Sizing a triangular channel for complete volume retention:
L = 151 , 400 Q p 5 8 m 5 8 S 3 16 n 3 8 ( 1 + m 2 ) 5 8 f {\displaystyle L={\frac {151,400Q_{p}^{\frac {5}{8}}m^{\frac {5}{8}}S^{\frac {3}{16}}}{n^{\frac {3}{8}}\left({\sqrt {1+m^{2}}}\right)^{\frac {5}{8}}f}}}
Sizing a trapezoidal channel for complete volume retention: L = 360 , 000 Q p { b + 2.388 [ Q p n ( 2 1 + m 2 − m ) S 1 2 ] 3 8 1 + m 2 } f {\displaystyle L={\frac {360,000Q_{p}}{\left\{b+2.388\left[{\frac {Q_{p}n}{\left(2{\sqrt {1+m^{2}-m}}\right)S^{\frac {1}{2}}}}\right]^{\frac {3}{8}}{\sqrt {1+m^{2}}}\right\}f}}}
![{\displaystyle L={\frac {360,000Q_{p}}{\left\{b+2.388\left[{\frac {Q_{p}n}{\left(2{\sqrt {1+m^{2}-m}}\right)S^{\frac {1}{2}}}}\right]^{\frac {3}{8}}{\sqrt {1+m^{2}}}\right\}f}}}](https://wikimedia.org/api/rest_v1/media/math/render/svg/d197798f249e489cb62a16d37179b50c5155a113)