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.
353
questions
1
vote
0
answers
35
views
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 ...
- 65k
0
votes
0
answers
61
views
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 ...
- 65k
0
votes
1
answer
182
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), ...
CommunityBot
- 1
0
votes
1
answer
281
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 ...
CommunityBot
- 1
0
votes
1
answer
225
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.
...
CommunityBot
- 1
0
votes
0
answers
19
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 ...
- 1
6
votes
1
answer
151
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 ...
CommunityBot
- 1
0
votes
0
answers
27
views
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
...
- 45
0
votes
0
answers
49
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 ...
0
votes
1
answer
249
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 ...
CommunityBot
- 1
5
votes
1
answer
465
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 ...
CommunityBot
- 1
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 ...
CommunityBot
- 1
1
vote
1
answer
374
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:\...
CommunityBot
- 1
2
votes
2
answers
1k
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 ...
- 147
1
vote
2
answers
54
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 ...
- 22.6k
0
votes
1
answer
109
views
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 ...
- 111
0
votes
0
answers
48
views
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 ...
- 53
3
votes
2
answers
1k
views
Delineating large scale watershed?
I would like to do some watershed delineation at national/regional level (using SRTM-90 data).
I have experimented with r.watershed (GRASS 6.4.3) but it fell over when I tried to do big stuff.
I ...
- 96
0
votes
1
answer
78
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 ...
- 9,414
0
votes
2
answers
138
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")....
- 937
2
votes
0
answers
64
views
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 ...
- 21
0
votes
1
answer
49
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 ...
- 65k
35
votes
2
answers
18k
views
LAS to DEM conversion [closed]
I regularly come across LiDAR (.LAS) files with elevation data. When I do, I always struggle to find a way of converting them to a DEM for hydrological analysis. I have developed several workflows, ...
- 65k
8
votes
1
answer
2k
views
Choosing parameters for SAGA Wetness Index?
I've been working with SAGA GIS to calculate the Topographic Wetness Index of an alpine catchment. I am using the tool Terrain analysis > Hydrology > SAGA Wetness Index because, compared to ...
- 1,094
5
votes
2
answers
4k
views
Calculating flowpaths downstream of a point
I am assessing the flood risk posed by pipeline failure. I need to calculate the likely flow-paths for flood water downstream of critical locations along the pipeline using GIS.
I'm familiar with ...
3
votes
3
answers
404
views
Hydrology, operational rainfall-runoff models
I am trying to collect information about operational rainfall-runoff models used around the world. I hope to build database with country outline with attached information what organization is covering ...
- 65k
2
votes
2
answers
2k
views
How to speed up batch watershed delineation?
I have a large number of pour points - approximately 250,000 for which I want to delineate the upstream watershed area using ArcHydro's "Batch Watershed Delineation". Given that it takes roughly 4-5 ...
0
votes
0
answers
38
views
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 ...
- 101
3
votes
2
answers
292
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 ...
- 11
1
vote
1
answer
274
views
Dissolving stream orders using Python rather than VB script
I've been trying to dissolve streams, using orders programmatically and I came across this VB script. The reason is that if I use ArcGIS dissolve, it merges the confluence of the same orders.
How do I ...
- 65k
0
votes
1
answer
39
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 ...
- 9,414
1
vote
1
answer
99
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
........
- 14.8k
1
vote
1
answer
141
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 ...
- 65k
2
votes
0
answers
100
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 ...
- 65k
7
votes
3
answers
4k
views
Tracing up stream network & tabulating attributes of polygons it passes through
I am using ArcMap and I am somewhat inexperienced when it comes to dealing with network analysis.
I have a stream network covering a very large area & some census data. My problem is: I want to ...
- 65k
3
votes
0
answers
539
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 ...
- 65k
1
vote
0
answers
267
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 ...
- 89
-1
votes
1
answer
33
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 ...
- 65k
-1
votes
1
answer
511
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?
- 6,486
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.
- 65k
1
vote
1
answer
556
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 ...
- 23
4
votes
1
answer
1k
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 (...
- 65k
3
votes
1
answer
148
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 ...
- 65k
0
votes
1
answer
361
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 ...
- 188
3
votes
1
answer
657
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
161
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 ...
- 23
4
votes
1
answer
283
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.
- 1
0
votes
1
answer
189
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 ...
CommunityBot
- 1
0
votes
1
answer
55
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 ...
- 15.5k
3
votes
0
answers
37
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 ...
- 68.9k