The physico-chemistry of tidal Elechi Creek in the upper Bonny Estuary was investigated to assess the toxicity of the water body as this could have adverse effects on the native organisms that form part of the ecosyst...The physico-chemistry of tidal Elechi Creek in the upper Bonny Estuary was investigated to assess the toxicity of the water body as this could have adverse effects on the native organisms that form part of the ecosystem and to evaluate the extent and magnitude of petroleum hydrocarbon and heavy metal concentration in the water body. Standard field procedures were adopted in sample collection while laboratory analysis was carried out also following standard methods. Parameters measured include pH, temperature, dissolved oxygen (DO), biological oxygen demand (BOD), electrical conductivity, salinity and total dissolved solids (TDS). Heavy metals namely Copper (Cu), Lead (Pb), Zinc (Zn), nitrate (NO3), sulphate (SO4), Ammonia (NH4), and Total Hydrocarbon Concentration (THC) in the surface water body were also determined on samples collected from five (5) sampling stations spread along the creek in both dry and wet seasons. The results showed that the surface water body is oligohaline with low acidity, pH values ranging from 6.2 to 7.6. Temperature varies from 27°C to 30°C. Dissolved Oxygen (DO) concentration ranges from 2.9 to 7.5 mg/l which is adequate for aquatic organism with Biological Oxygen Demand (BOD) values varying from 0.45 to 7.0 mg/l. The values of total dissolved solids (TDS) vary from 11,700 mg/l to 26,250 mg/l with the highest mean value obtained at the study station located downstream. The mean nutrient concentration showed that the study area is not eutropic. Anthropogenic activities were very high at the sites throughout the period of the study and may have resulted in the stress conditions of the area. Pollution trend along the study stations showed that no one station is unpolluted. The study recommends the introduction of enforceable and stringent waste management plans to highlight and discourage direct discharge of untreated waste and storm water runoff into an aquatic environment.展开更多
There are three major types of tidal channels along the coast of the Huanghe (Yellow) River Delta: tidal inlets, tidal creeks, and tidal channels developed from abandoned river channels. The tidal inlets develop mainl...There are three major types of tidal channels along the coast of the Huanghe (Yellow) River Delta: tidal inlets, tidal creeks, and tidal channels developed from abandoned river channels. The tidal inlets develop mainly in two areas with weak erosion and barrier islands. The tidal channels formed from abandoned river channels mainly developed in the area of the new delta lobes formed since 1934. Tidal creeks developed in the intertidal zone and distributed along almost all parts of the Huanghe River Delta coast, but their scales and features are different.展开更多
Detailed topographic maps of drainage divides surrounding the Jefferson County, Montana, Boulder River drainage basin were analyzed to determine the nature of drainage systems that preceded today’s Boulder River drai...Detailed topographic maps of drainage divides surrounding the Jefferson County, Montana, Boulder River drainage basin were analyzed to determine the nature of drainage systems that preceded today’s Boulder River drainage system and how the Boulder River drainage system evolved from those earlier drainage systems. The Boulder River studied here drains in a north, east, and south direction to the Jefferson River, which at Three Forks, Montana joins the north-oriented Madison and Gallatin Rivers to form the north-oriented Missouri River. The North American east-west Continental Divide surrounds the Boulder River drainage basin western half and mountainous drainage divides with the Jefferson and Missouri Rivers surround the drainage basin’s eastern half. More than 25 deep mountain passes are notched into these drainage divides and provide evidence of the regional drainage system that preceded the present day Boulder River drainage system. Analysis of pass elevations and of orientations of valleys leading in opposite directions from those mountain passes shows that prior to Boulder River drainage system development immense volumes of south-oriented water moving in anastomosing complexes of diverging and converging channels flowed across the Boulder River drainage basin area and that the Boulder River drainage system evolved as deeper channels progressively captured flow from shallower channels. While not documented in detail crustal warping probably raised Boulder River drainage basin areas relative to adjacent valleys and basins as capture events took place. A water source was not determined, but may have been from a large North American continental ice sheet, although Boulder River drainage basin evolution probably occurred while mid Tertiary sediments were filling adjacent valleys and basins.展开更多
A new Cenozoic geology and glacial history paradigm (new paradigm), fundamentally different from the accepted Cenozoic geology and glacial history paradigm (accepted paradigm), describes a thick North American contine...A new Cenozoic geology and glacial history paradigm (new paradigm), fundamentally different from the accepted Cenozoic geology and glacial history paradigm (accepted paradigm), describes a thick North American continental icesheet (located where continental icesheets are usually reported to have been) which by deep erosion and uplift of surrounding regions created and occupied a deep “hole” (the accepted paradigm does not see this thick ice sheet or the deep “hole”). Unusual erosional landform features in the southeast Oklahoma Pontotoc County region including the asymmetric Canadian-Red River drainage divide, a large escarpment-surrounded basin in which most south-oriented Clear Boggy Creek headwaters begin, and a large escarpment-surrounded upland on which the south-oriented Blue River begins, are used to test the new paradigm’s ability to use large and prolonged south-oriented melt water floods to explain previously unexplained or poorly explained detailed topographic map drainage system and erosional landform evidence. Numerous low points (referred to as divide crossings) indicate large and prolonged south-oriented melt water floods did flow across what is now the Canadian-Red River drainage divide (an interpretation also consistent with Clear Boggy Creek escarpment-surrounded basin and Blue River escarpment-surrounded upland shapes). The new paradigm described massive and prolonged melt water floods also account for previously unrecognized deep regional erosion (which is determinable from detailed topographic map evidence). East-oriented Canadian River valley headward erosion (from the Arkansas River valley) diverted the long-lived south-oriented meltwater floods to the Arkansas River valley and to what ultimately became the deep “hole’s” only southern exit. Previous southeast Oklahoma drainage history interpretations (made from the accepted paradigm perspective in which Rocky Mountain glacier melt water flowed to east-oriented rivers) do not provide adequate water volumes or flow directions to explain the detailed topographic map drainage system and erosional landform evidence, which the new paradigm’s massive and prolonged south-oriented melt water floods do explain.展开更多
The lower reach of the Red River between Winnipeg and Lake Winnipeg is very prone to ice jam flooding. The one- dimensional ice jam model RIVICE was implemented for this reach to better understand the processes leadin...The lower reach of the Red River between Winnipeg and Lake Winnipeg is very prone to ice jam flooding. The one- dimensional ice jam model RIVICE was implemented for this reach to better understand the processes leading to such events and to provide a tool to evaluate strategies for ice jam mitigation. The most downstream portion of this river stretch flows through a delta and marsh system which poses challenges in modelling ice jams in such an area of low-lying topography and river banks. Solutions to overcome these challenges are discussed in this paper and results of one such solution using water abstractions from the main channel are also presented. Abstractions are inserted in the model to represent under-ice leakage from the main channel to side channel storage and diversions (up to 65% in the Red River delta) and spillage into the delta floodplain.展开更多
千年来,黄河三角洲地区尾闾入海河道在大口河~淄脉沟之间频繁摆动,各时期行水河口形成的河口滩均有宽大的潮间地带,但从地貌-沉积发生学上并不具备潮滩的性质;当行水河道摆走后,原河口滩摆脱了河口径流水沙的直接作用而被"废弃&qu...千年来,黄河三角洲地区尾闾入海河道在大口河~淄脉沟之间频繁摆动,各时期行水河口形成的河口滩均有宽大的潮间地带,但从地貌-沉积发生学上并不具备潮滩的性质;当行水河道摆走后,原河口滩摆脱了河口径流水沙的直接作用而被"废弃"?在海洋动力的作用下向潮成海滩的方向发育,"废弃"的时间越长,潮滩发育得越成熟?黄河三角洲洲边大多数海岸,属于处在不同发育阶段的潮滩型海岸;三角洲的东北角海岸地处区域 M2分潮无潮点附近,被"废弃"的河口滩逐渐被盛行强风浪作用剥平形成浪蚀型海滩?因此,黄河三角洲洲边并存三元谱系海滩,即河口滩?潮成海滩(潮滩)和浪蚀海滩,它们各具有自身的特点?本文将三角洲岸线和潮水沟体系分维 D 作为指标,对三角洲海岸发育时空谱系作进一步探讨?计算分析表明,区域内岸线分维与潮滩发育的时间成正相关,特大高潮岸线尤为明显,如古代黄河三角洲岸段岸线的分维值 D 为 1.1356~1.1625,而近代黄河三角洲平均变化在 1.091~1.118 范围内?平均高潮岸线分维值 D 也有相应的一定程度的变化;对三角洲洲边不同发育年代( 100~103 a )的 23 个潮水沟体系进行 m 级分辩率分维值 D 测计结果显示,在行水河口滩区岸和发育时间短?潮差小的区段( 如浪蚀海滩 )沟系( 含潮水沟和径流水道 )的分维值 D 较小,?展开更多
文摘The physico-chemistry of tidal Elechi Creek in the upper Bonny Estuary was investigated to assess the toxicity of the water body as this could have adverse effects on the native organisms that form part of the ecosystem and to evaluate the extent and magnitude of petroleum hydrocarbon and heavy metal concentration in the water body. Standard field procedures were adopted in sample collection while laboratory analysis was carried out also following standard methods. Parameters measured include pH, temperature, dissolved oxygen (DO), biological oxygen demand (BOD), electrical conductivity, salinity and total dissolved solids (TDS). Heavy metals namely Copper (Cu), Lead (Pb), Zinc (Zn), nitrate (NO3), sulphate (SO4), Ammonia (NH4), and Total Hydrocarbon Concentration (THC) in the surface water body were also determined on samples collected from five (5) sampling stations spread along the creek in both dry and wet seasons. The results showed that the surface water body is oligohaline with low acidity, pH values ranging from 6.2 to 7.6. Temperature varies from 27°C to 30°C. Dissolved Oxygen (DO) concentration ranges from 2.9 to 7.5 mg/l which is adequate for aquatic organism with Biological Oxygen Demand (BOD) values varying from 0.45 to 7.0 mg/l. The values of total dissolved solids (TDS) vary from 11,700 mg/l to 26,250 mg/l with the highest mean value obtained at the study station located downstream. The mean nutrient concentration showed that the study area is not eutropic. Anthropogenic activities were very high at the sites throughout the period of the study and may have resulted in the stress conditions of the area. Pollution trend along the study stations showed that no one station is unpolluted. The study recommends the introduction of enforceable and stringent waste management plans to highlight and discourage direct discharge of untreated waste and storm water runoff into an aquatic environment.
文摘There are three major types of tidal channels along the coast of the Huanghe (Yellow) River Delta: tidal inlets, tidal creeks, and tidal channels developed from abandoned river channels. The tidal inlets develop mainly in two areas with weak erosion and barrier islands. The tidal channels formed from abandoned river channels mainly developed in the area of the new delta lobes formed since 1934. Tidal creeks developed in the intertidal zone and distributed along almost all parts of the Huanghe River Delta coast, but their scales and features are different.
文摘Detailed topographic maps of drainage divides surrounding the Jefferson County, Montana, Boulder River drainage basin were analyzed to determine the nature of drainage systems that preceded today’s Boulder River drainage system and how the Boulder River drainage system evolved from those earlier drainage systems. The Boulder River studied here drains in a north, east, and south direction to the Jefferson River, which at Three Forks, Montana joins the north-oriented Madison and Gallatin Rivers to form the north-oriented Missouri River. The North American east-west Continental Divide surrounds the Boulder River drainage basin western half and mountainous drainage divides with the Jefferson and Missouri Rivers surround the drainage basin’s eastern half. More than 25 deep mountain passes are notched into these drainage divides and provide evidence of the regional drainage system that preceded the present day Boulder River drainage system. Analysis of pass elevations and of orientations of valleys leading in opposite directions from those mountain passes shows that prior to Boulder River drainage system development immense volumes of south-oriented water moving in anastomosing complexes of diverging and converging channels flowed across the Boulder River drainage basin area and that the Boulder River drainage system evolved as deeper channels progressively captured flow from shallower channels. While not documented in detail crustal warping probably raised Boulder River drainage basin areas relative to adjacent valleys and basins as capture events took place. A water source was not determined, but may have been from a large North American continental ice sheet, although Boulder River drainage basin evolution probably occurred while mid Tertiary sediments were filling adjacent valleys and basins.
文摘A new Cenozoic geology and glacial history paradigm (new paradigm), fundamentally different from the accepted Cenozoic geology and glacial history paradigm (accepted paradigm), describes a thick North American continental icesheet (located where continental icesheets are usually reported to have been) which by deep erosion and uplift of surrounding regions created and occupied a deep “hole” (the accepted paradigm does not see this thick ice sheet or the deep “hole”). Unusual erosional landform features in the southeast Oklahoma Pontotoc County region including the asymmetric Canadian-Red River drainage divide, a large escarpment-surrounded basin in which most south-oriented Clear Boggy Creek headwaters begin, and a large escarpment-surrounded upland on which the south-oriented Blue River begins, are used to test the new paradigm’s ability to use large and prolonged south-oriented melt water floods to explain previously unexplained or poorly explained detailed topographic map drainage system and erosional landform evidence. Numerous low points (referred to as divide crossings) indicate large and prolonged south-oriented melt water floods did flow across what is now the Canadian-Red River drainage divide (an interpretation also consistent with Clear Boggy Creek escarpment-surrounded basin and Blue River escarpment-surrounded upland shapes). The new paradigm described massive and prolonged melt water floods also account for previously unrecognized deep regional erosion (which is determinable from detailed topographic map evidence). East-oriented Canadian River valley headward erosion (from the Arkansas River valley) diverted the long-lived south-oriented meltwater floods to the Arkansas River valley and to what ultimately became the deep “hole’s” only southern exit. Previous southeast Oklahoma drainage history interpretations (made from the accepted paradigm perspective in which Rocky Mountain glacier melt water flowed to east-oriented rivers) do not provide adequate water volumes or flow directions to explain the detailed topographic map drainage system and erosional landform evidence, which the new paradigm’s massive and prolonged south-oriented melt water floods do explain.
文摘The lower reach of the Red River between Winnipeg and Lake Winnipeg is very prone to ice jam flooding. The one- dimensional ice jam model RIVICE was implemented for this reach to better understand the processes leading to such events and to provide a tool to evaluate strategies for ice jam mitigation. The most downstream portion of this river stretch flows through a delta and marsh system which poses challenges in modelling ice jams in such an area of low-lying topography and river banks. Solutions to overcome these challenges are discussed in this paper and results of one such solution using water abstractions from the main channel are also presented. Abstractions are inserted in the model to represent under-ice leakage from the main channel to side channel storage and diversions (up to 65% in the Red River delta) and spillage into the delta floodplain.
文摘千年来,黄河三角洲地区尾闾入海河道在大口河~淄脉沟之间频繁摆动,各时期行水河口形成的河口滩均有宽大的潮间地带,但从地貌-沉积发生学上并不具备潮滩的性质;当行水河道摆走后,原河口滩摆脱了河口径流水沙的直接作用而被"废弃"?在海洋动力的作用下向潮成海滩的方向发育,"废弃"的时间越长,潮滩发育得越成熟?黄河三角洲洲边大多数海岸,属于处在不同发育阶段的潮滩型海岸;三角洲的东北角海岸地处区域 M2分潮无潮点附近,被"废弃"的河口滩逐渐被盛行强风浪作用剥平形成浪蚀型海滩?因此,黄河三角洲洲边并存三元谱系海滩,即河口滩?潮成海滩(潮滩)和浪蚀海滩,它们各具有自身的特点?本文将三角洲岸线和潮水沟体系分维 D 作为指标,对三角洲海岸发育时空谱系作进一步探讨?计算分析表明,区域内岸线分维与潮滩发育的时间成正相关,特大高潮岸线尤为明显,如古代黄河三角洲岸段岸线的分维值 D 为 1.1356~1.1625,而近代黄河三角洲平均变化在 1.091~1.118 范围内?平均高潮岸线分维值 D 也有相应的一定程度的变化;对三角洲洲边不同发育年代( 100~103 a )的 23 个潮水沟体系进行 m 级分辩率分维值 D 测计结果显示,在行水河口滩区岸和发育时间短?潮差小的区段( 如浪蚀海滩 )沟系( 含潮水沟和径流水道 )的分维值 D 较小,?