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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6
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1answer
176 views

In hydrologic terrain analysis is there a difference between “pits”, “depressions”, and “sinks”?

In hydrologic terrain analysis is there a difference between "pits" and "depressions"? For instance, Planchon and Darboux (2002) state The usual numerical methods for removing the depressions of ...
3
votes
2answers
43 views

How to calculate shortest distance from start to end of river?

How can I calculate the straight distance from the start to the end point of a river (red line in image)? I don't know how to do this automatically.
1
vote
1answer
47 views

How to define pour points from a stream network at a barrier for watershed calculations?

I'm looking for a way to check if cells from one raster file have contact or get close to cells from a second raster file. For example the blue raster is a barrier and the coloured is the flow ...
8
votes
2answers
4k 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, ...
2
votes
7answers
4k views

Error running Arc Hydro tools function in ArcMap?

I am trying to run a function from Arc Hydro 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 ...
1
vote
1answer
37 views

Create a flow network from a flow direction ARC GIS

First, I created a flow_direction from a DEM, then I applied corrections to this flow direction. Now my question, how to create a flow network (order flow) from a flow direction, that I already ...
1
vote
1answer
42 views

Constructing LS factor for RUSLE without outliers using ArcGIS for Desktop?

I'm using the following formula in RUSLE via raster calculator to obtain a LS factor Power(Flowacc)*1/22.1,.4)*Power(sin(slope)*.01745/.09,1.4)*1.4 My expected outcome is a raster from 0 to ...
1
vote
0answers
22 views

Curve Number equation

I have a floating point raster of Curve Numbers (70-91) and I'm attempting to use the curve number equation to create a weight raster for flow accumulation, to determine runoff for a single rainfall ...
0
votes
0answers
55 views

Flow Accumulation weight grid

I currently have several rasters relating to Landcover Soil data Topographic Wetness Index (TWI) Slope They are all re-classed to % infiltration. I'm looking to use these together as a weight ...
1
vote
0answers
24 views

How to create an elevation profile in google earth from a kml?

I have a KML file of a stream that I originally created as a line shapefile in ArcMap (one stream extracted from a larger watershed data set). I need to create an elevation profile of this stream. ...
4
votes
2answers
854 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 ...
1
vote
1answer
192 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 ...
0
votes
1answer
1k views

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

I am a hydrologist and there 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 ...
2
votes
1answer
891 views

Getting Negative Topographic Wetness Index (TWI) values in SAGA GIS?

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 ...
2
votes
1answer
36 views

Cost Path based on Lowest Maximum Elevation Encountered

I am trying to locate the lowest elevation point at which a river will overtop its banks, and spill into lower-lying terrain behind them. I'm working in ArcMap version 10.2, and using a ...
3
votes
1answer
64 views

Issue with r.watershed run by QGIS-Python-processing.runalg

I would like to extract flow accumulation and flow direction layers from a DEM calling the grass r.watershed module from a QGIS-python script using the processing class. I obtain just an empty map, ...
0
votes
2answers
328 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 ...
0
votes
1answer
172 views

Downloading Hec-GeoHMS for ArcGIS 10.3.1?

I can't download geohms from this link http://www.hec.usace.army.mil/software/hec-geohms/. Can anyone help me to get Hec-GeoHMS for ArcGIS 10.3.1? The doesnot responds and I could not get a ...
7
votes
3answers
201 views

Calculate average stream slope at each location along stream

I'm trying to calculate the time of concentration for every point along a stream network. To calculate the time of concentration, I need the upstream channel length and channel slope. I've been able ...
1
vote
1answer
47 views

Using the watershed tool with two pour points

I have two pour points in a stream network created using the flow accumulation methodology in ArcMap. When I use the watershed tool with this pourpoint shape file, I get a watershed between these two ...
1
vote
1answer
35 views

Looking for data on river flow speeds

I'm looking for sources containing data on measured river flow speeds, any / all locations worldwide, in any format or language. Googling didn't help much.
4
votes
1answer
751 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 ...
4
votes
0answers
82 views

Determining the Thalweg line of a river without bathymetry?

I have the boundaries and centerline of a river. The Thalweg line defines the deepest elevation of a watercourse (see Image taken from Google). I do not have accurate enough bathymetry or Digital ...
2
votes
1answer
75 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)?
1
vote
0answers
26 views

Dividing stream network of specified lengths in ArcGIS for Desktop? [closed]

we are trying to find hydro power potential of river basin by using ArcGis and SWAT ,we have created stream network ,but unable to divide stream network at 500mts interval, unable to find the tool
1
vote
1answer
37 views

Hydrological model building for flooding analysis [closed]

I am recently studying the topic in investigating the features of river and to perform flooding analysis. I got the elevation data, and I used the elevation data to generate streams in ArcGIS and I ...
1
vote
1answer
56 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 I have combined all these steps and run it as one in ...
4
votes
1answer
234 views

How is “Burn Stream Slope” in ArcHydro working?

I have a DEM with only small relief and many ditches. Because of the small relief, I can't calculate flowdirections for some parts of my DEM. I know that in reality water is flowing from west to east ...
19
votes
7answers
11k views

Methodology for creating accurate drainage networks (and catchments) from high resolution LiDAR DEM?

This is not the first time I've stumbled over this issue; it seems that I am unable to generate a correct drainage network model and the resulting catchments from full resolution (1m cells) LiDAR ...
3
votes
1answer
61 views

How to delete obstacles (corduroy road) from DEM in ArcMap?

I have a DEM which looks like this: The narrow longish lift running from north to south is a corduroy road (hope this is the correct word for "planks which allow people to cross a mire without ...
4
votes
1answer
1k views

Determining direction of rivers i.e. which villages lie upstream and downstream?

I want to determine which villages lie upstream and which villages lie downstream big cities built on the side of rivers in Indonesia. I have the .shp file of villages and cities, the .shp file of all ...
4
votes
1answer
151 views

Calculating Flooded area / Inundation in ArcGIS for Desktop?

I was tasked to create a layer with the flooded areas if the sea / river level was to go up by X feet. There is no requirement to take Flow and Pour Points into account, just a simple raise in water ...
3
votes
2answers
94 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 ...
3
votes
1answer
40 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 ...
1
vote
0answers
52 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 ...
0
votes
1answer
98 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
vote
5answers
7k views

Where can I find base data shapefiles for whole US?

I am looking for the base layers for whole U.S. - roads, hydrological lines etc with flexibilities of changing symbology and labels. TIGER is a good source but it is at county level. I am running on ...
10
votes
4answers
2k 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 ...
1
vote
0answers
44 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 ...
0
votes
0answers
142 views

What is the difference between Specific Catchment Area and Total Catchment Area in hydrology?

I am getting stuck on the concepts of Total Catchment Area (TCA) and Specific Catchment Area (SCA) as I try to learn more about TOPMODEL. What do these metrics mean in hydrology? The context I ...
0
votes
0answers
209 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 ...
0
votes
0answers
22 views

building artificial dam in a canyon [duplicate]

I want to calculate the water volume dammed by a dam in a canyon. I managed to calculate the water volume but I actually need a dam in a certain place of the gorge so I can pursuit my calculations. I ...
1
vote
0answers
33 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 ...
0
votes
2answers
61 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 ...
3
votes
1answer
115 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 ...
1
vote
4answers
561 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 ...
3
votes
0answers
83 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
vote
0answers
43 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 ...
6
votes
1answer
4k views

Calculate Topographic wetness index in SAGA

i am currently working on a project which involves the quantification of the wetness in certain areas. However it produces quite different results from what i expected. I'll describe the steps i have ...
3
votes
4answers
196 views

How can Identify highs on a DEM?

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 ...