Stream Order from a Digital Elevation Model (DEM) using ArcGIS

hi welcome to another ArcGIS tutorial in this tutorial I will show you how to derive the order of streams using a DM using algae is a co primary GIS tool so just to give you a bit of an overview of what stream order really means I've just pulled up this webpage from USGS as you can see over here the the headwater branches which I actually below us which are actually the small streams gets ranked as number one and if two streams of of the same rank it's meets at a confluence then starting from that confluence we increase the the order from the the previous rank to a higher rank in this case you can see that it increases from one to two and so now something important to notice is that at a confluence like this if a stream with a lower order meets a stream with a higher order we still actually maintain the the order of the stream with the high order and so on this actually lets us distinguish quite easily what what are the majors what are the what are the sort of major rivers and what are the sort of contributing tributaries to the major river so that's basically the objective of this tutorial so let's get started with the DM so I'm just going to run through the basic steps of deriving the stream network which we can do through this spatial analyst tool and under the hydrology tab you can first fill your de M because there could be a sinks in the rhodium that you might download from from your website so as my input surface roster I'm just going to use my de mi row DM I'm going to name this as Phil alright now we have the field DM so I'm just going to go ahead and get rid of this row DM and next you need to generate the flow direction Ruston so go to the flow Direction option and use your field DM as your input surface roster and this one I'm going to name as flow dir flow direction rust alright now we have the flow Direction roster and the next thing that we would need is actually to identify where are the flow accumulating points which we can do by running the flow accumulation tool over here and your input is going to be your flow Direction rust as you just generated and this one I'm going to name as flow acc alright now you can see that we created the flow accumulation roster but still as you might see it's not quite visible to me because I have to do some reclassification of the flow accumulation roster so what I'm going to do is I just went to the layer properties and over the classifier tab over here instead of going with five classes I'm just going to limit myself to two classes and basically what I'm going to do over here is I'm just going to allow all the low accumulations let's say from 0 up to a certain number to be represented in black color and above from that number I would like to actually get my accumulations represented in white color for example now just by looking at these numbers I would like to maybe just play around and see let's say if I put around 5,000 over here that means from zero up to 5,000 I would like to actually represent it in black color and 5,000 upwards I would like to see it in white color now what happens when I do this is you will actually see more accumulations which is actually represented in white color now if you in case if you decide to go higher on this number for example if I put around 100,000 you are asking the program to classify you all the accumulations which are represented from 0 up to 100,000 in black color which means that it's not going to be visible visible for us this is only going to leave only the major rebel lines where accumulations are higher and that's something like this so for the for this tutorial I'm just going to actually stick with maybe around let's say around 8,000 and something to keep that in keep in mind is that this number will depend on the T on the type of DM that you are using because the accumulation values are going to be differ from one DM to another DM based on based on the area that you're actually going doing the analysis for all right I'm just going to deactivate this fill and the flow Direction layers and if i zoom in a little bit you can actually start seeing the river line [Music] quite clearly now the next thing that I'm going to do is when creating when trying to create the stream order you have to actually isolate these two classes let's say in into a into a new roster so what I'm going to do is I'm just going to use the raster calculator which you can open by just typing in rustic and I'm going to take this flow accumulation roster and I'm going to assign the flow accumulation to be greater than or equal to 8,000 and what this is going to do is if I press ok yeah now you can see that all the flow accumulations which are equal and greater than 8,000 got sort of classified into one grid code which is number one and the rest which actually less than 8,000 got classified into another color which is green so since this is not that visible I'm just going to change the colors let's say I'll keep the I'll change the color of green from green to white and this I'll probably change it to blue or something like that yeah now if you zoom in it's actually going to be a bit more visible all right now what you can do in order to generate the stream order is you can go back to your toolbox and there's this option called stream order so just double click on it and as your input stream raster you have to input this rustic elk raster which actually contains of just the values of your streams and there's another class which actually shows so I'm just going to use this rustic al-rastan as my input stream raster and over here we are asked to input the flow Direction roster I'm going to name this s stream order and the method of stream order this is actually one of the most commonly used string all the techniques Strada so I'm just going to stick with that we were able to derive the the order of the streams and over here you can see different grid codes starting from one to five and by looking at this figure I can start seeing that this in color River line is probably going to be a stream with a higher order and as you can see it's it has number 5 which has which is actually the highest order and all these small tributaries which are represented in sort of brown color has the lowest stream order so these are sort of small tributaries which are meeting much larger streams so next thing as you can see if i zoom in over here still actually this is in the form of a raster you can still see the pixels so I would like to convert this into a network of rivers but in terms of in the form of polygons so what I'm going to do is I'm just going to convert this raster into a polygon and you can simply use this tool called stream to feature or even you can actually basically use the raster to roster to polyline tool in order to actually convert this into into in into an stream network so I'm just going to use this input stream raster to be my stream order and over here I'm going to specify the flow Direction roster in this one I'm going to name as stream Network all right now we have a polyline network of streams I'm just going to turn off all these layers which we do not need right now and I actually have one catchment over here which is represented in purple color so what I'm going to do is I'm just going to actually isolate all the streams that are falling within this catchment just by doing a simple clip operation so I'm just going to type search click here and under the analysis tool you can find the click click tool and your input feature is now going to be the stream network and I'm going to click the stream network by my boundary of the catchment in this one I'm just going to name it as rivers all right so I can turn off this stream Network now and now you can see all the real you can see the river network which actually falls within my specified catchment so if I go to the attributes table of this rivers you can see one column called grid code now this grid code column is the column which contains the the order of the streams if I sort this from a toe is it which means from from the lower numbers to the higher numbers and if I highlight just the the grid codes with number four you can actually start seeing that this is my major river line so that's a pretty cool trick and one more thing that you can do is actually you can okay I'm going to deselect this you can go to categories over here and select grid code and click add values and I'm going to select the order with the distri m-- with the higher highest order probably going to specify that in blue color and I'm going to increase increase the thickness of the line to be 4 and this one I'm still going to leave actually the purple color I'm going to increase the thickness to be maybe let's say 2.5 this one I might change the color and I'll increase the thickness to be around 1.5 and lastly this one I'll change the color to 1 change the color to green and keep the width as 1 if I click OK if I remove the catchment you can now actually start seeing what are the streams of the highest order and what are the contributing tributaries and what up basically will the headwater streams which has the least number of order so I guess this was a pretty cool tutorial I hope you enjoyed if you did please click the like button and obviously share it with your friends and if you would like to see more cool J's tutorials like this you can even consider subscribing so thanks a lot for watching I'll see you in the next one bye

Channel: GeoDelta Labs

Views: 45,101

Rating: 4.9785175 out of 5

Keywords: stream order, strahler, derivation, how to, derive, a stream network, using, arcgis, arcmap, spatial, analyst

Id: NrBUd_cFXxc

Length: 14min 0sec (840 seconds)

Published: Sat Mar 23 2019