19553 - Erosion and Sediment Control Plan

 Introduction
Tod Consulting was engaged by Tea Tree Properties Pty Ltd (Mark Bain Constructions) to prepared
civil engineering design drawings for the planned subdivision at Lake Macdonald Drive, Cooroy
approved by Development Approval reference RAL19/0018. As the works involve bulk earthworks
for the construction of new roads and building pads an Erosion and Sediment Control Plan is
required. This report outlines the risk profile for the individual catchments and work areas of the site
and the proposed control measure to be adopted during the bulk earthworks operations.

This report shall be read in conjunction with the erosion and sediment control plans in the civil
engineering design drawing set reference 19553 – C1101




1. Risk Assessment
The site can be divided into five distinct work areas/catchments, as follows:

    1.   Road 1 from Chainage 0.0 to Chainage 246 (crest)
    2.   Road 1 from Chainage 246 to Chainage 448 (cul-de-sac)
    3.   Road 2 (Wilgee Court) from Chainage 0.0 to Chainahe 80 (end)
    4.   Lot filling to lot 10 (spoil disposal area)
    5.   Individual lot building pads and driveways


Note that with the exception of site area 2 & 4 each area discharges to a different/individual location
within the site, so it is not considered necessary to stage the earthworks activies. Notwithstanding
it is likely that some staggering of disturbed areas will naturally occur.

Based on the above area each work area has been assess independently to determine the erosion
risk using the formula outlined in Appendix F of IECA guidelines (T.A.S.K number – equation F1).

Where:

H = Numerical Value of the TASK number
T = Duration of Soil disturbance (months)
A = Total area of soil disturbance (m2)
S = Slope Factor (Tbale F2)
K = Soil erosivity factor (RUSLE K-factor)

As outlined in section F2 if the calculation of the T.A.S.K number is less than 200 then the risk is
considered low.

With the exception of work area 1 the erosion risk of the remaining areas is consdiered to be low
based on the following T.A.S.K number calculations outlined below.

Area 1

Area 1 consists of two catchments that drain to a common sag point at Ch 117

Area 1A
T = 1 month
A = 2340m2
S = 0.69 (Ave slope 4.7%, length 117m)
K = 0.047 (inorganic clays of high plasticity)
H = 76



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