Why does the lake level fluctuate so much?

[gdelmoro]

I thought that the power company could (did) pump water back into the lake and that unlike other dams this one had the ability to maintain the water level at Smith Mountain? You would think, (given a normal rain fall) SML could be kept between full and normal pond MOST of the time.

[mwardncsu]

Various factors - they typically keep SML within a foot of level - during lower-periods of demand you'll see the level drop across a week and then pump back up on Sunday - during high-demand period (like now in the summer when AC's are cranking wide open), there is bascially a daily generation cycle for drain & pump-back, with a weekly overlay trend to it.

However, they still have to maintain certain downstream flowage amounts - which I believe vary across the time of year (i.e. during the Spring when striper are spawning they are required to keep a certain amount of flow downstream at Brookneal - which hurt us a few years back when the flow-gauge was broken and they let a LOT more water out downstream for an extended period than they needed and then we hit a dry summer). As such if we don't have enough rain upstream means the lake level will gradually drop. I think there are also cases where they are doing some maintenance at the dam or perhaps other things (maybe public ramps) where they will draw it down a bit more than normal for a couple of weeks - though not to the extreme that a lot of reservoirs have with winter-time maintenance draw-downs

You can look at current historic levels here - smithmountainlakelevel.com/ - changing the periods of time. It's pretty typically for late summer/early Fall for us to be below Normal pond with a gradual drop towards an average of 793 if not lower - and then it rises back in the winter months when we get more precipitation again

Overall we can't complain with a foot +/-, and an "extreme" for us is a 4-5' drop - when Leesville swings that much weekly Of course our docks are mostly build as fixed docks vs floating so getting out of your boat when the lake is down 4' can be interesting (assuming you even have the water to get back in your slip).

[gdelmoro]

Thanks Mike!
I watch that site and the hales ford weather wife for lake info. Of course I watch this and the SMSC boards for all kinds of good info