塔里木河下游生态输水及植被恢复遥感监测评价

在干旱区内陆河流域,由于水资源过度开发利用,生态环境退化已成为普遍现象.向断流的河道和生态退化区域实施生态输水,是河流生态系统恢复的基本行为和必然过程.基于向塔里木河下游7次生态输水过程中地表水、地下水、植被恢复等系统监测,并运用卫星遥感技术,对生态输水后植被恢复响应特征指标NDVI(植被指数),进行了系统研究分析,并提出植被相对恢复度的评价方法.     

塔里木河下游输水优化配置模型研究

在调查塔里木河下游各子区生态用水需求的基础上,采用带约束条件的非线性优化理论建立了塔里木河下游各子区优化分配水量模型。采用Kuhn-Tucker条件,对模型进行求解,合理分配了各子区的输水水量。计算结果表明,通过向塔里木河下游河道输水3.4亿m3,可改善下游生态面积达1 490 km2。所建模型为将来的应急输水及水资源的合理配置提供了技术支持。     

塔里木河流域适应气候变化和人类活动的应对措施

自2001年开始实施塔里木河流域近期综合治理工程,提出了以强化流域水资源统一管理和调度为核心,以源流区节水改造和干流河道治理为重点进行综合治理,积极稳妥地进行经济结构调整,实施退耕封育保护,有效保护好现有天然林草植被.通过向塔里木河下游生态输水,干涸近30a的台特玛湖于2001年11月16日开始有水,使塔里木河下游绿色走廊得到初步复苏等,流域生态环境得到极大的恢复.然而,自2007年以来,塔里木河向下游输水已大为减少,仅能输水到中游,特别是2009年水文干旱,塔里木河干流断流达1 100km多,使下游绿色走廊再度陷入生态危机.为此,需要重新审视塔里木河流域的综合治理,从加强源流治理开始,来巩固干流治理成果.认真总结10a来治理经验与教训,针对人类活动和气候变化对源流与干流造成的影响程度,积极采取应对措施.     

塔里木河下游生态输水后地下水变化规律研究

为准确反映塔里木河下游生态输水工程后地下水的动态变化,实现为本地区开展大规模的生态恢复和重建工作提供科学依据,在塔里木河下游沿321km河道上布设了9个监测断面和39口监测井,采用电导法定期监测地下水位近3年。结果显示:输水后地下水位在河道纵向、横向上有各自的变化规律,说明生态输水的效益是逐步显现的。因此,对本地区生态输水的综合评价应该放在几年以后再开展。同时,通过对生态输水后地下水位变化的分析,提出了调整输水规模和方式的建议。     

塔里木河下游输水过程的分析与模拟

塔里木河下游已经干涸断流多年,其"绿色走廊"濒临消失.自2000年5月至2001年11月,先后3次实施向塔里木河下游输水,使下游的水文状况得到了改善,生态得到了一定程度恢复.根据塔里木河下游3次应急输水的有关资料,在输水过程的分析与模拟方面进行了研究,重点是第2次输水过程的分析模拟.从流量沿程损失率及水头前进速度出发,模拟了历次输水的流量沿程分布、输水距离、输水历时及输水水量,为评价输水的水文效应及选择适当的输水方案提供了初步依据.     

塔里木河下游生态输水后植被景观格局动态变化研究

2000-2005年, 塔里木河流域管理局先后7次向塔里木河下游断流区进行了生态输水, 输水河道两岸的植被得到了一定的恢复. 以2000-2005的中巴资源卫星CCD影像为主要数据源, 获得了6 a的植被/非植被二值图, 并计算各年的景观格局指数, 分析了6 a植被景观格局的变化. 结果表明: 植被景观动态度在第四时段(2003-2004年)最大, 为47.83%; 在第三时段(2002-2003年)最小, 为-1.39%; 2000-2005年植被景观的动态变化呈正向趋势. 2000-2005年, 植被景观斑块个数与景观形状指数增加, 蔓延度指数下降了36.9, 斑块结合度指数均高于99, 表明研究区的植被景观破碎化程度、分离程度增加, 而景观类型联通性较高. 植被斑块面积均处于增加趋势且远离河道植被恢复率越小, 但植被景观的比重仍小于50%, 说明非植被类型是研究区的基质类型, 组成了景观的最大斑块. 针对缓冲区Zone 1, 植被景观的平均分维数处于减小趋势且2005年的斑块个数最小, 斑块结合度指数处于增加趋势, 表明近河道区域植被较为稳定, 受生态输水的干扰度较小, 植被景观斑块之间越来越聚集. 6 a间Zone 1的植被最大斑块指数均大于10%, 远高于其它5个缓冲带, 表明离河道越近植被景观的优势度最大.     

基于CBERS数据的塔里木洞下游植被遥感监测研究

文章以生态应急输水为背景,利用遥感、GIS等空间信息技术,分别选取3个时相的CE—BELLS-1CCD遥感影像作为研究数据,对塔里木河下游生态响应进行遥感监测。结果表明：遥感技术可以为塔里木河应急输水对塔里木河流域生态环境带来的影响给出定量的科学的评价指标。     

塔里木河流域2006年“四源一干”河川径流及输水运行分析

2006年塔里木河四条源流出山口天然径流量268.9×108m3, 比正常年份偏多17.4%, 属偏丰水年. 其中, 阿拉尔站以上的三条源流(阿克苏河、叶尔羌河、和田河)出山口天然径流量为228.6×108m3, 比正常年份偏多18.0%;开都河-孔雀河为40.33×108m3, 比正常年份偏多20.4%, 属偏丰水年. 四条源流入塔里木河总水量为50.26×108m3, 占出山口天然径流总量的18.7%. 其中: 阿拉尔站以上三条源流入塔里木河水量为47.58×108m3, 占三条源流出山口天然径流总量的20.8%. 2006年塔里木河干流上游段耗水量33.55×108m3, 占阿拉尔站年径流量的58.8%, 是塔里木河干流最大的耗水区段;中游段耗水量16.56×108m3, 占阿拉尔站年径流量的29.0%, 比多年平均耗水量22.51×108m3减少5.95×108m3;下游段耗水量6.97.16×108m3. 上游耗水量在增加, 中游耗水量在减少, 下游耗水量接近多年平均值. 2006年第8次向干流下游输送生态水2.33×108m3, 其中由博斯腾湖下泄0.26×108m3, 由塔里木河自身来水下泄2.07×108m3. 此次输水由前7次的应急输水转变为功能性输水, 由以往输往塔里木河尾闾台特玛湖, 转变为以扩大下游生态灌溉面积为目的, 尝试以激活天然种子库, 高效利用水资源, 进一步恢复塔里木河下游生态植被范围. 2000-2006年连续共8次生态输水, 已累计由大西海子水库向塔里木河下游输送生态水22.75×108m3, 生态、经济、社会效益日益显著.     

塔里木河下游河道疏浚段水文地质和工程地质特征研究

塔里木河下游河道长期断流,生态环境恶化,必须实施河道疏浚工程,从根本上改善塔里木河下游的生态环境.掌握塔里木河下游河道的水文地质和工程地质特征是实施河道疏浚工程的关键,是沿线生态闸堰设置及两岸提防工程修建的基础.通过区域地质特性、水文地质条件、工程地质特征几个方面的研究,得出河道疏浚段的地层岩性、地下水类型、地下水化学类型等特征,为河道疏浚工程奠定了基础.     

生态输水条件下塔里木河下游断面尺度地下水流数值模拟

由于中国西北地区地表水资源有限,地下水则成为重要的备用水资源,而地表水和地下水转化过程及其耦合模拟是水资源开发利用和科学评价的基础,因此,为了准确反映塔里木河下游间歇性生态输水后地下水的动态变化,以塔里木河下游英苏断面为例,基于Boussinesq方程建立了改进的地下水动力学(GH-D2)模型,模拟了塔里木河下游绿色走廊典型断面地下水对全时段(2000-2015年)间歇性生态输水的响应过程。结果表明,尽管Boussinesq方程的GH解能较好地模拟地下水位的瞬态变化,但模拟地下水位多年变化的结果并不理想,而改进的GH-D2模型考虑了间歇性生态输水对地下水位变化的滞后效应,对长时间尺度地下水位变化的模拟具有较好的效果。与GH和GH-D1模型相比,GH-D2模型模拟的地下水位值更接近于观测值,这将对塔里木河下游实施科学合理的生态输水计划以及生态恢复和重建策略提供关键的技术支撑。     

Desert riparian vegetation and groundwater in the lower reaches of the Tarim River basin

The Green Corridor in the lower reaches of Tarim River in northwestern China has an extreme hot and dry climate. Vegetation here, consisting of arbor, shrub and grass, relies on groundwater exceedingly. However, the increasing anthropogenic activities of large-scale agricultural reclamation and unreasonable water utilization in the upper and middle reaches caused the 321-km riverway in the lower reaches to dry up completely in 1972 and resulted in the sharp decline of groundwater, followed by the ruin of desert riparian vegetation on a large scale. The Green Corridor is on the verge of shrinking. Water has a key role in maintaining ecological balance and socioeconomic development. This paper, focused on the relationship between vegetation and groundwater, discusses (1) the change of groundwater table caused by the ecological water delivery carried out in the lower reaches of Tarim River; (2) the appropriate groundwater depth meeting the vegetation’s survival; (3) the minimum ecological flux and ecological water requirement for the growth of natural vegetation. It was shown that (1) based on the analysis of the monitoring data from the groundwater level of ten times water delivery, such an extensive artificial watering takes positive effect on raising the groundwater level along the two sides of the river; (2) a groundwater table depth of 2–4 m is probably the appropriate ecological water table level for the lower reaches of the Tarim River, and 6 m is the threshold for the local vegetation; (3) at the lower Tarim River, 1.157 × 10⁸ m³ of water flow is needed for itself. The longer the duration of water releases, the greater would be the groundwater rise and the larger the range of vegetation influenced. It was found that the duration and volume of water delivery was closely related to restoration of vegetation in the lower reaches of the Tarim River. The goal of this paper is to offer scientific evidences for water delivery in the rigorous areas to maintain an ecological balance.     

The influence of water conveyances on restoration of vegetation to the lower reaches of Tarim River

Because of long-term stream-flow cut off in the lower reaches of Tarim River, environmental degradation has become the most severe and widespread environmental problem in Tarim River basin. Nine ecological water conveyances to the lower reaches of Tarim River made ecological environment change a lot. 3S technology was used to monitor dynamic change of ecology. However, remote sensing area index cannot analyze ecological restoration degree of Tarim River precisely because the time of each water conveyance is short, the change of vegetation area is not obvious, and there exists visual interpretation error. In this paper, remote monitoring datum of high temporal resolution and high spatial resolution were used to research the relationships between normalized difference vegetation index (NDVI) and the groundwater depth, between NDVI and the surface vegetation coverage, and between the groundwater depth and the surface vegetation coverage. The growth and restoration of the vegetation in different periods were evaluated by investigative analysis of the change trend of NDVI. The conception of relative restoration degree was proposed and the response of vegetation restoration to the water conveyance was evaluated. The evaluation result suggests that: first, the response of vegetation to the water conveyance concentrates within 1,000 m of both riversides, and the range of influence becomes smaller along the lower reaches of Tarim River. Second, influenced by the groundwater recharge, the vegetation coverage shows decreasing trend with the increase of off-river distance. Third, the vegetation coverage shows decreasing trend along the watercourse influenced by the water consumption. Finally, in spatial, original scattered meadow of low coverage transforms to high coverage gradually in research region. Vegetation response to the water conveyance expands to both sides with the watercourse being the axis, and expanding scale increases continuously.     

Response of riparian vegetation to water-table changes in the lower reaches of Tarim River, Xinjiang Uygur, China

The lower reaches of Tarim River in the Xinjiang Uygur region of western China had been dried out for more than 30 years before water began to be diverted from Konqi (Peacock) River via a 927-km-long channel in year 2000, aimed at improving the riparian ecological systems. Since then, eight intermittent water deliveries have been carried out. To evaluate the response of riparian vegetation to these operations, the groundwater regime and vegetation changes have been monitored along the 350-km-long stem of the river using a network of 40 dug wells at nine transects across the river and 30 vegetation plots at key sites. Results show that the water table rose remarkably, i.e. from a depth of 9.87 m before the water delivery to 3.16 m after the third water delivery. The lateral distance of affected water table extended to 1,050 m from the riverbank after the fourth water delivery. The riparian vegetation has changed in composition, type, distribution, and growing behavior. This shows that the water deliveries have had significant effects on restoration of riparian ecosystems.     

中国西北地区额济纳绿洲植被盖度与黑河流量的滞后效应研究

干旱区植被生长与地下水的关系是生态水文地质学研究的热点之一。西北干旱地区,由于降水稀少,绿洲是当地人类生存和发展的主要依托。近年来,随着黑河流域中游地区用水量的逐年加大,下游来水量减少,使得下游额济纳绿洲的面积不断减小,湖泊干涸,沙漠化严重,生态环境恶化。由于绿洲植被的生长与水有极为密切的关系,因此,研究河流流量与绿洲植被生长之间的定量关系,对改善黑河流域生态环境、协调用水矛盾和合理配置水资源具有重要意义。将遥感数据与黑河径流量数据相结合,在区域尺度上定量研究额济纳绿洲植被生长与河流径流量的关系。结果表明,绿洲植被对黑河径流以及地下水有很强的依赖关系,而且黑河径流对额济纳绿洲的影响存在一年的滞后期,而地下水则通过这种滞后作用将两者联系起来。     

Desert riparian forest colonization in the lower reaches of Tarim River based on remote sensing analysis

The ecological water conveyance project that pipes water from Daxihaizi reservoir to lower reaches of Tarim River has been implemented ten times since 2000. After ecological water conveyance, restoration has taken place for vegetation along the dried-up lower reaches of the Tarim River. The changes of vegetation fluctuated yearly due to ecological water conveyance. In order to reveal the detailed process of vegetation changes, remote sensing images from 1999 to 2010 were all classified individually into vegetated and non-vegetated areas using the soil-adjusted vegetation index threshold method. Then inter-annual changes of vegetation over a period of 12 years were obtained using a post-classification change detection technique. Finally, spatial–temporal changes distribution of vegetation cover and its response to ecological water conveyance were analyzed. The results indicate: (1) vegetation area increased by 8.52 % overall after ecological water conveyance. Vegetation between 2003 and 2004 increased dramatically with 45.87 % while vegetation between 2002 and 2003 decreased dramatically with 17.83 %. (2) Vegetation area gain is greater than vegetation loss during 1999–2000, 2001–2002, 2003–2004 and 2009–2010 periods. Although vegetation restoration is obvious from 1999 to 2010, vegetation loss also existed except for the periods above. It indicates that vegetation restoration fluctuated due to ecological water conveyance. (3) Spatial distribution of vegetation restoration presented “strip” distribution along the river and group shaper in the lower terrain area, while spatial distribution of vegetation loss mainly located in the upper reaches of river and area far away from the river. (4) Vegetation restoration area had a positive relative with total ecological water conveyance volume. The scheme and season of ecological water conveyance had also influenced the vegetation restoration. The vegetation change process monitoring, based on continuous remote sensing data, can provide the spatial–temporal distribution of vegetation cover in a large-scale area and scientific evidences for implementing ecological water conveyance in the lower Tarim River.     

现浇透水性生态混凝土在河道边坡工程中的应用

针对传统护坡工程方法在河道边坡工程生态环境保护和修复方面的缺陷,提出了新型现浇透水性生态混凝土护坡技法,优化设计了该技法组成材料,并对生态混凝土的耐久性、植生能力和净水性能进行了综合分析。通过该技法在泰州周山河河道边坡生态治理工程中的实际应用,认为所提出的现浇透水性生态混凝土护坡技法不仅能充分保证护坡工程的安全性,还可维持和改善周边生态环境与生态系统。     

塔里木河干流河道水均衡模型研究

通过对河道水面蒸发量、渗漏量、漫溢量的分析,建立了以月为单位的塔里木河干流河道水均衡模型.该模型以阿拉尔来水量为输入,输出包括干流主要水文站点的水量、各河段的蒸发量、渗漏量、漫溢量等.利用1981—1995年逐月的水文资料进行了模型参数率定,以1996—2000年的水文资料进行了模型验证,结果表明模型具有较好的适应性.利用该模型分析塔里木河干流水资源转化消耗的规律,得出河道漫溢尤其是中游的漫溢是塔里木河干流主要的水量消耗.考虑堤防建设对模型进行了修正,并利用修正后的水均衡模型分析了堤防建设的影响.     

新疆塔里木河下游物种多样性变化与地下水位的关系

根据塔里木河下游9个断面40眼地下水位观测井和8个植物样地野外采集的数据，运用物种多样性指数对塔里木河下游物种多样性与地下水位变化进行了分析计算。研究表明，塔里木河下游物种多样性与地下水位变化有着密切的关系，地下水位对物种多样性的变化起着主导作用。塔里木河下游浅层地下水位埋深较大，并且表现为由上游段至下游段逐渐加深这样一个明显的递减变化。塔里木河下游物种多样性指数较低，Shannon Weiner指数和Simpon指数分别变化在1.93~0.53之间和0.82~0.35之间；随着由上游段至下游段地下水位埋深的加大，塔里木河下游植物种类减少、群落结构简单、物种多样性指数和丰富度指数呈明显降低的态势。反映了干旱区水分胁迫对生态系统的强烈影响。