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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2
votes
2answers
45 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 ...
1
vote
2answers
38 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
votes
1answer
436 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 ...
0
votes
2answers
36 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 ...
1
vote
0answers
17 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: ...
1
vote
2answers
194 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] ...
2
votes
1answer
37 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?
2
votes
2answers
58 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
votes
1answer
47 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
votes
1answer
56 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.
0
votes
1answer
503 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 ...
7
votes
1answer
273 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
votes
0answers
9 views

Difference of Archydro and Hydrology Between [duplicate]

What are differences between archydro and hydrology tools? What does ArcHydro add on hydrology tools?
10
votes
2answers
916 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
votes
2answers
89 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
vote
1answer
111 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
votes
3answers
158 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
votes
1answer
91 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
votes
4answers
789 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 ...
3
votes
2answers
79 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
votes
3answers
255 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
votes
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
votes
0answers
105 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 ...
2
votes
1answer
123 views

Negative Topographic Index Values

I am getting negative topographic index wetness values in SAGA GIS - anyone else every get this? Not all negative values, but the minimum of the TWI range is negative for some steep watersheds we are ...
3
votes
0answers
43 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 ...
1
vote
1answer
69 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 ...
1
vote
1answer
72 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 ...
4
votes
5answers
1k views

Calculating Runoff / Streams using DEM in ArcGIS

I am just curious about the workflow that many of you use for runoff/stream analysis using a DEM and create a "water network" from the results in ArcGIS 10.1? I know the average rainfall for different ...
7
votes
2answers
2k views

How to calculate stream order for vector data without a DEM?

I have a shapefile which contains the streams that were digitized from a satellite Image. I would like to calculate the stream order for this data. The data does not exactly match the DEM that I have, ...
1
vote
1answer
97 views

How to use ArcMap for HydroPower Potential

I am trying to determine the sites for small hydropower. I have a elevation dem, rainfall data, Curve number data (from soil and landuse shapefiles). I have already used the DEM to fill sinks, find ...
21
votes
2answers
2k views

Proper workflow for LAS to DEM conversion

I regularly come across LiDAR (.LAS) files with elevation data. When I do, I always struggle to find a way of converting them to a DEM for hydrological analysis. I have developed several workflows, ...
1
vote
1answer
51 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 ...
1
vote
1answer
97 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 ...
4
votes
1answer
257 views

Generate channel network (rainwater run off) - which algorithm is the best?

I want to compute DEM for a whole country (cca 79 000 sqr. km) and I need to be hydrologically correct as much is possible. After, for this correct DEM I need to compute drainage lines of surface ...
1
vote
0answers
56 views

Determining uppermost point in stream based on gradients?

I am trying something new and was hoping someone out there may have done this same process or something similar or may have a best approach. For this particular project I am working with ArcMap ...
0
votes
0answers
70 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 ...
1
vote
0answers
77 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 ...
4
votes
0answers
114 views

Flow direction generated for river is incorrect

I am trying to generate a hydrologic model and I can not really proceed on the next processes. I have this problem on generating flow direction. I have already executed fill sinks and the next is flow ...
9
votes
4answers
5k views

Tutorial on how to model flooding using data from gauging stations along rivers in QGIS?

Can someone please direct me to a tutorial where I can learn more about how to model flooding using data from gauging stations along rivers using QGIS?
0
votes
2answers
84 views

r.topidx error: required parameter output not set

I'm calling GRASS r.topidx from QGIS 2.2.0. I can get other tools to work on the DTM, for example r.watershed. But r.topidx I get the Oops message: Oooops! The following output layers could not be ...
1
vote
2answers
55 views

Divide stream segment at specific point

I have a stream network and outlets as shown below. It is overlapped with outlet cells raster which I can use to get sub-watersheds but when I add an outlet (red color cell in current example) then ...
4
votes
1answer
781 views

Assigning points to their respective Reaches using Stream Gradient?

This is a continuation of the question I initially posed here. Also, I've attached a shapefile on my Drop Box account here. I'm trying to break a stream network up into 100m reaches, assigning ...
5
votes
4answers
386 views

What satellite imagery would help to show spring locations?

I've got lots of tiny streams on a hydrography shapefile. Historic texts indicate that certain ones have headwaters at "sources" or springs, and I want to try to find these. Browsing the historical ...
5
votes
1answer
389 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 ...
2
votes
1answer
175 views

Dissolving stream orders using Python rather than VB script?

I've been trying to dissolve streams, using orders programatically and I came across this VB script. The reason is that if I use ArcGIS dissolve, it merges the confluence of the same orders. I would ...
0
votes
1answer
58 views

How are minor tributaries determined?

What are the criteria to determine if river A is a major or minor tributary to another River B? Is stream order the only deciding factor i.e. the highest order is the main stem, one less order is a ...
0
votes
1answer
47 views

Problem for slope map

I want o create one slope map for my model but I have one big problem. I have contours lines and mass points and I create a DEM using topo to raster but if I want to create a slope map from that DEM I ...
0
votes
1answer
111 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 ...
1
vote
1answer
168 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 ...
0
votes
1answer
41 views

How much precipitation must fall within a catchment area to fill up a sink’s entire volume assuming that the runoff conditions are perfect

I am perfoming an exercise and I need to answer these question, any hints would be extremely useful. How can it be calculated how much precipitation that must fall within a catchment area to fill up ...