基于区域回归水重复利用的理论灌溉水利用系数研究

Calculation Method Research Based on Regional Return Water For Theoretical Water Efficiency of Irrigation

灌溉水有效利用系数作为国民经济发展的一项重要的资源利用效率指标,也是实行最严格的水资源管理制度中用水效率控制红线的三项主要指标之一,国家提出了明确的阶段目标。通过以水量平衡法为主线,采用根据年度区域作物结构变化修正的"浮动定额"法计算了广东省1997-2011年间理论灌溉水利用系数,并以全省6个地理分区为单元,采用彭曼公式计算了历年灌溉需水量,并计算得到各年度灌溉回归水量。结果表明,期间广东省多年平均灌溉回归水利用系数为0.27,考虑灌溉回归水基础上的年度理论灌溉水利用系数值多年均值为0.56,年际间变化总体表现出灌溉水利用系数上升而回归水利用系数下降的趋势。比2005-2011年度的实测值年均高0.16,说明灌溉回归水的影响客观存在。研究对于计算区域理论灌溉水利用系数和灌溉回归水利用系数提供了新的途径。

Effective utilization coefficient of irrigation water is an important part to realize high efficient utilization of water resources. Also is one of three red line to implement the most strict water resources management system also the state made clear the stage goal. Based on the water balance method as the main line, according to the annual regional crop structure modification ＂floating ration＂ method to calculate the 1997--2011 theory utilization coefficient o{ irrigation water, and to the province＇s six districts as the basic unit with the penman method to calculate the net requirement irrigation water, Through the analysis of parameters of the two methods, using reverse subtraction calculated the annual irrigation return water. The results show that Guangdong Province during the annual the irrigation return water utilization coefficient is 0. 27, considering the irrigation return the average of annual irrigation water use coefficient is 0. 56, annual change the overall performance of the irrigation water utilization coefficient increased and return water use coefficient decreased. And compared the results with the 2005--2011 using the ＂end-to-end calculation method＂ results, Found that the average annual value than the measured height 0.16, indicating that the impact of irrigation return water objective ex- istence. The study for the theoretical calculation of utilization coefficient of irrigation water and irrigation return water use coefficient provides a new way, the results for the guidance of irrigated areas and raise the efficiency of irrigation water has important practical significance.