Journal of Geographical Sciences >
Adjustment in the main-channel geometry of the lower Yellow River before and after the operation of the Xiaolangdi Reservoir from 1986 to 2015
Wang Yanjun, PhD, specializing in geomorphology and fluvial processes. E-mail: yanjun1113@126.com |
Received date: 2019-10-31
Accepted date: 2019-12-10
Online published: 2020-05-25
Supported by
Key Program of National Natural Science Foundation of China(No.51639005)
National Key R&D Program of China(No.2017YFC0405202)
National Key R&D Program of China(No.2016YFC0402406)
Copyright
Based on the measured discharge, sediment load, and cross-sectional data from 1986 to 2015 for the lower Yellow River, changes in the morphological parameters (width, depth, and cross-sectional geomorphic coefficient) of the main channel are analyzed in this paper. The results show that before the operation of the Xiaolangdi Reservoir (XLDR) from 1986 to 1999, the main channel shrunk continually, with decreasing width and depth. The rate of reduction in its width decreased along the river whereas that of depth increased in the downstream direction. Because the rate of decrease in the width of the main channel was greater than that in channel depth, the cross-sectional geomorphic coefficient decreased in the sub-reach above Gaocun. By contrast, for the sub-reach below Gaocun, the rate of decrease in channel width was smaller than that in channel depth, and the cross-sectional geomorphic coefficient increased. Once the XLDR had begun operation, the main channel eroded continually, and both its width and depth increased from 2000 to 2015. The rate of increase in channel width decreased in the longitudinal direction, and the depth of the main channel in all sub-reaches increased by more than 2 m. Because the rate of increase in the depth of the main channel was clearly larger than that of its width, the cross-sectional geomorphic coefficient decreased in all sub-reaches. The cross-sectional geometry of the main-channel of the lower Yellow River exhibited different adjustment patterns before and after the XLDR began operation. Before its operation, the main channel mainly narrowed in the transverse direction and silted in the vertical direction in the sub-reach above Aishan; in the sub-reach below Aishan, it primarily silted in the vertical direction. After the XLDR began operation, the main channel adjusted by widening in the transverse direction and deepening in the vertical direction in the sub-reach above Aishan; in the sub-reach below it, the main channel adjusted mainly by deepening in the vertical direction. Compared with the rates of decrease in the width and depth of the main channel during the siltation period, the rate of increase in channel width during the scouring period was clearly smaller while the rate of increase in channel depth was larger. After continual siltation and scouring from 1986 to 2015, the cross-sectional geometry of the main-channel changed from wide and shallow to relatively narrow and deep. The pattern of adjustment in the main channel was closely related to the water and sediment conditions. For the braided reach, the cross-sectional geomorphic coefficient was negatively correlated with discharge and positively correlated with suspended sediment concentration (SSC) during the siltation period. By contrast, the cross-sectional geomorphic coefficient was positively correlated with discharge and negatively correlated with SSC during the scouring period. For the transitional and meandering reaches, the cross-sectional geomorphic coefficient was negatively correlated with discharge and positively correlated with SSC.
WANG Yanjun , WU Baosheng , ZHONG Deyu . Adjustment in the main-channel geometry of the lower Yellow River before and after the operation of the Xiaolangdi Reservoir from 1986 to 2015[J]. Journal of Geographical Sciences, 2020 , 30(3) : 468 -486 . DOI: 10.1007/s11442-020-1738-3
Figure 1 Sketch of the study area (modified based on No. GS (2016)2893, downloaded from http://bzdt.ch.mnr.gov.cn) |
Table 1 The distribution of the cross-section in different reaches in the LYR |
Reach | Above HYK | HYK-JHT | JHT-GC | GC-SK | SK-TCP | TCP-AS | SK-AS | AS-LK | LK-LJ |
---|---|---|---|---|---|---|---|---|---|
River length (km) | 103.17 | 100.80 | 72.63 | 118.20 | 35.63 | 28.24 | 63.87 | 101.84 | 167.80 |
Number of cross-sections | 11 | 10 | 7 | 13 | 9 | 7 | 16 | 13 | 22 |
Figure 2 Typical cross-sectional profiles of the lower Yellow River and partitions of the main channel |
Figure 3 Temporal changes in water and sediment conditions in the lower Yellow River |
Figure 4 Cumulative erosion and sedimentation per unit river length in different reaches of the main channel |
Figure 5 Changes in the width of the main channel in different reaches from 1986 to 1999 |
Figure 6 Changes in depth of the main channel in different reaches from 1986 to 1999 |
Figure 7 Changes in the width of the main channel in different reaches from 2000 to 2015 |
Figure 8 Changes in the depth of the main channel in different reaches from 2000 to 2015 |
Figure 9 Changes in cross-sectional geomorphic coefficient in different reaches |
Appendix Table 1 Annual post-flood main-channel cross-sectional geometry parameters for different sub-reaches of the lower Yellow River from 1986-2015 |
Year | Main-channel width (m) | Main-channel depth (m) | Main-channel cross-sectional geomorphic coefficient (m-0.5) | ||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Above H | H-J | J-G | G-S | S-A | A-L | L-li | Above H | H-J | J-G | G-S | S-A | A-L | L-li | Above H | H-J | J-G | G-S | S-A | A-L | L-li | |
1986 | 1575 | 2489 | 1905 | 862 | 624 | 493 | 462 | 1.72 | 1.78 | 1.95 | 2.82 | 3.64 | 4.52 | 3.93 | 23.06 | 27.98 | 22.34 | 10.39 | 6.86 | 4.91 | 5.47 |
1987 | 1621 | 2393 | 1907 | 871 | 629 | 490 | 463 | 1.62 | 1.70 | 1.84 | 2.79 | 3.44 | 4.38 | 3.80 | 24.91 | 28.83 | 23.71 | 10.56 | 7.30 | 5.06 | 5.66 |
1988 | 1184 | 1684 | 1126 | 675 | 611 | 469 | 441 | 1.85 | 2.08 | 2.35 | 3.09 | 3.60 | 4.81 | 4.11 | 18.63 | 19.75 | 14.28 | 8.42 | 6.87 | 4.50 | 5.11 |
1989 | 1362 | 1940 | 1067 | 685 | 614 | 464 | 437 | 1.77 | 1.69 | 2.33 | 2.81 | 3.39 | 4.41 | 3.70 | 20.90 | 26.13 | 14.04 | 9.32 | 7.32 | 4.88 | 5.64 |
1990 | 1165 | 1604 | 969 | 712 | 589 | 463 | 439 | 1.78 | 1.59 | 2.08 | 2.69 | 3.30 | 4.27 | 3.54 | 19.18 | 25.23 | 14.94 | 9.91 | 7.36 | 5.04 | 5.92 |
1991 | 1310 | 1432 | 900 | 678 | 583 | 465 | 438 | 1.57 | 1.54 | 2.05 | 2.72 | 3.12 | 4.05 | 3.30 | 23.11 | 24.62 | 14.60 | 9.59 | 7.73 | 5.32 | 6.34 |
1992 | 859 | 1226 | 707 | 556 | 437 | 413 | 386 | 2.33 | 1.67 | 2.32 | 3.23 | 3.33 | 4.21 | 3.67 | 12.60 | 20.91 | 11.47 | 7.31 | 6.28 | 4.83 | 5.36 |
1993 | 978 | 1479 | 781 | 535 | 450 | 396 | 378 | 2.17 | 1.53 | 2.00 | 2.91 | 3.40 | 4.12 | 3.26 | 14.40 | 25.17 | 14.01 | 7.96 | 6.25 | 4.83 | 5.96 |
1994 | 878 | 1245 | 775 | 558 | 455 | 402 | 378 | 2.19 | 1.47 | 1.92 | 2.87 | 3.22 | 3.86 | 2.94 | 13.51 | 24.02 | 14.47 | 8.24 | 6.63 | 5.19 | 6.61 |
1995 | 840 | 1020 | 800 | 546 | 457 | 400 | 375 | 1.95 | 1.65 | 1.87 | 2.47 | 2.96 | 3.69 | 2.87 | 14.85 | 19.33 | 15.14 | 9.46 | 7.22 | 5.42 | 6.75 |
1996 | 1020 | 978 | 747 | 568 | 460 | 407 | 378 | 2.16 | 1.90 | 2.40 | 2.58 | 3.16 | 4.10 | 3.39 | 14.78 | 16.44 | 11.38 | 9.23 | 6.80 | 4.92 | 5.73 |
1997 | 850 | 934 | 559 | 553 | 457 | 410 | 378 | 1.95 | 1.67 | 1.82 | 2.10 | 2.76 | 3.44 | 2.97 | 14.95 | 18.29 | 13.01 | 11.18 | 7.75 | 5.88 | 6.55 |
1998 | 797 | 906 | 604 | 491 | 410 | 378 | 358 | 2.14 | 1.84 | 1.94 | 2.26 | 2.96 | 3.83 | 3.15 | 13.19 | 16.38 | 12.68 | 9.81 | 6.85 | 5.08 | 6.00 |
1999 | 878 | 778 | 573 | 498 | 419 | 374 | 357 | 1.77 | 1.74 | 1.79 | 2.03 | 2.65 | 3.53 | 2.91 | 16.74 | 16.03 | 13.34 | 11.02 | 7.73 | 5.47 | 6.49 |
2000 | 905 | 845 | 605 | 471 | 428 | 362 | 352 | 2.46 | 1.92 | 1.65 | 1.92 | 2.56 | 3.36 | 2.87 | 12.23 | 15.16 | 14.93 | 11.31 | 8.07 | 5.67 | 6.54 |
2001 | 981 | 828 | 636 | 468 | 422 | 365 | 347 | 2.67 | 2.06 | 1.76 | 1.82 | 2.64 | 3.36 | 2.82 | 11.74 | 13.96 | 14.32 | 11.86 | 7.79 | 5.69 | 6.59 |
2002 | 853 | 955 | 649 | 455 | 421 | 356 | 333 | 3.21 | 2.25 | 1.88 | 2.16 | 2.74 | 3.56 | 3.31 | 9.10 | 13.73 | 13.57 | 9.87 | 7.49 | 5.30 | 5.51 |
2003 | 854 | 841 | 636 | 467 | 416 | 358 | 328 | 3.83 | 2.96 | 2.53 | 2.69 | 3.18 | 4.19 | 3.90 | 7.63 | 9.79 | 9.98 | 8.04 | 6.41 | 4.51 | 4.65 |
2004 | 910 | 909 | 666 | 443 | 432 | 362 | 343 | 3.75 | 2.93 | 3.09 | 2.91 | 3.32 | 4.48 | 4.01 | 8.04 | 10.30 | 8.34 | 7.22 | 6.27 | 4.25 | 4.62 |
2005 | 951 | 1095 | 706 | 453 | 441 | 361 | 345 | 3.64 | 3.11 | 3.21 | 3.11 | 3.54 | 4.89 | 4.45 | 8.48 | 10.63 | 8.27 | 6.85 | 5.93 | 3.88 | 4.17 |
2006 | 957 | 1273 | 722 | 457 | 450 | 364 | 353 | 4.07 | 2.82 | 3.07 | 3.43 | 3.61 | 4.66 | 4.30 | 7.59 | 12.64 | 8.76 | 6.24 | 5.88 | 4.09 | 4.36 |
2007 | 1100 | 1137 | 733 | 472 | 462 | 366 | 357 | 4.18 | 3.68 | 3.24 | 3.60 | 3.68 | 4.85 | 4.48 | 7.94 | 9.16 | 8.35 | 6.03 | 5.85 | 3.95 | 4.22 |
2008 | 1201 | 1166 | 727 | 491 | 464 | 367 | 358 | 3.95 | 3.36 | 3.38 | 3.79 | 3.89 | 4.82 | 4.53 | 8.77 | 10.15 | 7.98 | 5.84 | 5.54 | 3.97 | 4.18 |
2009 | 1225 | 1275 | 764 | 517 | 472 | 366 | 360 | 4.00 | 3.40 | 3.43 | 4.02 | 3.94 | 4.91 | 4.62 | 8.75 | 10.52 | 8.07 | 5.66 | 5.52 | 3.90 | 4.11 |
2010 | 1258 | 1358 | 763 | 521 | 468 | 371 | 363 | 4.12 | 3.39 | 3.53 | 4.09 | 4.09 | 5.09 | 4.76 | 8.61 | 10.87 | 7.82 | 5.58 | 5.29 | 3.78 | 4.00 |
2011 | 1299 | 1443 | 773 | 523 | 467 | 374 | 365 | 4.22 | 3.49 | 3.79 | 4.27 | 4.30 | 5.25 | 4.88 | 8.54 | 10.89 | 7.34 | 5.36 | 5.03 | 3.68 | 3.91 |
2012 | 1224 | 1466 | 845 | 525 | 468 | 377 | 368 | 4.34 | 3.51 | 3.64 | 4.35 | 4.57 | 5.41 | 4.94 | 8.06 | 10.90 | 7.99 | 5.26 | 4.74 | 3.59 | 3.88 |
2013 | 1261 | 1488 | 870 | 534 | 462 | 384 | 372 | 4.36 | 3.53 | 3.56 | 4.46 | 4.62 | 5.57 | 4.93 | 8.14 | 10.93 | 8.29 | 5.18 | 4.66 | 3.52 | 3.92 |
2014 | 1259 | 1480 | 873 | 547 | 471 | 384 | 372 | 4.36 | 3.91 | 3.77 | 4.52 | 4.61 | 5.52 | 5.11 | 8.14 | 9.84 | 7.83 | 5.17 | 4.71 | 3.55 | 3.78 |
2015 | 1280 | 1522 | 879 | 569 | 472 | 387 | 377 | 4.55 | 4.08 | 3.85 | 4.46 | 4.69 | 5.63 | 4.97 | 7.86 | 9.57 | 7.69 | 5.36 | 4.63 | 3.50 | 3.90 |
Table 2 Statistical parameters of the cross-sectional geometry of the main channel before and after the XLDR began operation |
Periods | Variables | Above HYK | HYK-JHT | JHT-GC | GC-SK | SK-AS | AS-LK | LK-LJ |
---|---|---|---|---|---|---|---|---|
1986-1999 | ${{y}_{{{B}^{0.5}}}}$ | 0.75 | 0.56 | 0.55 | 0.76 | 0.82 | 0.87 | 0.88 |
${{y}_{H}}$ | 1.03 | 0.98 | 0.92 | 0.72 | 0.73 | 0.78 | 0.74 | |
${{y}_{\xi }}$ | 0.73 | 0.57 | 0.60 | 1.06 | 1.13 | 1.12 | 1.19 | |
${{y}_{{{B}^{0.5}}}}\text{-}1$ | -0.25* | -0.44* | -0.45* | -0.24 | -0.18 | -0.13 | -0.12 | |
${{y}_{H}}\text{-}1$ | 0.03 | -0.02 | -0.08 | -0.28* | -0.27* | -0.22* | -0.26* | |
2000-2015 | ${{y}_{{{B}^{0.5}}}}$ | 1.21 | 1.40 | 1.24 | 1.07 | 1.06 | 1.02 | 1.03 |
${{y}_{H}}$ | 2.57 | 2.34 | 2.15 | 2.20 | 1.77 | 1.59 | 1.71 | |
${{y}_{\xi }}$ | 0.47 | 0.60 | 0.58 | 0.49 | 0.60 | 0.64 | 0.60 | |
${{y}_{{{B}^{0.5}}}}\text{-}1$ | 0.21 | 0.40 | 0.24 | 0.07 | 0.06 | 0.02 | 0.03 | |
${{y}_{H}}\text{-}1$ | 1.57* | 1.34* | 1.15* | 1.20* | 0.77* | 0.59* | 0.71* |
Note: The relative value y is equal to the ratio of the value at the end time yend to the value at the initial time yinitial, which was greater than the one implying increasing trend and less than the one implying a decreasing trend; the rate of change was equal to the relative value minus one, which was greater than zero, which implied an increasing trend, whereas a value of less than zero implied a decreasing trend. * is the indictor of the dominant variable, the larger changing rates of B0.5 and H. |
Figure 10 Adjustment of the typical cross-sectional profiles in the lower Yellow River |
Figure 11 Generalized models for the morphological adjustment of the lower Yellow River |
Figure 12 Relationships between the cross-sectional geomorphic coefficient of the main channel and the flow and sediment conditions of the lower Yellow River |
Figure 13 Relationships between morphological adjustment and cumulative erosion and sedimentation in the main channel per unit length of river of the lower Yellow RiverNote: Solid line indicates the continual siltation period 1986-1999, and the dashed line indicates the continual scouring period 2000-2015. |
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