Geoscience Reference
In-Depth Information
Fig. 1. Watershed model for the upper part of the Asuwa River basin with the outlet
at the Tenjinbashi discharge station and its sub-basins which contribute to the river
segments of the Asuwa River. The locations are specified using UTM coordinate with
m unit.
of the discharge-stage relationship
3
as:
v
m
d
m
(
h/d
m
)
β
,
0
≤
h<d
m
,
q
=
(1)
v
m
d
m
+
v
a
(
h
−
d
m
)
,
m
≤
h<d
a
,
v
m
d
m
+
v
a
(
h
−
d
m
)+
α
(
h
−
d
a
)
m
,
a
≤
h,
where
q
is discharge with unit width;
h
the flow depth;
v
m
=
k
m
i
,
v
a
=
k
a
i
,
k
m
=
k
a
/
β
,
α
=
i/n
;
i
the gradient of slope segment;
k
m
the saturated
hydraulic conductivity for the capillary soil layer;
k
a
the hydraulic conduc-
tivity for the noncapillary soil layer;
n
the surface roughness coecient;
d
m
the capacity of water depth for the capillary soil layer; and
d
a
is the
capacity of water depth including capillary and non-capillary soil layer.
The model parameters to be determined are
n
(m
−
1
/
3
s),
k
a
(m/s),
d
a
(m),
d
m
(m), and
β
. For river flow routing, surface flow with rectangular cross
section is assumed for kinematic wave approximation.
