SUPERSEDED - Reference Documents - MCU25 0079

                    Best Practice Erosion And Sediment Control                                  Erosion Hazard Assessment Form


                                                   Erosion Hazard Assessment Form
                                                   Condition                                       Points   Score     Trigger
                                                                                                                       value
                    AVERAGE SLOPE OF DISTURBANCE AREA [1]
                    •   not more than 3%                                [3%  33H:1V]                 0
                    •   more than 3% but not more than 5%               [5% = 20H:1V]                 1
                                                                                                               2         4
                    •   more than 5% but not more than 10%              [10% = 10H:1V]                2
                    •   more than 10% but not more than 15% [15%  6.7H:1V]                           4
                    •   more than 15%                                                                 6
                    SOIL CLASSIFICATION GROUP (AS1726) [2]
                    •   GW, GP, GM, GC                                                                0
                    •   SW, SP, OL, OH                                                                1        3
                    •   SM, SC, MH, CH                                                                2
                    •   ML, CL, or if imported fill is used, or if soils are untested                 3
                    EMERSON (DISPERSION) CLASS NUMBER [3]
                    •   Class 4, 6, 7, or 8                                                           0
                    •   Class 5                                                                       2        4         6
                    •   Class 3, (default value if soils are untested)                                4
                    •   Class 1 or 2                                                                  6
                    DURATION OF SOIL DISTURBANCE [4]
                    •   not more than 1 month                                                         0
                    •   more than 1 month but not more than 4 months                                  2        0         6
                    •   more than 4 months but not more than 6 months                                 4
                    •   more than 6 months                                                            6
                    AREA OF DISTURBANCE [5]
                    •   not more than 1000 m2                                                         0
                    •   more than 1000 m2 but not more than 5000 m2                                   1        0         4
                    •   more than 5000 m2 but not more than 1 ha                                      2
                    •   more than 1 ha but not more than 4 ha                                         4
                    •   more than 4 ha                                                                6
                    WATERWAY DISTURBANCE [6]
                    •   No disturbance to a watercourse, open drain or channel                        0
                                                                                                               0         2
                    •   Involves disturbance to a constructed open drain or channel                   1
                    •   Involves disturbance to a natural watercourse                                 2
                    REHABILITATION METHOD [7]
                    Percentage of area (relative to total disturbance) revegetated by seeding
                    without light mulching (i.e. worst-case revegetation method).
                    •   not more than 1%                                                              0        0
                    •   more than 1% but not more than 5%                                             1
                    •   more than 5% but not more than 10%                                            2
                    •   more than 10%                                                                 4
                    RECEIVING WATERS [8]
                    •   Saline waters only                                                            0        0
                    •   Freshwater body (e.g. creek or freshwater lake or river)                      2
                    SUBSOIL EXPOSURE [9]
                    •   No subsoil exposure except of service trenches                                0        2
                    •   Subsoils are likely to be exposed                                             2
                    EXTERNAL CATCHMENTS [10]
                    •   No external catchment                                                         0
                                                                                                               1
                    •   External catchment diverted around the soil disturbance                       1
                    •   External catchment not diverted around the soil disturbance                   2
                    ROAD CONSTRUCTION [11]
                    •   No road construction                                                          0        0
                    •   Involves road construction works                                              2
                    pH OF SOILS TO BE REVEGETATED [12]
                    •   more than pH 5.5 but less than pH 8                                           0        1
                    •   other pH values, or if soils are untested                                     1

                                                                                        Total Score [13]      13


                    IECA (Australasia)                               November 2008                                     Page 1

Document Set ID: 23959990
Version: 1, Version Date: 23/07/2025