关键词: 水土保持功能分区, 投资评价法, 功能匹配性, 生态清洁小流域建设, 海南岛

Abstract:

The zoning of soil and water conservation functions for small watersheds is the basis for implementing classified management, consolidating the benefits of control measures, and ensuring local and nationwide sustainable development. Most of the studies on function zoning research mainly consider the social, resource, and economic conditions of small watersheds, and seldom consider the requirements of the development and main function plans at the upper level (such as provincial-level plans). Since 2019, the Ministry of Ecology and Environment of the P. R. China has carried out the works for compilation of ecological protection red lines, environmental quality bottom lines, resource utilization upper lines, and ecological environment access lists (“three lines and one list”) throughout the country and the Ministry of Natural Resources has carried out the demarcation of the “three zones” (urban space, agriculture space ecological space) and “three lines” (Cultivated land and permanent basic farmland protection red line, Ecological protection red line, Urban development boundary) and the practice of “territorial and spatial planning” also, up to the present, the national land use control system has been established. In February 2023, the Ministries of Water Resources and Agriculture and Rural Affairs, the National Forestry, Grassland Admiration and the National Administration for Rural Revitalization jointly issued the “the Guidance for enhance the Eco-environment friendly small watersheds development”, and proposed to build different small watershed industrial complexes, such as the water source protection, the ecological tourism, the harmonious and livable, recreation, health and wellness and green industry according to local conditions. In October 2023, the national water standard “Technical Specifications for the Construction of Eco-environment friendly small watersheds (EFSWs)” (SL/T 534—2023) was issued and implemented, and the development conditions for the five types of EFSW were proposed. The above plans, guidance, and standards provide a theoretical basis for the classification of EFSW in this new era. Since 2016, the Hainan Province has vigorously constructed EFSWs. After years of practice, remarkable achievements have been made in the construction of EFSWs in the Hainan Province. By the end of 2020-2023, 42 EFSWs were implemented, and EFSWs construction has entered a fast path. However, it is unclear whether the constructed small watersheds meet the requirements of land-use control (three zones and three lines), environmental protection, and soil and water conservation in the new era. Whether the measures and their functions match the needs of the main functional zone, soil and water conservation zone, and other related plans of Hainan Island are questions that need to be explored and clarified. Therefore, based on the need for land use control and soil and water conservation in Hainan Province, this study explores the matching of the control measures and functions of EFSWs with the goals of the functional zone on Hainan Island to improve the benefits of small watershed investment and realize small watershed integrated system governance solutions for the community of life of the mountains, rivers, forests, farmlands, lakes, grasslands, and deserts. A small watershed functional zoning method was proposed based on Territorial and Spatial Planning, Land Environment Control Planning and Soil and Water Conservation Planning of Hainan Province and the GIS spatial overlay technology was used to divide the function zone. 42 EFSWs built on Hainan Island from 2020 to 2023 were considered as research objects, and a matching evaluation model was established to assess how the control measures of EFSWs meet the requirements of different function zones. The results showed that 1) the construction of small watersheds on Hainan Island can be divided into five functional zones: major green agricultural products (GP), water conservation (WC), ecological protection (EP), harmonious and livable (HL), and recreation, health, and wellness zones (RH). In which, the area of GP function zone is the largest, which is 12789.42 km², accounting for 37.2% of Hainan Island, followed by WC (25.9%), EP (16.6%), RH (10.5%) and HL (9.9%). Improving agricultural infrastructure conditions is the main goal of small watershed construction in the GP zones. Management measures included farmland road construction, soil conservation tillage, terraces, slope drainage systems, and gully head protection measures. 2) Twenty small watersheds are distributed in the GP zone. However, there are certain deviations between the measured arrangement and investment to match the function requirements of the GP zone. Among them, the matching level of 16 watersheds is belong to “medium” or below (matching index≤0.4); the matching level of 22 small watersheds in other function zones is relatively higher. 3) Overall, the matching level of 25 small watersheds in Hainan Island is belong to “medium” or above (matching index>0.4), accounting for 59.5%, and the matching level of 17 watersheds is low (matching index≤0.4), accounting for 40.5%, and 16 small watersheds are concentrated in the GP zones. Therefore, in the future construction of EFSWs on Hainan Island, attention should be paid to the GP zone and the investment proportion of important measures to improve agricultural infrastructure construction should be increased. It will be better to meet the requirements of policies, land use control, and environmental protection in the new era, and the functions of control measures can provide more ecological service values in the long term. This study provides theoretical references and practical methods for function zoning and small-watershed construction nationwide.

Key words: function zoning of soil and water conservation, investment evaluation method, function matching level, eco-environment friendly small watersheds construction, Hainan Island