MCU25 0079 - Negotiated Reference Documents (As Published)

                    Best Practice Erosion And Sediment Control                                 Erosion Hazard Assessment Form


                             The left-hand-side of the table provides an indication of the type of sediment
                             basin that will be required (Type C, F or D). The right-hand-side of the table
                             provides an indication of the likely erodibility of the soil based on the Revised
                             Universal Soil Loss Equation (RUSLE) K-factor.

                             Table 3 provides some general comments on the erosion potential of the various
                             soil groups.

                                                 Table 1 – Score if soil K-factor is known
                                                                      RUSLE soil erodibility K-factor
                                                  K < 0.02            0.02<K<0.04          0.04<K<0.06              K > 0.06
                           Score                       0                   1                      2                     3

                                             Table 2 – Statistical analysis of NSW soil data [1]

                     Unified             Likely sediment basin                  Probable soil erodibility K-factor (%) [2]
                       Soil                classification (%)
                      Class            Dry                 Wet            Low         Moderate           High          Very High
                     System
                                   Type C       Type F       Type D     K < 0.02     0.02<K<0.04      0.04<K<0.06       K > 0.06
                       GM               30        58             12        12             51              26                 12
                       GC               42        33             25        13             71              17                 0
                       SW               40        48             12        49             39              12                 0
                        SP              53        32             15        76             18               5                 1
                       SM               21        67             12        26             48              25                 1
                        SC              26        50             24        16             64              18                 2
                       ML               5         63             32        4              35              45                 16
                        CL              9         51             39        12             56              19                 13
                        OL              2         80             18        34             61               5                 1
                       MH               12        41             48        15             19              41                 25
                       CH               5         44             51        39             43              11                 7
                    Notes: [1]         Analysis of soil data presented in Landcom (2004).
                           [2]         Soil erodibility based on Revised Universal Soil Loss Equation (RUSLE) K-factor.

                    Unified Soil Classification System (USCS)
                    GW       Well graded gravels, gravel-sand mixtures, little or no fines
                    GP       Poorly graded gravels, gravel-sand mixture, little or no fines
                    GM       Silty gravels, poorly graded gravel-sand-silt mixtures
                    GC       Clayey gravels, poorly graded gravel-sand-clay mixtures
                    SW       Well graded sands, gravelly sands, little or no fines
                    SP       Poorly graded sands, gravelly sands, little or no fines
                    SM       Silty sands, poorly graded sand-silt mixtures
                    SC       Clayey sands, poorly graded sand-clay mixtures
                    ML       Inorganic silts & very fine sands, rock flour, silty or clayey fine sands with slight plasticity
                    CL       Inorganic clays, low–medium plasticity, gravelly clays, sandy clays, silty clays, lean clays
                    OL       Organic silts and organic silt-clays of low plasticity
                    MH       Inorganic silts, micaceous or diatomaceous fine sandy or silty soils, elastic silts
                    CH       Inorganic clays of high plasticity, fat clays
                    OH       Organic clays of medium to high plasticity




                    IECA (Australasia)                                  November 2008                                        Page 3

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