地下水资源管理预警系统的建立及应用研究——以长春城区为例

由于长春城区地下水的超采产生了环境恶化,结合地下水预测模型和地质及水文地质条件,以长春城区为例建立了地下水资源管理预警模型。根据长春城区的地质及水文地质条件提出水位水质预警标准,并根据模型编制了地下水资源管理预警系统。利用所建立的预警系统,对现状和未来开采条件下水位水质进行预警,从而为水资源的科学管理和持续利用提供可靠依据和保障。     

Groundwater regime and calculation of yield response in North China Plain: a case study of Luancheng County in Hebei Province

The groundwater table has been declining at a rate of 0.65 m/yr in Luancheng County since large scale groundwater extraction carried out in the 1960s. The drop of precipitation, substantial increase in agricultural output, variations of crop planting structure and construction of water conservancy projects in the headwater area all tie up with the decline of the groundwater table. On the basis of analyzing the hydrogeological conditions and the water resources utilization of Luancheng County, a three-dimensional groundwater flow model was developed to simulate the county’s groundwater flow through finite-difference method using Visual Modflow software. We divide the research field into four parts after analyzing the hydrogeological condition. Based on parameter calibration and adjustment using measured data, the hydraulic conductivity and specific yield were simulated. Using the calibrated model, we analyze the agricultural water saving potentiality and its influence on the groundwater. The results are as follows: (1) if we decrease the amount of water extracted by 0.14xl0⁸ m³, the average groundwater table of the five observation wells in December will rise by 0.33 m; (2) if we decrease the water by 0.29x 10⁸m³, the average groundwater table of the five observation wells in December will rise by 0.64 m; and (3) if we increase the water by 0.29 x 10⁸m³, the average groundwater table of the five observation wells in December will decline by 0.45 m. So we can draw a conclusion that controlling the agricultural water use is an important way to prevent the decline of groundwater table.     

西部公路路基内部排水效果模拟研究

以半挖半填路基为例，讨论了各类地质单元与路基系统的作用及路基系统内部地下水运动特征，着重分析了地下水对路基边坡稳定性的控制作用，通过敏感性分析，阐明了降低路基边坡地下水位的必要性，研究了地下水对路基系统的作用机理；建立了路基排水的数学模型，对影响路基排水的降雨强度、渗沟间距、排水时间等因素进行了敏感分析；通过对路基系统渗透系数、入渗系数、降雨量及初始水头的不同取值，运用Modflow软件对排水效果进行了模拟；通过工程实例，验证了路基排水设计方案的合理性。     

水利工程建设对地下水影响的数值模拟分析

工程开挖及建成后对含水层结构的改造,无疑会对开挖区周围地下水造成影响。利用数值模拟方法分析预测某水利工程尾水渠开挖及建成后周围地下水水位的变化。预测结果,大开挖后周边地下水位将快速降低,且不同地段水位降幅不同,右岸阶地内水位降低约0.26~7.26 m,工程建成后,阶地内水位将逐渐恢复,但相比施工前水位仍降低0.09~0.38 m。分析水文地质结构,合理概化,建立数值模型,对于分析工程开挖对地下水的影响,是种有效方法。     

An iterative technique to delineate protection buffers for wetlands in regions subject to intensive groundwater pumping

Wetlands are vulnerable to groundwater extraction, which has proven detrimental to aquatic ecosystems around the planet. As wetlands rank among the world’s most endangered ecosystems, versatile strategies are required to protect them. This paper provides a modelling-based method to delineate protection buffers in wetlands subject to groundwater extraction. The technique is sufficiently flexible to cater to a wide variety of conditions, and simple enough to underpin management decisions on a daily basis. A numerical model is used to obtain a map of the critical rate of groundwater abstraction, based on the distance between wetlands and suitable discharge thresholds. The outcomes determine the allowed pumping rate at any point under steady and transient-state conditions. A new iteration is developed every time a new pumping allowance is made. This procedure is demonstrated by means of hypothetical scenarios, as well as by a case study application in the Valle del Cauca region, Colombia.     

VisualModflow模型在白涧铁矿区矿井涌水量预测中的应用

在分析确定白涧矿区水文地质边界条件的基础上,运用实测资料对Visu-almodflow模型进行识别和验证,同时修正了含水层的参数,修正后的模型较为可靠,可用于白涧矿区涌水量的预测。依据矿区奥灰含水层边界条件和渗透系数的不同,设计了-200m和-400m水平面不同边界及渗透系数三个方案对矿井的涌水量进行预测。结果表明:方案2的涌水量比较合理,能较真实的反映白涧铁矿矿体分布区水位疏降至-400m时的涌水量情况,预测其涌水量为7505m3/h。      

Visual Modflow在甘肃某矿区地下水数值模拟中的应用

在分析甘肃某矿区的水文地质条件基础上,建立了研究区水文地质概念模型,运用国际的可视化标准软件 Visual Modflow 对研究区地下水进行了数值模拟计算,预测了区内地下水水位随时间缓慢上升,地下水处于微弱正均衡状态,地下水位将以高于1 m幅度升降,极限水位是1.6 m,矿区地下水水位边界线将向东南侧(厂址范围)移动约214 m,距离厂址范围边界最近287 m,地下水水位上升后对拟建厂址范围内项目建设无安全影响,同时为今后研究矿区地下水资源的合理开发利用、矿区建设及环境保护等提供了科学依据.     

基于GMS的Solids建模地层的转化与修正方法探讨

地下水数值模拟软件GMS以其友好的界面、强大的处理功能和优良的三维可视效果受到人们的广泛的应用。建立Modflow模型有三种方法:网格法、概念模型法和Solids法,利用Solids法建立复杂地层模型能起到事半功倍的效果。针对不同的四种地层类型,论述了地层空间信息转化成Modflow模型中的顶底板标高步骤中关于地层转化和修正的方法。     

Application of Numerical Modeling for Groundwater Flow System Analysis in the Akaki Catchment,Central Ethiopia

A three dimensional steady-state finite difference groundwater flow model is used to quantify the groundwater fluxes and analyze the subsurface hydrodynamics in the Akaki catchment by giving particular emphasis to the well field that supplies water to the city of Addis Ababa. The area is characterized by Tertiary volcanics covered with thick residual and alluvial soils. The model is calibrated using head observations from 131 wells. The simulation is made in a two layer unconfined aquifer with spatially variable recharge and hydraulic conductivities under well-defined boundary conditions. The calibrated model is used to forecast groundwater flow pattern, the interaction of groundwater and surface water, and the effect of pumping on the well field under different scenarios. The result indicates that the groundwater flows regionally to the south converging to the major well field. Reservoirs and rivers play an important role in recharging the aquifer. Simulations made under different pumping rate indicate that an increase in pumping rate results in substantial regional groundwater level decline, which will lead to the drying of springs and shallow hand dug wells. Also, it has implications of reversal of flow from contaminated rivers into productive aquifers close to main river courses. The scenario analysis shows that the groundwater potential is not enough to sustain the ever-growing water demand of the city of Addis Ababa. The sensitivity and scenario analysis provided important information on the data gaps and the specific sites to be selected for monitoring, and may be of great help for transient model development. This study has laid the foundation for developing detailed predictive groundwater model, which can be readily used for groundwater management practices.     

Processing Modflow在基坑疏干抽排水中的应用

以天津某基坑为研究对象,采用Processing Modflow数值模拟软件建立了地下水三维渗流与地面沉降耦合模型。模拟了基坑疏干抽排水在完成支护、止水帷幕施工条件下其周边地下水位和地面沉降的实时变化:即由于疏干抽排水引起的基坑周边约80 m内地下水水位降幅在0.90~82.15 cm之间,约80 m内地面沉降量在0.001~26.21 mm之间。模拟结果与后期监测数据吻合较好,能够较为真实的反映降水过程对周边环境的影响。