I am looking for advice what to do with a pond we have on our property. According to the previous owner, it used to be 2-2.5 m deep (about two decades ago), but in the past years has been drying out. The current state could be described as 'wetland'. It lies in a depression and collects water when it rains, but during summer it becomes kind of a marsh or swamp.
The dimensions of the pond, measured from an older map, are about 2140 m² at max (about 1/2 acre) - too big to dig out manually with a shovel within a reasonable timeframe, too small to be ecologically essential.
The reasons for drying out are unclear, but a spring nearby has run dry as well. Other reasons might be the changing climate, less rain, and generally a falling water table in our area. If I dig a hole about 1.5 into the mud, I get water at the bottom.
On one hand, I definitely want a pond on our property. To revive it, we'd probably need heavy machinery and lots of clay to seal it. On the other hand, the way it has evolved is kind of a natural development, and it is a habitat for animals and plants that I do not want to disturb too much. Digging out tons of organic matter with an excavator would destroy that little ecosystem, but also allow to restart with a new one. A healthy pond might attract more living things than the current 'wetland'.
So basically the options seem to be a) to leave it as it is, or b) to do some serious earthworks, including to break the current ecosystem. Am I missing an alternative option between these two extremes? Could it work to excavate the pond in smaller sections (to minimize intervention), or would this be futile?
I am attaching a current photo and an outdated aerial view for illustration for the current state and for the layout of the land.
That is not very deep even if it was at its best. No doubt over the years as water runs into it it brings silt with it. I don’t know the climate where you are but where I am one inch per day can evaporate during this time of year.
So as it’s drying this grass is growing in there taking even more water than just evaporation. I think you must decide if you want the pond or the wetland. For me it’s no question that I’d rather the pond. If I thought the run off could fill it up I’d personally try to make it deeper. You already would have to have the dozer or excavator there.
Is there clay on the property? Could be that it never held water good.
Good point. Have you seen this pond full since you have owned it?
When I built my pond my neighbor got “mad” at me saying I messed the flow of the creek on her property. Year one zero water flowed past me into that creek. Now that it doesn’t have to fill from ground zero it flows like it always did.
There is no question, purely selfishly I would want the pond and not the wetland. Especially assuming that in the years ahead, average temperatures might keep increasing and rainfall might keep decreasing. But we did not acquire the property for personal entertainment only. If we would make major major interventions like excavating tons of soil, we would have to look for an approach going with the land, not against it. I guess that makes it a bit more challenging than planning a swimming pool in the backyard.
Regarding clay, no, we do not have this on the property. The soil is mostly sandy, but the bottom of the pond is rich humus. If it's solidified with some pressure, this humus layer works as a (weak) barrier for water. Water permeates through it, but more slowly than through unsolidied soil or sand. Clearly not as good as clay. The nasty question is if it still could suffice to keep enough water from seeping away. On the other hand, we use this humus as plant fertilizer. Not the worst to have an almost infinite supply of natural fertilizer at hand ;-)
Regarding water diversions upstream, there is no creek nearby, but a trench connected to a (now dried out) spring. That (former) trench crosses the property in the middle, and it is completely dry, not recognizable anymore to have carried water. That leaves two sources for water supply: Collecting rainwater and redirecting it downhill into the pond (distance: about 100m/110 yards), and pumping up groundwater. Both is possible as we have a well near the pond, and on the other side of the property we have a couple of building roofs - house, barn, shed - with rain gutters.
The previous owners did not collect rainwater. Our current plan is to collect rainwater in several rain barrels and direct the overflow into a small retention basin uphill (behind the buildings) to water our plants. The pond downhill would then become a second overflow reservoir. Probably no way to find out if there is more excess rainfall or more evaporation/oozing away than to try it out.
Though that leaves the question if there is a method to dig out the pond more efficiently than with a shovel but without heavy machinery. How would our ancestors have approached the task of clearing out a dried out pond?
Your ancestors would have used a horse and a drag bucket, I have a few here, it was hard work.
I would not contemplate a shovel.
Perhaps some research locally and via the internet will give you some ideas that will work.
That sand will need special techniques applied to the area to ensure it holds water.
I use 20,000L tanks to capture rainwater, what size barrels are you thinking oif?
John Daley Bendigo, Australia
The Enemy of progress is the hope of a perfect plan