江苏沿海地区地下水演化与合理开发利用研究

发布时间：2018-02-06 05:47

本文关键词： 江苏沿海地区地下水动力场演化多重环境示踪剂淡水咸化人类活动环境地质问题　出处：《吉林大学》2017年博士论文　论文类型：学位论文

【摘要】：江苏沿海地区处于黄海之滨,是长江、淮河、黄河等河流域与海洋沉积作用条件下形成的广袤平原,该平原具有咸、淡水体共存的水环境特征。江苏沿海地区还是我国沿海、沿江和沿陇海兰新线三大生产力布局主轴线的交汇区域,在全国具有重要的战略地位。沿海地区发展规划的实施使得江苏沿海地区的社会经济迅猛发展,需水量与日俱增,地下水开采规模不断扩大。由于地下水的不合理开采,引发了一系列环境地质问题,特别是地下淡水咸化问题,严重威胁了区域淡水资源安全。本论文以江苏沿海地区为研究区,综合运用水动力、水化学、同位素、数值模拟等技术方法,确定地下水的补给来源、径流特征及排泄方式,揭示地下水位降落漏斗和淡水咸化的形成演化规律,阐明地下淡水咸化的主要影响因素,预测地下水动力场和水化学场的演变趋势,针对区域存在的环境地质问题、供水需求等,提出地下水优化开采利用方案。根据研究区1989~2012年地下水位动态监测数据、2000~2012年地下水化学动态监测数据以及2012~2015年地下水位统测和水化学采样数据,采用地下水动态分析、水文地球化学、同位素技术、数值模拟模型及地下水优化管理模型等多种方法进行地下水演化和合理开发利用研究。结果表明:(1)研究区各含水层补径排现状特征,人类开采影响下,江苏沿海地区各含水层补径排特征演变及驱动机制:潜水主要接受大气降水和北侧、西侧山区侧向径流补给,Ⅰ承压水主要接受西侧侧向径流补给,在南通市区一带接受潜水的垂向渗漏补给和长江水的侧向渗漏补给,Ⅱ、Ⅲ承压水主要接受侧向径流补给,排泄方式以侧向径流和人工开采为主,潜水、Ⅰ承压水自西向东径流排泄入海,Ⅱ、Ⅲ承压水受人工开采影响,在盐城市区、南通市区等地形成地下水位降落漏斗,地下水自漏斗边缘向漏斗中心汇聚。潜水为次现代水与现代补给水的混合;Ⅰ承压水主要接受全新世降水补给;Ⅱ、Ⅲ承压水接受全新世至晚更新世末期降水补给。沂沭河下游水文地质区和淮河下游水文地质区潜水和Ⅰ承压水水力联系密切,Ⅱ、Ⅲ承压水水力联系密切,部分区域由于弱透水层较薄,受开采影响,Ⅱ承压水向Ⅲ承压越流;长江三角洲水文地质区Ⅰ、Ⅱ承压水力联系密切。1990年~2015年25年间,Ⅲ承压水地下水补径排演化呈现随着开采量的减小,水位下降速度变缓、水位降落漏斗面积增加速度变缓的特征。(2)研究区自上而下咸水区面积呈现先增加后减小的趋势,各层地下水TDS含量自西向东逐渐增加,水化学类型则随之由HCO3-Na型向Cl-Na型演化。确定区域地下淡水咸化的主要原因是地下水过量开采,引起上覆咸水越流进入Ⅲ承压水,根据长观井监测的水位和水质资料,确定区域地下控制淡水咸化的红线水位为-10~-51m。(3)在评价现有开采规划的基础上,结合本次研究确定的控制淡水咸化的红线水位,提出分井群的地下水合理开发利用方案;考虑区内实际用水结构,提出突发状态下的分井群地下水合理开发利用方案。在充分利用区内Ⅱ承压微咸水、控制淡水咸化的情况下,典型区南通市区的地下水的优化开采量为42227m3/d,盐城-射阳区的地下水优化开采量为37477m3/d;考虑区域发生极端干旱天气或特大污染事故,各区供水量满足突发供水需求,典型区南通市区的地下水的水位范围为-15~-35.4m,盐城-射阳区的水位范围为-35.1~-49.2m。
[Abstract]:Jiangsu coastal area in the the Yellow Sea sea, Yangtze River, Huaihe, the vast plains formed in the the Yellow River River Basin and the marine sedimentation and other conditions, the plain is salty, the water environment characteristics of freshwater body coexist. The coastal areas of Jiangsu or China coast, along the Yangtze River and the confluence area along the Longhai line three main line layout, has an important strategic position in the country. The implementation of coastal development planning of the coastal areas of Jiangsu the rapid development of social economy, water demand continues to expand the scale of groundwater exploitation, grow with each passing day, due to the unreasonable exploitation of groundwater, causing a series of environmental and geological problems, especially groundwater salinization, a serious threat to regional water resources safety. This paper takes Jiangsu coastal area as the study area, the comprehensive use of water power, water chemistry, isotope, numerical simulation technique to determine the groundwater recharge The source, runoff and excretion, reveal the formation and evolution of groundwater descent funnel and saline water, clarify the main influencing factors of groundwater salinization, prediction of groundwater dynamic field and water chemistry field evolution trend, according to the environment geological problems exist in that area, water demand, put forward the optimal exploitation of groundwater utilization scheme according to the. The dynamic monitoring data of groundwater level 1989~2012, 2000~2012 dynamic monitoring data of groundwater chemistry and 2012~2015 groundwater level measurement system and water chemistry sampling data, the groundwater dynamic analysis, hydro geochemistry, isotope technology, numerical simulation model and a groundwater management model and other methods of groundwater evolution and rational development and utilization of research. The results showed that: (1) the study area of the aquifer recharge runoff discharge characteristics of the status quo, human exploitation under the influence of Jiangsu along the Haiti area of the aquifer The recharge runoff discharge characteristic evolution and driving mechanism: Diving mainly by precipitation and the north west side of the mountain, lateral runoff recharge of confined water, main receives the west side of lateral runoff, lateral recharge, in the urban area of Nantong area underwent vertical seepage recharge and phreatic water of Yangtze River II, III confined aquifer mainly recharged by lateral runoff discharge. The main way, with lateral runoff and artificial exploitation of confined water diving, from west to east the runoff discharge into the sea, II, III confined water by artificial mining, in Yancheng City, Nantong City, the formation of underground water level dropping funnel, funnel of groundwater from the edge to the sink. Diving mixed funnel center of modern times and modern water supply water; I water mainly accept Holocene precipitation recharge of confined water; II, III accept Holocene to late Pleistocene precipitation recharge. Geological hydrology downstream of Yishu River and Huaihe river water The geological area closely, diving and confined water of hydraulic connection II, III closely confined water hydraulic connection, part of the region because of the aquitard is thin, affected by mining, the confined water pressure to the II III 1 flow; hydrology geologic area of Yangtze River Delta, second confined close hydraulic connection in.1990 ~ 25 years in 2015, III artesian water groundwater recharge runoff discharge evolution with decreasing yield, water drop speed slow, drawdown funnel area characteristic rate of increase slowed. (2) the area of brackish water from top to bottom region of the study area first increased and then decreased, the water content of TDS increases gradually from the west to the East, and water chemistry types followed by the HCO3-Na type to Cl-Na type evolution. The main reason for determining regional underground water salinization is caused by excessive exploitation of groundwater, the overlying saltwater into the third artesian water, according to water level monitoring wells and water quality data, to determine the region The red line water level underground control of saline water is -10~-51m. (3) based on the evaluation of the existing mining planning, combined with the level of the red line of control of saline water, put forward the rational exploitation of groundwater wells in the area considered plan; the actual water use structure, the rational development and utilization scheme under the state of emergency divided into wells of groundwater. In the full use of zone II bearing brackish water, control of saline water under the condition of optimal exploitation in typical area of Nantong city groundwater 42227m3/d, Yancheng - Sheyang District groundwater extraction volume is 37477m3/d; considering the regional occurrence of extreme dry weather or serious pollution accidents, the district water supply to meet the emergency water demand, water level range in typical area of Nantong city groundwater is -15~-35.4m, the water level of Yancheng - Sheyang area -35.1~-49.2m.

【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：P641

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