Very much in progress might not work on main, still learning Unity.
Based on resources provided by the excellent youtube channel https://www.youtube.com/c/SebastianLague.
This code includes the code from his series on procedural terrain generation and also the code used for hydralic erosion. I've made some tweaks to it and made changes to have it working in URP with latest LTS of Unity ( 2020.3.1 as of writing this. ).