The garden was planned and designed by myself for our late "mums" with the top pond forming a "teardrop" [ although being upside down] to get flow from one to the other. The main pond was constructed oplong to give it size and balance. i shall upload photos later showing construction stages and fiter systems/pumps size so people planning ponds of there own get a feel as to what required, time and effort, ...= rewards. As im in my sunset years, i decided to build " UP " rather then down, reason! easy to stoop, and bend over, then on all fours or trying to get into pond to maintain it, slipping and landing on ones BUTT. next was to design and draw layout, once done get planning permission if needed . with this out of the way it all hands on and the fun starts. By building "up" you only need footing for brick/blockwork, if blockwork 100mm either side of block would be ok, making 100+225+100= 425/450 depending on block size. trench width now optained, depth needs to be 400/500mm and filled with concrete [6 ballast-1 cement] MAKE SURE ALL FOOTING ARE LEVEL---- EVEN IF THE GROUND SLOPES. then wait until concrete is dry and white in colour. Whilst waiting, other jobs to do, small stack of blocks around pond area, help once laying starts. ONCE DRY--- BUILD BLOCKS--- MAKING SURE LAST COURSE IS PREFECTLY LEVEL ACCROSS POND ALWAYS..easy way to check-- long lenght of clear plastic tubing, fill with water to height required, gives you a very long level.........more to follow.