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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Hydropower Calculation

I have assigned the elevation and the volume flow to each point at a river (with v.to.db and v.what.rast). Now I want to calculate the Elevation difference between each pair of points and then ...
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0answers
15 views

How to load “soil types” in QGis?

I want to show soil transmissivity per pixel. Thus, I determine water holding capacity of each pixel (ignored other effective parameters). Respectively, I wonder, What is the soil data format and How ...
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1answer
51 views

How to calculate “water accumulated in each cell” using QGis?

I create channel network and catchment area from a DEM with SAGA GIS. I know that flow is starting from a cell to an other cell. Firstly, a cell is filled with water and then it is starting to flow ...
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30 views

Horton Stream Order as Category for r.fixed.segmetpoints with GRASS?

I'm working with Grass GIS. I want to use v.segment to set discrete, equidistant Streampoints (starting from each mouth). Since the water network is too large, it is impossible to define the rules ...
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29 views

How to decide when flood started depending on the rainfall data?

I created a raster with the point values (mm) of rainfall data by interpolation in the raster menu. So I have a raster rainfall data and a DEM. With this rainfall data and a DEM corresponding to ...
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6 views

Morphometric analysis tutorial [on hold]

I want to analyze morphometric parameters such as drainage density,stream order,bifurcation ratio etc of a small basin area. Here I want to use SRTM dem and arcgis tool. Please share if any one have ...
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1answer
26 views

Calculate River Runoff Volume (Q) with GRASS

I want to calculate Hydropower between points at a River. I already created a Rivernetwork and the Accumulationmap (without weighting) with r.watershed. My next Step was to set equivalent points along ...
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99 views

QGIS SAGA Channel network error: Input layers do not have the same grid extent

I am trying to follow along with this exercise using my own DEM. I have done the first step, creating the catchment area, with no trouble. When I try to run the Channel network algorithm, however, I ...
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2answers
63 views

How to compute average slope and area-weighted average slope?

I am learning GIS for use in hydrologic analysis. Related to computation of overland flow there are two types of slope that I would like to be able to obtain from GIS. The first is average slope for ...
7
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2answers
255 views

Find headwater polygons

This is a follow up question to this question. I have a river network (multiline) and some drainage polygons (see picture below). My goal is to select only the headwater polygons (green). With ...
0
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3answers
64 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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3answers
66 views

why Input layers do not have the same grid extent in the processing, hydrological analysis?

I'm trying to generate the hydrological analysis using processing and I have already done some terrain processing using the DEM. In this moment, I'm working in he channel network but, when i assign ...
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1answer
231 views

D8 algorithm to get the flow direction in ArcGIS

I am using ArcGIS 10 for the get the flow direction from DEM. I wonder about the algorithm they have used while calculating flow direction. It is mentioned there that it is using D8 model. D8 model ...
2
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0answers
52 views

ArcGIS - Flow Direction (Algorithm)

I am curious about the algorithm of Flow Direction in ArcGIS. Recently I am studying about Hidrology, and I have some questions regard to Flow Direction in GIS. The size of this cell is 100m x 100m, ...
0
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1answer
612 views

Calculating longest flow path and avg. slopes for catchments with qgis?

I am a hydrologist and their are 2 important pieces of information I need for modeling. I need to know the longest flow path for each sub catchment in my area of interest and I need to know the ...
3
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0answers
52 views

Where to find comprehensive descriptions of tools in QGIS, SAGA, Orfeo, etc. toolboxes? [closed]

There exists a large number of tools for QGIS (e.g. SAGA, GRASS, ORFEO etc.) - however none of these have sound description of the aim of the tool, the algorithm itself, differences to other similar ...
3
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1answer
485 views

How to calculate runoff in Rainfall Analysis?

I have 30 years daily rainfall data. How can i calculate the mean monthly runoff, minimum monthly runoff and maximum monthly runoff with the available rainfall data using GIS? I would like to use ...
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0answers
43 views

How to do a flood simulation without flooding the whole area and covering surface structures (with DEM)?

I have a high resolution DEM and want to do a flood simulation starting at a river. My hope is that the water runs into historical (now dry) river channels (in which I'm interested in) at first and ...
2
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1answer
36 views

Is every cell in flowdirection draining towards an outlet

I have created a Flowdirection map in a defined catchment. I want to find out if every cell in my map is flowing towards the creek/outlet. Is there an easy way to do this? I have created the ...
1
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1answer
328 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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0answers
113 views

r.stream.* commands do not work in qgis environment

I have been working for a while with some grass commands in QGIS environment (r.watershed, r.terraflow, r.thin, r.to.vect etc) with out any problem. I haven't been able to get any results at all from ...
3
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0answers
62 views

Extract representative slope profiles from hillslope polygons

With the help of the Whitebox Geospatial Analysis Tools I was able to easily extract hillslopes from a river network in combination with a flow direction map. Now I would like to extract ...
2
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1answer
37 views

Delination of half basins or hillslopes from a flow direction map or/and a stream network

I am using the GrassGIS r.stream.extract extension to delineate a stream network with the options 'mexp' (Montgomery exponent) and 'd8cut' (Use SFD above this threshold). It works perfect so far and ...
0
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1answer
71 views

Urban Hydrology Using With GIS

I'm researching how can I create a model urban floodplain depending on rainfall. And Which programme should I use? I want to show floodplain depending on temporal and spatial distribution on study ...
2
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2answers
64 views

Merge layers and fill gaps

I have 14 layers, which are polygons. They represent the channel of a river at different periods. I need to fill the gaps that exist once I overlay the polygons, but I can't change the properties of ...
2
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1answer
63 views

Water feature growth

I have a water feature layer which includes rivers, lakes and streams. I want to create, essentially, a buffer of these features equal to that of a 50cm increase in elevation from its current ...
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0answers
36 views

create a weight raster for a hydrology analysis

I determine affecting parameters of flood flow ( evaporation,vegetation,soil type, rainfall etc.). Then, I start to analysis using Arc Hydro. How do I relate among of affecting parameters? How can ...
0
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1answer
1k views

How to find Q in m3/sec from a raster having Q in mm for hydro power calculation

I am having a raster file with runoff depth Q in mm which was obtained from SCS method. I want to calculate hydro power potential at any location on my DEM. In the formula Q is in m3/s but we are ...
2
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2answers
454 views

Spatial Analysis - Calculate a cells elevation (height) above the nearest stream cell

I have searched for some ideas on how to formulate this analysis, but have come up short. I imagine there is a pretty straight forward answer; any help would be greatly appreciates. Data: DEM, ...
2
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2answers
62 views

ArcGIS are two rasters the same? - including null values

I am working on a task to calculate Height Above Nearest Drainage (HAND) - that is the height above the nearest point along the flow path that is on a drainage - not the geographically nearest ...
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2answers
47 views

Where can I find hydroelectric generation data for the U.S.?

It is my understanding that the US Army Corps of Engineers has some hydro generation data on their various websites (divisions, districts). For example, there is real-time hydro-electric data ...
0
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2answers
42 views

Are there publicly avaiable run-off data for Africa

I was wondering if there are good publicly available dataset for surface run-off (water)? I have a rough idea that surface run-off should be some function of rain-fall and soil ...
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23 views

Interpreting some hydrology data

This is the historical feed of the Keystone dam for October 2014: http://www.swt-wc.usace.army.mil/chartbin/KEYSOct14.shtml Here is the real time feed: ...
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2answers
294 views

ToolBar icon images missing

very early build ~ zip file I am getting blank outputs for button images in a custom toolbar. Although the button information populates the dockable toolbar, they lack respective icons [see Fig.1] ...
3
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1answer
57 views

To make a map of sinkholes on grass gis

I would like to make a map of sinkholes. I have a DTM ARC/INFO ASCII GRID of Asiago Plateau and and I'm using grass gis. Does anyone know what is the correct form in grass gis?
3
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2answers
63 views

Determining steady flow in HEC_RAS 4.0

While using HEC-RAS 4.0 Beta, how to set PF1 in Steady Data Flow?
2
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1answer
58 views

Aggregating river basins

I am not a hydrologist but am providing GIS infrastructure to our hydrology department which actually doesn't use GIS very much yet. Therefore I am asking for some hydrology related insights. Btw: We ...
3
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1answer
113 views

Horton Stream Ordering in ArcGIS?

Is there a way to order streams using the Horton (opposed to Horton-Strahler) method in ArcGIS (10.2.2)? I know the Stream Order tool allows you to use Strahler and Shreve.
7
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1answer
383 views

Hydrology toolbox versus Arc Hydro toolbox?

I would like to do some watershed delineation research/development (at the County level) with our LIDAR generated DEM, after it is corrected, but am wondering what, if any, differences might result ...
0
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0answers
10 views

Difference of Archydro and Hydrology Between [duplicate]

What are differences between archydro and hydrology tools? What does ArcHydro add on hydrology tools?
10
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2answers
1k views

How to cartographically represent water flow?

I am modelling water flow on steep slopes for an erosion study. You can see from the screenshot the results from the ArcGIS-based flow analysis. To produce these flow lines, I generated a ...
5
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2answers
128 views

Is there hydrologically correct water-course data for Africa

I was wondering if there are any hydrologically correct river-channel data available for download for Africa? By hydrologically correct, I mean the topology should be correct. Connected river ...
1
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1answer
254 views

How to calculate the river slope for a lot of rivers automatically in ArcMap?

I'm working with ArcMap 10.2 and I'm pretty new in this area.. What I want to do is compute the river slope for a lot of rivers from a DTM...I know that there is a way to do it manually passing by ...
4
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3answers
164 views

Hydrology, operational rainfall-runoff models

I am trying to collect information about operational rainfall-runoff models used around the world. I hope to build database with country outline with attached information what organization is covering ...
3
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1answer
116 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 ...
9
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4answers
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 ...
4
votes
2answers
152 views

Calculating flowpaths downstream of a point

I am assessing the flood risk posed by pipeline failure. I need to calculate the likely flow-paths for flood water downstream of critical locations along the pipeline using GIS. I'm familiar with ...
13
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3answers
291 views

Account for bridge overpasses in a ground DEM to allow for water flow under the overpass

I have a bare earth DEM made from lidar data (A). It works well and has passed all accuracy tests. It is used in storm surge models. The problem we are having is on underpasses. I need to allow water ...
2
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2answers
2k views

Error running ArcHydro tools function in Arcmap

I am trying to run a function from ArcHydro tools in Arcmap 10.1; Sink evaluation. But before it can finish it returns an error message, that, frankly, I don't understand at all. It goes ...
3
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0answers
226 views

Extracting flow accumulation to stream shapefile

I would like to create a shapefile that displays the flow accumulation for a given point in a stream channel. Is this possible? My client wants a map that shows the accumulated flow/catchment area ...