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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53 views

1:250 streams data - USA wide - where can I find it?

I have 1:250 streams data for a few western states. I find this scale to be excellent in many settings as base hydro data. I have never been able to find a USA or better yet, NA wide dataset of this ...
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2answers
2k views

Upstream to a river and tributary of a river - What is the underlying difference

What is the difference between a stream/ river upstream to a river A and a tributary of River A? I know that all tributaries are upstream to its river (A) and feeds into river A, but can there be a ...
2
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2answers
762 views

Storm Water flooding [closed]

Is there a method in Arc Gis for mapping storm water runoff in an urban environment assuming that the sewers are at full capacity. I just want to map roughly where the water will flow over the land ...
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1answer
622 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 ...
7
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1answer
2k 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 ...
3
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1answer
518 views

Verifying the number of times a line crosses other lines

I have a series of lines that represent streams. I have a stream line and two flowpath lines in one feature class and two banklines in another feature class. Total of five lines. I then have a feature ...
5
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2answers
3k views

Flow Accumulation in R

My apologies for such a general question. Is there an ArcGIS like implementation of Flow Accumulation for R? What I am trying to avoid: Using ArcGIS; Using Grass; Using RpyGEO (but will if need be) ...
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2answers
524 views

Conversion of diagonally adjacent pixels into one polygon?

I am trying to vectorize a raster whose digital numbers indicate different classes they belong to. ArcGIS and QGIS yield similar results: separate shapes out of pixels sharing the class that are ...
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4answers
4k 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 ...
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2answers
475 views

Tool in ArcGIS for stream flow analysis?

I'm just wondering if there is any tool in ArcGIS that can be used to analyse stream flow measurements. For example, estimating runoff, baseflow and baseflow index based on stream flow measurements.
2
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2answers
158 views

How to determine stream channel Reach locations?

I have a stream network and want to determine stream reach locations In attached figure, Reach 4 is at the junction of sub2 and sub5, and Reach 3 is at the junction of sub1 and sub4. Any suggestions ...
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2answers
15k 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, ...
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0answers
160 views

Determining longest length of segmented polylines representing rivers? [duplicate]

I have a series of shapefiles using polylines to represent the hydro network of a region. As you can see in the picture, these polylines go into great detail. These polylines are very segmented even ...
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1answer
2k 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 ...
3
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2answers
3k views

Spatial Analysis - Calculate a cells elevation (height) above the nearest stream cell

I have searched for some ideas on how to formulate this analysis, but have come up short. I imagine there is a pretty straight forward answer; any help would be greatly appreciates. Data: DEM, 1/...
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2answers
262 views

Determining steady flow in HEC_RAS 4.0

While using HEC-RAS 4.0 Beta, how to set PF1 in Steady Data Flow?
7
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1answer
446 views

Is there a downloadable data source for mapping out rivers with names for the whole world?

I'd like to be able to extract rivers with their names and the flow size (not direction) for the whole world. The scale I'll be drawing it at is about 2 centimeters per 10 real world km - nothing too ...
3
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0answers
537 views

Creating water surface from vector line in QGIS

I want to create a raster surface representing the flood level in a creek based on output from a 1D hydraulic model. I receive a 3D profile of the water surface in a creek line as a 3D Polyline (...
7
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3answers
3k views

Tracing up a stream network & tabulating attributes of polygons it passes through

I have an ArcGIS question that is either very easy or impossible (my favorite kind). I am somewhat inexperienced when it comes to dealing with network analysis, so maybe I'm missing something major ...
2
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1answer
90 views

Geoprocessing in 3D [closed]

I am looking for some advice regarding suitable software for geoprocessing in three dimensions. Specifically, I need to regularly undertake the following tasks: Intersect a line with a surface and ...
1
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1answer
137 views

About Interpolation Method using GIS10?

I have attached my stream network where the green dots shows the location with discharge gage now I want to create a raster all along the stream network to have a discharge data all along the river. ...
1
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1answer
320 views

postgis: problems creating flow direction polyline; not all needed connections are drawn

I am using post-gis to create a polyline that describes the flow direction of water in a landscape/catchment, to use in a hydrological model. To do that I start with a regular grid (as polygon) and ...
3
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2answers
2k views

Arcmap 10 restrict Flow Accumulation

I am working with the Flow Accumulation tool in ArcMap 10's spatial analyst hydrology tools. This tool calculates the total number of raster cells that flow into a given cell. However, for my purposes,...
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 ...
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5answers
7k 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 ...
5
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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?
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6answers
10k 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 System....
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1answer
303 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
158 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 ...
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1answer
210 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 ...
2
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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
315 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
2k views

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
255 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
141 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
3k 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 ...
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1answer
178 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
341 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
346 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
642 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
155 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
481 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 ...
4
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1answer
5k 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
329 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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1answer
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.