Perhaps your best work yet, Chris. This is wonderful! I love the geometry of the irregular sweeping curve. There is also a conceptual difference between the dark water and the bright grass. The clouds/jet trails reflection just adds an additional dynamism.
Is there, perhaps, just a smidgen more along the top? I understand why you don't want any sky or anything else, as that would ruin the felling of the sweep of river and grasses, but I think it needs just a bit more of the grasses along the top to allow the top left lit grass to "breathe" a little.
Also, consider accentuating the light by introducing just a little more local contrast and perhaps a slight warming to the lit grass areas in the top left and central "island" grass to give it slightly more visual and conceptual "separation" from the "cold" water.
Any thoughts on B&W - huge potential here, too. It is reminiscent of the great images made of the Snake River Canyon - the smaller scale here in no way alters the potential for using that beautiful light to its advantage.
Of course, if what I'm suggesting is completely out of line with your original intention, ignore me!