Peter. the only fishing voilation (or any violation of any kind) I ever got in my life was becuase of the confusion regarding that exact rule. I even tried to fight it in court. Apparently you need to read the alberta fisheries act ... it's available online at the AB gov't website... Turns out fishing anywhere near any structure of any type (wier, spillway, etc) is illegal. I guess all the folks fishing the inlet at crawling valley for walleye better move eh? They can give you a ticket for fishing ANYWHERE within 25metres of ANY obsatcle, if the CO is having a slow day and feeling like being a dick instead of actually going out and getting poachers.