Flood Mapping

[GarethRiley]

Hi,

Can anyone suggest a method or point me in the direction of a guide to creating a flood map? I have created them in the past but it's been a while.

I know I need a DTM, and I think I had to look at flow direction and accumulation? I'm not sure if this is what I should be looking at?

http://www.arcgis.com/home/item.html?id=bebbfc44c1724d9da0d41039cf4706df‌

Thanks

[wusirui]

Hello

I suggest that you could search some scientific papers and decide one direction that you want to work with. It is hard to say how does flood map can be defined. That is, You need to know what you need and how to get it.  You could search related scientific papers in Google scholar and may get some ideas about how you can get your flood maps. In my opinion, Flood map refers to many directions and points, such as how we can define Flood map? how flood map can be mapped and how we can measure this flooding. So, just get this macro principle and then you will know what kinds of process you need to work with.

Of course DEM data, flow direction and accumulation and stream network should be very helpful. Also, there were many tiny but important things during your processing, For example, How can you define your accumulation threshold and why this is important?

So, read more papers and then you could focus on your technique part.

[Anonymous User]

Hi Gareth,

As Wu suggested this is highly specialized stuff, on which many scholars and scientists break their heads.

At SIGGIS in Brussels, we recently integrated waterinfo.be. This is a flooding (and drought) portal for Flanders, the northern part of Belgium. The site displays a.o. predicted flooding contours, but these are made by highly specialized calculations models (a.o. Floodworks). These models take into account many variables, like measured precipitation, predicted precipitation, DTM, soils, soil saturation, surface resistance, subsurface flow, capillary rise, evapotranspiration, … and probably several other parameters. Per basin it takes up to 2 hours to run a calculation.

It is also key to note, that climate and geography will have a very profound impact on the structure and details of prediction models. It is hard to just copy a flood prediction model from one site to another. However the documents you’ll find on Google will explain you the basics.

Best you extend your research to local universities with a geography/hydrography department. Alternatively you can try to contact your local government agency that is dealing with floods. Both should have already some ideas on how local floods are predicted, if not, than you might have found a gap in the market (and call me ;-)).

Good luck!

[LauriYoung]

Hi Gareth,

FEMA shared a session focused on flood modeling: https://training.fema.gov/EMIWeb/edu/docs/hrm/Session%206%20-%20Modeling%20Flood%20Hazards.pdf

It does a good job of parsing out the components of a model. As others have already said, it is specialized and often proprietary (e.g. for Insurers).  Some scientists at Esri such as Dean Djokic might be a good connection for you.  Send me a personal message if you need an introduction.

- lauri‌

[BradyBernhart]

I noticed the National Weather Service website has a rivers and lakes link that shows close to real time data for stream flow at various monitoring stations.  I was looking at the Denver area, but should be available in other places.    

[curtvprice]

That's USGS data! NOAA/NWS is one of our cooperators, who along with other local, regional, state, and Federal agencies keep the data coming.

WaterWatch - Streamflow conditions