Innovative Trend Methodology Applications to Precipitation Records in Turkey

There are trend identification methodologies in the literature but they have three crucial points that should be cared with great attention in practical applications. These points are that the available time series should have independent serial correlation structure, Gaussian (normal) distribution and monotonic trend fitting to whole time series through the least square technique. The existing methods consider the whole duration of the time series and try to identify a monotonic trend in increasing or decreasing forms. This paper presents partial trend methodology as an innovative and simple trend identification method, which yields low, medium and high cluster trends separately. It provides the opportunity to segregate between the low, high and medium flow trends and their relative intensities, durations as well as magnitudes. The application of the partial trend methodology is presented for 7 precipitation stations from 7 different sub-climatic regions of Turkey leading to spatial and temporal trend interpretations.     

Partial Wavelet Coherence to Evaluate Scale-dependent Relationships Between Precipitation/Surface Water and Groundwater Levels in a Groundwater System

Water Resources Management - Identifying the scale-dependent control of various surface factors on a groundwater system is a challenge due to the potential interdependence between these factors....     

Multilayer Feed Forward Models in Groundwater Level Forecasting Using Meteorological Data in Public Management

Managing the groundwater resources is very vital for human life. This research proposes a methodology for predicting the groundwater levels which can be very valuable in water resources management. This study investigates the application of multilayer feed forward network models for forecasting the groundwater values in the region of Montgomery country in Pennsylvania. Multiple training algorithms and network structures were investigated to develop the best model in order to forecast the groundwater levels. Several multilayer feed forward models were created in order to be tested for their performance by changing the network topology parameters so as to find the optimal prediction model. The forecasting models were developed by applying different structures regarding the number of the neurons in every hidden layer and the number of the hidden network layers. The final results have shown a very good forecasting accuracy of the predicted groundwater levels. This research can be very valuable in water resources and environmental management.     

Groundwater legislation in Turkey: problems of conception and application

The uneven distribution of water resources, a growing population, urbanization and global climate change require new approaches for groundwater management in Turkey. “Safe yield” should yield to broader concepts such as “sustainability”. Groundwater management needs to consider future needs of the people and all ecosystems in accordance with basin development models. Groundwater law needs to be expanded beyond quantity to address quality concerns. A new institutional framework should be established and groundwater regulation should reflect new approaches and ideas, in particular to address problems of application.     

Spatial Analysis of Monthly and Annual Precipitation Trends in Turkey

Global climate change could have important effects on various environmental variables in many countries around the world. Changes in precipitation regime directly affect water resources management. So that, it is important to analyze the changes in the spatial and temporal rainfall pattern in order to improve water resources management policies. For this reason, non-parametric Mann-Kendall rank correlation test is used in order to examine the existence of trends in annual and monthly rainfall distribution. To understand the regional differences of precipitation in Turkey, the detected trends are spatially interpolated using geostatistical techniques in a GIS environment. The main objective of this paper is to evaluate three interpolation methods, concerning their suitability for spatial prediction of temporal trends of Turkey’s monthly and annual rainfall data. The study used a dense and homogeneous monthly precipitation database comprising 120 rain-gauge stations over a 32 years testing period of 1975–2009. The results conclusively show that significant positive trends are both infrequent and found only in outlying stations during March, April and October. In order to estimate and characterize the magnitude of observed changes at unmeasured locations, Ordinary Kriging, Inverse Distance Weighted and Completely Regularized Spline interpolation methods were employed and compared. A comparative analysis of interpolation techniques shows that Ordinary Kriging with having RMSE of 0.148 is the best choice. This is followed by Inverse Distance Weighted (RMSE 0.151), and Splines (RMSE 0.152). Cross validation of the results shows the largest over prediction at Kars rainfall station and largest under prediction at Burdur station. Upon for the examination of the cross-validation and spatial error clustering results, the Ordinary Kriging method was concluded to be the best algorithm in the interpolation process.     

降水和开采变化对滹滏农业区地下水流场影响特征与机制

准确认识地下水流场演变机制是开展地下水系统涵养修复的前提和基础。以滹滏农业区为典型区,基于该区逐月地下水动态观测和降水资料,采用区域地下水动态模型及时间序列趋势分析等方法,开展了降水和开采变化对农业区地下水流场影响特征与机制研究。结果表明:降水变化是驱动地下水位变幅的重要因素,在枯水年份地下水位下降阈值介于0.5~4.0 m,在平水年份下降阈值介于0~2.0 m,在丰水年份地下水位大幅上升;地下水位与开采量关系不明显,但与区域累计超采量有显著的相关关系,地下水累计超采量每增加1.0亿m3正定农业区地下水位下降6.4 m、藁城农业区下降7.3 m。随降水量的增大,农业区开采强度呈幂函数减少趋势,地下水补给量呈幂函数增长趋势。农业开采减少趋势线和地下水补给增加趋势线的交会点为地下水系统平衡点,在平衡点左侧的年份地下水系统处于负均衡状态,离平衡点越远地下水位下降幅度越大;在平衡点右侧的年份地下水系统处于正均衡状态,离平衡点越远地下水位上升幅度越大。研究成果可为区域地下水开发利用提供理论指导。     

Impact of Flood Spreading on Groundwater Level Variation and Groundwater Quality in an Arid Environment

In arid and semiarid areas, bimodal and high rainfall leads to infrequent flood that can be extremely damaging. To reduce the impacts of persistent intra-seasonal drought and also to reduce flood damaging in arid and semiarid areas, rainwater storage is a prerequisite that keeps water far from evapotranspiration, increases groundwater level and decreases flood hazards modification to exchange between surface water and groundwater through flood spreading, dams, etc. The purpose of this paper is to delineate and explain variations in groundwater recharge and groundwater quality along an ephemeral stream that has been modified by flood spreading. Groundwater samples were collected from 14 deep wells located at different distances from flood spreading projection area (FSPA) in 1 month interval during September 2005 to September 2008. Groundwater quality was followed via Na⁺, K⁺, Ca²⁺, Mg²⁺, Cl^-, Hco₃^- SO₄^2-, Electrical Conductivity (EC) and pH measurements for two time periods between 2005 and 2008. The results show significant impact of flood spreading in groundwater table and groundwater salinity variation. Groundwater table decreased in all study wells, but groundwater drawdown increased by increasing the distance to FSPA (during 4 years study, 11.02 m in the well located at 20 m of FSPA versus 38.88 in the well located at 1,825 m). Also ion concentration increased in all of the wells during the study period, but the increasing ion concentration was significantly less important in FSPA closeness.     

甘肃天水地区降水量对气温的影响研究

以甘肃天水地区实测资料为基础,应用最小二乘法原理拟合出该地区气温与降水量之间的函数关系式,其相关系数约为0.96,为以后该地区气温的预测提供理论基础。     

香溪河流域降雨产沙分形关系及前期有效降雨计算

为探讨流域前期有效降雨量计算的新方法,依托香溪河流域兴山水文站1974—1989年264场次降雨产流产沙资料,研究了流域次降雨产沙频度与降雨量的关系,采用分形理论与方法,并基于产沙累积频度-降雨量分形关系,推导出流域前期有效降雨量计算方法,且试算了流域前期有效降雨。结果表明:香溪河流域次降雨引起产沙累积频度与降雨量之间遵循分形的幂指数关系,在2个降雨量范围内具有不同的标度指数;按照幂指数关系拟合的产沙累积频度与降雨关系线交点处的降雨量,发现引发78%左右的产沙累积降雨阈值上边界;在香溪河流域,降雨发生前0,1,3,5,7 d的5个时间段累积降雨量阈值分别为26.6,29.2,35.3,43.2,47.8 mm;基于累积产沙频度-降雨量分形关系计算流域前期有效降雨的方法能更加反映真实情况。     

The Hysteresis Response of Groundwater to Reservoir Water Level Changes in a Plain Reservoir Area

Water Resources Management - Reservoir immersion will lead to some environmental geological problems, such as soil swamping or salinization, reduction of building foundation strength, or even...     

许昌市地下水位动态变化及影响因素分析

依据许昌市1980-2018年地下水位监测资料,对该地区地下水位的动态变化特征及其影响因素进行分析。研究结果表明：许昌市地下水位动态规律随着空间分布的变化而有明显的差异;多年来,许昌市地下水位总体呈波荡起伏趋势,动荡幅度较大且在突变点出现在1980年、1992年和2003年;许昌市地下水位动态变化主要受降水状况和开采条件的影响。     

中国地下水供水量与经济发展的脱钩趋势及空间聚集性研究

研究全国各省区地下水供水量与地区生产总值的脱钩关系,对于今后优化调整供水结构,强化地下水资源的保护与修复具有重要意义。采用2000—2020年全国31个省区供水量、地区生产总值和人口数量资料,运用脱钩分析、驱动效应分析和空间相关分析方法,对全国近20 a来地下水供水与地区生产总值之间的脱钩状态和主要驱动因素进行研究,并探讨各驱动因素在省区尺度的空间聚集特征。结果表明:我国地下水供水量与经济发展的脱钩状态总体上由弱脱钩逐渐演变为强脱钩,2013年是由弱脱钩转变为强脱钩的分界点;用水效率提升是驱动地下水供水减少的主要因素,人均GDP增长是导致地下水供水增加的主要因素;“十五”至“十一五”期间,各省区以弱脱钩为主,“十二五”至“十三五”期间,强脱钩省区处于主导地位;“十五”至“十三五”期间,影响脱钩状态的主要因素从经济水平逐渐演变为用水效率和供水结构;“十三五”末期,各驱动效应贡献率均呈现H-H聚集或者L-L聚集特征。     

河套灌区地下水时空变化趋势成因分析

内蒙古河套灌区降水稀少,蒸发强烈,灌区地下水埋深不仅决定了区域水量平衡、水盐平衡、水热平衡,还将对区域生态系统产生重大影响。通过收集整理内蒙古河套灌区216眼观测井2003—2013年逐月地下水埋深观测资料,采用变异函数分析方法,并借助Arc GIS等手段,建立数学模型,研究了灌区地下水埋深在年内和年际的演变规律和空间变异特性;通过春灌、秋浇等典型灌溉期的水量平衡分析,揭示了地下水位变化的主要影响因素和物理机制;根据灌区自然地理特点、灌水习惯、可能的节水措施,拟定了3种节水模式,预测了不同模式下的地下水位变化幅度,结果表明,渠系水利用系数提高到国家标准0.55时,灌区的地下水埋深将比2013年的2.05 m增大0.26 m,达到2.31 m。     

太原市兰村泉域地下水位下降的成因及防范措施

本文通过对太原市兰村泉域内兰村、西张、枣沟三大水源地地下水开采量、水位、水质的分析 ,阐述了兰村泉域地下水因过量超采 ,造成在泉域内大范围的地下水位下降 ,部分地区形成地下水水位降落漏斗 ,从而导致水质污染、地面沉降等问题。进而提出了分质供水、优质优用的供水方式和做好人工回灌、调减限制地下水开采量等防范措施。     

宝鸡峡灌区灌溉用水量与降水量的相关分析

宝鸡峡引渭灌区是一个地处半干旱地区 ,设施面积 30 0万亩 ,窄而长的带状灌区。区内多年平均降水5 70 .9mm。量少 ,而且具有在时空分配上与作物需水量不协调等特点 ,从而决定了灌区系补天然降水之不足的灌溉性质。降水丰沛且适时 ,作物需要灌溉补充的水量就少 ;反之 ,天气干旱 ,或降水与作物需水量不吻合时 ,则作物需要灌溉补充的水量就多。因而 ,灌溉用水量与降水量有着密切的关系。同时 ,灌区内 6个主要县、区 (扶风、武功、兴平、秦都、礼泉、乾县等 )的气象站均有较长系列的降水资料 ,可供我们进行用水、降水关系分析。分析三者之间的相关关系 ,并通过降水预报资料 (省、市气象台提供有年、季等中、长期天气预报 ,包括降雨量预报等 )预测灌区用水量。这对于编拟灌区用水计划、预算当年资金收入、安排工程项目、指导水库蓄水、水源调度等灌溉管理工作、扩大灌溉效益等 ,有着重要意义     

党河灌区地下水动态及开采优化分析

针对近年来党河灌区地下水资源的过度开采造成严重生态环境问题的现状,在分析该区地下水变化特征的基础上,重点开展地下水开采的优化分析研究。主要通过水位约束、水量约束、生态环境约束三个方面,建立相应的控制方程,对地下水资源的数量、质量、时空分布特征和开发利用条件作出科学全面的分析和估计。结果表明:根据"地下水快速下降区内机井全部关闭、地下水缓慢下降区内机井部分关闭、基本稳定区机井保持现状、月牙泉周围1 km范围内机井全部关闭"的原则,提出了各乡镇灌溉机井的配置方案,全灌区灌溉机井数量由2009年的2 571眼压减到2015年的1 041眼和2020年的868眼,并提出不同乡镇的地下水优化开采量。     

疏勒河流域中下游土地覆盖动态变化及其与地下水的相关性研究

本文以河西走廊疏勒河流域中下游区域为研究区，研究该地区土地覆盖动态变化及其与地下水的相关性。利用2000~2008年每年8月份的MOD13Q1数据及2000年的ETM+遥感影像数据，采用监督分类技术，对研究区不同时期的土地覆盖进行了划分，对比分析了两个不同时期（2000~2004年和2004~2008年）的土地覆盖变化。结合研究区昌马灌区地下水监测资料，建立植被指数与地下水埋深的Pearson相关模型，计算了植被指数和地下水埋深相关系数。通过分析表明，对于不同地下水的埋深区间和不同的土地覆盖类型，相关系数具有一定差异，天然植被与地下水埋深有较大的相关性。     

库水波动下库岸边坡地下水浸润线解析解及误差分析

解析法是库岸边坡地下水浸润线计算中便于实际应用的方法,但该方法须基于若干假定并对潜水运动基本方程线性化后才能求解。针对各假定和线性化过程建立不同的地下水渗流数学模型,用解析法和有限元法解答上述数学模型,分析各误差大小及其规律。结果表明：库岸垂直处理带来的误差要小于方程线性化处理和不考虑非饱和渗流带来的误差,而且它们都随渗透系数变大而减小;在三峡库区库水调度情况下,假定库水位等速变化带来的误差对大多岸坡而言可以忽略;计算库岸边坡地下水浸润线时,解析法只适用于水位变化幅度相比含水层厚度较小,且几何边界规则、岩土结构简单、岩土体渗透性较好时的情况。     

那陵郭勒河冲洪积扇地表水—地下水转化关系

通过分析那陵郭勒河冲洪积扇地区地表水与地下水的氢氧稳定同位素特征,揭示冲洪积扇地区不同地带的地表水—地下水转化关系。研究结果表明:冲洪积扇地区地下水主要补给来源是南部山区的大气降水和冰雪融水。河水与地下水具有同一起源,且二者相互转化,在冲洪积扇地区不同地段表现出不同的转化方式:上游山区河水与地下水水力联系较弱;中游山前隆起带地下水补给河水;下游冲洪积扇中部河水补给地下水;在冲洪积扇前缘溢出带,河水主要由地下水溢流形成的泉水汇流而成。     

Evaluation of Reanalysis Precipitation Data and Potential Bias Correction Methods for Use in Data-Scarce Areas

Water Resources Management - Data availability and accessibility often present challenges to resolving regional water management issues. One primary input essential to models and other tools used...