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378-6 Pond • 3. The conduit is of corrugated metal pipe larger than 12 in. in diameter. Antlseep collars and their connec- tions to the pipe shall be water- tight. The collar material shall be compatible with pipe materials. The cumber and size of antlseep collars shall be determined so that the line of seepage will be increased by 15 percent. The maximum spacing shall be approximately 14 times minimum pro- ~ection of the collar measured per- pendicular to the pipe. The minimum pro~ectioa of any collar shall be one (1) foot. Closed conduit spillways designed for pressure flow must have adequate an[ivortex devices. • If needed to prevent clogging of the conduit, an appropriate trash guard shall be installed at the inlet or riser. A pipe with a suitable valve shall be provided to drain the pool area if needed for proper pond management or if required by state law. The prin- cipal spillway conduit may be used as a pond drain if it is located so as to accomplish this function. Supply pipes through the dam to watering troughs and other appurten- ances shall have an inside diameter of cot less than 1 1/4 in. Headgates or Valves. Headgates or valves shall be installed at the pond end of the outlet conduit except far fish ponds with specially de- signed outlets. 'Galvanized steel supply pipes may have downstream valves, provided the pipe and valve are protected against freezSng. Emergeucy ep111waye. Emergency spillways convey large flood floes SCS, Colorado, April 1480 safely past earth emergency spillway around one or both unless an exemption State Conservation Colorado State Engi~ embankments. An must be provided ends of each dam is granted by the Engineer and the leer. The minimum capacity of a natural or constructed emergency spillvay shall be that_ required to pass the peak flow expected from a design storm of the frequency and duration shown in Table 3 less any reduction creditable to conduit discharge and detention storage. The spillway width-.require- ments established by the State Engineer of Colorado for Livestock LTater Tanks or Erosion Control Dans shall be assumed to meet these re- quirements for dams having less than 1,000 acres in the contributing drain- age basin, unless the spillvay will be located in easily eroded soils such as sands, silts, and silty sands. The emergency spillway shall safely pass the peak flow or the storm runoff shall be routed through the reservoir. The routing shall start with the eater surface elevation at the crest of the principal spillway or at the water surface after 10 days dravdown, which- ever is higher. The 10-day drawdow[t shall be computed from the crest of the emergency spillway or from the elevation that would be attained if the entire design storm were im- pounded, whichever is lower. Emer- gency spillways shall provide for passage of the design flow at a safe velocity to a point dowstream where the dam will not be endangered. Constructed spillways shall be trape- zoidal and shall be located in undis- turbed or compacted earth. The side slopes shall be stable for the mater- ial in which the spillway is to be constructed and shall not be steeper than 1 1/2:1 in earth and 1/4:1 in rock. (Side elopes in earth should