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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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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 ...
Marco's user avatar
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5 votes
1 answer
524 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 ...
JWB's user avatar
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4 votes
0 answers
251 views

SAGA hydrological analysis in QGIS 2.8 on Mac

I am running QGIS 2.8 on a Mac machine and I want to calculate the catchment area using SAGA - Catchment Area. It starts running but after a while when QGIS wants to open the generated files there is ...
Thomas'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
3 votes
0 answers
393 views

QGIS Measure area below contour to develop elevation-area table

Is there a plug-in or methodology to measure areas under contours, which can be used to develop elevation-area tables? I know you can create contours as lines from DEMs, but you need to convert them ...
Extermiknit's user avatar
3 votes
0 answers
172 views

TauDEM: How to extract the longest flow path from an outlet to the basin divide as a shapefile

Using TauDEM I've created a number of derived raster products from an initial 30m SRTM DEM with a statewide (South Carolina) extent. Using the D8 modelling methods, I've created both the D8 Flow ...
elrobis's user avatar
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3 votes
0 answers
205 views

Extract representative slope profiles from hillslope polygons

With the help of the Whitebox Geospatial Analysis Tools I was able to easily extract hill slopes from a river network in combination with a flow direction map. Now I would like to extract ...
MonteCarlo's user avatar
3 votes
0 answers
157 views

Which geostatistical tools to use to determine surface changes over 40 years?

I have a data from the Weather station with SWEmax (snow water equivalent) collected over 40 years. I need to interpolate the data over my river's watershed and then, somehow, determine the ...
d1mOoOon's user avatar
2 votes
0 answers
167 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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2 votes
0 answers
84 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 ...
MHA99's user avatar
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2 votes
0 answers
127 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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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
  • 21
2 votes
1 answer
180 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 ...
Paulo Martinho's user avatar
2 votes
0 answers
75 views

Efficient random access into rasters for hydrological analysis

I'd like to implement an algorithm to extract Strahler Streams as geometric lines from a predefined stream raster. I've done this using GDAL by walking across the rasters from the outlets or at the ...
Rich's user avatar
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2 votes
0 answers
229 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 ...
A J's user avatar
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2 votes
0 answers
118 views

Short streams and tiny basins | QGIS-SAGA

After watching a lot of tutorials and trying all approaches I still somehow manage to get streams that are too short over my DEM, resulting in very small basins. I do it the standard way: Get a DEM ...
Sep's user avatar
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2 votes
0 answers
757 views

Vector map (rivers) to Raster. [ **ERROR 1: Wrong value for -outsize parameter.**]

I want to transform this vector map: To something like this I only tried to convert the vector map through Raster> Conversion> Rasterize But I get this Error: QGIS version: 3.6.3-Noosa QGIS code ...
Héctor's user avatar
  • 95
2 votes
0 answers
436 views

Extract longest flow path in ArcGIS pro

I did calculate Hydrology with Spatial Analysis tools==> Hydrology and now, I have streams and Watershed. In each watershed, I need to extract the longest Flow as a polyline for calculate slope. What ...
Jean's user avatar
  • 21
2 votes
0 answers
111 views

Channel network from high resolution DEM for flat areas

I'm working on channel network extraction from a LiDAR DEM (square grid max resolution 0,25 cm), and my area of study is vary flat with some part below the sea level. I applied the classical valley ...
Franco Perversi's user avatar
2 votes
0 answers
246 views

Choosing diffusion coefficient and other parameters for r.sim.water in GRASS7?

I'm trying to run r.sim.water in GRASS7 to simulate overland flow during a heavy rain event. My DEM has a resolution of 1m. I prepared it by adding values for buildings and included ditches and ...
a-ha's user avatar
  • 21
2 votes
1 answer
161 views

Connectivity of Streams

I have a line vector layer containing streams (see image below). What is the easiest approach to determine the connectivity of each stream segment (eg. sum of upstream nodes)?
kalakaru's user avatar
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1 vote
0 answers
29 views

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
1 vote
0 answers
39 views

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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1 vote
0 answers
41 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 ...
Bri's user avatar
  • 11
1 vote
2 answers
82 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
  • 41
1 vote
1 answer
124 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
0 answers
391 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
  • 89
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
  • 11
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
1 vote
0 answers
634 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 ...
BallpenMan's user avatar
  • 1,217
1 vote
0 answers
52 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 ...
SCH kiman's user avatar
1 vote
0 answers
73 views

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 ...
Tharindu Manamperi's user avatar
1 vote
1 answer
453 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:\...
Hansays's user avatar
  • 83
1 vote
0 answers
491 views

How to interpret the Maximum flow path length raster, from the SAGA Maximum flow path length tool

Does anyone know how to interpret the Maximum flow path length raster, after running the SAGA Maximum flow path length tool? I have used this tool and received a raster but I'm not sure how I can get ...
Ari's user avatar
  • 43
1 vote
0 answers
217 views

Get catchment area of a lake polygon in R

I have several DEMs as geotiff files which I load into R using raster::raster. Additionally, I have lake outlines (located within the DEMs) in the form of shapefiles which I load into R using raster::...
Abdirizak's user avatar
1 vote
0 answers
99 views

Why am I getting a straight flow path (stream) in obviously varying terrain -QGIS

Does anyone have suggestions on why the streams are sometimes represented as longer straight lines, even though the hillshade and contours generated from the same DTM (filled) clearly indicate that ...
BruceT's user avatar
  • 11
1 vote
0 answers
351 views

Urban runoff volume calculation

I was wondering if someone could help me out on how to calculate runoff volume within an urban area ? I have already produced different outputs: Filled DEM Catchment area Channel network flow ...
user avatar
1 vote
0 answers
92 views

Calculating the volume of multiple lakes with ArcGIS (3D Analyst)

I have the DEM of a glacier bed and want to calculate the volume of bed depressions that could form lakes. Data is available here: https://drive.google.com/open?id=1ERFdsqDGLH1a_FbxwawE_gPm0Au0Q9vT I'...
Florian Mlehliv's user avatar
1 vote
0 answers
492 views

Calculating drainage density

How can I calculate drainage density in QGIS if I have length for stream and grid line 1 km2? I need to calculate density per km2.
Miri55's user avatar
  • 11
1 vote
0 answers
902 views

SAGA: could not initialize data objects (QGIS 3.6, Mac 10.14)

I was trying to generate a catchment area from a DEM and got the error message: The following layers were not correctly generated.<ul><li>/var/folders/ft/rbsnpzy96r76t8rkj5fdtzc40000gn/T/...
Jesse Yishai's user avatar
1 vote
0 answers
18 views

Calculating SCS curve numbers using DSM instead of DTM

Are the curve numbers (calculated by SCS Curve number method) through DSM (Digital Surface Model) valid? Most of the SCS curve number studies focus on calculating curve numbers through a DTM (Digital ...
rhafeez's user avatar
  • 11
1 vote
0 answers
46 views

Split single polyline network at a point feature to make unique fields with unique distances

I am working with a large river network polyline shapefile. I am trying to calculate a dendritic connectivity index using a point shapefile representing locations. The river network shapefile has a ...
Fully Aquatic's user avatar
1 vote
0 answers
2k views

Displaying flow direction using arrow in ArcGIS Desktop?

I created a flow direction raster out of a DEM using ArcGIS Spatial Analyst Tools/ Hydrology, so the directions are coded in raster values as displayed below. [http://desktop.arcgis.com/de/arcmap/10....
Maja Ott's user avatar
  • 435
1 vote
0 answers
61 views

Automatically locating endpoints (river sources) in a stream network

I have a stream network in ArcGIS 10.2.2 and I would like to know if it is possible to automatically add endpoints based on the stream network. The network is pretty big and doing this manually ...
Gabriel Alcântara's user avatar
1 vote
0 answers
1k views

Qswat in newer version of QGIS

How can I setup QSWAT in newer versions of QGIS ? The link here says QSWAT requires QGIS 2.6. I tried installing QSWAT in new versions and it couldnot be done. Is there a way to install QSWAT in new ...
anup's user avatar
  • 333
1 vote
0 answers
236 views

Adding curb/gutter and subsurface storm drain networks to watershed analysis in QGIS

I need to do a neighborhood scale drainage analysis. The analysis needs to accurately show the drainage area to each storm drain inlet. Using GRASS on QGIS 2.12.1 on OS X, I have been able to ...
Chris M's user avatar
  • 11
1 vote
0 answers
182 views

calculate flow accumulation in a river with two outlet points

I'm trying to calculate flow accumulation layer (with arcGIS) in a basin with 2 outlet points. I have used "dem reconditioning" tool to modify my dem according to a vector layer, which contains my ...
Nick's user avatar
  • 19
1 vote
0 answers
103 views

Deriving Stream-Velocity out of a DEM

I'm using Arc GIS Toolbox Hydrology...everything works fine. Moreover, it is possible to derive the potential stream velocity just out of the DEM? Informations about rainfall, infiltration, hydraulic ...
JHB's user avatar
  • 11
1 vote
0 answers
161 views

Getting distance from nearest stream and elevation to nearest stream?

I need to know if there are simple commands for this 2 points: the distance from the nearest stream, D [m], defined as the length of the path that hydrologically connects the location under exam to ...
Luca Bucci's user avatar