[pct-l] Hat Crrek Rim water

[dave at livebythepark.com (David Davis)]

All of the recent Giardia talk has me wondering about the water on Hat Creek Rim.  A big (but aged) sign warns not to drink surface water.  The guide book does the same.  What could be so much worse about the mud puddles on the Hat Creek rim than the mud puddles anywhere else?  Last week I passed at least 4 water sources on the "dry" 30 mile section that everyone dreads.  Is there something I don't know about?  Chemical pollution?  Volcanic salts?  It looks like the cows can drink the water OK.  Why not people?