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 57 of 153. I I I I I I I I I I I I I I I I I I I I 35 2.2 Suspended Sediment The arid nature of the Todd Catchment in conjuxtion with grazing as its land use suggests that small diameter suspended sediment transport rates will be high. The measurements of suspended sediment in 1965 and 1979 were both made during climatically extreme periods. The 1965 water year recorded the second lowest rainfall onreGord and was preceded by the third lowest rainfall in 19~5. In addition, 1965 was the last year of a continuous nine year period of below average rainfalls which was the worst drought on record. In contrast the 1979 water year occurs at the end of a seven year period of above average rainfalls and is the wettest per~od on record. Suspended sediment mass flow rates from samples taken at Wills Terrace are plotted against discharge at G.S. 006009 in figure 2. All measurements were 8ade on the falling stage of the hydrograph. No analysis of suspended sediment particle size was made. 2.3 Bed Load One bed load measurement of 650g/8 at a discharge of 10m 2/s was made at G.S. 006009 on 4/3/79. This represents 30% of suspended load or 25% of total load. Estimates of the bed load transport rate at Wills Terrace were made using the Meyer-Peter/Muller formula (Simons and Senturk, 1977). These estimates are sensitive to stream slope values. Stream slopes can be estimated either by assuming a constant Mannings In' value and using Mannings equation for uniform steady flow or by approximating the lbed sloper to the Istream slope 1 . An 'n' value of 0.035 was used in calculating bed load transport at Wills Terrace. Bed load transport estimates made for a cross-section downstream of Wills Terrace using alternative formulae (Cameron McNamara 1978) and the estimates for bed load transport at Wills Terrace are shown in figure 2.