A Comment on Chinese Policies to Avoid Negative Impacts on River Ecosystems by Hydropower Projects
2. Description of the Two Standards for Development of Water Use Projects
3. Comparison Analysis of the Two Standards for Development of Water Use Projects
3.1. Basic Principles
3.2. Components and Definition of Terms
3.3. Analysis of the Calculation Process
- is the environmental flows (m3/s);
- is the aquatic ecological flow needs (m3/s);
- is the environmental flow (m3/s) which is considered by the water quality and water environmental functions (shipping);
- is the water required for landscape and ecology (m3/s);
- is the estuary environmental flow needs (m3/s);
- is the river riparian wetland flow needs (m3/s);
- is the in-stream groundwater recharge needs (m3/s).
3.4. Recommended Methods
4. Weaknesses and Recommendations
- Because the standards come from two different authorities, the definition of related terms is not clear. This may lead to misunderstandings during implementation. Water managers may have errors in textual understanding when using the standards. More seriously, due to differences in understanding, there may be increased misunderstandings between stakeholders.
- In the process of data collection, both standards mention the collection of watershed hydrology, river topography, aquatic ecology, relevant planning and research results. Although the process of evaluating environmental flows in the standards is scientific, it is difficult to evaluate and implement environmental flows according to the requirements of the standards considering the actual situation.
- Both standards classify environmental flows into base environmental flows (minimum flows) and targeted environmental flows (variable environmental flows). The purpose of this consideration is to rationally use water resources and then create economic value under the premise of protecting ecosystems. How to trade-off the relationship between environment value and the economic value? There is no operational suggestion for water manager.
- In the specific calculation process, both standards recommend a variety of calculation methods. The standard also clarifies how to choose the method for base environmental flow and targeted environmental flow. However, most of the methods are hydrological methods, and the results of hydrological calculations often lack consideration of ecological processes. Additionally, most of the rivers lack sufficient data, which can impede the implementation of environmental flows.
- In the ecological process, both standards recommend habitat analysis methods and consider the relationship between hydrological-ecological responses. However, in the actual process, only the large watersheds in China currently have relevant ecological data, which brings difficulties to river managers. In CEHP, it is recommended that water managers consider the hydrological process of different fish breeding seasons. Due to the difficulty of data collection and long cycle monitoring, this is not feasible in practical work.
- During the process of verifying the rationality of the results, both standards emphasize the need to use multiple methods for calculations and comparison of results to determine a reasonable hydrological process. This is positive but undoubtedly increases the cost of river management.
- A reasonable range of parameters is given in the two standards, except for habitat analysis methods. Because habitat analysis methods are always based on a rigorous aquatic ecology survey and expert advice, a reasonable range of habitat parameters can be determined. Due to the many remaining problems in the history of watershed management, the habitat analysis method is not available in most rivers in China. Moreover, much upfront capital investment is needed which cannot be used in medium or small river.
- The unknown long-term change of climate and hydrological conditions will bring unpredictable impacts on the ecosystem, such as the invasion of non-native species caused by the change of environmental conditions (rainfall and temperature under changing conditions) that lead to the failure of traditional calculation methods (provided in the two standards) in practical water resources management.
- Most of the environmental flow calculation methods recommended in the two standards are from foreign countries, and the portability and preconditons for some of them needs further research.
Conflicts of Interest
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|Issuing Authority||Guideline||Related Content|
|Technical guide for environmental impact assessment of river ecological flow, cold water, and fish passage facilities for water conservation construction projects (trial) EIA Letter (2006) No.4||The lower limit of the ecological base flow should not be less than 10% of the average annual natural runoff.|
|Ministry of Water Resources||Guidelines for assessment of rivers and lakes eco-water demands (SL/Z 479-2010)||Ecological base flow generally takes the minimum monthly average flow of 90% of the control nodes; the minimum ecosystems water demand in the river, and the average annual runoff of the control nodes in the north is generally 10–20%, 20–30% in the south.|
|Ministry of Water Resources||Technical specification for the analysis of supply and demand balance of water resources (SL 429-2008)||The eco-hydrological elements of water project planning and design should consider the ecological base flow and sensitive ecological water demand at the river basin scale, river corridor scale and river scale, and further standardize.|
|Issued authority||Ministry of Water Resources of the People’s Republic of China||National Energy Administration of China|
|Purpose||Technical requirements, basic procedures and calculation methods for regulating the ecosystems of rivers and lakes in order to protect and restore the ecosystems of rivers and lakes||In order to standardize the conditions, contents and methods for calculating the ecological flow of hydropower projects 1, and to unify the technical requirements, this specification is formulated.|
|Object||It is applicable to the ecosystems water demand calculation and water project 2 planning, design and management of water environment integration and professional planning for watershed and regional ecosystems water demand calculation||It is suitable for the analysis and calculation of ecological flow of hydropower projects 1.|
|In-stream environmental flow||River, Lake, Swamp||River, Riparian wetland, Scenery, Estuary, In-stream groundwater,|
|Off-stream environmental flow||Urban green space|
Rivers, lakes and marshes replenish water
|Riparian wetland, Scenery, Estuary|
|SERL||In-stream environmental flow||In order to maintain the ecological and environmental protection goals of rivers, lakes and marshes.|
|In-stream fundamental environmental flow||The minimum amount of water in the river.|
|In-stream targeted environmental flow||The amount of water retained in the river to maintain the ecological and environmental functions.|
|Off-stream environmental flow||Artificial water supply in order to achieve certain ecological goals.|
|CEHP||Ecological flow||In order to ensure the flow for ecosystem in the downstream reach of hydropower project.|
|Aquatic ecological flow needs||Suitable flow to guarantee the basic stability of the aquatic ecosystem in the downstream sections of hydropower projects.|
|Aquatic ecological base flow||Minimum flow to guarantee the basic quality of aquatic habitat in the downstream sections of hydropower projects.|
|SERL||In-stream fundamental environmental flow||Qp 1, 7Q10, The most dry month method (MDM) 2, Flow duration curve method, Tennant, Frequency curve method, Wetted perimeter method, Habitat analysis method, River bed morphology analysis method.|
|In-stream targeted environmental flow||Tennant, Frequency curve method, Habitat analysis method.|
|CEHP||Aquatic ecological flow needs||Wetted perimeter method, R2-CROSS method, Eco-hydraulic method, Habitat analysis method, Tennant, 7Q10.|
|Aquatic ecological base flow||Wetted perimeter method, R2-CROSS method, Eco-hydraulic method, Tennant, 7Q10.|
|Base Flow||Suitable Flow||Base Flow||Suitable Flow||Base Flow||Suitable Flow|
|L 2||Nor 5||10–20||40–50||15–25||45–55||≥25||≥60|
|M 3||Nor 5||10–15||40–50||10–25||40–55||≥25||≥55|
|S 4||Nor 5||5–10||40–45||10–20||40–50||≥20||≥50|
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Wu, M.; Chen, A.; Zhang, X.; McClain, M.E. A Comment on Chinese Policies to Avoid Negative Impacts on River Ecosystems by Hydropower Projects. Water 2020, 12, 869. https://doi.org/10.3390/w12030869
Wu M, Chen A, Zhang X, McClain ME. A Comment on Chinese Policies to Avoid Negative Impacts on River Ecosystems by Hydropower Projects. Water. 2020; 12(3):869. https://doi.org/10.3390/w12030869Chicago/Turabian Style
Wu, Miao, Ang Chen, Xingnan Zhang, and Michael E. McClain. 2020. "A Comment on Chinese Policies to Avoid Negative Impacts on River Ecosystems by Hydropower Projects" Water 12, no. 3: 869. https://doi.org/10.3390/w12030869