I long ago abandoned all the huge hassle of pouring toxic resins and having to add drops of coloring in it to tint it…..way too much prep. and work for my tastes.
I learned about a decade ago how to create water and make it look like it actually looks in nature., and do it without trying to achieve depth with multiple layers of poured resin. First off you go through a ton of money buying enough resin to fill the channel to any depth. Second, you have to go through all the nonsense of sealing off the ends of the river channel, etc.
The color of your river is GREAT. In fact perfect I think!
Here's some photos showing my technique that I learned from other gamers on Youtube and tutorial sites:
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And here's some support photos I posted showing actual rivers in nature and how they look when light reflects off of them in the day time. You'll see that in all three cases the river actually looks like it's make of a dark BLUEISH or dark BLACKISH liquid. In most rivers in most places in the world, you cannot see the depth of the river when looking at it from any distance away.
Even when a river is only a few feet deep, it's surprising how opaque it looks. Only in the very rare, very cleanest and pristine waters can you see straight to the bottom. Therefore, when modelers try to make their rivers CLEAR by using resin, it's actually incorrect for most cases in nature:
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By FAR the best product out there for creating super realistic water effects is MOD PODGE. This stuff is a miracle product for wargamers and terrain makers! It is acrylic and water-cleanup, much like an acrylic gesso. It comes in matte and gloss.
The gloss stuff dries ABSOLUTELY clear and highly glossy. It's perfect for a water surface of a river or a lake.
All you have to do is have a flat baseboard of some kind to start with. In my case it's 1/2" MDF board. I then glued sheets of insulation foam to the top of it. I then carved down into the foam, utilizing the MDF layer as the actual surface of the water. That ensures that your water level is perfectly flat since the MDF is flat!
Then all I do is paint the MDF board a dark color like a bluish black or a brownish black. Then the Mod Podge is applied over the top of the paint. All you need is ONE application of it, dab it on back and forth like gesso. There is absolutely no need to pour resins to create depth. The illusion of depth is created BECAUSE of the gloss over the DARK color! There is also NO need to seal off the ends of the river channel because the Mod Podge layer is as thin as a layer of like white glue and it sets up so fast, it doesn't ooze out the channel like a resin would. Easy as could be!
If you are not familiar with Mod Podge, you can get it practically any where in box stores or craft stores, and it's a fraction of what resin water effects cost:
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Hope this helps! But as I said at the beginning of my post, I think your river looks perfect, you achieved the way it's supposed to look, even though it feels like an accident!