Arctic Watershed- 02/19/22

This week in lab we explored hydrology tools in order to delineate a watershed from data retrieved from USGS

Lab Objectives

• Collect 10 m DEM of objective sites and derive info to delineate a watershed

After locating a river site that could be constrained within a basin or canyon type land features I secured DEM data. From this I was able to run multiple tools that helped pull information from the topography to understand where water goes when it falls and where it will accumulate(i.e. rivers). First running a flow direction tool which resembles an aspect map, I was able to corroborate this by comparing to the DEM with a hillshade layer to inform where topographic features were. Then proceeding to run an accumulation tool and delineate a watershed from a pour point. Flow accumulation takes into account flow direction and can create a raster set that creates values for the cells based on a count of cells that would drain to that cell; where flow direction was converging lines would being to show on the map.

• Clip Flow accumulation and define stream order

By generating a binary dataset from the flow accumulation I could define at what point a stream would show up depending on how many cells collect in another cell. I created a transparent layer and set the basemap as a USGS topographic which has mapped rivers and I could adjust the threshold in order to have my watershed accurately represented. Lastly, delineating stream order based on the threshold I established. Because I defined what flow accumulation designated a stream and what did not I could use use a stream order tool to calculate what order the each tributary was based on how many streams were conjoining.

• https://drive.google.com/file/d/1NlVWfhhUH9Vtm87XoptjJlx9UhpPGTWA/view?usp=sharing