I feel, that despite all the effort the expert obviously went to;you were ill advised...the very first thing the expert should have advised you to do,was invest in 3/4 good books,1st book that will give you a "cheap taster" is A Japanese touch for your garden by Kiyoshi Seike/Masanobu Kudo, available from 1.95, the next one has a number of black and white photos but overall has good technical text and uses materials that are available in this country but DO NOT try to identify them using their Japanese names; this book is create your own Japanese Garden a practical guide by Motomi Oguchi, the last 2 books I recommend are both by the same author,Katsuhiko Mizuno,they are:-courtyard gardens of Kyoto's merchant houses and Landscapes for small spaces, 1 would probably do you, so go for the former; primarily just picture books, however they will show you just where I believe you have been ill advised, a small japanese courtyard garden, in the main,is called a tsuboniwa, a tsubo is a japanese measurement,roughly 9 and a half foot by 9 and a half foot (for the purists N.B. I am not giving exact instructions etc. only a generalised taster and very basic understanding) So you do not need any great or even Average space, some Japanese make do with a balcony!, As for physically needing water,you don't! the 3 elements in a japanese garden are rocks,plants and yes,water...however water can be portrayed using gravel or pebbles,plants can be as few as 2, one even being moss!!...and as for big rocks...why? it depends on the garden you choose, rocks can be the sand,gravel or pebbles, they are all rock...so my first advice is just sit and absorb the pictures and information in books, Japanese gardens are complex to get right, anyone can produce the disneyfied idiom of a japanese garden as detailed by the expert and as portrayed in the accompanying picture (I am sorry but it's true) but with a little research in the form of reading or if you are down that way, the Japanese garden in Newquay,Cornwall is one of britains least known about but probably the most authentic in "feel" Japanese Style gardens in the uk/europe, and expert, if you read this....may I advise the same reading, I have a Tsuboniwa garden that is 2 tsubos on one side of a formal "Nobedan" path and 1 and a half tsubos on the other, both slightly different in design but linked by the materials and planting, then I also have another small garden which is exactly a tsubo, but because of what it contains is NOT a tsuboniwa/courtyard garden, it is instead a tea garden and this is then, within a modern deciduous tree'd "Roji" (tea/small stroll style garden,Roji roughly means means dewy path and is my garden big..no!approx. 145 foot by 35 foot and there are 4 gardens within that space.
PS:MY LAST ADVICE IS SHOP,SHOP AND SHOP AROUND,USE THE INTERNET AND DON'T BE FRIGHTENED WHEN CONTACTING SPECIALIST COMPANYS TO ASK FOR A DISCOUNT OR TELL THEM OF ANOTHER COMPANY WHO IS DOING THE ITEM CHEAPER.
I hope this all helps you and others that view this item and you don't think I am an arrogant know-it-all,I have been studying and learning about Japanese Gardens for years...and I am still right at the beginning, still with "L" plates on but I just get annoyed, when experts...trot out, a 1 plan,1 design fits all "Japanese Garden"