Rain Water Survey
For the second time this year I have taken a stab at calculating how much rainwater is in our fishpond.
Moya and Kate have done a remarkable job of populating “Cuba” with vegetables, and we have done our best to supply their garden with rainwater from the pond.
Watering gardens out of elevated totes is easy to comprehend. You can tell when you catch 275 gallons on a good rain, and you can tell when you have delivered it all to the garden.
It’s a different story for a pond.
We manually pump rainwater out of the pond into an elevated tote on a homemade water tower, and it gravity feeds Cuba. It is easy to know home much water we pump, and it is wonderful feedback on how hard it is to deliver water to where it is needed, but one of the unanswered questions is how much water is in the pond.
On both occasions I have turned to Cornell University. They have a Commercial Farm Pond Management Series that seems to provide the most clarity.
To survey the pond my friend Gary and I ran a rope from end to end and side to side. It is about 63′ by 70.’ Small pond. We then launched Sage on a kayak to take depth samples. This was daring on her part, since the pond is known to be packed full of giant catfish and water snakes. She pulled four depth samples across each axis.
Zafer, Arlo and I did the same thing earlier this year, but we lost the data.
Today the pond is down about a foot and a half. We calculated that when it is at the top of the standpipe it would hold 70K gallons of water. We have put a valve on the end of the standpipe, which allows us to raise the water level to the top of the dam. Our projection when full is 120K gallons of water.
We need to learn this stuff. If the average wasteful American consumer requires 80 gallons of water per day, it is good to know how much our unsustainable family consumes. It is fascinating to note that when pumping the water by hand, early indications are that consumption would drop precipitously.
And we need to learn this because we need to build a system for Jason and Haruka at Edible Earthscape. They are about to bring another two acres of cultivation along, and it is to be rain water powered-from a pond.
Next thing to implement is filtration. Pond water is full of algae and pollen and scum and stuff that will plug drip tape and soaker hoses. We will probably need to hold that back with sand, or something. We are not there yet. The last issue of 15-501 Magazine featured Arlo in a rain water collection article. While they might not print it if it wasn’t true, the reality is we have a long way to go before we have our heads around rain water delivery systems.
Once we have that figured out, we can move on drag coefficients and pressure losses and gallons per acre for maximum yield.
For now it is good to know how much water fits in a pond…
Original post by Lyle