Darwin - Conduct Bathymetric Survey of Darwin River Reservoi

⁠⁠⁠Quotes are being sought to conduct a bathymetric survey of Darwin River Reservoir (DRR). This reservoir is the primary source of drinking water for the Darwin Region.

PWC is refining the models used for annual yield as well as inflow and density currents providing a better understanding of water quality and any changes at low water levels. This modelling will require detailed bathymetry of the reservoir.
DRR is 46 km2, has shallow sides, convoluted bays and a typical mid-lake depth of 17m with depths up to 23m. The reservoir is located 12o 51’ South, 131o 0’ East.
 

The data provided shall have sufficient resolution for a hydrodynamic model mesh to be generated (by the modeller), and be in a readily compatible digital format. Bathymetry should be 50m transect spacing or less, with data points at 5m intervals or less. The model will require increased resolution around the intake tower, dam wall and inflow creeks as well as changes in topography of the reservoir bottom. 10 to 20m transect spacing is required at these locations. There are 6 inflow creeks and around 12 other valleys with relatively minor potential inflow where bathymetry will need to be defined. Relevant GIS files can be provided for some of these features.

Note that small radio or GPS controlled craft may be attacked and damaged by crocodiles and should not be proposed for this project. Personnel should also minimise risk of exposure to crocodiles.

Water surface level is currently 1.9m below full surface level (Nov 2015). Tenderers shall describe their method for capturing ground level data between navigable limit and full surface level and beyond (to tie in with existing/future catchment data). Methods such as boat mounted multi-beam laser and Lidar for both water depth and shore surface measurement will be considered.