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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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Drainage area at a point of my choice

I want to get drainage areas at specific points (the points are places I want to put culverts for a railwork construction). The thing is that when I run either upslope area or PCraster tools, the ...
dimitris fotopoulos's user avatar
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18 views

QGIS SAGA Isochrone crashes

I am trying to make isochrones with SAGA GIS. I am now having a problem that: The Isochrone variable speed crashes or give odd outputs. I have a DEM with 3.6km2, but the output is about 3 pixels, even ...
ununanswered's user avatar
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How to find a specific distance upstream from a point

I am trying to find a simple way to map sections of a river which are covered by a Mink trap. So I have a river layer and a points layer for where the traps are placed. I want to select all rivers (...
Owain's user avatar
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2 votes
1 answer
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Transfering attribute from line layer to polygon layer by their overlay in QGIS

I have a polygon layer that represents sub-catchments and a line layer that represents a stream network. There is exactly one feature in the line layer for each polygon. I have used v.rast.stats to ...
Fabi's user avatar
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QGIS: Further subdivide sub-catchments based on DEM

I have a DEM and a vector layer with existing hydrological sub-catchments. Is there a way in QGIS to further subdivide the sub-catchments based on the DEM?
Fabi's user avatar
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Perform a Mann-Kendall test on grd dataset downloaded from imd portal

I have a grd file downloaded from imd portal, now I want to perform a mann kendall test on this grd dataset. But I am not getting how to read grd file in Python and how to perform Mann-Kendall test, ...
Kadali Lakshmi Nirmala's user avatar
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164 views

QGIS: Flow Accumulation Tool not progressing past 100%

I'm trying to do run the flow accumulation tool on a map where I am trying to extract drainage from a DEM however it has been stuck at 100% for several hours. I have put details of the files I am ...
Kcoj's user avatar
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2 votes
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165 views

ERROR 010658: Failure in distributed raster analytics operation. Error when using hydrology tool 'Fill'

I'm currently doing a watershed delineation and river morphology computation using ArcGIS Pro. I have the DEM of the area and started with the hydrology tool "Fill" but it keeps having an ...
zxz_341's user avatar
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1 answer
64 views

Strahler ordering of existing vector stream network data with a DEM (SRTM)

I have a vector stream network (CanVec) and an SRTM DEM. How can I elucidate the Strahler order and attach that value to the vector stream network? For some reason the CanVec data doesn't have ...
MJM's user avatar
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2 votes
2 answers
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Creating point at downstream end of polygon using ArcGIS Pro

I'm trying to automate the process of adding a point to the downstream end of each polygon in a layer in ArcGIS Pro (Running V3.2.0 on Windows 11). I have a layer with the stream network along with a ...
GOG's user avatar
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1 vote
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Creating Streams from endpoints and NHD Stream Layer using ArcGIS Pro with Spatial Analyst

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 ...
Bri's user avatar
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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 ...
Felix Chan's user avatar
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34 views

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 ...
mira's user avatar
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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 ...
Todd's user avatar
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110 views

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 ...
cheesetrap's user avatar
1 vote
2 answers
81 views

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 ...
scoite's user avatar
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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 ...
same11's user avatar
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1 answer
143 views

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 ...
OwnTheBanks's user avatar
1 vote
2 answers
271 views

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")....
dimfalk's user avatar
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2 votes
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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 ...
MHA99's user avatar
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1 answer
323 views

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), ...
ffinnm's user avatar
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1 answer
51 views

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 ...
tunar's user avatar
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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 ...
Link_tester's user avatar
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1 answer
42 views

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 ...
kaj.n's user avatar
  • 79
1 vote
1 answer
123 views

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 ........
Joey Woody's user avatar
1 vote
1 answer
175 views

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 ...
gis1234's user avatar
  • 319
2 votes
0 answers
125 views

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 ...
CrossLord's user avatar
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1 vote
0 answers
388 views

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 ...
jonsken's user avatar
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2 votes
2 answers
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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 ...
Matt Canada's user avatar
-1 votes
1 answer
37 views

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 ...
Andrea's user avatar
  • 29
-1 votes
1 answer
924 views

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?
tunar's user avatar
  • 141
1 vote
1 answer
814 views

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 ...
AM38's user avatar
  • 23
3 votes
1 answer
177 views

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 ...
Abdullah Nagy's user avatar
0 votes
1 answer
527 views

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 ...
EKOAndrew's user avatar
1 vote
1 answer
189 views

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 ...
AM38's user avatar
  • 23
0 votes
1 answer
375 views

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 ...
ZKB's user avatar
  • 1,154
0 votes
1 answer
68 views

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 ...
AKCamp's user avatar
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3 votes
0 answers
39 views

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 ...
user15564926's user avatar
1 vote
0 answers
58 views

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 ...
HarshUp's user avatar
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5 votes
1 answer
656 views

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, ...
fredrik.sundberg's user avatar
0 votes
1 answer
240 views

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 ...
W. Strabo's user avatar
0 votes
1 answer
817 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; ...
user2955459's user avatar
0 votes
2 answers
317 views

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. ...
fredrik.sundberg's user avatar
5 votes
1 answer
2k views

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, ...
Melanie Baker's user avatar
2 votes
0 answers
98 views

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 ...
Sofia's user avatar
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3 votes
2 answers
342 views

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 ...
Melanie Baker's user avatar
0 votes
1 answer
708 views

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 ...
Orca's user avatar
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1 vote
0 answers
83 views

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 ...
Zaineb Ali's user avatar
1 vote
0 answers
181 views

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 ...
J. Anderson's user avatar
3 votes
2 answers
256 views

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 ...
Chelsea Lynn's user avatar

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