共查询到20条相似文献，搜索用时 31 毫秒
1.
《Journal of Arid Environments》2006,64(4):756-771
This study was carried out in the Cuenca de la Independencia, a semi-arid basin in Central Mexico. The objective is to describe the main features of a groundwater flow regime under natural conditions, based on groundwater discharge manifestations. Information obtained from paleoecological, paleontological, archaeological and historical data suggests that, prior to heavy development (starting in the 1950s), the hydrogeologic regime was characterized by a larger groundwater availability in a more humid and colder climate. Manifestations associated to groundwater discharges are springs, lagoons, wetlands, saline soils, chalcedony deposits, phreatophytes, thermalism, and artesianism. The different types of manifestations and their position in the basin indicate the influence of groundwater flow systems hierarchically nested, forming concentric zones at ground level. The groundwater flow regime corresponds to a classical gravity-induced flow system with generation of local, intermediate and regional patterns. Integrating several types of data to establish the flow geometry and its dynamics has proven a useful tool to increase understanding of the original groundwater regimes. This approach can also be applied in other over-exploited semi-arid basins. 相似文献
2.
地下水补给量反映了含水层的可更新能力,是地下水资源管理与合理开发利用的关键参数之一。为定量研究黄土高原丘陵沟壑区小流域地下水的补给特征,基于岔巴沟流域上游、中游、下游3个水文站1959-1969年降水与日径流观测资料,通过退水分析法估算了流域地下水补给量,并分析了与降水量和基流量的关系及其在年内的补给变化过程。结果表明：岔巴沟流域年平均基流量为13.09 mm·a-1,更新时间为124 d,补给量为11.46 mm·a-1,降水入渗补给率为0.025,基流补给率为0.89。从上游到下游地下水补给量与入渗补给率逐渐增大,且上游与下游之间有显著差异（P<0.05）;基流补给率逐渐减小,各集水区之间差异均显著。地下水补给量与降水量呈线性正相关（R2>0.40）,在下游集水区内随降水量变化的增幅较大。基流量与降水量也呈正相关关系（R2>0.77）,干流基流80%以上源于降水补给转化。以5月份为节点可将地下水补给过程分为"一次补给"和"二次补给"2个主要阶段,其分别占全年总补给量约30%和70%,并且"二次补给"是造成岔巴沟流域不同集水区地下水补给量差异的主要阶段,并且为无资料地区小流域地下水资源的评价提供借鉴。 相似文献
3.
SWAT在干旱半干旱地区的应用——以窟野河流域为例 总被引：16，自引：1，他引：15
SWAT是一个基于物理机制的分布式流域水文模型,其产流机制中对于地表径流、壤中流、浅层地下径流和深层地下径流的模拟方法比较实用,能够适用于不同气候条件和下垫面条件下的产汇流情况.本文将SwAT应用到黄河中游干旱半干旱区多沙粗沙典型流域之一窟野河流域,模拟了1980～1985年的日流量和月平均流量过程,分析并探讨了SWAT产流机制对水源划分和径流形成过程的影响.结果表明,水量平衡相对误差在10%～20%左右,但Nash-Sutticliffe效率系数都较低.本文对模拟结果进行了初步分析,认为SWAT产流机制不能有效模拟干旱半干旱地区的窟野河流域的壤中流、基流和春汛流量过程,并探讨了SWAT在干旱半干旱地区产流模拟可能存在的问题和值得深入研究的方向. 相似文献
4.
Water is a primary controlling factor for economic development and ecological environmental protection in the inland river basins of arid western China. And it is groundwater, as the most important component of total water resources, that plays a dominant role in the development of western China. In recent years, the use-ratio of surface water has been raised, the groundwater recharge rate from surface water has been reduced, and groundwater has been exploited on a large scale. This has led to the decline of ground-water levels and the degradation of eco-environments in the Heihe watershed. Therefore, the study on the change in groundwater levels in recent years, as well as simulating and predicting groundwater levels in the future, have become very significant for im-proving the ecological environment of the Heihe River Basin, to coordinate the water contradiction among upper, middle and lower reaches of Heihe River Basin and to allocate the water resources. The purpose of this study is to analyze the groundwa-ter-level variations of the Ejina region based on a large scale, to develop and evaluate a conceptual groundwater model in Ejina Basin, to establish the groundwater flow model using the experimental observation data and combining Modular Three-Dimensional Groundwater Flow Model (MODFLOW) and GIS software, to simulate the regional hydrologic regime in re-cent 10 years and compare various water-delivery scenarios from midstream, and to determine which one would be the best plan for maintaining and recovering the groundwater levels and increasing the area of Ejina oasis. Finally this paper discusses the pos-sible vegetation changes of Ejina Basin in the future. 相似文献
5.
The Kent River flows from semi-arid headwaters in the agricultural (wheatbelt) region of Western Australia to a wetter and forested lower-catchment. It is set in an atypical fluvial environment, with rainfall decreasing inland towards a low-relief upper catchment. Replacement of native deep-rooted perennial vegetation with shallow-rooted seasonal crops has altered the hydrology of the upper catchment. Clearing for agriculture has also increased recharge of regional groundwater systems causing groundwater to rise and mobilise salt stores. This has increased stream salinity which has degradation riparian vegetation and decreased flow resistance. Elevated groundwater has also affected streamflow, increasing flow duration and annual discharge. The altered hydrological regime has affected geomorphic stability, resulting in channel responses that include incision and removal of uncohesive material. Channel response is variable, showing a high dependence on channel morphotype, channel boundary material and severity of salinity (degree of vegetation degradation). Response in confined reaches bounded by sandy material has been characterised by minor lateral bank erosion. In the fine-grained, wider, low-gradient reaches, mid-channel islands have been stripped of sandy sediment where vegetation has degraded. Following an initial period of high erosion rates in these reaches, the channel is now slowly adjusting to a new set of boundary conditions. The variable response has significant implications for management of salt affected rivers in southwestern Australia. 相似文献
6.
The morphometric and stratigraphic framework for estimates of debris flow incidence in the North Cascades foothills, Washington State, USA 总被引：1，自引：0，他引：1
Active debris flow fans in the North Cascade Foothills of Washington State constitute a natural hazard of importance to land managers, private property owners and personal security. In the absence of measurements of the sediment fluxes involved in debris flow events, a morphological-evolutionary systems approach, emphasizing stratigraphy, dating, fan morphology and debris flow basin morphometry, was used. Using the stratigraphic framework and 47 radiocarbon dates, frequency of occurrence and relative magnitudes of debris flow events have been estimated for three spatial scales of debris flow systems: the within-fan site scale (84 observations); the fan meso-scale (six observations) and the lumped fan, regional or macro-scale (one fan average and adjacent lake sediments). In order to characterize the morphometric framework, plots of basin area v. fan area, basin area v. fan gradient and the Melton ruggedness number v. fan gradient for the 12 debris flow basins were compared with those documented for semi-arid and paraglacial fans. Basin area to fan area ratios were generally consistent with the estimated level of debris flow activity during the Holocene as reported below. Terrain analysis of three of the most active debris flow basins revealed the variety of modes of slope failure and sediment production in the region.Micro-scale debris flow event systems indicated a range of recurrence intervals for large debris flows from 106−3645 years. The spatial variation of these rates across the fans was generally consistent with previously mapped hazard zones. At the fan meso-scale, the range of recurrence intervals for large debris flows was 273−1566 years and at the regional scale, the estimated recurrence interval of large debris flows was 874 years (with undetermined error bands) during the past 7290 years. Dated lake sediments from the adjacent Lake Whatcom gave recurrence intervals for large sediment producing events ranging from 481−557 years over the past 3900 years and clearly discernible sedimentation events in the lacustrine sediments had a recurrence interval of 67−78 years over that same period. 相似文献
7.
分布式时变增益流域水循环模拟 总被引：55，自引：0，他引：55
针对分布式水文模拟的问题,结合河西走廊黑河流域实际资料条件,提出将水文循环空间数字化信息与水文系统理论相结合的分布式时变增益水循环模型 (DTVGM)。DTVGM将单元时变增益水文非线性模型(TVGM)拓广到由DEM划分的流域单元网格上建立非线性地表水产流模型,基于水量平衡方程和蓄泄方程建立土壤水产流模型,并应用运动波方法建立分级网格汇流模型。最后,以黑河干流山区流域为例应用DTVGM开展了实例研究,设计开发了模型系统。研究区域被划分为38 277个网格单元 (网格大小为500 m×500 m),在此基础上将流域划分为456级带状汇流区域。考虑到黑河干流山区的寒区特点,模型耦合了融雪径流模型。模拟结果表明,DTVGM既有分布式水文概念性模拟的特征,同时具有水文系统分析适应能力强的优点,能够在水文资料信息不完全或者有不确定性干扰条件获得比较好的分布式水文模拟效率,在黑河干流山区的应用能够较好地满足水资源管理的要求。 相似文献
8.
黑河流域中游盆地地下水补给机理分析 总被引：14，自引：5，他引：9
分析地下水水循环机理是有效评价地下水资源量和合理开发利用地下水资源的前提。对此,利用皮帕尔（Piper）图解法分析地下水的水化学特征类型,结合区域构造水文地质和环境同位素,分析黑河中游盆地内不同地区的地下水补给机理。结果表明,位于黑河较上游地区两个相邻山前冲洪积扇之间的地下水水力联系微弱,分别来自于不同的补给来源;不同区域的黑河沿岸地区,受地理地形控制,地下水补给来源存在显著差异;以榆木山隆起相隔离的张掖盆地和酒泉盆地,地下水水化学特征和同位素存在显著差异,处于不同的地下水补给单元;利用放射性同位素氚含量,初步估算出不同地区地下水的更新期,其地下水年龄均低于32 a。为合理开发利用黑河中游地下水资源、保护脆弱的生态环境提供科学依据。 相似文献
9.
2017年在秦岭黑河流域7个采样点进行地下水样品采集。通过综合分析、Gibbs图、Piper三角图、主要离子比值法、主成分分析法得出黑河地下水化学成分的特点、水化学类型及其成因。结果表明：阳离子的主要组成成分是Ca2+，HCO3-是阴离子的主要组成成分，黑河流域地下水化学类型为HCO3-- Ca2+和SO42--HCO3--Ca2+型。Gibbs图分析得出该地下水化学离子组成受岩石风化作用控制；Piper三角图、主要离子比值法、主成分分析及相关分析表明，地下水化学组分主要受方解石、白云岩等碳酸盐岩矿物的风化溶解，同时伴有硫酸溶解碳酸盐岩，受硅酸盐岩的溶解控制作用较小。 相似文献
10.
Groundwater is a vital water resource in the arid to semi-arid southwestern United States. Accurate accounting of inflows to and outflows from the groundwater system is necessary to effectively manage this shared resource, including the important outflow component of groundwater discharge by vegetation. A simple method for estimating basin-scale groundwater discharge by vegetation is presented that uses remote sensing data from satellites, geographic information systems (GIS) land cover and stream location information, and a regression equation developed within the Southern Arizona study area relating the Enhanced Vegetation Index from the MODIS sensors on the Terra satellite to measured evapotranspiration. Results computed for 16-day composited satellite passes over the study area during the 2000 through 2007 time period demonstrate a sinusoidal pattern of annual groundwater discharge by vegetation with median values ranging from around 0.3 mm per day in the cooler winter months to around 1.5 mm per day during summer. Maximum estimated annual volume of groundwater discharge by vegetation was between 1.4 and 1.9 billion m3 per year with an annual average of 1.6 billion m3. A simplified accounting of the contribution of precipitation to vegetation greenness was developed whereby monthly precipitation data were subtracted from computed vegetation discharge values, resulting in estimates of minimum groundwater discharge by vegetation. Basin-scale estimates of minimum and maximum groundwater discharge by vegetation produced by this simple method are useful bounding values for groundwater budgets and groundwater flow models, and the method may be applicable to other areas with similar vegetation types. 相似文献
11.
鄂尔多斯市地处半干旱区,水资源缺乏,监测地下水位的变化对于地区生态和经济发展具有重要意义。本研究利用鄂尔多斯市6个地下水位监测井2005-2014年的监测资料,分析了该地区地下水位变化特征。结果显示:(1)本地区地下水位2005-2006年有所下降,2007-2010年逐年抬升,2011年受严重干旱影响,地下水位为近10年来最低值,从2012年开始至2014年,以每年0.14 m的幅度抬升,2014年为近10年最高值,地下水位的年际变化主要与煤炭开采和经济发展有关。(2)地下水位的年内季节变化明显,与降雨量、蒸发量和农业灌溉用水的相关性较高。3-7月,水位持续下降,7月地下水位为年内最低点;8-10月,水位逐步回升;11月至次年2月水位总体呈略微抬升状态,次年2月为年内最高值。 相似文献
12.
Role of fluvial and structural processes in the formation of the Wahiba Sands, Oman: A remote sensing perspective 总被引：1，自引：0，他引：1
C.A. Robinson F. El-Baz T.M. Kusky M. Mainguet F. Dumay Z. Al Suleimani A. Al Marjeby 《Journal of Arid Environments》2007,69(4):676-694
The Wahiba Sands in northeastern Oman are bordered on the north, south and west by highlands. Remote sensing data are used to characterize the region between 19–23.5°N and 56.5–60°E by mapping surface and near-surface drainage, faults and fractures and aeolian features. It is suggested that the sands were originally deposited with surface runoff from the principal wadis and fluvially reworked fault zones, which define the northeastern and southwestern margins. These fluvial processes resulted in the accumulation of the vast groundwater resources now stored there. During dry climates, wind became the principal modification regime and it began to sort and shape the sediments into the dune forms that characterize today's Wahiba region. The thickness of the sands reflects the depth of the basin in which they lie. The center of the basin is filled with the thickest sand (the High Sands) and contains the highest groundwater concentrations. Presently, aeolian reworking dominates in the Wahiba region, although the Low and the Peripheral Sands continue to experience some fluvial action from occasional, seasonal rainfall. Even though dry conditions dominate today, it is clear that similar to the Sahara of North Africa, the surface sands of the Wahiba basin are indicators of groundwater occurrence. 相似文献
13.
This work was designed to analyze the hydrogeological behavior of an alluvial aquifer in the River Mojotoro basin site in the Province of Salta, Argentina. The study area presents coarse-grained sediments with high infiltration capacity. The hydraulic conductivity field is affected by the physical heterogeneity of the medium and a geostatistical method, kriging, was used to construct this field from local measurements. The groundwater flow velocity field is computed using a hybrid mixed finite-element method and small variations in the flow directions were determined. Given the existence of a point source of chloride in the region under study, the spatial distribution of the generated plume in the saturated zone is analyzed. The advection-diffusion equation describing the transport of chloride in vertical and horizontal cross-sectional planes of the aquifer is discretized employing a method of characteristics combined with a mixed finite-element procedure, which provides an efficient method to eliminate spurious numerical oscillations and handle the convective term in the equation. The migration of chloride shows patterns, which are affected by the litologic heterogeneities of the aquifer and the regional groundwater flow. 相似文献
14.
泥石流的运动流型与流态是研究泥石流运动力学的重要内容。以云南东川蒋家沟泥石流运动观测为例,对阵流型、连续型、复合型三种流型及相应的流量过程特征进行了分析;借鉴水力学的流态理论,对天然沟遭中泥石流的流动状态(即层动流、波动流现象)进行了探讨分析,指出在一阵流动过程中也会出现几种不同流态特征。 相似文献
15.
16.
地下水埋深对半干旱区典型植物群落土壤酶活性的影响 总被引：1，自引：0，他引：1
土壤酶活性是反映土壤功能的关键指标,尤其在受到水分限制的半干旱区,土壤水分驱动的土壤酶活性生态功能的变化可以改变土壤养分周转并影响土壤碳质量。地下水埋深对半干旱区典型植物群落土壤酶活性的影响机制尚不明晰。以半干旱区科尔沁沙质草地两种典型植物群落（白草Pennisetum centrasiaticum和差巴嘎蒿Artemisia halodendron）为研究对象,开展地下水埋深模拟试验,地下水埋深分别为0.5、1.0、2.0 m。分析不同土层的土壤理化性质和土壤酶活性,探讨不同地下水位埋深深度下不同植被类型土壤酶活性的变化特征。结果表明：4种土壤水解酶（酸性磷酸酶（AP）、葡萄糖苷酶（βG）、乙酰氨基葡萄糖苷酶（NAG）和亮氨酸氨基肽酶（LAP））和2种氧化还原酶（过氧化氢酶（CL）和多酚氧化酶（POX））活性均受地下水位埋深和植被类型的影响。随着地下水埋深的增加,白草和差巴嘎蒿群落内土壤酶活性分别呈现不显著性和显著性的变化规律。同时,在各处理中土壤酶活性均随土层深度的增加而减小。地下水埋深对科尔沁沙质草地白草与差巴嘎蒿群落的土壤水解酶和氧化还原酶活性产生不同的影响。未来在半干旱区进行植被恢复时,建议考虑不同植物群落对地下水位变化的适应对策的差异,以更好地恢复半干旱区植物群落的地上地下生态系统功能。 相似文献
17.
《The Australian geographer》1995,26(1):71-86
The upper Nepean River has been progressively regulated for water supply to Sydney and Wollongong since 1886 by the Upper Nepean Water Supply Scheme which consists of four large dams, two small dams and two diversion weirs. Secular rainfall changes produced periods of high rainfall and large floods (flood‐dominated regimes) between 1857 and 1900 and 1947 and the present, and an intervening period (1901–46) of low rainfall and small floods (drought‐dominated regime). Upstream impoundment and flow regulation significantly reduced flood magnitudes for most return periods during both types of flood regimes. The probability distribution of mean daily flows was also changed significantly by flow regulation such that during the drought‐dominated regime, the high and low frequency flows were reduced substantially but the moderate frequency flows were increased due to dam releases; the change from a regulated drought‐dominated regime to a regulated flood‐ dominated regime resulted in a substantial increase in discharge for most durations; and increased water diversions to Wollongong during the current flood‐dominated regime produced a marked downward shift in the whole flow duration curve. Nepean Dam reduced downstream suspended sediment yields by two orders of magnitude because it traps in excess of 99 per cent of the inflowing suspended sediment load. Streamflow releases are urgently required from the two diversion weirs to improve downstream water quality and to ensure the viability of the resident ‘potentially threatened’ eastern Macquarie perch (Macquaria nov. sp.). 相似文献
18.
Groundwater resource is vital to the sustainable development of socio-economics in arid and semi-arid regions of Northwest China. An estimation of the groundwater resources variation in Zhangye Basin was made during 1985–2013 based on long-term groundwater observation data and geostatistical method. The results show that from 1985 to 2013, groundwater storage exhibited tremendous dissimilarity on temporal and spatial scale for the whole Zhangye Basin, especially before and after implementation of the water diversion policy. Trend of groundwater storage varied from quick to slow decline or increase. The accumulative groundwater storage decreased nearly 47.52×10~8 m~3, and annual average depletion rate reached 1.64×10~8 m~3/a. Among which, the accumulative groundwater storage of the river and well water mixed irrigation district decreased by 37.48×10~8 m~3, accounting for about 78.87% of the total groundwater depletion of the Zhangye Basin. Accumulative depletion of groundwater storage varied in respective irrigation districts. Though groundwater resources depletion rate slowed down from 2005, the overall storage in the whole basin and respective districts during 1985–2013 was still in a severe deficit such that, the groundwater resource was in a rather negative balance, which could threaten the local aquifer. This is the joint effect of climate change and human activities, however human activities, such as water diversion policy and groundwater exploitation, became increasingly intense. Our research results could provide a reasonable estimation for the groundwater balance in Zhangye Basin, providing a scientific basis for water resources unified planning and, this method can provide a relatively reliable way of estimation for large scale groundwater resources. 相似文献
19.
额济纳盆地地下水盐化特征及机理分析 总被引：17，自引：10，他引：7
运用水文地球化学方法,分析额济纳盆地不同含水层地下水盐化特征及其机理。结果表明:额济纳盆地地下水受水文地质条件的制约,潜水的盐化自沿河主要补给区到蒸发排泄区具有明显的分带性,由河流主要补给区向北和向东西两侧,至居延海,进素土海子和古日乃湖中心洼地地下水,地下水由淡水,逐渐过渡为微咸水、中度咸水及极度咸水、盐水;承压水属于微咸水。依据地下水中各离子含量的比值特征的分析结果,控制本区地下水盐化的主要因素为硅酸盐矿物溶解和蒸发沉积作用,硅酸盐矿物溶解主要发生在沿河的地下水补给区;蒸发沉积作用主要发生在地下水径流-排泄区。深层地下水埋藏较深,蒸发的作用大大减弱,因而含盐量少,水质较好。 相似文献
20.
在分析土力类泥石流的产流特征和规律，尤其是土源与水源关系的基础上，将水文学上常用的等流时线法的基本原理应用于小流域土力类粘性泥石流的汇流计算。在具体的计算中，以滇东北蒋家沟的一支沟－大凹子沟1994－06－16的泥石流为例进行泥石流汇流流量过程的试算。计算的结果应用观测的一些数值及现象和弯道超高的最大流量计算值检验，结果表明此计算大体可以定量地反映该流域流量的过程。通过此汇流计算还可以了解阵性泥石流与连续泥石流的产生关系和机理，也可以了解降雨时段与产流时段及汇流过程时段的差别。该研究的结果也存在主客观的局限性，这一局限性反映了进一步探讨流域的产流量规律、流域等流时区划分的规律、大流域汇流计算和泥石流的波坦化规律的必然性。 相似文献