No lake it is the melt off from the mountains and the flow changes weekly. I was there in Feb 2018 and parts were frozen. Spring is the best time to play in the water but it is very cold.
San Luis Lake State Park is near the dunes
There is a creek that runs beside the dunes it's caused from snowmelt. End of May into June is the best time to go. but I've heard depending on the rain throughout the year it can be fun even into October.
The creek that runs just by the dunes can be quite nice to splash around in during the rainy season. The dunes themselves, however, are very dangerous during a thunderstorm. So word to the wise -- if you hear thunder, take cover.
No lake just sand creek size is dependant on time of year.
There is a creek that runs through. Different amount of water during the year. We just left 9/17/17 water was low and just enough to wade in.
It depends on the time of year and how much water has run off from the river. Over Memorial Day weekend, it was like a small stream to dip your feet into, but not really swim.
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