Questions tagged [watershed]

Use this tag when asking a question about a watershed related to GIS environment.

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How can I delineate a watershed into subbasins of a certain size, say 2-4 square miles?

Using ArcMap or Arc GIS Pro. I heard there was a way to do it using ArcHydro tools, but I haven't been able to find that either.
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Delineating subcatchments for multiple storm drains

I have a shapefiles with over 3500 points that represent stormwater inlets within an urban watershed. I'm trying to determine the contributing catchment area for each inlet using a DTM in which I've ...
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Finding longest flow path in multiple basins at once

In my watershed I have around 400 basins. I need to find the max flow length in each basin. The "Flow Length" tool creates the flow length for the entire watershed, not for each individual ...
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Watershed tool in for loop on single feature point shapefiles creates empty rasters in ArcPy

I am using ArcMap 10.8. I have a flow direction raster and many point shapefiles with one feature each. I want to calculate one raster watershed for each point shapefile fd = "C:/sample/raster/...
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Seeking description of SAGA's Watershed Segmentation parameters

I'm trying to understand some of the parameters in the Watershed segmentation tool in SAGA. Join Segments based on Threshold Value - Available Choices: [0] do not join [1] seed to ...
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1 answer
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Hydrological catchment area for a road segment (QGIS)

I try to calculate the hydrological catchment areas for road segments in a mountainous region in QGIS. As far as I see, I can only calculate watersheds in general or for particular points. Is there a ...
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0 votes
1 answer
58 views

Basin code in Google Earth Engine

How to find 6digit in HYBAS_ID of "WWF HydroSHEDS Basins Level 7" database. Technical Documentation says that: Next 6 digits represent a unique identifier within the HydroSHEDS network; ...
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1 answer
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Problem with r.fill.dir on merged raster layer

I am going to use r.fill.dir on an area. The downloaded data comes as a set of tiles that puzzle together. In order to delineate watershed across tiles I need to merge them to a complete raster. ...
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37 views

Displaying in QGIS a TIFF product exported from GEE

I am new in GEE and am attempting to export and use a tiff product (WWF HydroSHEDS Basins Level 9) from GEE (output image, details, and code are shown below). The problem comes when importing and ...
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1 answer
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Distance to a polygon along the stream flow path

I'm using Arc Hydro Tool for watershed processing and management. I'm in a stage where I need to calculate the distance of all cells in a raster (the study area) to some polygons along the flow path. ...
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2 votes
1 answer
23 views

I want to use create legislative district polygons based on watersheds using QGIS, preferably

Generically, the problem is to take small polygons (HUC 12 watersheds intersected with counties and/or minor civil divisions) and disolve those into larger polygons that meet a couple of criteria: ...
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2 votes
1 answer
122 views

Using Watershed Basin from SAGA in QGIS

I have a weird phenomenon going on in QGIS. I want to derive a channel network and also the catchment areas using "watershed basin" from SAGA. In the end I want to have the flow direction ...
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Difference between catchments and watersheds in Arc Hydro

The catchments are made in the the terrain preprocessing, but the watersheds are made in watershed processing. Do they not give the same polygons? Does the watershed tool have more attributes?
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Water spread using SAR images (Sentinel-1) in Google earth Engine. Converting into Vector

I am running a water spread mask of Karnataka, India using SAR imagery (sentinel-1). I want the water classified pixels to be in vector (shapefile) to export them to google drive.. As I am new to ...
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1 vote
0 answers
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Selecting area upstream in watershed tool of ArcMap

How do I calculate the watershed at several locations using the watershed tool of ArcMap? When I am doing it, I get the watershed cut at all the points, and not all the watershed upstream. I set the ...
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1 answer
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How to isolate cooling influence of green roofs from land surface temperature data? [closed]

The idea in summary is to use land surface temperature (LST) data as a means to draw cooling extents around green roofs, as if you were drawing watershed basins around a lake, where high temperature ...
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51 views

What interior watershed basin means in GRASS GIS?

I am not sure of the definition of exterior and interior watershed basin. The definition given by the documentation is not very clear : Basin threshold The minimum size of drainage basins, defined by ...
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Manually create a DEM from survey data

I would like to create a DEM for a parking lot catchment, so that I can model surface water runoff paths in ArcGIS Pro. I have raw elevation survey data, collected at grid line intersections across ...
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1 vote
1 answer
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Flow Direction flowing opposite to actual direction

I am using ArcMap 10.7.1. I am trying to delineate multiple urban watersheds in GIS for the City of Denver (sometimes called sewersheds) using Spatial Analyst. I am looking at several drainage points ...
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3 votes
0 answers
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Breaking up existing watershed polygons by flow to individual tributaries

I have an existing hydroshed dataset (HydroBASIN lev12 basins from the HydroSHED dataset) that I would like to split up further, so that each tributary has its own basin delineated (see below). I ...
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Calculating the greatest length of a polygon using QGIS [duplicate]

I'm new to QGIS and I need to know the easiest way to calculate the greatest length of a polygon. I already know the "rule" tool but I want to do it automatically because I have a huge ...
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5 votes
1 answer
94 views

Selecting the transect lines which touches the divide of a polygon from the river line

I have a polygon and transect lines which passes inside the polygon. Here I want to select the lines which touch the drainage and divide. The transect lines split at the river intersection. Since ...
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2 votes
1 answer
66 views

Exporting same attribute values to separate layers and merging them in QGIS

I am trying to split watersheds of the same attribute table into separate layers. The Two two repeated values, for eg. SW1 and SW1 both are splits from a same watershed called 'SW1'. I am trying to ...
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0 answers
12 views

ArcGIS tool which shows all cells a point flows into?

Is there a tool that is effectively the inverse of flow accumulation of a pour point - as in, if I have a specific point that is the site of potential pollution, is there a tool which will show all ...
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4 votes
2 answers
362 views

Error while doing Watershed analysis using Python

I am trying to do watershed analysis using Python in jupyter notebook. Whenever I am passing commands regarding watershed delineation in Python I am getting output as raster matrix and when I am ...
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0 votes
0 answers
51 views

Finding a pour point in a polygon?

I have a polygon shapefile (created by someone else) that is a bunch of little watersheds. Unfortunately, it doesn't include any coordinates in the attribute table for the lat/long of the pour point ...
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1 answer
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Determining if species point data is upstream or downstream of artificial fish passes using ArcGIS Pro

I am working with ArcGIS Pro. I am working on a project to determine how to prioritize restoration of artificial fish passes. I have been supplied with species point data, point data of the artificial ...
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1 vote
1 answer
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GRASS GIS change raster output size?

I have a large inut raster geotiff map of size 12000x9000. I am running r.watershed to output a stream raster map. However it is much lower resolution, only about 960x711. How do I make GRASS GIS / r....
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1 vote
2 answers
479 views

Why no need for "fill-sinks" when using r.watershed in GRASS QGIS?

I've seen a few places that when using the r.watershed function in GRASS QGIS, you do not need to use the "fill-sinks" procedure on the DEM before running the function. According to the ...
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1 vote
0 answers
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TauDEM: Missing cell area contribution

I have a terrain, that looks like the below: The geotiff file can be found here I run the geotiff file with the taudem, with the threshold value =10 1. PitRemove.exe Site6.tif 2. D8FlowDir.exe -p ...
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1 vote
0 answers
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How to train or calibrate stream flow accumulation using observation data?

I need to calculate flowrate at designated coordinates (Point of interest - POI) in a watershed. I have real-world data from stream gauge stations along this watershed for each 50-150 km2 rainfall ...
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581 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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0 votes
1 answer
27 views

How can I export a Seed Points layer as a image?

I have the Seed Points layer produced by Watershed Segmentation. I want to export is as a image (with background). How can I do this? I understand that I can do Project->Export->Export Map to Image. ...
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1 vote
1 answer
57 views

Is it possible to create specific-sized watershed in a GIS environment? [closed]

I used the GRASS gis module to design catchment area with a minimum size of 2 kmsq. However, I would like to know if, in addition to the minimum size, I can limit a maximum size of 5 kmsq for them. In ...
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1 vote
2 answers
2k views

Why does running the SAGA Upslope Area tool in QGIS result in a 0 (zero) to 0 (zero) histogram and an all black layer?

I am using QGIS in order to delineate a watershed, and am using 1/3 arcsecond DEMs. I have created a Filled DEM using the SAGA Fill Sinks xxl (Wang & Liu) tool. Next I ran the SAGA Channels and ...
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1 vote
0 answers
51 views

Watershed Delineation for Specified Streams

I have a set of streams (currently a shapefile (line)) which I need to delineate the watersheds for. I have attempted to use various QGIS tools, however, each tool I have tried is for delineation of ...
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2 votes
1 answer
497 views

Individual tree segmentation using R-package lidR [closed]

I have some questions about individual tree segmentation in lidR. I'm looking at using the function lastrees with algorithm watershed. My first question is how to apply it for large areas. How big ...
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0 votes
0 answers
18 views

Scale national economic data down to a watershed

Economic Input Output databases such as e.g. the World Input-Output Database by the European Commission contain economic (and often environmental) statistics. The spatial resolution of data provided ...
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12 votes
0 answers
390 views

Accessing watershed boundary for lakes in R

I have had success accessing unique database IDs and polygons for various lakes in the US. I'm now looking to get polygons for the watersheds associated with these lakes, but have stumbled a bit. ...
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1 vote
1 answer
105 views

Delineating small scale / subwatersheds using ArcGIS Desktop

I have a number of data points showing the placement of stream gauges. What I'd like to do is to delineate the subwatershed for each point, so that when rainfall events occur, I can see the drainage ...
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1 vote
0 answers
115 views

Fixing Discontinuous Stream Networks using ArcMap

I am currently working on a project in ArcMap 10.6.1 involving urban sewershed delineation, however, I am stuck with a discontinuous stream network. I took a LiDAR DEM from NOAA and subjected it to ...
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2 votes
0 answers
19 views

Variations in the number of Sub-Watersheds delineated by various tools [closed]

I have demarcated sub-watersheds using different tools like ArcHydro, ArcSWAT, and Hydrology tool (ArcGIS). The same input data have been used in all tools. There are 35 watersheds derived using ...
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-1 votes
1 answer
42 views

basin layer from r.water.outlet Tool has values but is not rendering anything

I'm trying to deliniate a watershed with QGIS and used this tutorial to do so https://geogeek.xyz/catchment-delineation-with-qgis.html 1) r.fill.dir to create depressionless DGM 2) use r.watershed ...
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7 votes
1 answer
364 views

Rockfall analysis (Nearest neighbor downhill) in QGIS

I am working on a rockfall guide for QGIS and I'm currently stuck on one of the stages. I currently at a point in the guide where I have two point layers one "rockfall release point"-layer and "...
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1 vote
1 answer
37 views

Seeking quarternary watershed map of Eastern Ontario?

I am looking for a quarternary watershed map of Eastern Ontario. Where is the best place to look for this? I am currently using the ArcGIS Online basemap software to create my maps. I have a CSV ...
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3 votes
0 answers
63 views

What is the complexity (big / little o) of the ArcGIS watershed delineation algorithm? [closed]

I'm curious about the complexity, in terms of Big or little O notation, of watershed delineation algorithms that are implemented in ArcGIS. I imagine that these will be dependent on either the size ...
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0 votes
1 answer
312 views

Calculating distance between points following flow direction on ArcMap?

I delineated flow directions in a watershed on ArcMap (10m DEM). Then I want to calculate distance between two points 'following' the flow direction in each raster cell, not a straight line distance. ...
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1 vote
0 answers
41 views

What does the values of Watershed Accumulation, Basin, In QGIS indicates?

While performing watershed module in QGIS each output gives some value range while changing color palette. what does it actually means in accumulation , basin, stream flow. What does the value ...
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0 votes
0 answers
72 views

Watershed delineation by using QGIS with ifsar dtm 5m resolution of grid

I had some problems during running the channel and drainage basin with an IFSAR DTM, 5m resolution. I followed these steps, according to the guidance from website of QGIS: I reprojected the DTM to ...
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2 votes
1 answer
91 views

Using GageWatershed Function in TauDEM?

I have a D8 flow direction raster made from with TauDEM's D8FlowDir method and a point vector with an attribute 'id' for each. For some reason when I use these two as input in the GageWatershed ...
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