近40年三江平原典型区土地利用变化及其对地下水的影响

三江平原是我国重要的商品粮基地和粮食战略储备基地,地下水作为该地区的主要灌溉水源,其动态备受关注。选取三江平原典型区1980、1990、2000、2010及2018年五期遥感影像数据进行土地利用变化特征分析,探究土地利用类型变化对地下水位埋深的影响和城市化进程、耕地面积变化对流域水均衡状态的影响。结果表明:近40年来水田与城镇用地的面积和周长存在显著的分形特征,稳定性指数由强—弱—强,两种土地利用类型的重心在近40年内发生明显迁移且迁移方向主要为西南—东北—西南,其直接影响流域水均衡状态。土地利用类型的改变使得部分地区地下水补给恢复较慢,造成地下水位埋深不同程度地增大。城市化发展对大气降水入渗补给量影响相对较小,耕地面积变化对灌溉回归补给量影响显著。研究结果可为构建更准确的三江平原典型区地下水数值模型提供科学依据,为三江平原地下水的可持续开发利用提供理论参考。     

The Combined Use of Groundwater Quality,Drawdown Index and Land Use to Establish a Multi-Purpose Groundwater Utilization Plan

Groundwater is abundant and widely used for household consumption, irrigation, and aquaculture in the Lanyang Plain in northeastern Taiwan. However, it is subject to contamination by various anthropogenic activities and natural processes, as well as overexploitation, which has led to land subsidence in the eastern coastal area of this plain. It is becoming increasingly urgent to establish a sound plan for groundwater resource management in the Lanyang Plain to ensure the safe and sustainable use of groundwater to meet demands. The aim of this study is to develop a sound management plan for multipurpose groundwater utilization in the Lanyang Plain. This plan is developed with consideration of the quality and quantity of groundwater, as well as current land use practices. First, the groundwater quality parameters are spatially mapped followed by geographic determination of regions where groundwater quality is safe for different purposes, based on the water quality criteria for drinking, irrigation, and aquaculture. Subsequently, the drawdown index, defined as the ratio of the actual groundwater utilization rate to the transmissivity, is determined for each cell and low drawdown index regions are identified geographically. Information about regions where groundwater quality is safe for different purposes and the regions where the drawdown index is low is integrated to create a map which can be used for the production of a sound management plan for multi-purpose groundwater utilization in the Lanyang Plain. Comparisons between our newly created map and current land use for farmlands and fishponds can provide a basis to review the current land use practices in these regions.

     

Groundwater Exploitation and Its Impact on the Environment in the North China Plain

Abstract

The North China Plain (NCP) is one of China's most important social, economic, and agricultural regions. Currently, the Plain has 17,950 thousand ha of cultivated land, 71.1 percent of which is irrigated, consuming more than 70 percent of the total water supply. Increasing water demands associated with rapid urban and industrial development and expansion of irrigated land have led to overexploitation of both surface and the ratio of groundwater resources, particularly north of the Yellow River. In 1993, the ratio of groundwater exploitation to recharge in many parts of the NCP exceeded 1.0; in some areas, the ratio exceeded 1.5. Consequently, about 1.06 million ha of water-short irrigated areas in the NCP also have poor water quality. Persistent groundwater overexploitation in the northern parts of the NCP has resulted in water-level declines in both shallow and deep aquifers. According to data from 600 shallow groundwater observation wells in the Hebei Plain, the average depth to water increased from 7.23 m in 1983 to 11.52 m in 1993, indicating an average water-table decline of 0.425 m/year. Water table declines are not uniformly distributed throughout the area. Depletion rates are generally greatest beneath cities and intensively groundwater-irrigated areas. Water-table declines have also varied over time. With the continued decline of groundwater levels, large depression cones have formed both in unconfined and confined aquifers beneath the Hebei Plain. Groundwater depletion in the NCP has severely impacted the environment. Large tracts of land that overlie cones of depression have subsided, seawater has intruded into previously freshwater aquifers in coastal plains, and ground-water quality has deteriorated due to salinization, seawater intrusion, and untreated urban and industrial wastewater discharge. In order to balance groundwater exploitation with recharge, the major remedial measures suggested are to strengthen groundwater management, to raise water use efficiency, to adjust the water-consumed structure, and to increase water supply     

基于SWAT的灌区分布式水文模型——Ⅰ.模型构建的原理与方法

针对中国南方丘陵水稻灌区水文特点，在对自然流域水文模型SWAT改进的基础上，构建了灌区分布式水文模型，改进了SWAT的灌溉水运动模块、稻田水分循环模块、稻田水量平衡各要素和产量模拟的计算方法，改变了陆面水文过程的计算结构，增加了渠系渗漏模拟模块及其对地下水的补给作用、塘堰的灌溉模块等。以湖北省漳河灌区内的一个闭合小流域为例，对构建的灌区分布式水文模型进行校正和验证，模拟结果显示，该模型适合于水稻灌区水分循环的模拟。     

冀中山前平原农灌用水与地下水承载力适应性状况

针对冀中太行山前平原浅层地下水严重超采与农林灌溉用水之间关系问题,应用地学的模数理念、水量均衡理论方法和MapGIS空间特征分析技术,建立了农灌用水与地下水承载力之间适应性状况评价方法及指标体系,以0.49km2剖分单元精度识别了冀中山前平原农林灌溉用水强度及其与浅层地下水可采资源量之间适应性状况。结果表明,冀中山前平原农林灌溉导致的"极严重不适应"或"严重不适应"状态是浅层地下水超采的主要原因,其中小麦等夏粮作物灌溉用水主导了这些农灌区地下水超采,蔬菜作物和耗水型果林灌溉开采对地下水的影响呈显著增加趋势,应重视这种非理性加剧影响因素。     

Conjunctive use of groundwater and surface water to reduce soil salinization in the Yinchuan Plain,North-West China

Abstract

Poor water resource management is an important factor in soil salinization in arid areas. In this study, the status of soil salinization and its controlling factors are summarized for the Yinchuan Plain, North-West China. The conjunctive use of surface water diverted from the Yellow River and groundwater abstracted from a shallow aquifer is proposed to alleviate soil salinization in the plain. Scenarios are designed and simulated to determine the optimal proportions at which groundwater should be exploited for irrigation in the three cities of the plain. Policies and suggestions regarding sustainable water resources and soil salinization research in the plain are recommended.     

宁夏平原区分布式水循环模拟研究

根据平原区水循环的特点，建立了平原区分布式水循环模型，该模型以日为计算时段，根据行政区域、引排水渠道覆盖的灌域、土地利用类型以及作物种植结构划分水循环计算单元。模型以水平衡为基础，在任一计算单元沿垂直方向均可分为植被冠层、地表水、土壤浅层、土壤深层、潜水层和承压水层，按照水域、植被、裸地、农田、不透水域等不同土地利用类型计算蒸散发量，地表水模拟包括引水系统、排水系统、湖泊湿地和生活及工业用水系统。应用该模型详细模拟了宁夏平原区1991～2000年的水循环转化过程和供、用、耗、排水量关系，计算结果表明，若不加上黄河河道蒸发消耗水量，2000年平原区实际消耗黄河干流水量为33.53亿m3。     

Groundwater Resource Use Practices and Implications for Sustainable Agricultural Development in the North China Plain: A Case Study in Ningjin County of Shandong Province,PR China

This paper addresses the critical situation of water resource exploitation for agriculture and environmental effects in Ningjin County in the North China Plain. Several negative environmental effects such as declining groundwater table levels, decline in groundwater quality, increased irrigation cost, increased soil salinity, compaction of soil, increased land subsidence and increased incidence of waterlogging have been experienced in the area, as perceived by the local farmers. This is due to overpumping of groundwater by a large number of wells clustered in small areas. The study indicates that if the current pattern of groundwater use, existing attitudes of farmers and improper implementation of policies and regulations is continued, the agricultural activities will face severe consequences and tend to be unsustainable. This warrants new strategies to improve the present situation.     

开都河河道渗透补给地下水分析

干旱典型区焉耆盆地的农业灌溉可持续发展,受制于开都河河水以及开都河流域地下水的有效利用。在总结河道渗透补给地下水量计算方法的基础上,选用河道水量平衡法对开都河枯水期河道渗透补给地下水量做了分析,得出该河流河水与地下水的补排关系及补排量。以期对焉耆盆地合理利用水资源、改善生态环境、农业灌溉可持续发展提供一定的依据。     

EFFECT OF GROUNDWATER TABLE CONTROL ON WATER SAVING IRRIGATION STRATEGIES IN THE QINGTONGXIA IRRIGATION DISTRICT

This paper focuses on the analysis of the effects of groundwater table control under different irrigation water amounts on the water and salinity balance and on crop yield. Two experimental areas, the Pingluo and Huinong experimental sites, were selected to collect the required data. The agro-hydrological model Soil Water-Atmosphere-Plant (SWAP) was used to analyse the water flows and salt transport processes for different groundwater levels and irrigation scenarios. Six scenarios, which resulted from different groundwater table regimes combined with different irrigation amounts, were simulated. The results show that high groundwater tables due to the excessive irrigation are the main cause of the large amount of drainage water and low crop yield;reducing irrigation water without a lower groundwater table will not lead Io a large reduction of the drainage water, and will reduce the crop yield even more; to lower the groundwater table is a good measure to control the drainage water and increase crop yield.