宁夏扶贫扬黄灌溉工程水土保持监测及评价

Technique and evaluation of soil and water conservation monitoring of the poverty alleviation project in the Yellow River region of Ningxia

为了评估宁夏扶贫扬黄灌溉工程建设对当地生态环境造成的影响和水土资源破坏的程度,运用水蚀径流场法、水蚀侵蚀沟法、水蚀控制断面卡口站法和风蚀简易小区法4种不同的水土流失量监测方法,采用由水土流失危害程度指标、生态环境指标、水土保持工程措施、植物措施、综合防治措施实施效果等构成的指标体系来评价工程建设过程中水土保持措施实施效果。通过实时监测,最终得出:项目区8年间扰动土地整治率达到98.2%,水土流失总治理度达到98%,土壤流失控制比达到1.24,植被恢复率达到93.7%,植被覆盖率达到10.7%,扰动后土壤侵蚀强度高达9 600 t/(km2·a),工程护坡减沙率为50%,造林减沙率为65.22%,人工种草减沙率为71.52%。本工程采用的水土保持监测方法、实测数据、应用指标等对同类开发建设项目工程在投资决策、建设实施及后期评价方面具有借鉴作用。

The objective of this study was to evaluate the effect of poverty alleviation project construction in the Yellow River region of Ningxia on environment and the degree of destroying water and soil resources. Four methods were adopted to measure the loss of water and soil, i. e. , water erosion runoff field method, erosion gully monitoring method, bayonet check station of the water erosion control section monitoring method and the simple wind erosion area monitoring method. An index system was used to evaluate the implementation effect in the process of engineering construction. The index system is comprised of soil erosion hazard degree index, ecological environment index, measures of soil and water conservation project, vegetation measures and comprehensive measures. Through real-time monitoring, we concluded that： during the eight-year project, the rate of renovation of disturbed land reached 98.2% , the general harnessing degree of water and soil erosion reached 98% , the soil erosion control ratio reached 1.24, vegetation recovery rate of the project achieved 93.7%, vegetation coverage rate achieved 10.7% , intensity of disturbance of soil erosion was up to 9 600 t/（ km2 ~ a） , the sediment reduction rate of engineering revetment was 50% , the sediment reduction rate of artificial afforestation was 65.22% , and the sediment reduction rate of planted grass was 71.52%. The methods of soil and water conservation monitoring, the measured data, the applied indexes etc. used in this project, are of important reference value in investment decision, construction implementation and late evaluation for similar construction projects in the future.