Wab water Management Plan
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Visual Assessment & Rehabilitation Management Plan Proposed Landform Raising – Lot 901 South Western Highway, Whitby 10 October 2012 WA Limestone Page 3 1.0 Background WA Bluemetal has operated at hard rock quarry adjacent to Lot 3 South Western Highway for approximately 20 years. The removal and storage of overburden material is a significant issue faced by all quarry operators. WA Bluemetal is proposing to store overburden material in approximately 10.3 hectares of pasture land within Lot 3. This will involve raising the landform of this area by approximately 3 metres, maintaining the existing profile. The area is then to be rehabilitated back either pasture for grazing or revegetate the area to native vegetation. The original proposal was submitted to the Shire of Serpentine Jarrahdale on 25 November 2011. On 25 June 2012 the Shire determined that a Visual and Rehabilitation Management Plan was required in order to assess the proposal, which forms the basis for the preparation of this document. 2.0 Site Description and Landform The subject site lies near the base of the Darling Scarp, approximately 350 metres east of the South Western Highway Road Reserve. A winter creek runs along the western and southern boundaries of the proposed landform raising site. Elevation of the land ranges from 85m AHD in the south western corner to 126m AHD along the access road to the east of the site. The site is sloping at 1:16 vertical to horizontal on the lower slopes, grading to 1:7 vertical to horizontal over the mid to upper slopes of the site. The Darling Scarp is a visually sensitive area that is recognised in both Local and State Government planning policies. Inappropriate developments located on the Scarp can create visual impacts that might be seen from a large area of viewpoints. South Western Highway is taken as a representative point of potential impact. Closer to the Scarp the impacts can often be screened by local trees, and further away distance factors reduce the perception of impact. The location of the landform raising has been determined on a number of parameters including: • selecting areas where the slopes are less severe • visual management is able to be managed • selecting sparsely vegetated areas • access and servicing issues are minimised An existing winter creek is located along the western and southern portions of the site. A contour drain is to be installed 50m up from the winter creeks to catch any sedimentary runoff, capture water from upslope, and provide for retention and infiltration of that water. A separate Water Management Plan has been prepared in consultation with advice from suitably qualified engineers to address water and drainage considerations. SJS TRIM - IN12/17340 OCM122.9/01/13 Visual Assessment & Rehabilitation Management Plan Proposed Landform Raising – Lot 901 South Western Highway, Whitby 10 October 2012 WA Limestone Page 4 3.0 Geology, Soils and Earthworks The site lies on soils developed on weathered granite associated with the Darling Scarp. On this site the soils are yellow brown stony soils of colluvial origin resting on weathered granite saprolite and saprock. The soils are predominantly formed from soil, clay, stone or granite and dolerite combined with minor gravel being washed down slope to rest on the weathered granite basement. The soils are yellow brown sandy and stony loam soils which become lighter with depth. They are generally friable and well drained. The lower soil horizons are sometimes saprolitic and contain weathered fragments of rock and freed minerals. The location of the soils, on a slope in a higher rainfall area, results in the soils being free from any salinity issues. All soils are well drained because of the slope. Earthworks will be constrained to the previously indicated boundaries of the 10.3 hectare site. No particular construction difficulties are envisaged, due to construction occurring in the summer months which is when the properties of the material are the most ‘construction friendly’. Cut off drains will be installed for stormwater management. Access to the site will be from the existing quarry access road, with a temporary internal road constructed to the lower end of the site in accordance with the construction methodology to build the landform from the creek side heading up the hill. The main risk during earthworks is the risk of soil movement during construction in winter from runoff storm events. Management practices are the same as those on any other sloping lot. The potential for soil removal through water erosion will be mitigated through normal construction practices. The environmental impacts from development will be constrained within the boundaries of the site, which minimises the risk of weed spread, dieback intrusion, waste water disposal, erosion, clearing and visual impact affecting the other areas of the Darling Scarp. SJS TRIM - IN12/17340 OCM122.9/01/13 Visual Assessment & Rehabilitation Management Plan Proposed Landform Raising – Lot 901 South Western Highway, Whitby 10 October 2012 WA Limestone Page 5 3.1 Rehabilitation 3.2 Vegetation Condition The subject site is cleared pasture which has historically been used for low level grazing. No native vegetation will be impacted by the project. The pasture is not considered to be high quality agricultural land. Whilst the soils are good loams they contain a proportion of stone and rock and the site is constrained between two drainage lines and the slope of the scarp. Furthermore there is no local surface or groundwater available in sufficient quantities for irrigated land use. Therefore the only potential agricultural land use is grazing. The slopes and small area make the land unsuitable for cultivated agriculture, and is not suitable for perennial horticulture. It has Low to Very Low agricultural capability. This is confirmed by King PD and MR Wells, 1990, Darling Range Rural land capability Study, Department of Agriculture and Food, Land Resources Series No 3, which shows the land as Balgobin 2 and Darling Scarp 2 both of which have land capability for Grazing, General Horticulture and Perennial Horticulture of IV to V, Low to very low capability. It is noted that the land in such situations on the Darling Scarp is not used for any rural activity apart from low level grazing. Locally there is no cultivation or horticulture. 3.3 Rehabilitation & Revegetation Management The topsoil covering the 10.3 hectare area is proposed to be stripped and stockpiled in stages for future reuse in stages. The stockpiled topsoil will be respread over the overburden material at the earliest opportunity. The landform raising will occur in a series of segments, each not exceeding 2.5 hectares before revegetation and tree planting will take place. The material placement will only take place in the summer months, while the revegetation and planting will predominantly take place in the winter months. This will minimise the area of disturbance at any point in time and any potential visual impact caused by the project. Revegetation will generally consist of the respread of the stockpiled topsoil with the seed bank within the topsoil re-establishing the pasture grasses, which will provide rapid surface stabilisation and reduce any visual impact of the bare soil. In addition tree planting and direct seeding will be conducted along the southern and western boundaries and in clumps within the site to provide additional screening. The use of strategic fire breaks will reduce the need for fuel reduction burning and assists in retaining the remnant trees on site. Fire regulations will however still require driveable perimeter fire breaks. Dieback management practices are recommended even though there are no obvious signs of the disease within the site and the risks to the forest to the east are minimal. SJS TRIM - IN12/17340 OCM122.9/01/13 Yüklə 20,11 Mb. Dostları ilə paylaş:
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