You have no idea. That part was not well thought out. I didn't wanna get my work boots dirty. After all I'm an electrician. Not cut out for this manual labour. 😁
Yes it's a good idea. This was done on a budget and designed to last less than 10 years. I would advise building on concrete base to prolong life of sleepers. Depending on size sleepers stacked flat for more strength if larger pond.
Water Hawthorn, which is similar to lily. Plants at back are orange peel plant. At front water forget me not. Weeping willow next to pond and some ferns to cover filter water butt.