The physical characteristics of the existing Hams Road Retarding Basin in the Grange Park Estate, and the water surface areas and airspace flood storage volumes proposed for the within 35 Hams Road and 151-229 Anglesea Road are summarized in Tables 1-3. SBRB’s Geotechnical investigations will be required during detail design to confirm lining requirements for the waterbodies and suitability of site soils. It will be important to ensure the wetland base is as watertight as possible to mitigate seepage losses. It will also be essential for any dispersive subsoils to be fully covered with non- dispersive topsoil to mitigate ongoing high turbidity problems. Dispersive soils can normally be retained in base area of the pondages, subject to at least 200 mm of suitable non-dispersive topsoil being spread over the entire area below NTWL. Hence it is important to test both subsoils and site topsoil at the detail design stage to properly assess the threat that may be posed by dispersive soils and the appropriate remedial treatments. Stage-Area-Storage Relations
The physical characteristics of the existing Hams Road Retarding Basin in the Grange Park Estate, and the water surface areas and airspace flood storage volumes proposed for the SBRB’s within 35 Hams Road and 151-229 Anglesea Road are summarized in Tables 1-3. Geotechnical investigations will be required during detail design to confirm lining requirements for the waterbodies and suitability of site soils. It will be important to ensure the wetland base is as watertight as possible to mitigate seepage losses. It will also be essential for any dispersive subsoils to be fully covered with non- dispersive topsoil to mitigate ongoing high turbidity problems. Dispersive soils can normally be retained in base area of the pondages, subject to at least 200 mm of suitable non-dispersive topsoil being spread over the entire area below NTWL. Hence it is important to test both subsoils and site topsoil at the detail design stage to properly assess the threat that may be posed by dispersive soils and the appropriate remedial treatments. Stage-Area-Storage Relations
8d179eb4531e81e-C276%20Surface%20Water%20Management%20Strategy.docx