We moved in to our place a few months back. The previous owners had a small pond with no filtration and some unhealthy goldfish, we've since moved them to a larger pond and taken out the pre-fab pond that was in the ground. The space left is adjacent to the deck. My primary job is to raise this "pond area" up to the level of the deck and probably add decking to it (this latter part is not essential - see below).
My main question is - what do folk recommend for filling in the space? My dad suggested gravel, but I wondered about cost and subsidence - is there a better option? The ground is compacted soil and the space is 150 (w) x 100 (l) x 30 (d) cm. See attached photos (it is currently hosting some plants we need to keep away from the puppy - apologies if that obscures the view somewhat).
The puppy leads me to my next question. I want to install a dog door in the leftmost panel of slats so the puppy can come in and out. The area I am filling in is therefore primarily for his use and doesn't need to be decking - any thoughts on cost-effective alternatives would be appreciated.
Many thanks for any replies,
James