GUIDELINES FOR THE CONSTRUCTION 
    OF EARTH-FILL DAMS  
         
         
    Water Resources Policy 
    Policy #2008/1 
         
         
         
         
                                           
        November 2008 
                                                   
                          Department of Primary Industries and Water  
         
         
         
  
         
         
         
         
         
         
         
         
         
         
         
         
         
         
         
         
         
         
         
         
         
         
         
         
         
         
         
         
         
         
         
         
        © State of Tasmania 2008 
         
        Water Resources Division  
        Department of Primary Industries and Water 
        GPO Box 44  
        Hobart TAS  7001 
         
         
        Phone: (03) 6233 6753, Fax (03) 6233 6055 
        Email:  water@dpiw.tas.gov.au 
        Home Page:  http://www.dpiw.tas.gov.au/water 
         
        ISBN  978-0-7246-6467-2 
         
         
         
         
         
                      
                      
                     The  Water Management Act 1999 (‘the Act’) provides for the sustainable 
                     management and allocation of Tasmania’s water resources.  Amongst other 
                     things the Act provides for the promotion and fostering of social and economic 
                     benefits from the development of the State’s water resources. 
                      
                     With the commencement of the Act in 2000, a new process for assessing dam 
                     permit applications was established.  Under the Act, a dam permit is generally 
                     required for all dams except in circumstances such as: 
                         •   a dam that is not on a watercourse and that holds less than one 
                             megalitre of water; or  
                         •   a dam constructed for the primary purpose of storing waste as defined 
                             in the Act. 
                      
                     In addition to a barrier across a watercourse, a "dam" includes an excavation 
                     in a watercourse and a flood levee, both of which also require a permit under 
                     the Act. 
                      
                     Under the Act, a statutory committee, the Assessment Committee for Dam 
                     Construction (the Assessment Committee), was established as the body 
                     responsible for assessing applications for the construction of dams. The 
                     Assessment Committee members have expertise in the management of water 
                     resources; the use and economic development of water resources; 
                     engineering and safety matters relating to dams; integrated natural resource 
                     management; and best practice environmental management. 
                      
                     The Guidelines for the Construction of Earth-Fill Dams detail the specifications 
                     for the construction of earth-fill dams, and outline the precautions and 
                     methods which should be employed in order to obtain the soundest possible 
                     structure. These guidelines will provide an overview for dam permit holders 
                     and existing dam owners of the major matters to be considered in the 
                     construction of such dams.   
                      
                      
                      
                      
                     Dr Alan Harradine 
                     General Manager (Water Resources) 
                     Department of Primary Industries and Water 
                      
                     
                    TABLE OF CONTENTS 
                     
                    1.   INTRODUCTION ...................................................................... 1 
                      1.1    Purpose of the Guidelines ................................................................... 1 
                      1.2    Classification of earth-fill dams ........................................................... 1 
                    2.   PLANNING AND MANAGEMENT SPECIFICATIONS ............ 3 
                      2.1    Introduction ......................................................................................... 3 
                      2.2    Risk downstream of a dam ................................................................. 4 
                      2.3    Contract .............................................................................................. 5 
                      2.4    Easements & boundaries .................................................................... 5 
                      2.5    Site investigations ............................................................................... 5 
                      2.6    Filling of the dam ................................................................................ 6 
                      2.7    Dam permit conditions ........................................................................ 6 
                    3.   ENGINEERING AND CONSTRUCTION SPECIFICATIONS .. 7 
                      3.1    Engineering ......................................................................................... 7 
                      3.2    Clearing .............................................................................................. 8 
                      3.3    Foundation* ........................................................................................ 8 
                      3.4    Cut-off trench* or keyway .................................................................... 8 
                      3.5    When to use filters .............................................................................. 8 
                      3.6    Rock .................................................................................................... 9 
                      3.7    Outlet pipe .......................................................................................... 9 
                      3.8    Outlet pipe materials and installation ................................................ 10 
                      3.9    Baffle plates on outlet pipes .............................................................. 10 
                      3.10     Borrow pits ..................................................................................... 11 
                      3.11     Embankment compaction .............................................................. 11 
                      3.12     Compaction testing requirements .................................................. 12 
                      3.13     Batter slope* .................................................................................. 13 
                      3.14     Settlement of the embankment ...................................................... 13 
                      3.15     Vegetation ..................................................................................... 13 
                      3.16     Spillway* or stream return.............................................................. 14 
                      3.17     Freeboard*..................................................................................... 14 
                      3.18     Protection from wave action .......................................................... 15 
                      3.19     Sedimentation ................................................................................ 15 
                      3.20     Maintenance and inspections ........................................................ 15 
                      3.21     Your engineer ................................................................................ 16 
                    4.   ACRONYMS AND DEFINITIONS .......................................... 18 
                      4.1    Acronyms .......................................................................................... 18 
                      4.2    Definitions ......................................................................................... 18 
                    5.   BIBLIOGRAPHY .................................................................... 19 
                     
                     
                    Version          Author               Reason 
                    November 2008  Water      Resources  Policy 2008/#1 released 
                                     Division