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 107 of 153. I I I I I I I I I I I I I I I I I I I I 16 Table 8 ESTIMATED FLOOD FREQUENCY AT DAMSITE Return Period Peak Annual Discharse 3 (years) (m /s) 5 350 10 490 20 650 50 850 100 1000 500 1400 3. 3 unitgraphs using the method of unit graph derivation developed by Ash (1973) two one hour unitgraphs were derived for the Todd River at G.S. 006046 and at G.S. 006009. They are shown in Figure 8. Many of the -recorded hydro graphs were found to be unacceptable for use in the Ash Method because they were either multiple peaked or the peak discharge ~as too small to be regarded as a flood. The method only allows sharply peaked hydro graphs to be considered. At G.S. 006046 the unitgraph was derived from floods on the following dates: 17/4/61, 15/5/63, 13/10/64, 21/1/66, 6/1/76, 2/3/68, 30/12/73, 14/3/77, and 25/11/77. At G.S. 006009 the floods occuring on the fallowing dates were used: 23/2/56, 15/5/63, 25/11/73. 15/12/75, 15/3/77 and 21/11/77. The unitgraph for G.S. 006009 has a longer recession limb and a steeper rising limb. This is partly due to the input from the Charles River. Response time of the Charles River is quicker than the response time of the Todd River and this influences the time of the rising limb at G.S.006009. An average unitgraph (Figure 8) has been developed for input of hydro graphs to the reservoir for examination of flood routing effects of the dam. 3.4 Maximum Probable Flood Estimates of the maximum probable flood have been derived from three sources.