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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Create Streams from endpoints and NHD Stream Layer [closed]
I have a dataset for instream flow water rights that delineates the length of stream based on upstream and downstream endpoints and the miles of stream. I'm trying to create a GIS layer for this ...
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FlowAccumulation working when run as geoprocessing tool but not in ArcPy
I have a problem with this code:
#actual problem code
flow_dir_rast = flow_dir
in_weight_raster = mine_flac_weight
data_type = "FLOAT"
flow_direction_type = "d*"
# run the flow ...
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How can I use Whitebox hydrology tools with areas of internal drainage (ie. true sinks)?
I'm trying to use some Whitebox hydrology tools on a raster where I want to set inland points as areas of internal drainage and I don't understand how the fill tools treat NoData points when filling ...
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QGIS Catchment Creation from existing line shapefile (streams)
I understand the general process of creating a catchment.
Get DEM data Fill sinks
Build stream network
Create a line shapefile of the stream network
Choose outlet location and obtain coordinates
...
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QGIS Strahler Order Too Many Stream Channels
I have this DEM file and I'm trying to extract possible rivers/streams from it.
However , when I run Strahler Order as tutorials on youtube indicate, the output shows too much lines that aren't really ...
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Using ArcGIS Pro to calculate required height of debris dam structure in stream when expected volume to retain is known
I have the locations of potential debris dam structures to be placed in a stream and know the contributing watershed area and the estimated debris volume (in m3) that would flow down that watershed ...
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105
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Calculating flow path length in R
I am currently trying to calculate the flow path length in a DEM towards a streamnetwork. My desired outcome would be a raster with values of how long the flowpath to the nearest streamcell would be ...
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47
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SAGA/Cross Profiles not running correctly
I cannot get SAGA's Cross Profiles tool to run, it worked a few weeks ago when I discovered it. I've removed QGIS as well as the appdata/local and roaming directories and updated to LTR 3.28.7 ...
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Generate a very accurate mask showing where rivers and streams are using a DEM in QGIS
I would like to create a mask layer to show what the specific widths of a river or stream would be with certain variables. I'm using a high quality 1mx1m resolution DEM. I am able to do some things ...
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136
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Estimating flow direction using `terra::terrain()` without NA values at the border
Performing some rather simple watershed delination analysis I noticed {terra} offers a function to estimate at least the flow direction based on elevation input via terrain(x, v = "flowdir")....
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How to divide watersheds by iscochrones/travel times in QGIS?
I need to divide my watershed by isochrones of equal travel time to the output, dividing my watershed to inter-isochronal areas in order to use the time-area method to calculate runoff time series, in ...
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Tracing a specified distance along a network using ArcGIS Pro
Using ArcGIS Pro 3.1.
I have some starting points snapped to a network of river lines (purple in image). I would like to trace exactly 500m away from these points in either direction as below (red), ...
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Validating that the smallest channel extracted using ArcMap (Hydrology toolbox) from DEM is the first-order stream
In ArcMap, the 'Hydrology' tool under the toolbox 'Spatial Analyst' can be used to extract the stream network, as described in detail here: extract streams from DEM. One step consists of using a ...
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How to extract channel network from DEM file in QGIS and avoid mixing stream from road [duplicate]
I am a bit new to QGIS world and want to extract catchment area and channels from a high resolution DEM file. I tried Strahler Order method available in my QGIS 3.22.9 but the results are not ...
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Calculate places with flood risk during rain
I want to evaluate a DEM to find out what places are likely to have standing water during heavy rainfall, based on topography and calculated water flows (see attached image). I have a sense I could ...
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How to add a column in one shapefile that is the sum of values in another shapefile?
I am trying to calculate a weighted average CN value for 500 drainage area catchments (S1-S500).
I have one file named "DA" which has S1-S500.
Name Total_Area
S1 1.5
S2 0.8
........
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141
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Finding average depth of filled sink using ArcGIS Pro
How to find out the depth of a filled cells (filled using "Fill" tool for a DEM)?
I have a DEM (50m resolution) for which I used "Fill" tool of the hydrology tool of ArcGIS Pro to ...
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Calculating upstream (contributing) area for >10,000 points using Python
I would like to create polygons of the contributing area for > 10,000 points.
I have all information that I need for this, including a 30m DEM, a river network (LineString geodataframe file) and ...
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264
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Python library for hydrology calculations for multiple points
I have a DEM (TIFF) with multiple points, which mark wells (right term?) of an underground pipe network:
I was wondering if there is a Python library which uses the elevation of the DEM to generate a ...
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1k
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Terrain creation error using a GeoTIFF file with HEC-RAS 6.2 - "object reference not set to instance of object"
I am attempting to import a TIFF file created in QGIS, into HEC-RAS. I have a projection file as the SRS definition for HEC-RAS, which is derived from a shapefile that lines up with the spatial extent ...
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Calculating locations that could be reached by gravity aqueduct (below certain slope from sources) using ArcMap
I am interested in finding the extent of areas that could potentially be reached by a gravity fed irrigation aqueduct from a river. I have a raster of potential sources, and a DEM. I know that for ...
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Is there any way that can help determine the flow direction of a river in a satellite image (Landsat)?
For example, there is a stream in the following image, but I find it difficult to determine the flow direction of the stream. Should it be from south to north, or the opposite?
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How to measure length of Sub-watersheds / Sub-Basins in ArcGIS Pro?
I am looking for guidance about reliable method of sub-basin length calculation.
I am a student and working on morphometric analysis for prioritization of sub-watersheds of a river basin. I am using ...
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147
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Drainage divide
I have drainage basins shapefile, some basins pour water to the east in the Sea and others to the west in the river.
I would like to create the drainage divide line that divides those pouring to the ...
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1
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358
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QGIS: Identify depressions/bluespots in the landscape [closed]
I'm looking for a way to identify depressions/bluespots in the landscape. I've tried using the SAGA tool "Fill sinks (Wang & Liu)" but for some reason all of the SAGA tools are greyed ...
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How to resolve the problem of multiple parallel streams and unmatched river flow in Stream Network?
I am working on sub-watersheds delineation of an area. The extracted streams do not match with the real world scenario. I have two issues;
there are multiple streams lines which do not match with ...
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244
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Determining maximum capacity of river using HEC-RAS
Is there a practical way to determine the maximum hydraulic capacity of a river in HEC-RAS?
I would like to know for each cross section of my 1D model what the maximum flow rate will be before ...
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53
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Tool generating hill slope forms (divergent, convergent, uniform) in QGIS
Does anyone know a tool or procedure for generating a raster file of slope forms (divergent = upper slope wider than lower slope, convergent = upper slope narrower than lower slope and uniform = upper ...
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LiDAR derived streams - map scale
Historically, streams were defined by the map scale. For example, for a map with a scale of 1:24,000 would mean that the streams identified on that map would be 1:24,000 streams.
With streams that are ...
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HEC-GeoHMS Outlet Point Connectivity
The "Check Data" option in HMS tab of HEC-GeoHMS is showing a problem in the VIP relevance points which is as follows:
Checking project points [VIP points]... Checking VIP Point: Outlet1
...
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501
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Delineating multiple nested catchments in R whitebox; prevent primary catchment from being cut by subcatchment
I am using whitebox tools in R to delineate catchments. I have 150 lakes in a rather small area so many of the lakes are within the same catchment.
I use
wbt_watershed(d8_pntr = ptr,
...
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189
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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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633
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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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222
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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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Calculating width of unusually shaped polygon in QGIS
I have a large unusually shaped polygon of surface water within 15km radius of a site. I would like to calculate the widths of all the polygons. I would be open to calculating it at regular intervals, ...
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86
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Bringing river bed to the same height as surrounding ground in QGIS
I have a DEM containing the current flow networks in an area. I also have a shapefile showing the same flow network. I would like to derive a new river network to see how water would flow if the ...
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291
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Calculating distance along line to central point QGIS
I have a layer of various water courses. I have a central location which is a reintroduction site for an animal. I want to calculate the minimum distances along the lines of the water course to the ...
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515
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QGIS Watershed Delineation - generated channels and drainage basins are incorrect
I am trying to delineate some watersheds using the SAGA GIS Tools in QGIS. The DEM I am using is the SRTM DEM. When I try to generate the channels and drainage basins using the SAGA>Terrain ...
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Delineate watershed
I have a problem with QSWAT. It does not take the delimitation of my catchment, I did all the solutions that I know.
I downloaded a new SRTM and the same projection with all the parameters. I ...
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QGIS: Creating a point at a set distance up/downstream from another point (dams or obstructions) on a line object (river)
I have a data set where I have shapefiles for the watercourses in a drainage basin (line/linestring) and locations of dams and other obstructions along them (points). I would like to create a new ...
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Counting upstream features based on flow direction line segments?
I am trying to find a way of counting how many lakes are upstream for each lake in my watershed. I feel as though I have the layers to accomplish this but am unsure of the tools/workflow. I have ...
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Merging river network features which should belong to same tributary of certain stream order in ArcMap without using Dissolve tool
I processed the DEM data through Arc Hydro to get the vector data of the river network. I recently tried to calculate the Horton-Strahler ratios and suitable flow accumulation threshold of it, yet ...
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Outputs of "Strahler Order" and "Channel Network and Drainage Basins" different despite same threshold
I ran the Strahler Order and the Channel Network and Drainage Basins tools both with threshold at 8 and using the same filled DEM. The results differ as shown below.
Strahler Order raster (only ...
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Dissemination on a network
I'm looking to map the streams in which certain pollutants are found. These readings are points, and we assume that the water downstream of each point is contaminated. The mapping is not binary but ...
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Identifiying the levels for streams derived from DEM
I am using GRASS GIS and I have been able to identify the various water-flow channels / streams using the documentation from r.watershed.
Now I wish to identify the levels of the streams. For example, ...
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85
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Exporting very large map to image in QGIS [duplicate]
I'm trying to use QGIS 3.10.14 to create a hydrological map to edit (as a PNG) in image editing software. My purpose is recreational.
I've paired the Copernicus EU-hydro river network with ESRI ...
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Does most topographic data come with Z Coordinates, and if so how do you put them in a QGIS map?
I am trying to create a map of the rivers in a large catchment. When I try to 'fill the sink', mine makes it as if the surface is flat. My rivers are just squiggly lines.
It doesn’t look like it has ...
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Issue with delineation using dem because of a DAM
I have a high-resolution DEM which I use it delineate watershed.
I am getting the delineation like this
The main branch is not getting delineating till the source.
So I used a hillshade to check the ...
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68
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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 ...
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How do you create upstream buffers at a specific distance from another polygon?
ArcGIS Pro / ArcMap
Licenses: Spatial Analyst, 3D Analyst
I'm working on a project in the Daniel Boone National Forest to create critical habitat areas in order to keep roadside pesticide applicators ...
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