AS 7637 – Hydrology and Hydraulics

This Standard describes the hydrological and hydraulic functions, performance, design constraints and risk attributes for the design and assessment of railway infrastructure in relation to all forms of drainage in stormwater management.

This Standard is intended to govern public and private railways and railway drainage systems on a whole of life basis and any other drainage related work affecting the rail corridor.

The main purpose of this Standard is to provide a framework that promotes consistency and efficiency in design, construction, commissioning, maintenance, monitoring and decommissioning of track drainage and waterway crossings.

This Standard includes the hydraulic design of surface and sub-surface drainage systems including river and floodway crossings, culverts, pipes, channels, pits and grates.

This Standard aims to provide requirements to support in improving flood event resilience for rail corridor infrastructure. Generally, this involves a combination of flood mitigation, emergency management, flood forecasting and warning measures, land-use planning and infrastructure design.

This product is an Australian Standard focused on railway infrastructure flood management. Its key features include:

• More specific requirements for Railway Infrastructure Managers (RIMs) in infrastructure design.
• Focus on resilience and considerations for future infrastructure developments.
• Potential for considerable safety improvements and cost reductions through improved design and network resilience during flood events.

The standard has undergone significant restructuring with key changes including:

• Removal of content that was considered ‘industry knowledge or textbook’ material for field experts.
• Detailed hydrological design requirements specific for railway infrastructure.
• Consideration of tolerability of existing flood risk, location of existing flood risks, future flood risks, and cultural and social impacts.

The standard delivers improvements through:

• Better infrastructure design leading to greater risk mitigation and resilience in wet weather and flood events.
• Safer overall operations for RIMs and Rolling Stock Operators (RSOs) through effective flood and emergency management plans.
• Reduced social impact due to improved reliability of rail networks, ensuring more consistent transportation of goods.

The standard helps manage several critical risks including:

• Damage to infrastructure due to extreme weather and flood events.
• Damage to assets and rolling stock due to extreme weather and flood events.
• Injury or loss of life due to extreme weather and flood events.
• Environmental impacts due to extreme weather and flood events.

Implementation can occur in several areas:

Design and construction of railway infrastructure:

• RIMs may use this standard to inform the design of future infrastructure projects and when considering upgrades to existing assets.

Existing flood and emergency management plans:

• Review existing protocols against the requirements in this standard and adopt as relevant.
• Create these plans where none currently exist.

Understanding flood risks:

• RIMs may assess and understand existing flood risk and consider if the requirements in this standard may help to control these risks SFAIRP (So Far As Is Reasonably Practicable) within their own organisation.