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FAQs for Flood Hazard Mapping Website

Questions

1. What is the purpose of the Flood Hazard Mapping website?
2. What does the Flood Hazard Mapping website show?
3. What are the symbols on the Flood Maps and what do they mean?
4. Who uses the Flood Maps information and what for?
5. What is the difference between General Users and Registered Users?
6. Can I become a Registered User of the Flood Hazard Mapping website?
7. Can I obtain a copy of the Flood Map data?
8. Where does the flooding information come from?
9. How complete are the Flood Maps?
10. How accurate is the data on flooding?
11. Are the Flood Maps reliable?
12. What is the meaning of the Quality Codes?
13. When are the Flood Maps updated?
14. Do the Flood Maps take into account any flood defence works or alleviation schemes?
15. I would like general information about areas vulnerable to flooding.
16. Can the website show me if my house is at risk of flooding?
17. My house is shown inside a flood boundary but has never flooded.
18. I know that an area has flooded but it is not shown on your maps. Can you update the website?
19. I am worried about proposed development in my area where I know that flooding occurs. Who do I contact about this?
20. What is the OPW doing about flooding in my area?
21. I am having problems: The map does not appear in the screen but every thing else seems to work, all I have is a red X in the top left corner of the map window.
22. I am having problems: I can see the main map but none of the map controls seem to work - the map will not zoom in or out or pan.
23. I am having problems: The website returned to the opening screen in mid-session.

Answers

1. What is the purpose of the Flood Hazard Mapping website?

The Flood Hazard Mapping website provides information about the location of known flood events in Ireland and shows supporting information in the form of reports, photos and press articles about those floods. The main purpose is to provide flooding information to the public and to Planning Authorities, developers and engineers around the country. This will help citizens and planners to make informed decisions to better prepare against existing flood risk and to avoid creating new risk such as could arise through inappropriate building in floodplains.

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2. What does the Flood Hazard Mapping website show?

The website is divided into three areas: the Map Window, the Search Panel and the Results Panel. The location of flood information is shown in the Map Window with maps of Ireland at different scales and other layers of related data, such as Rivers, Lakes, Hydrometric Stations, Land Commission areas, Drainage Districts and Benefiting Lands. The Map Window has Tools to allow you to zoom into an area, turn on and off the different layers of information and select Flood Event information. The Results Panel displays text information about selected Flood Events and has links to additional information, such as photos, flood reports, press articles and other mapped information. The Search Panel enables you to search for flood information by selecting specific locations and/or dates.

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3. What are the symbols on the Flood Maps and what do they mean?

Floods are represented on the map in three different ways. Where the boundary of a flood has been mapped, the flood is shown as a shaded area Region Flood with a blue border defining the extent of the flood. Most floods cannot be shown in this way because the extent of the flood was not mapped at the time. Therefore, floods without extent information are represented with a point symbol Flood placed at the approximate location of the flood. A flood point symbol is placed at any location mentioned in a report giving details of a flood event. Where more than one flood has occurred in the same location, and to denote a location with recurring flooding, a multiple flood point symbol is used Recurring Flood.

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4. Who uses the Flood Maps information and what for?

The Web site (http://www.floodmaps.ie) is aimed at three target audiences, who have concerns about flooding
        - ordinary citizens
        - developers and engineers
        - other stakeholders, in particular, the professional Local Authority planners who have responsibility for decisions relating to spatial planning and development management.
The Flood Maps information allows planners to give full consideration to flood risk issues when assessing planning applications and when preparing spatial plans, such as Development Plans. To the general public, www.floodmaps.ie raises the general awareness of the risk to property and possibly life from flooding in Ireland. Further information about flooding is also available at www.flooding.ie  

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5. What is the difference between General Users and Registered Users?

There are two methods of access to the Flood Hazard Mapping website: General User access and Registered User access. The same types of information are available to both user groups. However, because of restrictions imposed by some source bodies, and due to certain equipment specification requirements, certain features can be accessed only by Registered Users. Registered Users are generally state bodies, such as the local authorities, who provided material for the website. In addition to viewing the flood information, Registered Users are allowed to download data from the website, save a full reports on a flood in pdf format and view the maps without the watermark image.

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6. Can I become a Registered User of the Flood Hazard Mapping website?

It is not necessary to be a Registered User of the website in order to view flooding information. All General Users can search for, view and download reports about flooding events in Ireland. Only users within local authorities and other state bodies can become Registered Users and can download data from the map layers. Private individuals and commercial users may not become Registered Users.

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7. Can I obtain a copy of the Flood Map data?

It is possible to generate a summary report of flood events from the Map Window by clicking on the Map Report option below the map and then following the link to the Summary Report. In addition, when viewing reports and press articles, you have the option to save a copy to your local computer. Other than this, it is not possible for General Users to obtain copies of the Flood Map data. The database of flood events and report information is very large and complex and not suitable for distribution to individuals. Registered Users may download mapped flood information on a County basis.

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8. Where does the flooding information come from?

During the two years (2004-2006) that the website was developed, a huge data collection program was undertaken, visiting over 50 organisations (mainly local authorities and national organisations, eg Waterways Ireland, DoEHLG, Teagasc) to collect and collate a vast array of information about flooding. The type of information varied from photographs of flood events, to consultants' reports, recordings from gauging stations, eyewitness accounts from staff plus letters from members of the public and minutes of meetings with key officials. All this information was reviewed, verified, assessed and catalogued to create a National Flood Data Archive. From this the flood maps were created and uploaded to the website. Since 2006, as flood events occur or as information is submitted to OPW from different sources, including information from the public, new flood symbols and reports are being added to the website on an ongoing basis.

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9. How complete are the Flood Maps?

The National Flood Data Archive is not a comprehensive catalogue of all past (fluvial/tidal) flood events in Ireland; material was presented for inclusion by source bodies from their available records at their discretion. However, the Archive is still the most comprehensive and complete collection of data on past flood events available in the country. New information is verified and checked for duplication before addition to the archive.

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10. How accurate is the data on flooding?

All the information presented in the Flood Hazard Mapping website has been verified and classified according to the quality of the content. Flood points and areas have been mapped to the best available information describing their location and have also been classified according to the quality of the supporting report information. The quality codes used to classify the flood information are described in Question 12 below and in the Glossary section of the website. The presence of a flood point symbol is only indicative of the approximate location of a flood and is not expected to be accurate to the level of individual properties. Similarly, flood extent boundaries indicate that flooding has been recorded in that location but individual properties within, or adjacent to, these areas may not have flooded in the past or may not be at risk of future flooding due to local conditions e.g. elevated floor levels, individual flood protection measures or other such reasons. The absence of a flood indicator (point or area symbol) for a past flood event in any particular location does not mean that flooding has never occurred in that area nor does it mean that that area may not be liable to flooding in future. A location may be at risk from flooding but information on past floods at that location may not be available.

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11. Are the Flood Maps reliable?

The reliability of all the flood information (with the exception of the press articles) is assessed as part of the verification process and is reflected in the quality codes (see following question) assigned to both the flood events and flood reports. The highest quality code (1) is assigned to the most detailed information about a flood (including the peak time and levels, dates, known locations, engineers reports, and so on). Where information is of lower quality (such as approximate dates, peak times not known, levels not recorded, location estimated) a lower quality code is assigned. In this way, the reliability of the information can be assessed.

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12. What is the meaning of the Quality Codes?

The Quality Codes are used to classify the flood event and report information according to the reliability and content of the information. The definitions of the codes are as follows: Code 1. Contains, for a given flood event at a given location, reliably sourced definitive information on peak flood levels and/or maximum flood extents. Code 2. Contains, for a given flood event at a given location, reliably sourced definitive information on flood levels and/or flood extents. It does not however fully describe the extent of the event at the location. Code 3. Contains, for a given location, information that, beyond reasonable doubt, a flood has occurred in the vicinity. Code 4. Contains flood information that, insofar as it has been possible to establish, is probably true.

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13. When are the Flood Maps updated?

The National Flood Data Archive, which provides all the information for presentation on the website, is continually being updated and added to by the OPW. Information on new and past flood events can be, and is, submitted from a variety of sources (government, private and individuals) for inclusion as it becomes available. All information is checked and classified first, then approved before it appears on the website. Important new additions, and any changes to the website, will be reported on the News/Updates page.

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14. Do the Flood Maps take into account any flood defence works or alleviation schemes?

Changes may have occurred that have impacted positively or negatively on the flood susceptibility at a particular location where there are flood indicators shown on the Flood Map. Positive impact developments would include the carrying out of Catchment Drainage schemes or flood relief works, while negative impact may result from construction in nearby flood plains etc. Where possible, and if these impacts are known, changes have been made to the quality code of flood events to reflect their present day relevance. The presence of major changes will have the effect of reducing the quality code of the event e.g. from Code 1 to Code 2. The location of flood defences and relief works are not shown as separate layers on the Flood Maps.

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15. I would like general information about areas vulnerable to flooding.

The National Flood Data Archive is a record of historical flood events collected for presentation on the Flood Hazard Mapping website. This is the first phase of the OPW's National Flood Hazard Mapping Programme. In the second phase, which is ongoing from 2007 until 2013, OPW will generate predictive flood maps as part of the Catchment Flood Risk Assessment and Management Studies. Predictive Flood Maps will show the vulnerability of areas to flooding of different intensities. These maps will be displayed on the website as they become available. Because of the complexity of these studies this programme will take a number of years to complete. Pending the availability of predictive maps, the historic maps will provide planners (and other users) with an indication of where flood risk should be considered.

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16. Can the website show me if my house is at risk of flooding?

The Flood Maps show the location, and in some areas the extent, of known historical flood events. The presence of these flood symbols on the map in any given area is indicative of a risk of flooding but individual properties may not have flooded in the past or may not be at risk of future flooding due to local conditions e.g. elevated floor levels, individual flood protection measures or other such reasons. Additional flood protection measures may also have been developed to reduce the risk of flooding since an event took place. Once Predictive Flood Maps are available, these will show the areas predicted to flood for an event of a given magnitude, eg. a 1 in 100 year event. These Predictive Flood Maps are currently being generated by the OPW on a catchment by catchment basis and will be added to the Flood Maps website in due course.

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17. My house is shown inside a flood boundary but has never flooded.

The Flood Maps show the location, and in some area the extent, of known historical flood events. The presence of these flood symbols on the map in any given area is indicative of a risk of flooding but individual properties may not have flooded in the past or may not be at risk of future flooding due to local conditions e.g. elevated floor levels, individual flood protection measures or other such reasons. Additional flood protection measures may also have been developed to reduce the risk of flooding since an event took place.

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18. I know that an area has flooded but it is not shown on your maps. Can you update the website?

The OPW welcomes any additional information on known flood events to add to the National Flood Archive. Information in the form of photographs and reports, preferably containing details of dates, times, locations and levels, can be forwarded to the OPW using the Feedback option on the website (email fhmfeedback@opw.ie), or by sending material to local OPW offices. All new information is verified and classified by local OPW staff before addition to the website. Further information on flood data collection and what is useful flood data can be found on the following web page Flood Data Collection. If you disagree with information shown on the Flood Maps, OPW welcomes any such feedback and will investigate individual cases. However, please be aware of the limitations and guidelines associated with the website and the data shown; particularly that the Floods Maps are a general guide and not intended to be accurate at the level of individual properties. All information shown has been through a rigorous and thorough checking procedure and is classified accordingly. It may not be possible to change the data shown if it is deemed to be an accurate representation of the available information for that flood.

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19. I am worried about proposed development in my area where I know that flooding occurs. Who do I contact about this?

The main objective of the National Flood Hazard Mapping website is to provide information to the public and to Planning Authorities on flood risk at locations around the country. This will help citizens and planners to make informed decisions to better prepare against existing risk and to avoid creating new risk. The National Flood Archive, on which the website is based, is the most comprehensive source of historical flooding information in Ireland, making the website the best single source of data available on flood risk. If you have additional information about a known flood event which is not shown on the Flood Maps website, then please forward that information to OPW via the Feedback link (email fhmfeedback@opw.ie). If you have particular concerns about a proposed development, please contact your local Planning Department.

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20. What is the OPW doing about flooding in my area?

In September 2004, the Government approved the Report of the Flood Policy Review Group, naming the Office of Public Works as the lead agency for flood risk management in Ireland. In fulfilling this role, the OPW is undertaking a Flood Risk Assessment and Management Programme for all river catchments in Ireland. These studies assess the level of flood risk throughout each catchment, through the creation of detailed computer models of the rivers and their floodplains, and the development of predictive flood extent maps. From these, strategic plans for managing the flood risk for the catchment are developed, called Catchment Flood Risk Management Plans. Pilot studies are already underway for the Lee, Dodder and Suir catchments. The OPW is also responsible for the national Arterial Drainage Maintenance Programme, which maintains the 34 arterial drainage schemes constructed under the 1945 Arterial Drainage Act, benefiting a total of over 650,000 acres of land. In addition to this, the OPW designs, commissions and maintains certified drainage schemes for localised urban areas under the 1995 Amendment Act. Since 1995, 13 schemes have been built, including Kilkenny, Cappamore, Sixmilebridge, Duleek, Gort and Maam. A similar number of schemes are currently at Feasibility, Design or Construction stage. The OPW provide advice in the consideration of flood risk in Planning and Development Control, and in the construction of river-crossings, through the Section 50 Consent required for new bridges and culverts.

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21. I am having problems: The map does not appear in the screen but every thing else seems to work, all I have is a red X in the top left corner of the map window.

If you are unable to see a map in the map window, please check that you are using one of the following browser versions: " Internet Explorer, versions 5.5 and later " Netscape, version 7.0 and later " Mozilla, version 1.0 and later If you are using one of these browsers but still cannot see the map, try refreshing the page or restarting the browser and re-entering the website. If you are still unable to view the map, this may be because of personal firewall settings or other security software running on your computer. For further information please contact us through the fhmfeedback@opw.ie email.

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22. I am having problems: I can see the main map but none of the map controls seem to work - the map will not zoom in or out or pan.

In order for the map controls to work properly, you must have Javascript enabled in your browser. For instructions on enabling Javascript, please click on How to enable Javascript Please also ensure that the pop-up blocker is disabled when using the FHM website.

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23. The website returned to the opening screen in mid-session.

The website will timeout and return to the opening screen after a period of inactivity of 20 minutes or longer. You will need to re-enter the site to continue.

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