Vietnam: Requirements for surface water discharge systems in construction planning

Requirements for surface water discharge systems in construction planning in Vietnam are stipulated in Section 2.8.2, National Technical Regulation QCVN 01:2021/BXD on Construction Planning issued with Circular 01/2021/TT-BXD. To be specific:

- Planning for surface water discharge system must: ensure capacity and volume of detention basin system for regulating surface water; utilize basin areas to temporarily store rainwater; increase coverage of water-absorbent surfaces for traffic structures, yards, technical infrastructure, and other public areas. Available urban areas must retain, renovate, and upgrade current lakes, rivers, and canals to ensure adequate volume for storing and circulating surface water;

- Planning for surface water discharge systems at new development areas in Vietnam must not affect the ability to discharge surface water of available areas;

- Planning for surface water discharge system in Vietnam must include minimizing impact of natural disasters (inundation, flood, typhoon, high tide, landslide, etc.), and responding to climate change and rising sea level;

- Newly constructed areas must install separate water drainage system. Areas installed with general water drainage system must upgrade into semi-separate water drainage systems or separate water drainage systems;

- Surface water discharge system must be calculated based on frequency of rain that overflows the sewers. Minimum frequency of rain that overflows the sewers is specified under Schedule 2.14;

- Requirements for collecting rainwater: rainwater discharge system must be installed on every inner urban road and road leading through residential areas in the outskirts;

- In addition, structures within water discharge network must conform to QCVN 07-2:2016/BXD.

Schedule 2.14: Minimum frequency of rain that overflows sewers (year)

Sincerely.