Hydrology & Hydraulics

Project: Conder Floodway
Client: Procurement Solutions / ACT Planning and Land Authority
Project Manager: Viet Le

Bill Guy & Partners developed the conceptual design principles around which the project was developed and worked on it right through to its successful completion. The engineers who worked on the development brought to bear a number of initiatives in infrastructure development and water sensitive urban design concepts such as low profile culverts, drop structures and offline ponds and wetlands. The culmination of appropriate engineering designs worked to satisfy the development needs and community concerns.

The project was initiated in order to mitigate existing flooding problems, so the objectives of the project were to satisfy the infrastructure needs for the area as well as providing the neighborhood with an environmental and community asset.This project received a Certificate of Recognition from the Association of Consulting Engineers, Engineering Excellence Award in 2003 and was completed under budget.

The project site is situated next to a grasslands area, therefore careful consideration had to be given to this sensitive site during the development phase and stringent controls put in place during construction. The presence of any development would be keenly felt by residents and numerous community groups. As such, the public consultations undertaken by Bill Guy & Partners were devised to accommodate the interests of the general public and those that coalesced around interest groups. These community groups included: ‘Conder Community Landcare Group’, ‘Friends of Grasslands’ and ACT agencies like ‘Wildlife Research and Monitoring’ and the Commissioner for the Environment.

The development of the Conder ponds and floodway project was an example of a highly successful development undertaken with government and community partnership. Bill Guy & Partners provided both the technical expertise, by way of hydrological engineering services and draughting, and also undertook the community consultation.

Project: East O’Malley Pond
Client: ACT Planning and Land Authority
Project Manager: Viet Le

Bill Guy & Partners undertook the Design Options Study in 2002 to examine the infrastructure required for the proposed land development of East O’Malley Estate adjacent to a high quality nature reserve. The firm was later engaged to undertake detailed design and construction superintendency for the project. Having been engaged by the developer for the design for the land release and the Territory government to design the requisite infrastructure, Bill Guy & Partners was able to utilise the concurrent opportunities to achieve a more advantageous outcome for both clients.

The study had identified that a water pollution control pond/retarding basin was necessary to control pollution exported from the proposed East O’Malley development and to assist in mitigating existing flooding problems in neighboring suburbs. The study also identified the opportunity to enhance and restore the deeply eroded gully adjacent to the proposed development as well as enhance the creek environs and ensure safety for the residents living nearby who may use the area for recreational activities.

As well as having an appreciation of the engineering requirements of the site, members of the project team at Bill Guy & Partners were also able to accommodate a number of other social responsibilities:

• sedimentation core from a heritage dam was collected for research purposes;
• locally collected sees were used for re-vegetation in the restoration phase, and
• in addition to the project improving water quality and flood mitigation, it provided waterholes for surrounding wildlife and a community feature for the adjacent urban development.

Project: Page & Weetangara Stormwater Augmentation
Client: Roads ACT
Project Manager: Viet Le

This project commenced as a feasibility study and review and developed into a detailed design and construction supervision for an upgrade of a major urban stormwater system throughout two established suburbs in the Australian Capital Territory.

The upgrade was sufficiently extensive such that it needed to be broken up into three stages at a total cost of $6 million. The design involved the use of large pipes and reinforced concrete box culverts and drainage structures to convey 100-year ARI events. Engineering design details required that stormwater conduits be laid amongst existing services and mature trees.

 Stage one of the project is complete and the other two stages await funding.

Project: Lake Ginninderra Probable Maximum Flood Protection
Client: ACT Planning and Land Authority in conjunction with Roads ACT
Project Manager: Viet Le

The ACT has an extensive network of artificial lakes and ponds that complement the residential centres of Canberra. Lake Ginninderra is the second largest of the lakes in the ACT; there are also urban developments downstream. Due to this, the dam needs to be protected against failure for up to probable maximum flood (PMF). The problem of having lower dam crest flow was already known and studies during the preceding fifteen years had not been able to economically upgrade the dam.

Bill Guy & Partners was invited by the Territory to undertake a study to revisit the problems involving the dam, such as the inadequacy of the spillway. The project team considered over fifty options for rectifying the problems and was able to propose affordable solutions. The firm was able to make some recommendations such as a minor dam upgrade which has been undertaken, at a cost of $1.2 million, and an upstream retardation basin, which has not yet been implemented. The total costs of the recommendations are estimated at $9 million.