Alice Springs recreational dam hydrology report project 6
Jackson, D.; Paige, D.
E-Publications; E-Books; PublicationNT; Report no. 12/1979
1979-10-01
Date:1979-10
English
Northern Territory Government
Darwin
Report no. 12/1979
application/pdf
Attribution International 4.0 (CC BY 4.0)
Northern Territory Government
https://creativecommons.org/licenses/by/4.0/
https://hdl.handle.net/10070/228346
https://hdl.handle.net/10070/674275
Technical Report WRD79012 Viewed at 00:02:46 on 18/02/2010 Page 148 of 153. I I I I I I I I I I I I I I I I I I I I 45 The 40 year life of the reservoir under high suspended load conditions stresses the necessity for management of catchment land use, especially in drought periods. The present reconstruction of the Stuart Highway through the catchment may also lead to similar high sediment conditions. Care should be taken in construction to preserve natural slopes and vegetation and to prevent erosion of road embankments. 3.5 Sediment Trap In order to alleviate the effect of bed load on the dam a sediment trap was considered. A suitable site exists immediately upstream of the reservoir where the two arms of the Todd River diverge, (figure A). It is approximately 50m wide, 700m long and 3m high. Table 8 shows trap efficiencies for different sand particle sizes and peak inflow rates at the sediment trap. The results show that the sediment trap will retain most of the sand fractions down to the FSa The trap efficiency for the FSa and VFSa fractions can be improved by increasing the surface area of the sand trap to minimise overflow velocities. Table 8 TRAP EFFICIENCIES FOR DIFFERENT PARTICLE SIZES AND PEAK INFOR RATES - SEDIMENT TRAP (PERCENT). Return Period Peak Trap Efficiencies % (Years) In flow VCSa CSa MSa FSa VFSa Rate (Jn3/ s ) 5 350 100 100 100 100 65 10 490 100 100 100 100 46 20 650 100 100 100 100 35 50 850 100 100 100 82 27 100 1000 100 100 100 70 23 500 1400 100 100 100 50 16