Alley construction in freestall barns where flushing is going to be used is extremely important. Alleys must have uniform slope from top to bottom and dips and pockets that cause water to lose velocity must be avoided. Having alley surfaces level from one side to the other is especially important with erosion-type flushing where lower volumes of water per unit of time result in shallower streams of flush water. At least some of the manure solids should be separated from the liquids before flushed manure enters storage. Pumping the manure stream over a sloped screen is one alternative.
Solids settling out in the manure storage are difficult to agitate and suspend.
However, solid-liquid separation increases both complexity and cost of the overall flushing system. Flushing is a convenient method for removing manure from a freestall barn. However, system design should be carefully thought out, including water sources, method of releasing water onto alleys, related barn construction features, provisions for separating solids following flushing and final disposition of flushed water and manure.