Highways Agency

• M1 Jct 6a to 10 Widening

Environmental Issues

Agriculture and Soil Quality

The proposals would require a total of 88 hectares (21 5 acres) of land of which 81 hectares is currently used as farmland with 29% classed as Grade 2* and 71% as Grade 3’. This loss of land would have a low adverse impact on the majority of farm holdings in the M1 corridor and would be unlikely to threaten the viability of individual farming units

The soils adjacent to the motorway have been analysed for pollutants (lead and other metals, petroleum hydrocarbons, selected herbicides, chlorides and nitrates). Beyond a distance of around 5m away from the carriageway, the soil pollutant levels did not exceed Department of the Environment threshold levels that trigger concern.

Within the 5m distance it is possible that contamination by various metals and petroleum hydrocarbons could potentially exceed the threshold levels. Concentrations of lead and other pollutants reduce rapidly with increasing distance from the motorway.

• Grade 2 soil is used for growing root crops, top fruit, vegetables and cereals.
• Grade 3 soil is used for growing cereals only.

Air Quality

An air quality study has been carried out to determine likely future levels of emissions from vehicles as well as identifying current air quality levels in the vicinity of the M1. Currently, concentrations of carbon monoxide, nitrogen dioxide, petroleum hydrocarbons and lead are at elevated levels at or above the M1 carriageway but they all decrease very rapidly with increasing distance from the motorway.

The most significant of these pollutants is nitrogen dioxide which may exceed EC Directive limits at or above the M1 centreline but not beyond the motorway boundary.

The decrease in vehicle congestion resulting from the widening combined with the introduction of three-way catalyst technology to petrol driven vehicles would result in a decrease in the emissions of both carbon monoxide and total hydrocarbons along this section of the M1.

Nitrogen dioxide levels would also reduce but not as significantly, with levels in 15 years time expected to be broadly similar to current levels despite the expected increase in traffic flows. The overall effect of the scheme would be low to moderately beneficial in the short to medium term. The long term effect would be adverse but of low to negligible significance.

Cultural Heritage

There are 4 known areas of archaeological interest near to the M1 .The most important is the Aubreys, a large banked and ditched enclosure of prehistoric date to the west of the M1 between Junctions 8 and 9 which has Scheduled Ancient Monument status. By careful use of retaining walls, land take alongside this valuable site is minimised and the monument itself would remain unaffected and intact.

There are twelve Grade 2 listed buildings within 200m of the motorway but none of these would be directly affected. Landscaping and/or earth bunding would be designed to reduce the visual impact of the motorway on the designated conservation areas of Flamstead, Potters Crouch and Redbourn.

Drainage and Water Quality

At present, the majority of surface water from the motorway drains into the ground via soakaways, the exception being between Lybury Lane and Coles Lane where the River Ver at Junction 9 provides the outfall.

The new drainage system would put more water into natural water courses wherever possible, with the intention being that the length between Punchbowl Lane and Junction 10 would outfall to the Rivers Ver and Red.

This is in line with the policy of the National Rivers Authority, who have also requested that the use of soakaways in the designated groundwater protection area around Junction 9 is avoided. Pollution control measures such as interceptors or spillage containment trenches would be installed before all run off entry points into ponds.

Ecology

No official or unofficial nature reserves or Sites of Special Scientific Interest are directly affected by the proposed widening. Some 22 sites of varying nature conservation interest have been identified where proposals are likely to have some impact but in most cases the impact would be of negligible importance. Where it has some importance, any losses would be adequately restored over the medium term (5-7 years) by planting to set ecological policies.

The removal of the existing motorway verge vegetation during construction would not be important in ecological terms as little of this vegetation has a significant nature conservation value. The extensive planting regime proposed would reflect local hedgerows both in species and relative proportions where this is appropriate in order to extend habitats for the benefit of wildlife.

Landscape

The landscape through which the M1 passes between Junctions 6A and 10 is pleasant but unexceptional. The main interest is provided by subtle variations in the pattern of woodland and farming. The whole of the M1 corridor is designated a landscape development area and most of the length falls within the Green Belt.

The main effects of the widening proposals on the landscape would result from the loss of the existing vegetation along the motorway verges, changes to the earthworks and the provision of new signing gantries.

An adverse impact would occur during construction with the removal of the existing vegetation, combined with the regrading and enlargement of the side slopes. The screening value of the vegetation removed would be replaced by earth mounding, environmental barriers or new planting. These measures would reduce the impact of exposed sections of the works. The extensive on line planting would provide a screening function, from about the third year after the scheme is opened, improving as the landscaping grows and matures.

The locations of new sign gantries are broadly determined by design standards and safety issues but there is some tolerance in their exact location. The impact of these large structures would be adverse but careful design would allow the screening potential of the adjacent terrain, planting or earthworks to be used to maximise the visual mitigation.

Land use

The proposed scheme does not require the demolition of any buildings or properties.
Around 90% of the land required for the scheme proposals (81 Hectares) is arable land, currently used in the main for combinable crop growth of cereals, or breaks, such as oilseed rape and linseed. Approximately 0.46 Hectares (1.15 acres) of land currently forming part of the Slip End Playing Fields would be required and the remaining areas of land are generally private land not in arable use.

Noise

Comprehensive studies have been undertaken to predict noise levels near the motorway under forecast traffic conditions. Extensive onsite measurements have been made to validate the predictive work and an assessment has been made of the effectiveness of a variety of possible noise mitigation measures.
The resulting noise reduction proposals comprise a combination of earth mounding where sufficient land is available, and/or noise fencing to provide a 3m high barrier alongside the motorway close to residential areas.

These measures would provide an immediate reduction in noise levels at most properties, particularly those close to the motorway. It is estimated that noise levels 15 years after the widening has been completed would generally be no greater than they are at present though a few properties would have a small increase.

Pedestrians and Community Effects

The scheme impact on pedestrians would be negligible with a small benefit in the long term. This impact arises from the proposed alterations to the footpaths which would result in all the existing routes being maintained and at a number of locations a greater separation of the footpath from the motorway being achieved.

There would be no severance effect on the communities near the M1. All existing crossing points would be retained by the scheme and maintained during construction, except for short periods when closures of side roads would be required to ensure the safety of the public.

There would be no significant effects on identified community facilities resulting from the scheme.

Planning Aspects

The impact of the scheme on policy and planning aspects has been assessed by considering the degree to which policy objectives would be managed or hindered by the published scheme. The scheme would be a benefit to Transport, Economic and Road Safety policy objectives.

The proposals have been designed to minimize environmental impacts, especially noise and visual intrusion. Some impacts such as land taken and loss of existing trees and vegetation would mean in the short term an overall adverse effect. The proposed new planting would improve the landscape over the long term as it matures. The scheme would not help Green Belt or Agricultural Policies because of the land required.

Vehicle Travellers

The proposed scheme would have a highly beneficial effect in the short and medium term for users of the motorway and adjacent routes. The provision of increased road capacity would assist in the reduction of congestion this would benefit vehicle travellers by reducing delay, inconvenience and journey times, reducing fuel wastage and transport costs, improving safety conditions and alleviating traffic flows on unsuitable routes adjacent to the motorway.