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Executive Summary Eexxeeccuuttiivvee Ssuummmmaarryy

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Executive Summary Eexxeeccuuttiivvee Ssuummmmaarryy Executive Summary EExxeeccuuttiivvee SSuummmmaarryy Introduction This document outlines the rationale and need for the proposed Meander Dam irrigation project. Environmental issues associated with the construction, commissioning and operation of the dam are discussed and details of the commitments made by the proponent with regards to the avoidance, mitigation or management of each issue are provided. The preparation of this document has involved a series of detailed desktop and field based studies to determine the feasibility of the project from an engineering, environmental and economic perspective. Project Rationale The main purpose of the Meander Dam proposal is to provide a reliable irrigation supply to agricultural users in the region. In September 2001, preliminary desktop studies were undertaken to identify and address issues with the potential to impact on the feasibility of the project. Alternative options for the design and location of the dam were assessed, as were alternatives for the avoidance or mitigation of environmental impacts of the proposed structure. Pressure on water resources in the Meander Catchment currently limits further agricultural development and productivity in the area. Competition for this limited resource results in a virtual cessation of flow in the lower Meander River during the irrigation period and resultant water quality issues have a significant impact on the aquatic environment and on town water supplies. A water management plan is currently under development and is expected to address environmental flow concerns through the implementation of more DPEMP - Meander Dam Proposal DRAFT Executive Summary i sustainable water management practices. However, increasing the environmental water allocation is likely to further limit agricultural production. The dam project proposed in this document aims to increase the availability and reliability of water for irrigated agricultural use whilst protecting the environmental flow allocations required to maintain or improve ecological health in the Meander River. Studies Completed During the Preparation of this Document Four studies were commissioned to enable objective assessment of the feasibility of the proposed dam. This Development Proposal and Environmental Management Plan (DPEMP) has been prepared using information derived from these fours studies, the purpose and content of which is provided in the following sections. Desktop feasibility review This review involved an extensive investigation of existing literature including previous technical reports, scientific papers and existing management plans and strategies. It also included searches of all relevant government databases and the assessment of existing data relevant to the project. The purpose of this review was to: ! identify technical knowledge gaps and recommend further investigations required to address them. Issues identified during this review have been investigated further in the following three studies. ! identify changes to the existing environment since the previous studies. ! identify potential ‘fatal flaw’ issues affecting the feasibility of the dam. The identification of irreconcilable issues would have resulted in termination of the project. Engineering feasibility studies Engineering issues identified during the desktop review and subsequently investigated include: ii Executive Summary DRAFT DPEMP - Meander Dam Proposal ! a geological investigation into potential sources of clay and rock for alternative dam designs through desktop and field investigations; ! an investigation into the potential for landsliding within the reservoir area; ! a review of the latest hydrological information on catchment yield and flood hydrology using the latest analytical techniques; ! a review of the preferred type of dam construction designed to the current ANCOLD guidelines and incorporating the latest technology to minimise environmental impact; ! a review of the viability of a mini-hydro power-station associated with the dam given the changed renewable energy market legislation, and identification of possible transmission lines routes if required; and ! potential seepage through Huntsman saddle - this was investigated through a thorough review of the existing information. Environmental feasibility studies Environmental issues identified during the desktop review and subsequently investigated include: ! potential water quality issues. These were investigated through the implementation of a short-term monitoring program aimed at assessing water quality under typical spring flow conditions. ! lack of knowledge regarding aquatic species at the site and their environmental requirements was addressed through a program of fish and invertebrate monitoring and assessment. ! the environmental flow requirements of the Meander River downstream of the dam were not well understood. These were assessed using habitat based IFIM techniques involving extensive field surveys. ! the significance and value of the floral and faunal communities at the site required further assessment, particularly with regards to threatened species identified during the desktop review. Flora and fauna surveys were performed at the site according to DPIWE protocols. ! potential Aboriginal heritage values were identified during the desktop review and were further investigated through field surveys. DPEMP - Meander Dam Proposal DRAFT Executive Summary iii Economic feasibility studies The economic feasibility studies identified a number of issues that required further investigation, including: ! the supply of water to the farm-gate required assessment to identify the water demand, and the capital and pumping costs required to get water to the irrigation areas and potential water losses. This was addressed through landholder surveys; and ! identification of the potential (expanded) irrigation area by assessment of land suitability and landholder acceptance of the project. Dam Location The site for the proposed Meander Dam lies in the upper reaches of the Meander River Catchment, in Tasmania’s central North. The site is approximately 50 km southwest of Launceston. Figure 1 Location of proposed Meander Dam iv Executive Summary DRAFT DPEMP - Meander Dam Proposal The proposed dam site is to be located at 468342E 5384048N, in a narrow, steep- sided valley between Warners Sugarloaf and Archers Sugarloaf, at approximately 400 m asl, at the foot of the Great Western Tiers Conservation Area. The Catchment The proposed dam will receive waters from the Meander River and a number of tributary creeks and rivulets flowing down from the sides of the Central Plateau. The dam has a catchment area of just under 16000 ha. In addition to the upper Meander River, the catchment waterways include Warners Creek, Sales Rivulet, Huntsman Rivulet and Dunning Rivulet. Land use and tenure The nearest centre is the town of Meander, some 4.5 km north of the proposed dam. The area is mainly used for agriculture, primarily cattle grazing, and forestry operations. Forestry operations during the 1980s saw a large percentage of the proposed inundation area clearfelled and subsequently regenerated. Parcels of land to the south of the inundation area are laid out in intensive eucalypt plantations. The dam is unlikely to affect forestry operations in their current form. Much of the area is State Forest and Public Reserve (approximately 245 ha), with 87 ha of privately owned land to the west of the inundation area. The private land is laid out in pasture for grazing. Six residences are within half a kilometre of the proposed inundation, and of these only two are within 150 m of the likely new shoreline. Responsibility for the land within the inundation area rests with four bodies. State Forest is managed by Forestry Tasmania, Public Reserve is under Department of Primary Industries, Water and Environment, and the private land is owned by the Rivers and Water Supply Commission and Meander Valley Council. Site and public access There are two tracks that may be upgraded to form suitable access to the proposed dam site. DPEMP - Meander Dam Proposal DRAFT Executive Summary v Figure 2: Tracks within the inundation zone. One track leads in from Warners Road, which enters the study area from the Jackeys Marsh vicinity. This track was originally well formed and gravelled but much of the track is now substantially overgrown and in need of maintenance. The track is likely to date from the clearfelling undertaken on the site during the 1980s. Close to the proposed site of the dam wall, the benching has suffered some erosion but is largely intact. The second track extends from an access spur from Huntsman Road, entering the study area from the Meander township area. This track is in almost identical condition to the track entering from Warners Road, but also has two small bridges across creeks, both of which are currently in a very dilapidated condition. vi Executive Summary DRAFT DPEMP - Meander Dam Proposal The filling of the dam will have an effect on two major access roads- Huntsman Road and Bessels Road. Huntsman Road is the sole access road to a number of private dwellings and is also sole access for tourists wishing to visit the popular Meander Falls area. Bessels Road is less travelled, being used for access to the forestry operations in the hills to the south of the inundation area and as access to the Meander River itself for recreational purposes. Provisions will be made to maintain vehicle access for these roads through realignment to above the inundation zone of the
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