The History of Esculent Fish

by Roger North

The dimensions of these banks are governed by the manner of the hills rising; for if it be quick, then, to cover a competent quantity of ground, you must raise the bank higher, and consequently it must be made stronger, than when the ground riseth slow, so as a moderate height shall cast the water upon ground enough. And of this there will be great difference; for in some places, ten feet high shall cover as much as twenty feet in others. And this will be easily discovered by the water-level, used according to art, whereby you may stake the water-line upon the ground to any height; and so you will fix the determinate height of the bank.

I will suppose a medium, and that a bank, fourteen feet high at the center, will cover the quantity of ground. Then you must make your bank at the foot at least fifty feet wide, and so straitening by equal degrees on either side, bring it to sixteen at the top; and so you will have a sufficient slope, and the bank will stand firm and durable, scarce to be destroyed without as much pains and industry as made it.

By this proportion, pond heads of any dimension may be projected; the matter is not so nicely circumstanced, that a little more or less should signify. But it must be noted, that to make them too slight, is the greatest error, and most to be avoided; let them be rather made too strong, for then you have not only a more secure bank, but a more beautiful walk, and more room for wheel-carriage, besides a capacity of some wood; all which compensate the charge of what is superfluous.

Of securing your Banks.

If the bank be well made, and in sufficient dimension, nothing can hurt it, but great land-floods, or water-shots, which, if suffered to run over the bank, will carry away the fish, which in a warm flood will rise, and go with it to seek adventures, but also gurry holes in the back of the bank, and weaken it so much, that if the flood continues, it shall carry all away together.

For preventing of this mischief, there are two ways; 1. Grates at each end of the bank, planted upon the level that is to be the highest of the water. 2. Channels of diversion, which being taken so high in the current as may lead the water upon the side of either hill above the bank, you have the power to turn out all the water when you please, so that none shall come upon the bank.

1. As to grates, the way of them is well known; however observe, that if they be made of wood, the banks must be set diagonally, like window-bars; for so rubbish stops least against them, and the water passeth freely. And in regard you cannot allow any great distance between them for keeping in the fish, you must help out the room by extending the grate from each side of the cut in the bank where the water is to vent, some considerable space from the bank, and there to meet in a point, forming a triangle upon the bank. Here are many more slits for the water to vent at, than if the grate lay flat upon the bank, covering the passage only. And if need be, there may be doors to slide up and down, made in the grate, to let the water pass more freely; but this endangereth losing the fish. If you will afford iron for these grates, you need only cover the passage of the bank; for the bars need not be so thick, but there will be space enough for the water to vent at.

2. The channels for diverting the water are very useful in this and many other respects; for they give you a perfect command of the water, and you may turn it which way you please, so as to fill or keep dry any of the ponds, and in a wet season are a perfect security. These should be made four feet wide, and on each side of the ponds the loss of ground is not considerable; for wood growing there will make amends for it.

The string of ponds in Hyde-Park are admirably disposed in this respect; for the current of the valley is carried along by the side of all the ponds, and may be let into any of them, or any may be emptied into it; than which, there is not a greater command of water.