The Cause and Statistical Analysis of the River Valley Contractions at the Xiluodu Hydropower Station, China

The Xiluodu Dam is a concrete double-curvature arch dam with a crest elevation of 610 m and a height of 285.5 m. Since the impoundment of the Xiluodu reservoir, remarkable river valley contractions (RVCs) have been observed upstream and downstream of the reservoir, potentially threatening the safety...

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Main Authors: Mingwei Li, Zhifang Zhou, Chao Zhuang, Yawen Xin, Meng Chen, Jian Wu
Format: Article
Language:English
Published: MDPI AG 2020-03-01
Series:Water
Subjects:
Online Access:https://www.mdpi.com/2073-4441/12/3/791
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spelling doaj-23599f756d2f4271bfb3a6bb1957fba42020-11-25T03:10:44ZengMDPI AGWater2073-44412020-03-0112379110.3390/w12030791w12030791The Cause and Statistical Analysis of the River Valley Contractions at the Xiluodu Hydropower Station, ChinaMingwei Li0Zhifang Zhou1Chao Zhuang2Yawen Xin3Meng Chen4Jian Wu5School of Earth Sciences and Engineering, Hohai University, Nanjing 210098, ChinaSchool of Earth Sciences and Engineering, Hohai University, Nanjing 210098, ChinaSchool of Earth Sciences and Engineering, Hohai University, Nanjing 210098, ChinaSchool of Earth Sciences and Engineering, Hohai University, Nanjing 210098, ChinaCollege of Hydrology and Water Resources, Hohai University, Nanjing 210098, ChinaSchool of Earth Sciences and Engineering, Hohai University, Nanjing 210098, ChinaThe Xiluodu Dam is a concrete double-curvature arch dam with a crest elevation of 610 m and a height of 285.5 m. Since the impoundment of the Xiluodu reservoir, remarkable river valley contractions (RVCs) have been observed upstream and downstream of the reservoir, potentially threatening the safety of the dam. However, the cause of these RVCs remains unclear. Based on an analysis of hydrogeological conditions, the RVCs were determined a result of the expansion of the aquifer, within which the effective stress decreased due to an increase in the hydraulic head after reservoir impoundment. Referring to the hydrostatic seasonal time (HST) model, a groundwater hydrostatic seasonal (GHS) model is proposed for simulating and predicting the development of the RVCs. Unlike the HST model, the GHS model can provide information on aquifer hydraulic diffusivity. The calibration results illustrate that the GHS model can accurately fit the observed RVCs data. The calculation results revealed that the RVCs were mainly affected by the hydraulic head of the confined aquifer, and that seasonal effects gave rise to less than 10% of the total RVCs. Finally, the development of RVCs were predicted using the GHS model. The prediction results demonstrated that the RVCs of most monitoring lines in the Xiluodu reservoir would gradually approach a convergence condition after 6 February 2021. Until the deadline of the prediction on 1 May 2035, there is still one monitoring line that has not reached a convergence condition (whose RVCs are 157.6 mm, and where the RVC growth rate will decrease to 0.005 mm/d by that time). Considering the large amount of RVCs, we think the safety of the dam requires closer consideration.https://www.mdpi.com/2073-4441/12/3/791river valley contractiondam safetystatistical modelshydraulic responses
collection DOAJ
language English
format Article
sources DOAJ
author Mingwei Li
Zhifang Zhou
Chao Zhuang
Yawen Xin
Meng Chen
Jian Wu
spellingShingle Mingwei Li
Zhifang Zhou
Chao Zhuang
Yawen Xin
Meng Chen
Jian Wu
The Cause and Statistical Analysis of the River Valley Contractions at the Xiluodu Hydropower Station, China
Water
river valley contraction
dam safety
statistical models
hydraulic responses
author_facet Mingwei Li
Zhifang Zhou
Chao Zhuang
Yawen Xin
Meng Chen
Jian Wu
author_sort Mingwei Li
title The Cause and Statistical Analysis of the River Valley Contractions at the Xiluodu Hydropower Station, China
title_short The Cause and Statistical Analysis of the River Valley Contractions at the Xiluodu Hydropower Station, China
title_full The Cause and Statistical Analysis of the River Valley Contractions at the Xiluodu Hydropower Station, China
title_fullStr The Cause and Statistical Analysis of the River Valley Contractions at the Xiluodu Hydropower Station, China
title_full_unstemmed The Cause and Statistical Analysis of the River Valley Contractions at the Xiluodu Hydropower Station, China
title_sort cause and statistical analysis of the river valley contractions at the xiluodu hydropower station, china
publisher MDPI AG
series Water
issn 2073-4441
publishDate 2020-03-01
description The Xiluodu Dam is a concrete double-curvature arch dam with a crest elevation of 610 m and a height of 285.5 m. Since the impoundment of the Xiluodu reservoir, remarkable river valley contractions (RVCs) have been observed upstream and downstream of the reservoir, potentially threatening the safety of the dam. However, the cause of these RVCs remains unclear. Based on an analysis of hydrogeological conditions, the RVCs were determined a result of the expansion of the aquifer, within which the effective stress decreased due to an increase in the hydraulic head after reservoir impoundment. Referring to the hydrostatic seasonal time (HST) model, a groundwater hydrostatic seasonal (GHS) model is proposed for simulating and predicting the development of the RVCs. Unlike the HST model, the GHS model can provide information on aquifer hydraulic diffusivity. The calibration results illustrate that the GHS model can accurately fit the observed RVCs data. The calculation results revealed that the RVCs were mainly affected by the hydraulic head of the confined aquifer, and that seasonal effects gave rise to less than 10% of the total RVCs. Finally, the development of RVCs were predicted using the GHS model. The prediction results demonstrated that the RVCs of most monitoring lines in the Xiluodu reservoir would gradually approach a convergence condition after 6 February 2021. Until the deadline of the prediction on 1 May 2035, there is still one monitoring line that has not reached a convergence condition (whose RVCs are 157.6 mm, and where the RVC growth rate will decrease to 0.005 mm/d by that time). Considering the large amount of RVCs, we think the safety of the dam requires closer consideration.
topic river valley contraction
dam safety
statistical models
hydraulic responses
url https://www.mdpi.com/2073-4441/12/3/791
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