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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3 votes
0 answers
522 views

Proper use of Modulus "%" operator in ArcMap [closed]

Objective: Gather pour points to define a specific-sized watershed. In this case, 1000 pixels. (for this thought exercise, watershed is to mean any point that flows through a pour point, regardless of ...
1 vote
1 answer
184 views

Error while running SAGA algorithms in QGIS 3.10.14-A Coruña

I've been trying to run several hydrological algorithms (Strahler, Fill Sinks etc) from SAGA in QGIS ltr and I keep running into the same error: The following layers were not correctly generated.C:\...
0 votes
0 answers
15 views

Change channelnetwork for watershed basins

Currently working with QGIS 3.16 and the SAGA toolbox. I want to change the flowlines from the channelnetwork (created from channelnetwork saga tool) to fit to the lokals drainage network. Is it ...
1 vote
0 answers
43 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 ...
1 vote
1 answer
58 views

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 ...
-1 votes
1 answer
30 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 ...
-1 votes
1 answer
37 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?
0 votes
1 answer
192 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 ...
0 votes
0 answers
155 views

"Channel Network & Drainage Basins" works if the filled DEM is from "r.fill.dir" and not "Fill Sinks (Wang & Liu)"

I'm using QGIS Desktop 3.16.9 and was doing this video https://youtu.be/2Ub0c7Ss-T4. The instructors used "Fill Sinks" and then the "Channel Network & Drainage Basins". When I ...
1 vote
1 answer
2k views

Getting upstream drainage area and what is difference between drainage area and basin area? [closed]

I have a Aster DEM, and from that I get the drainage network, and now I need to calculate the drainage area, but I don't know if the drainage area is equal to the basin area.
1 vote
1 answer
47 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 ...
0 votes
1 answer
70 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. ...
5 votes
1 answer
130 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 ...
4 votes
1 answer
951 views

Creating water surface from vector line in QGIS

I want to create a raster surface representing the flood level in a creek based on output from a 1D hydraulic model. I receive a 3D profile of the water surface in a creek line as a 3D Polyline (...
3 votes
1 answer
95 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 ...
0 votes
1 answer
45 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 ...
3 votes
1 answer
350 views

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 ...
1 vote
1 answer
94 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 ...
4 votes
1 answer
232 views

Limiting flow direction to D4 instead of using D8 in ArcMap?

Is there a way that I can limit flow direction to D4 instead of having it use D8? Preferably looking for a way to do it within ArcMap.
0 votes
1 answer
86 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 ...
0 votes
1 answer
25 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 ...
0 votes
1 answer
29 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 ...
1 vote
1 answer
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 ...
5 votes
1 answer
265 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 ...
3 votes
0 answers
32 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 ...
3 votes
2 answers
4k views

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

Data: DEM, 1/9th arc second (~10-meter), 239,891,470 cells, projected; Streams, National Hydrology Data set, high resolutions, 9,470 features vector; Streams, Same as above, but converted to a raster ...
1 vote
0 answers
12 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 ...
2 votes
2 answers
447 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 ...
1 vote
1 answer
3k views

Calculating longest flow path and avg. slopes for catchments with QGIS

I am a hydrologist and there are 2 important pieces of information I need for modeling. I need to know the longest flow path for each sub catchment in my area of interest and I need to know the ...
-5 votes
1 answer
205 views

Support for hydraulic engineering projects in QGIS? [closed]

How is a DTM used in hydraulic engineering projects when working with QGIS?
5 votes
1 answer
132 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, ...
2 votes
0 answers
64 views

Representing Hydrographic survey in QGIS

I have a depth Layer (soundings) and I would like to represent the labels the same way as in a Hydrographic Map. As you can see in the image bellow, we have this kind of representation in a ...
0 votes
1 answer
140 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; ...
5 votes
1 answer
305 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, ...
2 votes
0 answers
179 views

NA values as result from Grass functions (r.slope.aspect, r.sim.water) in R

As the result from r.slope.aspect I get a raster with only NA values. r.param.scale works, but doesnt generate dx and dy maps, which I both need for r.sim.water function. Code snippet 1 (initialize ...
2 votes
0 answers
35 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 ...
0 votes
1 answer
114 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 ...
2 votes
2 answers
79 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 ...
5 votes
3 answers
2k views

Generate Height Above the Nearest Drainage (HAND) using QGIS

I have a DEM I want to generate a HAND for and want to do so in QGIS. Does anyone know of any plugins or the processing steps to be able to do this?
5 votes
3 answers
400 views

Hydrological Enforcement of culverts in QGIS

I work on a farm and we are in the process of developing a surface drainage program for individual fields. I am using QGIS 3.16 and the publicly available 2020 QL2 LIDAR flyover of Indiana, and my ...
1 vote
0 answers
40 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 ...
0 votes
0 answers
9 views

Watershed analysis in ArcMap, interpreting results to find contaminant

I am doing an analysis to find a possible contaminant in a river. I have trouble interpreting the results of my watersheds. I have filled sinks, got a flow direction and flow accumulation and I have ...
1 vote
0 answers
75 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 ...
2 votes
1 answer
66 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 ...
0 votes
0 answers
36 views

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 ...
1 vote
0 answers
114 views

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 ...
1 vote
0 answers
47 views

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 ...
10 votes
5 answers
10k views

Tutorial on how to model flooding using data from gauging stations along rivers in QGIS?

Can someone please direct me to a tutorial where I can learn more about how to model flooding using data from gauging stations along rivers using QGIS?
0 votes
1 answer
17 views

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, ...
0 votes
0 answers
82 views

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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