Creating a river and a bridge in blender seemed a little daunting at first, but I manage to create a river without using the fluid simulator simple by applying a cloud texture to a mesh plane. I attempted to model the bridge starting with a cube and the outcome is what you see above. For good artist blender is a great medium for expressing your creative endeavors and for beginners like me it is a perfect practice venue. Believe me I can use all the practice I can get.
I encourage you to play with blender as much as can, as the more you do the easier it gets. The more you tinker in blender the faster you learn your way around the interface. I will be working on some beginner tutorials soon to get you newbies up and running. The more I learn the more I will share.
Have fun in the 3d world.