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

4. MODEL RE-CALIBRATION It was considered necessary to re-calibrate the model so that the 1957 levels could be consistently reproduced throughout the flood plain. followed was: 4.1 Assessment of Mannings "n" The procedure Gaugings of the Katherine River were analysed to assess the value of mannings "n" for the river channel. Flood plain values were assessed as equivalent to the retardance of grassed waterways,using the methods given by Chow (Chow 1959) Adopted initial roughness/depth relationships for the river and the flood plain are shown in Figure 4.1. 4.2 Cross-section Area Checking The depth-area relationships for all river cell connections were re-calculated, as some were found to be in error at higher levels. Generally there was little change from the original values. 4.3 River Calibration using 1984 Flood The March 1984 flood was selected for initial calibration as it is the largest recorded flood since 1957. This occurred after the 8MEC study was completed. In addition to the GS 814001 record, peak levels were available at Knotts crossing and the low level bridge (the upstream and downstream limits of the model). No flooding occurred on the left bank, and only minor flow on the right bank flood plain. DME2:57