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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Transfer line direction from one polyline layer to another in a stream network

I have a stream network that has been dissolved by name. In the dissolve process, it loses line direction. I need to get that back. The good news is I have the original network, which is identical ...
4
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1answer
58 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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27 views

ArcGIS 10 restricted WEIGHTED Flow Accumulation

I have a question very similar to one asked by wxfox4god on 12th June 2013 ("Arcmap 10 restrict Flow Accumulation") that was answered by whuber. (I have had to post it as a new question as I do not ...
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1answer
43 views

Evapotranspiration in Modis

I need the Evapotranspiration data for my study (The study area is located in Australia). Somebody told me maybe I can use MOD 16 MODIS actual ET estimates. I could not find this data on earth ...
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1answer
20 views

NDVI for natural region

I have a question about remote sensing, I appreciate that if somebody can answer to me. I have remote sensing data which I have got from landsat 7. The area which I am working on is combination of ...
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2answers
41 views

Mapping UK river gauges / stations

Do you know a way to map all the river gauges / stations in UK? I found some data from the Environment Agency but it lacks of the longitude and latitude. Thanks
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1answer
33 views

How do I export a line shapefile from a network downstream from a point in ArcGIS 10.1?

I'm using the National Hydrological Dataset's flow lines to trace downstream movement of water is a freshwater diversion from the Mississippi river in Louisiana. I've gotten the trace to run using ...
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0answers
34 views

Open-source tools for run-off depth calculation

I am working on modeling surface run-off (in ArcGIS 10.2) due to a rain event (e.g., 5 year rain for a duration of 30 mins.) over an approx. area of 30 km2 for which I have a DEM and necessary soil as ...
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0answers
63 views

Depth of run-off water

I am working on modeling surface run-off due to a rain event (e.g., 5 year rain for a duration of 30 mins.) over an approx. area of 30 km2 for which I have a DEM and necessary soil as well as ...
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2answers
44 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 ...
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26 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
112 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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50 views

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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40 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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1answer
47 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 ...
3
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1answer
137 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 ...
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32 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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3answers
71 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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0answers
72 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, ...
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56 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 ...
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2answers
259 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 ...
2
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1answer
38 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 ...
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0answers
71 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 ...
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1answer
41 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 ...
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2answers
80 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 ...
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3answers
107 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
79 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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1answer
66 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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153 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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46 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 ...
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2answers
46 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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0answers
24 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
51 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 ...
3
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1answer
66 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?
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2answers
83 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 ...
2
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1answer
62 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
138 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.
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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?
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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
170 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 ...
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1answer
331 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 ...
3
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1answer
139 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 ...
4
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2answers
206 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 ...
3
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0answers
60 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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0answers
334 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 ...
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1answer
164 views

How to derive stream order from vector network [duplicate]

I have a recently-updated extract from NHD High Resolution (updated in last 6 months) which means it hasn't been cranked through NHDPlus, and won't for many years to come, and thus has no Stream Order ...
1
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1answer
147 views

Using rainfall data (raster) as an input to determine stream lines in Arc Hydro?

I was wondering if it is possible to use rainfall data (raster) as an input to Arc Hydro for determining stream lines? I am learning Arc Hydo and have gone through a couple of tutorials. As far as I ...
0
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1answer
335 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 ...
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1answer
70 views

Flow accumulation raster loading in QGIS 2.4.0 with null values (but flow direction loading ok!)

I have been tasked with creating an open-source hydrology dataset for a community group. To do this I have exported the flow direction and flow accumulation rasters from ArcMap as TIFF files and then ...
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1answer
300 views

Creating weight raster for flow accumulation in ArcGIS for Desktop?

I am studying flood flow using ArcGIS for Desktop. When creating flow accumulation in hydrology, there is a weight raster. However, İf you do not have it, the programme sets its value to 1 which is ...