Is there any way to produce less channels?

[CR7zsc]

I created a 500*1000 grid. After evolving over thousands of years, almost 30 channels formed. But the more rivers there are, the easier it is to river capture. So I want tu focus on just about 5 rivers. Is there any way to control the number of rivers?

[gregtucker]

Is this for some type of landscape evolution model? If so, two points to keep in mind. First, simulated drainage width, at least initially, tends to depend on the initial slope (if any) given to the topography - steeper initial topography makes more closely spaced drainages. Second, there is a useful rule of thumb from Montgomery and Dietrich (1992) that the width of a "mature" drainage basin tends to be roughly 1/3 of its length. Of course, you can also make your grid narrower.

[nicgaspar]

If you are interested in river capture and drainage density, you might want to look at this paper: https://esurf.copernicus.org/articles/8/893/2020/

Nathan Lyons used Landlab to model river capture and found that as you said, drainage density impacts capture. You can see from his paper how to make more and less dynamic (with respect to river capture) landscapes.

[CR7zsc]

@nicgaspar @gregtucker Thanks for your reply. It's my fault that I didn't make myself clear. Lyons modeled the capture like one network captured by the upper network (If I understand that correctly). But actually I care about the river captured by one adjacent river because of strike-slip fault. If drainage density is too large, little strike slip could make capture happen so I want to find a way to produce less channels. Tucker's points are good but if the slope goes down, the rivers'll be more curved, which means that it's diffcult to produce some straight rivers with low drainage density. Maybe I need more time to test that. Thank you all again.