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Wang Z, Feng J, He T, Yang J, Wan H, Yuan Y, Li R. Study on the habitat evolution after dam removal in a habitat-alternative tributary of large hydropower station. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 360:121155. [PMID: 38761624 DOI: 10.1016/j.jenvman.2024.121155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 04/27/2024] [Accepted: 05/10/2024] [Indexed: 05/20/2024]
Abstract
The establishment of large hydropower stations in the main stream poses a threat to fish habitats. Selecting suitable tributaries as alternative habitats is a practical measure for ecological environment protection during large hydropower station's construction. The small dams constructed on certain tributaries need to be removed in order to restore river connectivity. The removal of dams will activate hydro-sedimentary dynamics and change the original habitat in terms of topography and hydrodynamics. To explore the evolution of fish habitats following the removal of small dams, a dam-removed reach of a habitat-alternative tributary was selected as the research object, and the model of water-sediment transport and riverbed evolution in strongly disturbed dam-removed reaches and the model of fish habitat suitability evaluation were established. The key parameters calibration and model verification were completed by field monitoring results. The simulation results showed dramatic evolution in the reservoir riverbed in the initial stage after dam removal and during the high discharge period. One year after dam removal, there was a noticeable 4.0 m incision in front of the dam, along with a decrease in channel slope at the dam site from about 4.8% to approximately 1.5%. Downstream of the dam, alterations to the riverbed were mainly concentrated near the dam, and sedimentary bodies with a height of around 2.0 m have formed on the left bank following the high discharge period. The fish habitat in most areas of the dam-removed reach was suitable, except for the downstream high-velocity area. To compare the evolution process of fish habitat under two dam removal periods in wet and dry seasons, two dam removal schemes were implemented in March and June. The results showed that the riverbed evolved more gradually in the March scheme, creating a larger and continuous suitable habitat for fish. Therefore, the March scheme was recommended. By revealing the evolutionary pattern of fish habitat after dam removal, this research provides a reliable model for assessing and restoring habitats in dam-removed reaches, and enjoys significant implications for protecting river ecology in hydropower development reaches.
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Affiliation(s)
- Zhenhua Wang
- State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, Sichuan, 610065, China
| | - Jingjie Feng
- State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, Sichuan, 610065, China.
| | - Tao He
- Power China Chengdu Engineering Corporation Limited, Chengdu, Sichuan, 611130, China
| | - Jiuxian Yang
- Power China Chengdu Engineering Corporation Limited, Chengdu, Sichuan, 611130, China
| | - Hang Wan
- Research Centre of Ecology & Environment for Coastal Area and Deep Sea, Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, 511458, China.
| | - Yuliang Yuan
- State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, Sichuan, 610065, China
| | - Ran Li
- State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, Sichuan, 610065, China
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Zhang P, Liu Q, Wang Y, Zhu DZ, Liang R, Qin L, Li R, Ji Q, Li K. River habitat assessment and restoration in high dam flood discharge systems with total dissolved gas supersaturation. WATER RESEARCH 2022; 221:118833. [PMID: 35841786 DOI: 10.1016/j.watres.2022.118833] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 06/27/2022] [Accepted: 07/06/2022] [Indexed: 06/15/2023]
Abstract
The success of river habitat restoration relies on accurate assessment proxies. However, determining how to quantitatively assess the impact of multiple stressors during flood discharge from high dams in riverine ecosystems and where and how to implement more reliable recovery interventions remain challenges. Here, we developed a bottom-up mechanistic framework for assessing the effects of total dissolved gas supersaturation (TDGS) and hydrodynamics on fish habitat quality and applied it to the downstream river reach of the Xiangjiaba Dam in Southwest China. The results showed that the available habitat area of river sturgeon was the smallest, while Chinese sucker had the largest available habitat area among the three target species under all discharge scenarios. Although the TDGS levels were evenly mixed laterally, the habitat suitability index indicated that the suitable habitats were primarily within both sides of the river reach under all scenarios, which is contrary to findings based on the traditional TDGS risk assessment model. The traditional TDGS risk assessment model overestimates the impact of dams on habitats. This divergence reflected the sensitivity of the habitat assessment to fish habitat preferences, fish tolerance to TDGS and the biological response of fish under TDGS. Additionally, the priority areas for restoration can be identified by habitat suitability index with lower values. We simulated twenty-four schemes and found that interventions such as stone groups, ecological spur dike, water-retaining weir and river dredging can enhance habitat suitability for fish species under multiple stressors, providing novel insights into where and how to mitigate the impact of TDGS. Our findings offer a transferable framework for the quantitative evaluation of fish habitat and implementation of restoration management during dam flood discharge periods, thus providing a new perspective for biodiversity conservation and habitat restoration in dam-regulated rivers with TDGS around the world.
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Affiliation(s)
- Peng Zhang
- State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China
| | - Qingyuan Liu
- State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China
| | - Yuanming Wang
- State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China.
| | - David Z Zhu
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada
| | - Ruifeng Liang
- State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China
| | - Leilei Qin
- China Three Gorges Projects Development Co., Ltd., Chengdu 610042, China
| | - Ran Li
- State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China
| | - Qianfeng Ji
- State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China
| | - Kefeng Li
- State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China
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Tonina D, McKean JA, Isaak D, Benjankar RM, Tang C, Chen Q. Climate Change Shrinks and Fragments Salmon Habitats in a Snow-Dependent Region. GEOPHYSICAL RESEARCH LETTERS 2022; 49:1-10. [PMID: 35928231 PMCID: PMC9344378 DOI: 10.1029/2022gl098552] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 05/17/2022] [Indexed: 06/01/2023]
Abstract
Climate change threatens biodiversity through global alteration of habitats, but efficient conservation responses are often hindered by imprecise downscaling of impacts. Besides thermal effects, warming also drives important ancillary environmental changes, such as when river hydrology evolves in response to climate forcing. Earlier snowmelt runoff and summer flow declines are broadly manifested in snow-dependent regions and relevant to socioeconomically important cold-water fishes. Here, we mechanistically quantify how climate-induced summer flow declines during historical and future periods cause complex local changes in Chinook salmon (Oncorhynchus tshawytscha) habitats for juveniles and spawning adults. Changes consisted of large reductions in useable habitat area and connectivity between the main channel and adjacent off-channel habitats. These reductions decrease the capacity of freshwater habitats to support historical salmon abundances and could pose risks to population persistence in some areas.
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Affiliation(s)
- Daniele Tonina
- Center for Ecohydraulics Research, University of Idaho, Boise, ID, USA
| | - James A McKean
- Rocky Mountain Research Station, Aquatic Laboratory, Boise, ID, USA
| | - Daniel Isaak
- Rocky Mountain Research Station, Aquatic Laboratory, Boise, ID, USA
| | | | - Chunling Tang
- US Environmental Protection Agency, Washington, DC, WA, USA
| | - Qiuwen Chen
- Nanjing Hydraulics Research Institute, Nanjing, China
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