Over the course of the spring I’ve been watching a playa on the western edge of Amarillo. I know the landowner and have permission to go to the edge of it, but no farther, which is fine. Last summer and fall the playa filled to the brim, it was lapping the edge of the road. Alas, in my opinion, the city pumped it out in anticipation of laying a new sewer line for a western suburb and the lake has not (yet) refilled. Even so, you can see some interesting features and changes.
The first image was taken back in early April.
Last fall, the water reached several feet past the edge of the brown, coming closer twice. You can see a few details of interest. The land slops away from you, the viewer, then rises again in the distance. This is the basin of the playa. This area is not nearly as flat is it sometimes seems, and this is one of those not-flat bits. Before development got started in this section five years ago, this playa drained about three square miles, as best I can tell from topographic maps. When you get closer to the center of the playa basin, you will see that the plant communities shift, each inner ring needing more water and for longer, until you hit arrowhead and cattails in the center.
This gives you a better sense of the slopes, and that this is native grass pasture at the moment. The wires are down from the fence because of the sewer mapping. Beyond The Tree, you see unripe winter wheat. This was a great wheat year, so of course the farmers are sighing about low prices.
Now you see the same bit, more or less, in early June 6 hrs after a 1″ rain. The distant wheat is much more golden and harvest is starting as I type. In the foreground you see dead grass, then healthy native grasses and some weeds. Beyond the fence line the color changes as you shift from short grasses (gramas, buffalo grass, spartina) to forbs and some sedges.
You can see the weeds, in the nightshade family, that are the dark green before you get to the pale green of the warm-season native mid-grasses. I did not go any farther because it was getting muddy, and one person had already stopped to ask what I was doing. “Grass quality survey” was an acceptable and true answer. There seemed to be a bit of standing water way out in the bottom of the playa basin, but I wasn’t dressed for it and did not have permission to go past the fence line. Again, if you turned the clock back 8 months, I would have been standing with my lower-legs in the water.
Technically this is called a dry playa, meaning that it has water after major rains and then dries out over the course of the summer. Wet playas usually are deeper, larger, and/or have springs in them, or did before irrigation started. I enjoy watching it change over the year. Several kinds of ducks, geese, and other waterfowl use the playa, and the fields are full of meadowlarks, red-wing blackbirds, barn swallows, flycatchers, jackrabbits, coyotes, marsh hawks, another things.
Starting to combine wheat, already. It is things like that that remind me we live in two totally different parts of the country. I don’t think that even winter wheat is getting heads here, yet, and wheat won’t be ready to harvest until fall.
Yep! The custom cutters start down here and roll their way up into Canada over the course of the summer and fall. Someone had quite a sense of humor to have the High Plains wheat harvest coincide with hail season.
Interesting observations, thanks for the lesson! 🙂 How long does it take for that particular playa to dry up?
From brim full to when they started pumping a month later, it had receded about a yard. I’d guesstimate that the core is about 40 acres. Without pumping I suspect it would have needed roughly 7-8 months to go dry, meaning until there was not an open core of water. You can tell that the inner area is still boggy even though the spring/summer has been dry.
So probably something in excess of 30 million gallons of water, if one assumes 120 acre feet of water in there and nominal evaporation rates…
Yes. The pan evaporation rate yearly average is 90″. Somewhere I’ve got all my notes with the conversion figures for all the hydro equations. Somewhere.
Don’t worry about it, I went down that rat hole already… LOL