The bridge is being built because of the determination of Rod and Wendy who live in a house looking out over the water - you can just see it in the picture - to find a way for them and others to get across the river to the center of the town.
They also wanted to find a way in which people in the town could enjoy the riverscape and countryside that exists the other side of their house but you wouldn't know about in the sea of penny shops and car parks in the town.
Curvy is the bridge. Straight forward the motive.
More on the project at