Safe buffer distances for offstream earth dams

Moore, K. A. and Power, R. K. (2002) Safe buffer distances for offstream earth dams. Australian Journal of Water Resources, 6 (1). pp. 1-15. ISSN 1324-1583


On the Darling Downs in Queensland there is a proliferation of offstream water supply storages (known locally as ring tanks), used mainly for irrigation of broad-acre crops.
Many ring tanks are sited close to public roads for many reasons; the sealed roads provide all-weather access to irrigation areas and particularly waterharvesting pumps but also provide a hard catchment in close proximity to the storage thus improving the frequency of harvestable
overland flows. There are many ring tanks in the district located within 50m of public roads. The question immediately arises of the potential safety hazard to road users in the event of dam failure. In this paper the NWS FLDWAV model was applied to simulate the dam break flood wave for a typical ring tank using a planar surface of varying slope and roughness. The model output was then analysed with regard to vehicle stability to determine a safe buffer distance between the ring tank and road. It was found that the flood wave would produce a subcritical flow on outlet slopes typical of the area for which vehicle stability would be controlled by buoyancy rather than
inertia. The impact of the dam break wave on stability would be reduced by the hydraulic effect of the elevated roadway and through the maintenance of a smooth outlet. A minimum buffer distance of 250m is recommended for smooth, mild outlet slopes in which the flow is impeded by an elevated roadway, increasing to up to 400m depending on the final breach width.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: © Institution of Engineers, Australia 2002
Faculty/School / Institute/Centre: Historic - Faculty of Engineering and Surveying - No Department (Up to 30 Jun 2013)
Faculty/School / Institute/Centre: Historic - Faculty of Engineering and Surveying - No Department (Up to 30 Jun 2013)
Date Deposited: 30 Nov 2007 11:47
Last Modified: 11 Jun 2014 02:21
Uncontrolled Keywords: water storage; tanks; earth dams; tank placement
Fields of Research (2008): 02 Physical Sciences > 0203 Classical Physics > 020303 Fluid Physics
09 Engineering > 0999 Other Engineering > 099901 Agricultural Engineering
07 Agricultural and Veterinary Sciences > 0799 Other Agricultural and Veterinary Sciences > 079901 Agricultural Hydrology (Drainage, Flooding, Irrigation, Quality, etc.)
Fields of Research (2020): 40 ENGINEERING > 4012 Fluid mechanics and thermal engineering > 401207 Fundamental and theoretical fluid dynamics
40 ENGINEERING > 4099 Other engineering > 409901 Agricultural engineering
30 AGRICULTURAL, VETERINARY AND FOOD SCIENCES > 3002 Agriculture, land and farm management > 300201 Agricultural hydrology
Socio-Economic Objectives (2008): E Expanding Knowledge > 97 Expanding Knowledge > 970109 Expanding Knowledge in Engineering

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