Advice : Swale/Pond in Disturbed Soil

Hi ! I need some advice on digging a water catchment swale or pond in disturbed soil, heavy clay to be exact. We have about 3/4 acre of land on 4 terraces. The first terrace, the one at the highest elevation, is made of disturbed land. Some of the rain water that we do get, which is on average 1 ft/annum, collects at the edge of this terrace and runs down to the next terrace. This has made a cut in the slope of the terrace edge. The slope is quite steep and about 12 ft high from the second to the first terrace and the cut isn't very deep, perhaps about a foot deep and 2 feet wide.

It does seem like the best place to catch the water, ie following nature and at a high point on the land.... but the disturbed soil will make it more difficult. So anyone with any advice out there ?

P.S. We live at about 2700 ft elevation in Andalucia Spain. In other words we have very hot summers, and winters where the temperature sinks below freezing most nights.
Thanks so much!
Linda

Linda could you post a picture?

Oh sure !! Give me a couple of days to sort it out. Thanks. Linda

Pictures would be great.

It doesn't sound any different than building a dam, except you have a very small space to start with.

Hi, thanks for waiting for me to load a photo editor and take some picks. I'm not sure how to lay this out, but here it goes. In pic #1, '3 Terraces', you can get an overview of the lay of the land. The blue lines are the tops of the terraces. I've added an indicator of roughly where south is, in case that's if interest. I have also shown where the erosion is by using a blue 'V'. In the 2nd and 3rd pics , I've tried to show the depression the leaking water has made on the top edge of the terrace and where the erosion is starting on the top of the terrace. The last photo is a side view of the slope of the 1st terrace down to the second. The blue circle is showing where the water is trickling through the top of the terrace and out of a hole in the terrace slope.

As I said before the top terrace is disturbed land from the 'amplification' of a cave house. It has been sitting for about 4 years and you can see lots of holes appearing where the earth is settling. I would say that terrace 1 is 'U' shaped and about 5 car lengths long and 4 wide. The second terrace is narrow....about 2/3 yards wide and about 30 long. It was made narrow by the addition of the spoils from the cave amplification. The third terrace is about 10 yards wide and 35 yards long and finally the 4th terrace is about 15 yards wide and about 40 yards long. These are very approximate. The cave house is further back on the first terrace. I havent included it or the front 'garden' in these calculations.

Any ideas would be greatly appreciated. We have waited a while to get going on this and want to get it as close to 'right' as possible. Thank you! !

That looks similar to what is done here by non-permies to make cattle ponds in pastures here in the midwest US. They usually put in an overflow pipe to keep the water from spilling over the edge. Or a rocked sill spillway, like a big swale.

There really isn't a lot of room for a pond, but the spoil from the hole will have to go somewhere--probably extending the second terrace into something usable--depending on what you want to use it for.

Linda, thanks for posting the pictures.

It looks like there is a house in the background? Is it at the same level as the highest terrace?

So you want to dig out a pond at the highest point? As you dig it out the soil will be added to the outside of the dam? As already stated by R Scott.

Seems like if you dug deep enough you could have a pond with the bottom equal in elevation with the lower terraces?

You just need to make sure to pack the soil that will be the dam, you do not want the force of the water to break the dam, and have some sort of spillway or pipe for overflow.

I think there are some great threads in the ponds forum that might help too.

https://permies.com/forums/f-89/ponds

Thanks to both of you, R Scott & Miles. I will do some thinking about your suggestions & thoughts. Thanks again.