Recovery of Sediment Characteristics in Moraine,Headwater Streams of Northern Minnesota After Forest Harvest1

Merten, Eric C., Nathaniel A. Hemstad, Randall K. Kolka, Raymond M. Newman, Elon S. Verry, and Bruce Vondracek, 2010. Recovery of Sediment Characteristics in Moraine, Headwater Streams of Northern Minnesota After Forest Harvest. Journal of the American Water Resources Association (JAWRA) 46(4): 733-743. DOI: 10.1111/j.1752-1688.2010.00445.x Abstract: We investigated the recovery of sediment characteristics in four moraine, headwater streams in north-central Minnesota after forest harvest. We examined changes in fine sediment levels from 1997 (preharvest) to 2007 (10 years postharvest) at study plots with upland clear felling and riparian thinning, using canopy cover, proportion of unstable banks, surficial fine substrates, residual pool depth, and streambed depth of refusal as response variables. Basin-scale year effects were significant (p < 0.001) for all responses when evaluated by repeated-measures ANOVAs. Throughout the study area, unstable banks increased for several years postharvest, coinciding with an increase in windthrow and fine sediment. Increased unstable banks may have been caused by forest harvest equipment, increased windthrow and exposure of rootwads, or increased discharge and bank scour. Fine sediment in the channels did not recover by summer 2007, even though canopy cover and unstable banks had returned to 1997 levels. After several storm events in fall 2007, 10 years after the initial sediment input, fine sediment was flushed from the channels and returned to 1997 levels. Although our study design did not discern the source of the initial sediment inputs (e.g., forest harvest, road crossings, other natural causes), we have shown that moraine, headwater streams can require an extended period (up to 10 years) and enabling event (e.g., high storm flows) to recover from large inputs of fine sediment.     

An Aquifer Classification System and Geographical Information System-Based Analysis Tool for Watershed Managers in the Western U.S.1

Payne, Scott M. and William W. Woessner, 2010. An Aquifer Classification System and Geographical Information System-Based Analysis Tool for Watershed Managers in the Western U.S. Journal of the American Water Resources Association (JAWRA) 46(5):1003-1023. DOI: 10.1111/j.1752-1688.2010.00472.x Abstract: Aquifers and groundwater systems can be classified using a variety of independent methods to characterize geologic and hydraulic properties, the degree of connection with surface water, and geochemical conditions. In light of a growing global demand for water, an approach for classifying groundwater systems at the watershed scale is needed. A comprehensive classification system is proposed that combines recognized methods and new approaches. The purpose of classification is to provide groundwater professionals, policy makers, and watershed managers with a widely applicable and repeatable system that reduces sometimes cumbersome complex databases and analyzes to straightforward terminology and graphical representations. The proposed classification system uses basin geology, aquifer productivity, water quality, and the degree of groundwater/surface water connection as classification criteria. The approach is based on literature values, reference databases, and fundamental hydrologic and hydrogeologic principles. The proposed classification system treats dataset completeness as a variable and includes a tiered assessment protocol that depends on the quality and quantity of data. In addition, it assembles and catalogs groundwater information using a consistent set of nomenclature. It is designed to analyze and display results using Geographical Information System mapping tools.     

多瑙河流域国际合作实践与启示

多瑙河是世界上流经国家最多的国际河流,其国际合作的成功实践对世界其他国际河流的合作具有积极的示范和借鉴作用。通过分析和总结多瑙河国际合作历程和合作特点（包括多种合作机制并存互补;引入风险管理、公众参与和流域综合管理等先进理念促进全面合作;利用GIS及数据管理等现代技术手段实现信息资源共享;利用协商和司法手段和平解决国际争端等）,结合我国国际河流的特点和国际水法及国际河流合作的发展趋势,提出了对我国的启示：应加强国际河流相关方面的研究与合作（特别是航运与水电开发等）;应充分重视国际河流生态环境保护,生态环境保护和防洪越来越强调全流域的合作与协调;应坚持国际河流的开发利用与保护并举,走平衡发展之路;应根据各国际河流特点及地区条件,选择合适的管理合作模式.     

四环素高效降解酵母菌Trichosporon mycotoxinivorans XPY-10降解特性

Trichosporon mycotoxinivorans XPY-10是一株分离自抗生素制药厂的高效四环素降解酵母菌。为了建立该菌株降解四环素的适宜条件,分别研究了碳源、有机氮源、金属离子等营养物质及初始底物浓度、接种量、pH、温度、装液量、摇床转速等理化因素对菌体生长及四环素降解效率的影响。结果表明,菌株XPY-10生长的最适碳源和氮源分别为蔗糖和蛋白胨。在含有0．05％FeSO4的培养基中,菌株XPY—10降解四环素的适宜条件为：接种量2％,pH8,温度3422,装液量100mL（250mL三角瓶）,摇床转速180r／min。在此条件下,菌株XPY—10在7d内对初始浓度为600mg／L的四环素降解率为83．63％。本菌株对养殖废水及制药废水中四环素的污染治理有一定的应用前景。     

Engineered nanomaterials in rivers--exposure scenarios for Switzerland at high spatial and temporal resolution

Probabilistic material flow analysis and graph theory were combined to calculate predicted environmental concentrations (PECs) of engineered nanomaterials (ENMs) in Swiss rivers: 543 river sections were used to assess the geographical variability of nano-TiO₂, nano-ZnO and nano-Ag, and flow measurements over a 20-year period at 21 locations served to evaluate temporal variation. A conservative scenario assuming no ENM removal and an optimistic scenario covering complete ENM transformation/deposition were considered. ENM concentrations varied by a factor 5 due to uncertain ENM emissions (15%-85% quantiles of ENM emissions) and up to a factor of 10 due to temporal river flow variations (15%-85% quantiles of flow). The results indicate highly variable local PECs and a location- and time-dependent risk evaluation. Nano-TiO₂ median PECs ranged from 11 to 1′623 ng L⁻¹ (conservative scenario) and from 2 to 1′618 ng L⁻¹ (optimistic scenario). The equivalent values for nano-ZnO and nano-Ag were by factors of 14 and 240 smaller.     

三峡库区香溪河流域非点源营养盐输出变化的试验研究

综合三峡库区香溪河流域土地利用结构和水系特点,在三大支流出口处设置常规水质监测断面,于干流响滩处设置水文控制断面,通过断面水质水量监测,利用数字滤波法解析径流多源和污染多源,研究上游来流点源和非点源营养盐输出负荷变化。结果表明：受农业非点源污染影响,TN是高岚河（0788 mg/L）＞古夫河（0712 mg/L）＞南阳河（0567 mg/L）;南阳河受磷矿企业点源输入的影响,TP是南阳河（0323 mg/L）＞高岚河（0074 mg/L）＞古夫河（0053 mg/L）;断面流量与降雨量的相关系数〖WTBX〗R〖WTBZ〗2=0720 2;TN和TP非点源年负荷输出分别占总量的61%和40%的, 20100607次降雨径流监测分析发现此次降雨汇流期间营养盐TN和TP输出的非点源贡献率分别达752%和709%;营养盐负荷主要受径流量影响,TN和TP输出负荷与流量的相关系数分别是0963 6和0978 9     

东湖典型区域间隙水中营养盐的时空分布

以富营养化程度严重的浅水湖泊东湖为研究对象,通过持续采样调查,分析并比较了3个典型采样点柱状沉积物间隙水中营养盐的垂直分布和季节变化特征,结果表明东湖沉积物间隙水中营养盐浓度最高值一般出现在-5 cm以上,-5～-10 cm之间有一个快速降低的过程,-10～-26 cm之间趋于稳定,但也有小幅的波动;冬季间隙水中营养盐浓度明显低于其他季节,夏秋两季略高。分析认为沉积物间隙水中营养盐浓度受附近污染源直接影响较大,与上覆水水质有一定相关性,但不显著。间隙水中营养盐的季节变化主要因为冬季污染排放减少加速了间隙水中营养盐向上覆水的扩散、减少了水中营养盐在沉积物表层的沉积,以及温度降低导致微生物活动减少进而降低了有机物的矿化分解量。并且认为常规疏浚深度就可以有效移除东湖表层污染严重的沉积物     

HYDROLOGIC AND HYDRAULIC RESEARCH IN MOUNTAIN RWERS1

ABSTRACT: Although our current (1990) knowledge of hydrologic and hydraulic processes is based on many years of study, there are river environments where these processes are complex and poorly understood. One of these environments is in mountainous areas, which cover about 25 percent of the United States. Use of conventional hydrologic and hydraulic techniques in mountain-river environments may produce erroneous results and interpretations in a wide spectrum of water-resources investigations. An ongoing U.S. Geological Survey research project is being conducted to improve the understanding of hydrologic and hydraulic processes of mountainous areas and to improve the results of subsequent hydrologic investigations. Future hydrologic and hydraulic research needs in mountainous areas are identified.     

Long-term depletion of calcium and other nutrients in eastern US forests

Both harvest removal and leaching losses can deplete nutrient capital in forests, but their combined long-term effects have not been assessed previously. We estimated changes in total soil and biomass N, Ca, K, Mg, and P over 120 years from published data for a spruce-fir site in Maine, two northern hardwood sites in New Hampshire, central hardwood sites in Connecticut and Tennessee, and a loblolly pine site in Tennessee. For N, atmospheric inputs counterbalance the outputs, and there is little long-term change on most sites. For K, Mg, and P, the total pool may decrease by 2%–10% in 120 years depending on site and harvest intensity. For Ca, net leaching loss is 4–16 kg/ha/yr in mature forests, and whole-tree harvest removes 200–1100 kg/ha. Such leaching loss and harvest removal could reduce total soil and biomass Ca by 20%–60% in only 120 years. We estimated unmeasured Ca inputs from rock breakdown, root-zone deepening, and dry deposition; these should not be expected to make up the Ca deficit. Acid precipitation may be the cause of current high leaching of Ca. Although Ca deficiency does not generally occur now in acid forest soils, it seems likely if anthropogenic leaching and intensive harvest removal continue.     

REUSE OF DOMESTIC WASTEWATER FOR IRRIGATION IN ARID ZONES: A CASE STUDY1

ABSTRACT: The domestic sewage of the city of Beer-Sheva, Israel, which is located in an arid region, is treated in a series of facultative ponds. The treated effluent is stored temporarily in an open surface earthen reservoir (about 0.5 ± 10⁶ m³ in volume) and then used for irrigation. The effluent is applied via sprinkler and trickle irrigation systems. The main crops irrigated are cotton, wheat, alfalfa, and corn. Total cotton yield is over 5500 kg/ha, and the wheat grain yield is over 7500 kg/ha. The amount of effluent applied is about 6500 m³/ha for cotton (including preplant irrigation), and the wheat receives about 4500 m³/ha via irrigation and an additional 2000 m³/ha from precipitation. Due to the nutrient content in the effluent, the above yields are obtained without any additional fertilization.