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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242 views

reading GRASS vector map in python

I know similar questions have been asked several times, but none of the solutions seems suitable for my problem or don't work.. I computed flowlines using the r.flow tool from GRASS GIS, then I ...
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544 views

How do I export a line shapefile from a network downstream from a point in ArcGIS 10.1?

I'm using the National Hydrological Dataset's flow lines to trace downstream movement of water is a freshwater diversion from the Mississippi river in Louisiana. I've gotten the trace to run using ...
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620 views

r.topidx error: required parameter output not set

I'm calling GRASS r.topidx from QGIS 2.2.0. I can get other tools to work on the DTM, for example r.watershed. But r.topidx I get the Oops message: Oooops! The following output layers could not be ...
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591 views

import parameters for r.watershed - (watershed basin analysis program) tool from grass using Qgis 2.2

I want to run this tool from Qgis 2.2 but i don't know how to use the PARAMETERS to run this tool. The red frame are the PARAMETERS I don't know. Can someone to tell me what those PARAMETERS are and ...
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56 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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114 views

GRASS Error: WARNING: segment zero_fill(): Unable to write (No space left on device)

I was trying to define the drainage patterns and to delineate some catchments based on a 30m DEM using r.watershed --overwrite elev=DEM accumulation=Accum drainage=Drainage -m but grass would ...
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1answer
290 views

Shifting entire river channel in HEC-RAS?

This question is specific to the HEC-RAS software. I'm trying to use the software to shift a river channel. I've used the Geometric Data Editor for the Cross Sections to edit the positions of the ...
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1answer
389 views

tauDEM flow accumulation (D8 or D-infinity) results is NA-values for some major rivers

I am having some trouble with tauDEM that I am hoping someone can give me some advice on. I'm running tauDEM via command line through R-studio. I am working with some 30m resolution SRTM DEM data in ...
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155 views

How to Create SCS (now NRCS) Curve Number Grid using GIS with European map (ESDAC dataset)?

After finishing the watershed delineation, and after creating the HMS schematic in Arcmap, i was trying to include the land use map and soil map in the process, by using the CNgrid preparation by ...
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33 views

Choose between two points with same name but different attributes in ArcGIS

I have a dataset of thousands of points, made by the intersection of flowlines with waterbody polygons. Each polygon has two (or sometimes more, if the waterbody has multiple tributaries) points made ...
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1answer
42 views

Find all polygons upstream of a set of points? [closed]

Given two datasets 1) polygons for global river basins and 2) points for global hydro power dams; how can I determine the upstream basins for each dam? Not sure where to start with this, looking for ...
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259 views

r.fill.dir blocked

I am trying to fille a DEM downloaded by Geobolivia http://geo.gob.bo/. The r.fill.dir module in QGIS/GRASS toolbox blocked few minutes after I launched it for the DEM. It is very strange as, for ...
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2k views

Explanation of HAND (height above nearest drainage) model procedure

i tried to follow this procedure Spatial Analysis - Calculate a cells elevation (height) above the nearest stream cell but i have some problem to understand everything. I mean the 2th answer in the ...
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1answer
5k views

Downloading Hec-GeoHMS for ArcGIS 10.3.1?

I can't download geohms from this link http://www.hec.usace.army.mil/software/hec-geohms/. Can anyone help me to get Hec-GeoHMS for ArcGIS 10.3.1? The doesnot responds and I could not get a Hec-...
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1answer
98 views

NDVI for natural region

I have remote sensing data which I have got from landsat 7. The area which I am working on is combination of farms and natural area (Bare earth; without any vegetation). I want to estimate the ...
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1answer
131 views

Discrete waterpoints with GRASS [closed]

I've been working with GRASS GIS for about two months. I have to develop a method for the identification of target regions of small hydropower plants. Boundary conditions are a predetermined minimum ...
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1answer
203 views

Urban Hydrology Using With GIS

I'm researching how can I create a model urban floodplain depending on rainfall. And Which programme should I use? I want to show floodplain depending on temporal and spatial distribution on study ...
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1answer
221 views

How are minor tributaries determined?

What are the criteria to determine if river A is a major or minor tributary to another River B? Is stream order the only deciding factor i.e. the highest order is the main stem, one less order is a ...
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1answer
53 views

1:250 streams data - USA wide - where can I find it?

I have 1:250 streams data for a few western states. I find this scale to be excellent in many settings as base hydro data. I have never been able to find a USA or better yet, NA wide dataset of this ...
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1answer
3k views

How to find Q in m3/sec from a raster having Q in mm for hydro power calculation

I am having a raster file with runoff depth Q in mm which was obtained from SCS method. I want to calculate hydro power potential at any location on my DEM. In the formula Q is in m3/s but we are ...
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13 views

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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14 views

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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29 views

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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17 views

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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78 views

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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1answer
45 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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19 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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23 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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182 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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0answers
39 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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92 views

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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37 views

Flow Distance Not Calculating for Entire Raster

I am trying to calculate the height above the nearest stream for an area. The problem is, it only does so for a portion ( the colored area below) of my area of interest. In the pic below, the black ...
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0answers
106 views

Howerive vector stream network from a DEM using D-Infinity Flow Direction algorithm?

I have been working with a 1m LiDAR derived DEM to create a vector stream network. Using the D8 flow direction, D8 flow accumulation, and a specified threshold, I was able to create a vector stream ...
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36 views

Is there a way to produce a line on a raster, which direction is based on cell values?

I am looking at a raster layer where each cell has one of 8 values, indicating where flow from the cell is directed. Is there a way to select any given cell, and have a line drawn which will follow ...
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1answer
73 views

arcpy fails to get spatial reference in hydro script

I have an ArcPy script that extracts a stream network from any chunk of terrain. It takes the terrain and if it's in a GCS, it projects it to the correct UTM zone prior to further processing. Though ...
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1answer
143 views

Find minimum downstream flow distance from each polygon to any polygon in other feature class

The Problem: I have two polygons feature classes, let's call them "SourceAreas" and "DangerAreas". For each SourceArea, I need to know if water could flow to any DangerArea and if so, what is the ...
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0answers
39 views

SAGA Maximum Flow Length problems with the Coordinate systems

I'm new to SAGA. I've got a srtm data set from europe and want to charge the maximum flow length especially from the river Elbe. The data is in WGS84 So first I ran the tool "Fill Sinks"(Wang & ...
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0answers
652 views

Preparing SRTM (hgt) for use in SAGA GIS?

I am trying to prepare a raster file which i could use with SAGA processing tools for hydrologic analysis in QGIS. I am using Win 7, 32 bit, QGIS 2.14.20 and SAGA 2.3.2 I downloaded the srtm file in ...
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1answer
320 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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1answer
64 views

How much precipitation must fall within a catchment area to fill up a sink’s entire volume assuming that the runoff conditions are perfect

I am performing an exercise and I need to answer these question, any hints would be extremely useful. How can it be calculated how much precipitation that must fall within a catchment area to fill up ...
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0answers
929 views

Watershed / drainage network analysis; floating point or integer raster for input?

I am a little desperate to find a solution to my problem. As I have detailed in this post I am unable to create a detailed drainage network (and catchments) from high resolution LiDAR data. I think ...
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2answers
69 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
50 views

How can I reduce the size of shapefile (.prj, .shx, .shp) up to 8 MB? [closed]

It is sub basin photo which I want to upload to CHRS so that I can to download satellite precipitation data (https://i.stack.imgur.com/EQt3v.jpg)
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1answer
342 views

Cumulative delay function for rainfall-runoff modeling using TOPMODEL [closed]

I am trying to model rainfall-runoff using TOPMODEL in R. The TOPMODEL needs an input called "cumulative delay function". The R documentation says "Flow is routed through a delay function which ...
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1answer
306 views

Creating slope map in ArcMap?

I want o create one slope map for my model but I have one big problem. I have contours lines and mass points and I create a DEM using topo to raster but if I want to create a slope map from that DEM I ...
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1answer
566 views

Fill DEM with water [closed]

I want view how a volume of water calculated with Hydrologic Study, accumulates in lower parts of my DEM at 1 meter resolution. My goal it's view the level that water reaches inside the raster. It's ...
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1answer
190 views

Support for hydraulic engineering projects in QGIS? [closed]

How is a DTM used in hydraulic engineering projects when working with QGIS?

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