Questions tagged [hydrology]

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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3
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2answers
167 views

How to plan preservation of wetland using a DEM and ArcMap?

I'm trying to plan a wetland preservation. This is the DEM I have: My aim is to hold as much rainwater as possible in my area of interest (red poly) by building (as few as possible) new and raising ...
4
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2answers
840 views

Get upstream sections of a network

Is there any extension to get all upstream sections of a polyline shapefile which represent an hydrographic network in QGIS? It could work like this: you choose a specific branch and a direction ...
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0answers
459 views

Why does the flow direction tool in ArcGIS desktop give wrong output (unique values from 1-255)?

I ran the flow direction in ArcGIS, and received unique values ranging from 1-255. I know that these values are wrong, and should be along the lines of 1, 2, 4, 8, 16, etc multiples. The DEM is ...
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2answers
925 views

Correcting Errors in Height Above Nearest Drainage (HAND) model

I have used this tread Spatial Analysis - Calculate a cells elevation (height) above the nearest stream cell to create a HAND map in ArcGIS. First I used the hydrology toolset to fill in sink in the ...
1
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0answers
325 views

Measuring river width every mile in Google Earth?

Given an area, can Google Earth tabulate the width of a particular river? This problem I think requires using an API to programmatically: define an area of interest identify a terrain feature like ...
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0answers
46 views

How to join hydrological data from a big area with a small area with better pixel resolution?

I use TAUDEM to make hydrologic analysis. I have a hidro 1K dem file from South America (big area) pixel resolution=1000x1000 meters. I have a specific dem file located in Brazil (small area) pixel ...
2
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1answer
150 views

Connectivity of Streams

I have a line vector layer containing streams (see image below). What is the easiest approach to determine the connectivity of each stream segment (eg. sum of upstream nodes)?
4
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1answer
1k views

How can I select all streams downstream of a polygon

I have an ordered stream network and I want to select all stream features that contain water that has come from a certain area. To start with I'm running a select by location query to find all stream ...
4
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4answers
2k views

Identifying highs on DEM using ArcGIS Spatial Analyst?

I have a DEM and I want to find each hill and create a polygon for its area, effectively the out closed contour that encloses the hill. I can do this visually but I'm about to work on a larger area so ...
2
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1answer
571 views

Batch processing Surface volume calculation in ArcMap?

I'm trying to collect the 2D area, 3D area and volume of a given basin at 0.5 meter increment in plane height, but since I want to graph the relationship between plane height and the areas and volume, ...
0
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1answer
241 views

reading GRASS vector map in python

I know similar questions have been asked several times, but none of the solutions seems suitable for my problem or don't work.. I computed flowlines using the r.flow tool from GRASS GIS, then I ...
2
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1answer
301 views

How do I find out the sea levels?

I have following elevation data of a region (the higher the altitude, the brigher the points): How can I find out, which areas are filled by water, and which not? Can I assume that if the elevation ...
5
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3answers
528 views

Ways to determine winding topographic characteristics of a river

Are there any methods and/or technical guides on how to classify the degree of winding of river bodies? I have the following polygon layer of roughly 100,000 water bodies and would like to write an ...
4
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1answer
158 views

Watershed Tool Straight Edge Problem

I'm trying to accurately delineate a watershed into sub-basins using dams as pour points. I'm using the hydrology toolset, but I can't seem to get rid of straight edges that are along some of the ...
6
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1answer
983 views

How to run a tool from Whitebox GAT in ArcGIS?

I have a series of tools that I need to run in ArcGIS to hydrologically condition my DEM, but the first step in this process is running the Breach Depressions tool from Whitebox GAT (I have found that ...
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0answers
128 views

Automatically selecting main rivers of very branched river network using Arc Hydro? [closed]

I'm using ArcGIS 10.1 for Desktop and Arc Hydro. Is there any way to automatically select the main rivers of a very branched river network?
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0answers
795 views

How can we extract the stream order branch?

Actually I am new to GIS, so I don't know much about technical terminology. I have extracted a river network but now have a problem in distinguishing the branch order of stream (from order 1 to 2, 2 ...
4
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0answers
226 views

SAGA hydrological analysis in QGIS 2.8 on Mac

I am running QGIS 2.8 on a Mac machine and I want to calculate the catchment area using SAGA - Catchment Area. It starts running but after a while when QGIS wants to open the generated files there is ...
1
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1answer
2k views

Automatically generating pour points along stream network?

The following screenshot shows the results of a water flow analysis where I identified stream order via the Strahler method in ArcGIS. Now I need to generate watersheds for 2nd order streams and ...
1
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0answers
105 views

Hydrology Analysis via SAGA - what is the unit? [closed]

I did a couple of analysis via SAGA about an area in Iceland...I've never worked with SAGA before, could anyone tell me what Units the numbers in the legends for "Catchment Area Recursive" and "...
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0answers
607 views

Problem in running r.sim.water

I am trying to run the r.sim.water in GRASS. I have calculated the partial derivatives dx and dy rater map using r.slope.aspect. I am using this elevation map [1] to get the time-series depth map. But ...
1
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1answer
957 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 ...
3
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2answers
244 views

How to calculate the impact and extent of damage of a potential tailings dam breach with ArcGIS?

I would like to be able to delineate an approximate area of a potential tailings dam breach for an emergency response plan purposes. The tailins dam and pond have not yet been built. The data I have:...
6
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1answer
547 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 ...
2
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0answers
170 views

ArcGIS 10 restricted WEIGHTED Flow Accumulation [closed]

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 ...
2
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1answer
2k 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 ...
0
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1answer
98 views

NDVI for natural region

I have remote sensing data which I have got from landsat 7. The area which I am working on is combination of farms and natural area (Bare earth; without any vegetation). I want to estimate the ...
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4answers
540 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.
0
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1answer
542 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 ...
1
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0answers
169 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 ...
1
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0answers
576 views

Depth of run-off water [closed]

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 land-...
1
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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 ...
4
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1answer
1k 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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0answers
143 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 ...
1
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1answer
851 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 ...
5
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1answer
4k 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 ...
0
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1answer
131 views

Discrete waterpoints with GRASS [closed]

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 ...
3
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0answers
522 views

ArcGIS - Flow Direction (Algorithm) [closed]

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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0answers
526 views

Simulating flood without flooding whole area and covering surface structures (with DEM)? [closed]

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 ...
8
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2answers
388 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 John'...
2
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1answer
44 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 ...
3
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0answers
169 views

Extract representative slope profiles from hillslope polygons

With the help of the Whitebox Geospatial Analysis Tools I was able to easily extract hill slopes from a river network in combination with a flow direction map. Now I would like to extract ...
3
votes
1answer
324 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 ...
2
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2answers
872 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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4answers
4k 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 ...
0
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1answer
203 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
205 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 boundary....
2
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1answer
2k 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 ...
1
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0answers
205 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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2answers
90 views

Are there publicly available 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 infiltration/...