I've whetted my appetite for a splashy garden

In our backyard the ground slopes away from the house. This landfall, I realized when I started to remake our walled-in garden 23 years back, offers an ideal setting for a homemade stream. Running water in a garden! It's the finishing touch.

As a boy, I'd once attempted to make something like this on a very small scale. This time, I decided, it could be more ambitious - and wouldn't just be fed by periodically turning on a tap, as my earlier effort had been.

There is no natural spring here. So I knew we would need a good strong pump to circulate the water. This would be submerged in the lowest pond, and the "stream" would, we agreed, follow a curved meander through the garden and end up near, but below, the first, uppermost pond. The pump would have to push the water through an underground pipe only about 10 feet long up a bank ... and an overflow of agitated water would rush merrily over a small precipice and gurgle and bubble its way round and round. I could see it all.

When we drive up into the hills north of the city, we sometimes pass natural streams streaking down mossy hillsides, glassing over giant boulders, unpredictably changing direction, sweeping along then suddenly falling. I always look out for one in particular. "That's what I'm aiming at," I think, realizing how far short of nature's easy dialogue between water and moss and rock my own little artificial contrivances are likely to be.

Back at home, in our small garden, I (years ago now) dug a succession of holes. This done, I had to decide whether to put linings in them or to use good old fashioned concrete, which is hefty work, but can look more natural. I wavered. I have wavered now for about 18 years.

I was also waylaid by more pressing matters: making a study for my spouse, installing wood paneling, erecting bookshelves. And then the ducks were in great need of a fox-proof pen, and then, and then...

The "thens" proliferated, and still do. The "stream" has hung fire, if that's not a contradiction in terms. There is water only in its top pond (held in with a liner), and the rest is a neglected ditch. You could call it unfinished business.

But hope, they say, springs eternal.

We have, meanwhile, bought some massive flat slabs of stone. They are waiting to be placed as foot bridges over the stream - once we have a stream. We bought a pump reputedly fierce enough for a decent water flow. This seems to have taken up permanent residence in its box in the garage. Pipes and conduits are buried at the ready, though so far they contain neither water nor electricity.

But my interest in this long neglected project has been reawakened, in a totally unexpected way, by a new book by the garden historian Penelope Hobhouse. Unexpected because this is not yet another book on traditional British gardens. It is called "Gardens of Persia" and it traces the origin of the idea of gardens back to its roots. (See below.)

Persian gardens were called paradises. They were walled in. They were oases in a landscape of stony deserts. Water was often piped in at enormous expense for many miles so that a garden could exist. Thus, water, almost more than trees and plants, was the central meaning of a Persian garden.

Although Western travelers, and plant collectors, were fascinated by the gardens of Persia (modern-day Iran), Ms. Hobhouse points out that even as late as the 17th century, when the West had a "new enthusiasm for the exotic in gardens," Europeans were not inspired to reproduce walled Persian gardens. She suggests that a reason for this was the feeling that "the Persian garden needed a desert setting."

Scotland, I have to say, isn't big on deserts. We err on the side of wet, not parched. Nevertheless, reading this intriguing book, I have realized yet again the extraordinary appeal of water - still or running - as an integral part of a garden.

The Persian preference for rectilinear sheets of reflecting water, for formal fountains and cascades, is never going to be my taste. I'm after a little Yorkshire "beck" or a wee Scottish "burn." But I begin to feel it's high timeto get those ditches of ours filled up and set them flowing, dancing, rippling, and cascading.

The primitive idea of a garden was that it should be an enclosed paradise, an oasis in an otherwise arid world of desert. The oldest extant garden layout that can still be read - at Pasargadae in Iran (Persia) - belongs to the time of Cyrus the Great. who reigned from 558 to 528 BC.

Garden historian Penelope Hobhouse, in her highly readable new book "Gardens of Persia" (Kales Press. $49.95), writes: "Incorporating both architecture and planting, water rills and shade-giving pavilions, Cyrus's garden seems to offer the background to all later garden developments." She adds: "Watercourses formed the principal axis and secondary axes of the main garden at Pasargadae."

Indeed, the ancient Persians built elaborate underground aqueducts to carry water from melted mountain snow to the plains. Channels, canals, rills, and basins, integral to garden design, were from the start both practical and decorative.

After the Arab invasion of Persia in the 7th century, Islam adopted the Persian paradise garden as a symbolic, celestial retreat, a Garden of Eden. This Islamic idea of gardens as places of sacred contemplation - and also places where water ran or stood still - spread outward as the new Islamic faith spread to North Africa, Central Asia, northern India (the Mogul Empire), and southern Spain.

Ms. Hobhouse points out, in her consideration of this "Persian legacy," that the Islamic gardens of Spain were less oases in a hostile desert and more reflections of the "fertile lands" of Iberia. Nevertheless, water was still a central feature.

This is clearly evident at the Patio de la Acequia, at the Generalife in Granada, Spain. Generalife was the 14th-century country estate of King Nasrid Muhammad III. Although this site has been considerably altered since then, water is still a central aspect of its charm. (See photo.) And archaeological research has shown that it was originally laid out in a traditional Persian pattern known as chahar bagh - divided into quadrants by water rills.