End of Wet Season Stream Flow Measurements, Roper River, May 2014
Kerle, Errol; Waugh, Peter; Northern Territory. Department of Land Resource Management
E-Publications; E-Books; PublicationNT; Aug-14
Early dry season snapshot measurements were taken on the Roper River to establish water quality and quantity conditions at commencement of baseflow conditions. The snapshot measurements are used to: 1. Refine and calibrate the hydrological model used to assess resource availability and allocations. 2. Better define aquifer recharge/discharge zones along the river, and 3. Provide a dataset of comparable flow and water quality measurements at identical periods in the annual water cycle.
Made available via the Publications (Legal Deposit) Act 2004 (NT)
Summary -- Aim -- Introduction -- Observations -- Discussion -- Conclusion -- Recommendations -- References
End of Wet Season Stream Flow Measurement
Northern Territory Government
24 pages : illustrations, colour maps ; 30 cm.
Attribution International 4.0 (CC BY 4.0)
Northern Territory Government
13 Dissolved Oxygen (DO) Typical of groundwater discharge, very low DO was measured at Thermal Springs and on the Little Roper River downstream of Bitter Springs. Significantly higher DO was recorded at site G9030176 (Sat. 117%) indicating that a high level of mixing occurs between the river and the atmosphere. The upper Roper River is fairly broad and flows over several rockbars which forces atmospheric mixing and can dramatically increase DO such as seen in Figure 9. Despite further mixing as the river passes over several more rock bars, DO saturation at G9035294 is significantly lower than further upstream. Further downstream at sites G9030022 and G9030023 DO levels have increased gradually to saturation point at both sites (96% and 101% respectively). DO levels decrease slightly downstream at G9035122 (87%) before returning to saturation levels at site G9030250. Figure 9 Roper River DO Profile May 2014 Environmental DO saturation levels vary significantly throughout the day depending upon water temperature, biological oxygen demand and channel geometry. Excluding direct groundwater discharge sites, measurements made where DO was less than fully saturated were also sites measured prior to 11:00am. Significant aquatic vegetation communities exist throughout the river which actively deplete DO when photosynthesis is not possible, such as overnight. Variations in DO saturation levels between sites are most likely due to time of measurement in the daily DO saturation cycle. Turbidity All sites measured have relatively low turbidity, with the springs having the lowest values. There are no obvious trends across the profile (Figure 9), other than a higher reading at G9035122 probably due to high water velocities at that site. Variations recorded are probably due to site specific causes such as bed material, water depth, water velocity, proximity to rapids or a combination of these.