Hah. I watched a documentary one time on some wasabi greenhouse growing operations in western oregon. Or was it washington? Anyway, it was pretty cool, it grows in really wet rocky soil like yours, Steve. Think shallow streambed conditions.
@NwMtGardener Heather, there was somewhere I saw pictures of small terraced fields in Japan. It may have been on a north slope. There was obviously plenty of water. It was a wasabi growing operation.
I've grown water cress in a little pond I created and brought water from a leaky irrigation valve. The valve was replaced and so ended a source for 24/7 water.
The Asian markets have these real tasty snow pea snacks, too .