共查询到20条相似文献，搜索用时 218 毫秒
1.
《中国农村水利水电》2016,(9)
获取府河下游数字高程图,确定府河及两岸地下水观测点,从2015年5月-2016年4月进行河水及两岸地下水观测,采用描述统计方法对观测结果进行逐月和季节的变异分析,建立了府河和浅层水观测井水质参数与时间关系曲线。结果表明:氨氮、亚硝酸盐和磷酸盐均为强变异性,硝酸盐为中等变异性;认为在非农业生产活动时期的冬春季节府河两岸浅层地下水水质主要受府河水质的影响,且地下水水质变化较府河水质有明显的滞后性;最后把氨氮、硝酸盐、亚硝酸盐作为评价因子使用单因子评价法对府河两岸地下水逐月进行水环境评价,得出除了1、2月份为Ⅳ级外其他月份均属于Ⅴ类水质。 相似文献
2.
近几年锡林河流域开始进入降水偏丰周期,但地下水“入不敷出”的情况愈加明显,过量的地下水开采需求只能通过消耗地下水储蓄量来实现。基于水均衡原理和统计学方法分析锡林河平原区地下水位对降水量和开采量间的响应程度。研究结果表明,各个观测井对降水时序变化的响应差异较大,其中饲草料基地井与农场三队井地下水位变幅对降水较为敏感;水位埋深与开采量之间存在明显的正相关关系,从水位-开采量关系曲线变化趋势来看,随着地下水开采量增加,农场三队、饲草料基地和奶牛场的水位响应最明显;农作物大棚种植区地下水位主要受降水量与开采量共同作用,响应程度为51.16%,而饲草料基地受开采量影响最大,达到60.71%,压减灌溉饲草料地规模、调整集中连片布局为分散式利用是缓解农灌区地下水超采、促进农牧业安全发展的主要途径。 相似文献
3.
通过选取宝鸡市区八大水源地多眼观测井1999年以来的动态资料,深入研究了宝鸡市自备井关闭前后地下水位动态变化规律,并利用线性回归法确定了宝鸡市区年地下水年开采量与平均水位埋深之间的相关关系。结果表明市区地下水开采是影响水动态的主要因素。最后得出结论：宝鸡市可以通过关闭（开启）自备井调控地下水位保持在合理的区间,进而改善地下水质,实现水资源持续利用以及水环境保护的和谐发展。 相似文献
4.
北京大兴区浅层地下水水质初步评价 总被引：4，自引：0，他引：4
采用模糊数学方法对大兴区82个浅层地下水监测井的水质进行了现状评价。结果表明，中西部水质较好，主要为Ⅱ类和Ⅲ类水，而北部、南部和东部大部分地区水质较差．主要为Ⅳ类和V类水。造成本区地下水水质污染的主要原因是过境污水的渗透、不适当的污水灌溉。 相似文献
5.
利用新疆吐鲁番地区2003年和2011年地下水质量与污染调查评价工作所取得的地下水水质数据,采用单因子评价法进行地下水质量评价,采用同一水井2003年和2011年化学组分浓度对比法进行地下水污染评价。地下水质量评价结果显示,2011年吐鲁番地区可以直接饮用(Ⅰ~Ⅲ类水)或经适当处理可以饮用(Ⅳ类水)的地下水水井占调查总井数(24眼)的58.33%,不能饮用的地下水(Ⅴ类水)占41.67%;影响地下水质量的天然化学组分主要为总溶解固体(TDS)、总硬度、SO2-4、Cl-、高锰酸盐指数等。地下水污染评价结果表明,地下水质量等级变差的水井占调查总井数(7眼)的42.86%,质量等级不变的占28.57%,质量等级变好的占28.57%。从原生环境和人为因素两个方面简单分析了吐鲁番盆地地下水质量总体较差和水质污染的原因。为遏制地下水水质恶化态势,有效保护吐鲁番盆地地下水资源与环境,提出了一些合理的建议。 相似文献
6.
《中国农村水利水电》2020,(9)
地下水资源对区域经济社会发展至关重要,而准确预测地下水埋深是合理利用地下水资源的重要依据。以陕西关中平原33眼地下水埋深观测井的实测数据为输入,探讨长短时记忆网络模型(LSTM)在地下水埋深模拟预测当中的应用。结果表明:整体上,LSTM模型可以很好模拟关中地下水埋深的变化,但是模型在训练阶段的模拟精度要高于验证阶段的。具体而言,对33眼观测井同时模拟时,无论训练次数多少,其决定系数(R~2)均大于0.98,而均方根误差(RMSE)和相对均方根误差(RRMSE)分别小于5 m和14%;而在验证阶段,尽管模拟值与观测值的R~2仍然大于0.98,但是RMSE和RRMSE的最大值分别增加至7 m和27%。与此同时,模型的训练次数会影响模拟精度,模型训练次数需要与样本进行匹配,本研究适宜的训练次数为40次。此外,样本集的数据也是影响模型模拟准确度的关键因素,将33眼井的观测数据作为一个样本集的模拟精度要高于单眼井单独作为样本集的模拟精度,表明样本容量越大,LSTM的模拟精度越高。 相似文献
7.
【目的】探究北京市昌平区不同层位地下水埋深时空动态特征及其对降水的响应。【方法】基于2021—2022年北京市昌平区98处地下水自动监测井(浅层井75处、深层井16处、基岩井7处)的实测地下水埋深数据及降水观测数据,结合克里金插值法和Cross-correlation方法,分析了昌平区不同层位地下水埋深的空间分布、时间动态变化及其对降水的响应。【结果】昌平区地下水埋深的空间分布整体为东南部较高,西北部较低。浅层地下水埋深在2个观测年度均存在1处降落漏斗,深层地下水在2021年存在1处降落漏斗,但于2022年消失,基岩地下水埋深无降落漏斗。深层地下水埋深分布的空间变异性明显高于浅层和基岩层;浅层地下水和深层地下水在各月呈同步增长或下降趋势,埋深最大值分别出现在2021年6月和2022年5月,最小值出现在2021年12月和2022年12月。基岩地下水埋深的月变化规律与浅层及深层相比具有明显差异,月尺度上不同层位地下水埋深整体表现为基岩层>深层>浅层。【结论】2021年的地下水埋深整体高于2022年,这与降水量的年际变化有关;不同层位地下水对月降水量的响应不同,其中基岩地下水埋深... 相似文献
8.
根据克孜勒苏4年的地表水、地下水、排水水量和水质等水盐监测动态资料分析及计算可以看出,项目工程实施后,排水能力加强,随着项目区的排水渠的疏通和开挖,排水量增加,相应的排盐量也在增加,监测区发生了由总体积盐到总体脱盐的变化,项目工程发挥了盐碱地改良的效果。为该地区灌区农业水盐分布规律及时空变化状况提供基础数据。 相似文献
9.
辐射井是开发浅层地下水的理想井型。针对银北灌区的水文地质条件。阐述了在银北灌区利用辐射井技术开发浅层地下水的设计方法，如竖井结构、井深设计、水平辐射管设计及涌水量计算等。并对成井技术、试验井的水量和水质等进行了探讨。 相似文献
10.
地下水动态长期观测是一项服务于工农业生产的基础性工作。本文应用概率统计及变异分析等理论,对实测的地下水位时间序列进行了分析,认为对于那些用于监测区域地下水动态的长期观测井,用人工定时观测的时间周期由现行的5天加大至10天,仍能满足生产上监测地下水位的要求。由于各地区水文地质条件不同,各种不同目的观测井精度要求不同,本文提出了一种选择合适的最小观测间隔的方法。 相似文献
11.
灌区土壤盐渍化发展模拟预测与对策研究 总被引：8，自引：0，他引：8
以秦王川灌区观测和调查资料为依据,采用目前广为实用的MODFLOW地下水模拟软件,对灌区地下水动态进行了预测和分析,并对地下水质的发展趋势作出评价。灌溉实施以来,秦王川灌区地下水位逐年上升。未来10年内盐沼区面积扩大约为28 km2,并且将继续增加,地下水埋深0~2 m的面积达31.4 km2,占灌区面积的比例约为6%。未来20年地下水埋深0~2 m的面积达47 km2,占灌区面积的比例为10%左右。根据地下水位的变化特征,对控制土壤盐渍化发展的因素和对策进行了分析,提出以明沟排水为主,加大灌区下游地下水排泄能力;以渠灌为主,适度发展井灌,大力推行田间节水灌溉技术等对策。 相似文献
12.
对新疆盐碱地排碱渠渠水、水渠水、井水和塔里木河水水样进行了分析:其总盐量分别为12 915、11 352、9 980、1 421mg/L,根据水质评价标准当地水样主要有害盐分离子为Na+、Cl-,除塔里木河水外其他水样含盐量均严重超过了农业灌溉用水标准,未经任何处理的高盐农业废水对地下水体和公共水体都造成了一定的盐污染。对比分析各种水除盐方法,初步讨论采用价格低廉且具有良好选择吸附性能的钙基膨润土作为吸附剂对3号水样(水渠水:盐度为11 352mg/L)进行除盐。在固定温度50℃、搅拌速度为0.75m/s、吸附剂用量为5g(每100mL水样),搅拌1h后静置1d,总盐量降幅为23%,Na+浓度降幅为32%。此实验结果对高盐农业废水的再利用具有重要参考价值。 相似文献
13.
干旱区灌排条件下田间土壤盐分动 总被引：3，自引：0，他引：3
根据干旱地区实测的田间土壤含盐量、地下水埋深和矿化度以及灌溉量，分析了土壤盐分的时间动态变化及空间分布特征，确定了土壤盐分与地下水矿化度的线性正相关关系，建立了土壤盐分与地下水埋深和矿化度的统计模型。 相似文献
14.
《Agricultural Water Management》2004,69(1):43-67
A trial was conducted to examine the effects of retaining drain water with a weir on reducing acid flux from a drained coastal acid sulphate soil backswamp. Prior to weir construction, groundwater seepage to the ditch drain was the main hydrological pathway for acid flux. High hydraulic conductivity (>120 m per day) in the sulphuric horizons due to extensive macropores, combined with tidal modulation of drain water levels encouraged rapid seepage of acid groundwater. Most seepage occurred while the backswamp groundwater table was in a narrow elevation range, referred to as an ‘acid export window’. The acidity of drainage water was highly sensitive to the hydraulic gradient between the groundwater table and the adjacent drain water level. Acid flux rates from groundwater seepage were strongly positively correlated to effluent groundwater hydraulic gradients. The constructed weir was designed to reduce the magnitude of effluent groundwater gradients and retain shallow groundwater by maintaining high and stable drain water levels. This reduced groundwater seepage to the drain and increased the proportion of shallow groundwater lost from the system via evapotranspiration. The weir affected 60% of drainage network and observed and modelled data suggest acid flux from groundwater seepage was reduced by about 65–70%. Effluent groundwater gradients behind the weir were reduced by about 80%. The main effect of the weir was to reduce discharge volumes, although reductions in H+ and acidic metal cation concentrations were also observed. This study demonstrates that a weir can be an effective means of reducing acid flux in coastal acid sulphate soils where main hydrological pathway of acid export is groundwater seepage. However, this strategy may not prevent continued sulphide oxidation. Reduced acid export, but continued acid generation, combined with enhanced evaporative flux has the potential over the longer term to increase the net accumulation of acidic products in the backswamp soil and groundwater. Further monitoring is required to assess this possibility. 相似文献
15.
《Agricultural Water Management》2005,73(2):87-111
Periodic opening of one-way tidal floodgates was undertaken on two coastal flood mitigation drains to promote exchange with estuarine water and improve drain water quality. The drains were located in areas with acid sulphate soils and their drainage water frequently had high acidity and low dissolved oxygen (DO). Tidal exchange via floodgate opening generally raised drain water pH levels through dilution and/or neutralisation of acidity. Increases in DO and moderation of extreme diurnal DO fluctuations were also observed. The magnitude and stability of the improved physico-chemical conditions was highly dependant on the volume and quality of tidal ingress water. Relatively rapid reversion (hours to days) in drain water pH and DO was observed once floodgates were closed again. The rate of reversion following floodgate closure was strongly related to outflow volumes, antecedent drain water quality conditions and groundwater levels. Floodgate opening caused changes in longitudinal drain water gradients and has potential to slow net drainage rates during non-flood periods. However, complex site specific interactions between drain water and adjacent groundwater can also occur. At one location, a 4-day floodgate opening event caused recharge of adjacent acid groundwater during the opening phase, raising the potentiometric groundwater level above local low tide minima. This was followed by tidally modulated draw down of acid groundwater and enhanced acid export in the period immediately following floodgate closure. There are also practical considerations, which limit the efficacy of floodgate opening as an acid management strategy. The low elevation (close to mean sea level) of some acid sulphate soil backswamps, combined with seasonal migration of the estuarine salt wedge, means there is considerable potential for saline overtopping of what is currently agricultural land. This constrains the magnitude and duration of controlled tidal exchange. Also, it is during wet periods that acid drainage outflow to the estuary is greatest. At such times the salinity and acid buffering capacity of estuarine water is often low, thus reducing the capacity of tidal exchange waters to neutralise acidity. 相似文献
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Salinity dynamics of wetland ditches receiving drainage from irrigated agricultural land in arid and semi-arid regions 总被引：1，自引：0，他引：1
Agricultural drainage ditches are considered as wetland ecosystems when they possess the characteristic hydrology, soil and vegetation of wetlands. In arid and semi-arid regions, wetlands receiving agricultural drainage have to cope with the conservative nature of salts leached from soils. Excessive accumulation of salts in wetlands may threaten the ecological functions of the system, thus endanger the sustainability of the drainage disposal system and the productivity of the farmlands. Based on the salt and water balance in a farmland drainage and wetland disposal system in arid regions, this paper presents a thorough investigation on salinity dynamics of wetland ditches receiving agricultural drainage. Theoretical equations were derived to describe salinity changes in water and soils of wetlands under both equilibrium and pre-equilibrium conditions; a case example was then used to display model predictions of salinity variations over time under different salinity management goals. The example wetlands are de facto drainage ditches that possess wetland characteristics, and the ditch to farmland area ratio is 9.1%. The results showed that salt as a conservative substance will eventually concentrate in the ditches to a very high level if there is little outflow discharge; but the salt accumulation process may develop over a relatively long time, which opens a time window for management practice, such as flushing the salts when fresh water is available. By assuming different threshold salinity levels in the ditches, the proposed analytical models were used to predict time intervals when fresh water recharge is needed to bring down the salinity level in the ditches. For the study area under current drainage practice, the predicted outflow to inflow ratio for salinity was 58.2% and reached an equilibrium level of 9.60 g L−1 in the ditches; salinity levels in the ditches reached threshold values of 5, 7 and 9 g L−1, in about 1, 4 and 12 years, respectively. Salinity analysis showed that the salt retention capacity of the ditch soil is limited, the soil salinity varied according to the ditch water; salt removal through plant uptake and harvest was insignificant. This study indicates that although salt concentration in wetlands receiving agricultural drainage may eventually build up to a critical level, timely recharge with fresh water may bring down salt content in the wetlands and sustain adequate environmental and ecological functions of such a drainage disposal system in arid and semi-arid regions. 相似文献
19.
Disposal of saline drainage water is a significant problem for irrigated agriculture. One proposal to deal with this problem is sequential biological concentration (SBC), which is the process of recycling drainage water on increasingly more salt tolerant crops until the volume of drainage water has been reduced sufficiently to enable its final disposal by evaporation in a small area. For maximum effectiveness this concept will require crop water reuse from shallow groundwater. To evaluate the concept of sequential biological concentration, a column lysimeter study was used to determine the potential crop water use from shallow groundwater by alfalfa as a function of ground water quality and depth to ground water. However, lysimeter studies are not practical for characterizing all the possible scenarios for crop water use related to ground water quality and depth. Models are suited to do this type of characterization if they can be validated. To this end, we used the HYDRUS-1D water flow and solute transport simulation model to simulate our experimental results. Considering the precision of the experimental boundary and initial conditions, numerical simulations matched the experimental results very well. The modeling results indicate that it is possible to reduce the dependence on experimental research by extrapolating experimental results obtained in this study to other specific sites where shallow saline groundwater is of concern. 相似文献
20.
塔里木灌区棉田的水盐动态和水盐平衡问题探讨 总被引：9，自引：0，他引：9
利用2004年在极端干旱的塔里木盆地绿洲棉田灌溉试验数据,对常规地面沟灌和膜下滴灌棉田在不同灌溉定额下水盐动态进行了研究,对节水灌溉与农田水盐平衡问题进行了深入探讨。主要结论包括:①在2700m3/hm2灌溉定额时,常规地面沟灌和膜下滴灌棉田在生育期0~60 cm土层积盐,膜下滴灌的积盐率(12.4%)要高于常规地面沟灌的积盐率(3.4%);②在小于6000 m3/hm2的4种不同灌溉定额条件下,生育期棉田1 m土体上总体表现为积盐;③对于土壤初始含盐量高的新垦荒地,灌溉淋洗的作用要好于土壤盐分本底值低的土壤;④为了保持农田的水盐平衡,在极端干旱区需要进行非生育期以淋洗盐分为目的的灌溉。 相似文献