Calculation of Hydrologic Parameters Using CRWR-PrePro Francisco Olivera, PhD Center for Research in...
-
date post
21-Dec-2015 -
Category
Documents
-
view
213 -
download
1
Transcript of Calculation of Hydrologic Parameters Using CRWR-PrePro Francisco Olivera, PhD Center for Research in...
Calculation of Hydrologic ParametersUsing CRWR-PrePro
Francisco Olivera, PhDCenter for Research in Water Resources
University of Texas at Austin
Hydrologic Parameters
Watershed Abstractions and routing
method Parameters
Stream Routing method Parameters
Watershed Abstractionsand Routing Method
Abstractions: precipitation/excess
precipitation transformation
SCS curve number method
Initial loss + constant rate loss
Routing: excess precipitation/runoff flow
transformation
Soil Conservation Service (SCS) synthetic
unit hydrograph
Watershed Abstractions
Soil properties
Precipitation (mm)
Excess precipitation (mm)
Excess precipitation = f(Precipitation, Soil properties)
Watershed Routing
Excess precipitation (mm/hr)
Runoff flow (m3/s)
Time
Exce
ss
pre
cip
itati
on
an
d
Ru
noff
flow
Runoff flow = f(Excess precipitation, Watershed hydrologic properties)
Hydrologic Parameters
Watershed Abstractions and routing
method Parameters
Stream Routing method Parameters
Watershed Parameters
Area
Average curve number
Initial + constant rate loss
Length of longest flow-path
Slope of longest flow path
Lag time
Watershed Lag-Time (SCS)
t5.3,
S67.31
]9)CN/1000[(Lmaxt
5.0
7.08.0w
p
tp: lag-time (min)LW: length of longest flow-path (ft)S: slope of the longest flow-path (%)CN: average Curve Numbert: analysis time step
Watershed Lag-Time (L/V)
t5.3,
V60
L3048.06.0maxt
w
wp
tp: watershed lag-time (min)Lw: length of longest flow-path (ft)Vw: longest flow-path average velocity (m/s)t: analysis time step
Hydrologic Parameters
Watershed Abstractions and routing method Parameters
Stream Routing method Parameters
Pure-Lag Method
Flow is delayed a fixed amount of time tlag.
)t(I)tt(Q lag
tlag: flow time in the reachI: inflow to the reachQ: outflow from the reach
Muskingum Method
Flow is delayed a fixed amount of time K, and redistributed around its centroid.
QIdt
dSandQ)X1(IXKS
S: storage in the reachK: flow time in the reach (t < K < t/2X)X: storage parameterI: inflow to the reachQ: outflow from the reacht: analysis time step
Routing Method
Flow time (Ls/Vs)
Ls/Vs < t
MuskingumRouting
Ls/Vs > t
Pure LagRouting
Ls: length of the streamVs: flow velocity in the streamt: analysis time step
Hydrologic Parameters
Watershed Abstractions and routing method Parameters
Stream Routing method Parameters
Pure Lag Parameters
s
slag V60
Lt
tlag: flow time in the reach (min)Ls: reach length (m)Vs: reach average velocity (m/s)
Muskingum Parameters
K: flow time in the reach (hr) [Muskingum K]X: storage parameter [Muskingum X]Ls: reach length (m)Vs: reach average velocity (m/s)n: number of sub-reachest: analysis time step
s
s
V3600
LK
1t
V/L)3/1,X2max(intn ss