Geoscience Reference
In-Depth Information
(a)
(b)
Yuba River
(Narrows near Smartsville)
(i)
1775
260
250
1820
240
Yuba River (Marysville)
60
50
1861
40
Sacramento River (Sacramento)
1899
10
0
1850 1870 1890 1910
Year
1948
(ii)
30
60
Yuba River
1976
20
50
1980
N
10
40
1984
Sacramento
River
Tributary streams
Active gravel area
Terrace
metres
0 500
0
30
1850 1900 1950
Year
Case Fig. 3.2
(a) Changes in low-flow channel bed elevations along the Yuba and Sacramento Rivers, California: (i) Gilbert's
(1917) original data (modified from Gilbert 1917); (ii) additional work by Graves & Eliab (1977) that uses and extends Gilbert's
data (modified from Graves & Eliab 1977). (Figures adapted from Miller 1997.) The plots illustrate active transformation of the
rivers by channel bed aggradation and subsequent degradation. (b) Channel changes (plan view) between 1775 and 1984 on
the River Nent, north-east England. Active transformation has resulted in a change from a single thread to a braided channel, and
deposition of fine-grained mining waste. Subsequently the latter has been incised since sometime between 1948 and 1976.
(After Lewin and Macklin 1987.)
