Territory Stories

Alice Springs recreational dam hydrology report project 6



Alice Springs recreational dam hydrology report project 6


Jackson, D.; Paige, D.


E-Publications; E-Books; PublicationNT; Report no. 12/1979







Publisher name

Northern Territory Government

Place of publication



Report no. 12/1979

File type



Attribution International 4.0 (CC BY 4.0)

Copyright owner

Northern Territory Government



Parent handle


Citation address


Page content

Technical Report WRD79012 Viewed at 00:02:46 on 18/02/2010 Page 52 of 153. I I I I I I I I I I I I I I I I I I I I 31 6. FLOODING IN ALICE SPRINGS Table 16 shows the expected peak flood discharge at Wills Terrace and Heavitree Gap if the dam is constrqcted. These values are conservative as they assume that the discharges are reduced by the amount of attenuation achieved when the dam is full at the start of the flood. This was done because of the uncertainty of the effect of the Charles River input at Wills Terrace. At floods of high return periods, normally both the Charles River and the Todd River J.ow, so if the flood at the damsite is , reduced by 350 m-/s (50 year return period flood), then it is reasonable to assume that it is reduced by this same amount at Wills Terrace and Heavitree Gap. The peak discharges in Table 16 have been derived using the results of flood routing for spillway arrangement case (a). Table 16 PEAK DISCHARGE AT G.S. 006009 and G.S. 006126 APTER DAM Return Period (yrs) G.S .. 006009 G ~S .. 006126 ----~---" 10 170 3 (m Is) 250 , (m /s) 20 240 (m'/s) 360 , (m /s) 50 380 3 (m /s) 560 3 (m / s) 100 520 3 (m /s) 740 3 em /s) By camparil'S Table 16 with figures 5 and 6, it is seen that the peak discharges are reduced considerably, especially at the lower return periods. The new 100 year return period flood at G.S. 006009 is of the same order of magnitude as the present 20 year return period flood. According to maps included in flood studies of Alice Springs conducted by Cameron McNamara and Partners (1978) and Hug (1979) the present 20 year return period flood will inundate approximately 30 ha of developed land to a shallow depth. The present 50 and 100 year return period floods inundate areas in excess of 200 ha.