If it was me, I would build it to look like a stream--side views would be limited to pools and a few riffs, but mostly have top viewing areas. Actually construct a stream bed, with twists and turns and some angle, with a sump. Then you could pile the edges with bog plants, and have nifty pools, etc. Think it would be cool, and you could have areas where the riffs were only 1-2 inches deep, providing lots of surface agitation, and some limited moving of fish from pool to pool.