They are generally constructed with a hump in the floor. This prevents the animal from jumping into the dip, and gives the necessary length to the slide, without increasing the depth of the tank. Choose the proper dimensions from the [diagrams and table] according to whether the tank is to be used for horses, cattle, sheep, or hogs.
The lengths given will keep the animal in the tank one minute, usually a sufficient time to cure mild forms of disease. Where a longer treatment is desired, most ranchmen, instead of building tanks of greater length, provide a drop gate working in a groove, as [shown in the photograph], by means of which the animal is kept in the tank as long as necessary. Likewise, rather than build a separate tank for sheep and hogs, stockmen insert a temporary division fence, running the full length and depth of the cattle and horse tank. This fence should be solid and so spaced as to prevent hogs and sheep from turning around in the tank. In this way a single dipping tank may be used for horses, cattle, sheep, and hogs.
Dig the deep part of the hole first, and then slope the earth for the slide and climb. Lay the outlet drain pipe so that the top of the elbow bend will be even with the surface of the finished concrete bottom. Tamp back the dirt thoroughly about the drain tile before placing concrete.
The side walls only will require forms. If the banks stand firm, inside forms alone will be needed. Make these of 1-inch boards on 2 by 4-inch uprights. Steel reinforcing, preferably wire cloth or hog wire, is placed in the forms so that it will be embedded in the center of the concrete wall. Floor, sides, and ends should all be thus reinforced to prevent settlement cracks due to any settlement of earth foundations. Mix the concrete 1: 2: 4 and lay the floor and slopes directly on the solid earth. No fill is necessary. The concrete for the sloping ends should be mixed fairly dry so that it will tamp well and stay in position without the use of forms. With the bottom and slopes built, lower the side wall forms into the pit. Take care to jar no dirt upon the concrete already placed. Space the forms properly and cross-brace them firmly upon each other. Fill the wall space with concrete.
In placing this concrete, be sure that it strikes the wood form instead of the earthen side, as concrete mixed with earth makes a weak, leaky wall. Carry the walls 6 inches above the surrounding ground to prevent flood water from running into the tank.
The entrance slope should be smooth to slide the animals into the tank without skinning them up. Finish this surface with a wooden float and steel trowel. Some ranchmen prefer to cover the entire slide with a polished steel plate, the edges of which are sunk into the concrete when the slide is built. To aid the animals in climbing out, embed in the concrete the turned-up ends of iron cleats bent at right angles similar to a capital “U.” Old wagon tires, cut in lengths not greater than 20 inches and turned up 4 inches at each end, will do. Leave 1 inch clearance between the flat surface of the cleats and the concrete. Space the cleats 18 inches for horses and cattle and 10 inches for sheep and hogs.
At the leaving end of the tank, lay out the two dripping pens with their division fence on a line with the center line of the tank, so that a gate hung to this fence may close either pen, when it is full, and allow the animals from the tank to pass to the empty pen. Use concrete posts for the fences, as they will require no replacing. Excavate for the drainage foundation, set the posts, and build a 6-inch concrete floor according to the directions given under [Sidewalks], page 28, and [Feeding Floors], page 43. Slope the floors, ¼ inch to each foot in length or width, so that the dip running off the animals will be saved and returned to the tank. Corrugate or groove the floor to the depth of ½ inch, every 8 inches, in one direction. During the construction of the floor, mold around the outside a concrete curb, commonly called a splashboard, 6 inches above the floor and 4 inches wide. Where the dip from the floor empties into the tank, place a removable wire screen or strainer to keep the droppings and wool tags out of the vat. Cure the floors and slopes according to directions under [Feeding Floors], page 43. The wall forms may be removed after one week, but the tank should not be used until it is three weeks old.
