Examination of the Welwyn-Hatfield Local Plan 2013-32

Potential sites, for housing development, in villages excluded from the Green Belt that have limited or no proposals for residential development.

Revised Matter 1 Hearing Statement - Site Dig1, East of New Road

Historic , Hearing Statement

March 22nd 2021

Historic England is the principal Government adviser on the historic environment, advising it on planning and listed building consent applications, appeals and other matters generally affecting the historic environment. Historic England is consulted on Local Development Plans under the provisions of the duty to co-operate and provides advice to ensure that legislation and national policy in the National Planning Policy Framework are thereby reflected in local planning policy and practice.

The tests of soundness require that Local Development Plans should be positively prepared, justified, effective and consistent with national policy. Historic England’s representations on the Publication Draft Local Plan are made in the context of the requirements of the National Planning Policy Framework (“the Framework”) in relation to the historic environment as a component of sustainable development.

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Matter 1 - Site Dig1, East of New Road

This site is currently used for agricultural purposes and has no physical features defining its south-eastern boundary, other than the route of a public footpath. The site is within the Green Belt and the potential harm through development, to its purposes, was assessed as moderate in the Stage 3 Green Belt Review. The proposal would develop the site for residential purposes.

Considerations

The site is close to Tewin Water Registered Park and Garden and to viaduct, which is a Grade II* listed structure.

Q1. To what extent would there be harm to these heritage assets? Would it be substantial?

Site Dig1 lies within the setting of several designated heritage assets, including the historic designed landscape at Tewin Water and its associated structures, as well as the Welwyn Railway Viaduct.

Tewin Water is a late 18th-early 19th century landscape park for which landscape designer Humphry Repton produced a Red Book in 1799, with designs making much of the character and qualities of the valley. The contemporary (1797, with later alterations) Tewin Water House, listed at grade II (NHLE: 1055727) along with its associated stable block, lies in the centre of the park towards the bottom of the south-facing slope of the valley and perched above the meandering River Mimram, which Repton dammed and widened to form a long serpentine lake. The house was made a focal point in views across parkland, and there remains a strong visual connection with the low-lying parts of the park south of the River, particularly to the south and south east, and historically to the south west. Despite localised issues, Repton’s design intent remains discernible – indeed, research by the Gardens Trust has highlighted that it is among the best surviving examples of his work within the county. This significance is reflected in Tewin Water’s inclusion in Historic England’s Register of Parks and Gardens of Special Historic Interest at grade II (LEN: 1000920).

While the site lies outside of the registered park and garden so would not result in direct physical impact and alteration of designated heritage asset, it does form part of it’s setting and makes a positive contribution to its significance. The site consists of open countryside rising northwards from the river and overlooks the registered park and garden. There are views of the site from within the registered park and garden, along the entrance road into the park from the west. Development of the site would result in harm to the significance of Tewin Water through change within its setting. Development would overlook the park and intrude into its setting. The access road

2 would probably be provided along the site’s southern boundary immediately next to the registered area and is likely to have a negative impact.

Approx. 700 metres west-north west of the proposed development site, the 30 metre high, mid-19th century Welwyn Railway Viaduct (grade II*; NHLE: 1348122) stretches approx. 475 meters across the River Mimram valley on 40 brick arches maximum height of 100 feet. It is a prominent focal feature within this section of the River Mimram valley, and affords train passengers expansive views up and down the valley.

While this site isn’t as harmful as some, we would prefer other sites to be brought forward first before this one. It remains a less favourable site from our perspective and the site promoter would have to demonstrate that it meets the tests of soundness to be allocated. This includes the impacts on the historic environment.

Therefore, for the reasons set out above, our position remains that we would advise against the allocation of Dig1, particularly when there may be other potentially less harmful alternative sites within .

Q2. Is the harm capable of remediation by appropriate landscaping, with or without earth mounding?

We are not aware that any work has been undertaken to determine the impact of the proposed development on the significance of nearby heritage assets, including Tewin Water and the Welwyn Railway Viaduct. In the absence of this, it is not possible to evaluate what impact development would have on the significance of these assets, and therefore, what if any remediation could be deployed to avoid or mitigate harm as required by national policy. If, notwithstanding our advice above, the Dig1 site were to be considered as a draft allocation, then a Heritage Impact Assessment would be needed to determine the suitability of the site in relation to heritage. This would then inform the design, layout and any mitigation measures necessary to avoid or minimise harm. Without this evidence, we believe that the allocation of Dig1 would be not justified, effective or consistent with national policy.

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