Evaluation of Synergetic Development of Water and Land Resources Based on a Coupling Coordination Degree Model

The interaction between water and land resources (WALRs) has been further enhanced with the development of human production activities. Evaluating the synergetic development (SD) level of WALRs is conducive to discovering the weakness of comprehensive utilization of resources and promoting sustainable development. However, previous studies did not clearly elucidate the effects of the synergetic development between WALRs (SD-WALRs). For evaluation methods, the impact of various subsystem development levels on the whole system is often ignored due to its unclear definition. Therefore, in this research, the concept of the SD-WALRs was defined based on synergetic theory. By using the "Driving Force-Pressure-State-Impact-Response" (DPSIR) model, comprehensive evaluation index systems of WALR development were established. The index systems were regarded as efficacy functions of the coupling coordination degree (CCD) model, and the evaluation model of the SD-WALR level was constructed based on it. Taking Luoyang City as an example, using the latest 10 years (2010-2019) with available data as the study period, the results showed that the value of the SD degree increased from 0.609 to 0.789 during the study period, which reached the level of intermediate synergetic development. In general, the development of WALRs showed a positive trend from "high coupling but low synergetic development" to "high synergetic development".