124 Neb. Admin. Code, ch. 5, § 004
All dike surface areas from the design high operating waterline to the outside toe of the dike and all other areas which were disturbed during construction will be seeded or sodded, and a grass cover maintained to prevent soil erosion. Short grasses, such as blue grass are preferred and will be mowed frequently to prevent overhanging vegetation. Alfalfa and long rooted grasses which might damage the integrity of the lagoon will not be used. Weeds, cattails, reeds, and other wetland plants will be removed by physical or chemical treatment as they emerge. Trees will not be allowed to grow within a horizontal distance of at least 50 feet as measured from the high water mark for the maximum operating depth of the lagoon, but not less than 10 feet horizontal distance from the outer dike toe of the lagoon.
124 Neb. Admin. Code, ch. 5, § 004