Keywords

1 Introduction

China’s watershed development has a long history, wide scope and high intensity, and the impact and consequences on the watershed ecosystem are extremely significant (Liu et al. 2021). Scientific planning of watershed development and strengthening ecological protection has become an inevitable choice to deepen the construction of watershed ecological civilization (Huang et al. 2018). As a legal environmental management tool, environmental impact assessment (EIA) plays an important role in coordinating socio-economic development and ecological protection in China’s watersheds. Domestic and international studies have shown that evaluating alternatives is a key step to improve the planning objectives and successfully implement the planning EIA (Huang et al. 2020). However, how to reasonably assess the ecological and environmental impacts of planning alternatives has been a prominent weakness in China’s watershed planning EIA.

As China’s latest environmental management policy of “three lines and one list” (TLOL) is a framework based on the threshold management of ecology, environment and resources (MEE 2016). It is composed of an ecological conservation red line, an environmental quality bottom line, a resource utilization upper limit, and an environmental permit list. With an aim of improving the quality of the environment, TLOL imposes explicit and rigid environmental constraints on economic development and resource utilization. Obviously, TLOL is in line with the watershed planning EIA of principle of weighing and maximizing the synergy between environmental governance requirements and development goals (Martínez-Bravo et al. 2019). Therefore, TLOL can provide a comprehensive framework for evaluating alternatives of watershed planning in EIA.

We also adopted Rapid impact assessment matrix (RIAM) to assess alternatives under the TLOL framework in this paper. The RIAM method is a semi-quantitative assessment method that combines standardized assessment scales with index calculation (Marcos et al. 2022). It has been regarded as an effective means to rapidly analyze the environmental impact of projects in EIA. In planning EIA studies, this method has been used for screening alternative of rehabilitation in small-scale water systems (Shakib-Manesh et al. 2014), evaluating urban industrial development planning (Phillips 2015), and selecting new site for municipal solid waste disposal (Seshagiri et al. 2016).

The remainder of this paper is organized as follows. Section 2 proposes an assessment indicator system amd RIAM method would be used to evaluate alternatives. Meanwhile, this section introduces an overview of development of Jinjiang watershed, which is used as our case study, and develops a set of alternatives for consideration. Section 3 presents results and discussion. Section 4 gives conclusion and implications.

2 Materials and Methods

2.1 Building up an Assessment Indicator System

The TLOL set ecological environment constraints on watershed development from three dimensions: ecological protection red line, environmental quality bottom line and resource utilization upper line. In this paper, the structural characteristics of the commonly used RIAM evaluation index system were considered, and four index sets were divided into ecological protection (EP), environmental improvement (EI), resource utilization (RU), and social economy (SE). Meanwhile, 34 specific indicators were selected as secondary indicators of this evaluation (Table 1).

Table 1. The indicator system for evaluating environmental impacts of alternatives of watershed development planning
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2.2 Assessing Alternatives by the RIAM Method

The assessment criteria that are usually employed in the RIAM approach are: importance of the condition (A1), magnitude of change/effect (A2), permanence (B1), reversibility (B2), and cumulative (B3). Against these criteria, both positive and negative impacts brought about by each alternative are assessed based on the environmental, ecological, societal, and economic indicators. Scores based on these assessments are calculated as follows:

$$ ({\text{A}}1) \times ({\text{A}}2) = ({\text{AT}}) $$
(1)
$$ ({\text{B1}}) + ({\text{B2}}) + ({\text{B3}}) = ({\text{BT}}) $$
(2)
$$ ({\text{AT}}) \times ({\text{BT}}) = ({\text{BS}}) $$
(3)

The final result in this series of calculations, (ES), is the evaluated score for a given indicator. A1 and A2 are criteria that are important for the condition; for this reason a multiplication is required in Eq. (3). B1, B2, and B3 are criteria that are of value to the situation; to ensure that their collective importance is taken into account, addition is the appropriate operation in Eq. (4) (Pastakia and Jensen 1998).

To avoid placing undo significance on a specific number, a more efficacious system of assessment has been developed with the aid of range bands. Eleven range bands are usually employed: −E, −D, −C, −B, −A, N, +A, +B, +C, + D and +E. An ES score of 0 implies that no impact or change occurs; in this case, the score falls in the range band designated as N. The range bands from −A to −E provide descriptive measures ranging from slightly negative to major negative impacts; those from +A to +E provide descriptive measures ranging from slightly positive impacts to major positive impacts (Table 2). Moving a step beyond the standard RIAM process, we have formulated an integrated environmental score (IES). Simply put, the IES for an alternative is summation of the ES values derived from the four indicator categories. It is calculated as follows:

$$ {\text{IES}} = \sum\limits_{i = 1}^{4} {{\text{(W}}_{c,i} \times {\text{ES}}_{c,i} } ) $$
(4)

where i represents an indicator category (PC, BE, SC, or EO) and Wc,i and ESc,i are the assigned weight and the ES value, respectively, for category i. In this equation, ESc,i is derived from the formula:

$$ {\text{ES}}_{c,i} = \sum\limits_{j}^{{}} {{\text{(W}}_{j} {\text{ES}}_{j} } ) $$
(5)

where Wj and ESj represent the weight and environmental score (ES), respectively, for indicator j in category i.

Table 2. The assessment criteria of RIAM
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By developing the impact level description system, the range of scores from −108 to 108 was divided into 11 environmental impact level segments, and the intervals where the scores of each index and the total scores of each alternative were located and the corresponding impact levels were found to obtain the ecological impact of the alternative on a certain index and on the whole watershed (Table 3).

2.3 Overview of the Jinjiang Watershed

Jinjiang watershed is located in the southeast coast of Fujian Province, bordering the Min River and Jiulong River. The administrative region includes the districts of Jinjiang, Nan’an, Anxi, Yongchun, Licheng, Fengze, and Luojiang. Jinjiang watershed covers an area of 5629 km2, river length of 182 km, average river slope drop of 1.9%. Jinjiang watershed has experienced a rapid development of socio-economic, accounted for 1/4 of Fujian Province’s GDP in 2016, and the area is known as the core of the Southern Fujian Golden Triangle (Yang et al. 2015).

The rapid development has led to ecological and environmental problems in the area of Jinjiang watershed. The utilization rate of water resources has reached 48.2%, which is higher than the average level in China. According to current trends, it is expected that the rate of hydro energy development in the basin can reach 60% by 2030 and cause a shortage of 1.33 billion m3 of water supply (accounting for 37% of the total water demand) (Ma et al. 2015). Small hydropower is intensively developed in the Jinjiang watershed, especially the diversion type hydropower with less than 1000kw accounts for more than 85%, and most of them are not equipped with facilities for fish crossing and maintaining the ecological downstream flow. It has resulted in severe dewatering and a significant reduction in the pollution carrying capacity of the downstream reaches. It has resulted in severe dewatering and a significant reduction in the pollution carrying capacity of the downstream reaches. It also leads to the disappearance of aquatic organisms such as the original migratory fish in the basin. Optimizing the layout of hydropower development, improving the efficiency of water resources, controlling the total amount of water resources utilization, and strengthening ecological and environmental management are core issues of the sustainable development of the Jinjiang watershed.

Table 3. Conversions of the environmental scores to the range bands in RIAM
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2.4 Developing Alternatives of Jinjiang Watershed Planning

Due to the serious shortage of water resources and the over-exploitation of hydropower have seriously affected the ecological environment security of Jinjiang watershed and become the key restrictions of regional social and economic development. It is the top priorities to improve environmental sustainability of Jinjiang watershed development and promote trade-off synergy between watershed development activities and environmental protection.

To prevent the environmental problems mainly aggravated by irrational resource exploitation and watershed development activities, a new development plan of Jinjiang watershed was constructed.The planning and control objectives focus on solving the three most prominent problems of water resources utilization, hydropower development and ecological environmental protection in the Jinjiang watershed, and propose planning measures. Ecological environmental protection objectives are proposed in terms of water environment quality, ecological function improvement and ecological spatial integrity of the watershed; water resources development control objectives are clarified by controlling water resources development utilization rate and water saving efficiency; water energy development control objectives are proposed by water energy development access conditions and small hydropower cleanup. Based on the three control objectives, the Jinjiang watershed development plan proposes six alternatives (Table 4), combined with the requirements of the TLOL.

Table 4. Alternatives in the development planning of Jinjiang watershed
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3 Results and Discussion

The assessment results of ES for alternatives are shown in Fig. 1. Results show that Alternative 1 would have negative impact on the four categories of “resource use (RU)”, “environmental improvement (EI)”, “ecological protection (EP)”, and “social economy (SE)”, which is significantly worse than the remaining alternatives. Alternative 2 would has a moderate positive impact on RU and EI, and a negative impact on EP. Alternative 3 would has no impact on RU, EI and EP, and a positive impact on SE. Alternative 4 would has a positive impact on all indicators of EI, and a positive impact on RU and SE, and a moderate negative impact on EP. Alternative 5 would has no impact on all four categories of indicators, with positive impact on EP and SE. Alternative 6 would has positive impacts on RU, EI, and EP, and no impact on SE.

Fig. 1.
figure 1

The evaluating results of planning alternatives by RIAM.

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Comprehensive assessment was conducted on the four index sets of RU, EI, EP and SE, and the results of IES are shown in Table 5. By comparing the results of the six alternatives, Alternative 2 has the best performance and Alternative 2 has the worst performance. .

Alternative 2 has a positive impact on most of the indicators, and the IES performance is significantly better than the remaining alternatives, so it can be judged that the implementation of Alternative 2 has a positive impact on EI, EP, RU and SE of the Jinjiang watershed. From the perspective of watershed planning EIA, the implementation of Alternative 2 is more advantageous in optimizing water resources allocation, ensuring ecological water use of downstream, and strictly controlling hydropower development. Therefore, Alternative 2 can be recommended for detailed assessment.

Table 5. IESs of the planning alternatives
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4 Conclusion

This paper integrates the requirements of the “three lines and one list” environmental governance with the traditional RIAM method, and constructs the TLOL-RIAM method with an indicator system for watershed planning EIA including four dimensions of RU, EI, EP, and SE. Meanwhile, the traditional RIAM method is improved by introducing the Integrated Environmental Evaluation Score (IES). Applying the constructed method to a planning EIA of Jinjiang watershed in China as a case study. The results shows that, the IES performance of Alternative 2 is the best, and recommended it as the optimal one. Focusing on the measures of Alternative 2, the EIA proposed some suggestions to planning decision makers, including the implementation of water diversion projects in the watershed, strengthening the management of water resources dispatching, and controlling the scale of small hydropower.

The application case of the Jinjiang watershed shows that, the TLOL-RIAM method can help EIA to make a preliminary assessment of alternatives from a comprehensive perspective in the early stage, and propose timely optimization suggestions for planning. The finding in this study is expected to provide a useful reference for the study of watershed planning EIA in China.