Here is a decorative rainwater swale done by Samuel H. Williamson Assoc. that will give you a good idea of what your stream might look like in nature. I chose this picture because it represents a small space. The flat rocks do not fit in a stream bed. You would be better off adding some boulders and plants to bring your space to life. Remember that a small pooling area is needed near the end of your run. http://st.houzz.com/simgs/7ed1b4470f74a953_7-9389/contemporary-landscape.jpg

Is there an attachment that I am missing?

Sorry. I edited the above with the attachment.

It looks like just a bunch of rocks. Because, right now, it is. It desperately needs some foliage. Cram some grasses, perennials, and trailing ground cover into every nook and cranny. Look into a few bog plants and put them in the stream. It will make a huge difference!

Stick with the same stone the whole way thru to give it a more realistic look. Id also probably lose some stone and add plants. The space is pretty cramped right now so look at detracting stone to make it actually fit in the area instead of spill over into the concrete which is doesn't blend with very well at all.