§ Mr. Parrisasked the Secretary of State for the Environment whether he has received the report of the investigation which he set up into the failure during the construction of the embankment dam at Carsington; and what action he proposes to take.
§ Mr. GowI have placed in the Library copies of a first report by Mr. R. E. Coxon, BSc, DIC, FICE, on the failure of the Carsington embankment.
Mr. Coxon's interim conclusions include the following:
The dam failed on the upstream slope before reservoir impounding began. If it had occurred on first filling the water level would have been substantially below the crest at the time and breaching of the bank would have been very improbable.The investigation work on the slide has been both extensive and thorough, carefully and diligently pursued.Testing of materials has been properly performed and monitored; some further testing of samples remains to be completed.The work has provided a sound basis for judgements to be made on the cause and should prove adequate when fully analysed to establish the data on which remedial works can be safely based.Appropriate measures have been taken throughout to safeguard personnel and works, and to leave the site in a secure state for the winter season.The design of remedial works will have to include a number of factors not discussed in detail in this report. These include economics, the effects of proximate ancillary structures and the need to modify or relocate them, the provision for treatment of the foundations in relation to the remedial works proposed, and the geochemical properties of the embankment, foundation and reservoir and their effect on design and water quality.I shall study carefully these and Mr. Coxon's other conclusions. Meanwhile I have the assurance of the chairman of the Severn-Trent water authority that he will consult me before any reconstruction measures are put in hand.
Mr. Coxon expects to present his final report in the Spring of 1985.