河床含水系统对单环芳烃净化特征室内模拟

为了模拟长期排污河流中单环芳烃在地表水-地下水系统迁移转化规律以及不同含水介质和水动力条件对单环芳烃的净化特征, 室内土柱实验采用3种有代表性的天然砂土为研究对象, 以生活污水模拟纳污河流, 实验历时5个月.单环芳烃的自然净化作用主要发生在河床底下0.4m内, 垂直向下单环芳烃各组分浓度呈由高到低的分布特征; 粗砂对苯、甲苯和单环芳烃总量(TBETX) 总净化率分别为32.06%、21.39%和27.13%;中砂1分别为76.26%、81.40%、87.99%;中砂2分别为68.94%、74.41%、81.69%, 这表明, 河流污染初期河床底含水介质完全饱水, 含水介质颗粒尺寸越大, 对单环芳烃的净化率就越低, 单环芳烃容易迁移进入地下水中; 随着时间的延长, 河床底部淤泥层不断增加, 砂层中的水流处于非饱和状态, 淤泥层和含水介质系统对单环芳烃的净化能力较饱水流时大, 单环芳烃不容易迁移进入地下水.      

Geochemistry of volatile organic compounds in seawater: Mesocosm experiments with 14C-model compounds

A series of ten radiotracer experiments were conducted in controlled experimental ecosystems (mesocosms) to investigate the behavior of volatile organic compounds (VOC) in seawater. Time-series measurements of the redistribution of ¹⁴C-activity within several major pools—dissolved, particulate, intermediate metabolite, and CO₂—in the ecosystem made possible an evaluation of the rates of processes—volatilization, biodegradation, Sorption and sedimentation—acting to remove VOC from seawater in summer. The behavior of the model ¹⁴C-VOC fell into three categories. Aromatic hydrocarbons (benzene, toluene, naphthalene) were subject to both volatilization and biodegradation, with mineralization dominating in summer. Chlorinated C₂-hydrocarbons (tetrachloroethylene) and chlorinated benzenes (chlorobenzene, 1,4-dichlorobenzene, and 1,2,4-trichlorobenzene) were affected only by volatilization and were relatively resistant to biodegradation. Of all the model VOC studied, only aliphatic hydrocarbons (decane and octadecane) were sorbed onto suspended paniculate matter; however, the primary route of loss from the water column appeared to be biodegradation rather than sedimentation. The mesocosm-derived removal rate constants were then applied to estimate summer VOC residence times in Narragansett Bay, Rhode Island of about 1 day for aromatic hydrocarbons, 1 week for the chlorinated VOC and about 1 day for aliphatic hydrocarbons. Residence times in winter might be on the order of 1 week for all VOC.     

Geochemistry and provenance of bed sediments of the large rivers in the Tibetan Plateau and Himalayan region

We investigated the geochemical characteristics of major, trace and rare earth elements and Sr–Nd isotope patterns of bed sediments from the headwaters and upper reaches of the six large rivers draining the Tibetan Plateau (the Jinsha River—Yangtze, Lancang River—Mekong, Nujiang River—Salween, Huang He—Yellow, Indus, and Yarlung Tsangpo—Brahmaputra). By using Ca/Al versus Mg/Al, La/Sc versus Co/Th, and ⁸⁷Sr/⁸⁶Sr versus ε_Nd (0) binary differentiation diagrams of provenance, some typical contributors to the different catchment sediments can be identified. In the Three-River (the Jinsha, Lancang, and Nujiang Rivers) tectonomagmatic belt, acidic–intermediate-acidic volcanic rocks are very important provenance of sediments. Carbonate rocks and Permian Emeishan basalts are dominant in the Jinsha River. The Yellow River sediments have similar geochemical characteristics with loess in catchments. The Indus and Yarlung Tsangpo Rivers sediments are mainly from ultra-K volcanic rocks and Cenozoic granitoids widely distributed in the Indus–Yarlung suture. The intensity of chemical weathering in these river catchments is evaluated by calculating the chemical indices of alteration (CIA) of sediments and comparing them with bedrocks. The CIA values of the six river sediments are from 46.5 to 69.6, closing to those of bedrocks in the corresponding catchment, which indicates relatively weak chemical weathering intensity. Lithology, climate, and topography affect the chemical weathering intensity in these river catchments.     

Organic Contamination of Soil and Goundwater in the Piedimont Plain of the Taihang Mountains

The risk of groundwater contamination following the infiltration of waste surface water, is of great interest, particularly in areas experiencing water shortage. In this study, the distribution characteristics of contaminants along the Cihe River, in the piedimont plain of the Taihang Mountains, China, was investigated by measuring the soil and water samples. The main organic contaminants detected in different media include hydrocarbons, chlorinated hydrocarbons, polycyclic aromatic hydrocarbons, and pesticides. The main contaminants found in different media are mostly derived from the river water, which can be seen from the results of waste water from the river and groundwater, from the soil samples from different depth and distance of the profiles along the river. The distribution characteristics showed that there has been a natural attenuation of the contaminants from the river during their transportation through the soils and groundwater. The sorption of organic compounds to soil organic matter is thought to be a main mechanism of natural attenuation.     

Geochronology of priority pollutants in sedimentation zones of the Volga and Danube delta in comparison with the Rhine delta

Six sediment cores were taken in sedimentation zones of the Volga river (located in the southern part of the Russian Federation) and, additionally, 6 sediment cores were taken in several lakes (sedimentation zones) in the central and western part of the Danube delta in Romania. Priority pollutants (8 metals, 7 polychlorinated biphenyls and 10 polycyclic aromatic hydrocarbons) were determined in all samples of all cores. Present-day and historical levels of pollutants since the late 1930s were established through the use of radionuclide time tracers (¹³⁷Cs, ¹³⁴Cs). For the persistent metals and polycyclic aromatic hydrocarbons, trends in the concentration profiles during the last 5 decades are described. Low and hardly changing concentrations of As, Cu, Zn and all studied PAHs were observed during the last five decades in the sediments of the Volga river. Recently deposited sediments show slightly increasing levels for the heavy metals Zn and Cr and As in the Volga delta. For the studied metals and PAHs, maximum concentrations were found around 1987 in the sediments of the Danube delta. Sediments deposited around 1940 and recently deposited sediments in the Danube delta showed lower pollutant levels. If the contents of heavy metals, PAHs and PCBs in the aquatic sediments in the deltas of the rivers Rhine, Danube and Volga are compared, it is clear that the Volga delta is and was the cleanest delta during the last 5 decades. Nowadays the contents of heavy metals (except Cu and Ni), PAHs and PCBs in the aquatic sediments of the river Rhine are still highest compared to the other two rivers. The recent load of heavy metals (except Cd and Zn) in the sediments of the river Danube is the highest compared to the other two rivers.     

Behavior of Hydrocarbons in the Mouth Parts of Arctic Rivers

The paper reviews data (acquired in 2007–2016) on aliphatic and polycyclic aromatic hydrocarbons in comparison with data on concentrations of lipids, C_org, and chlorophyll a in the water and bottom sediments the river–sea geochemical barrier (for the Northern Dvina, Ob, Yenisei, and Lena rivers). It was established that the concentrations of anthropogenic hydrocarbons decrease and these compounds precipitate like other organic compounds and particulate matter, where riverine and marine waters mix. Relatively pure water flows in the pelagic zones of seas. In spite of low temperatures in the Arctic, anthropogenic hydrocarbons transform so rapidly that natural compounds dominate in the water and bottom sediments: autochthonous in the seawater and allochthonous in the bottom sediments.     

Composition of Hydrocarbons in Synthetic Diamonds Grown in a Fe—Ni—C System (according to Gas Chromatography—Mass Spectrometry Data)

The first data of chromatography—mass spectrometry analysis of volatiles from crystals of synthetic diamonds grown in a Fe—Ni—C system at 1350–1400°С and 5.5–6.0 GPa are presented. The composition of the fluid in equilibrium with the metal-carbon melt is determined, and a comparative estimation for the compounds of different hydrocarbons and their derivatives is made. It is shown that a significant role in these processes is played by high-molecular-weight hydrocarbons; and the total share of hydrocarbons and their derivatives in the fluid compounds can exceed 86%.     

Experimental mobilization of metals from aquatic sediments by nitrilotriacetic acid

Nitrilotriacetic acid (NTA) and other synthetic complexing agents have recently come into use as partial substitutes for polyphosphates in detergents. Large amounts of heavy metals are solubilized (“complexed”) when highly polluted river sediments are treated with solutions containing NTA. This could endanger the drinking-water supplies in areas using river and lake water.Our experiments with polluted river sediments (NTA concentrations 1–100 ppm; shaking time 10–200 hours) indicate a high percentage mobilization of heavy metals with copper, cadmium and — to a lesser extent — nickel showing a positive correlation with both concentration of NTA and time of shaking.The release of zinc and lead is positively correlated with NTA concentration but shows a negative correlation with time of shaking — possibly due to the biodegradation of the (less stable) Pb and Zn chelates. With chromium no mobilization at any concentration or with any time of shaking could be observed.     

Hydrocarbons of Surface Waters in the Transantarctic Section

Doklady Earth Sciences - The data obtained for 2015–2017 on the content and composition of aliphatic hydrocarbons (HCs) in particulate matter at the river–sea geochemical barriers (the...     

Aliphatic petroleum and biogenic hydrocarbons entering Narragansett Bay from tributaries under dry weather conditions

The temporal variability of hydrocarbon inputs from rivers discharging into Narragansett Bay under dry weather conditions, as well as the elucidation of the types and sources of hydrocarbons found in urban rivers, has been investigated. The rivers studied, the Blackstone, the Pawtuxet, the Moshassuck, and the Woonasquatucket, constitute the majority of river flow to the estuary. The unfiltered river water samples were extracted and analyzed for total aliphatic hydrocarbons, including natural and petroleum-derived species. The results of the year-long study revealed consistent oil pollution in all of the rivers sampled. Crankcase oil was ubiquitous, but the presence as well of fuel oils and, particularly in the Moshassuck River, gasoline (or kerosene), demonstrate that these rivers are subject to considerable oil pollution stress. The average concentration of hydrocarbons was ≈37 μg l^?1 which, according to some toxicologists, indicates that sensitive organisms may be under stress. In addition, most samples showed evidence of small amounts of terrigenous plant wax hydrocarbons. Hydrocarbon concentrations are comparable to those in other urban rivers but are higher than in rivers from rural areas; moreover, they did not vary in any systematic way with season. The mass transport of hydrocarbons in each of the rivers generally mimicked trends in river discharge, thereby emitting the lowest mass to the estuary in the summer and increasing throughout the remainder of the year. Moreover, due primarily to relative discharge differences, the Blackstone and Pawtuxet rivers constitute 90% of the total calculated flux of hydrocarbons from all four rivers. By combining the results from this investigation with those from previous studies, it was possible to obtain an estimate of the total annual inputs of these contaminants to Narragansett Bay. Total annual loads from rivers and wastewater treatment facilities were approximately 240 mt. When sources such as wet weather inputs were included, the total increased to 420 mt yr^?1. This value represents direct current inputs to the system and is considerably lower than previously published estimates. The current direct input estimate, while indicative of an improving situation, differs from previous estimates in that the latter were based upon calculations that approximated the long-term loadings from the watersheds, most of which are likely accumulating above the fall-lines of rivers throughout the watershed. Nevertheless, the current loadings represent a significant chronic flux of hydrocarbons to Narragansett Bay. For example, this estimate indicates that an amount equal to approximately 43% of the oil discharged into Narragansett Bay from the recent World Prodigy oil spill enters the estuary from chronic sources every year.     

Tidal river sediments in the Washington,D.C. area. II. Distribution and sources of organic contaminants

Concentration of aliphatic, aromatic, and chlorinated hydrocarbons were determined from 33 surface-sediment samples taken from the Tidal Basin, Washington Ship Channel, and the Anacostia and Potomac rivers in Washington, D.C. In conjunction with these samples, selected storm sewers and outfalls also were sampled to help elucidate general sources of contamination to the area. All of the sediments contained detectable concentrations of aliphatic and aromatic hydrocarbons, DDT (total dichlorodiphenyltrichloroethane), DDE (dichlorodiphenyldichloroethene), DDD (dichlorodiphenyldichloroethane), PCBs (total polychlorinated biphenyls) and total chlordanes (oxy-, α-, and γ-chlordane and cis + trans-nonachlor). Sediment concentrations of most contaminants were highest in the Anacostia River just downstream of the Washington Navy Yard, except for total chlordane, which appeared to have upstream sources in addition to storm and combined sewer runoff. This area has the highest number of storm and combined sewer outfalls in the river. Potomac River stations had lower concentrations than other stations. Total hydrocarbons (THC), normalized to the fine-grain fraction (clay + silt, < 63 μm), ranged from 120 μg g^?1 to, 1,900 μg g^?1 fine-grain sediment. The hydrocarbons were dominated by the unresolved complex mixture (UCM), with total polycyclic aromatic hydrocarbons (PAHs) concentrations ranging from 4 μg g^?1 to 33 μg g^?1 fine-grain sediment. Alkyl-substituted compounds (e.g., C1 to C4 methyl groups) of naphthalene, fluorene, phenanthrere + anthracene, and chrysene series dominated the polycyclic aromatic hydrocarbons (PAHs). Polycyclic aromatic hydrocarbons, saturated hydrocarbons, and the unresolved complex mixture (UCM) distributions reflect mixtures of combustion products (i.e., pyrogenic sources) and direct discharges of petroleum products. Total PCB concentrations ranged from 0.075 μg g^?1 to 2.6 μg g^?1 fine-grain sediment, with highest concentrations in the Anacostia River. Four to six C1-substituted biphenyls were the most-prevalent PCBs. Variability in the PCB distribution was observed in different sampling areas, reflecting, differing proportion of Arochlor inputs and degradation. The concentration of all contaminants was generally higher in sediments closer to known sewer outfalls, with concentrations of total hydrocarbon, PAHs, and PCBs as high as 6,900 μg g^?1, 620 μg g^?1, and 20 μg g^?1 fine-grain sediment, respectively. Highest PCB concentrations were found in two outfalls that drain into the Tidal Basin. Concentrations of organic contaminants from sewers draining to the Washington Ship Channel and Anacostia River had higher concentrations than sediments of the mid-channel or river. Sources of PCBs appear to be related to specific outfalls, while hydrocarbon inputs, especially PAHs, are diffuse, and may be related to street runoff. Whereas most point-source contaninant inputs have been regulated, the importance of nonpoint source inputs must be assessed for their potential addition of contaminants to aquatic ecosystems. This study indicates that in large urban areas, nonpoint sources deliver substantial amounts of contaminants to ecosystems through storm and combined sewer systems, and control of these inputs must be addressed.     

Distributions of pesticides and organic contaminants between water and suspended sediment,San Francisco Bay,California

Suspended-sediment and water samples were collected from San Francisco Bay in 1991 during low river discharge and after spring rains. All samples were analyzed for organophosphate, carbamate, and organochlorine pesticides; petroleum hydrocarbons; biomarkers; and polynuclear aromatic hydrocarbons. The objectives were to determine the concentrations of these contaminants in water and suspended sediment during two different hydrologic conditions and to determine partition coefficients of the contaminants between water and sediment. Concentrations of hydrophobic contaminants, such as polynuclear aromatic hydrocarbons, varied with location of sample collection, riverine discharge, and tidal cycle. Concentrations of hydrophobic contaminants in suspended sediments were highest during low river discharge but became diluted as agricultural soils entered the bay after spring rains. Polynuclear aromatic hydrocarbons defined as dissolved in the water column were not detected. The concentrations sorbed on suspended sediments were variable and were dependent on sediment transport patterns in the bay. In contrast, the relatively hydrophilic organophosphate pesticides, such as chlorpyrifos and diazinon, has a more uniform concentration in suspended sediment. These pesticides were detected only after spring rains. Most of the measured diazinon, at least 98% for all samples, was in the dissolved phase. Measured partition coefficients for diazinon generally were uniform, which suggests that suspended-sediment concentrations were close to equilibrium with dissolved concentrations. The concentration of diazinon sorbed to suspended sediments, at any given sampling site, was driven primarily by the more abundant solution concentration. The concentrations of diazinon sorbed to suspended sediments, therefore, were independent of the patterns of sediment movement.     

大型坳陷湖盆“洪水—河漫湖”沉积——以干旱背景下的松南泉四段为例

本文建立了一种干旱背景下坳陷湖盆全新的沉积充填模式,即"洪水—河漫湖"沉积模式。在干旱背景下,物源区的河流主要表现为季节性的洪水,大多数河流都消失在荒漠中,河水主要以地表蒸发、植被生态消耗、地下渗流、河流终端湖以及河漫湖等形式排泄,坳陷湖盆内并未形成统一大面积的汇水中心和湖相沉积。这种背景条件下,湖盆的沉积充填特征明显不同于经典的坳陷湖盆和浅水湖盆沉积。下白垩统泉头组四段沉积时期,松辽盆地具有气候干旱、地势平坦、生物单调贫乏等特征,盆地南部存在5大沉积体系及7条主要的水系。除在盆地西部古龙凹陷地区河流汇水形成小范围浅水湖泊外,在盆地南部主要为"洪水—河漫湖"的河流相沉积。坳陷湖盆"洪水—河漫湖"沉积具有以下特点:①全盆地没有统一的汇水中心,因而缺乏大面积分布的湖相和三角洲沉积;②河流表现为季节性的洪水,部分河流由于地形变缓,并未进入汇水中心,而是消失在荒漠中,河流相为盆地沉积充填的主要类型;③湖盆具有多物源、多漫湖、满盆含砂的沉积特点;④河漫湖与河流在空间分布上存在3种关系,即河流终止于河漫湖、河流穿过河漫湖、河流绕过河漫湖等。坳陷湖盆"洪水—河漫湖"是一种中—新生代陆相坳陷湖盆沉积充填的新模式,具有重要的理论和实践意义。     

基于遥感影像分析1989—2019年黄河内蒙古段河冰时空变化

获取河冰时空分布信息对黄河流域防凌减灾工作及沿岸地区可持续发展具有重要意义。收集黄河内蒙古段1989—2019年冬季河冰遥感影像数据;提出了归一化未封冻水体指数（NDUWI）用以剥离被归一化雪指数（NDSI）误分为河冰的水体像元,确定了该指数划分河冰、水体像元的阈值,并利用NDUWI结合NDSI的方法提取河冰信息进而分析河冰时空分布及变化特征,探讨了海勃湾水库调度及河床演变对河冰分布的影响。结果表明：黄河内蒙古段河冰主要分布在研究区中游（巴彦高勒—三湖河口）。1989年以来,研究区内河冰经历“平稳期”（1989—1997年）、“扩张期”（1998—2000年）、“萎缩期”（2001—2019年）3个阶段,其中2000年出现河冰面积峰值,并于2019年减小至最小。各子段中,海勃湾至巴彦高勒（R1段）2015年前河冰分布稳定,2015年起受海勃湾水库建成影响,河冰面积大幅萎缩;巴彦高勒至头道拐（R2~R4段）河冰面积变化特征大体与全段变化相同。空间上,2015年后R1段以纵向萎缩为主,巴彦高勒至三湖河口（R2段）左岸河冰萎缩,右岸河冰堆积仍有偎堤风险;三湖河口至包头（R3）段全段河冰漫滩现象严重,2016年起得以缓解;包头至头道拐（R4）段以局部漫滩为主,2016年开始以主槽封冻为主。上游海勃湾水库建成后的常规运用可有效减小下游黄河内蒙古段的河冰漫滩现象。研究成果可为黄河内蒙古段水库防凌调度及堤防安全隐患排查提供参考。     

Sediment characteristics in the vicinity of the pulliam power plant,green bay,Wisconsin

Textural characteristics — mean, dispersion, and skewness — and heavy metal concentrations — Cr, Ni, Cu, Zn, Cd, and Hg — were determined for 41 bottom grab samples collected during July, 1973, at the mouth of the Fox River proximate to a coal-fired electric generating plant. The principal sediment types identified were very fine sand \((\bar x = 3.08\phi )\) and medium silt \((\bar x = 5.54\phi )\) . Irregular sediment distribution patterns along the western bank of the river reflect the complex interaction of the river currents and the orthogonally injected thermal effluent. Beyond the influence of the discharge plume, a more regular trend of sediment dispersal was identified. Sedimentary processes operative within this shallow environment are subject to considerable modification by wind-induced turbulence. The levels of Cr, Cu, Zn, and Cd were two to four times more concentrated in the Recent sediments than in the underlying glaciolacustrine deposits of red (Valders) clay. Ni concentrations were generally low while Hg was 15 to 35 times higher than background levels. Heavy metals were more concentrated in the fine-grained sediments of the river and shipping channel than in the coarser fractions along the river banks and nearshore environments of the lower Bay. The thermal effluent of the power plant has local but significant physical effects on the sediments in the vicinity of the discharge outlet. The chemical character of the sediments is established principally through upstream sources in the Fox River.     

三维全扫描荧光法探讨长江口邻近陆架有机沉积物来源

近年发展起来的三维全扫描荧光光谱主要由硬件PE650-40荧光分光计,PE-3600数据站和PE-660打印画图机和专用“SCANR”软件组成.激发和发射波长分别在220-600nm范围内进行全自动,交替,连续地扫描,以发射/激发波长和荧光强度的三维全扫描荧光光谱图,以及它们的等高线图来描述测量结果,用该项新技术研究东海长江口海域表层沉积物中多环芳炷浓度和它们的环数分布特征,还讨论了具有典型陆源高等植物特征的苝的浓度分布特征,结果表明沉积物中有机质主要来自长江入海陆源物随远离河口递减,在东经123°以西附近出现最高浓度值.     

太湖宜溧河水系沉积物中多环芳烃来源解析

利用索氏提取技术和GC／MS测定，分析了太湖定溧河水系中13个样点沉积物中的多环芳烃（PAHs)，并利用芳香类不可分辨鼓包峰的检出、多环芳烃组分协相关因子检验及PAHs特征化合物指数，分析了太湖流域宜溧河水系中各地区的PAHs污染来源差异，并结合定溧河所在地区工业布局和环境特征得到了验证。溧阳附近PAHs主要来自于油类污染和染料工业的影响；宜兴市附近PAHs来源与溧阳不同，主要与现代煤烟型污染有关。从水第的干支流对比中发现，主干河道中沉积物PAHs污染来源比支流复杂的多，存在多种污染源交叉作用的情况。     

Sources and transports of polycyclic aromatic hydrocarbons in the Nanshan Underground River,China

Karst areas have much higher ecological vulnerability and are easy to be contaminated by polycyclic aromatic hydrocarbons (PAHs), which are introduced as health risk pollutants. PAHs ratios were used to understand the sources and transport behavior of PAHs conducted in the karst Nanshan Underground River, China. Water, sediments from the underground river and water, sediments, soil from the surface were collected monthly in 2011 and 2012. Abundant PAHs were found both in the underground river and in the surface system. The detected ΣPAHs concentrations varied from 353 to 13,203 ng L^?1 in the groundwaters and content from 169 to 12,038 ng g^?1 in the sediments of the underground river. The ratios of anthracene to anthracene, plus phenanthrene and fluoranthene to fluoranthene, plus pyrene indicated that PAHs were delivered in the groundwaters from combusted grass, wood, and coal, while in the sediments were a mixture of non-combusted petroleum, grass, wood, coal and combusted grass, wood, coal. The similarities in sources between an underground river and surface system indicated that farmlands play a major role for the transport of PAHs and contamination in the underground river. Karst features are liable for the transport behavior.     

From flood control to flood adaptation: a case study on the Lower Green River Valley and the City of Kent in King County,Washington

Despite massive investment in flood control infrastructure (FCI), neither cities nor rivers have been well served—flooding continues to challenge cities around the world, while riverine ecosystems are degraded by FCI. Although new flood hazard management concepts have shifted the focus away from FCI, many cities continue to count on FCI to prevent flood damage. It is assumed that existing built-up areas can only count on FCI, as large-scale retreat is often impossible. However, flood adaptation—retrofitting the built environment to prevent damage during flooding—as an option is often ignored. This paper argues against the continual use of FCI to prevent flood damage by reviewing FCI’s established problems. The paper examines human–river interactions associated with FCI, focusing on the feedback mechanisms in the interactions, with a case study on the Lower Green River (LGR) valley in King County, Washington, USA. An urban ecology research model is employed to organize the case study, where interactions between floodplain urbanization, FCI, flow and sediment changes, flood risk, and riverine ecosystem are explored and two feedback mechanisms—river adjustment and flood risk perception—are explicitly addressed. The resulting complex dynamics, in terms of cross–scale interactions, emergence, nonlinearity, and surprises, are synthesized and limitations of FCI outlined. Flood adaptation is explored as a plausible alternative to flood control to nurture flood resilience. A management scenario of flood adaptation for the City of Kent—the largest municipality in the LGR valley—is developed to discuss the implications of flood adaptation on flood risk and river restoration.