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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How to determine drainage area upstream from point?

I do not know how to come up with the drainage area (km squared) upstream of Lat 77.84, Long -30.96. I have converted my contour shapefile to a raster, identified and filled the sinks and then created ...
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37 views

Unusual results with Watershed geoprocessing tool

From the starting point of that I already have a flow direction raster and a pour points feature class, I get different results if I execute the geoprocessing tool Watershed using as input the raster ...
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1answer
62 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 ...
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52 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
24 views

Calculating number of streams of each order in watershed using ArcGIS Desktop?

I obtained the order of watershed using arcgis as 7. I want to know the number of streams of each order so as to verify horton's law. Is there any tool for it?
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67 views

Discrete Waterpoints with Grass

I've been working with Grass GIS for about two months. I have to develop a method for the identification of target regions of small hydropower plants. Boundary conditions are a predetermined minimum ...
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65 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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21 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? ...
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1answer
38 views

How to fix this “Sorry <1> is not a valid option” in GRASS-Ubuntu using r.water.outlet?

I am working with this .sh code (a while loop, extracted from: http://www.surfaces.co.il/) to create watersheds from drainage raster and outlet point of every watershed, but I obtain this error: ...
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1answer
146 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 ...
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3answers
228 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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20 views

GRASS GIS 6.5SVN : r.watershed failed to display basin and accumulation maps

I am passing DEM and threshold values as inputs.I want to get basin and accumulation as outputs.I tried it in Grass,process was completed.while dispalying result it is showing white screen (both ...
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1answer
132 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 ...
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2answers
411 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 ...
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1answer
57 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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1answer
95 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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1answer
108 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 ...
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1answer
100 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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118 views

ArcGIS ModelBuilder Clip Raster by Polygon Error

My task is to derive the hypsometric integral and hypsometric curve for a lot of drainage basins. Since it is very time consuming to do this manually, i have created a model (with help from this ...
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46 views

QGIS DEM Output cell size does not match DEM input cell size

As my first post I offer a humble apology if this is such a basic question as to make any of you cringe. I feel like I have exhausted my search skills and read through the QGIS documentation ...
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1answer
54 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
27 views

Water Quality Data Acquisition Sources

I was wondering what sources are available, or if anyone has water quality data for the Great Lakes and specifically Lake Ontario. We are interested in mapping Phosphorus, Organic Matter, Nitrogen and ...
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1answer
779 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 ...
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1answer
347 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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2answers
714 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 ...
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1answer
51 views

River channel is cut after rendering flow accumulation in hec-hms

I'm trying to generate flow accumulation using hec-geohms and I have already done some terrain processing using the DEM. I was really confused what happened, why has the river channel been cut? ...
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1answer
148 views

import parameters for r.watershed - (watershed basin analysis program) tool from grass using Qgis 2.2

I want to run this tool from Qgis 2.2 but i don't know how to use the PARAMETERS to run this tool. The red frame are the PARAMETERS I don't know. Can someone to tell me what those PARAMETERS are ...
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1answer
337 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
100 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
259 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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1answer
87 views

Better ways to check if GRASS r.water.outlet works out fine output

I use my python script to call GRASS module r.water.outlet from outside, and here's my script(I perform this script in pyscripter): import os import sys #set up GRASS environment variables ...
2
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1answer
170 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 ...
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2answers
200 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 ...
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1answer
399 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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0answers
175 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 ...
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1answer
58 views

Add a field to output feature of a geoprocessing tool?

I am running the Watershed tool and RasterToPolygon tool in a loop for a number of points: flowdir = "flow.tif" flowacc = "flowacc.tif" pnts = [arcpy.PointGeometry(arcpy.Point(x=0.0, y=0.0, ID = ...
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379 views

Watershed delineation; how to program

I've been trying to roll my own watershed delineation program, taking a flow direction grid and pour points as input. I coded up a quick search algorithm in Python which inspects the flow direction ...
2
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1answer
61 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 ...
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1answer
207 views

Efficient algorithms for recovering watershed boundaries?

This is somewhat related to a previous question I asked: What Algorithm is used by ArcGIS Watershed tool? I was wondering if there is a more efficient way to calculate catchment areas if you are ...
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1k 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 ...
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1answer
2k views

How to use GRASS module to delineate watershed area?

Update#1:I changed to work under qgis 1.8, I only input the DEM file and run the r.watershed module, and I got this: I have a DEM file of one specified region, and I take the following steps to ...
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1answer
52 views

generate subcatchment starting from a DTM [duplicate]

I would like to know if there is a plug-in in Quantum GIS, which can help me to generate subcatchments starting from a DTM. Thank you very much!!!
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2answers
231 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 ...
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0answers
277 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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1answer
108 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 ...
2
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0answers
353 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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2answers
464 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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0answers
47 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. ...
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101 views

Watershed layers with names for each one for Europe or Sweden

I am working on freshwater species and I would like, make a list of each watersheds used for each species. So I am looking for a watershed maps which contain name of the watershed. I found some good ...
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173 views

What is most suitable DEM to delineate watershed (from spot height, ASTER and SRTM)?

I have three DEMs of our country which are spot height DEM, SRTM DEM and ASTER DEM. SRTM has 90m resolution and ASTER has 30m resolution. My supervisor told me to delineate watershed using these ...