Questions tagged [hydrology]

The study of the movement, distribution, and quality of water on Earth and other planets, including the hydrologic cycle, water resources and environmental watershed sustainability.

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2k views

Automatically generating pour points along stream network?

The following screenshot shows the results of a water flow analysis where I identified stream order via the Strahler method in ArcGIS. Now I need to generate watersheds for 2nd order streams and ...
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1answer
52 views

How to find out which areas are affected by flooding due to heavy rain?

I'm working on a little project to visualize affected streets of flooding due to heavy rain. I already got a DEM for my study area and filled the depressions with r.fill.dir. Since I never worked on ...
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How do I determine the correct ratio to peak value for the Recession baseflow in HEC-HMS?

I am wondering if there is a way to estimate the ratio to peak value without calibration? What would be the most suitable value if I don't have a measured hydrograph to compare? Thanks for any ...
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D8 algorithm to get flow direction in ArcGIS Desktop

I am using ArcGIS 10 for the get the flow direction from DEM. I wonder about the algorithm they have used while calculating flow direction. It is mentioned there that it is using D8 model. D8 model ...
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TauDEM: How to extract the longest flow path from an outlet to the basin divide as a shapefile

Using TauDEM I've created a number of derived raster products from an initial 30m SRTM DEM with a statewide (South Carolina) extent. Using the D8 modelling methods, I've created both the D8 Flow ...
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TauDEM fails to create stream network shapefile (-net option) when running StreamNet method on Ubuntu

When I try running TauDEM's "StreamNet" method including the optional -net flag to create the stream links / channel network as a shapefile, it fails with a lot of errors like: ERROR 10: ...
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How to aggregate properly 8-days MODIS ET to a monthly ET?

I am looking for a robust method to aggregate the 8-day MOD16A2 (or MOD16A2GF) ET_500m values to monthly ET. Since ET_500m and PET_500m, are the summation of 8-day total water loss (0.1 kg/m2/8day). I ...
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QGIS: How do I combine/summarize information from several attributes to one specific attribute?

I have a pretty specific question and I dont know how to approach this. I have a polygon layer for subbasins in the Danube area (HydroShed) which also contains information for water discharge. The ...
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2answers
152 views

Isochrone along direction map of watershed

I am interested in producing a isochrone map given a raster speed map and a direction map (like the output of r.watershed), but I do not see how to produce it. I have studied r.walk and r.cost wich ...
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How to interpret the Maximum flow path length raster, from the SAGA Maximum flow path length tool

Does anyone know how to interpret the Maximum flow path length raster, after running the SAGA Maximum flow path length tool? I have used this tool and received a raster but I'm not sure how I can get ...
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43 views

Cascading order of basins (next downstream basin) in QGIS, R, or Whiteboxtools

I am conducting a hydrologic analysis of DEMs. Suppose that I have the following basins in an area as shown below:. I need to get the cascading order of each of the basins. In other words, I need to ...
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Catchment area raster values

In order to calculate TWI, I had to generate a catchment area raster, but I don't understand what the values of pixel represent. Any clarification? The DEM is projeted in EPSG : 2154, so the unit is ...
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115 views

Selecting or highlighting upstream elements

I would like to use the information from the Swedish SMHI related with their hydrological model elements (catchment areas) that have a Containment hierarchy structure, each element has the information ...
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1answer
57 views

How to automate flooded area calculation and make report using PyQgis?

I have 3 shapefiles with me. They are a flooded layer, District layer and Village layer. To estimate flooding village wise, I have to do intersecting the features and get the layer. Then I calculate ...
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Water direction and intensity of superficial flow

I'm working on maps that the goal is: to display the direction and intensity of surface water flow. I have the DEM for the watershed and generated the direction of flow, but I don't know how to ...
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1answer
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QGIS: Burning stream network (catchment area)

I need help from stackexchange because of a DEM correction problem... I have a DEM with a 5 meters resolution where one of the main river is cut by a large highway. In order to delete that topology ...
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1answer
57 views

GEE: masking for multiple pixel values

The GEE tutorial shows how to mask an image for one pixel value using .eq(pixel value). However, I want to mask all pixels in an image with a value of 15 or less in this dataset var riverflow = ee....
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Watershed delineation using hydrological Python library

We would like to delineate watershed polygon for a given pour point using hydrological Python library. Until now, we have tried these libraries: pyshed Grass (r.watershed) Whitetoolbox We have ...
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Get catchment area of a lake polygon in R

I have several DEMs as geotiff files which I load into R using raster::raster. Additionally, I have lake outlines (located within the DEMs) in the form of shapefiles which I load into R using raster::...
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1answer
311 views

Curve Number equation in ArcGIS Raster Calculator?

I have a floating point raster of Curve Numbers (70-91) and I'm attempting to use the curve number equation to create a weight raster for flow accumulation, to determine runoff for a single rainfall ...
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18 views

Add buildings contours to DGM for hydraulic analysis [duplicate]

I use Hydrology Terrain Analysis Tools in QGIS/ArcGis. Now i try to add some building contours to my DEM. I got building Data (Polygons) and a Raster DEM. Finally i want the buildings added to my DEM, ...
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Why am I getting a straight flow path (stream) in obviously varying terrain -QGIS

Does anyone have suggestions on why the streams are sometimes represented as longer straight lines, even though the hillshade and contours generated from the same DTM (filled) clearly indicate that ...
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1answer
58 views

Optimizing pixel extraction from GeoTiff using Python

I am creating IDF Curves for work using python and 30-minute rainfall rate rasters. There are 24 rasters per day and about two decades worth of data. I basically input lat/lon coordinates and my ...
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3answers
2k views

How to display Flow Direction arrows + Burn Stream Netwok in QGIS?

I have used the automated r.watershed tool in QGIS 2.18 (GRASS plugin) to conduct a watershed analysis (basin boundaries, flow direction, flow accumulation etc). I'm stuck on the following operations:...
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1answer
107 views

Apply volumes to points on a raster DEM in QGIS

I am trying to create a flood inundation map in QGIS from known flood volumes at specific points across a raster DEM. I could potentially do this manually for each individual point using contours ...
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1answer
88 views

Identify main inlet of a lake in ArcGIS

I'm trying to figure out an automated way to identify mountainslopes from where a rockfall could hit lakes using the hydrological tools of ArcGIS 10.7. As rockfalls do not behave like runoff water, ...
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Urban runoff volume calculation

I was wondering if someone could help me out on how to calculate runoff volume within an urban area ? I have already produced different outputs: Filled DEM Catchment area Channel network flow ...
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4answers
127 views

Seeking free software for rain catchment area?

I want to be able to calculate the catchment area that would feed rainwater into proposed swales. I can do this easily enough, and with sufficient accuracy--not much accuracy is really needed, on a ...
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22 views

Monthly albedo data for VIC

I am trying to download Albedo data for my research area. On NASA's Earthdata website I used the MODIS product MCD43A3,. First reason why I haven't downloaded the data is because my research period is ...
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608 views

Problem in running r.sim.water

I am trying to run the r.sim.water in GRASS. I have calculated the partial derivatives dx and dy rater map using r.slope.aspect. I am using this elevation map [1] to get the time-series depth map. But ...
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2answers
4k views

Flow Accumulation in R [closed]

Is there an ArcGIS-like implementation of Flow Accumulation for R? What I am trying to avoid: Using ArcGIS; Using Grass; Using RpyGEO (but will if need be) I am aware of the landscape/hydrology ...
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2answers
68 views

Fill a sink with a known volume of water to obtain actual depth and extent of a pond

Using ArcMap 10.7 I have a raster with sinks in a terrain that I developed by processing a DEM dataset. Each sink has been delimited and turned into a polygon too, and its total volume was ...
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1answer
60 views

Creating flood inundation map from watermark QGIS

I have a high water elevation for a location and I want to subtract this elevation by the DEM raster to achieve a water depth raster, and I am not sure how to go about this. I am assuming a constant ...
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1answer
54 views

Population in upstream area (looping over FeatureCollection)

I want to calculate the sum of the population living in the upstream area of stations using the hydro package by gena. I think I will have to loop over the stations (using the identifier "GEMS_Stati")....
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1answer
72 views

Changing lakebed symbology to relative depth in ArcGIS 10.5 (TIN or raster file)

I have several TIN files representing empty lakebeds at altitudes ranging from 5000m to 3000m. I have calculated the TINs using ArcGIS hydrology tools and an ASTER v3 DEM projected to ...
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2answers
3k views

Calculating cells elevation (height) above nearest stream cell using ArcGIS Spatial Analyst

I have searched for some ideas on how to formulate this analysis, but have come up short. I imagine there is a pretty straight forward answer; any help would be greatly appreciates. Data: DEM, 1/...
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1answer
62 views

Calculating volume of several TINs in ArcGIS Desktop

I am trying to calculate the volume of several TINs using the 3D Analyst of ArcGIS 10.5. My data can be found here: https://drive.google.com/open?id=1ERFdsqDGLH1a_FbxwawE_gPm0Au0Q9vT For a start, I ...
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152 views

Get catchment delineation with multiple outlets in QGIS 3.4 or 3.8

I'm starting with a DEM, then I generate a drainage direction layer (ldd). Then I'm trying to get all the watershed basins for multiple outlet points in a QGIS plugin I'm developing. I can get them ...
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2answers
1k views

Can anyone point me to a dataset (shapefile or other format) for the North American Continental Divide?

I'm looking for a more detailed dataset than the 1:2,000,000 shapefile available from the National Atlas, preferably one suitable for use at 1:24,000.
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QGIS Grass 7 r.fill.dir

The following layers were not correctly generated.C:/Users/JIM/AppData/Local/Temp/processing_e2688a45d8934d16a2269a7ef6af8cbd/7eefcc8d13144f598fa7ab5bb5d657b8/output.tifYou can check the 'Log Messages ...
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32 views

Calculating the volume of multiple lakes with ArcGIS (3D Analyst)

I have the DEM of a glacier bed and want to calculate the volume of bed depressions that could form lakes. Data is available here: https://drive.google.com/open?id=1ERFdsqDGLH1a_FbxwawE_gPm0Au0Q9vT I'...
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36 views

Using ArcGIS to quantify sink volume in glacier bed (“sink” and “fill” tools)

I am trying to identify sinks/overdeepenings in glacier beds and quantify their volume. If you take a look at my data (https://drive.google.com/drive/folders/1ERFdsqDGLH1a_FbxwawE_gPm0Au0Q9vT?usp=...
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1answer
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How is “Burn Stream Slope” in ArcHydro working?

I have a DEM with only small relief and many ditches. Because of the small relief, I can't calculate flowdirections for some parts of my DEM. I know that in reality water is flowing from west to east (...
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2answers
964 views

QGIS: Saga Channel network: how to prepare SRTM data

I am trying to use the Saga toolbox (2.2.3) in QGIS (2.18) to create a channel network from SRTM data using this tutorial 1. It works, but the result I get when using the DEM that comes with the ...
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88 views

Calculating drainage density

How can I calculate drainage density in QGIS if I have length for stream and grid line 1 km2? I need to calculate density per km2.
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Create catchments/subbasins for specific nodes

I have an XPSWMM model of a neighborhood storm drainage system. Nearly all of the drainage is above ground through a network of ditches and culverts. I still need to create catchments for the ...
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1answer
42 views

Creating symbols between connecting lines to represent line boundaries

I am trying to figure out a way to create markers as seen from the attached image where an angled line (in dark red) is created between the lines to represent a connecting stream. With the data I am ...
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1answer
68 views

Quicker function than dissolve and difference

I'm on QGIS (v. 3.6) trying to create a map of Florida's hydrography using the NHD "Water Areas" shapefile. Methodology is to fix any invalid geometries in the NHD data, dissolve the layer, and then ...
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0answers
130 views

Vector map (rivers) to Raster. [ **ERROR 1: Wrong value for -outsize parameter.**]

I want to transform this vector map: To something like this I only tried to convert the vector map through Raster> Conversion> Rasterize But I get this Error: QGIS version: 3.6.3-Noosa QGIS code ...
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2answers
930 views

Correcting Errors in Height Above Nearest Drainage (HAND) model

I have used this tread Spatial Analysis - Calculate a cells elevation (height) above the nearest stream cell to create a HAND map in ArcGIS. First I used the hydrology toolset to fill in sink in the ...

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