It's the end of June and, after three weeks of travel, I'm back at my desk in Kurohime up here in the beautiful hills of Nagano Prefecture.

It is nearing 8 o'clock in the morning, and not at all a dull day, but I have to switch the lights on in my study/dojo (exercise room) in order to read my field notes. This is because the trees around my study are so green and lush with leaves that they cut out almost all the direct light. This is a contrast with clear days in winter, when I have to pull a blind down on my south-facing window because of the glare of sunlight and snow.

From the window to my right, through small gaps in the trees I can see the Torii River gleaming white with rapids. All kinds of birds flit through the foliage, and in the high canopy small, white day-flying moths flutter in their thousands.

When I got home the other night, the river was in flood, due to the heavy rains. It rushed and roared, almost 2 meters higher than it is now, and although the river is just a stone's throw from this room, I wasn't at all worried.

When I built this place, which is less than 100 meters from my house, I noted the slope of the land and concluded that, if the river should ever overflow (which it has done just once since), the floodwater would fan out and dissipate its force and depth. However, I built on ground that has some huge boulders deeply embedded in it, rocks so big that we would have had to blast them to get them out. The ground floor has thick walls of reinforced concrete, fixed on these rocks. In the heaviest flood in 25 years we didn't even get more than a little damp on the ground floor, and the rest of the building was fine.

However, a lot of people all over the world ignore good sense and tradition and build or buy their homes in very vulnerable flood plains.

This month, thanks to All Nippon Airways, I took a tour of Japanese friends and members of the C.W. Nicol Afan Woodland Trust on a first visit to our "sister" forest in Wales (The Afan Argoed Forest Park in Glamorganshire, South Wales), and then to see some very special flood-protection work.

Despite the strong advice and protest against doing so by the Environmental Agency of England and Wales, developers built and sold expensive homes in areas very vulnerable to flooding in and around the towns of Maidenhead, Windsor and Eton in Berkshire. Some 6,500 homes were at risk, and the Environmental Agency pushed a highly complex construction scheme costing £110 million (¥24,200 million) to alleviate this flood threat. The project was named for the Queen's Jubilee celebrations in 2002, at which time the main construction was scheduled to be finished. The Environmental Agency official in charge of this was Alastair Driver, the son of Dr. Peter Driver, my former biology teacher. It was with Peter Driver that I first went to the Canadian Arctic in 1958 and 1959, when Alastair was still a small boy. Between expeditions, I baby-sat the lively little lad several times. He is now a husky athlete and national conservation manager of the Environmental Agency of England and Wales.

It was pure chance that enabled me to renew my friendship with Alastair. Eighteen years ago, I was filming a documentary for Japanese television on the River Thames in England when we ran into each other after a gap of about 30 years. Alastair was in charge of improving the water quality and biodiversity of the river, and he and his team were replacing sterile concrete banks with willows and rushes. It was through modern pollution control and this kind of work that it became possible to reintroduce salmon to the Thames.

We kept in contact, and Alastair became a board member of our woodland trust here in Japan. It was through him that I learned of the new Jubilee River and was determined to take some interested Japanese to see it.

The Jubilee River is 12 km in length and averages 45 meters in width. It was 13 years in the planning and took four years to construct. Excess water is taken via the east bank of the Thames upstream of Boulter's Lock and returned via the northeast bank downstream of Eton. One of the many construction problems was to take the river through the embankment and under the main railway line linking Bristol and London. This was achieved by freezing the embankment, boring through, then inserting a preformed concrete culvert. This was one of many highly complex civil-engineering tasks.

In order to enhance wildlife and the visual beauty of the new river, 38 hectares of reed beds and 5 hectares of wet woodland were laid down. About 250,000 trees were planted. Bridleways, footpaths, bridges, boardwalks, pond-dipping platforms, angling facilities and access for the disabled, for canoes and so on, were all provided. In this new habitat, wildlife flourishes. Terns, plovers, reed warblers, sedge warblers, reed buntings, skylarks and ducks have come to breed. Grebes, snipe and golden plover arrive in winter. Otter spraints have been found on the banks. Twenty-one species of butterfly have been recorded. Dragonflies, of course! A quarter of a million humans live within a 16-km radius of the river, so it has become a major recreational asset. Looking at the new river, it is easy to forget that it all started out as a flood-protection scheme.

When our tour from Japan, guided in person by Alastair, visited the Jubilee River, it had been less than six years since the new river had been officially opened, but it looked as if it had always been there — natural, and not a bare, ugly concrete monstrosity of the type with which we are familiar in Japan. This project not only protects homes, it improves the lives of the people there, not to mention increasing property values.

From a grassy, man-built hillock, with skylarks warbling above, and with the royal pennant flying over Windsor Castle in the distance, we could look down at this new river, lively as it was with herons, ducks, geese and swans. Almost all of us from Japan could not help but sigh and draw comparisons with the eyesores that have been created out of so many formerly beautiful Japanese rivers.

They would have done such ghastly things to the Torii River that flows beside me now. This noisy old red devil, however, made a huge fuss and recruited the advice and help of Shubun Fukutome, president of the West Japan Scientific Research Company Ltd., based in Kochi, Shikoku. Fukutome is probably the leading environmental river engineer in Japan. Thanks to his advice, the flood-protection construction on our little river was changed from the usual simple concrete slopes and weirs to the use of interlocking natural boulders, placed in order to create pools and back eddies. This has enabled aquatic insects, fish, birds, willows and rushes to return to the river and thrive, and it has also created some fine watery places for children to play in the summer. Had we left it to the government plans, it would have been a concrete ditch. I have to say, too, that out of a population of 11,800, many of whom are anglers, mine was the only voice raised against those river-destroying plans, which made me as many enemies as friends. However, one of the results of the Torii River construction was that the local construction company got a prize and a commendation from the Ministry of Environment in Tokyo, as indeed did Mr. Fukutome. I didn't get any award, but I got the far better prize of a living river to enjoy just outside my study window. I get the satisfaction of proving my original point: It is not sensible just to protect property from water by making it sterile and ugly. I also became great friends with the local construction company, and so progressed from being "that damn foreigner" to "Nicol sensei (teacher)."

I feel that I must add that, as an avid kayaker, one of the most dangerous situations to get caught in on a river is when you have a flood and you need to get out of the water, but are faced with steep, slippery concrete banks and nothing to grab hold of. Willows, reeds and other aquatic plants — well set in firmly locking rocks — are much easier to deal with. You could say the same thing for somebody falling in the river and getting swept down, too. Smooth, wet concrete slopes are bloody dangerous!

Environmentally sound and pleasing river-enhancement work can be done in Japan; there's no excuse for destroying not only the environment but also extremely valuable freshwater fisheries and recreation resources.

It's easy to blame the government, but the way I see it, public apathy is even more at fault. Actually, I have met lots of young officials who are keen to improve things, but they need support. If you have a river or a stream nearby, think about it, and make your feelings known!