Urban Water Ecosystem Health Evaluation Based on the Improved Fuzzy Matter‐Element Extension Assessment Model: Case Study from Zhengzhou City, China

Abstract

The urban water ecosystem is a core foundation for the urban construction of ecological civilization. Ecosystem health is directly related to the economic development of the region and the quality of urban residents’ lives. Evaluating the health state of an urban water ecosystem is an important prerequisite for the construction of an ecologically civilized city. This study used Zhengzhou City in China as research area. Firstly, a Pressure-State-Response (PSR) model was used to construct an urban water ecosystem evaluation index system. Secondly, after analyzing the deficiency of traditional fuzzy matter-element extension model in urban water ecosystem health assessment, an improved fuzzy matter-element extension assessment model (FMEAM) was constructed by introducing the variable weight theory. Finally, using the proposed model above and the data from 2007 to 2016, this study evaluated the water ecosystem health status of Zhengzhou based on water ecosystem health integrated index (WHI). The results showed that the state of the urban water ecosystem in Zhengzhou generally improved during the study period. However, the overall level still remained low and retained an unhealthy state throughout the timeframe. The pressure on the Zhengzhou water ecosystem mainly originates from the increasing urbanization rate, the increased consumption of ecological environmental resources, and household water. Corresponding countermeasures in Zhengzhou have achieved certain results, and the health of the state’s subsystem and response subsystem has improved. However, it remains necessary to further strengthen the protection of the ecological environment, particularly with respect to water resources.

Urban River Health Analysis of the Jialu River in Zhengzhou City Using the Improved Fuzzy Matter-Element Extension Model

“…where k ij is the relation degree of the index value x i in j-th year. In accordance with previous research on the fuzzy matter-element extension model [6,51], a i represents the new threshold value between "very sick" and "sick", and b i represents the new threshold value between "healthy" and "sub-healthy" in Table 2, respectively.…”

“…The fuzzy matter-element extension model, combined with fuzzy matter-element theory and with an extension set, are used to analyze the possibility and regularity of an object. As a formal and quantitative solution, the matter-element extension model is often used in multi-index assessments and to solve incompatible complex problems [50,51]. Urban river health is a complex and relative fuzzy concept, and the classification standards vary according to the different evaluation indexes.…”

“…According to the matter-element extension theory [6,50,51], uRHI can be obtained from the entropy weight of the index and the relation degree matrix. The uRHI of the urban river health assessment in the present study was calculated by the following formula:…”

Evaluating the Health of an Urban River Combining DPSIR Framework and an Improved Fuzzy Matter-Element Extension Model: a Case Study from the Jinshui River

“…The fuzzy matter-element analysis combines extenics with fuzzy mathematics to solve the incompatible complex problems in multi-indicator assessment [17]. The FMEE method is often used to assess environmental quality [42][43]. Urban river health is a complex and relative fuzzy concept, and the classification standards of the evaluation indicators are not the same.…”

“…An urban river can be assessed using the improved FMEE extension model. Steps of this model are as follows [17,[42][43]: (1) Calculate the indicator weight using the entropy method (a) Non-dimensionalization data processing Given the evaluation standards of indicators are inconsistent, it is necessary to convert the indicator values to dimensionless values, using the following normalization formula:…”