I kayaked down from the Hope R bridge. You can smell sulphur about 1 km above the gorge, even in a strong westerly, so there are springs well up river above the Horseshoe Springs, somewhere. As you approach the gorge, where the Glenhope access road starts to head uphill on river L, look for warm seeps in the gravel. If you trace these back you will find hot spots. Then go and get an excavator…… [Hugh Canard, NZ]