陕北—湖北±800kV输电线路工程水土流失特征及其综合治理

输电线路作为路径长、跨度大的典型线型工程,在生态环境脆弱的丘陵地貌、山地地貌等山丘区进行建设,会破坏该区环境,加剧水土流失。为顺应当前国家生态文明建设新形势,以沿线涉及黄土丘陵地貌、山地地貌和平原地貌的陕北—湖北±800 kV特高压输电线路工程为例,通过野外调查和测钎法监测水土流失,对其水土流失特征、强度及其治理体系进行探讨。结果表明:(1)特高压输电线路工程水土流失具有点状线型分布特征; 其工程空间跨度大,侵蚀环境差异显著,侵蚀类型多且复杂。(2)输电线路工程在黄土丘陵地貌的土壤侵蚀模数〔12 000～25 000 t/(km²·a)〕明显高于山地地貌〔3 600～9 500 t/(km²·a)〕和平原地貌〔950～2 000 t/(km²·a)〕,是该工程重点土壤侵蚀防治区。(3)站区和塔基区是输电线工程造成最大土壤侵蚀量的水土流失单元,其土壤侵蚀量分别为27 267 t和37 478 t,应为水土流失重点防治单元。(4)在水土流失治理的工程措施基础上,融入近自然治理思想,优先选择乡土草、灌、树种,以此集成针对山丘典型生态环境脆弱区的输电线路水土流失综合治理体系。研究结果可为输电线路工程水土流失防治提供理论依据和决策支持。

Characteristics of Soil Erosion and Comprehensive Control of Shanbei-Hubei ±800 kV Transmission Line Project

China is a mountainous country, and transmission lines, as a typical linear project with long paths and large spans, are inevitably constructed in loess hills and hilly areas where the ecological environments are fragile, which destroys the environment and exacerbates soil erosion in this area. In order to comply with the current new situation of national ecological civilization construction, we took the northern Shaanxi-Hubei ±800 kV UHV transmission line project involving the loess hilly and gully area, hilly area and plain area as an example, and monitored the water and soil through field surveys and drilling methods. Erosion, the characteristics and intensity of soil erosion and its governance system were discussed. The results show that:(1)the soil erosion of the UHV transmission line project has the characteristics of point-like linear distribution; its engineering space span is large, the erosion environment is significantly different, and the erosion types are diverse and complex;(2)the soil erosion moduli 〔12 000～25 000 t/(km²·a)〕 of the transmission line project in the loess hilly and gully area are significantly higher than those of the hilly area 〔3 600～9 500 t/(km²·a)〕 and plain area 〔950～2 000 t/(km²·a)〕. It can be seen that the loess hilly and gully area is the key soil erosion control area of the project;(3)the water and soil loss units in the station area and the tower base area have the largest amount of soil erosion caused by the point-type project and the line-type project respectively, and the soil erosion amounts are 27 267 t and 37 478 t, respectively; therefore, the station area and the tower base area should be the key water and soil erosion prevention and control units;(4)on the basis of engineering measures for water and soil erosion, the idea of close-to-nature governance should be introduced, and native grasses, shrubs, and tree species should be preferentially selected to integrate a comprehensive water and soil erosion control system for transmission lines in typical ecologically vulnerable areas. This article can provide theoretical basis and decision support for the prevention and control of soil erosion in power transmission line projects.