About:
Calculate the Synthetic Dimensionless Unit Hydrograph according to Soil Conservation Service (SCS).
\begin{equation}
T_l = 0.6 \times T_c
\end{equation}
\begin{equation}
T_p = \frac{D}{2} + T_l
\end{equation}
\begin{equation}
T_r = 1.67 \times T_p
\end{equation}
\begin{equation}
T_b = T_p + T_b
\end{equation}
\begin{equation}
D = 0.133 \times T_c
\end{equation}
\begin{equation}
q_p = \frac{2.08 \times 10^{-6} \times A}{T_p}
\end{equation}
Where,
$T_l$, time lag - $h$
$T_p$, time to peak - $h$
$T_r$, recession limb time - $h$
$T_b$, base time - $h$
$T_c$, concentration time » HYD_kirpich_tc() - $h$
$D$, unit excess rain-fall - $h$
$q_q$, Synthetic Dimensionless Unit Hydrograph peak flow - $\frac{m^3}{s}$
$A$, Watershed area - $m^2$
 |
| ©WETpython, 2015 |
Module: Hydrology
Function: HYD_scs_duh(l,s,area)
Definition of variables:
- l, river lenght - m;
- s, river slope - m/m;
- area, watershed area, m2.
Sample code:
from Hydrology import *
l = 69200 # (m)
s = 0.00387 #(m/m)
area = 225*10**6 #(m2)
(tc, d,tp,tr,qp, duh) = HYD_scs_duh(l,s,area)
print("tc:", tc, "h") # concentration time
print("d:", d,"h") #
print("tp:", tp,"h")
print("tr:", tr,"h")
print("tb:", tp+tr,"h")
print("qp:", qp,"m3/s")
time = 0.0
print ("***Synthetic Dimensionless Unit Hydrograph***")
for i in range(len(duh)):
print("time|flow (h|m3/s):",time,"|", duh[i])
time += d
Result:
tc: 14.479812877695796 h
d: 1.925815112733541 h
tp: 9.650795282984248 h
tr: 16.116828122583694 h
tb: 25.767623405567942 h
qp: 48.49341285118252 m3/s
***Synthetic Dimensionless Unit Hydrograph***
time|flow (h|m3/s): 0.0 | 0.0
time|flow (h|m3/s): 1.925815112733541 | 9.676855077580308
time|flow (h|m3/s): 3.851630225467082 | 19.353710155160616
time|flow (h|m3/s): 5.777445338200623 | 29.030565232740926
time|flow (h|m3/s): 7.703260450934164 | 38.70742031032123
time|flow (h|m3/s): 9.629075563667705 | 48.38427538790154
time|flow (h|m3/s): 11.554890676401246 | 42.76424062705119
time|flow (h|m3/s): 13.480705789134788 | 36.9697166285001
time|flow (h|m3/s): 15.40652090186833 | 31.175192629949013
time|flow (h|m3/s): 17.33233601460187 | 25.380668631397928
time|flow (h|m3/s): 19.258151127335413 | 19.586144632846842
time|flow (h|m3/s): 21.183966240068955 | 13.791620634295757
time|flow (h|m3/s): 23.109781352802496 | 7.997096635744673
time|flow (h|m3/s): 25.035596465536038 | 2.2025726371935885
time|flow (h|m3/s): 26.96141157826958 | 0.0 |
| ©WETpython, 2015 |
