A Comparison of Metabolic Rates in Off‐Channel Habitats of the Middle Mississippi River

Autochthonous material has been found to be an important base in large river food webs. However, a spatial understanding of primary production in large rivers is lacking. We modeled primary productivity and community respiration (CR) during a low water period in two types of off‐channel habitat present in the Middle Mississippi River, side channels and wing dike fields. Wing dike fields are constantly connected to the main channel and are well mixed along most of their length, while side channels are typically connected only at the top and mouth. Gross primary production (GPP) in wing dike fields ranged from 0.0 to 8.9 g O₂ m^?2 D^?1 and in side channels GPP ranged from 0.4 to 33.5 g O₂ m^?2 D^?1. Both habitat types experienced periods of positive net ecosystem production (NEP) especially in the late summer and early fall. Correlations between metabolic rates and ecosystem characteristics differed between habitat types. Discharge was negatively correlated to NEP in wing dike fields but was not associated with metabolic rates in side channels. Light was positively correlated with GPP and CR at both site types and with NEP in side channels. These areas are protected from high velocity and likely experience greater light penetration, allowing more photosynthesis to take place especially during low water periods. This study demonstrates the potential for high productivity in off‐channel habitats that are permanently connected to the main channel. Copyright © 2016 John Wiley & Sons, Ltd.     

The Importance of Shallow‐Low Velocity Habitats to Juvenile Fish in the Middle Mississippi River

Habitat management is a crucial aspect of fisheries management. Without knowledge of habitat associations, fisheries scientists are unable to effectively make habitat conservation or restoration recommendations. This becomes especially prominent when trying to manage commercially harvested populations and protect threatened or endangered species. To determine juvenile fishes habitat associations in the Middle Mississippi River, we analysed mini‐trawl catch data of six common juvenile fish species: blue catfish (Ictalurus furcatus), channel catfish (Ictalurus punctatus), channel shiner (Notropis wickliffi), freshwater drum (Aplodinotus grunniens), paddlefish (Polyodon spathula), and shovelnose sturgeon (Scaphirhynchus platorynchus). Overall, we conducted 2251 mini‐trawl sampling efforts between 2002 and 2013, resulting in the capture of 23,742 target specimens. Catch per unit effort was evaluated by structural habitat (i.e. velocity, depth, and substrate). Overall, these data suggest that juvenile fish species are more prevalent in shallow water and slower velocities. Ultimately the information garnered during this evaluation should be incorporated when considering habitat modifications, especially those modifications that impact the availability of shallow‐low velocity habitats. Copyright © 2016 John Wiley & Sons, Ltd.     

Fish Associations among Un‐notched,Notched and L‐head Dikes in the Middle Mississippi River

Wing dikes and other anthropogenic modifications have heavily altered riverine ecosystems. Recent efforts to reach a compromise between the needs of the river transportation industry and natural resource conservation include dike modification. Dike notching permits water flow through the landward portion of the dike and has been purported to provide suitable habitat for fish and other river biota while maintaining the navigation channel. L‐head dikes are flow‐control structures that create calm backwater‐like habitats downstream. However, few researchers have examined the actual effects of dike notching on water quality or fish communities. We compared standardized catch per unit effort and overall community structure for 50 fish species among un‐notched dikes, notched dikes and L‐head dikes in the Middle Mississippi River, sampled as part of the US Geological Survey's Long‐Term Resource Monitoring Program. There were no differences in standardized catch per unit effort for 64% of the fishes examined. Five species known to be associated with lotic habitats were most abundant near L‐head dikes. Seven species were more abundant at un‐notched dikes than notched dikes, while six species were more abundant at notched dikes than un‐notched dikes. Non‐metric multidimensional scaling suggested differences in overall fish community structure between un‐notched and other dike types. Detailed physical habitat studies should be conducted to better understand the effects of dike modification. Copyright © 2015 John Wiley & Sons, Ltd.     

Impacts of the Mississippi River spillway opening on faecal coliform concentration in Lake Pontchartrain

This study focuses on explaining the role of the periodic opening of the Bonnet Carré Spillway on the faecal coliform levels in Lake Pontchartrain. Water quality data were collected by the Lake Pontchartrain Basin Foundation to analyse the faecal coliform bacteria levels, turbidity, salinity, temperature, and dissolved oxygen in the lake water. The results show that the faecal coliform concentrations were lower during the spillway opening than the preceding and subsequent months. Statistical analysis shows the dilution effect, characterized by an effective reduction in faecal coliform concentrations due to increase in water turbidity, coupled with decrease in water salinity and dissolved oxygen because of spillway opening. It is also indicated that the combine effect of more than one factor produces a significantly greater reduction in the faecal coliform than each factor acting independently. Periodic spikes in faecal coliform concentrations were observed at sampling points located near the outlets of streams and drainage canals with high settlement densities. A positive correlation (r = 0.78467) was found between the average faecal coliform counts and average monthly precipitations, highlighting the role of precipitation run‐offs. The results of this study indicate that the spillway opening contributed to a reduction in the faecal coliform concentration in the lake's surface water during the studied periods.     

Nutrient Contributions from Alluvial Soils Associated with the Restoration of Shallow Water Habitat in the Lower Missouri River

The Missouri River has been extensively altered as the result of channelization, bank stabilization, and the construction of six main stem reservoirs. In response to the resultant habitat loss, the US Army Corps of Engineers was tasked with restoring approximately 8100 ha of shallow water habitat (SWH), in part, for the benefit of the endangered pallid sturgeon (Scaphirhynchus albus). Construction of off‐channel habitats involves the removal and disposal of excavated alluvium either by direct discharge into the river or by secondary erosion, which raised concerns regarding the introduction of sediment and associated nutrients into the Missouri River. Soils from nine side‐channel chutes were sampled to represent nutrient concentrations from habitat restoration activities. Soils from 12 historically undisturbed sites were also sampled to represent reference conditions in the Missouri River flood plain. The results of this study indicate that nutrient characteristics of soils from selected SWH locations generally are similar to those of historically undisturbed soils. The estimated mass of total phosphorus from chutes accounted for 1.9% of Missouri River and 0.5% of Mississippi River total phosphorus loads during the 1993–2012 analysis period. The mass of nitrate, the constituent most closely related to gulf hypoxia, was 0.01% or less of the Missouri and Mississippi River nitrate loads. Sediment volumes from the chutes accounted for 3.1 and 1.5% of total suspended loads from the Missouri and Mississippi Rivers. Overall, the introduced sediment from side‐channel chute construction associated with SWH restoration accounts for a small portion of total nutrient and sediment transport in the Missouri and Mississippi Rivers. Published 2014. This article is a U.S. Government work and is in the public domain in the USA. River Research and Applications published by John Wiley & Sons, Ltd.     

Magnitude-frequency analysis of sediment transport in the lower Mississippi river

Magnitude-frequency analysis of gauging station records (1950-1982) on the Lower Mississippi shows that there is a clearly defined dominant flow of about 30000 m³ /s. This lies within an effective range of channel-forming flows between 17000 and 40000 m³ /s, which are responsible for transporting a disproportionately large percentage of the sediment load. The 33 year period of record is sufficiently long that the occurrence of an extreme high flow event does not significantly change these results. Hydrographic survey data, long-profile records and stage-discharge relationships from calibrated one-dimensional flow models indicate that the dominant discharge corresponds to ‘bar-full’ discharge on the Lower Mississippi and that the effective range of flows occurs between the stage that just tops mid-channel bars and that which significantly overtops the banks. Historical trends in bar growth suggest that bar-top elevations have generally risen to the dominant flow elevation over the last 30 years. In this trained river, where most of the banks are protected by revetments and the alignment is fixed by groynes and spurs, the mid-channel bars represent the major, contemporary morphological feature of the alluvial river.     

2005—2010年渭河主要支流水质变化趋势

根据2005—2010年渭河支流水质监测资料,对渭河陕西段10条主要支流水质有机污染指标DO、CODMn、NH3-N和BOD5的变化趋势进行了分析研究。结果表明:近6 a来渭河10条主要支流有机污染综合指数均呈下降趋势,渭河支流水质有所好转。各支流中,西安、渭南段支流水质改善显著,但西安段个别支流污染仍较严重,还需进一步改善。4种水质有机污染指标中氨氮污染水平仍为最高。分析了近6 a来渭河流域支流水质改善的原因:一是着力加强污染企业环境监督检查,初步遏制了环境污染恶化趋势;二是环保基础设施建设步伐加快,城镇生活污染问题得到一定的解决。     

Responses of consumers and food resources to a high magnitude,unpredicted flood in the upper Mississippi River basin

The Mississippi and Missouri Rivers experienced flooding in 1993 that fell outside the annual predictable flood period of spring and early summer. Flooding began in late June, peaked in late July (25 232 m³/s on the upper Mississippi and 21 240 m³/s on the Missouri) and remained at or near flood stage into October 1993. This study was performed to determine if disturbance by an unpredicted flood event would alter trophic dynamics of river–floodplain systems by creating shifts in the composition of organic matter available to consumers. The Ohio River, which did not flood during the same period, was examined for comparison. Stable isotopic ratios of carbon and nitrogen from samples collected in 1993 and 1994 were used to characterize potential food sources and determine linkages between food sources and invertebrate and fish consumers. Pairwise contrasts, performed separately for each river, indicated there were few interannual differences in δ¹³C and δ¹⁵N of organic matter sources and consumers. Between sample period (flood year versus normal water year) trends in both flooded rivers were similar to between‐year trends observed for the Ohio River. Trophic structure of the Mississippi and Ohio Rivers was similar in both years, with fine and ultra‐fine transported organic matter and dissolved organic matter representing the major sources of organic matter. Overlapping isotopic signatures in the Missouri River made tracking of sources through the consumers difficult, but similarities in δ¹³C and δ¹⁵N between years indicated trophic structure did not change in response to the flood. The results suggest that consumers continued to rely on sources of organic matter that would be used in the absence of the unpredicted 1993 flood. It is proposed that trophic structure did not change in response to flooding in the Mississippi and Missouri Rivers because both rivers exhibited the same trends observed in the Ohio River. Copyright © 2001 John Wiley & Sons, Ltd.     

The Historical Struggle with Floods on the Mississippi River Basin

For the past 150 years a titanic struggle has been underway between the people of the Mississippi River basin and its floods. Humans first tried to control the floods with structures, channel straightening, levees, dams, and reservoirs, but after 100 years and the expenditure of billions of dollars; losses to property and lives continued to grow. Efforts since the 1950s to encourage land-use changes in flood-prone areas and the use of flood insurance often have been thwarted by government relief and continuing human desire to reside in floodplains. During the massive floods in 1993, 1996, and 1997 only ten percent of the residents of flooded areas had flood insurance. The river system brings enormous economic value to the United States, and interests in protecting and enhancing the natural environment of the river are often in direct conflict with economic interests. Flood mitigation is often caught in the middle of the debate about how to manage the river system to satisfy all interests. Recent floods have taught several key lessons about environmental blessings and dangers, and reveal that the nation's policies regarding flood mitigation/relief must change with more emphasis on personal responsibility. The huge and costly infrastructure built to control the major rivers for floods and navigation is aging and will soon need replacement, offering an opportunity to better handle future flood mitigation to satisfy the basin's complex mix of economic, human, and environmental interests.     

Habitat suitability modeling of a conservation-significant fish species of the Kosi River,Uttarakhand, India

Water quality plays a vital role in the sustenance of aquatic life, including fish. Therefore, an inclusive understanding of water quality parameters can be considered an essential step in framing the conservation and management strategy of an aquatic ecosystem. This study examines the habitat suitability of a conservation-significant fish, the Tor putitora, and two associated fishes, the Labeo dyocheilus and the Garra gotyla, in relation to the water quality parameters of the Kosi River. Four crucial water quality parameters, water temperature, dissolved oxygen, electrical conductivity, and pH, were included in the QUAL2K modeling. Furthermore, hydrological processes were modeled using the soil and water assessment tool, and flow was used as an input in the QUAL2K model. The simulated water quality was correlated with fish habitat and analyzed through the analytical hierarchical process (AHP). Results suggested that the habitats of the Kosi were more suitable in the post-monsoon rather than pre-monsoon. Tor putitora, the flagship species of the Kosi, preferred the river habitats with a lower water temperature and higher dissolved oxygen for spawning. Thus, we recommend securing such habitats and managing them in collaboration with local communities for the long-term conservation of this endangered Himalayan species.     

城市特色滨水走廊——江油市涪江滨水景观规划设计

滨水景观规划设计是当前城市景观规划的一个重要内容,其工程的综合性和复杂性也使得该类工程极具挑战性。本文以江油市涪江两岸的景观设计为例,就如何进行城市特色滨水走廊的景观设计展开了探讨。     

海河流域水污染现状与水资源质量状况综合评价

海河流域在我国国民经济中占有举足轻重的地位。水污染及水环境恶化、水资源短缺 ,已成为制约本流域经济进一步发展、影响人民生活稳定的社会问题。对海河流域水污染现状与水资源质量状况进行了综合评价 ,初步分析论述了水污染造成的恶果和危害 ,以及应当采取的水环境保护措施     

瓜径港水质状况及其变化趋势分析

根据1997~2006年的水质监测结果,选用4个主要污染指标,采用综合污染指数法分析瓜径港近10年来水质状况及变化趋势。结果表明:瓜径港水质在这10年来基本呈恶化趋势,导致污染加重的主要因子是氨氮、总磷、高锰酸盐指数。主要原因是太湖流域经济迅速发展,人口猛增,用水量和工业、生活污水排放量增多,尤其是生活污水得不到有效处理,化肥、农药的使用和过量水产养殖也是水环境恶化另一原因。预计未来随着经济发展,瓜径港水体污染还会加重,所以必须严格控制污水排污量和建立完善污水处理系统。     

论淮河流域水污染及其防治

以淮河流域水污染的主要污染指标高锰酸盐指数和氨氮评价淮河流域的水污染状况,分析淮河干流、省界监测断面和全流域历年水质变化情况,结合入河排污口的实测资料,评价主要河流以及流域内河南、安徽、江苏和山东四省入河污水量和主要污染物的变化情况。基于流域内已发生的水污染事故、现状水质和入河污染物的状况,简要分析淮河流域水污染防治面临的困难,结合流域经济发展水平和水资源开发利用现状,对水污染防治与水资源保护需研究的主要问题进行了讨论。     

Analysis of water level management on the upper Mississippi River (1980–1990)

Management at 27 low-head dams affects water surface elevations for a 1050km stretch of the Upper Mississippi River (UMR) between St Louis, Missouri and Minneapolis, Minnesota. A systemic overview is given of current operating plans at dams on the UMR and historical data are analysed to determine how well the operating plans are being met. Water level elevations at all 27 dams are regulated as a function of discharge, although plans are specific for each dam. The management objective is to maintain a target water level at specific locations (control point) in each impoundment over specific ranges of discharge. The target water level and control point may change as discharge changes in each impoundment. In some of the impoundments water regulation causes drawdowns below the elevation for which the dams were planned, and at other dams no drawdown occurs. During the navigation seasons of 1980 to 1990, water levels were within their target window for an average of 72·5% of the time for 25 dams analysed. Difficulties in meeting targets are caused by winds, local rainfall events, ice dams and rapidly fluctuating discharges from tributaries with upstream reservoirs used for peaking hydropower.     

基于综合水质标识指数法的湟水水质评价

综合水质标识指数法是一种既相对简单又能综合反映河流水质整体水平的方法。采用综合水质标识指数法对2000—2010年湟水干流4个断面的水质监测数据进行评价,结果表明:湟水各断面的综合水质类别达到或优于水功能区的目标要求。将综合水质标识指数法评价结果与国标推荐的单因子标识指数法评价结果进行比较表明,单因子标识指数法评价结果(水质类别)要差于综合水质标识指数法评价结果,表明单因子标识指数法以最差的水质类别作为水质综合评价的结果,不能全面反映水质的整体状况,而综合水质标识指数法能综合反映河流水质的整体状况。     

黄河流域水资源需求管理初探

在对水资源需求管理的内涵和实施手段进行探讨的基础上,针对目前黄河流域水资源紧缺与用水效率低下的突出矛盾,分析了黄河流域实施需求管理的必要性。从行政管理、水价制定、经济激励、节水技术推广等方面提出了对策,对黄河流域实施水资源需求管理提出了初步建议。     

Cumulative effects of restoration efforts on ecological characteristics of an open water area within the Upper Mississippi River

Ecological restoration efforts in large rivers generally aim to ameliorate ecological effects associated with large‐scale modification of those rivers. This study examined whether the effects of restoration efforts—specifically those of island construction—within a largely open water restoration area of the Upper Mississippi River (UMR) might be seen at the spatial scale of that 3476 ha area. The cumulative effects of island construction, when observed over multiple years, were postulated to have made the restoration area increasingly similar to a positive reference area (a proximate area comprising contiguous backwater areas) and increasingly different from two negative reference areas. The negative reference areas represented the Mississippi River main channel in an area proximate to the restoration area and an open water area in a related Mississippi River reach that has seen relatively little restoration effort. Inferences on the effects of restoration were made by comparing constrained and unconstrained models of summer chlorophyll a (CHL), summer inorganic suspended solids (ISS) and counts of benthic mayfly larvae. Constrained models forced trends in means or in both means and sampling variances to become, over time, increasingly similar to those in the positive reference area and increasingly dissimilar to those in the negative reference areas. Trends were estimated over 12‐ (mayflies) or 14‐year sampling periods, and were evaluated using model information criteria. Based on these methods, restoration effects were observed for CHL and mayflies while evidence in favour of restoration effects on ISS was equivocal. These findings suggest that the cumulative effects of island building at relatively large spatial scales within large rivers may be estimated using data from large‐scale surveillance monitoring programs. Published in 2010 by John Wiley & Sons, Ltd.     

主成分分析法在辽河水质评价中的应用

在水质评价中,表示某一流域水质量情况的指标众多,而不同的指标间往往存在不同程度的相关性。其中有些相关性甚至非常显著,这使它们提供的信息有可能发生重叠。运用主成分分析综合处理可以产生新的指标,而这些新的指标彼此互补相关又能综合反映水质的情况。通过应用主成分分析逐步降维综合处理的特性对辽河水质进行评价,对辽河4个断面的污染程度做了综合评价。然后再应用主成分分析法选取主要污染指标,结合迭代聚类模型对主成分分析得到的结果进行分类。