Origin of Mountain Passes across Continental Divide Segments Surrounding the Southwest Montana Big Hole and Beaverhead River Drainage Basins, USA

The evolution of southwest Montana’s Big Hole and Beaverhead River drainage basins is determined from topographic map evidence related to mountain passes crossing what are today high altitude drainage divides including North America’s east-west Continental Divide. Map evidence, such as orientations of valleys leading away from mountain passes (and saddles) and barbed tributaries found along the downstream drainage routes, is used to reconstruct flow directions of streams and rivers that once crossed the present-day high mountain divides. Large south-oriented anastomosing complexes of diverging and converging channels are interpreted to have eroded what are today closely spaced passes and saddles now notched into high mountain ridges. Water in those south-oriented channels is interpreted to have flowed across emerging mountains and subsiding basins. Headward erosion of deeper southeast-oriented valleys, assisted by crustal warping, concentrated south-oriented water in fewer and deeper valleys as the water flowed from southwest Montana into what are today Idaho and the Snake River drainage basin. Headward erosion of the Big Hole River valley between the emerging Anaconda and Pioneer Mountains, also assisted by crustal warping, reversed all Big Hole Basin drainage so as to create the north-, east-, and south-oriented Big Hole River drainage route. A final and even more major reversal of flow in the present-day north-oriented Montana Missouri River valley, with the assistance of additional crustal warping, next ended all remaining flow to Idaho and the Snake River drainage basin and reversed and captured all drainage in the present-day north-oriented Big Hole, Beaverhead, and Red Rock River drainage basins. The observed map evidence indicates that prior to the final flow reversal events, large volumes of south-oriented water flowed across southwest Montana’s Big Hole and Beaverhead River drainage basins.

A SYSTEMATIC STUDY ON LAND AND REGIONAL DEVELOPMENT OF THE TARIM RIVER DRAINAGE BASIN,XINJIANG PROVINCE,CHINA

A Systematic Study on Land (SSL), aiming at the investigation of the land complex, isone of the important parts of integrated physical geography. With systematic theory as guid-ance, the dissertaton carries out the comprehensive and systematic study of a series ofsubsystems like land classification, land structure analysis, comprehensive physicalregionalization, land evaluation, reasonable planning of land utilization as well as popula-

Land Use Land Cover Dynamics of Upper Benue River Basin, Nigeria

This study examined land use land cover (LULC) dynamics in Upper Benue River Basin, Nigeria. The study makes use of primary and secondary data. Landsat Imageries for the years 1981, 2001 and 2021 were used in the study. Supervised approach with maximum likelihood classifier was adopted for the classification and generation of LULC maps. Markov Cellular Automata model was used to predict the status of LULC of the catchment for year 2070. The findings of the study reveal remarkable changes in the land use land cover of the Upper Benue River Basin. The land cover has witnessed downward trend in the percentage area covered by vegetation and bare surface resulting in 15.4% and 2.6% losses respectively. The result of the findings reveals that the built-up area and rock outcrop has shown significant gains of 15.2% and 2.9% of the study area respectively. Water body has been stable with 0% change, though, it witnessed a marginal decline in 2001. The land use land cover change observed in the Upper Benue River Basin was as a result of anthropogenic factors characterized by deforestation, expansion of agricultural lands, overgrazing among others. Based on the findings, the study recommended controlled grazing activity, deforestation and indiscriminate fuelwood exploitation and improved agronomic practices in the basin.

FACILITATING REGIONAL SUSTAINABLE DEVELOPMENT THROUGH INTEGRATED MULTI-OBJECTIVE UTILIZATION, MANAGEMENT OF WATER RESOURCES IN THE LANCANG-MEKONG RIVER BASIN

The Lancnag Mekong River is the most important international river across China and Southeast Asia, If it is developed according to 'Great Mekong Subregional Cooperation Plan' [9] prepared by ADB, the area directly affected will be up to over 2.32 million km 2, the population over 220 million, and the natural environment, and socio-economic conditions within a large area will be greatly changed. 'Agreement on Cooperation for Sustainable Development of Mekong Basin' signed by the four riparian countries along the lower Mekong River on April 5, 1995 provides a new opportunity for sustainable development of the Basin. According to preliminary analysis, if the multipurpose utilization of the water resources is the target for carrying out integrated planning and management, and the efforts are made 1) to focus on energy exploitation on the Lancang River Mainstream and the tributaries of the lower Mekong River; 2) to build gated weirs at Tonle Sam; 3) to construct spillways at the Mekong Delta; 4) to facilitate flood dykes in big cities and on both banks of the mainstream which are concentrated with population and farmland and liable to be flooded, and 5) to strengthen networks for forecasting hydrological and meteorological conditions, then all problems such as power demand, irrigation, flood, salt water intrusion as well as acid water erosion to soil could be solved without constructing large cascaded stations and dams on the lower Mekong Mainstream. This will not only avoid input of great number of fund, large scale resettlement and land inundation, but also prevent aquatic organisms living in Mekong River from being injured due to dam construction, and promote the sustainable development of the Basin.

Drainage Basin Characteristics of Dhund River Basin, Eastern Rajasthan India, Using Remote Sensing and GIS Techniques

Morphometric analysis is mathematical evaluation and measurement of the earth’s shape, surface and its landform’s dimension. Morphometric analysis of Dhund river basin in Jaipur district of Rajasthan India has been carried out to evaluate various morphometric parameters following the linear, areal and relief aspects. The drainage basin, which covers a total area of about 1828 km2 lies in eastern part of the district with maximum and minimum elevation of 603 m and 214 m respectively. Morphotectonic parameters like Hypsometric Integral, Sinuosity index and Asymmetry Factor have also been computed to identify the tectonic characteristics of the drainage basin. Primary and secondary data such as SOI topographic map, Cartosat-1 DEM and other relevant data were utilized. ArcGIS software (Arc Map 10.2) was used for geo-referencing of topographic maps, delineation of watershed and preparation of DEM, slope and drainage network. The basin is 6th order drainage basin having dendritic pattern of drainage network. A relatively lower mean value of Bifurcation ratio suggests that the drainage basin is formed by uniformed materials. Drainage basin area has little elongated shape and is less prone to floods. Basin has different erosional stages and levels of tectonic activity, Moderate Meandering and unstable setting.

A decade of variation of COD in the Changjiang River (Yangtze River) and its variation trend analysis

The average annual value of COD (chemical oxygen demand) fluxes of the Changjiang River (Yangtze River) and its main tributaries in the past decade (i.e., 1991–2000), has been evaluated. Based on the data from the Datong Hydrological Station (DHS), it was found that the Dongting Lake drainage basin contributed the greatest water discharge (35.8%) and COD flux (48.3%) among the main tributary drainage basins, followed by the Poyang Lake drainage basin with the contributions of 15.4% and 19.3%,respectively. By the end of the year of 2000, COD flux in the Changjiang River rose by almost 45% relative to that in the year of 1991, reaching about 1941000 ton/a at DHS. Statistical analysis revealed that industrial wastewater discharge, as well as COD in it, was found decreasing in the same period, due to the gradual reinforcement of environmental management. Moreover, correlation analysis indicated that non-point pollution from agriculture and increasing discharge of domestic sewages caused by rapid growth of population along the Changjiang River drainage valley should be responsible for the high COD. Furthermore, with the current trend of population growth and agricultural development in this basin, water quality of the Changjiang River, in terms of COD level, is going to deteriorate in the near future. Thus, the rational applications of fertilizers and pesticides in agriculture and the proper treatment of domestic sewages before they are discharged would be the most concerned controlling parameters.

Research on Drainage Network Extraction in Liaohe Basin Based on SRTM DEM and ASTER GDEM

In this study,SRTM DEM data and ASTER GDEM data were used as the basic topographic data,and Arc Hydro Tools was utilized for extension module so as to study on extracting digital drainage network of watershed based on surface runoff model,as well as to compare the two extracted results.The result showed that through the introduction of drainage density parameter to determine the river drainage area threshold,the both extracted drainages showed the goodness-of-fit with the factual drainage network on 1∶250 000 scale topographic map,and the extracted digital river could be used in practical operation of the risk assessment model of mountain torrents disaster in Liaohe basin.

A New Treatment of Depression for Drainage Network Extraction Based on DEM

Depressions in landscapes function as buffers for water and sediment. A landscape with depressions has less runoff, less erosion and more sedimentation than that without depressions. Sinks in digital elevation models （DEMs） can be considered the real features that represent depressions in actual landscapes or spurious features that result from errors in DEM creation. In many hydrological and erosion models, all sinks are considered as spurious features and, as a result, these models do not deal with the sinks that represent real depressions. Consequently, the surface runoff and erosion are overestimated due to removing the depressions. Aiming at this problem, this paper presents a new method, which deal with the sinks that represent real depressions. The drainage network is extracted without changing the original DEM. The method includes four steps： detecting pits, detecting depressions, merging depressions, and extracting drainage network. Because the elevations of grid cells are not changed, the method can also avoid producing new fiat areas, which are always produced by the conventional filling methods. The proposed method was applied to the Xihanshui River basin, the upper reach of the Jialingjiang River basin, China, to automatically extract the drainage network based on DEM. The extracted drainage network agrees well with the reality and can be used for further hydrologic analysis and erosion estimation.

How a New Cenozoic Geology and Glacial History Paradigm Explains Arkansas-Red River Drainage Divide Area Topographic Map Evidence in and near Pontotoc County, Oklahoma, USA

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.

Sediment transferring function of the lower reaches of the Yellow River influenced by drainage basin factors and human activities

Sediment transferring function (Fs) of rivers is defined and indexed in this study, based on the concept of sediment budget at river reach scales. Then, study is made on the Fs of the lower reaches of the Yellow River in relation to natural and human factors in the drainage basin, such as the annual precipitation in different water and sediment source areas, proportion of >0.05 mm sediment of the total sediment load to the lower reaches of Yellow River, the regu-lated degree of the “clear” baseflow from the drainage area above Lanzhou, frequency of hy-perconcentrated flows, area of soil and water conservation measures in the drainage basin. As a result, a multiple regression equation has been established between Fs and 7 influencing factors, with multiple correlation coefficient r = 0.90. The reduction in annual precipitation in different water and sediment source areas has different effects on Fs. The reduction in annual precipitation in the area above Hekou Town and the area between Longmen and Sanmenxia results in a reduction in Fs, but the reduction in annual pre-cipitation in the area between Hekou Town and Longmen results in an increase in Fs. The grain size composition of sediment load strongly affects the Fs; the larger the proportion of >0.05 mm sediment in the suspended sediment load entering the lower reaches of the Yellow River is, the lower the Fs will be. Thus, if the Xiaolangdi Reservoir traps coarse sediment and releases fine sediment, Fs will be enhanced. This study also shows that the lower the proportion of high-flow season river flow to the annual total river flow at Lanzhou Station is, the lower the Fs will be. Therefore, the interception of large quantities of clear water by the reservoirs on the upper reaches of Yellow River is one of the major causes for the decrease in Fs in the lower reaches of the Yellow River.

Clay minerals in surface sediments of the Pearl River drainage basin and their contribution to the South China Sea

Clay minerals have played a significant role in the study of the East Asian monsoon evolution in the South China Sea by being able to track oceanic current variations and to reveal contemporaneous pa- leoclimatic changes prevailing in continental source areas.As one of the most important rivers input- ting terrigenous matters to the northern South China Sea,the Pearl River was not previously paid at- tention to from the viewpoint of clay mineralogy.This paper presents a detailed study on clay minerals in surface sediments collected from the Pearl River drainage basin(including all three main channels, various branches,and the Lingdingyang in the estuary)by using the X-ray diffraction(XRD)method. The results indicate that the clay mineral assemblage consists dominantly of kaolinite(35%-65%), lesser abundance of chlorite(20%-35%)and illite(12%-42%),and very scare smectite occurrences (generally<5%).Their respective distribution does not present any obvious difference throughout the Pearl River drainage basin.However,downstream the Pearl River to the northern South China Sea,the clay mineral assemblage varies significantly:kaolinite decreases gradually,smectite and illite increase gradually.Additionally,illite chemistry index steps down and illite crystallinity steps up.These varia- tions indicate the contribution of major kaolinite,lesser illite and chlorite,and very scarce smectite to the northern South China Sea from the Pearl River drainage basin.The maximum contribution of clay minerals from the Pearl River is 72%to the northern margin and only 15%to the northern slope of the South China Sea.In both glacials and interglacials,kaolinite indicates that the ability of mechanical erosion occurred in the Pearl River drainage basin.

Apparent ages of suspended sediment and soil erosion of the Pearl River (Zhujiang) drainage basin

The carbon isotopic composition (Δ 14 C,δ 13 C) and apparent ages of suspended sediment were determined in the Pearl River in the years 1998,2000 and 2005.These results indicate that suspended POC consists mostly of young carbon and some "old carbon".Apparent ages of suspended POC range from 540 to 2050 a BP.The apparent ages are older in the Xijiang and Beijiang Rivers,while these values are variable in the Dongjiang River,including old and young samples.The suspended POCδ 13 C values increase with increasing Δ 14 C in the Pearl River,indicating that its source is soil and bedrock from depths under 15 30 cm.Since the organic carbon of the surface soil is quickly decomposed when it enters the rivers,its carbon isotopic characteristics are insignificant in suspended sediment.In the Pearl River drainage basin,there are areas with more severe soil erosion than others.For example,erosion is much more severe in the Xijiang River drainage basin when compared to the light soil erosion in the Dongjiang River drainage basin.

长江流域农田生态排水沟渠氮削减效应研究

为研究长江流域农田生态排水沟渠对总氮(TN)的削减效果,本研究收集长江流域生态排水沟渠的639项野外现场试验数据,通过Mann-Whitney U检验和K-W检验方法探究了不同植被类型、沟渠类型、强化措施类型、温度范围和进水浓度范围等因子对生态排水沟渠TN削减效率的影响。结果表明:在农田生态排水沟渠中,不同植被类型中的多种人工植被对TN削减效果最好,平均削减效率为47.72%;沟渠类型为边坡半衬砌(沟壁材质为部分混凝土,沟底材质为全土)对TN去除效果最佳,其平均削减率为58.18%;强化措施类型中,添加基质类和设置拦截类强化措施的生态排水沟渠对TN削减效果最好,其平均削减效率为54.24%;气温处于>25~35℃时生态排水沟渠TN削减效果更有效,而在低温环境下可以通过种植耐寒植物(绿狐尾藻、黑麦草等)提高削减率;沟渠进口TN浓度多数集中在>2~4 mg·L^(-1)之间,沟渠出口TN浓度主要分布在0~2 mg·L^(-1)之间,TN进口浓度为>2~4 mg·L^(-1)时沟渠TN削减效果最佳;不同浓度条件下,沟渠选择种植多种人工植被,对沟壁进行半衬砌,设有强化措施都能有效提高TN的净化效果;TN削减效率与水力停留时间、沟渠长度、水深呈现正相关;在多种因素最优的情形下,TN表面去除负荷随着TN进口浓度增大而增大。研究表明,长江流域农田生态排水沟渠选择多种人工挑选的植被、沟渠类型选择边坡半衬砌、同时添加基质类和设置拦截类强化措施更能有效地削减TN,并且控制气温在>25~35℃和进口浓度为>2~4 mg·L^(-1)来削减TN,另外延长沟渠长度和控制水体的水深、水力停留时间可更好地削减TN。

基于补偿水头差的沿江口门引排流量计算方法研究

长江支流口门多建有节制闸,利用涨落潮过程自行引排水,而引排水流态的复杂性使得引排流量过程难以精准确定。以太湖流域杨林塘口门为例,通过分析引排水调度方式及流态特征,发现涨潮时开启中孔闸门引水,内河侧流态复杂且附近水位差别大,而落潮时开启全部闸门排水,外江侧流态复杂且附近水位有所差别。为此,提出了一种基于补偿水头差的沿江口门引排流量计算方法。该方法通过设置系列补偿水头差修正堰流公式中的水位,统计了计算流量与实测流量偏差值,进而建立了流量偏差值与补偿水头差的相关关系,最终确定适宜的补偿水头差,从而建立适宜沿江口门引排流量计算公式。结果表明:利用该方法预测的引水流量误差减小40%~50%,排水流量误差减小3%~6%。相关经验可供工程设计人员及闸管单位运行管理人员借鉴。

基于城市排水过程的内涝高效模拟方法

从实际城市排水过程的角度出发,提出了基于汇水单元概念的城市内涝高效模拟方法.该方法以雨篦子作为出水口来划分汇水单元,进而计算城市地表产汇流、积水深度及分布.同时,引入了当量宽度的概念,实现了明渠与有压流2种状态下管道流量和水位计算方法的统一.基于水量平衡原理,利用雨篦子耦合城市地表与地下管网,并结合孔口耦合管道与河道,构建了地表-管道-河道一体化的求解矩阵.本文将所提出的模拟方法植入成熟的太湖流域模型,并应用常州市城市产汇流与内涝试验基地的监测数据,对该方法的有效性和模型的可靠性进行了评估,以期为城市内涝模拟提供新思路.

中国台湾岛流域地貌对构造活动的响应

基于SRTM DEM 30m数据和ArcGIS软件,提取台湾岛的水系和流域盆地,计算得到台湾岛的地貌参数(坡度、地形起伏度和面积-高程积分(HI)值),并分析台湾岛水系分布对活动断裂的响应情况,得到以下结论:1)台湾岛河流受构造活动控制,以中央山脉为分水岭,西侧河流的南部水系为纵向流动,北部水系为横向流动,中央山脉以东的河流均为东西流向;2)台湾岛的HI值整体上呈现中间高、两边低的趋势,与海拔大体上呈正相关关系,沿逆冲断层边界,不同构造地质单元的HI值东西两侧差异明显;3)HI值可以反映台湾岛造山带的生成时序,流域盆地受构造抬升运动影响时间越长,HI值越大。

沙田镇西太隆河流域综合整治工程设计方案研究

东莞市经济快速发展的同时,西太隆河流域内水环境建设滞后。为改善流域内生态环境,亟需实施流域综合整治工程,工程主要分为水安全、水环境、水景观和智慧水务4个部分。水安全方面因地制宜建设复合型生态护岸;水环境方面对淤积河道进行清淤疏浚;水景观方面通过打造节点景观和万里碧道来构建生态廊道;智慧水务方面着力构建流域立体水务信息采集系统。通过对不同子项工程的治理措施及设计方案进行研究,工程实践表明,项目的实施可有效改善流域环境,促进宜居水岸打造。

高质量发展背景下黄河流域主要城市供排水特征及问题解析

围绕黄河流域城镇供、排水处理行业家底不清的实际问题,为应对黄河流域高质量发展的实际需求,通过构建指标体系、收集基础数据、归纳与总结,系统分析黄河流域供、排水特征。结果表明:2017-2021年,黄河流域用水人口呈缓慢上升的趋势,年平均增长率为3.80%,流域供水压力大;截至2021年底,黄河流域各省区公共供水总漏损水量共计5.90亿m^(3),共有41座城市漏损水量与公共供水总量比值高于9%,城市公共管网漏损水量高;2022年,黄河流域各省区城市生活污水集中收集率平均值为71.8%。其中,四川省和青海省的城市生活污水集中收集率分别为64.2%和53.9%,流域内城市生活污水集中收集率水平不一。建议流域各地区政府应高度重视提高水资源利用效率,拓展再生水利用领域和规模,同时应全面加强城市供水管道的智能监管,进一步降低管网漏损,以缓解流域供水压力。对于城市生活污水集中收集率低的城市应加强污水处理设施建设规划、合理推进雨污分流改造工程、注重污水收集管网的检测和维护,鼓励有条件的城市开展“清水”入流污水管网的影响以及清退的可行性研究,为提升污水处理系统运行能效提供基础保障。

元代黑龙江流域农业经济研究

元初,黑龙江流域饱受战乱之苦,社会经济凋敝。平息乃颜、哈丹之乱后,元廷着手恢复农业生产:派遣汉族官兵至上游怯绿连河(今克鲁伦河)和混同江(今松花江)一带,与当地女真族和蒙古族人民一道屯田,建立浦峪路屯田万户府、肇州蒙古屯田万户府、水达达屯田总管府;将“流囚”从奴儿干改发至肇州屯田;上百户张成等率部屯田于水达达地面以至于“黑龙江之东北极边”地区楚科奇半岛;每有灾荒,元廷要赈济受灾农户。这些举措使得黑龙江流域的农业生产得到了有效恢复和发展,促进了社会经济的进步。