Environmental Engineering Reference
In-Depth Information
Table 4.1 Geographical characteristics of the Ubaye River [
3
,
4
]
Stream order
5
Length (km)
82
Watershed area (km
2
)
970
Watershed geology
Flysch and black marls
Mean annual discharge at Barcelonnette
(m
3
.s
-1
)
10.9
1 in 1.5 year discharge
a
(m
3
.s
-1
)
62(B.H.)
1 in 10 year discharge (m
3
.s
-1
) (B.H.)
a
130
Hydrological regime (Parde 1995)
Snow regime influenced by Mediterranean
climate
Altitudes (m)
900-1210
Slope (m per km)
12.92
Stream power (w.m
-2
)
b
c
30-40
å 400-600
Sinuosity rate
1.06
a
Gumbel adjustment
b
In the braiding segment, In the downstream gorges
c
B.H. HYDRO data bank/Barcelonntte station (1903-1990)
According to Parde [
3
] and [
4
], the Ubaye River is characterized by a transi-
tional snow regime. The maximum rainfall in the summer combines with a sec-
ondary peak in autumn. The whole area is located at a high altitude (900-1200 m).
The alluvial corridor, oriented west-east, becomes progressively narrower
downstream, as the last 6 km before the confluence is in gorges. This steep cor-
ridor is controlled by alluvial fans, many of which are no longer active. In open
parts of the basin near Barcelonnette, the river has an active channel of roughly
300-400 m in width. In narrower sectors, such as the Thuiles-Meolans segment,
the channel meanders. This amplitude becomes increasingly constrained by the
valley's narrowness downstream, while the fluvial pattern becomes less sinuous
and straight [
3
-
5
]. Figure
4.2
shows the Ubaye River with a floodplain area as a
selected case study.
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