London Gateway Port

Abstract

HR Wallingford were commissioned by London Gateway to advise on marine and coastal processes and in particular are responsible for the modelling of the impacts of the marine works to enable an understanding of impact to be developed. They have been involved in the project since 2001. The modelling, analysis and interpretation described in this report is based on the methodologies originally employed in the hydraulic studies undertaken to support the EIA. The physical impacts of the two refined scenarios "interim" and "final" have been assessed and contrasted with the "original" scenario as assessed in the EIA. The main findings are as follows: * At an estuary wide scale, no significant changes to predictions of impact on upstream tidal propagation or extent of impact of the works as a result of scheme refinements. * Minor changes to flow regime compared to original scheme. * Siltation on Mucking Flats less than for original scheme * Maintenance (mud deposition) in the original scenario was 1.7 Mm3/year: - initial refined scenario is predicted to be 2.0 Mm3/year - final refined scenario is predicted to be 1.3 Mm3/year * In neither scenario would there need to be a change to the approach to future maintenance dredging requirements as outlined in the EIA. * Maintenance (mud deposition) at nearby berths for both refined schemes is predicted to be similar to that predicted for the original scheme. It can be inferredd from these results that if the interim scheme were modified to a scenario where three container berths had been built, there would be no further change to the flow regime at the adjacent downstream berth.