CFS vs Gauge Height Debate

[tjm]

I have short legs too, but the thing is gage height is not absolutely the water depth- it is the water depth as measured from some unknown (to me)  level. Usually a tube in a stilling well fastened to a bridge and the zero point might be higher or  lower or at the low water level found in that bridge hole. Kinda like a float in a toilet tank it has limits of travel and it doesn't account for changes in bank width or bottom fill-in/erosion; in essence it measures the water relative to the bridge structure. By frequent surveying of the bridge hole and measure of velocity, hydrologists can calculate what volume of water that gage height means today and compare that volume with measured volume from past days/years. If the stream bed changes significantly, the change is accounted for by the surveying and calculation, while the gage continues to read the same  relative to the bridge.

Most every stream I have ever been on had a channel that was fairly defined and as the water gets lower the water becomes confined to that channel, so that while a drop of gage height by 6" might expose gravel bars, the cut channel may still have 4' deep water or 1' deep water and this is where volume of water counts regardless of bridge height. CFS tells me about how much water is flowing in the cut channel. 30-150 CFS is wadable fishing everywhere I've been. Less or more might still be fishable in some places but perhaps not so wadable, and I can picture that volume having never seen the stream. But more important is the comparison of today's flow with historical volumes, the 25th, 75th percentiles and the median flows- median is probably ideal and 75th is stay at home, for me at least. 

[jdmidwest]

I like the water temp feature.  We have been watching a stream to fish this weekend.  We hit a good pattern in winter when temp were 43 or less.  Rain brought river up some, but water temp went way up. I am banging on a tablet instead of in a jet boat right now.

[drew03cmc]

18 hours ago, Al Agnew said:

Drew, did you float a lot farther downstream than where the gauge is located?  

Yes. The put in is probably 20 river miles downstream. There is one or two creeks that come in there, but nothing truly sizeable. Yes, it was such a good float at that level we only drug maybe twice on a small river.