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Canopy Gap of 100m to 195m
(from Australian Capital Territory)
on March 29, 2016.
updated 7 months ago.
<p><b>Background, caveats and Instructions for use of ACTmapi connectivity mapping</b></p> <p>Connectivity conservation seeks to enhance wildlife habitat and the ability of wildlife to move across the landscape between this habitat. It needs to consider both the habitat that an animal is able to live and breed in (habitat for settlement) and that which it can move through (habitat for dispersal). As indicated in the following figure the spatial arrangement of habitat patches across the landscape will also influence whether a particular patch can be utilised as settlement and/or dispersal habitat.</p> <p> </p> <p>The ability for wildlife to move across the landscape is becoming increasingly important to species and ecosystems in light of rapidly changing environmental conditions. Recent CSIRO work suggests that most animals of southern Australian woodlands and forests will not usually cross a canopy gap of more than 100m, and will not travel more than 1.1km away from at least a 10ha sized patch of suitable living habitat.</p> <p> Thus consideration of wildlife connectivity needs to assess habitat condition and spatial arrangement, patch size and the canopy links between habitat patches.</p> <p> </p> <p><b>Habitat value:</b> The ACTMAPI mapping provides habitat value maps for species that typically utilise woodland or forest habitat or are able to utilise both (generalist habitat). Habitat value was derived from:</p> <ul> <li>the best available vegetation and land cover mapping for the ACT region; </li> <li>fine scale (or paddock tree scale) canopy mapping undertaken using SPOT5 satellite imagery; </li> <li>tree stand density predicted using a satellite radar-based measure of above ground biomass; and </li> <li>an effective habitat area analysis that models and measures the habitat value and spatial relationship of a particular habitat patch to other patches of habitat. Large high valuehabitat patches close together scored highly, while isolated low value small patches scored lowly. </li> </ul> <p><b>Regional Links:</b> An analysis was then repeated 550,000 times that took random pairs of points from within any two patches of habitat in the ACT and nearby region and asked “What is the easiest route for a woodland, forest or generalist species to get from one habitat point to the other?” Paths through well connected habitat were repeatedly used to connect differing habitat patch pairs, and these well used paths are identified as regional links, which are the key pathways by which wildlife are likely to move across the ACT Region. </p> <p> </p> <p><b>Use of Habitat value and regional link layers: </b>Habitat value and the regional links layers are the most useful when assessing the potential impact of a development or conservation decision. Key considerations include whether an activity will result in;</p> <p> </p> <ul> <li>loss of areas of high habitat value? If so will the proposal </li> <ul> <li>significantly impact on a habitat patch >100 ha; or </li> <li>reduce a habitat area to less than 10ha; or </li> <li>impact on a habitat patch of 5 -10 ha that could be important to establishing and maintaining a 10 ha habitat patch every 1.1km along a regional or local link. </li> </ul> <li>result in gaps in key regional connectivity locations of >100m between habitat trees; </li> <li>result in canopy gaps of >100m between local links connecting habitat patches identified as having high habitat value. Ideally, any of the above type of losses should be avoided for landscape connectivity value across the ACT to be maintained. In most cases it should be possible to design development so that key thresholds are not broken or in the longer term it may be possible to match losses with restoration activities. </li> </ul> <p><b>Local links and habitat patches:</b> While regional links may be the least cost pathways they may not be able to be actually used by wildlife, if they contain canopy gaps of greater than 100m or if distance along a link between 10 ha habitat patches is greater than 1.1 km. The functionality of a regional link can be checked by overlaying the local links map (which shows all treed areas for which the stepping stone distance does not exceed 100m) and by also overlaying the distribution of habitat patches greater than 10ha.</p> <p> </p> <p><b>Restoration guides - Canopy gap, habitat patches and priority restoration layers:</b> The remaining layers are of particular assistance to the planning of restoration activities. Existing habitat patch sizes of 5 <10 ha are shown as potential areas to effectively create new 10ha patches. These are particularly important where the link distance exceeds 1.1km. Similarly the layer that shows areas where the current canopy gap is from 100m – 195m indicates those places where closing a current gap can be most easily achieved. The Patch Priority Restoration Area layer is derived from the effective habitat area analysis and indicates those areas where the spatial configuration of habitat across the landscape can be most improved through plantings or other regeneration/restoration activities </p> <p> </p> <p><b>Caveats on data:</b></p> <p> </p> <ol> <li>The ACTmapi connectivity mapping is multi-layered and there are many routes by which wildlife can move across the landscape. While allowing site specific consideration of connectivity value and restoration potential, the mapping should not be interpreted as a rigid framework of habitat and links that must all be conserved if wildlife movement is to be maintained across the ACT. </li> <li>The mapping does provide a consistent and transparent means by which connectivity value can be considered within development and planning decisions and a guide to how connectivity across the ACT can be most effectively enhanced. </li> <li>Habitat and linkage values rely on satellite and radar modelling of canopy. Thus, the mapping is based on models that are an approximate representation of the real world. <b>There should be site-based assessment (validation)</b> prior to making site specific development, planning or restoration decisions. </li> <li>The CSIRO movement thresholds on which much of the mapping is based are currently being tested in the field across the ACT. If this testing suggests that changes should be made to any of the parameters. the ACTmapi layers will be updated. There is the capacity within the raw data held by ESDD to produce mapping for an individual species of interest, provided that the threshold parameters for that species are known. </li> <li>The focus of the modelling techniques used in this study is on connectivity in a fragmented landscape and as a result the mapping is suited for use across the ACT lowlands, but not within the continuous upland vegetation of Namadgi National Park and Tidbinbilla Nature Reserve. </li> <li>The ACT connectivity mapping was undertaken by the NSW Office of Environment and Heritage. The study was funded as part of the offset package for the loss of woodland associated with the Kings Highway upgrade. A full study report has been produced, and is entitled Fine Scale Modelling of Fauna Habitat and Connectivity Values in the ACT Region. This study built upon an earlier report entitled the Ecological Connectivity for Climate Change in the ACT and surrounding region, commissioned by the ACT Government as part of Weathering the Change Action Plan 1. The report was undertaken by the Fenner School of Environment and Society, Australian National University. It is recommended that both reports be consulted when use is being made of the connectivity mapping available on ACTmapi. </li> </ol> <p>Both reports can be downloaded from the EPD website at <a href="http://www.environment.act.gov.au/cpr/conservation-research/report_series" target="_blank">http://www.environment.act.gov.au/cpr/conservation-research/report_series</a>.</p> <p> </p> <p><b>Canopy Gap 100 – 195m:</b> A tool which indicates where gaps in the local links canopy layer are from 100m – 195m wide. Theoretically this gap size could be closed by planting one tree in the middle of the gap, and thus this layer is a guide as to how canopy connection could be enhanced most effectively, through targeted clumped planting.</p> <p>Gridcode 1 = canopy gap 100m-195m</p><p><a href="http://creativecommons.org/licenses/by/4.0/"><img src="https://i.creativecommons.org/l/by/4.0/80x15.png" /> </a><a href="https://creativecommons.org/licenses/by/4.0/">Creative Common By Attribution 4.0 (Australian Capital Territory)</a>,</p><p> Please read <a href="http://app.actmapi.act.gov.au/terms.html">Data Terms and Conditions</a> statement before data use.</p>
1 percent AEP Flood
(from Australian Capital Territory)
on December 1, 2015.
updated 7 months ago.
<p>A flood is defined as the covering of normally dry land by water that has escaped or been released from the normal confines of a lake, river, creek or other natural watercourse, a reservoir, canal or dam.</p><p><b>WHAT IS A FLASH FLOOD?</b> - Flash flooding is localised flooding that occurs when heavy rain cannot drain away quicker than it falls. A flash flood is defined by the speed of flooding, not the source or location of flooding. Flash flooding is typically caused by short duration storms over a localised area or catchment. The Bureau of Meteorology describes flash flooding as "Flooding occurring within about six hours of rain, usually the result of intense local rain and characterised by rapid rises in water-levels." <a href="http://www.bom.gov.au/water/awid/initial-f.shtml" target="_blank">reference</a> <br />A local example of a flash flood is the "supercell" thunderstorm that hit Woden in January 1971 where the Canberra Times reported rainfalls up to 100mm in 1 hour were recorded by private rain gauges in the suburbs of Farrer and Torrens." <a href="http://www.bom.gov.au/nsw/sevwx/7079summ.shtml" target="_blank">reference</a></p><p><b>WHAT IS FLOOD RISK?</b> - Flood risk includes both the probability of a flood occurring and the consequences if a flood occurs. The consequences of a flood are in turn affected by the number of people and properties exposed to floodwater and the vulnerability of these people and properties. For example, a river might burst its banks regularly, but if this flooding occurs in an isolated area where there are no people or infrastructure, then the flood risk is considered to be low. Similarly, a river might flood very rarely, but if many people and properties are located near this river and they live in dwellings that are vulnerable to floodwater damage, then the flood risk will be higher.</p><p><b>HOW PRONE IS CANBERRA TO FLOODS?</b> - Canberra planning has always taken into account the need to avoid development in flood prone areas. Since the 1970s planning for new urban development in the ACT has kept development above the 1% Annual Exceedance Probability (AEP) flood level. The local storm water system is designed to cope with the 1% AEP storm flows through a combination of piped flows and overland flows. However, no areas are completely immune to flooding. Floods greater than the 1% AEP are possible, and extremely intense local rainfall can cause localised flash flooding.</p><p><b>WHAT IS A 1% AEP FLOOD?</b> - The 1% AEP flood is a theoretical flood that is estimated to have has a 1% chance of being equalled or exceeded in any year. For example, if you experienced a 1% AEP flood last year, the chance of experiencing a similar magnitude flood this year is still 1%, regardless of when the previous 1% AEP flood was experienced. The 1% probability is calculated using computer modelling, historic rainfall and runoff records and a range of other assumptions. The value of the 1% AEP is an estimate that will change as the climate changes and as more historic rainfall and flooding information is gathered over time that might change assumptions used in the modelling and estimations.</p><p><b>WHAT DOES ACT FLOOD DATA SHOW?</b> - The flood data map shows an estimate of the areas likely to be flooded during a 1% AEP flood - also previously known as the 100 year flood line. The ACT flood map shows flooding extents for riverine flooding only i.e. flooding from named watercourses such as rivers and creeks.</p><p><b>WHEN IS ACT FLOOD DATA BEING RELEASED?</b> - The ACT flood data show the 1% AEP flood for the Molonglo River from Yass Road downstream to the Lake Burley Griffin surrounds and further downstream to below Coppins Crossing. There is a program to update flood studies over the next three years for creeks and some major stormwater channels within and adjacent to urban areas. Once these studies are completed, the 1% AEP flood extents will be made available on the ACT Government's ACTMAPi website.</p><p><b>DISCLAIMER</b></p><p>The ACT Government is providing this flood data for information purposes only. This data is derived from the best available modelling of the catchments and watercourses. The ACT Government cannot and does not guarantee the accuracy and completeness of any data and information contained on this site as, among other reasons, there may have been changes to land use, flow paths or rainfall estimates since the modelling was done. The ACT Government disclaims liability to any person who acts in reliance on the information provided on this site or contained within the reports or plans on it whether that liability is in negligence or on any other legal basis. Persons who would otherwise seek to rely on the data and information contained on this site should make their own inquiries and seek their own expert advice.<br /></p><p>Users of this site should also note that currently data is available only for the Molonglo River, including Lake Burley Griffin. Data for creek systems in Canberra is not displayed because the available data is based on older contour data, past land use and superseded flood models and rainfall estimates. Much of this information is currently being revised and will be displayed on ACTMAPi when it becomes available.</p><p>Refer to the <a href="http://www.actmapi.act.gov.au/dd/flo.html">Flood Map Questions and Answers</a> page, and the <a href="http://www.actmapi.act.gov.au/flood/flood-guide-13-12-2013.pdf">Floods in the ACT information guide (PDF 2.16MB)</a> for more information.</p><p><br /></p><p><a href="http://creativecommons.org/licenses/by/4.0/"><img src="https://i.creativecommons.org/l/by/4.0/80x15.png" /> </a><a href="https://creativecommons.org/licenses/by/4.0/">Creative Common By Attribution 4.0 (Australian Capital Territory)</a>,</p><p> Please read <a href="http://app.actmapi.act.gov.au/terms.html">Data Terms and Conditions</a> statement before use of the data.</p>
ACT Survey Control Marks
(from Australian Capital Territory)
on November 24, 2015.
updated about 1 month ago.
<div> <p>A physical marker that is used as a stable basis for survey measurement. The mark is normally coordinated either horizontally and/or vertically using a recognised coordinate system. The mark can be used to coordinate surveys in the surrounding area. Survey Control Marks are displayed in ACTmapi by Mark type.</p> <p><b> Trig Stations (MC)</b></p> <p> Identifier: district names, old surveyors' names, for example, Tennent, Goodwin.</p> <p> Today's trig stations consist of a ground mark with a white quadripod supporting a black disc above the ground mark. Most of these Trig Stations are part of the ACT Precision Zone, a national geodetic survey and adjustment carried out in the early 1970s. The ACT Precision Zone and its associated marks have been the primary control for all new development in the ACT since the early 1970s. The accuracy of ACT Precision Zone marks is 1 in 250,000.</p> <p><b> Sectional Control Marks (SC)</b></p> <p> Identifier: two alpha plus 1, 2 or 3 numerals, for example, TG116</p> <p> These marks are fixed directly from the ACT Precision Zone at about one kilometre intervals. They usually consist of a deep driven rod protected by yellow concrete posts. Some Sectional Control marks are beaconed (for example, YA90, TG84). The accuracy of Sectional Control marks is 1 in 100,000.</p> <p> <b>Subdivision or Neighbourhood Control Marks or "RMs" (SRM)</b></p> <p> Identifier: three numerals, for example, 363</p> <p> These marks are fixed from the Sectional Control at intervals of between 200 and 400 metres. They usually consist (on placement only) of a galvanised pipe set in concrete protected by two steel droppers painted red and white. There may be an aluminium tag with the mark's identifier either set in the concrete of the mark or wired to one of the steel droppers. The accuracy of Subdivision Control is 1 in 30,000.</p> <p>The subdivisions in Woden Valley (early 1960s) were the first to have Subdivision Control. In suburbs constructed before Gungahlin (pre-1990), Subdivision Control marks were 50 to 100 metres apart. Some of these marks survived development and can be found in open spaces in the suburbs. Only those SRMs in Gungahlin have been entered in the Survey Control Mark Detail Database Control Base. Information on others is contained on plans.</p> <p><b>Coordinated Reference Marks or CRMs (CRM)</b><br /></p> <p> Identifier: CRM plus numerals - starting at 1 eg. CRM7381</p> <p> In today's subdivisions numbered CRM plaques are placed in the kerb and coordinated by survey traverses that start and finish on Sectional or Subdivisional Control marks or other previously coordinated CRMs.</p></div><p> These marks are about 50 to 150 metres apart. Only subdivisions constructed after 1980 contain CRMs that appear on Deposited Plans. Most do not have a height attributed to them.</p><p> Many CRMs have been placed in the older suburbs of Canberra in recent years. These CRMs were coordinated using GPS and are on the AGC system, which is not the system of the surrounding subdivision. Since 16 April 1998 a new style of CRM is used that has a raised nipple for accurate levelling. These are numbered from 10,001 and up.</p><p><b> SR (Steel rod) Marks (SR)</b></p><p> Identifier: SR plus numerals - starting at 1 eg. SR1003</p><p> The ACT Government Survey Office places SR marks in new subdivisions - one for every 100 blocks. The mark consists of a deep driven steel rod contained within a small manhole marked "Survey mark". These SRs are included in the CRM traverses and are precise levelled. Many other SR marks have been placed throughout Canberra. Most are coordinated on the AGC system which may not be the coordinate system of the surrounding subdivision. Not all SR marks are levelled. Conversely, some SRs have been levelled, but are yet to be surveyed for co-ordinates.</p><p><b> Kerb Bench Mark (KBM)</b></p><p> Identifier: KBM plus numerals - starting at 1, for example, KBM5203</p><p> Kerb Bench Marks are placed in the kerbs throughout urban Canberra. They consist of a rectangular brass casting with a nipple and number. Distance between KBMs in new suburbs is 100 to 200 metres and levelling is to 3rd order accuracy. (Many kerbs have moved and differences of more than 3 centimetres have been found). All KBM levels are on the Australian Height Datum (AHD). Precise Bench Marks (PBMs) are listed in the KBM register under their number (for example, PBM13 is KBM13). PBMs are precast concrete blocks that were part of earlier Imperial levelling network on an earlier Canberra datum: Precise Datum or PD. (To convert PD reduced levels (feet) to AHD (metres), subtract 1.07 feet from the PD value, then multiply the result by 0.3048 to give the AHD value).</p><p><b> Rural Bench Marks (RBM)</b></p><p> Identifier: RBM plus numerals - starting at 1, for example, R376</p><p>Rural Bench Marks were placed in the 1970s, at half mile - one kilometre - intervals, along many roads in the ACT. They consist of a star-iron picket driven to its full length into the ground and surrounded by a concrete collar containing a brass plaque with the mark's identifier. One yellow concrete post may be protecting it. In recent years many of these marks have been coordinated from GPS surveys. Other rural bench marks with identifiers "P", "NE", "NW" and "C" can be found on roads in the ACT. Not all have level (AHD) values.</p><p> <b>Photo Control Marks (PC)</b></p><p><b> </b>Identifier: One alpha plus thee numerics.</p><p> Photo Control marks consist of a G.I Pipe in concrete protected by a wood post painted red and white. Many Photo Control marks are for "level only" and their accuracy depends on the scale of the photography they are controlling.</p><p> <b>Alpha Marks (AM)</b></p><p><b> </b>Identifier: Three alphas - starting at AAA</p><p> Alpha Marks usually consist of a GI Pipe in concrete protected by two steel droppers. They are usually placed as a control mark for a specific survey - usually an engineering survey. The accuracy of these marks depends on the nature of the survey they are part of. Many are of an accuracy that does not warrant nominating the coordinate system.</p><p> <b>Miscellaneous Marks (MS)</b></p><p><b> </b>Miscellaneous marks are any mark not contained in the previous categories (apart from Recovery marks). Some examples are old radial blocks, control marks placed before Sectional Control series commenced, dam deformation marks.</p><p> <b>Recovery Marks</b></p><p><b> </b>Identifier: RM plus numeral plus mark it recovers (for example, RM2 Painter) Recovery Marks are close to more important marks.</p><p><a href="http://creativecommons.org/licenses/by/4.0/"><img src="https://i.creativecommons.org/l/by/4.0/80x15.png" /> </a><a href="https://creativecommons.org/licenses/by/4.0/">Creative Common By Attribution 4.0 (Australian Capital Territory)</a>,<br /></p><p> Please read <a href="http://app.actmapi.act.gov.au/terms.html">Data Terms and Conditions</a> statement before data use.</p>
(from Australian Capital Territory)
on July 1, 2016.
updated 7 months ago.
<div>A parcel of land, usually the smallest unit of land that can be held under an individual lease without a requirement for further subdivision. Blocks in ACTMAPi are displayed as Urban and Rural blocks, and have been separated into individual layers based on its lifecycle stage (Registered, Approved, Proposed, Occupied and Retired). URBAN blocks are defined as blocks that appear within a division and have division and section identifiers. RURAL blocks do not usually appear within a division, but may do so if they remain from before the division was created.<br /></div><div><ul><li>REGISTERED: The block appears on a Deposited Plan that has been registered with the Land Titles Office but is not RETIRED or DELETED.<br /></li><li>APPROVED: The block appears on an Approved Plan that has been signed by the Territory Planning Section and the Project Officer for the development, but the block is not REGISTERED, RETIRED or DELETED.<br /></li><li>PROPOSED: The block is proposed but has not reached any other stage.<br /></li><li>OCCUPIED: The block is leased, but does not appear on a registered plan. Leases over unregistered blocks may not be registered at the Land Titles Office, so this stage is used for unregistered blocks with unregistered leases. This normally only occurs in rural areas.<br /></li><li>RETIRED: Retirement of a block occurs when it is replaced by another block.</li></ul><div><p><a href="http://creativecommons.org/licenses/by/4.0/"><img src="https://i.creativecommons.org/l/by/4.0/80x15.png" /> </a><a href="https://creativecommons.org/licenses/by/4.0/">Creative Common By Attribution 4.0 (Australian Capital Territory)</a>,</p><p> Please read <a href="http://app.actmapi.act.gov.au/terms.html">Data Terms and Conditions</a> statement before data use.</p></div></div>