Hydrology and suspended sediment of the Ngarradj catchment, Northern Territory: 2005-2006 wet season monitoring

Department of the Environment and Water Resources, 2007

Internal Report 521
Moliere DR, Saynor MJ, Evans KG & Smith BL
Supervising Scientist Division

About the report

Ngarradj is a major right bank tributary of Magela Creek, which flows directly into the Magela Creek floodplain. The Jabiluka uranium deposit is located in the catchment of Ngarradj and, therefore, this catchment will be the first to be affected should any impact occur as a result of mining operations at Jabiluka. It is important to determine pre-mining stream conditions within the Ngarradj catchment to be in a position to reliably assess mining-related impacts. Continuous rainfall, runoff and mud concentration data collected at gauging stations on Ngarradj during 2005-06 are presented in this report. The mud concentration data collected upstream and downstream of the mine during 2005-06 were used to establish preliminary trigger values for an event-based Before-After-Control-Impact, paired difference design (BACIP). This comparison of event mud loads observed upstream and downstream of the mine will be used to provide the basis for future impact assessment.