黑河流域大气降水稳定同位素变化及模拟

利用2002～2004年黑河流域6个采样点上的301个降水数据,对黑河流域大气降水中δD和δ18O的变化进行了分析.结果表明,流域降水δ18O和δD的变化范围分别为6.5‰～-33.4‰和59‰～-254‰,这主要是由于降水水汽来源不同和气象条件特别是气温和降水量的较大变化使得降水形成的凝结机制发生变化引起;降水中同位...     

吉林省主要河流指定标准功能可达性分析

根据吉林省地方标准规定的河流水域功能类别和1995年水质监测结果,采用水质单项标准指数法,对吉林省主要河流34个国控和省控监测断面的单项指标、全指标、有机污染型指标和重金属污染型指标进行了功能评价。结果表明,仅有6个监测断面满足指定的标准功能要求,符合率仅为17.6％,主要超标污染物是COD_Mn和挥发酚。以COD为控制指标,根据逆推法的河流水环境容量模式,计算了污水达标排放情况下的污水允许排放量,从而对河流控制断面指定的标准功能进行了可达性分析。结果表明,污水达标排放时,河流流量较大、污径比较小的河流可达到指定标准功能要求;而枯水期流量较小、污径比较大的河流很难达到,应实施重点污染物的排放总量控制制度。     

Spatiotemporal optical properties of dissolved organic matter in a sluice-controlled coastal plain river with both salinity and trophic gradients

Due to the combined effect of sluices and sea tide, the sluice-controlled coastal plain river would be characterized by both trophic state and salinity gradients, affecting the spatiotemporal optical properties of dissolved organic matter (DOM). In this study, we investigated the spatiotemporal variation of water quality parameters and optical properties of DOM in the Haihe River, a representative sluice-controlled coastal plain river in Tianjin, China. A significant salinity gradient and four trophic states were observed in the water body of the Haihe River. Two humic- and one protein-like substances were identified from the DOM by the three-dimensional fluorescence spectra combined with the parallel factor (PARAFAC) analysis. Pearson's correlation analysis and redundancy analysis (RDA) showed that the salinity significantly affected the abundance of chromophoric DOM (CDOM) but did not cause significant changes in the fluorescence optical characteristics. In addition, the effect of Trophic state index (TSI) on the CDOM abundance was greater than that on the fluorescence intensity of fluorescent dissolved organic matter (FDOM). In the water body with both salinity and trophic state gradients, TSI posed a greater influence than salinity on the CDOM abundance. Our results fill the research gap in spatiotemporal DOM characteristics and water quality variation in water bodies with both salinity and trophic state gradients. These results are beneficial for clarifying the joint influence of saline intrusion and sluices on the DOM characteristics and water quality in sluice-controlled coastal plain rivers.     

Boosting large-scale river connectivity restoration by planning for the presence of unrecorded barriers

Conservation decisions are invariably made with incomplete data on species’ distributions, habitats, and threats, but frameworks for allocating conservation investments rarely account for missing data. We examined how explicit consideration of missing data can boost return on investment in ecosystem restoration, focusing on the challenge of restoring aquatic ecosystem connectivity by removing dams and road crossings from rivers. A novel way of integrating the presence of unmapped barriers into a barrier optimization model was developed and applied to the U.S. state of Maine to maximize expected habitat gain for migratory fish. Failing to account for unmapped barriers during prioritization led to nearly 50% lower habitat gain than was anticipated using a conventional barrier optimization approach. Explicitly acknowledging that data are incomplete during project selection, however, boosted expected habitat gains by 20–273% on average, depending on the true number of unmapped barriers. Importantly, these gains occurred without additional data. Simply acknowledging that some barriers were unmapped, regardless of their precise number and location, improved conservation outcomes. Given incomplete data on ecosystems worldwide, our results demonstrate the value of accounting for data shortcomings during project selection.     

淮河流域致洪暴雨特征及预警指标分析

本文通过对1950～2000年的个例分析,总结了淮河流域致洪暴雨的天气学特征和判别指标;根据区域降水量与王家坝站的水位分析,确定了淮河流域致洪暴雨的预警指标.     

长江干线船舶碰撞原因的故障树分析一以武汉海事局辖区水域为例

以2007年武汉海事局辖区船舶碰撞资料为基础,利用故障树分析方法构建该水域船舶碰撞故障树,进行定性、定链分析,得到包括航行疏于戒备、车舵控制失误、疏于了望等14个主要危险因素及各因素的相关事故数。在故障树分析的基础上,构建布尔代数和最小割集,计算各危险旧素的概率重要度,以衡精各危险因素发生概率的变化给碰撞事故发生概率带来的影响;计算临界重要度,从敏感度和概率双重角度衡量每个危险因素的重要度。通过分析发现应急操作不当、违反其他规定、航行疏于戒备、违反分道通航、疲劳驾驶等人为因素是引起该水域船舶碰撞的重要原因。建议船公司重视船员应急培训,提高船员应急处置能力,海事管理机构加大相关法规宣传力度和监管力度。     

釜溪河自贡城区段季节性低氧成因研究

釜溪河为沱江一级支流,在自贡城区段设有国考碳研所断面。收集碳研所断面近10年来水质自动站数据,分析溶解氧(DO)变化特征,采样调查釜溪河自贡城区段水质及河道底泥污染状况,采用相关性分析、数值模拟等,研究分析釜溪河自贡城区段溶解氧分布特征及碳研所断面季节性低氧成因。研究结果表明,碳研所断面的溶解氧质量浓度变化特征呈现春末夏初最低,白天高晚上低的特征。釜溪河碳研所断面河水耗氧类污染物质量浓度较沱江流域内其他断面高,耗氧强度较大,溶解氧质量浓度较沱江流域其他断面偏低;其次,研究河段中釜溪河污水厂以下河段受污水厂低氧水排入和金子凼堰底层低氧水下泄影响,其溶解氧水平整体较污水厂以上河段低;最后,河段底泥有机质含量较高,春夏季气温升高将导致微生物分解活性增强大量消耗溶解氧,同时,闸坝和外来水体排入的水文扰动造成污水厂以下河段水温梯度弱,表层溶解氧易受底层低氧水影响,促使断面形成季节性低氧现象。溶解氧预测模型结果也进一步证实了温度变化和垂向温度梯度弱是碳研所断面溶解氧质量浓度季节性偏低的主要因素。     

引调水河道氮的迁移转化及微生物群落结构特征——以望虞河为例

以引江济太调水工程-望虞河为研究对象,探究引调水河道氮素的迁移转化规律及微生物群落结构特征.于2020年10月、12月以及2021年1月在望虞河沿程布设监测点位并采集水样,分析其水体理化性质、氮的形态分布及含量、微生物群落结构变化特征.结果 表明:①硝酸盐氮是望虞河沿程水体中氮素的主要存在形态,占总氮浓度的75.3％～...     

长江中游荆南三口断流时间演变特征及其影响机制

研究河道断流演变特征对认识区域水文过程及人类活动具有重要作用。论文依据1951—2014年水文气候实测数据,运用Mann-Kendall检验法,以及蒸散发-断流天数和降水-径流双累积曲线统计模型等方法分析了长江中游荆南三口断流时间演变特征及其影响机制,结果表明：1）对各时期荆南三口平均断流天数而言,1951—2014年呈逐期増加趋势,且趋势性变化显著,而在2003—2014年间,断流天数虽也增加,但趋势性变化不显著,即增加趋势逐渐减缓;2）影响荆南三口断流天数增减変化的是径流变化过程,而导致径流变化的又是以降水和蒸散发为代表的气候因素和以水利工程、各行业（农业）用水为标志的人类活动;3）影响荆南三口断流天数持续增加的主要驱动因素是人类活动,以各自时段前一时段为基准期,1959—1966、1967—1972、1973—1980、1981—2002、2003—2014年的5个变异期中,气候波动对荆南三口断流天数增加的贡献率依次为24.93%、19.05%、6.36%、10.38%、7.56%;人类活动影响的贡献率分别为75.07%、80.95%、93.64%、89.62%、92.44%。     

Assessment of deep aquifer groundwater quality in a geographically unique climatic region of Southern Western Ghats,India using water quality indices

Water quality index (WQI) models are generally used in hydrochemical studies to simplify complex data into single values to reflect the overall quality. In this study, deep groundwater quality in the Chittur and Palakkad Taluks of the Bharathapuzha river basin of Kerala, India, was assessed by employing the WQI method developed by the Canadian Council of Ministers of the Environment (CCME). The assessment of overall water quality is indispensable due to the specific characteristics of the study area, such as geography, climate, over-drafting, and prevalent agricultural practices. Forty representative samples were collected from the study area for monsoon (MON) and pre-monsoon (PRM) seasons. The results showed a general increase of contents from MON to PRM. The major cations were spread in the order Ca²⁺>Na+>Mg²⁺>K⁺ and the anions HCO₃⁻>Cl⁻>CO₃²⁻ based on their relative abundance. Among various parameters analysed, alkalinity and bicarbonate levels during MON were comparatively high, which is indicative of carbonate weathering, and 90% of the samples failed to meet the World Health Organization (WHO, 2017)/Bureau of Indian Standards (BIS, 2012) drinking water guidelines. The CCME WQI analysis revealed that nearly 50% of the samples during each season represented good and excellent categories. The samples in the poor category comprised 10% in MON and 15% in PRM. The overall WQI exhibited 15% of poor category samples as well. The spatial depiction of CCME WQI classes helped to expose zones of degraded quality in the centre to eastward parts. The spatial and temporal variations of CCME WQI classes and different physicochemical attributes indicated the influence of common factors attributing to the deep groundwater quality. The study also revealed inland salinity at Kolluparamba and Peruvamba stations, where agricultural activities were rampant with poor surface water irrigation.