Rushing water,colorful rocks can create a very nice composition.You must wait until very late in the evening for the lighting to warm up and bring out the color in the rocks. I have gotten exceptional results when the sun has disappeared below the horizon.In the photo I have placed rocks in the foreground  and framed the running water with rocks to give the photo depth. This photo was shot at 75mm with the settings of 4.0 sec @ f29. This allows for great depth of field.