Surface Water Management Study, DSL Sites

⁠⁠⁠DSL Dampier, Port Hedland and Lake MacLeod operations are regionally and topographically located in areas that are affected by cyclones. Damaging effects to civil infrastructure are incurred as a result of wave overtopping, surface run-off and tidal surge associated with high wind and heavy rainfall events. DSL sites are also frequently impacted by smaller rainfall events, evidenced through impacts to production, as a result of poor field drainage.

Any impact to operations can be reduced or mitigated through building and maintaining the field to withstand selected Annual Exceedance Probabilities (AEP). In order to design for resilience, a quantitative understanding of the business’ risk to various weather events is required. When risk is known, there is an opportunity to operate and address risk more proactively.

In order to address this risk, we require a Surface Water Management Study (Order of Magnitude). This work will feed into the Pre-feasibility Study. Overview of work is as follows;

1. Development of a site drainage model (12D) for the three DSL sites;
2. Development of Hydrology and Hydraulic model (Tuflow) for the three DSL sites;
3. Conduct Risk Assessment workshop with stakeholders. Workshop will cover:

a) Presentation of the findings of the Hydraulic Model in order to document the risks identified and collaboratively determine the risk level, current controls and proposed mitigation options;
b) Identification of critical risk infrastructure to be prioritised for protection by flood mitigation measures ie. infrastructure upgrades;
c) Endorsement of hydrologic design criteria for infrastructure.

4. Assessment (cost, schedule) of various infrastructure upgrades for varying AEP events. Define range of reasonable options for evaluation during Pre-Feasiblity Study.