A watershed is the area of land where all of the water that is under it or drains off of it goes into the same place.

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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 ...
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3answers
593 views

General steps to create watershed boundary

I am a very beginner of ArcGIS. I got this 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, ...
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1answer
1k 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
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1answer
690 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 ...
5
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1answer
324 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 ...
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Water Flow Analysis

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. ...
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2answers
786 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 ...
4
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1answer
115 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 ...
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1answer
147 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 ...
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1answer
151 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. ...
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2answers
2k 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
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2answers
675 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
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1answer
160 views

Practical tools to delineate 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
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1answer
624 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 ...
3
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1answer
218 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
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2answers
256 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 ...
3
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1answer
2k 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 ...
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2answers
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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 ...
3
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1answer
89 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
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1answer
145 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. ...
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0answers
56 views

How to determine irrigable acres from a single source/point?

I am trying to graphically depict the exact amount of irrigable acres from a single point, in this case a headgate from a drainage ditch. Basically, I have the original water right decrees (i.e. ...
2
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2answers
2k views

Automatic Watershed Delineation

I am trying to delineate watersheds automatically using Arcgis/Achydro. I got the drainage area contribution of stream segment (part of stream) as shown in figure stream. The corresponding drainage ...
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1answer
143 views

Watershed Analysis

I am performing watershed analysis using Archydro tools in ArcGIS10. After calculating all flow direction, accumulation, drainage network when I perform watershed delineation, it gives me the same ...
2
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1answer
208 views

Storm Water flooding

Is there a method in Arc Gis for mapping storm water runoff in an urban environment assuming that the sewers are at full capacity. I just want to map roughly where the water will flow over the land ...
2
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1answer
239 views

Inland / crater watershed delination

Even though watershed delineation is a quite popular matter here, I have what seems to be a somewhat unusual demand. I start with a DEM which is constituted of a series of craters, all centered on ...
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2answers
270 views

How to do the loop when using GRASS module r.water.outlet?

I have seen this post:Watershed Analysis with GRASS, and I have a .txt file which contains coordinates of many points, and I want to use r.water.outlet to get basin area of each point. I type the ...
2
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1answer
486 views

Hydrology tool dataset in ArcGIS 10.1 for calculating slope?

I am quite new to the hydrology toolset in ArcGIS and thought it may be useful for extracting slope data from a raster. I was wondering if anyone had experience trying to extract slope data upslope ...
2
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1answer
72 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 ...
2
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1answer
2k views

Watershed Analysis using DEM [duplicate]

I stumbled upon your question regarding the mosaic feature in qgis, the thing is I'm also using Quantum and this is my first encounter with GIS this semester, so if you can please help me with a ...
2
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0answers
132 views

Error when using r.watershed

When i am calculating LS Factor using Grass r.watershed the error "Raster map or group not found" (image below) keeps turning on. I don´t understand why this error happens if i am using a elevation ...
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227 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 ...
2
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0answers
325 views

Watershed Segmentation SAGA-GIS

I'm trying to segment a topographic map to vectorize it. I'm using the watershed algorithm of SAGA-GIS. It's working fine with polygons, but with roads or contour lines is not working properly. Here ...
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438 views

Stream Order: Strahler vs Shreve

I am writing a research paper on watershed delineation and I am looking for experiences/opinions/authoritative answers on: What guides a hydrologist when it comes to choosing between Strahler's ...
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0answers
74 views

How to join two fields after calculating?

I have been working with two layers and I am trying to join them and turn them into a raster data. The first layer is a watershed layer which I have assigned each shed a location from the center point ...
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0answers
710 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 ...
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1answer
71 views

Combine drainage streams and watersheds [duplicate]

I have a question regarding ArcMap. Lets say I have a .shp with watersheds and a .shp with drainage lines. How can I combine both, so that I can display single watersheds and the length of their inner ...
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2answers
564 views

Calculating watershed runoff with landuse and rainfall data?

What is the method for computing rasters of total rainfall of a given month, flow accumulation, and land use (runoff coefficient) or soil K factor? I am using ArcMap 10.
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102 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 ...
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1answer
18 views

Is there a way to automatically find errors made by the Watershed tool?

I've delineated the watershed of near 7000 reservoirs with the Watershed tool in ArcGIS 10.1 and converted them in polygons. As you can see in the image bellow, some mistakes were made because the ...
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1answer
62 views

Watersheds tool does not create watersheds in ArcMap?

I`m trying to create watersheds and every time I run the Watershed tool, the result will be very interesting. I use snap raster and I set the extent of the output to the extent of the flow direction ...
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1answer
87 views

Writing Variables Values into Feature Class Table in ArcGIS Modelbuilder

I am trying to use the ModelBuilder for my master thesis. What I want to do is: 1) Create two new fields in a watershed feature class (contains several watersheds) 2) Use the watershed feature to ...
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1answer
484 views

Is there a SWAT model integration for QGIS?

I am trying to use SWAT (Soil and Water Assessment Tool) for watershed management activities. It is a set of commandline tools and needs a complex set of input data some of which can be generated from ...
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1answer
571 views

How to indicate flow of a watershed feature?

While tracing and digitizing rivers, streams, rivulets, etc., is it possible to indicate the direction/flow in the shapefile on QGIS? I'd like to avoid using map labels. Ideally, when done tracing, I ...
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1answer
109 views

Managing large number of catchments/watersheds

Does anyone know of an easy way to manage a large number (10,000's) of catchments/watersheds? I have defined a stream network and for each segment, I have a corresponding catchment (in a unique ...
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1answer
123 views

What is the 'water retention capacity' tool and how is it used?

In the latest version of QGIS, I found a geoalgorithim in the processing toolbox that will generate 'water retention capacity.' I am familiar with DEM-based hydrologic modeling tools in QGIS, but I ...
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1answer
31 views

Mean watershed slope - are there better methods than taking the mean of the contained slopes?

I am wondering if there are better methods for determining the mean watershed slope, other than taking the mean of the slope values contained within the watershed? For example, could or should one ...
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52 views

Simulate water runoff to get water height over each pixel of DEM

Here is my problem that I am trying to deal with. I have given a height map of around 512X512 resolution(It is Geo-referenced and I have the meta-data for this). And I have given that this area ...
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42 views

Extract a specific vertex

I am trying to create catchments/watersheds for each line segment in my stream network. I've managed to get the coordinates for all of the end nodes of the line segments to use as pour points. However ...
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1answer
22 views

Does Scimap work with QGIS?

Does anybody know if Scimap ( http://www.scimap.org.uk ) works with QGIS? I know it is supposed to operate with ArcGIS and SAGA but as I am very much a beginner with QGIS I would like to know if its ...
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32 views

Best Watershed and Hydraulic Models, What is your recomendation?

I am looking to model phosphorus, nitrogen and sediment loads at the watershed and sub-watershed scale in Southern Ontario where the primary land use is agricultural. What is the best model to use? ...