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Questions tagged [watershed]

Use this tag when asking a question about a watershed related to GIS environment.

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10
votes
4answers
4k views

What Algorithm is used by ArcGIS Watershed tool?

Does anyone know what type of algorithm is used in the ArcGIS Watershed tool (in the Spatial Analyst package)? Very little information given on Esri's website ... but I suspect it may be some kind of ...
8
votes
1answer
724 views

Basin creation GRASS vs. flow direction

I have a strange behaviour in QGIS with GRASS tools. I am trying to create basins in the alp region and use he SRTM3 data. As I can see on the flow direction raster the SRTM3 data seems to act nice: ...
8
votes
1answer
2k views

Watershed delineation taking into account lake/reservoir

My watershed has several big lakes. When I delineated my watershed, I had some unwanted subwatersheds and river segments inside the lakes (see fig. below). I want to tell ArcGIS/ArcHydro to delineate ...
8
votes
1answer
8k views

How to find the watershed area for each point in the river network using DEM?

Update#1: Thanks, Micha, I have followed your instruction and successfully use the modules in GRASS. I use r.watershed to get the basin raster and the drainage line: and I use r.water.outlet to get ...
7
votes
4answers
17k views

General steps to create watershed boundary in ArcGIS Spatial Analyst?

I am an ArcGIS beginner. I have a CD of GIS files of a city and intend to work on watershed management. There are different file names in different formats on CD. Like .shp, .shx, .dbf, .sbx. and ...
7
votes
1answer
2k views

When computing flow direction, the D8 algorithm is used - are there major differences if others are used?

I am a student working with Hydrological models. Within these models we can route water across a DEM (within a delineated watershed or just within an un-delineated DEM) using many different flow ...
7
votes
1answer
178 views

Rockfall analysis (Nearest neighbor downhill) in QGIS

I am working on a rockfall guide for QGIS and I'm currently stuck on one of the stages. I currently at a point in the guide where I have two point layers one "rockfall release point"-layer and "...
6
votes
2answers
1k views

How to find the watershed for each outlet point and sum values within it?

I have the following files to work with: Stream network of a basin; Outlet points for each segment* of the network and Points which represent water withdrawals along of the stream, which are not ...
5
votes
2answers
380 views

Numbering Watersheds using ArcGIS Desktop?

I am working with a watershed map, and I was wondering if there is a function or a way that I can get ArcMap to number the watersheds. For instance, if we have watershed X numbered as 0, I want the ...
5
votes
1answer
517 views

Does this ArcGIS flow accumulation example have an error?

The lower right corner of the flow accumulation example in ArcGIS Desktop's documentation has a flow accumulation value of 2. However, I only see one cell flowing into the lower right corner (the ...
5
votes
1answer
6k views

How to assign correct flow direction to stream network polylines?

I would like to create a map showing the results of watershed analysis as well as the resulting stream network with flow direction. I have a stream network which has been created from the flow ...
5
votes
1answer
685 views

What are definitions of watershed segmentation, local maxima, variable window search, regarding LiDAR for vegetation?

I am not familiar about Lidar. I want to measure trees height and number of trees. I guess, watershed = to locate the trees, local maxima = to measure trees height. I used these methods in SAGA GIS. ...
5
votes
2answers
157 views

Does the common flow accumulation techniques still work over flat area?

My terrain is a highly developed area--which means that It involves lots of flat area ( gradient=0) because they have been properly paved. And it involves sudden drop, such as retaining wall, or ...
4
votes
2answers
124 views

Getting 8 digit watersheds for USA

Is there an alternative source for 8-digit (vector shapefiles) US watersheds? The USDA link is down and they are not responsive to my query for getting the data: https://gdg.sc.egov.usda.gov/
4
votes
1answer
6k views

Water Flow Analysis in ArcGIS Desktop?

If I know that 10,000+ gallons of water were going to be dropped at a single point how could I model where it would flow. I would prefer something that worked in ArcGIS and could create a layer.
4
votes
2answers
545 views

Is D8 flow accumulation algorithm still suitable for watershed computation if terrain contains lots of flat area?

My question is inspired ( and similar) with my previous question. But this question is more concerned about the suitability of D8 ( or in general non-dispersive) flow accumulation algorithm for ...
4
votes
2answers
8k views

How to delineate watersheds in QGIS?

I am using qgis 2.14.17 with ubuntu16. Having as input data a DEM of the region and a river network. In the manual of qgis they suggest to use a toll of qgis: Catchment area (Parallel); I dont have ...
4
votes
1answer
1k views

Get drainage basin of a polygon (with QGIS, GRASS or other FOSS)

Using a polygon shapefile and a raster DEM, I'd like to find a way to get the drainage basin of a polygon area — that is, the area of all cells which drain into or through the cells contained in the ...
4
votes
1answer
149 views

Watershed Tool Straight Edge Problem

I'm trying to accurately delineate a watershed into sub-basins using dams as pour points. I'm using the hydrology toolset, but I can't seem to get rid of straight edges that are along some of the ...
4
votes
2answers
501 views

Delineating catchments upstream of flow sites [duplicate]

I have many flow sites and I used them to delineate catchments upstream of each flow site using Spatial Analyst Tools > Hydrology > Watershed. As you know using this tool, you'll get the catchments ...
4
votes
3answers
5k views

How to find out the Basin Length?

I am doing Project on Drainage basin, to find out the Elongation ratio I need to find out Basin length, Can any one of you tell me how to find out BASIN LENGTH using ArcGIS or any other way. My data ...
4
votes
1answer
963 views

Watershed extraction using different DEM tiles

I would like to extract the watersheds for a particular area using QGIS. However, I only have Aster 30m DEMs to work with, each tile covering one degree square. The problem is that I need to use ...
4
votes
1answer
362 views

How to calculate distance of gauging station to outlet point in watershed?

I have a gauging station point with elevation. Also have a watershed generated for the same area. I just want to know how to calculate the distance along the flowpath from the station to the outlet(...
4
votes
1answer
557 views

Does r.stream.basin still exist? GRASS-QGIS2.18.7

So I'm following steps in another topic that seems to date to January of this year and is exactly what I want to do, here's the link: Get drainage basin of a polygon and at one of the last steps in ...
4
votes
1answer
351 views

Could bridges prevent ArcMap from creating correct watersheds?

I have a very detailed DEM of a region in Northern Germany. For hours I tried creating correct watersheds but my results all look illogical. Is it possible that bridges disturb the ArcMap Tools? I ...
4
votes
0answers
170 views

Watershed delineation with meandering river?

I'm using ArcGIS (Hydrology toolbox) for watershed delineation for a number of pour points, and I'm running into problems with very meandering rivers on extremely flat alluvial land (Amazon basin). ...
4
votes
0answers
342 views

Different watersheds for same area because of “burned streams”

Im trying to analyse where water is flowing which rains down to my project area. This is the DEM I have (my project area is bordered blue, the red marks are my pour points): I learned from another ...
4
votes
0answers
689 views

Error when using r.watershed in QGIS 2.10.1 with Grass

I am running r.watershed within QGIS processing the I get the error below. I draw your attention to: GRASS_INFO_WARNING(2205,1): Subprocess failed with exit code 256 GRASS_INFO_END(2205,1) Does ...
4
votes
0answers
2k views

GRASS GIS - r.water.outlet - What is my mistake?

I'm new to GIS - more so in GRASS GIS. I installed GRASS GIS 6.4.3svn in my Windows 7 machine. No problem in installation. Downloaded SRTM-Geotiff file Location, Mapset all o.k Used r.in.gdal to ...
3
votes
2answers
16k views

Calculate line distances inside of polygons using ArcGIS for Desktop?

I'm working with two data sets: NHD polyline stream layer for my entire state HUC Watershed boundary Polygons for the entire state I am looking for a way to calculate the total length of streams ...
3
votes
2answers
4k views

Python code to compare two fields in different feature layers?

I have two shapefiles which encompass 3897 features each. Corresponding shapefiles (village and watershed that flows into it) have the same ID (ws_id in one, OBJECTID in the other). Many watersheds ...
3
votes
4answers
18k views

How to calculate for every basin/sub-basin, drainage area at every elevation contour along stream?

With DEM as a source, I created all necessary files like flow direction, accumulation, slope, streams, watersheds, pour point etc... In my watershed (basin), I have many sub-watersheds (sub-basin) ...
3
votes
1answer
747 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 ...
3
votes
1answer
1k views

Selecting point to obtain water basin leading to it

For the past few days, I have been working on building a watershed model including drainage basins and find that I am not looking for a global watershed and basin distribution, I am looking to ...
3
votes
1answer
108 views

Drainage basins ignoring lake

This is my first time writing in this forum and I hope this question offers some quality of information easing a solution. Here goes. I am new in analyzing hydrology with DEMs and I have followed ...
3
votes
1answer
690 views

Can't get GRASS r.water.outlet to work

I'm new to GRASS. We want to delineate a watershed using the LIDAR data we have our hands on. I tried to follow several procedures to do so, but despite all my efforts, I can only get it to select a ...
3
votes
2answers
2k views

Understanding flow accumulation

I used this youtube video: https://www.youtube.com/watch?v=FSblORbDyhc&list=PLWJ2X2wvq78QRGzl8Un5ADF0_4m5t99iD&index=11 to learn how to run flow accumulation and was successful. I realize it ...
3
votes
2answers
2k views

ArcPy script stops running randomly with no error returned

I am doing a batch watershed and analysis process on 135 points. This script worked great the first time I ran it. Ever since the first time, however, I have had the script stop at random moments. ...
3
votes
1answer
234 views

Watershed-segmentation with orfeo toolbox

I work at the moment with the watershed-segmentation from the orfeo-toolbox. After the segmentation the pictures is split into squares. Specially the square in the middle seems to be deeper the the ...
3
votes
1answer
892 views

How to interpolate raster data using computer vision (OpenCV)?

Background A raster file collected via LIDAR records the topography of a watershed. To properly model the watershed, the river must appear continuous without any breaks or interruptions. The roads in ...
3
votes
1answer
1k views

Flow direction and catchment area polygons for utility water pipes

I'm working on a project where I need to show which direction the water would flow from a water pipe in case there is a pipe burst. I also need to show catchment polygons(area affected). This was ...
3
votes
1answer
346 views

How to determine which stream end point is at the basin outlet?

I am working with streams, stream end points, elevation raster and I have created basins using the watershed tool in ArcGIS. From that data, I would like to determine for each basin, which single ...
3
votes
1answer
68 views

Watershed a catalog RasterStack in place of RasterLayer in lidR?

I want to use watershed with lidR package on a catalog. I paste this command: rep <- "/home/lasfiles" new_ctg <- catalog(rep) lidR:::catalog_laxindex(new_ctg) opt_output_files(new_ctg) <- ...
3
votes
1answer
97 views

Tolerance setting in watershed segmentation(EBimage/lidR) in R

Can anyone here explain to me what the "tol" parameter in the watershed algorithm implemented in the BioConductor package EBImage (and lidR) does? I find the explanation in the EBImage help difficult ...
3
votes
1answer
536 views

How to separate shared watersheds?

I put a pourpoint at the end of a headwater stream, then another further downstream that is fed by that headwater stream plus two others. Obviously the pourpoint further downstream is going to share ...
3
votes
0answers
33 views

What is the complexity (big / little o) of the ArcGIS watershed delineation algorithm? [closed]

I'm curious about the complexity, in terms of Big or little O notation, of watershed delineation algorithms: More specifically, does the time required to perform a watershed delineation depend on the ...
3
votes
0answers
347 views

ArcHydro catchment area of specific stream segment

I am given the task to create the catchment areas of specific streams/lakes. To sum it all up, I am looking to find the catchment areas for lake 1, stream, lake 2 and downstream of lake 2 all ...
3
votes
0answers
964 views

Using WATERSHED to delineate tree crowns in ArcGIS Desktop? [closed]

I'm trying to delineate and count trees from a DSM/DTM generated from a UAV survey. It's from a citrus grove where trees are growing in different spacing. I have developed a workflow that works for ...
3
votes
0answers
235 views

Preventing flow accumulation in one watershed from traveling up tributaries into adjacent watersheds?

I am using TauDEM in ArcMap 10.3.1 to try and calculate flow accumulation and generate stream networks for HUC10 watersheds. I am using 3m DEMs acquired from the National Map. The HUC10 I am working ...
3
votes
0answers
616 views

Watershed delineation?

I'd like to delineate the catchments upstream of the sampling points. In order to do that, I have done the following: Burn the rivers into the DEM using ArcHydro>DEM Manipulation>DEM reconditioning; ...