Las Cruces arroyo after a big rain
To live in the desert is to be aware of water. That seems obvious--living in a dry place, you learn to carry water at all times, to keep yourself hydrated, and to landscape with native or drought tolerant plants so that you reduce or eliminate the need for watering your yard.
However, when we first arrived in Las Cruces, we were surprised to find a great big earthen dam paralleling the highway. A dam in the desert? A dam with no water?
It's the Las Cruces Flood Control Dam and, as you can see from this cycling map (below), it is highlighted in red right next to Highway 25. Coming from a wetter climate, I am always interested to see that there are housing developments behind the dam--if this were a traditional dam like Hoover Dam, this is right where you would find Lake Mead.
You soon learn this about living in a dry place that gets just 8 - 12 inches of rainfall annually: When the rain does come, it sometimes comes hard and fast, drains off the mountains and mesas down into the river valley, and might lead to flooding if not otherwise diverted.
Back in the 1970s, the flood control dam was constructed. According to the City of Las Cruces Storm Water Management Design Standards, they are aiming for protection against a "100 year storm event."