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.

learn more… | top users | synonyms

3
votes
2answers
64 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
2answers
79 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 ...
3
votes
1answer
127 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 ...
3
votes
1answer
517 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
40 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 ...
1
vote
1answer
69 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 ...
0
votes
1answer
63 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
60 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
25 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 ...
0
votes
1answer
708 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 ...
3
votes
0answers
70 views

Extract representative slope profiles from hillslope polygons

With the help of the Whitebox Geospatial Analysis Tools I was able to easily extract hillslopes from a river network in combination with a flow direction map. Now I would like to extract ...
3
votes
0answers
311 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 ...
3
votes
0answers
147 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 ...
3
votes
0answers
124 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 ...
3
votes
0answers
214 views

Pipe Network: Computing the inflows for systems with multiple reservoir (input source)

Let's say, for the sake of simplicity, we have the following Y Shape water pipe network: S1 and S2 are the reservoirs ( input source), Sout is the water demand where water is drawn out for ...
2
votes
0answers
70 views

ArcGIS - Flow Direction (Algorithm)

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, ...
1
vote
0answers
32 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
vote
0answers
26 views

How to load “soil types” in QGis?

I want to show soil transmissivity per pixel. Thus, I determine water holding capacity of each pixel (ignored other effective parameters). Respectively, I wonder, What is the soil data format and How ...
1
vote
0answers
49 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
vote
0answers
52 views

How to do a flood simulation without flooding the whole area and covering surface structures (with DEM)?

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 ...
1
vote
0answers
46 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 ...
1
vote
0answers
24 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
0answers
66 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 ...
1
vote
0answers
127 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 ...
1
vote
0answers
274 views

Morphometric and hydrological analysis with Python and ArcGIS

How can I write a program using python, that calculates some morphometric and drainage indexes using numeric attributes in the attribute table with ArcGIS? The data I have in my table are area and ...
0
votes
0answers
11 views

NDVI for natural region

I have a question about remote sensing, I appreciate that if somebody can answer to me. I have remote sensing data which I have got from landsat 7. The area which I am working on is combination of ...
0
votes
0answers
60 views

Depth of run-off water

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 ...
0
votes
0answers
37 views

How to decide when flood started depending on the rainfall data?

I created a raster with the point values (mm) of rainfall data by interpolation in the raster menu. So I have a raster rainfall data and a DEM. With this rainfall data and a DEM corresponding to ...
0
votes
0answers
32 views

Horton Stream Order as Category for r.fixed.segmetpoints with GRASS?

I'm working with Grass GIS. I want to use v.segment to set discrete, equidistant Streampoints (starting from each mouth). Since the water network is too large, it is impossible to define the rules ...
0
votes
0answers
149 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 ...
0
votes
0answers
123 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 ...