Appraisal Summary Table Jul-19 Name Organisation Highways
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Appraisal Summary Table Date produced: Jul-19 Contact: Name of scheme: A303 Sparkford to Ilchester Dualling Name Description of scheme: The scheme would provide a dual carriageway on the A303 between Sparkford and Podimore in Somerset, connecting the existing dual carriageway sections Organisation Highways England from Sparkford to Ilchester. The scheme follows the existing corridor of the A303 very closely. It is generally considered to be an online solution although is often Role Promoter/Official deliberately aligned just to the side of the existing carriageway to allow re-use of the existing route for local access, avoid property or facilitate construction. At its maximum off-set, the route is typically 100 metres either north or south of the existing A303. Impacts Summary of key impacts Assessment Quantitative Qualitative Monetary Distributional £(NPV) 7-pt scale/ vulnerable grp Business users & transport Journey time benefits by converting old single carriageway section to modern dual carriageway Value of journey time changes(£) providers with associated junction improvements. Net journey time changes is the net of positive and 114.2m negatives in a given time band. Monetary (NPV) includes both journey times and vehicle Net journey time changes (£) N/A 115.4m N/A operating cost impacts. 0 to 2min 2 to 5min > 5min 26.1m 81.3m 6.7m Reliability impact on Business Reliability benefits by converting old single carriageway section to modern dual carriageway with N/A N/A 9m users associated junction improvements. Economy Regeneration N/A N/A N/A N/A Wider Impacts Wider economic benefits by converting old single carriageway section to modern dual N/A N/A 35.3m carriageway with associated junction improvements. Noise Results indicate an overall dis-benefit due to a greater number of households experiencing Households experiencing increased daytime noise in forecast daytime traffic noise increases than decreases, within the calculation area. Mitigation measures year: 128. have been implemented along the alignment and within close proximity to protect nearby Households experiencing reduced daytime noise in forecast residential properties from noise impacts due to the scheme. year: 63. Households experiencing increased night time noise in N/A -0.1m N/A forecast year: 42. Households experiencing reduced night time noise in forecast year: 67. Air Quality Overall there would be a net worsening in local air quality within the study area. The scheme Local Air quality effects at properties (Improvements / No Value of change in would not result in a new exceedance of the NO2 or PM10 annual mean air quality objectives. effect / Deterioration) PM There are no Pollution Climate Mapping (PCM) links which overlap with the scheme's Affected NO2 2023 (1721 / 2964 / 2990) concentrations: Road Network (ARN) in scheme opening year. There are no Air Quality Management Areas PM10 2023 (284 / 5702 / 1689) NPV: -0.07m (AQMAs) within the scheme ARN in the opening year. The regional assessment predicts an increase in emissions of NOx and PM10 primarily as a result of an increase in the number of Overall Assessment Score (negative score reflect benefit) Value of change in vehicles travelling on the A303. Overall, the total change in NPV is negative indicating a net NO2: (2023): 52.21 NOx emissions: worsening in air quality when considering both local and regional effects. PM10: (2023): 19.30 N/A NPV: -0.29m N/A Change in Regional Emissions Total value of NOx (2023): 12.6 t/year change in air PM10 (2023): 1.2 t/year quality NPV: - 0.36m Greenhouse gases The scheme is estimated to cause an increase of 625,195tCO2e in non-traded emissions and Change in non-traded carbon over 60y (CO2e) 625,195t increase by 5,972tCO2e in traded emissions over 60 years. The increase in greenhouse gases (GHGs) has been caused by an increase in the vehicles using the new road, and therefore more vehicle kilometres are travelled between the opening year of 2023 and the forecast year of 2038 N/A -27.9m Change in traded carbon over 60y (CO2e) 5,972t as well as an increase between the Do-Minimum (DM) and Do-Something (DS). Landscape The proposed scheme is set within the Yeovil Scarplands National Character Area (NCA), characterised by its remote rural nature, steep Scarplands, broad ridges, and the pattern characterised by historic Roman and Neolithic settlements, medieval open field patterns, manor houses with surrounding parklands. The proposed route would be either online or very close to the existing A303 route corridor, minimising impacts upon landscape character and nearby visual receptors. The expansion to dual carriageway would however be at odds with the local landscape pattern and scale. There would be a direct impact upon the designated Hazlegrove House Registered Park and Garden (RPG) and the scheme would also be in proximity to Conservation Areas at West Camel and Queen Camel, however they would not be directly affected by the N/A Slight Adverse N/A scheme. This scheme would be visible from local visual receptors including residential properties and Public Rights of Way, however views would be limited in some areas where the route would pass in cutting, aiding its visual integration, and limiting views of associated traffic in some areas. Proposed mitigation would include the construction of bunds to create false cuttings and replacement planting. Whilst this mitigation would aid the scheme's integration, the route would not quite fit the landform and scale of the landscape. The overall effect on landscape would be Slight Adverse with mitigation in place. Townscape The scheme runs through a rural environment and therefore just landscape has been assessed for this scheme. The built environment is limited to small-scale settlements which are not directly N/A N/A N/A Environmental impacts by the scheme and therefore it is considered there would be limited value in undertaking a townscape assessment. Historic Environment The proposed scheme would require large areas of medium value unknown archaeological buried remains to be excavated during construction, resulting in potential damage. Agricultural earthwork remains within the proposed scheme boundary would be fully removed by the scheme, however these are considered of low value. Archaeological remains would be evaluated and, where necessary, recorded and excavated. The scheme would pass through the southern section of Hazlegrove House Registered Park and Garden (RPG), which would result in the removal of elements of the historic parkland. The junction is condensed towards the woodland Moderate and arable fields in the south western corner of the park to reduce the land take and impact on N/A N/A Adverse the historic parkland. Archaeological monitoring of the remains of the driveways would be undertaken. Replacement planting to would aid the screening of the scheme from heritage assets, as well as screening the existing services at Camel Hill from the house. The scheme would result in a Moderate Adverse effect with mitigation and therefore an overall worsening of the historic environment. Biodiversity The scheme is located adjacent to Camel Hill Transmitter Site Local Wildlife Site (LWS) and Gason Lane Field LWS and within Hazlegrove Park LWS. Small scale direct loss of broad- leaved woodland, parkland, calcareous grassland and hedgerows is anticipated as a result of the scheme. These are listed as Priority Habitats. Wildlife using these habitats such as bats, breeding birds, barn owls, reptiles, great crested newts and badger are likely to be subject to increased disturbance and loss of habitat. The loss of any habitat of conservation value would be N/A Slight Adverse N/A replaced like-for-like as a minimum requirement. New planting would be connected to existing habitat within the landscape to compensate for the loss of wildlife corridors and reduce the fragmentation impact of the scheme. The overall effect on biodiversity would be Slight Adverse with mitigation in place. Water Environment The principle receptors include the River Cam - Lower and the River Yeo downstream of Overcompton to the south and the River Cary - Source to confluence with King's Sedgemoor Drain (KSD) to the north-west, both of which are Water Framework Directive (WFD) waterbodies. In addition, Dyke Brook runs to the north and Park Brook to the north west. The scheme would be unlikely to affect waterbodies during the construction phase as works would include standard mitigation measures. The scheme would also be unlikely to affect waterbodies once operational as Sustainable Drainage Systems (SuDS) and pollution control measures have been incorporated in the drainage design. These measures would prevent adverse effects from pollutants / contaminants / excess sediments from routine runoff (or from accidental spillage N/A Neutral N/A incidents) during operation reaching the downstream waterbodies. Some parts of drainage ditches and ponds would be lost as they would be infilled to accommodate the new carriageway. New drainage ditches and ponds would be created to compensate for any losses. The scheme would be located within Flood Zone 1 and would not affect / or be affected by areas within Flood Zones 3 and 2. The overall impact on the water environment would be Neutral with mitigation in place. Commuting and Other users Journey time benefits by converting old single carriageway section to modern dual carriageway Value of journey time changes(£) 74.9m with associated junction improvements. Net journey time changes is the net of positives and Net journey time changes (£) N/A 31.7m Moderate beneficial negatives in a given time band. Monetary (NPV) includes both journey times and vehicle 0 to 2min 2 to 5min > 5min operating cost impacts. 6.9m 63.3m 4.8m Reliability impact on Reliability benefits by converting old single carriageway section to modern dual carriageway with N/A N/A Commuting and Other users associated junction improvements.