Complex sentence: As the canal would now not reach its proposed main source of water northwest of Wrexham, a feeder was constructed along the side of the Dee valley to Horseshoe Falls at Llantisilio; this narrow feeder branch was made navigable, allowing boats to reach Llangollen and beyond.
Split into simpler sentences: As the canal would now not reach its proposed main source of water northwest of Wrexham, a feeder was constructed along the side of the Dee valley to Horseshoe Falls at Llantisilio. This narrow feeder branch was made navigable, allowing boats to reach Llangollen and beyond.