Chapter 9: Road drainage and the water environment

M1 JUNCTION 19 IMPROVEMENT
ENVIRONMENTAL STATEMENT VOLUME 2
CHAPTER 9 – ROAD DRAINAGE AND THE WATER ENVIRONMENT
9.1 INTRODUCTION
9.1.1 This chapter is an assessment of the potential environmental effects of the proposed M1
Junction 19 Improvement on road drainage and the water environment. It comprises the
environmental assessment of surface water, groundwater and flood risk during both
construction and operation of the scheme. It includes calculations in line with the Design
Manual for Roads and Bridges (DMRB) Volume 11, Section 3, Part 10, Annex 1. The
chapter also provides recommendations for best practice and mitigation based on the
outcomes of the assessment.
9.1.2 In common with other Chapters, the Road Drainage and the Water Environment
assessment recognises that the Catthorpe Viaduct, which carries the M6 to M1
Southbound link over the M1, is being replaced as a maintenance project. The scope of
this work includes the replacement of the bridge on a new alignment immediately to the
south west of the existing. It also requires the creation of new approach embankments
either side of the M1. The work is programmed to begin in June 2010, for completion in
November 2011.
9.1.3 The bridge and earthworks either side of the M1 would be retained in the proposed layout
for the M1 Junction 19 Improvement, as would the alignment of the M6 to M1 Southbound
link east of the M1. To the west of M1 this link would have to be amended to accommodate
the proposed M6 to A14 link.
9.1.4 A separate environmental assessment 49 has been carried out for the bridge replacement as
a stand alone maintenance project.
9.1.5 This ES for the M1 Junction 19 Improvement takes into account the new bridge both:-
• As part of the existing junction, assuming the M1 Junction 19 Improvement is not built;
the ‘do-minimum’ scenario
• As part of the completed M1 Junction 19 Improvement; the ‘do-something’ scenario.
9.1.6 In terms of road drainage and the water environment, the proposals for the viaduct
replacement will be to match the existing drainage arrangements as far as possible, with
only negligible differences in the locations of pipes and gulleys. There will also be some
reduction in the highway area to be drained as the replacement viaduct will be narrower
than the existing.
9.1.7 These issues are dealt with in Section 9.6 Environmental Impact.
Objectives
9.1.8 The objectives for the road drainage and water environment assessment are:-
• To protect the water environment
• To reduce the risk of pollution and flooding
9.1.9 In addition, there is a general scheme objective that the impact on the natural and built
environment should be minimised. It is also considered that appropriate measures should
be taken and best practice followed during and after construction, by the use of sustainable
drainage techniques.
B0531000_ID_70-EIA Vol 2 Chap 9 Road Drainage and the Water Environment Final Rev 4.doc Page 1