基于农牧业需水特性的洋河流域农业水资源优化配置

针对洋河流域水资源短缺与水环境污染问题日益突出,以及考核断面水质难以达标等问题,为了实现水资源充分利用与环境保护的双重目标,结合流域经济社会发展及水资源开发利用现状特点,以洋河流域为研究对象,考虑水质约束,构建了农业水资源优化配置模型。在保障考核断面水质达标前提下,通过优化各月份不同作物和牲畜的配水量,以及作物种植面积和牲畜养殖数量,以实现农业经济效益最大化。为提高水质和实现水资源充分利用,提出补水减排联合控制水质达标方法,并基于农牧业需水特性配水,可避免非均衡给水情形的发生。同时,能有效降维,提升模型求解效率。以2014年为例,采用该模型优化计算,通过增加高效益的蔬菜、薯类种植面积和大牲畜的养殖数量,减少排污大的油料作物种植面积和小牲畜养殖数量,可实现考核断面水质达标,且农业配水量减少3.38%,经济效益增长11.96%,验证了该模型的有效性。再模拟分析2020年丰平枯3种典型水文年的优化配置方案,结果表明:随着可供水量的增大,农业配水、河道补水量会相应增加,大部分需水用户和子区的配水量也会随之增加。子区中的怀来县和宣化区的配水量增量较大,需水用户中谷物和水果的配水量增量较大,牲畜配水量增量小于农作物。需水用户的配水量增长率与其面积相关,子区间的配水量增长率与其区内作物类型和种植面积相关,以及水量分配是可供水量、污染排放量、经济效益综合权衡结果。该配置模型对于保障洋河流域的水质安全及区域经济可持续发展具有重大意义,并对考虑水质的水资源优化配置有一定的参考作用。

Optimal allocation of agricultural water resources in Yanghe River Basin based on water requirement of agriculture and animal husbandry

Abstract: With the growth of population and the rapid development of social economy, the shortage of water resources and the pollution of water environment in Yanghe River Basin have become increasingly prominent, which leads to the water quality in the assessment section of Yanghe River Basin is difficult to meet the water quality standard. In order to achieve the efficient utilization of water resources and environmental protection, combining with the characteristics of economic development and water resources utilization, an optimal allocation model of agricultural water resources was established with the water quality constraints for Yanghe River Basin. Therefore, under the premise of the water quality of assessment section, the monthly water allocation of different crops and livestock, as well as the crop planting area and the livestock number were optimized to maximize agricultural economic benefit. The paper proposed a method to control water quality by supplying water and reducing pullution simultaneously. Moreover, based on the water water requirement of agriculture and animal husbandry, this paper introduced a method to avoid unbalanced water supply problems and reduce the dimension to improve the solution efficiency. The optimization results showed that the assessment section of the Bridge 8 could be adjusted to meet the water quality standard by increasing the planting area of the vegetables and the tubers with higher benefit, as well as the large livestock number, and decreasing the planting area of oilseeds with severer emission, as well as the small livestock number. Comparing with the actual values in 2014, the agricultural water allocation decreased by 3.38%, and the economic benefit increased by 11.96%. Therefore, the model was verified effectively. Furthermore, the paper analyzed the optimization allocation schemes under different conditions of the low, median and high flow years in 2020. The results showed that, the more water quantity available, the more agricultural water allocation and river recharge correspondingly. In this condition, water allocation of most water users and subzones were also increased, of which Huailai and Xuanhua had larger increments. Besides, the water allocation of crops was larger than that of livestock, and the grains and fruits had larger increments. The increase rate of water users was relative to planting area, while the increase rate of subzones was relative to the crop type and planting area, and water allocation was the comprehensive tradeoff among available water for agriculture, pollution emissions and economic benefits. The proposed model is of great significance for ensuring water quality safety and sustainable development of regional economy in Yanghe River Basin, and has a certain reference value for optimizing allocation of water resources considering water quantity and quality.