That is so frustrating, I'm sorry that happened. My old leash broke once while my dog was chasing a squirrel and I had to chase him for like three blocks. At least it happened close to home and not a mile away. Hope your dog didn't get loose when it snapped. That handle in the storm drain is just adding insult to injury.
Idk, I feel like the storm drain part is way worse than the leash snapping lol. At least a broken leash is just a thing that happens, but losing your handle down a drain? That's just the universe being mean for no reason.