I suspect the purpose of the arches is to disperse boat wakes in the narrow channel which is the canal. This section of the canal is located between locks 2 and 3 of the Erie portion of the New York State Canal System in Waterford, New York.
All shots are three image +/- 1.5 EV HDR processed files made with a Canon EOS 5D Mark II and either the EF 24-70mm f/2.8L USM or the EF 70-200 f/2.8L USM lens. Exposure information in the captions is for the normally exposed image. Shutter speeds will vary appropriately for the other two exposures.
|200mm, f/5.6, 1/350 sec., ISO 400|
|110mm, f/5.6, 1/250 sec., ISO 400|
|32mm, f/11, 1/250 sec., ISO 400|