the corridor conformed to established current best practice, using a risk based approach on a site by site basis. Data for each site was gathered from documented information and used to create a conceptual model covering the entire route. The risk assessment approach involved identification of hazards, receptors and pathways (between hazards and receptors) for each site to determine significant pollution linkages that may result in measurable impacts on specified receptors. Possible linkages were identified, enabling impacts in terms of both likelihood and magnitude to be predicted. SEPA, the relevant departments of GCC and SLC, and the design team were consulted throughout.

7.17 Contaminants of concern identified included chromium waste, paper manufacturing sludge, steelworks slag, combustion residues, and made ground arising from general re-grading of previous development. Areas of chromium waste, chemical waste, and slag tend to exhibit the highest levels of contamination. Other sources of contamination include surface spills and fly tipped waste. Asbestos was reported at the majority of sub-area sites along the route. Chromium waste was identified on that section of the route from Dixon Blazes Industrial Estate through Rutherglen and Cambuslang.

7.18 The receptors at significant risk were identified as: -

7.19 The remedial approach to the contamination was one of integration and iteration, the effects of the contamination being incorporated into the design process and resolved to the point where no unacceptable impacts are anticipated. The strategy adopted involved above ground construction wherever possible to minimise disturbance of contaminated materials, identification of regulatory constraints, adoption of compatible remedial solutions, and a review of all aspects of road design from a contamination viewpoint to allow for modifications as appropriate.

7.20 Final remedial options for the M74C, in general terms, include selective removal of discrete sources of contamination; prevention of any direct contact with contaminated soils by way of placement of engineered structures across the entire route corridor; restriction of infiltration of water into contaminated soils beneath the route; in situ treatment of contaminated soil and groundwater where contaminated soils are to be significantly disturbed by the construction process; interception of contaminated water by in situ treatment facilities, where contaminated made ground is present below normal groundwater levels; engineered protection of culverted surface waters; specification of appropriate building materials; and protection of buried services. In addition, the whole construction and operation of the road will be subject to an Environmental Management System (EMS), acting as the primary mechanism for delivering the required protection of construction and maintenance workers and the public. Contract conditions will regulate hours of working on the various activities in both the construction and operational phases, thereby minimising the impact on residential amenity.

7.21 Remedial options include well established and proven techniques. While the approach does not remove contamination, it does offer positive benefits such as minimal disturbance of contaminated materials and compatibility with the road structure and construction process. Removal can pose greater risks than bunding of contaminants. Unfortunately, bio-remediation cannot deal with the concentrated inorganic based contamination that is prevalent along the route. As regards the retention or disturbance of chromium waste residues, the affected areas have been identified and procedures developed to manage contact with the contaminated materials and prevent hazardous releases, both during construction and when the road is operational. In some areas, exposure of contamination will be necessary to allow adequate treatment to take place, but most of the road will be built without disturbing the existing contaminated material.

7.22 The M74C can be constructed in a manner that will manage the contamination impacts throughout the construction period, and planned remediation measures will mitigate long term environmental risk. Without the M74C, much of the route and adjacent sites are likely to remain in their present contaminated condition.

The Case for JAM74/FOE

7.23 No counter evidence was led by JAM74/FOE on geo-technical, mining and contamination issues and there was no cross-examination of the TRA geo-technical and mining witness. The contamination evidence, however, was the subject of extensive cross-examination, particularly in relation to the extent and nature of the contamination, the proposal to bury much of the contamination (particularly chromium waste) under the M74C itself rather than removing the contamination completely from the areas affected; the extensive earth and piling works involved and the associated noise and disturbance; the limitation of the GI to the route corridor itself, leaving the adjacent regeneration sites for treatment in due course by potential developers; and the massive costs involved in remediation works.

The Case for SAPT

7.24 Again, SAPT led no counter evidence and there was no cross-examination of the TRA geo-technical and mining witness. Cross-examination of the contamination witness focussed on the possibility of a break in the linkage between a source and a receptor; the statutory responsibilities of local authorities to deal with contaminated land; and the suggestion that containment of contamination as opposed to removal was driven by cost considerations. The cost of the SAPT alternative proposals involving tunnels at West Street and under Rutherglen Station was also raised in the cross-examination of Brian Swan, who indicated that contamination problems were likely to be encountered. While no detailed study had been carried out, costs were likely to be of the order of £100/115 million at West Street and £30/50 million at Rutherglen, with further costs of £65/80 million on the section between Farmeloan Road and Glasgow Road.

The Case for Mr T Martin

7.25 The objector is particularly concerned about the proposal to construct the M74C through areas such as Southcroft Park at Glasgow Road, Rutherglen, which is known to be severely contaminated with hexavalent chromium waste, a known carcinogen causing nasal, skin and lung cancer if ingested. Previous sites of a similar nature in Rutherglen have simply been capped over and left undisturbed on advice from the relevant authorities that the waste was too dangerous to move and disturb. Old mine workings also lie beneath Southcroft Park and previous expert reports have highlighted the dangers of piling and laying foundations on such unstable materials. The M74C is to be a Design and Build contract and accordingly the design has not been finalised. The environmental assessment has proceeded on the basis of assumptions.

The Case for Terrace Community Association

7.26 The objection is a general one, highlighting concerns at the high levels of chromium waste in the Rutherglen area and the risks to health which construction of the M74C on the line proposed might bring. The suggestion of re-routing the road to the north to an earlier line involving 2 bridges at the Cuningar Loop is suggested.

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