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[摘要]
我国在河北开展地下水超采综合治理试点,为了掌握各项措施的实际压采效果与技术经济性,采用现场抽 水灌溉试验、入户走访调查等手段,通过治理区地块与非治理区地块治理前后地下水灌溉用水量的对比,分析总 结各项措施的压采效果与实施经验,并通过治理措施的投入成本与压采效果对比,研究剖析各项治理措施的技术 经济性。研究结果表明:治理措施较好地发挥了减少地下水开采的作用,种植结构调整措施和水源置换措施减少 地下水开采量超过 2?400?m3/hm2;高效节水灌溉措施、水源置换措施实施初期所需建设投资较大,导致单位压采量 所需投资较高,农业种植结构调整类措施实施初期的投资相对较低,但后期单位压采量所需投资逐年增加。从压 采效果、技术经济性、水源条件与超采类型及程度 4 个方面,对不同地区选择治理措施给出建议,为今后地下水 超采治理提供参考。
[Key word]
[Abstract]
A comprehensive groundwater overdraft control pilot project was launched in Hebei Province, China due to severe groundwater overexploitation problems, and many control measures were implemented including highly efficient irrigation, water source replacement, planting structure adjustment, etc. The performance, implementation difficulty, and investment of different measures vary drastically. To further upscale and promote the pilot project, the comprehensive evaluation of each measure became increasingly important. Many existing studies focus on the evaluation of the overall effect of the project, such as reduced pumping rate, water level change, storage change, etc., but failed to answer the question of the performance and economic efficiency of specific measures. Different research methods had been used synergistically including irrigation on-site tests, household visits, surveys, technical and economic analysis. Comparative experiments on the same crop with different irrigation methods were conducted yearly throughout the whole duration of the project within the pilot and non-pilot areas in Shijiazhuang, Cangzhou, Hengshui, Xingtai and Handan. The water-saving capacity was attained by analyzing the water consumption of traditional irrigation methods, and water-saving irrigation methods. The performance of different control measures for the whole pilot area was calculated based on the groundwater abstraction rate change analysis before and after the comprehensive governance. The input-output ratio of different groundwater overdraft control measures was estimated by calculating the investment per unit of reduced groundwater extraction. The investment equaled the initial investment and the additional cost for the following years. The reduced groundwater extraction could be deduced using the groundwater abstraction rate change from the performance evaluation. The results show that adopted measures played an essential role in alleviating groundwater overdrafts. Taking the wheat-maize planting pattern as an example, the annual saved water per hectare of sprinkling irrigation, rainfed farming, pipe irrigation, integration of water into fertilizer, following, and replacing with non-agriculture crops reached 600-1 200 m3, 2 700 m3, 600-1 200 m3, 600-1 200 m3, 2 700-4 200 m3, 2 400-2 700 m3, respectively, compared to traditional irrigation. The drip irrigation to vegetables could save water up to 2 700 m3per hectare, and 3 900 m3 of water per hectare could be saved by water source replacement. The initial annual investment for water-saving irrigation and water source replacement was 16.7 yuan/m3, while the annual initial investment for replacing the non-agricultural crop, rain-fed farming, and the following was only 8.8, 4.2, and 2.6 yuan/m3, respectively. But the annual investment for the latter three methods in the last year reached 26.5, 20.8, and 12.8 yuan/m3. This concluded that planting structure adjustment and water source replacement have posed an obvious effect on reducing groundwater extraction. The high-efficiency water-saving irrigation and water source replacement methods require relatively high construction investment at the initial stage, making the cost of a single unit higher. The initial investment in planting structure adjustment is relatively small, but the investment of a single unit could reduce extraction increased linearly year by year. By combining the results of the performance evaluation and the input-output ratio of different control measures, the applicable scenarios and priorities could be deduced, which could work as a reference for the management of groundwater overdraft control in the future.
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