# Questions tagged [flood]

A flood is an overflow of water that submerges land which is usually dry. Within GIS we often want to model a flood with terrain models.

26 questions with no upvoted or accepted answers
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### Flood mapping in QGIS 2.4

I am trying to delineate flood-prone areas using QGIS. I have a vector layer of the river and a DEM of the same area. I have used the GRASS Module to get watershed by using r.watershed and I have ...
• 119
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### Creating cumulative friction map

I am looking at bottom friction (Manning's n) values in relation to storm surge as large volumes of water flow over a surface. In order to calculate total head loss occurring as water passes from the ...
197 views

### ArcGIS Calculate flooding area based on input amount of water

I have created a DEM based on historical maps from 1816. I'm supposed to calculate the flooded area for certain amounts of water (in m³/s). I intended to do it with ArcHydro - however, as far as I ...
• 21
392 views

### Multicriteria Analysis for flood risk analysis

I have used a multi-criteria analysis which uses factor weighting for flood risk identification in a river basin using ArcGIS 10.1. My factors are rainfall, drainage, density, slope, and land use. ...
1 vote
21 views

### Urban watershed delineation for flash flood events

I am currently trying to create urban watersheds using the ending points of flash flood events (in the NOAA Storm Events Database) as outlet points for a city. While doing so, the watershed that is ...
1 vote
52 views

### How do I calculate high water extents?

Could someone suggest the right path to follow if I were looking to calculate the high water extents or potential flooding that could occur on a tidal river. I am working in ArcGIS Pro and have ...
• 11
1 vote
49 views

### How to check hydrological connectivity in flood fill techniques in QGIS?

I have a set of polygons (include their elevation levels), representing geographical areas. I want to check which polygons will be inundated if a flat flood level is given. Lets say 1m flood from sea ...
1 vote
117 views

### How do I "flood" a terrain in Cesium to represent a high water level

I am thinking about using a plane object to represent a water level by rendering it as a certain height above ground using Cesium. Is there any example code that
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1 vote
39 views

### Creating local copy of an online Potential Flood Inundation Map

I am completely stuck, usually I can figure out how to create a local copy of hosted services, but this one I can't seem to get anything to work and any suggestions would be great. Currently I can ...
1 vote
356 views

### GRASS GIS: Time series of overland flow from r.sim.water

I am trying to perform an overland flow routing on a large area using r.sim.water in GRASS GIS. I've looked at other answers and made sure to set my computational region to the elevation raster I'm ...
1 vote
58 views

### Where can I obtain data on flood sites, land sewage systems, and property value?

I am a college student trying to obtain this data for a class project. If anyone can help that would be great. Basically, my hypothesis for this project is that land sewage systems that have not been ...
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1 vote
1k views

### How to make an inundation map?

My task is to calculate the area available for specific plant species in a natural reserve that has been reconnected to the tidal influence. First step is to create an inundation map for a natural ...
1 vote
100 views

### What is the background processing of rainfall thresholding?

I want to create a flood map using Quantum GIS. First of all I create catchment area (flow accumulation). Then, I delineate a Channel Network by applying a threshold to flow accumulation. So I want to ...
• 227
1 vote
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### flood mitigation

I would like to carry out flood mitigation using non-structural measures like wetland restoration, detention ponds and infiltration ditches or ponds. How can GIS help me in siting and visualizing the ...
10 views

### How to set up table for HAND based flood extents in ArcHydro?

I have a stream line and points with surface water elevation and a DEM of the watershed. I really liked the look of the HAND-based on Flood Depth and Extent but I would like to use the water elevation/...
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### How to combine vector data (census) with raster data (inundation)

I am hoping to find a way to create a map showing the overlap of flood inundation and social vulnerability in QGIS. I tried using zonal statistics, but it does not take into account the values, just ...
• 1
15 views

### Creating time series flood inundation map using NetCDF future sea level and DEM

I want to design a GIS tool that visualizes flood inundation maps for future sea level rise. the data that I need to use are NetCDF of projected Sea level rise for 10-year slices and DEM. The idea is ...
23 views

### Get output from this code

I get this error Error: Image. select: Pattern 'scale' did not match any bands. (Error code: 3) from this code. Map.centerObject(table); Map.addLayer(table); var before = ee.ImageCollection('...
59 views

### Creating a layer showing difference before/after flood (raster)

I ran a supervised classification on two satellite images - (i) before and (ii) after a flood. Now even before the floods, there were pre-existing water bodies which obviously don't count as flooded ...
34 views

### Should I re-scale all the dataset to one scale before running them into model?

I have been working on the Flood susceptibility modelling and also have identified, collected and generated data of around 26 controlling factors(indicators). Furthermore, i'm going to put them into ...
229 views

### Creating a Cross section of a river

I am using QGIS and HEC-RAS for my project. HEC-RAS needs a file for the river bathymetry. Since I do not have data for river bathymetry, I decided to use the Profile Tool in QGIS to create a river ...
156 views

### Raster manipulation in ArcGIS - Flood Mapping with HAND

I am trying to create flood maps using the height above nearest drainage (HAND) method using data from the continental flood inundation mapping (CFIM) project. I have the following data: A raster map ...
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108 views

### Measuring the intensity of raster pixels within buffers

I need to create a variable ranging between 0 and 1 to compute the intensity of a flood. I have the raster file for the flood and the layer with the coordinates of the households that have been ...
105 views

### Generating extent of 1 ft rise in floodplain using ArcMap

I have a polygon layer that represents the max inundation extent along a stream for the one-year storm event (generated in hec ras). If this floodplain was theoretically raised by one foot, what would ...
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