Construction A picket dam must be well constructed since the manure will pile up against it to the depth of the storage. The dam is built with pressure-treated posts and horizontal stringers. As the storage fills with manure, the vertical slots remain continuously open, allowing free water to drain through. If horizontal slots are used for drainage, the openings will be sealed off periodically as the manure builds up in the storage, causing water to accumulate to the level of the next horizontal slot. Location Dam location is critical.
Water runs off accumulated manure to the sidewall and along the edge to the low point.
The picket dam must be located and sized to intercept and drain away water that runs off the manure pile. This usually requires the dam to start along one side of the bottom of the storage and continue up the unloading ramp. A slotted box structure located away from the edge of the storage does not work as well as one at the sidewall. Two or more picket dam drains may be needed where manure is loaded in the center of a large storage. Water should always have a drainage path from the face of the manure pile to the drain.