Territory Stories

1985 revision of flood plain mapping - Katherine

Details:

Title

1985 revision of flood plain mapping - Katherine

Creator

Barlow, F. T. H. (Frederick Thomas Harvey)

Collection

E-Publications; E-Books; PublicationNT; 08/86D

Date

1986-02-26

Description

Made available via the Publications (Legal Deposit) Act 2004 (NT).

Notes

Date:1986; Report (Northern Territory. Water Resources Division, Dept of Mines and Energy) ; 8/1986.

Language

English

Subject

Floods -- Northern Territory -- Katherine; Floodplain management -- Northern Territory -- Katherine

Publisher name

Water Resources Division, Dept of Mines and Energy

Place of publication

Darwin

Series

08/86D

Format

various pagings : ill., maps ; 30 cm.

File type

application/pdf.

Copyright owner

Check within Publication or with content Publisher.

Parent handle

https://hdl.handle.net/10070/229366

Citation address

https://hdl.handle.net/10070/673062

Page content

-10 Flows and heights corresponding to the 1 in 100, 1 in 50 and 1 in 20 AEP floods are as follows. Probability 1 in 100 1 in 50 1 in 20 Source Flow m3 /s 5757 4970 3920 G.HT (m) R.L AHD(m) (GS 814001) 19.27 19.10 18.15 105.63 105.46 104.51 Watson et aI, in their 1970 Report, concluded that the 1897 flood was considerably larger than the 1957 flood. Peak stage was estimated to have been 19.37m and peak discharge 6500 m3 /s (their estimate of the 1957 flood peak was 4250 m3 /s). The accuracy of the level would be no more than 300 mm. The high discharge estimate, compared to 1957, was based on the assumption that the railway embankment would have significantly increased the level of the 1957 flood. Experience with the PL2DFlow model (and of other areas where the flood plain is lower than the river banks) suggests that the railway would have little effect on peak river stage. Flood plain flow appeared to be controlled by the level of the river bank levees, not by the railway embankments. A run of the model using the 1957 inflow and with all embankments removed, confirmed this supposition. The level at the gauging station was identical with the level for the as is situation. Levels on the left bank flood plain upstream of the railway were reduced by as much as 650 mm, with an increase in level downstream of about 100 mm. Upstream levels on the right bank were lowered by about 100 mm. It is concluded therefore that the peak discharges of the 1897 and 1957 flood were of similar magnitude. DME2:57


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