This feeling of ominous..ness.. seems to occur to all the viewers who have commented although it wasn't done intentionally. Maybe we all have an instinct that a kid near a river in a forest is naturally high risk 
In actuality sometimes a child will stop their play for a minute to just...bring it all in. They sort of stare blankly for a minute in pure wonder and awe, a sort of feeling that comes less and less as we grow older until the point that we need to purposefully seek it out...in this sense the intended emotion of this was a sense of nostalgia for when wonder came easily.
Yet it feels all the more authentic that, in a moment where the child may be experiencing wonder, we the adults feel a sense of dread that something may go wrong! That's really the essence of it, I suppose, the kid in the moment and us in our anxiety.... glad you love it.
I love how this piece is able to give this ominous feeling, there isn't anything strange to be seen yet it feels like something might go wrong.
Yeah, agreed! Makes a lot of sense, taking care of children is exausting and you must always be on the lookout of hidden dangers. On the other hand, I think the ominous feeling also comes from the shading, even without the kid I would probably still feel this. I get the same thing from your april fools submission