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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4
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1answer
1k views

Mapping latlng values to a point on a HRAP grid

I have a copy of some NWS rainfall data loaded into a PostGIS database. Given a lat lng point, I want to find the rainfall for that given day. The original data are in XMRG format and projected in ...
6
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5answers
8k 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 ...
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1answer
1k views

Which flow routing algorithms does ArcGis support?

Other than standard D8 are there support for multiple flow algorithms like FD8, DEMON, Dinfinity etc?
3
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6answers
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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 System....
1
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1answer
306 views

How to estimate flow paths between contaminant sources and catchment offtake (exposure point) at catchment?

I am trying to estimate flow paths between contaminant sources and the catchment offtake (exposure point) at the catchment. Can anybody give me some help in how to proceed?
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2answers
162 views

viewshed analysis for observers wearing visors?

I'm starting with a DEM, and looking to identify every point that can be directly "seen" from any point in a particular polygon on an overlaid layer defining an area on that DEM - like any other ...
1
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1answer
212 views

Determining Pixel-by-pixel Catchments in ArcHydro

I used ArcHYDRO to prepare HydroDEM (5m) without sinks, Flow direction (FDR) raster, flow accumulation raster (FAC). As I understand FAC, value of pixel shows number of pixels that contribute to this ...
3
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5answers
9k 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 ...
2
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1answer
329 views

Inland / crater watershed delination

Even though watershed delineation is a quite popular matter here, I have what seems to be a somewhat unusual demand. I start with a DEM which is constituted of a series of craters, all centered on ...
9
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2answers
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How can I get weighted Flow Accumulation to deal with negative values? [duplicate]

here's one I haven't seen anywhere, to my surprise. I am trying to do something a little different with Flow Accumulation, which I would think has been attempted before, but it's stumping me for now. ...
2
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1answer
263 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 ...
5
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1answer
144 views

Global Basin Delineation Across Dateline

I'm trying to delineate all river basins on a global 1/16 degree grid. The algorithm that the Basin tool in the Spatial Analyst Toolbox works well (fast) except it doesn't know how to handle the ...
5
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3answers
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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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1answer
190 views

Support for hydraulic engineering projects in QGIS? [closed]

How is a DTM used in hydraulic engineering projects when working with QGIS?
9
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1answer
369 views

How to create a branch network from several input points to an unique outlet in minimizing the distances?

I am searching a way to "hydrologically" connect upstream points to a unique downstream outlet by creating an optimized stream network as pictured below... The cummulated lenght of the stream lines ...
4
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2answers
1k views

Find locations of raster maximum within polygons: Basin Delineation

I'm trying to identify the Location (lat/lon) and upstream area of every raster point that flows into the Arctic Ocean (there are a lot so it has to be fully automated). I'm starting with the ...
4
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3answers
360 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 ...
1
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3answers
3k views

Finding Catchment Area for Dam using ArcGIS Spatial Analyst?

I have a DEM of my study area, and polyline shapefile of the Dams in that area. I have run the standard Hydrology tools on it (Fill, Flow Direction & Flow Accumulation). I know that you can ...
7
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1answer
7k 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 ...
2
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1answer
1k views

How to know if flow accumulation map reflects true catchment areas?

I have calculated flow accumulation (img file) using this DEM (img file), which is 0.5 degree resolution, using arcmap. I am wondering if the cell accumulation value can directly be translated into ...
3
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1answer
682 views

Calculating Mean Upslope slope, curvature, etc

I'm trying to generate rasters whose values summarize the mean value of a given parameter (slope, curvature, etc.) of the upslope terrain. I feel like this should be doable using only a flow ...
10
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4answers
9k 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?
3
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0answers
156 views

Which geostatistical tools to use to determine surface changes over 40 years?

I have a data from the Weather station with SWEmax (snow water equivalent) collected over 40 years. I need to interpolate the data over my river's watershed and then, somehow, determine the ...
4
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0answers
493 views

Proper use of Modulus “%” operator in ArcMap [closed]

Objective: Gather pour points to define a specific-sized watershed. In this case, 1000 pixels. (for this thought exercise, watershed is to mean any point that flows through a pour point, regardless of ...
4
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1answer
6k views

Water Flow Analysis in ArcGIS Desktop?

If I know that 10,000+ gallons of water were going to be dropped at a single point how could I model where it would flow. I would prefer something that worked in ArcGIS and could create a layer.
2
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2answers
375 views

River drain: r.watershed to vector is not working

I want to vertorize the result of r.watershed (accumulation). After using r.to.vect I got the message that I have to use r.thin before. So I did, but the message comes again and again. What I am ...
3
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2answers
1k views

Can anyone point me to a dataset (shapefile or other format) for the North American Continental Divide?

I'm looking for a more detailed dataset than the 1:2,000,000 shapefile available from the National Atlas, preferably one suitable for use at 1:24,000.
4
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1answer
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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 ...
0
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1answer
3k 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 ...
10
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2answers
6k views

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

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, ...
3
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1answer
425 views

Looking for Fortran code calculating drainage basin area

I am working in a project of glacier mass balance. For my project I want to integrate the area of the drainage basin in a glaciological system model (GSM). As the drainage area changes with time due ...
2
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2answers
2k views

How to speed up batch watershed delineation?

I have a large number of pour points - approximately 250,000 for which I want to delineate the upstream watershed area using ArcHydro's "Batch Watershed Delineation". Given that it takes roughly 4-5 ...
4
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0answers
227 views

Assigning attributes from hydrologic sinks to upstream features? [closed]

I have a large hydrology geometric network with more than 300 sinks and roughly 150 barriers. I'd like to have the SinkID added to the attributes of the barriers (some individual networks have a ...
5
votes
1answer
689 views

How do I get the upstream distance to all points in a DEM from a single downstream point?

I want to get the upstream distance to all points in a DEM from a single downstream point. The goal is to create a "downstream distance to a point grid". This then would allow me to create "distance" ...
6
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3answers
3k views

How to determine elevation drop along stream with ArcGIS Desktop?

I need to calculate(estimate) hydraulic head(elevation drop) along a single river stream in order to find potential site for small hydropower plant. I have a DEM with 20m resolution and raster and ...
2
votes
1answer
77 views

Where can I obtain Water Virtual Flow Segments for Minnesota?

This is a cross-border task. I already have this data for Ontario, Canada but I also need to complete the model for a large lake that is essentially split in half between the two countries. ...
4
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1answer
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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 ...
0
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0answers
929 views

Watershed / drainage network analysis; floating point or integer raster for input?

I am a little desperate to find a solution to my problem. As I have detailed in this post I am unable to create a detailed drainage network (and catchments) from high resolution LiDAR data. I think ...
29
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7answers
18k 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 data....

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