含水层试验参数计算及有效性检验的雅各布（Jacob）新方法

含水层试验分析的雅各布直线法，通常假定：①数据位于水位降－时间半对数曲线的直线段；②无量纲时间因子小于０．０１和③含水层文地质条件符合雅各布法的假定和限定条件。它要求抽水井半径尽可能小，并采用后期试验数据进行分析。对于前两项雅各布一般满足，但第三项常补忽视，导致含水层参数计算有误，雅各布改进方法则考虑了上述不足之外，它首先对原始时间－水位降数据进行分析，舍弃不合格数据，进而用雅各布直线法进行分析，     

含水层试验参数计算及有效性检验的雅各布（Jacob）新方法

含水层试验分析的雅各布直线法，通常假定：①数据位于水位降──时间半对数曲线的直线段；②无量纲时间因子小于０．０１和③含水层水文地质条件符合雅各布法的假定和限定条件。它要求抽水井半径尽可能小，并采用后期试验数据进行分析。对于前两项雅各布法一般满足，但第三项常被忽视，导致含水层参数计算有误。雅各布改进方法则考虑了上述不足之处，它首先对原始时间──水位降数据进行分析，舍弃不合格数据，进而用雅各布直线法进行分析，求出导水系数和储水系数，然后再将时间──水位降数据转换成无量纲单元，求出参数值，以判断雅各布直线法是否满足当地的水文地质条件。     

150型水井钻机在混凝土井柱桩钻筑中的应用

150型水井钻机已被广泛应用于中小型水工建筑物混凝土井桩桩钻筑施工中，代替了双开钻入工钻筑混凝土井柱极的原始施工方法，取得了较好的效果：一是提高了混凝土井桩桩的质量；二是加快了施工进度，提高了成孔率与工效；三是可以节省人力，降低费用，减轻了施工人员的劳动强度。150型水井钻机平均每台班钻筑混凝土井柱拉玛m，比使用双开钻人工钻筑混凝土井桩桩提高2．5倍；成孔率达95％，比双开钻提高朋％。一、主要设备及在桩基中的应用150型水井钻机系散装回转式转盘水井钻机，有主机（包括卷扬机、转盘、传动器）、塔架、钻杆、钻具、高…     

鄱阳湖口水位流量关系研究

水文站的水位流量关系变化反映了江湖之间的相互作用，为探究长三峡工程投运后长江与鄱阳湖的相互影响，分析了九江与湖口站的水位流量关系，基于考虑回水顶托作用的水位流量关系，建立了九江、湖口水位流量计算方法。研究表明：三峡工程投运后，九江站水位流量曲线下移，多年平均水位较三峡建库前降低0.8 m，综合线低水位区域也逐年下移，受九江水位降低影响湖口站平均水位降低0.7 m，三峡工程对长江干流的影响范围在大通以上，长江对鄱阳湖的顶托作用减少1.1%；基于前人成果，研究了湖口流量计算方法，2003-2021年资料拟合的计算公式精度达到86%，建立了湖口水位流量关系曲线，提出了湖口倒灌判别关系，当九江与五河流量之差超过30 000 m3/s时可能发生长江水倒灌鄱阳湖，研究成果为长江与鄱阳湖顶托关系分析提供了一定借鉴。     

沉降中心减采对北京平原地下水利用的影响分析

【目的】研究沉降中心减采对北京平原地下水利用的影响。【方法】采用非稳定流地下水模型和情景分析的方法,通过设计4个情景(现状保持(情景BAU)、沉降中心完全停采(情景PR100)、沉降中心减采50%(情景PR50)及沉降中心不同地区减采不同比例(情景PR520))模拟了地下水减采的影响。【结果】预测期内平均来说,情景BAU消耗1.16亿m3/a的含水层储存量,而情景PR100、PR50和PR520的储存量恢复分别为3.52亿、1.18亿和2.83亿m3/a。设计满足控沉目标的情景R:八仙庄、天竺和王四营用于工业和生活的地下水分别减采0.51亿、0.12亿和1.76亿m3,总开采量19.28亿m3,R是满足地面沉降控制要求条件下北京平原应采取的开采情景。【结论】沉降中心减采能有效恢复北京平原地下水水位和含水层储存量,是解决北京市地下水严重超采及其带来的地面沉降等生态环境问题最直接有效的方法,但要合理确定减采的比例,保证社会经济和地下水的协调发展。     

县城电网改造的探索与实践

1供电负荷预测负荷预测是城同规划设计的基础。我们尝试采用分区、分类的预测方法，即老城区与经济开发区分开预测；行业用电分类预测。老城区可依据历年负荷资料，对生活用电及一些增长曲线平滑的行业用电可运用回归分析等外推方法预测规划期负荷，再以历年实际递增率作校校；对一些随市场经济发展出现起伏的产业，通过经济部门了解相关市场情况及其演变趋势，推测其在规划期内负荷变化情况，这样预测的规划期负荷还是比较接近实际的。对经济技术开发区的负荷预测主要采取单位负荷密度法，一般在20MW／km左右。所以对经济技术开发区的负荷…     

氯离子示踪法在河北平原地下水垂向入渗补给量评价中的应用

采用氯离子示踪技术确定干旱一半干旱地区地下水垂向入渗补给量对于揭示地下水补给的空间变化规律，完善地下水资源评价的理论与方法，具有重要理论与现实意义。利用天然环境氯离子示踪法评价了河北平原典型区地下水垂向入渗补给量，结果表明该方法在山前冲洪积平原水位埋深大的淡水区应用效果较好，鹿泉和栾城的补给量分别为44．72mm／a和31．31mm／a，占多年平均降雨量的8．2％和5．8％，以扩散流入渗为主；在中部冲湖积平原和滨海冲积海积平原由于天然环境氯离子浓度背景值高、水位埋深浅以及近海输入氯离子的波动性较大，该方法的应用受到一定程度的限制。     

基于ELM模型的浅层地下水位埋深时空分布预测

选用石家庄平原区补排因子的多种组合为输入参数,利用28眼水井的实测资料作为预测目标值,首次建立基于极限学习机(Extreme learning machine,ELM)的地下水位埋深时空分布预测模型,讨论补排因子在不同缺失情况下对模型精度的影响;利用Arc GIS分析误差空间分布趋势,并与常用的三隐层BP神经网络模型进行对比。结果表明:基于水均衡理论的ELM地下水位埋深模拟模型能够准确反映人类和自然双重影响下地下水系统的非线性关系,模型输入因子中缺失降水量或开采量的模拟结果均方根误差(RMSE)比缺失其余因子的RMSE高2.00倍及以上,同时模型有效系数(E_(ns))和决定系数(R~2)进一步降低;与BP模型相比,ELM模型可使RMSE减小43.6%,误差区间降低46.4%,Ens和R2提高至0.99,且RMSE在空间相同区域上均明显呈现出ELM模型小于BP模型;ELM模型在南部高误差区的移植精度(RMSE低于1.82 m/a,E_(ns)高于0.95)高于BP模型(RMSE超过3.00 m/a,Ens低于0.85);因此,影响地下水位埋深的主导因素是降水量和开采量,且ELM模型在精度、稳定性和空间均匀性上较优,移植预测效果较好,可利用已知资料推求区域空间内其余未知水井的浅层地下水位埋深;该模型可作为水文地质参数及补排资料缺乏条件下浅层地下水位埋深预测的推荐模型。     

灌区量测水方法与技术研究进展

精准的灌区量测水方法与技术是减少灌区无效弃水，保障灌区用水安全的重要手段。针对灌区明渠量测水方法与技术，系统阐述了水工建筑物量水、特设量水设备量水、流速—面积法量水和水位—流量法量水4种方法的研究进展，归纳分析了4种量测水方法的适用条件及量测精度，阐述了不同场景下明渠量测水方法应用情况。结果表明：配备水位传感器等设备的量水建筑物为数据获取与传输提供了便利；优化建筑物结构特征可提升建筑物适用范围和测量精度，推动了特设量水设备技术发展。流速—面积法因量测精度高常用于校准其他量测水方法，但其操作复杂、耗时长导致测流效率较低，随着超声波等技术日趋成熟，可用以复杂流态流量的测量工作；流速分布规律作为流速—面积法量水的基础，利用流速分布规律可建立点流速与断面平均流速的关系，进而通过点流速获取断面流量。水位—流量法受断面参数影响显著，仅对特定工况可用，因此难以推广。利用机器学习方法处理大量水位与流量关系的历史数据对水位预测流量提供了数据处理手段。最后，探讨了非接触式量测水技术以及模型算法对流量预测的发展前景，结合目前研究基础和实际需求对未来的研究方向进行了讨论，以期为进一步提高量测水精度、降低量测水...     

基于实数遗传算法的农机总动力变权组合预测

黑龙江省农机总动力进行预测,选用指数函数模型、多项式拟合模型、三次指数平滑模型、龚帕兹曲线模型为单一预测模型并以1980-2013年农机总动力数据为样本点进行拟合,其平均绝对百分比误差分别为12.5%、3.22%、3.43%、6.09%;然后,建立以误差平方和最小为目标函数的变权组合预测模型,并利用改进的实数遗传算法对变权组合预测模型进行优化,所得到的变权重组合预测模型的平均绝对百分比误差为1.98%,拟合效果较好。以2014-2016年农机总动力数据为预测时点对该方法进行验证,结果表明:不论是拟合精度还是预测误差都具有较好的效果。最后,对黑龙江省未来5年的农机总动力进行了预测,为相关部门对农业机械化的发展规划提供参考。     

Estimating potential costs and gains from an aquifer storage and recovery program in Australia

Artificial recharge of aquifer storage can provide water during drought periods, reverse falling groundwater levels and reduce water losses associated with leakage and evaporation, as compared with surface water storage. We examine the technical and economic potential of artificial storage and recovery for drought mitigation in the Murrumbidgee Region of New South Wales, Australia. Potential locations for infiltration basins and injection/recovery wells are identified according to criteria such as water availability, aquifer suitability, recharge potential, and potential to provide a usable resource. The estimated annual artificial recharge potential is 180,000 ML through a combination of injection wells and infiltration basins. The cost estimates for artificial recharge vary from AU$ 62 ML⁻¹ to AU$ 174 ML⁻¹ depending on the choice of recharge method. Underground storage capacity can be developed at less than half the cost of surface storage facilities without undesirable environmental consequences or evaporation losses. The estimated benefits of artificial storage and recovery through infiltration basins are three to seven times the costs, during low allocation years.     

Diagnostic Analysis of Farmers' Skimming Well Technologies in the Indus Basin of Pakistan

Farmers are using skimming wells tosupplement their canal deliveries. Toensure sustainable groundwater extraction,proper design and operational guidelinesfor these skimming wells are required. Thestarting point of such guidelines is tolook at farmers' existing groundwaterextraction practices, their extent andassociated problems. For this purpose, afield survey was conducted in the IndusBasin of Pakistan. Participatory ruralappraisal identified several design andoperational problems with farmers' skimmingwells. These include; depth of well,number of strainers, horizontaldistance of strainers, priming, water quality, sand in pumped water,and reduction in well discharge withtime. To investigate these problems,diagnostic analysis was carried out. A testborehole was drilled to get water samplesalong the aquifer depth during drilling.The depth of well was then decided on thebasis of these water quality analyses. Todecide the number of strainers, a pumpingtest was conducted at test borehole toestimate the contribution of individualstrainer and then the numbers wereincreased according to the desireddischarge. Similarly, placing non-returnvalve between blind pipe and strainersolved the priming problem. Operating wellsintermittently rather than continuouslysolved the problems of water quality andreduction in well discharge. The systematicapproach adopted in the study helped thefarmers to rectify the problems.     

叶轮后密封环直径加大量对轴向力特性的影响

以300QJ230-40/2型潜水泵为研究对象,以清水为介质,采用标准k-ε湍流模型在多重参考系下对该泵全流道进行了定常不可压数值模拟,获得了外特性和轴向力预测值,并绘制了性能曲线和轴向力随扬程变化的关系曲线;采用机械法对该泵轴向力进行了试验测量,并将模拟值与试验值进行对比分析.结果表明:在0.8Q_sp~1.2Q_sp(对应扬程为46~36 m)的工作区域,泵性能和轴向力的数值计算结果与实测结果基本吻合.在叶轮前密封环直径、平衡孔直径及数量不变的条件下,在叶轮后密封环直径加大量Δr_m≠0时,对该潜水泵进行了全流道数值模拟和轴向力数值计算,绘制了不同后密封环直径下泵轴向力随扬程变化的关系曲线,结果表明了加大后密封环直径能有效地减小轴向力;绘制了轴向力系数与比面积关系的无因次曲线.     

Hydraulic and hydro-salinity behavior of skimming wells under different pumping regimes

Skimming wells are meant to extract top fresh water layer in the fresh-saline aquifer. Their development in the Indus basin occurred through private sector in a technological vacuum. As a result, these wells have some technical, environmental and social constraints, which hinder the sustainability of these wells. As an initial step to improve the well technology, the hydraulic and hydro-salinity responses of the fresh-saline aquifer under different pumping regimes need to be monitored. The present paper reports the hydraulic and hydro-salinity behavior of the Indus basin aquifer in Pakistan under field conditions at farmers’ wells. Two sites, having 6- and 16-strainer wells were monitored during July 2000–December 2001. The 6-strainer well was operated for 4 h with single-, 4- and 6-strainer arrangements and the spatial behaviors of specific drawdown were observed under these arrangements. The 16-strainer well was monitored continuously for the above period. The well discharge, pumped water quality and pumping duration was recorded of every pumping event under farmer’s practice to extract groundwater. The rainfall and temporal water table fluctuation was also recorded at this site. The impact of 24 years of well operation on groundwater quality was observed by comparing the hydro-salinity profiles of 1974 and 1998 under 3-strainer well. The results showed that the specific drawdown was higher for single-strainer and it decreased with the increase in number of strainers in skimming wells and hence reduced the chances of saline-upconing. Each strainer in multi-strainer well contributes equally in well discharge provided the horizontal distances among the strainers are equal. The pumped water quality in fresh-saline aquifer was a very sensitive function of fresh water recharge and pumping duration. It was observed that with the increase in daily operation from 2 to 12 h per day, the pumped quality deteriorated three-folds and there was also 30% reduction in well discharge due to high suction lift. It was observed that continuous operation of a 3-strainer well having discharge of 14 lps over the 24 years had raised the fresh-saline interface (iso-concentration line of 1.5 dS/m) to 9 m. Keeping in review the observations, it is recommended that the daily operation of 4–6 h keep the water quality within marginal limit (<1.5 dS/m) and the pumping operation is also cost-effective with only 15–20% reduction in well discharge for the study area.     

用抽水资料推求取水半径的试算法

分析了无上、下补给,井内定水位且初始水位呈水平时,均质含水层中的割离井渗流模型的出水量公式,引进了仅与相对井径(抽水井半径与取水半径之比)有关的函数,称其为割离井法的井流函数;对出水量公式进行数学变换,找到一条不含水文地质参数、仅与相对井径有关的理论曲线,该理论曲线也可由抽水资料获得。在该曲线上取2点,得到含有相对井径和另一参数的2个方程组,分析方程组的性质,采用试算法求解得到取水半径的值,最后用实例进行验证。     

Simulating skimming well techniques for sustainable exploitation of groundwater

The problems of saline water upconing and intrusion are of major concern in the Indus Basin of Pakistan. The withdrawals of fresh water overlying saline groundwater have resulted in inferior quality of pumped water and degradation of the aquifer. The continuous use of such qualitatively inferior water for irrigation has severely affected fertile lands causing agro-economic declination. Nearly 197 billion cubic meters (bm3) of fresh water has accumulated in the form of a thin layer over saline water, and over 20 bm3 of fresh water is being recharged annually in saline zones of the basin. In these situations skimming wells can play an important role in augmenting irrigation supplies and watertable control, as well as alleviating degradation of the aquifer. However, the working efficiency of skimming wells is not fully known. To investigate the effectiveness of various skimming wells, a density dependent finite element numerical model was modified and applied. In the present study an analytical equation was developed by gauging the effects of temperature and viscosity on the hydraulic conductivity of the porous media subjected to the saline water. The new equation was incorporated into the model. Simulations of flow and solute transport towards single, two-strainer, radial, compound and recirculation wells were performed. Physical modelling of such skimming well configurations was undertaken to calibrate the numerical model. The double-strainer well method performed better than the other skimming configurations tested in this study.     

Estimating groundwater withdrawals in areas of intensive agricultural pumping in central Spain

Measuring groundwater extractions is central to adequate groundwater management in agricultural basins. Groundwater pumping records are often subject to considerable uncertainties, particularly in the case of arid and semiarid settings where irrigation is the most important water use. In most cases this is due to the difficulties involved in locating and monitoring all wells. We describe the estimation of groundwater pumping by coupling the water table fluctuation method with the groundwater balance equation. This is demonstrated through its application to the Mancha Occidental aquifer, Spain, an area subject to intensive pumping for irrigation since the early 1970s. A sensitivity analysis is conducted to evaluate the effect of relevant hydrogeological parameters, namely specific yield, as well as the most appropriate theoretical semivariogram, to calculate yearly storage variations within the system. Results are validated in the light of official pumping estimates.     

A Markov chain approach to crop yield forecasting

This study proposes a methodology for forecasting crop yields at intermediate times in the growing season using Markov chain theory. A Markov chain is constructed, based on historical data, to provide forecast distributions of crop yield for various crop and soil moisture condition classes at selected times prior to harvest. Expected yield and the associated standard error are obtained for each condition class. The methodology is compared to a regression approach in which the independent variables are the various crop and soil moisture conditions. The Markov chain approach requires less stringent assumptions and provides more information than the regression approach. However, the potential loss of precision in the forecast using this approach requires separate evaluation for each application. A data base created by the CERES-Maize model, which simulates the growth and development of a corn crop, is used to demonstrate the development of the forecast yield distributions using the Markov chain approach.     

温室番茄结果期产量和品质对水分亏缺的响应

试验以甘肃武威市凉州区传统灌水量为对照(CK),设计3个灌水量水平CK、2/3CK、1/2CK,在番茄结果期研究亏缺灌溉对日光温室番茄累计产量及平均单果质量、品质、干物质分配及水分利用效率的影响。结果表明,随着灌水量的减少,水分利用率显著提高,番茄果实中的可溶性固形物、可溶性蛋白、有机酸和Vc含量均增加,果实的累计采收...     

深松对干旱牧区天然牧场牧草生长的影响

为了解决干旱牧区天然牧场的雨水利用效率低的问题,通过对天然牧场进行全方位深松来增加雨水的利用效率。结果表明,深松后牧场的土壤密度平均下降0.14 g/cm3,牧场牧草的株高和产量增长量都比对照组有明显增加,平均增长率分别比对照组高42.98％和215.6％;水利用效率也相应提高,株高和产量的水利用效率增长幅度分别为13...