The Flood Map for Planning (Rivers and Sea) includes several layers of information. This dataset covers Flood Storage Areas. It shows those areas that act as a balancing reservoir, storage basin or balancing pond. Their purpose is to attenuate an incoming flood peak to a flow level that can be accepted by the downstream channel. It may also delay the timing of a flood peak so that its volume is discharged over a longer time interval. We have assumed that flood storage areas act perfectly and give the same level of protection as when our assessment of the area was carried out. Flood storage areas do not completely remove the chance of flooding and can be overtopped or fail in extreme weather conditions.

This dataset is designed to raise awareness of the likelihood of flooding and to encourage people living and working in areas prone to flooding to find out more and take appropriate action.

Flood Storage Areas show those areas that act as a balancing reservoir, storage basin or balancing pond. Their purpose is to attenuate an incoming flood peak to a flow level that can be accepted by the downstream channel. It may also delay the timing of a flood peak so that its volume is discharged over a longer time interval. Flood Storage Areas that are not yet shown will be gradually added as information becomes available.

The Flood Map for Planning (Rivers and Sea) includes several layers of information. This dataset covers Flood Zone 2 and should not be used without Flood Zone 3. It is our best estimate of the areas of land at risk of flooding, when the presence of flood defences are ignored and covers land between Zone 3 and the extent of the flooding from rivers or the sea with a 1 in 1000 (0.1%) chance of flooding each year. This dataset also includes those areas defined in Flood Zone 3. This dataset is designed to support flood risk assessments in line with Planning Practice Guidance ; and raise awareness of the likelihood of flooding to encourage people living and working in areas prone to flooding to find out more and take appropriate action. The information provided is largely based on modelled data and is therefore indicative rather than specific. Locations may also be at risk from other sources of flooding, such as high groundwater levels, overland run off from heavy rain, or failure of infrastructure such as sewers and storm drains. The information indicates the flood risk to areas of land and is not sufficiently detailed to show whether an individual property is at risk of flooding, therefore properties may not always face the same chance of flooding as the areas that surround them. This is because we do not hold details about properties and their floor levels. Information on flood depth, speed or volume of flow is not included. NOTE: We have paused quarterly updates of this dataset. Please visit the “Pause to Updates of Flood Risk Maps” announcement on our support pages for further information. We will provide notifications on the Flood Map for Planning website to indicate where we have new flood risk information. Other data related to the Flood Map for Planning will continue to be updated, including data relating to flood history, flood defences, and water storage areas. Attribution statement: © Environment Agency copyright and/or database right 2023. All rights reserved. Some features of this map are based on digital spatial data from the Centre for Ecology & Hydrology, © NERC (CEH). © Crown Copyright and Database Rights 2023 OS AC0000807064.

Thames Estuary flood storage areas are potential areas of riverside with the primary purpose to receive and store tidal flood flows during large storm surge events. They aim to help reduce extreme flood levels and prevent flooding further upstream. There are four potential flood storage areas which were first identified in the TE2100 Plan (2012).

This file contains the land conservation focus areas that provide the greatest benefits to coastal water resources. Focus areas are targeted specifically to address threats associated with existing and future development, including: 1. Pollutant attenuation and removal: riparian buffers that intercept stormwater runoff and at the same time maintain natural cover adjacent to surface waters, and riparian wetlands that are highly efficient at treating pollutants already in surface waters; 2. Flood storage and risk mitigation: areas across the watershed with high flood storage capacities that reduce flood risks to downstream infrastructure, and natural areas that will accommodate sea level rise and salt marsh migration; 3. Public water supply: lands that safeguard surface and groundwater resources for human consumption. A feature class is included for each of the three target focus areas listed above. Additionally, a fourth feature class is included that combines the three focus areas, differentiating between areas of single and multiple target benefits.

Te Rahu Flood Storage Basin as identified in the Whakatāne District Plan maps.

We generate a global reservoir flood storage capacity data.

GHD Pty Ltd was engaged by Liverpool City Council to prepare a Floodplain Management Study for the Liverpool Central Business District (CBD) in accordance with the NSW Floodplain Management Manual. The Liverpool Central Business District (CBD) is at risk of extensive overland flooding, potentially affecting commerce and public safety. During larger events, stormwater runoff from within the CBD catchment exceeds the capacity of the existing local stormwater network. This eventuates in flooding of buildings and business premises, which in turn could lead to expensive clean-up costs, loss of stock, and loss of revenue. Flood behaviour and flood categorisation was undertaken based on DRAINS model simulations, and a number of floodways and flood storage areas have been categorised throughout the Liverpool CBD. The most severely affected areas include Macquarie, George and Moore Streets. Overland flow in these areas has been simulated at depths in excess of 0.5 m in places and these have been designated as High Hazard areas. A key objective was to consult with the community and relevant stakeholders to determine the community's attitude to past flooding, to document anecdotal history about flooding, and to assist in developing recommendations that are suitable and acceptable for the community. Businesses were surveyed and a public meeting was held in the Liverpool City Council Chambers on the 28th June 2005. Of the sample of 30 surveyed businesses, all of which were identified in flood affected areas, only six 6 indicated that they had experienced flood impacts. The majority had little awareness of the potential flood impacts to their property. Whilst the low level of flood awareness may be indicative of a turnover of business management, ownership or tenancy, overall this indicates that the CBD business community may not be suitably prepared for flood impacts. The degree of social impact is likely to be greater in a community that is not aware or prepared for the flood event. A number of flood management options have been investigated, namely property modification, response modification and flood modification. In addition a number of structural drainage solutions have been considered in this and other reports. Works, which divert flow from the South-East catchment away from the main system in Northumberland Street and diverting flow from the Central-North catchment. A new outlet is provided to the Georges River at Moore Street. Appropriate flood management options and issues were evaluated using a benefit/cost analysis. The results showed that the two structural drainage solutions (Section A works and both Section A and B works) have highest benefit/cost ratio. These are followed by a public flood awareness scheme. Flood planning levels (FPLs) are an important tool in the management of flood risk .It is recommended that FPLs and controls be adopted for the Liverpool CBD in particular to manage re-development. These should recognise that flooding in the Liverpool CBD is on account of local overland flow and key planning parameters would need to account for the predominantly commercial land use in the CBD. The total cost of implementing the structural works associated with this study is approximately $7.39M (Section A works only) and $9.89M (Section A and B works) A variety of potential funding sources include the Department of Infrastructure, Planning and Natural Resources through the subsidised Flood Mitigation Program, Council funds, Section 94 contributions from future development, contributions from residents or businesses.

As part of a study to quantify floodplain flood attenuation ecosystem services, datasets were developed representing a baseline (current floodplain condition) and counterfactual (floodplain flood storage removed) scenario for 18 sites in the Schuylkill River Watershed, Pennsylvania. This data release contains rasters (3-m resolution) of baseline and counterfactual flood depth grids for the 0.5, 0.2, 0.1, 0.04, 0.02, and 0.01 annual exceedance probability (AEP) scenarios in the Schuylkill River Watershed, Pennsylvania. Depth grid raster datasets were used as input for riverine flood modeling in the Federal Emergency Management Agency HAZUS Program to estimate damages to buildings under various flood intensities. The HAZUS Program is a tool to estimate damages and associated losses due to natural disasters like floods. The data release also contains polyline shapefiles of (1) six floodplain storage volume cross-sections for the 0.01 AEP baseline scenario flood inundation boundary at each USGS streamgage of interest and (2) water surface cross-sections extending across all areas of interest inundation boundaries based on the 0.01 counterfactual scenario boundary. Floodplain storage volume cross-sectional lines (Schuylkill_Volume_xns) were used in the approximation of average floodplain flood water storage capacity of each area of interest. Water surface cross-sections (Schuylkill_DepthGrid_xns) were used for water surface interpolation in depth grid processing.

The Department of Water and Environmental Regulation produces floodplain mapping of rivers and major watercourses and provides floodplain development advice to ensure that proposed floodplain development has adequate flood protection and does not impact on the existing flood regime of the area. This advice is related to major river flooding only. Other issues, such as stormwater drainage and envirionmental and ecological considerations are not addressed. This dataset contains 10 polygons …Show full descriptionThe Department of Water and Environmental Regulation produces floodplain mapping of rivers and major watercourses and provides floodplain development advice to ensure that proposed floodplain development has adequate flood protection and does not impact on the existing flood regime of the area. This advice is related to major river flooding only. Other issues, such as stormwater drainage and envirionmental and ecological considerations are not addressed. This dataset contains 10 polygons illustrating the area of land adjacent to a water body which is subject to flooding during a range of possible design events: 1 in 10 (10%) AEP floodplain 1 in 20 (5%) AEP floodplain 1 in 25 (4%) AEP floodplain 1 in 50 (2%) AEP floodplain 1 in 100 (1%) AEP floodplain Designated flood event floodplain 1 in 200 (0.5%) AEP floodplain 1 in 500 (0.2%) AEP floodplain Maximum channel capacity Probable maximum flood Note: To see the full scope of the floodplain mapping, 12 dataset layers are required to be loaded in the following order: FLOODPLAIN DATASET LAYERS: FPM Flood Level Points (m AHD) FPM Flood Level Contours (m AHD) FPM 1 in 100 (1%) AEP Floodway and Flood Fringe Line FPM Extent of Flooding FPM Levee Banks FPM Location of Cross Sections FPM 1 in 100 (1%) AEP Floodplain Development Control Area FPM Map Index FPM Bridges FPM Special Development Condition Area FPM 1 in 100 (1%) AEP Floodway and Flood Fringe Area FPM Floodplain Area The dataset covers the following areas: Avon River - Toodyay to Beverley. Blackwood River – Augusta, Bridgetown, Nannup and Boyup Brook Townsites. Bow River - Bow Bridge Townsite. Capel River - Capel Townsite. Chapman River – Geraldton Townsite. Coblinine River & Dorderyemunning Creek - Wagin Townsite. Collie River - Collie Townsite. Denmark River - Denmark Townsite. Fitzroy River - Fitzroy Crossing Townsite. Five Mile Brook - Bunbury Townsite. Gascoyne River - Carnarvon Townsite and the Lower Gascoyne (contains both pre and post-stage 2 Carnarvon flood mitigation works mapping: refer to "COMMENTS" field). Greenough River – Indian Ocean to Walkaway. Gribble Creek - Kalgoorlie Townsite. Harding River - Roebourne Townsite. Irwin River - Dongara Townsite. Margaret River – Margaret River Townsite. Nullagine River – Nullagine Townsite. Preston River - Boyanup and Donnybrook Townsites. Serpentine River, Murray River and the Peel Inlet / Harvey Estuary - Peel Inlet / Harvey Estuary to Pinjarra and south to the Darling Scarp (Murray River) and Peel Inlet / Harvey Estuary to Wellard and east to South Western Highway (Serpentine River). Swan River, Canning River and Tributaries: Fremantle to Walyunga National Park (Swan River) and Canning Bridge to Brookton Highway (Canning River). Tributaries include Bennett Brook, Blackadder Creek, Ellen Brook, Helena River, Jane Brook, St Leonards Creek, Susannah Brook (Swan River) and Southern River/ Wungong Brook (Canning River). Toby Inlet – Quindalup Townsite. Turkey creek - Warmun Aboriginal Community. Vasse-Wonnerup Estuaries, Broadwater and New River - Busselton Townsite. Wagin Townsite. Willyung Creek – Albany Townsite. Yakamia Creek – Albany Townsite. The dataset also covers the following areas: However these are not design flood events, they are major historical or alternative scenario flood events that have been used (instead of the design flow, if present) to set planning & development guidelines as part of the floodplain management strategy. Refer to "FPM Historical Extent of Flooding" metadata for more details. Cohn Creek - Merredin Townsite. Corrigin Townsite. Gordon River - Tambellup Townsite. Turkey Creek - Warmun Aboriginal Community (contains both design and historical information). Yakamia Creek – Albany Townsite (contains both design and alternative scenario information). Glossary: Annual exceedance probability (AEP) - the likelihood of occurance of a flood of a given size or larger in any one year; usually expressed as a percentage. 1 in 100 AEP flood - this means that there is a 1 in 100 (or 1%) chance of a flow of this size or larger occurring in any one year. This flood has a 50% chance of being experienced at least once in a person's life time. The 1 in 100 AEP flood has been generally adopted in Australia and overseas as the basis for floodplain management planning. Flood fringe - the area of the floodplain, outside of the floodway where development could be permitted provided it is compatible with flood hazard and building conditions provide an adequate level of flood protection. These areas are generally covered by still or very slowly moving waters during a 1 in 100 (1%) AEP flood. Floodplain - the portion of a river valley next to the river channel which is covered with water when the rier overflows its banks during major river flows. The term also applies to land adjacent to estauries which is subject to flooding. Floodway - the river channel and a portion of the floodplain where a significant flow or storage of water occurs during floods. If the floodway is even partially blocked then the natural flooding regime of th area may be detrimentally impacted with flood levels being raised and affecting areas which may not have been previously affected. Development in floodways is to be avoided wherever possible. Australian Height Datum (AHD) - is a geodetic datum for altitude measurement in Australia. It was adopted in 1971 by the National Mapping Council as the datum to which all vertical control for mapping is to be referred. The datum is based on the mean sea level (1966-1968) being assigned the value 0.000m on the Australian Height Datum (AHD) at 30 tide gauges around the coast of the Australian continent. This dataset was formally known as FPM Floodplain Area (DOW-054)

The impoundment areas of the flood retention basins (HWRB) on waters 2 are shown. Order at one HQ100 (100 annual flood event). The storage areas correspond to the so-called reservoir area of the technical facility of the HWRB. It is part of the HWRB. The reservoirs form a floodplain on waters 2. Order according to §100 (2) SächsWG. The restrictions in flood areas according to §78 WHG apply here.

The U.S. Geological Survey (USGS), in cooperation with the city of Harrisonville, Missouri, assessed flooding of Muddy Creek resulting from varying precipitation magnitudes and durations, antecedent soil moisture conditions, and channel conditions. The precipitation scenarios were used to develop a library of flood-inundation maps that included a 3.8-mile reach of Muddy Creek and tributaries within and adjacent to the city. Hydrologic and hydraulic models of the upper Muddy Creek Basin were used to assess streamflow magnitudes associated with simulated precipitation amounts and the resulting flood-inundation conditions. The U.S. Army Corps of Engineers Hydrologic Engineering Center-Hydrologic Modeling System (HEC–HMS; version 4.4.1) was used to simulate the amount of streamflow produced from a range of rainfall events. The Hydrologic Engineering Center-River Analysis System (HEC–RAS; version 5.0.7) was then used to route streamflows and map resulting areas of flood inundation. The hydrologic and hydraulic models were calibrated to the September 28, 2019; May 27, 2021; and June 25, 2021, runoff events representing a range of antecedent moisture conditions and hydrologic responses. The calibrated HEC–HMS model was used to simulate streamflows from design rainfall events of 30-minute to 24-hour durations and ranging from a 100- to 0.1-percent annual exceedance probability. Flood-inundation maps were produced for USGS streamflow stages of 1.0 feet (ft), or near bankfull, to 4.0 ft, or a stage exceeding the 0.1-percent annual exceedance probability interval precipitation, using the HEC–RAS model. The consequence of each precipitation duration-frequency value was represented by a 0.5-ft increment inundation map based on the generated peak streamflow from that rainfall event and the corresponding stage at the Muddy Creek stage reference _location. Seven scenarios were developed with the HEC–HMS hydrologic model with resulting streamflows routed in a HEC-RAS hydraulic model and these scenarios varied by antecedent soil-moisture and channel conditions. The same precipitation scenarios were used in each of the seven antecedent moisture and channel conditions and the simulation results were assigned to a flood-inundation map condition based on the generated peak flow and corresponding stage at the Muddy Creek reference _location. This data release includes: 1) tables summarizing the model results including the flood-inundation map condition of each model scenario for dry (CNI; Muddy_Creek_summary_table_1_1.csv), normal (CNII; Muddy_Creek_summary_table_1_2.csv), and wet (CNIII; Muddy_Creek_summary_table_1_3.csv) antecedent soil moisture conditions (MuddyCreek_summary_tables.zip); 2) a shapefile dataset of the streamflow inundation extents at Muddy Creek reference _location stages of 1.0 to 4.0 feet (MuddyCreek_inundation_extents.zip containing MudHarMO.shp); 3) a raster dataset of the streamflow depths at Muddy Creek reference _location stages of 1.0 to 4.0 feet (MuddyCreek_inundation_depths.zip containing MudharMO_X.tif where X = 1,2,3,4,5,6,7 corresponding to inundation map stages of 1.0, 1.5 , 2.0, 2.5, 3.0, 3.5, 4.0 feet)); 4) tables of hydrologic and hydraulic model performance and calibration metrics, locations of continuous pressure transducers (PTs; MuddyCreek_PT_locations.zip) and high-water marks (HWMs; MuddCreek_HWM_locations.zip) used in assessment of model calibration and validation, and time series of pressure transducer data (MuddyCreek_PT_time_series.zip) found in MuddyCreek_model_performance_calibration_metrics.zip; 5) hydrologic and hydraulic model run files used in the simulation of dry hydrologic response conditions (CN_I conditions) and effects of proposed detention storage (MuddyCreek_dry_detention.zip); 6) hydrologic and hydraulic model run files used in the simulation and calibration of dry hydrologic response conditions (CN_I conditions) and current (2019) existing channel conditions (MuddyCreek_dry_existing_conditions.zip); 7) hydrologic and hydraulic model run files used in the simulation of normal hydrologic response conditions (CN_II conditions) and effects of cleaned culverts (MuddyCreek_normal_clean_culverts.zip); 8) hydrologic and hydraulic model run files used in the simulation of normal hydrologic response conditions (CN_II conditions) and effects of detention storage (MuddyCreek_normal_detention.zip); 9) hydrologic and hydraulic model run files used in the simulation and calibration of normal hydrologic response conditions (CN_II conditions) and current (2019) existing channel conditions (MuddyCreek_normal_existing_conditions.zip); 10) hydrologic and hydraulic model run files used in the simulation of wet hydrologic response conditions (CN_III conditions) and effects of proposed detention storage (MuddyCreek_wet_detention.zip); 11) hydrologic and hydraulic model run files used in the simulation and calibration of wet hydrologic response conditions (CN_III) and current (2019) existing channel conditions (MuddyCreek_wet_existing_conditions.zip). 12) Service definition files of the Muddy Creek water depths of inundated areas (MuddyCreek_Inundation_depths.sd) and Muddy Creek inundation area polygons (MuddyCreek_inundation_extents.sd) added on September 7, 2022.

The purpose of the Flood Plain Overlay District (FPOD) is to preserve and protect streams, brooks, ponds, lakes, and other water courses and their adjoining lands within the Town; to protect the health and safety of persons and property against the hazards of flooding; to preserve the natural flood control characteristics, and the flood storage capacity of the flood plain, and to preserve and maintain the ground water table and water recharge areas within the flood plain; to protect the community against the detrimental use and the development of lands adjoining such water courses and to conserve the watershed areas of the Town for the health, safety, and welfare of the public.

This dataset provides compiled and computed data from 1900 through 2017 associated with Streamflow statistics used to perform regional analyses for the Brazos, Colorado, Big Cypress, Guadalupe, Neches, Sulphur, and Trinity river basins. These seven river basins are mostly within Texas, but parts of some of the basins extend into New Mexico and Louisiana. Because changes in precipitation, temperature and groundwater levels can appreciably affect streamflow, understanding changes in streamflow requires taking these forcing variables into account. Long-term streamflow statistics for these seven river basins were derived by analyzing streamflow data and other observed climatological variables. Data include tables of accumulated surface-water storage data modified from the National Inventory of Dams (NID), (Table 1), delineation of State counties or parishes by study basin (Table 2), National Oceanic and Atmospheric Administration (NOAA) precipitation stations by study basin (Table 3), and daily mean precipitation data (Table 4). In addition to data collected in 188 counties in Texas, this data release includes data collected in 4 counties in New Mexico, and 1 parish in Louisiana. Data not included in this dataset include temperature and groundwater-level elevation data, which are referenced in the associated larger work citation.

The Department of Water and Environmental Regulation produces floodplain mapping of rivers and major watercourses and provides floodplain development advice to ensure that proposed floodplain …Show full descriptionThe Department of Water and Environmental Regulation produces floodplain mapping of rivers and major watercourses and provides floodplain development advice to ensure that proposed floodplain development has adequate flood protection and does not impact on the existing flood regime of the area. This advice is related to major river flooding only. Other issues, such as stormwater drainage and envirionmental and ecological considerations are not addressed. Both the floodway and flood fringe make up the 1 in 100 (1%) annual exceedence probability (AEP) floodplain, however there are areas where the floodplain exists but the floodway and flood fringe does not. In such situations, a different floodplain management strategy applies (for example, the Swan River between the Narrows and Canning Bridges). This dataset comprises two polygons - Flood fringe, and Floodway. The flood fringe is that part of the floodplain where development may be considered acceptable subject to certain building conditions that will provide adequate flood protection. The floodway is that part of the 1 in 100 (1%) AEP floodplain where development that is considered obstructive to major flows is not acceptable as it would increase flood levels upstream. No new buildings are acceptable in the floodway. Note: To see the full scope of the floodplain mapping, 12 dataset layers are required to be loaded in the following order: FLOODPLAIN DATASET LAYERS: FPM Flood Level Points (m AHD) FPM Flood Level Contours (m AHD) FPM 1 in 100 (1%) AEP Floodway and Flood Fringe Line FPM Extent of Flooding FPM Levee Banks FPM Location of Cross Sections FPM 1 in 100 (1%) AEP Floodplain Development Control Area FPM Map Index FPM Bridges FPM Special Development Condition Area FPM 1 in 100 (1%) AEP Floodway and Flood Fringe Area FPM Floodplain Area The dataset covers the following areas: Avon River – Toodyay, Northam, York and Beverley Townsites. Blackwood River – Augusta, Bridgetown, Nannup and Boyup Brook Townsites. Brunswick River - Greater Bunbury Coblinine River & Dorderyemunning Creek - Wagin Townsite. Collie River - Collie Townsite. Chapman River – Geraldton Townsite. Denmark River – Denmark Townsite. Gascoyne River - Carnarvon Townsite and the Lower Gascoyne. Gribble Creek - Kalgoorlie Townsite. Harding River - Roebourne Townsite. Irwin River - Dongara Townsite. Lower Collie River - Greater Bunbury. Preston River - Donnybrook Townsite. Serpentine River, Peel, Birrega & Oaklands Drains, Murray River and the Peel Inlet / Harvey Estuary - Peel Inlet / Harvey Estuary to Pinjarra and south to the Darling Scarp (Murray River) and Peel Inlet / Harvey Estuary to Wellard (Peel Main Drain), east to South Western Highway (Serpentine River) and north to Wungong Brook (Birrega Drain). Swan River, Canning River and Tributaries: Perth - Fremantle to Walyunga National Park (Swan River) and Canning Bridge to Brookton Highway (Canning River). Tributaries include Bennett Brook, Blackadder Creek, Ellen Brook, Helena River, Henley Brook, Jane Brook, St Leonards Creek, Susannah Brook (Swan River) and Southern River/ Wungong Brook (Canning River). Toby Inlet – Quindalup Townsite. Vasse-Wonnerup Estuaries, Broadwater and New River - Busselton Townsite. For further information on flooding and floodplain management in Western Australia please refer to our Water Facts publications: Flooding in Western Australia (Water facts 13) and Floodplain Management (Water facts 14). This information is available at the Department of Water and Environmental Regulation's website at the following address: http://www.water.wa.gov.au/Publications/Find+a+publication/default.aspx - Under 'Find a publication' click on 'Series Browse' (3rd column from the left) and scroll DWERn to 'Water Facts' and select '+' button located on the right of the heading to open the PDF's Glossary: Annual exceedance probability (AEP) - the likelihood of occurance of a flood of a given size or larger in any one year; usually expressed as a percentage. 1 in 100 AEP flood - this means that there is a 1 in 100 (or 1%) chance of a flow of this size or larger occurring in any one year. This flood has a 50% chance of being experienced at least once in a person's life time. The 1 in 100 AEP flood has been generally adopted in Australia and overseas as the basis for floodplain management planning. Flood fringe - the area of the floodplain, outside of the floodway where development could be permitted provided it is compatible with flood hazard and building conditions provide an adequate level of flood protection. These areas are generally covered by still or very slowly moving waters during a 1 in 100 (1%) AEP flood. Floodplain - the portion of a river valley next to the river channel which is covered with water when the rier overflows its banks during major river flows. The term also applies to land adjacent to estauries which is subject to flooding. Floodway - the river channel and a portion of the floodplain where a significant flow or storage of water occurs during floods. If the floodway is even partially blocked then the natural flooding regime of th area may be detrimentally impacted with flood levels being raised and affecting areas which may not have been previously affected. Development in floodways is to be avoided wherever possible. Australian Height Datum (AHD) - is a geodetic datum for altitude measurement in Australia. It was adopted in 1971 by the National Mapping Council as the datum to which all vertical control for mapping is to be referred. The datum is based on the mean sea level (1966-1968) being assigned the value 0.000m on the Australian Height Datum (AHD) at 30 tide gauges around the coast of the Australian continent.

Seven flooding precincts have been identified around the lagoon foreshore. These have been sub-divided into four management areas. These management areas have been classified for flood hazard as: High Hazard - Floodways - Avoca Lagoon beach berm; - Saltwater Creek, from the upstream study boundary to its confluence with Avoca Lagoon (identified as Saltwater Creek floodway); and High Hazard – Low Hazard Floodway (Floodway Investigation area) - Avoca Lagoon at its entrance to the ocean (Floodway/Investigation area); Low Hazard - Flood Storage - Avoca Lagoon and foreshores excepting high hazard areas above. These management areas are illustrated on Figure 2, while Figure 3 provides more detailed information for the Avoca Lagoon entrance area and Figure 4 tables the specific provisions applicable to each of the management areas. Council has adopted a policy of opening the lagoons when water level reaches RL 2.09 m AHD (identified as the let-out-level). Council has, in the past, also adopted a policy that requires new buildings to have floor levels above RL 3.7 m AHD. These two policies effectively constitute Council's current floodplain management practice around Avoca Lagoon. Specific components of the Floodplain Management Plan are outlined in the report

The objective of the study was to undertake a detailed flood study of the local overland flow\r catchments of Raymond Terrace and establish models as necessary for design flood level prediction.\r In completing the flood study, the following activities were undertaken:\r • Collation of database of historical flood information for the LT Creek catchment including data\r from the June 2007 event;\r • Consultation with the community to acquire historical flood information;\r • Development of a hydrological model (using RAFTS-XP software) and hydraulic model (using\r TUFLOW software) to simulate flood behaviour in the catchment;\r • Calibration of the developed models using the available June 2007 flood data;\r • Prediction of design flood conditions in the catchments and production of design flood mapping\r series.\r Design events were considered with both a high and low Hunter River tailwater condition of 3.1m\r AHD and 1.1m AHD respectively. It is recommended to adopt the design flood levels derived from the\r higher tailwater elevation (3.1m AHD) for flood planning purposes, given higher peak flood levels\r derived in the catchment.\r In simulating the design flood conditions for the local catchments in the study area, the following\r locations were identified as potential problem areas in relation to flood inundation extent and property\r affected:\r • Colonial Motel (Adelaide Street) – the existing ground levels within this property are below the\r surrounding natural surface and accordingly when the stormwater drainage system capacity is\r exceeded, overland flow across Adelaide Street enters the property (the Adelaide Street/Colonial\r Motel Catchment Study (BMT WBM 2010) incorporated potential solutions to this flooding issue).\r • Centro car park – the car park lies on the natural overland flow path. Flood levels from local\r catchment runoff are exacerbated by the embankment created by Port Stephens Street which is\r elevated well above the low point in the car park (also addressed in BMT WBM (2010)).\r • Bourke Street/Big W car park – this area also forms a low point in the local catchment (and\r subsequent flood storage area) with the elevated Port Stephens forming a barrier to overland\r flows. Flooding is exacerbated when Hunter River water levels are high, and the stormwater\r drainage and pumping systems are ineffective in draining the local catchment runoff.\r • Irrawang Street/Johnson Close –local depressions in this locality result in inundation of private\r properties when stormwater drainage capacity is exceeded.\r • Closure of William Bailey Street – the low point along this route between the Port Stephens\r Street roundabout and the southern approach to Fitzgerald Bridge is around 1.4m AHD. Closure\r of the road would be expected when discharge of local catchment drainage is limited by high Hunter River levels as experienced in June 2007. Upgrades to the existing Kangaroo Street\r pump system may alleviate these road closure problems.\r A positive aspect of the simulated design flood conditions is the performance of drainage system\r upgrade works recently constructed for Adelaide Street/Bourke Street. The pipe augmentations and\r detention basin provide effective mitigation of local flooding problems that had been previously\r experienced, including the June 2007 event.\r As highlighted throughout this document, the capacity and arrangements of the existing flood relief\r pump stations are inadequate to provide effective conveyance of floodwaters derived from local\r catchment flood events coinciding with elevated Hunter River water levels. With more effective\r pumping stations, the extents and depth of flooding may be substantially reduced in the lower\r floodplain areas, thereby reducing potential damages to affected property. It is envisaged that\r pumping system upgrades will be a key consideration in formulating a floodplain management\r strategy for addressing overland flooding issues in Raymond Terrace.\r It is also noted that relative impacts of local overland flooding are far outweighed by mainstream\r Hunter River flooding. For Hunter River flood events overtopping the levee protection system, the\r magnitude and extent of flooding are significantly more severe than the overland flooding of the same\r design event magnitude.\r The flood study will form the basis for the subsequent floodplain risk management activities, being the\r next stage of the floodplain management process.

We identified opportunities to mitigate riverine flooding, estimating watershed response sensitivity and the potential scope of conservation intervention required for 70 cities in Latin America. Watershed sensitivity to flooding was based on physical watershed characteristics selected from a literature review and includes: watershed shape (roundness), slope, size, drainage density, and sensitivity of flooding due to standardized changes in discharge. Scope of intervention was based on six indicators that represent availability of restoration and preservation activities that mitigate flooding. Activities included: preserving or increasing infiltration, preserving effective pervious area, disconnecting effective impervious area, and preserving or increasing wetland and floodplain storage.

This dataset has been produced as part of the Mapping Potential for Working with Natural Processes research project (SC150005). The project created a toolbox of mapped data and methods which enable operational staff in England to identify potential locations for Working with Natural Processes (WWNP).

Data has been produced for each intervention covered by the project. The final outputs include the following datasets: • Floodplain Woodland Planting Potential • Riparian Woodland Planting Potential • Wider Catchment Woodland • Floodplain Reconnection Potential • Runoff Attenuation Features 3.3% AEP • Runoff Attenuation Features 1% AEP • Woodland Constraints

Runoff Attenuation Features Potential is our best estimate of locations of high flow accumulation across the land surface or in smaller channels, where it may be possible to temporarily store water and attenuate flooding during high flows. The dataset is designed to support signposting of areas to target enhanced storage. It is based upon the Risk of Flooding from Surface Water datasets and identifies areas of high flow accumulations for the 3.3% Annual Exceedance Probability surface water maps. The areas of ponding or accumulation are between 100 and 5000 metres squared, and have been tagged where they fall on an area of slope steeper than 6% as gully blocking opportunities. All the potential areas have been constrained so that they are not in urban areas or on roads, rails or canals.

The data does not does not provide information on design, which may need to consider issues such as drain-down between flood events. It is important to note that land ownership and change to flood risk have not been considered. Locations identified may have more recent building or land use than available.

Further information on the Working with Natural Processes project, including a mapping user guide, can be found in the reports published here:

https://www.gov.uk/government/publications/working-with-natural-processes-to-reduce-flood-risk Attribution statement: © Environment Agency copyright and/or database right 2015. All rights reserved.

Examined extent of the areas inundated by floods on bodies of water of the second order in the urban area of ​​the state capital of Dresden (valid version from January 2014). The presentation summarizes the state of knowledge on the maximum extent of the flooding caused by the flood event in June 2013. The illustration does not include flooding in the area where waters of the second order flow into the Elbe. These areas are shown in the areas flooded by the Elbe, since the flooding there was largely caused by the Elbe. The floods at the Lockwitz-Mühlgraben are also not shown, as these were mainly caused by the Lockwitzbach and are therefore shown in the Lockwitzbach floodplain. Furthermore, the storage areas of the flood retention basins, with the exception of the Weixdorf forest bath (because of its double function as a bath), are not included in the presentation.