Frequency of Rivers?

[Pananacakes]

My map has a mountainous island that's relatively steeply sloped from its center down to it coast. It's ~720 miles long and it's width varies but averages, I'm guessing, 90 miles. I think a close analogy from it to a real world place would be Honshu since it's roughly the same size and is at around the same latitude. Honshu if Honshu was rotated 30 degrees clockwise. I'll say the climate and weather are similar too.

Because of its scale my map can only show features of 88 feet wide or greater (1 pixel = 88 feet).

Its rivers would mostly be small and fast flowing. But I'm not sure how small is "small." I only want to display rivers that are at least 88 feet wide. That is, once they reach that size they stay at least 88 feet wide til they reach the ocean. My question is how many rivers that big should there be? How many miles along the coast should separate them?

A quick look at Google maps of my local region seemed to showed rivers being pretty frequent but it wasn't always possible to tell how wide they were. I tried looking at Honshu on Google Earth but Earth is buggy on my computer and I can't get a clear enough close-up view to estimate river width.

[waldronate]

It's hard to draw rivers that are a specific size because most rivers vary in width from season to season and are likely to have vegetation along the sides that may drastically reduce the overhead appearance of the river. Mapping is about abstraction and you need to pick a useful abstraction for your map when you decide what to put onto it.

How many rivers should be on the map will depend as much on the geography of the land and its proximity to other areas as to its latitude. Consider that Sakhalin island and England are at very roughly the same latitude, but on different sides of Eurasia and have different topographies (different shapes, too). Their river networks are very different, with England having many rivers over 88 feet wide and Sakhalin having very few.

How far apart they would be on the coast is mostly a matter of the topography (to pick on Sakhalin again, it has a coast mountain range on each side of a central valley and its only significant river flows down that valley to an end of an otherwise long and skinny island).

There are quite a few maps of river networks of the world that might be instructive.

[Pananacakes]

I hadn't thought about that seasonal variation. It's a good point, and so are your others. Thanks Waldronate, it helps.