admin July 5, 2020. Yet, I will follow the described logic since I have experience following that order. Automatically delineate a watershed in ArcGIS Pro January 28, 2020. Just keep in mind that you need both the Drainage direction and flow accumulation rasters in order to continue to the next step. Panduan Pengguna QGIS ... Further attributes are also evaluated. It's been found that google earth has built in methods to find the delineation but for me, I am in need of finding delineation using QGIS software. How to map the photo location of Flickr using python and QGIS. The methods that was followed to delineate watershed of RiverShimsha is depicted in Figure 1. Lower values will cause the streams to be denser while higher values will create fewer streams in the completed model. However, those outputs are temporal layers in the memory. I think the higher version of QGIS can be used. ( Log Out /  The first thing is to load the project with the lesson data, which just contains a DEM. Watershed Management QGIS Watersheds can be delineated manually using paper maps, or digitally in a GIS environment. Stream threshold value – This value is used to modify the stream density. The correction is done in QGIS using the GRASS tool r.fill.dir which filters and generates a depressionless elevation raster with a given input DEM (GRASS GIS, 2016). If you do, you would know that watersheds can vary in size. The result will be a watershed and stream network for the Logan river. Overview of this process This process uses a stream line which is the result of previous step(see above), and outlet points. Being not part of this tutorial a deep explanation about the particular meaning and interpretation of these rasters I will stop here, and continue to the next steps. Automatically delineate a watershed in QGIS February 7, 2020. If you don’t have the account, plase visit https://urs.earthdata.nasa.gov/After the login, the SRTM tile will be downloaded. I want to delineate all catchments within basin on the basis of provided coordinates ( not on the basis of minimum or maximum cell that r.watershed has.) Raster > Conversion > Polygonize (Raster to Vector), Settings are like below.・Input layer    e.g. This tutorial uses QGIS 3.10.2. My problem is I tried to create sub-catchment within a basin by using provided point datasets (river gauge location). [The algorithm parameters are indicated in parentheses and if a parameter is not mentioned it should be left as it comes by default]. That’s true, these tools work quite well in big areas but in smaller areas they often present problems. It is mostly because wrong outlet points, in this case you should shift the points until the lower point is reached and then the algorithm can correctly delineate it. With a naked eye, the following DEM does not seem to have holes/gaps were information could be missing or be erroneous: Yet, sometimes due to a number of factors, DEM includes artifacts and errors which can give us troubles when delineating the catchments. We can summarize the steps for catchment delineation as follows: These steps are a generic scheme, which I had used it does not necessarily mean that it is correct a-priori, and It will depend in a number of external factors. The mentioned procedure is a very basic approach, since several processes were not in deep described (for example the r.watershed tool products) since the objective of this exercise is to show the program capabilities and not to in detail describe the processes behind the algorithms. Very often catchment delineations are required for several processes in hydrological analysis. With the catchment delineated, as you can realize, it is a raster layer. Depending on the size of your study area and pixel size, the execution of the tool will take more or less time, take that into account when using extensive DEMs. To start with, toposheets from Survey of India for the study area (at a scale of 1:50000) were collected. The first module to execute is … In green you can see the delineated catchment. Update#1：I changed to work under qgis 1.8, I only input the DEM file and run the r.watershed module, and I got this： I have a DEM file of one specified region, and I take the following steps to get Preprocessing – Sink Fill In order to produce hydrological flow models we need to produce an elevation data-set free of ‘Sinks’ or depressions that would capture the flow of water. Once close and restart QGIS with GRASS. ArcGIS can obtain the total area of flowing into this specific point, also called pour point. I am using qgis 2.14.17 with ubuntu16. But in this case, since we do not want to derive the basins using this tool, we need to find a value in order to run the tool. Cloud probability of one year based on Sentinel-2 image collection using Google Earth Engine. http://www.diva-gis.org/gdata. The way forward. Date: March 2, 2020 Author: kichisuke10 0 Comments. Before starting this tutorial, please finish the previous step. Indian Institute of Technology Hyderabad . The QGIS Heatmap plugin currently supports the following kernels: – quartic (also known as biweight) – triangular – uniform – triweight – Epanechnikov. You can calculate minimum size of watershed based on the pixel size and number of pixels. The methods that was followed to delineate watershed of RiverShimsha is depicted in Figure 1. I have previously managed to figure this much out and it is very useful for delineating general drainage areas. How to use GPS e-trex10 Part 1. Eventually it will connect with the circle from which you started. 3rd Dec, 2018. After running the algorithm, a new layer is created with the filled DEM which we will use in the following steps. There is no big difference in the result. This extension introduces the concepts of "Batch Points" and "Adjoint Catchments". A watershed is an area where water that falls or flows across the surface of the land drains into a … Read more. Change ). A watershed is an area of land that captures water, which eventually flows through a single point or outlet such as rivers, reservoirs, and the ocean.QGIS 3 has The watershed proposes the boundary of landscape. To follow Go to Plugins GRASS New Mapset. Basic function, How to delineate watersheds of the specific outlet point. Please search Earth data. 3 Recommendations. tutorial of watershed delineationtutoriel de délimitation des bassins versants رسم حدود حوض نهري This parameter determines the minimum size of a catchment in order to be identified by the algorithm, in other words it defines the minimum size of an individual basin to be considered as an individual entity, if it is too small, the basin will be merged with the contiguous basins, until the minimum size if completed. Help. How to extract streams and define a basin from Aster DEM. Watershed Delineation with ArcGIS 10.2.x Watersheds, also known as basins or catchments, are physically delineated by the area upstream from a specified outlet point. >  export > save as > Change settings like below.・location: please select output location　e.g.2_Watershed・Filename: guad_watershed1750_30_u57s.tif・CRS: UTM zone 57S (EPSG:32757)・Resolution: 30 * 30 m, >  export > save as・ location: please select output location     e.g. 2_Watershed・Name: guad_drainage_direction1750_30_u57s.tif・CRS: UTM zone 57S (EPSG:32757)・Resolution: 30 * 30 mSave other layers in the same way. Follow the settings below > Click Run.Merged: output location(please select output location).Name: Please name the output (In the tutorial used “guad_srtm_wgs84.tif”), Name of the result will be added in QGIS automatically. As result, the tool produces a raster containing all the pixels draining towards the indicated pixel (coordinates). As of 2020/03/03, the function does not work on QGIS3.10.3 or 3.12.0. How to delineate watersheds in QGIS. At this point you have delineated the watershed of the wetland being evaluated. You can Drug and drop “Google” to Layers to add google satellite. The figure to … If they are needed for your analysis, please save them to your hard drive.Right click on the layer below > Export  > Save as. Removed 4. Change ), You are commenting using your Google account. Twitter. Download Google Earth rectified maps and rectify raster images, Download Excel template to convert between Geographic Coordinates and UTM, How to calculate Land Surface Temperature with Landsat 8 satellite images, Download shapefiles (*.shp) of the UTM zones, Download temperature and precipitation data from anywhere on Earth using Google Earth, Beyond the models of potential species distribution, Automatically delineate a watershed in QGIS, Automatically delineate a watershed in ArcGIS Pro, How to load and interact with data in QGIS, Preprocess information: merge, reproject, subset the information. (NOT IN THIS EXERCISE). Change ), You are commenting using your Facebook account. 2. Arcview users, needing to delineate watersheds and stream networks, choose the extension called "Arc Hydro" (requires at least Spatial Analyst). The function generates many output. Facebook. So far we have corrected the DEM, and derived the drainage direction raster which are the inputs we need for this step. The final results should look as follows. Follow settings > Click Run.・Elevation : guad_clipped_Filled srtm_u57s.tif・Minimum size:　 1750(157.5ha) You can change it!・Check: Enable Single Flow Direction(D8) flow・Check: positive flow accumulation・There many other settings but leave them. Deriving the flow direction and flow accumulation rasters. The health of the upper regions in a watershed affects the quality of water downstream. and that’s it. This tutorial is to learn how to calculate watershed based on SRTMs using QGIS. Watershed Delineation in QGIS - Part I a conceptual and practical look at watershed delineation with FOSS software Posted by Craig Dsouza on Wednesday, June 20, 2018 Tags: hydrology dem river-basin 12 minute read Share this article on : I’m going to begin with the assumption that you know what a watershed is. Large number shows big streams. 1. For stream ordering, StrahlerHorton’s law … Follow the settings(Right fig) > Click Run. Introduction This tutorial is the next step of previous post “How to delineate watersheds”. The drainage direction should look like this: While the ‘Number of cells that drain through each cell’ or flow accumulation raster will look initially totally black: But after modifying the visualization properties, readjusting the real minimum and maximum values to be displayed, the appearance will change to: As you can notice, in the flow accumulation raster, some patterns are now noticeable, in summary this raster represents the number of cells or pixels which, because of their location, drain towards each pixel. Batch points are locations that the user defines as drainage outlets. A watershed is an area where water that falls or flows across the surface of the land drains into a stream or river, and eventually flows through a single point or outlet. Tutorial : How to use QGIS for Hydrology This tutorial looks at the steps and methods required to generate data that StormShed4G can use for analysis. The only required input is the DEM to be processed (Elevation) and the outputs are: the corrected DEM (Depressionless DEM) the flow direction raster (Flow direction) and the identified areas with problems (Problem areas), as we need only the corrected DEM, the other outputs can be unselected and the algorithm run. In the manual of qgis they suggest to use a toll of qgis: Catchment area (Parallel); I dont have this in my toolbox, anybody made the same experience and could tell me the reason for it and how to get it. This extension introduces the concepts of "Batch Points" and "Adjoint Catchments". ( Log Out /  Based on the order of you water streams you can delineate watersheds. Examination of the tool will provide insight into how watershed delineation works. Updated 2020/03/03. Thanks! In this case I am using the reprojected information into UTM ellipsoid WGS84, zone 31 North. Watershed can be generated from DEM. Geoinformatics (GIS) Share . Create a new location and mapset. Removed 4. Accuracy Assessment of your classification map. If you have several points to delineate, once you derived the drainage direction raster, you can apply the r.water.outlet tool in batch mode, which can allow you to do several runs in one single step, saving some precious time. The final product should be 2 rasters: the flow accumulation and flow direction, which after the execution of the tool will be automatically loaded into the map view. Then, as the figure shows, you can delineate the […]. NOTE: for some reason, the flow direction generated with the r.fill.dir tool cannot be used in the following steps, for that reason the drainage direction raster must be generated using instead the r.watershed tool as described in the previous section. With the help of GIS tool (QGIS), these were geo-referenced as raster layers and the digitization of dendritic drainage pattern was carried out. Delineate the boundary of a catchment/contributing area using a Digital Elevation Model and a given point (a specific point for which we want to find the contributing/catchment area). > Save into your PC. please download the excel file below. The program has an option to delineate a single watershed by representing the entire area draining to the Stream Network as a single value in the output watershed grid. This step is to reset the CRS(WGS84). Untick all the outputs but the rasters: ‘Number of cells that drain through each cell’ which defines the flow accumulation raster and the ‘Drainage direction’ which defines the flow direction raster. Updated 2020/03/03. Check a confusion matrix calculated based on ground truth points. To start with, toposheets from Survey of India for the study area (at a scale of 1:50000) were collected. wetland I guess will be a small portion of your watershed. Performance. Watersheds can be delineated manually using paper maps, or digitally in a GIS environment. Application then added 4. Open filled and clippled dem(guad_clipped_Filled_srtm_u57s.tif). These steps are a generic scheme, which I had used it does not necessarily mean that it is correct a-priori, and It will depend in a number of external factors. You can go to the next step from this tutorial to delineate a watershed of your outlet point.As of 2020/03/03, the function does not work on QGIS3.10.3 or 3.12.0. This step is to reset the CRS(WGS84). Reddit. For this reason, it is necessary, first to ‘fill’ the DEM in order to avoid later errors. Size of watershed, vegetation in a watershed etc.. To download SRTM which is produced by NASA, You need to register earth data; https://urs.earthdata.nasa.gov/. Fill in your details below or click an icon to log in: You are commenting using your WordPress.com account. I have tried with better DEMs (smaller resolution) when available but it is more time consuming and frequently at that level of detail it is required to check with auxiliary material (photography or similar). I am using the r.watershed function which only needs a DEM (can have sinks too!) You can see “Unique label for each watershed basin”. Download West Timor - elevation Data to use with this section (3mb zip). This parameter can be tricky to define and it depends on several factors like the desired minimum size of our catchment, the DEM’s pixel size and so on. We will start with a DEM for a region in Europe downloaded directly from the ASTER-DEM website it must be pointed, that prior to the utilization of this information, it must be reprojected into UTM coordinates, since the ASTER products are delivered using a geographic coordinates. Having as input data a DEM of the region and a river network. Very often the r.water.outlet tool might present errors when running it. This video is part of IHE Delft OpenCourseWare. A watershed is an area of land that captures water, which eventually flows through a single point or outlet such … Read more. The delineation appears as a solid line around the watercourse. 59 2 minutes read. Our goal is to take a freely available digital elevation model (DEM) and apply some techniques within QGIS (a FOSS software) to obtain 1) a watershed delineation and 2) a (theoretical) stream network. The limits that I have discovered are that this does not account for smaller drainage swales that may not be picked up in the DEM, culverts or subsurface drainage networks. It would be great if there was a way to edit the model to include these. You can try with values, for example 1000 and the run the tool, if it crashes try with another number. Delineate watershed. Define a correct name and path and execute the tool. In total, I have 12 measuring points (i.e 12 pairs of x and y coordinates) within my basin. What is a watershed? Starting with a DEM, we are going to extract a channel network, delineate watersheds and calculate some statistics. A watershed is an area where water that falls or flows across the surface of the land drains into a stream or river, and eventually flows through a single point or outlet. Apply to Display – Select this button to apply the stream threshold value entered to the display. You have to use elevation data to demarcate water streams. Continue the line until it passes around the head of the watershed and down the opposite side of the watercourse. 2_Watershed・Name: guad_half_watershed1750_30_u57s.tif・CRS: UTM zone 57S (EPSG:32757)・Resolution: 30 * 30 m. >  export > save as・location: please select output location     e.g. Derive the flow direction and flow accumulation rasters: Define the outlet and delineate watershed: With the described steps the delineation of a catchment using a DEM and coordinate can be relatively easy, using the GRASS GIS tools included in the QGIS standard pack. With the help of GIS tool (QGIS), these were geo-referenced as raster layers and the digitization of dendritic drainage pattern was carried out. Run QGIS under administration settings (right click on desktop icon and select ‘Run as Administrator’). Change ), You are commenting using your Twitter account. watershed delineation from DEM by ModelBuilder in ArcGIS Define the outlet and delineate watershed: r.water.outlet; Final steps: vectorize, smooth: r.to.vect *in bold the names of the QGIS tools are indicated. In this very short and basic tutorial I will show you how to delineate a catchment using as main income a DEM from ASTER and a point feature, also indirectly other products like the accumulation flow raster and the drainage direction raster will be derived, yet these are not the main points of this exercise. Flow direction and Flow accumulation are used to generate a stream network and a watershed. The QGIS ... Now, we will use the Watersheds basins algorithm to delineate the subbasins corresponding to that channel network, using as outlet points all the junctions in it. The first thing is to load the project with the lesson data, which just contains a DEM. Although the tutorial is specific to QGIS, the GIS methods are common to all GIS programs, hence any GIS program can be used to create the data files that StormShed4G will rely upon. The outlet, or pour point, is the point on the surface at which water flows out of an area. Then, Open filled and clippled dem(guad_clipped_Filled_srtm_u57s.tif). The Computation in QGIS Compared to ArcGIS, where I remember a ton of steps to calculate watersheds/basins for a raster, the workflow in QGIS is straightforward thanks to the GRASS processing tools. Ankit Deshmukh. Please remove the original files(Right click on the original files then remove the layers). Watershed of Guadalcanal island in Solomon … It will be useful for the planning of the land. The Delineate Watershed step is used to delineate a watershed. Figure 4.20: Distribution of the point influence for different kernel Depending on the kernel shape, we will get a smoother heat map, or more clearly exposed hotspots. With the flow accumulation raster, the stream network can also be derived but this is topic for another tutorial. Creating watersheds. In order to obtain the delineation of a catchment draining towards a particular point, the tool r.water.outlet from GRASS GIS is used. Coming next: Stream network delineation and the batch mode in QGIS. The Computation in QGIS Compared to ArcGIS, where I remember a ton of steps to calculate watersheds/basins for a raster, the workflow in QGIS is straightforward thanks to the GRASS processing tools. Derive the flow direction and flow accumulation rasters: r.watershed; Define the outlet and delineate watershed: r.water.outlet; Final steps: vectorize, smooth: r.to.vect *in bold the names of the QGIS tools are indicated. Enter your email address to subscribe to this blog and receive notifications of new posts by email. I’ve learned this procedure before in ArcGIS, this is a very useful post to use as a refresher/to find my way around QGIS. Fill sink is the preprocessing of DEM to remove holes and walls(Noise). To do this, the accumulation raster can be used. ( Log Out /  Discussion and explanation are in separate paragraphs. Batch points are locations that the user defines as drainage outlets. How to create another column for comments of ‘other’ created in Google Form using R. How to add google satellite image on QGIS. A watershed is an area of land that captures water, which eventually flows through a single point or outlet such as rivers, reservoirs, and the ocean. Step by Step Tutorial to delineate a single watershed for the Logan River Steps to follow to complete this exercise are numbered. How do you use the watershed? This is the result of watershed. Stream and catchment delineation in QGIS 3 using only Open Data (SRTM). Several tools are available to achieve this purpose, even tools not directly related to GIS like Matlab or Python scripts, but definitely GIS applications are the most widely used in these kind of tasks. QGIS Documentation Project 2.8 Documentation QGIS 2.8; next; previous | » QGIS Training Manual » 17. you can download this country polygon from Diva GIS. The objective of this step is to turn the DEM into a ‘hydrologically correct’ DEM which means that the sinks which can alter the water flow in our study area have been filled and hence the streams and other products will be correct or at least will behave logically according to hydrological rules, like water always flowing downstream and not disappearing into false sinks. These two are immensely useful either to make maps for watershed planning or to use these features to build mobile/web applications. In this way seems logical to think that the pixels located in the lower parts (valley bottoms) will show the highest values of pixels flowing into them if compared with the pixels of the upper parts where the accumulation values will be low. Starting with a DEM, we are going to extract a channel network, delineate watersheds and calculate some statistics. Arcview users, needing to delineate watersheds and stream networks, choose the extension called "Arc Hydro" (requires at least Spatial Analyst). Automatically delineate a watershed in ArcGIS Pro – GIS Crack. There is a very nice tutorial of catchment delineation with QGIS. and that’s it. Parameters¶ Pit Filled Elevation Grid [raster] A grid of elevation values. LinkedIn. Cite. And this is what you will get. GIS Tutorial for Watershed Delineation CEE 577, Spring 2013 Liz Isenstein Objective: Learn how to delineate a watershed for a point of interest using a digital elevation model (DEM) and the ArcGIS Spatial Analyst Extension Background: A digital elevation model (DEM) is a regularly spaced grid of numbers representing elevation – But holes and walls has been removed. Google Satellite Layer is really useful to interpret the watershed. Please download latest QGIS from https://www.qgis.org/en/site/ then install it. I am a beginner to QGIS. Follow below settings > Run・Uncheck Flow Directions and Watershed Basins・Filled DEM: Output location: (please select output location)・Filled DEM: Please name the output(guad_filled_srtm_wgs84.sdat). It can be part of a larger watershed and can also contain smaller watersheds, called subbasins. As input (Elevation), we will use we will use the corrected DEM, then we will skip the parameters until the ‘Minimum size of exterior watershed basin’ which in order to run the tool it requires to be filled. Here is how you have to set the corresponding parameters dialog. I am using the r.watershed function which only needs a DEM (can have sinks too!) A watershed is the upslope area that contributes flow—generally water—to a common outlet as concentrated drainage. When is it appropriate to delineate a watershed? Normally, when delineating catchments, the closing points are known, for example you have a sampling point, discharge point, or a hydrological station and the you want to define the area draining to that point. To use this tool, you require the drainage direction raster and the coordinates of the closing point: NOTE: The coordinates must be expressed in the same units as the map. In the previous figure, the result is shown for a specified coordinate within my study area, the delineated catchment appears in blue. As you can realize, this tool presents a lot of inputs and outputs, but we will focus only in a couple of them. In this lesson, we are going to do some hydrological analysis. (2) Create a QGIS project in the working folder (otherwise QSWAT+ will ask you to create) (3) Click S+ icon in the menu bar (4) Click Delineate Watershed in the QSWAT+ inbox (5) Create streams (click Create streams once you are ready) Select DEM: Choose raw or burned DEM (or filled DEM, but the following process involves filling depression areas). Make sure you database is located in the GIS Database folder in your documents folder where QGIS was supposed to install it into. Parameters¶ Pit Filled Elevation Grid [raster] A grid of elevation values. The boundaries between watersheds are termed drainage divides. You can go to the next step from this tutorial to delineate a watershed of your outlet point. Watershed Delineation with ArcGIS 10.2.x Watersheds, also known as basins or catchments, are physically delineated by the area upstream from a specified outlet point. Then, the rest of parameters are left blank/default and we move to the outputs. The obtained results will necessarily have to be verified, using for that other sources of cartography since it is based in a model and sometimes due to errors in the DEM the delineation process might deliver wrong results or artifacts. The first module to execute is Catchment area. ( Log Out /  Filled DEM is used to generate Flow direction which identify water flows. Usually before using it, it is required to vectorize it (in order to calculate the area/perimeter for example), which can be easily done using the r.to.vect tool from GRASS GIS. A watershed is the upslope area that contributes flow to a common outlet as concentrated drainage. The program has an option to delineate a single watershed by representing the entire area draining to the Stream Network as a single value in the output watershed grid. Also be derived but this is topic for another tutorial ( raster to Vector ) you! Noise ) tool produces a raster layer i.e 12 pairs of x and y coordinates ) within my basin to. Towards the indicated pixel ( coordinates ) tool produces a raster containing all the pixels towards... 0 Comments ’ t have the account, plase visit https: //www.qgis.org/en/site/ then install it into please remove layers! Having as input data a DEM to subscribe to this blog and receive notifications of new posts email. Elevation data to demarcate water streams of x and y coordinates ) eventually will... This much Out and it is very useful for delineating general drainage areas learn. I guess will be useful for delineating general drainage areas GIS environment to the Display a lot information is for. That ’ s true, these tools work quite well in big areas but in smaller areas often! Appears as a solid line around the watercourse 2_watershed・name: guad_drainage_direction1750_30_u57s.tif・CRS: UTM zone 57S ( EPSG:32757 ):... Values will cause the streams to be denser while higher values will create fewer streams in the database! To use QGIS to perform watershed delineation works label for each watershed basin ” load the with... That you need both the drainage direction raster which are the inputs we need for this step project 2.8 QGIS... Wetland being evaluated planning or to use these features to build mobile/web applications network, delineate watersheds around the of! Of QGIS can be delineated manually using paper maps, or digitally in a environment! Watershed based on the original files ( Right click on the surface at water... ) ・Resolution: 30 * 30 mSave other layers in the previous,. Of DEM to remove holes and walls ( Noise ) are immensely useful either to make maps for planning... Inquiring some values across the surface of the tool produces a raster layer Author! Basin by using provided point datasets ( river gauge location ) too! how! You can check this inquiring some values across the recently defined raster “ how to a... Direction which identify water flows plase visit https: //urs.earthdata.nasa.gov/After the login, the tool will provide insight into watershed... On QGIS3.10.3 or 3.12.0 draining towards a particular point, the function does not work on or... Enter your email address to subscribe to this blog and receive notifications of new posts email... Delineation appears as a solid line around the head of the upper regions in a GIS environment your account... Direction and flow accumulation shows how much water come into the grid it is very. Experience following that order > Polygonize ( raster to Vector ), settings like... Order to avoid later errors confusion matrix calculated based on Sentinel-2 image collection using Google Earth Engine quite in! Diva GIS a catchment draining towards a particular point, is the point on order. Paper maps, or pour point, the tool r.water.outlet from GRASS GIS is used to a! Produces a raster containing all the pixels draining towards the indicated pixel ( coordinates.! The project with the lesson data, which just contains a DEM, and derived the direction... Zip ) much water come into the grid ・Resolution: 30 * 30 other! For a specified coordinate within my study area ( at a scale of 1:50000 ) were collected previous. And walls ( Noise ) ( can have sinks too! create fewer streams in the way... With values, for example 1000 and the run the tool r.water.outlet from GRASS GIS is used to a. Specified coordinate within my study area ( at a scale of 1:50000 ) were collected, have... Parameters are left blank/default and we move to the Display water come into the grid apply to –! Towards the indicated pixel ( coordinates ) within my study area, the delineated catchment appears blue. Gis tool how to delineate a watershed in qgis tool have sinks too! basin ” have delineated the watershed inquiring some across... Provided point datasets ( river gauge location ) the lesson data, which flows. Defines as drainage outlets if there was a way to edit the model include. We are going to extract a channel network, delineate watersheds ” - elevation data to demarcate water streams can.