Protection of Inland Elevated Slopes and Areas from Landslips and Weakening Soil Conditions
Ministry of National DevelopmentSpeakers
Summary
This question concerns Ms Ng Ling Ling’s inquiry regarding systematic efforts to identify and fortify inland elevated slopes against risks of landslips and sinkholes. Minister for National Development Desmond Lee explained that public agencies conduct regular slope inspections, with NParks increasing frequency during wet weather, to implement necessary mitigation measures. He highlighted that the Building and Construction Authority (BCA) requires Qualified Persons to assess risks and recommend stabilising structures before construction begins on slopes. Additionally, BCA issues maintenance advisories to landowners and mandates site investigations and ground movement monitoring for underground works to prevent sinkhole occurrences. These policies ensure slopes remain stable under extreme rainfall while builders implement additional safety measures during excavation projects to protect public safety.
Transcript
43 Ms Ng Ling Ling asked the Minister for National Development besides defending Singapore's shoreline against rising sea waters with a coastal defence plan, whether there will be similar efforts for the inland elevated slopes and areas with gradients to systematically identify areas where there can be risks of landslips and sinkholes and to fortify against weakening soil conditions.
Mr Desmond Lee: Agencies that manage public land carry out regular inspections on slopes that may pose a risk to public safety and implement appropriate mitigation measures to stabilise the slopes if required. For example, NParks inspects slopes in parks and gardens on a quarterly basis during fair weather and on a weekly or monthly basis during periods of intense wet weather.
In addition, BCA requires all slopes that are formed as a result of building works to be assessed for risk of failure by a Qualified Person (QP) before construction commences. The QP is required to recommend slope protection measures to be put in place, such as earth retaining walls and stabilising structures, to ensure that the slope remains stable under adverse weather conditions, including extreme rainfall.
BCA also issues regular advisories to remind land and building owners to implement measures to manage the risk of landslips for their slopes. These include ensuring adequate drainage and proper maintenance of slope- and earth-retaining structures.
Sinkholes in Singapore are generally caused by larger scale excavation or underground works. For such works, BCA requires a QP to conduct a site investigation and recommend measures to prevent sinkholes from occurring. BCA also requires the builder and the QP supervising the works to monitor ground and building movements during construction, and to implement additional safety measures as necessary.