Questions tagged [watershed]

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

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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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1answer
445 views

Extracting flat areas and saving them as lakes using QGIS?

I would like to extract lakes and sea from a DEM (SRTM) and save them as a separate layer. Is this possible? I have tried to extract flat areas with the Raster Calculator, but that did not work.
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1answer
530 views

r.water.outlet is returning blank raster in QGIS

I am Getting error "Ignoring point outside computation region: 77.0072,12.2529" while deliniating watershed using r.water.outlet in QGIS. What am i doing wrong?
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2answers
1k views

How to create a reservoir for a dam site?

I have created the watershed for a proposed dam site point using SRTM 90m DEM. Now my task is to create a reservoir or pondage where water would be collected from the watershed. Above a watershed can ...
2
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3answers
3k views

Automatic Watershed Delineation in ArcGIS Desktop and Arc Hydro?

I am trying to delineate watersheds automatically using Arcgis/Arc Hydro. I got the drainage area contribution of stream segment (part of stream) as shown in figure stream. The corresponding drainage ...
2
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2answers
199 views

How to create “roof line” for a general polygon area?

I have a polygon with an arbitrary shape ( assume that it is well-formed with no self intersection, no duplicated points etc), and I need to subdivide the polygon into sub-polygons like how one would ...
2
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1answer
342 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
1k 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 ...
2
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2answers
766 views

Storm Water flooding [closed]

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
52 views

Watershed issue

I am attempting to create a catchment of Danube. So far I have used the r.fill.dir to create a depressionless map and flow directions. Thus, I am now looking to use r.watershed to create stream ...
2
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1answer
53 views

Attributing stream segments based upon road intersections and stream confluences

I am currently working on attributing nodes along some stream polylines. The attribution is supposed to include: 1)length of the stream from it's reference point 2) the location of the node in ...
2
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1answer
355 views

Calculating 3D surface area base on slope in ArcGIS Desktop? [duplicate]

How can I calculate 3D surface area base on slope in GIS for each morphological units in watershed?
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1answer
425 views

drainage basin for whole lake QGIS 2.18.7

I am currently facing a problem. Over the past week, I have been initiated to hydrology within the GIS environment and have finally successfully generated water basins (using the GRASS r.water.outlet) ...
2
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1answer
171 views

r.watershed basins at coast / ocean lines

I am using r.watershed to create watershed basins using a 25*25m dem. The problem I have is that basins are not always created at coast lines. I am experimenting with the parameter "minimum size of ...
2
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2answers
832 views

What are the meaning of Grass drainage direction values from r.watershed

In Grass r.watershed the D8 drainage directions generated from r.watershed are -8. -6.-4.-2, 2, 4, 6, 8 (-1 No Data) What actual directions are these? For example in ArcGIS I know 128 is up and so ...
2
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1answer
45 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 ...
2
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1answer
65 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 ...
2
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2answers
873 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
322 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 ...
2
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1answer
279 views

Calculating floodplain for river section using DEM only in ArcGIS Desktop?

I'm looking to create areas where water might go when a river floods its banks. I have a pretty good resolution DEM (5ft^2 for each "square"). I'm not looking for anything super accurate or precise ...
2
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1answer
65 views

Spatial analysis on raster in order to get watersheds of approximate 2 ha size

I'm trying to analyse a raster in order to get watersheds at approximate 2 ha size, using flow direction/accumulation. I've been using the steps outlined below, with initial conditions for cells ...
2
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1answer
266 views

Smoothing/Aggregating polygon in ArcGIS Desktop?

I have this one big polygon separated by a big gap/space like this Can anyone advise how can i edit, so that the space should be narrow, smooth without a big gap like this? What function should i ...
2
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1answer
43 views

How do I know topo layer contains DEM-altitude? ArcMap 10.3

How do I know if a topographic layer contains DEM-altitude? ArcMap 10.3
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1answer
235 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 ...
2
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1answer
851 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
4k 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
16 views

Variations in the number of Sub-Watersheds delineated by various tools [closed]

I have demarcated sub-watersheds using different tools like ArcHydro, ArcSWAT, and Hydrology tool (ArcGIS). The same input data have been used in all tools. There are 35 watersheds derived using ...
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0answers
385 views

Watersheds and Catchment delineation in Earth Engine only with included datasets

Is there a possibility to derive Watershed boundaries or catchment areas by using one or more of the integrated data sets in google earth engine? The available data sets are: WWF HydroSHEDS ...
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0answers
40 views

Why difference in delineation of watershed by two online watershed modeling tools?

I am using two online watershed delineation tools- eRAMs and Model My Watershed (MMW)- to auto delineate watersheds using water quality monitoring sondes as my outlet points. I have three pieces of ...
2
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1answer
371 views

Watershed Delineation Loop - r.water.outlet resulting in NAN area while snapped

I am attempting to create multiple watershed delineations for stations within a CSV file. I have files for flow direction (raster with a cell size of 30m), flow accumulation(raster with a cell size of ...
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0answers
49 views

Converting data collected at political units (eg. census tract) to new ecologically-defined units (eg. watershed)? [closed]

I have socioeconomic status (SES) data of every health authority (HA) in the province. I overlay a watershed boundary polygon on top of multiple HAs and would like to know: What is the SES of the ...
2
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0answers
484 views

Getting huge range of values when using Flow Accumulation tool in ArcGIS Desktop?

I'm trying to use ArcGIS Desktop to delineate watersheds for a series of sampling sites. I've been following the protocol laid out by WhiteboxDev in General steps to create watershed boundary in ...
2
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0answers
78 views

Comparing areas of two raster files [closed]

I need to compare the areas of two rasters for calculating the percentage parts from another. For example, I have one raster file which shows separated agriculture fields. The value of each field is 1 ...
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0answers
322 views

Using “snap pour point” to find a watershed of specific area starting from a point [closed]

I am trying to find everything downhill of a certain point in order to create a watershed of a specific area. For example, say I have a point at (x,y), and I'm interested in creating a watershed ...
2
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0answers
101 views

GIS or Remote Sensing technique to map sub-surface features?

I am trying to delineate agriculture tile drainage in Midwest. Does anyone know of any GIS and/or sub-surface remote sensing techniques to detect tiles/objects buried in shallow depth of soil? Does ...
2
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0answers
649 views

Delineate watershed using manual points in RSAGA

I'm currently trying for an automated solution to delineate watersheds within a large basin. I have a collection of locations (X,Y coords) for various tributaries reaching a larger river, and the end-...
2
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0answers
620 views

Delineating watershed using ArcGIS Spatial Analyst [closed]

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; ...
2
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0answers
814 views

Watershed Segmentation in SAGA-GIS [closed]

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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3answers
692 views

Doing watershed delineation properly using ArcGIS Desktop?

I am using ArcGIS Desktop 10.2. I have the contours and the stream in AutoCAD Civil, after converting to a shapefile, I exported them in GIS, after I created the TIN from the contours below: ...
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2answers
6k views

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 ...
1
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1answer
6k 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 get ...
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1answer
587 views

How to design a flood with water elevation on a specific point?

Actually I have to know the flooding area caused by a rise of the water level due to the implementation of a dam. So I would like to know if there is an extension or any tool in QGIS or GRASS which ...
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1answer
791 views

Calculating watershed using snap pour points?

I am trying to calculate a watershed layer and have followed instructions from this previous question: General steps to create watershed boundary in ArcGIS Spatial Analyst? I have combined all these ...
1
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1answer
328 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
2k 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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2answers
294 views

How to calculate area of the output of r.water.outlet?

I wrote the following code to use r.water.outlet module in GRASS GIS: import os import sys #set up GRASS environment variables sys.path.append(os.path.join(os.environ['GISBASE'], 'etc', 'python')) ...
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1answer
408 views

Calculating mean altitude of watershed for each cell of DEM?

I have a DEM of river basin, and I need to create a raster where the cell value will be the mean elevation of watershed of this cell. I have calculated watershed area (flow accumulation x cell area). ...
1
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1answer
323 views

Python code to select streamlines within selected watershed

I'm trying to calculate total stream length for multiple, overlapping watersheds (i.e., each watershed contains the watersheds upstream of it). I have a flowline layer that I've run through the ...
1
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1answer
161 views

Large Scale Watershed Delineation

Using QGIS,I attempted Africa's watershed delineation taking the following steps: Downloaded DEM from earthexplorer USGS (GTOPO30) Created a mosaic of the downloaded DEM Reprojected the mosaic ...
1
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1answer
52 views

Extracting the z-values of a stream in a watershed if I have the values of the contours

I have the z-values of the contours (physical contours) of a watershed in AutoCAD civil, but I may use them in ArcGIS 10.2 and I have already created a DEM. I need to extract the z-values for the ...