引哈济党工程对苏干湖湿地天然植被的影响

根据Processing MODFLOW模型对调水后大苏干湖区面积和湿地地下水位的影响预测结果,初步确立引哈济党工程适宜调水量,并在各调水方案的基础上,以干旱区天然植被与地下水的定量关系为依据,分析预测地下水位下降对湿地天然植被的影响。结果表明:不同工况引水50 a后,大苏干湖湖泊面积减少均不超过8%;湿地地下水水位0 m~1 m区面积将持续下降,最大减少17 km2;湿地天然植被部分将发生演替,主要由湿生植被向中、旱生植被演变,影响集中在两湖间河道湿地及湿地外围边缘地带。     

荒漠生态系统监测研究指标体系

新疆环境保护科学研究所自1984年接受“荒漠生态系统监测指标体系的观测研究”课题,在乌鲁木齐北部90km处的沙漠边缘建立了“准噶尔沙漠生态系统定位研究站”,自1987年正式开展了“荒漠生态系统定位观测研究”工作,从古尔班通沙漠中部至天山博格达峰中山带选定了沙漠、沙漠边缘、山前洪冲积扇、前山和中山带五个观测场,沙漠四季进行定位观测,同时,在站内进行多项目的连续观测,现集五年观测研究经验,结合中国科学院及国外研究站的先进经验,建立了荒漠生态系统指标体系。     

乌鲁木齐地区地下水污染现状及其对策

据调查乌鲁木齐流域地表水径流总量为 4.6364亿方/年,地下水天然资源为2.63亿 方/年,合计为7.2664亿方/年。人均水量 621方/年,全国人均水量2700方/年,相 差四倍多,而我国人均水量仅居世界第五 位。 随着国民经济的发展,城市人口的增加,预计到2000年,乌鲁木齐地区人口将增加到150万人。这就意味着人均水量还将逐年减少,供需矛盾日益突出,保持现在用水水平是不可能的,国民经济发展和保护水资源要同步考虑,采取有效的防治措施和对策。 乌鲁木齐近二十年来,由于地下水开采量大于天然补给量,使乌鲁木齐河谷潜水位大幅度下降。据计算每年动用地下水储量910万方。自1966年以来地下水位下降了10米左右,年平均下降0.54米。三甬碑一水厂3号井,1966年地下水位7.57米,至1983年地下水位下降到17.29米,矿化度从0.28克/升,增加到0.5克/升;二宫二水厂43号     

EV生化、生态组合净化技术处理农村生活污水的应用

采用EV生化、生态组合净化技术处理农村生活污水,对工艺的运行效果、污染物的去除途径及温度对污染物去除率的影响进行了研究分析.一年的观测结果表明,该工艺结合了生物技术和生态工程的优点,能有效去除生活污水中的有机物、氮、磷和粪大肠菌群,且处理效果稳定.温度对有机物、总磷的去除效率影响较小,对总氮、氨氮去除效率影响较大,在冬...     

湖北臭氧分布特征及其管控措施

采用地面站点观测、卫星观测以及UWCM 0-D箱子模型模拟的方法研究湖北2013—2015年臭氧时空分布特征,并探讨其管控措施。从地面站点观测看出,时间分布上,这3年臭氧年平均浓度经历先下降后上升的过程,总体呈上升趋势,而二氧化氮年平均浓度则呈现持续下降的趋势;空间分布上,湖北各区域臭氧浓度分布不均匀,呈现东高西低的递减分布趋势。从卫星观测数据看出,2015年湖北的臭氧柱浓度高于2013、2014年同期。从空间分布来看,臭氧的柱浓度是从东北到西南、从省外到省内逐渐递减,因此推测,除了本地生成,湖北的臭氧有一部分是来源于省外传输。最大臭氧生成量法显示,烯烃(乙烯和丙烯)对湖北夏天臭氧生成量的贡献远大于其他挥发性有机化合物。箱子模型模拟的结果显示,湖北应该通过控制挥发性有机化合物的排放来降低臭氧生成速率,控制氮氧化物反而使臭氧生成速率提高。     

中国高分辨率近地面NO2浓度反演

通过分析2010年全国333个县级以上城市卫星遥感的NO2对流层年均柱浓度与地面实际观测浓度之间的相关性,发现两者具有一定的线性相关性(r=0.54,n=333),并建立了NO2"遥感柱浓度"与"地面观测浓度"之间的关联方程,通过该方程反演了中国0.125°分辨率近地面NO2污染分布特征。结果表明,全国近地面NO2浓度超过《环境空气质量标准》(GB 3095—2012)要求的年均浓度二级标准(0.04 mg/m3)的区域约为5.95万平方千米,超标地区主要集中在华北平原、长三角地区、四川盆地和珠三角地区,这些地区NO2污染水平远高于333个城市的年平均值(0.028 mg/m3)。NO2污染极不平衡,以大中型城市为中心的区域污染特征显著。NO2人口加权浓度分析结果表明,NO2人口加权浓度高值区主要集中在能源消费量大、机动车保有量大及人口密集的地区,全国约5.7%的人口暴露在NO2超标区域。     

基于底栖动物的水质生物学评价——以江苏骆马湖为例

基于2018年1—11月骆马湖水质和底栖动物逐月监测数据,利用Goodnight指数(GBI)、生物学污染指数(BPI)、Shannon-Wiener指数(H′)等生物学指数对水质现状进行了评价。结果表明,骆马湖ρ(总氮)年均值为2.31 mg/L,ρ(总氮)和ρ(溶解氧)呈先下降后上升趋势;ρ(总磷)年均值为0.05 mg/L,先上升于8月达到峰值(0.15 mg/L)后下降;高锰酸盐指数呈先上升后下降趋势;ρ(氟离子)呈逐渐下降趋势,水温和电导率存在明显季节变化,pH值呈逐渐升高趋势。共鉴定出底栖动物27种,其中软体动物5种,环节动物7种,节肢动物15种。铜锈环棱螺(Bellamya aeruginosa)、红裸须摇蚊(Propsilocerus akamusi)、纹沼螺(Parafossarulus striatulus)、苏氏尾鳃蚓(Branchiura sowerbyi)、霍甫水丝蚓(Limnodrilus hoffmeisteri)、多巴小摇蚊(Microchironomus tabarui)和中国长足摇蚊(Tanypus chinensis)是现阶段优势种。全湖底栖动物年均密度为174.5个/m 2,年均生物量为24.93 g/m 2,表现出明显的时空差异。水质评价结果表明,骆马湖水环境处于中污染状态。结合近年来研究结果,骆马湖底质荒漠化现象趋于好转,但富营养化趋势正在加深。     

2001—2018年浙江省酸雨变化特征及影响因素分析

利用2001—2018年浙江省32个城市酸雨观测资料,结合数理统计和GIS空间插值,分析了全省降水酸度变化、化学组分特征及其影响因素。研究结果表明,以2009年为拐点,浙江省酸雨污染呈先加重后减轻的趋势,降水酸度和酸雨率均得到显著改善。2009年后,轻酸雨城市的比例不断上升。至2018年,全省大部分城市均处于轻酸雨区,并有部分非酸雨城市出现。降水中的硫酸根离子浓度呈显著下降趋势,硝酸根离子浓度呈波动变化,但变化不显著。硫酸根离子与硝酸根离子的当量浓度比值呈显著下降趋势,由2002年的3.48降至2018年的1.35,酸雨类型由硫酸主导型向复合型转变。二氧化氮、硝酸根离子和可吸入颗粒物是影响降水pH的主要因素,氮氧化物对浙江省降水酸度的影响不断增大。因此,在加强区域硫氮协同控制的同时,着力加强氮氧化物深度减排是进一步改善浙江省酸雨状况的关键。     

2010年春季沙尘天气对北京市空气质量的影响及其天气类型分析

利用2010年3-5月北京市市区以及北京西北部、西部和东部3个不同方位边界的空气质量自动监测站监测数据,结合气象资料和激光雷达观测数据,分析了春季外来沙尘对北京市空气质量的影响。研究结果表明:2010年春季北京市出现15次外来沙尘天气,外来沙尘输送对北京市空气质量的影响天数为21 d,直接造成15 d空气质量超标,最严重的一次API指数达到最大值500。沙尘的天气形势特征以及输送路径的不同,对北京市空气质量的影响有明显差异。当低压中心过境时,沙尘天气影响最重,颗粒物浓度显著上升,气态污染物迅速下降,沙尘呈现自西北向东南输送的特征;低压底部过境与低压中心过境类似,但是沙尘强度略弱;除此之外,沙尘回流也可以直接造成北京市空气质量超标,颗粒物浓度和气态污染物浓度均表现出上升的变化趋势。     

我国风速反弹特征及其对湖泊富营养化的潜在影响

在2010年前后全球范围内出现“大气静止”恢复、近地面风速反弹上升的现象。然而这一风速反弹现象对我国湖泊的影响尚不清楚。通过对全国745个气象监测站观测数据进行空间插值提取湖泊近地面风速时间序列,使用分段线性回归分析了我国面积＞1km²的湖泊和87个重点监测湖泊风速反弹现象的特征。结果显示,全国面积＞1km²的湖泊有71.59%出现风速反弹现象,但是东部沿海地区和新疆东部地区湖泊未出现风速反弹,重点监测的富营养化湖泊只有43.08%出现风速反弹。同时,出现风速反弹的湖泊风速转折点年份分散。预计风速反弹现象在未来短期内可能有利于我国湖泊富营养化治理,但在未来长期内气候变化将出现风速下降现象,可能对湖泊富营养化治理造成不利影响。     

Groundwater Modeling in Agricultural Watershed under Different Recharge and Discharge Scenarios for Quaternary Aquifer Eastern Nile Delta,Egypt

Different scenarios of recharge and discharge were assessed for sustainable management of groundwater in Quaternary aquifer east of Nile Delta. MODFLOW was utilized to investigate the effect of land use change and damming construction in the upstream of the Nile River on the current and short-term groundwater management strategies. The interpretive transient simulation was performed between 2004 and 2016 after steady-state calibration in 2004, and transient state from 2004 to 2013 with different irrigation recharges associated with land use change in this period. Sensitivity analysis was performed for hydraulic conductivities, recharge, and conductance parameters. The predictive transient simulation was run till 2023 under three scenarios of increasing pumping rates by 15, 30, and 50% for agriculture expansion and specified head reduction of Port Said Canal by 0.2, 0.4, and 0.6 m associated with the reduction of Nile water levels after Grand Ethiopian Residence Dam, GERD operation in 2017. Results from the in- and out-flow budgets showed that groundwater aquifer is stable at the current rate of pumping till 2023. Groundwater heads decreased by 0.2 and 0.42 m in the southern section, and a slight increase in the northern part was noticed for the first and second scenarios, respectively. When additional pumping stress is applied (50% increase), groundwater head dropped by 0.66 m, and the storage is no longer able to maintain the aquifer capacity after 2020 (worst-case scenario).     

Appraisal of the groundwater balance components from multi-remote sensing datasets in a semi-arid region

Semi-arid regions across the globe are fronting water crises, signaling a challenge to ensure future water security. Given the high inter-seasonal rainfall variability and unrestrained groundwater extraction, the precise quantification of groundwater flow components in an aquifer system is a priority. To address this challenge, we used high-resolution remote sensing (RS) data (Landsat and IRS) and GIS modeling (SEBAL, ArcCN) to spatially quantify major groundwater balance (GWB) components, viz., evapotranspiration (ET), rainfall recharge (R), surface runoff (Q), groundwater extraction (PG), irrigation return flow (IRF), and ultimately changes in groundwater storage (ΔS) in a small semi-arid crystalline representative watershed. Results show that a total of ~?230 mm of groundwater is extracted during 2008–2009, creating a negative impact on the groundwater resource, which is further enhanced by limited recharge and high ET. A decrease of approximately 65 mm in groundwater storage is observed in a single hydrological year, and given a very low specific yield, this decrease will introduce large water level decline. The study establishes that declining groundwater level in the watershed is a direct result of over-extraction, and owing to this scenario, efficient irrigation and land use policies are suggested as potential approaches to minimize extraction specifically in the dry season. Our methodology provides a systematic assessment of vital GWB components at a high spatial resolution and an insight on various sustainable mitigation methods. This methodology is useful in the planning and management of groundwater resources, particularly in water-stressed areas.     

Environmental impact assessment and seasonal variation study of the groundwater in the vicinity of River Adyar, Chennai, India

Hydrochemical investigations of the groundwater and the seasonal effect on the chemical budget of ions along the course of the polluted river Adyar were carried out. From the geochemical results, it has been found that the seasonal effect does not change the order of abundance of both cations and anions, but it does change the concentration of various ions present in the groundwater. Among the chemical budget of ions, sodium and chloride were found to be the most predominant ions. The nitrate concentration in the groundwater ranges from 4.21 to 45.93 mg/l in pre-monsoon and in post-monsoon it ranges from 1.02 to 75.91 mg/l. The nitrate concentrations in the post-monsoon are high in some places especially in the upper stretch of the river. The intense agricultural activities near the upper stretch of the river may be an important factor for the higher concentration of nitrates in these aquifers. In order to determine the geochemical nature of water, the data was interpreted using the piper diagram wherein the results show the predominance of NaCl and CaMgCl types. Equiline diagrams, 1:1, were applied to evaluate the affinity ion relationship between various ions present in these waters. The quality of the groundwater was assessed with regard to its suitability to drinking and irrigation. A comparison of the groundwater quality in relation to drinking water quality standards shows that most of the water samples are not suitable for drinking, especially in post-monsoon period. US Salinity Laboratory's, Wilcox's diagrams, Kellys ratio and magnesium ratio were used for evaluating the water quality for irrigation which suggest that the majority of the groundwater samples are not good for irrigation in post-monsoon compared to that in pre-monsoon. Moreover the source of the ions in the water was examined and classified accordingly using Gibb's diagram. The analytical results reveals that the TDS values of the pre-monsoon samples were found to be lower than the post-monsoon reflecting that leaching predominates over that of the dilution factor.     

Computation of groundwater resources and recharge in Chithar River Basin, South India

Groundwater recharge and available groundwater resources in Chithar River basin, Tamil Nadu, India spread over an area of 1,722 km² have been estimated by considering various hydrological, geological, and hydrogeological parameters, such as rainfall infiltration, drainage, geomorphic units, land use, rock types, depth of weathered and fractured zones, nature of soil, water level fluctuation, saturated thickness of aquifer, and groundwater abstraction. The digital ground elevation models indicate that the regional slope of the basin is towards east. The Proterozoic (Post-Archaean) basement of the study area consists of quartzite, calc-granulite, crystalline limestone, charnockite, and biotite gneiss with or without garnet. Three major soil types were identified namely, black cotton, deep red, and red sandy soils. The rainfall intensity gradually decreases from west to east. Groundwater occurs under water table conditions in the weathered zone and fluctuates between 0 and 25 m. The water table gains maximum during January after northeast monsoon and attains low during October. Groundwater abstraction for domestic/stock and irrigational needs in Chithar River basin has been estimated as 148.84 MCM (million m³). Groundwater recharge due to monsoon rainfall infiltration has been estimated as 170.05 MCM based on the water level rise during monsoon period. It is also estimated as 173.9 MCM using rainfall infiltration factor. An amount of 53.8 MCM of water is contributed to groundwater from surface water bodies. Recharge of groundwater due to return flow from irrigation has been computed as 147.6 MCM. The static groundwater reserve in Chithar River basin is estimated as 466.66 MCM and the dynamic reserve is about 187.7 MCM. In the present scenario, the aquifer is under safe condition for extraction of groundwater for domestic and irrigation purposes. If the existing water bodies are maintained properly, the extraction rate can be increased in future about 10 % to 15 %.     

Modeling interactions between saturated and un-saturated zones by Hydrus-1D in semi-arid regions (plain of Kairouan,Central Tunisia)

In semi-arid areas like the Kairouan region, salinization has become an increasing concern because of the constant irrigation with saline water and over use of groundwater resources, soils, and aquifers. In this study, a methodology has been developed to evaluate groundwater contamination risk based on the unsaturated zone hydraulic properties. Two soil profiles with different ranges of salinity, one located in the north of the plain and another one in the south of plain (each 30 m deep) and both characterized by direct recharge of the aquifer, were chosen. Simulations were conducted with Hydrus-1D code using measured precipitation data for the period 1998–2003 and calculated evapotranspiration for both chosen profiles. Four combinations of initial conditions of water content and salt concentration were used for the simulation process in order to find the best match between simulated and measured values. The success of the calibration of Hydrus-1D allowed the investigation of some scenarios in order to assess the contamination risk under different natural conditions. The aquifer risk contamination is related to the natural conditions where it increased while facing climate change and temperature increase and decreased in the presence of a clay layer. Hydrus-1D was a useful tool to predict the groundwater level and quality in the case of a direct recharge and in the absence of any information related to the soil layers except for the texture.     

Does irrigation with reclaimed water significantly pollute shallow aquifer with nitrate and salinity? An assay in a perurban area in North Tunisia

In Tunisia, reclaimed water is increasingly used for irrigation in order to mitigate water shortage. However, few studies have addressed the effect of such practice on the environment. Thus, we attempted in this paper to assess the impact of irrigation with reclaimed water on the nitrate content and salinity in the Nabeul shallow aquifer on the basis of satellite images and data from 53 sampled wells. Ordinary and indicator kriging were used to map the spatial variability of these groundwater chemical parameters and to locate the areas where water is suitable for drinking and irrigation. The results of this study have shown that reclaimed water is not an influential factor on groundwater contamination by nitrate and salinity. Cropping density is the main factor contributing to nitrate groundwater pollution, whereas salinity pollution is affected by a conjunction of factors such as seawater interaction and lithology. The predictive maps show that nitrate content in the groundwater ranges from 9.2 to 206 mg/L while the electric conductivity ranges from 2.2 to 8.5 dS/m. The high-nitrate concentration areas underlie sites with high annual crop density, whereas salinity decreases gradually moving away from the coastline. The probability maps reveal that almost the entire study area is unsuitable for drinking with regard to nitrate and salinity levels. Appropriate measures, such as the elaboration of codes of good agricultural practices and action programs, should be undertaken in order to prevent and/or remediate the contamination of the Nabeul shallow aquifer.     

Effect of the ecological water conveyance project on environment in the Lower Tarim River, Xinjiang, China

The dynamic response of groundwater level is examined in traverse and lengthways directions. Take the Yinsu section for an example, we have simulated groundwater levels before and after water-conveyance every time and calculated the incidence of groundwater on the both sides of the river. It is noted that the effect keeps growing with the water-delivery times increasing, from 570 m after the first times to 3,334 m after the eighth times. In addition, this paper involves the temporal response of the natural vegetation to water conveyance, vegetation coverage, planted-species number, dominant position and species diversity from 2002 to 2006. The findings indicate that the positive influence of ecological water conveyance project (EWCP) on the ecosystem in the Lower Tarim River is a long-term process. In this paper, we try to calculate water required for recovery of damaged ecosystem by using data available. This project is likely the base of research on water demand and the reference of measures for research on ecological water conveyance effect.     

Effect of high sulfate concentration on the corrosivity: a case study from groundwater in Harran Plain, Turkey

Corrosion, which tends to increase the concentrations of certain metals in tap water, is one of the most important water quality problems as it can affect public health and public acceptance of water supply and the cost of providing safe water. In this context, this study aimed at investigating the scale formation tendency or corrosivity of groundwater in the semi-arid Harran Plain. The degree of scale formation tendency/corrosivity of water was determined considering pHs, Langelier Index, and Ryznar Index of groundwater samples. Except for well no.4, which is close to a local hot spring, all the wells had corrosive characteristics. The amount of CO₂ from the soil zone respiration and high sulfate concentration in the wells are important factors affecting corrosiveness. Results showed that precipitation, excessive irrigation, and change in groundwater level caused seasonal variation in corrosive characteristics.     

A hydrochemical elucidation of the groundwater composition under domestic and irrigated land in Jaipur City

The study area Jaipur, the capital of Rajasthan, is one of the famous metropolises in India. In order to know the suitability of groundwater for domestic and irrigation purposes in Jaipur City, groundwater samples were composed of 15 stations during post-monsoon time of the year 2007–2008 (Nov 2007 to Feb 2008) and were analyzed for physicochemical characters. The physicochemical parameters of groundwater participate a significant role in classifying and assessing water quality. A preliminary characterization, carried out using the piper diagram, shows the different hydrochemistry of the sampled groundwater. This diagram shows that most of the groundwater samples fall in the field of calcium-magnesium-chloride-sulfate type (such water has permanent hardness) of water. Data are plotted on the US Salinity Laboratory diagram, which illustrates that most of the groundwater samples fall in the field of C2S1 and C3S1, which can be used for irrigation on almost all type of soil with little danger of exchangeable sodium. Based on the analytical results, chemical indices like %Na, SAR, and RSC were calculated which show that most of the samples are good for irrigation.     

Impact of urbanization on the groundwater regime in a fast growing city in central India

This paper describes the impact of urbanization on the groundwater regime in a fast growing city, Solapur, in central India, giving special emphasis on the management of the present and ultimate demand of water in 2,020 AD. The objective is to apprise the city planners and administrators of the effects of urbanization on the groundwater regime in a fast growing medium-sized city in a developing country where the infrastructure developments are not in conformity with the rapid growth in population. Solapur city with an area of 178.57 km2 receives a recharge of about 24 million m3 of groundwater from various sources annually. Reduction in recharge, as conventionally assumed due to the impact of urbanization, could not, however, be well established. Instead, there was a rise in recharge as water use in the city grew from time to time and more and more water was supplied to satisfy the human needs. Compared to mid-1970s, groundwater levels have increased within the main city area due to increased recharge and decreased groundwater abstraction. However, outside the main city area, there is a general decline in groundwater levels due to increased groundwater utilization for irrigation purposes. Groundwater quality deterioration has been highly localized. Water quality has deteriorated during the last 10 years, especially in dugwells, mainly due to misuse and disuse of these structures and poor circulation of groundwater. However, in case of borewells, comparison of the present water quality with that in mid-1970s and early 1980s does not show any perceptible change. Deeper groundwater tapped by borewells can still be used for drinking purposes with caution.