径流曲线法在黄土区小流域地表径流预测中的初步应用

径流曲线法是目前国际上预测无径流观测资料地区降水地表产流的主要模型,由于气候、水文及下垫面的差异,在黄土高原地区的应用受到限制。利用黄土高原地区3个小流域的303场降雨径流资料,针对黄土高原降雨地表径流特点优化模型中的初损率λ,并提出降雨强度修正函数,将降雨强度因子引入径流曲线法。优化后的模型效率E达到0.812,实测径流深与预测径流深的线性回归决定系数R2达到0.822。改进后的SCS-CN模型可用于黄土区小流域降雨地表产流预报,对黄土高原无资料地区侵蚀产流预报、指导水土保持工程配置和设计具有重要的理论和工程实践意义。

景观格局对土壤侵蚀的影响研究-以岷江上游的小流域为例

岷江上游地区生态环境脆弱，加之不合理的土地利用，土壤侵蚀问题日趋严重。准确定量土壤侵蚀、产沙模数的空间分布，从而分析土地利用及其空间配置对于土壤侵蚀过程是否合理？对减少长江上游的输沙量具有重要意义，是一个严峻的研究课题。本文以GIS为平台，建立泥沙输移分布模型，模拟流域的侵蚀模数、泥沙输移比和产沙模数的空间分布；结合模型模拟结果，分析不同土地利用/覆被方式的侵蚀和产沙特征，并以景观生态学的“格局-过程”理论为基础，通过景观指数——景观空间负荷对比指数，探讨土地利用/覆被的空间格局对土壤侵蚀过程的影响。泥沙输移分布模型模拟的产沙量与实测值比较，结果十分理想。模拟结果表明：两个流域大部分区域属于微度到中度侵蚀，平均侵蚀模数略低于长江上游的平均值；两个流域的平均泥沙输移比均远小于长江上游的平均值；河流两侧1 km范围内是流域主要的产沙区域；不同土地利用/覆被方式的侵蚀模数不同——裸岩>居民点>草地 >农田>灌木林>林地；侵蚀广泛分布在草地、林地和灌木林地上，占流域侵蚀总量的80%以上；灌木林和林地是流域主要的产沙源，占总产沙量的60%以上。景观空间负荷对比指数的计算结果表明：两个流域土地利用/覆被随坡度的空间配置有利于水土保持，但随相对距离、相对高度和运移距离的空间配置不利于水土保持；两个流域“源”大“汇”小的土地利用/覆被组成方式有利于水土保持，且镇江关流域的组成方式更优；景观空间负荷对比指数能够比较全面客观地反映景观格局对对土壤侵蚀过程的影响：两个流域的景观格局均较为合理；且镇江关流域的景观格局优于黑水流域。

潮滦河小流域鱼鳞坑内外植被群落特征与环境关系

通过对小流域不同坡面上鱼鳞坑的内外群落植被调查,研究了该地区鱼鳞坑内外植被群落特征与海拔及坡向的关系。(1)阴坡鱼鳞坑内的盖度大于阳坡鱼鳞坑内的盖度,并且达到极显著水平。(2)坡向不是控制该区域植被群落多样性的主导因子。(3)不同土地类型鱼鳞坑外的群落丰富度指数,Shannon- Wiener指数及同一土地类型的鱼鳞坑内外群落的指数均与海拔高度成极显著的抛物线函数关系,但是与鱼鳞坑内群落的多样性指数不成显著相关关系。结果显示,可以通过像鱼鳞坑这样的整地方式来改变小生境以促进群落植被的物种多样性。

黄土沟壑区小流域水土保持减水效益分析

在实测资料的基础上借助流域水沙耦合模型中的产流模式 ,将水土保持减水型措施和植被型措施在减流中的作用定量分割开来 ,为区域水土流失综合治理提供基础数据 .结果显示 ,高度综合治理的插财主沟和杨家沟小流域平均减水分别为 6 6 .2 %和 5 8.7% .其中减水型措施分别减水 42 .0 %和 19.8% ,植被型措施分别为 2 4.2 %和 38.9% .与未治理小流域相比 ,综合治理使小流域拦蓄水程度明显提高 ,减水型措施拦蓄径流作用显著高于植被型措施

黄土高原水土保持的水文环境效应研究进展

黄土区大面积、高强度的植被营造工程和各项水利工程虽充分利用了有限的水资源 ,减少了入黄泥沙 ,但同时也人为的切断或改变了水分循环的途径 ,对水环境产生不同方向和程度的影响。尽管国内外学者对水土保持的水环境效应已进行了不少研究 ,但仍存在一些问题 ,主要表现在单项措施 ,特别是林草措施下的水环境效应研究比较深入 ;在水环境研究内容上 ,多注重对地表径流减水减沙的分析 ,而对水量平衡、水文情势等研究较少 ;在研究尺度上 ,多集中于对径流小区的分析 ,单点研究深入而面研究不够

黄土丘陵沟壑区山坡道路防蚀措施初步研究

山坡道路连接农田、果园 ,对山区经济发展有重要作用。黄土高原山坡道路存在严重的水土流失 ,侵蚀方式主要有沟蚀、泻溜、崩塌、陷穴、悬沟侵蚀与滑坡等。山坡道路网应按照小流域综合治理规划合理布置 ,其主要防护措施 :①修筑梯田 ,防止坡面径流冲刷道路 ;②将路面整修成拱形以分散径流 ;③在道路内侧修蓄水窑窖 ,拦蓄径流 ;④路面及边坡栽植草灌 ,防止雨水冲刷

黄土高原降雨空间分布的不均匀性研究

根据黄土高原13条流域的降雨资料，分三种雨型即局地强对流条件引起的小范围、短历时、高强度的局地性暴雨（A型暴雨），峰面型降雨夹有局地雷暴性质的较大范围、中历时、中强度暴雨（B型暴雨），峰面型降雨引起的大面积、长历时、低强度暴雨（C型暴雨）；选用流域面雨量离差系数Cv、流域降雨不均匀系数η和流域最大点与最小点降雨量比值系数α三种指标，分析了次降雨空间分布的不均匀性。

Model analysis of dissolved inorganic phosphorus exports from the Yangtze river to the estuary

In this paper, we estimate the inputs of phosphorus (P) to the Yangtze River Basin and exports of dissolved inorganic phosphorus (DIP) from the river to the estuary for the period 1970-2003, by using the global NEWS-DIP model. Modeled DIP yields range from 2.5 kg P km(-2) yr(-1) in 1970 to 4.6 kg P km(-2) yr(-1) in 1985, and then dramatically increase to 14.1 kg P km(-2) yr(-1) in 2003. No significant difference between the modeled and measured values at the level of P = 0.05 is observed. The study also demonstrates variable source contributions of P to the modeled DIP during the period 1970-2003. Point sewage P input accounted for approximately 100% in the period 1970-1985 and substantially decreased to 24.8% in 2003. Chemical fertilizer contributed 25.4% of DIP yields in 1986 and increased continuously to 50.3% in 2003, while a stable trend in manure P contribution averaging 22.9% of DIP yields was shown in the same period. The study concludes that P inputs to the Yangtze River Basin and the river DIP export to the estuary have substantially increased during the study period consequence to human pressure.

Levantamento semidetalhado dos solos da bacia Rio Jardim-DF escala 1:50.000.

2000

Levantamento semidetalhado dos solos da bacia do Olaria - DF escala 1:30.000.

2000

Caracterização dos solos da microbacia do Ribeirão Barro Branco, município de São José de Ubá - RJ.

O presente estudo refere-se à caracterização dos solos da microbacia do ribeirão Barro Branco no município de São José de Ubá, Rio de Janeiro, abrangendo uma área de cerca de 550 ha, como parte integrante do Projeto Modelagem Hidrológica apoiado pela FAPERJ. O resultado final deste estudo consistiu no Mapa Semidetalhado de Solos da microbacia de acordo com as normas preconizadas pela Embrapa Solos, com a utilização de geotecnologias e técnicas de mapeamento digital. Consiste na caracterização dos solos visando contribuir para o planejamento do uso e ocupação das terras de forma racional e sustentável. Como material básico, utilizou-se uma aerorrestituição na escala 1:10.000 que foi empregada para a geração de um modelo digital de elevação (MDE), tendo ainda o apoio de imagens do Sensor Geoeye-1 de 2010. Os resultados obtidos, além de permitirem uma visão geral sobre as características ambientais da área, contêm todos os critérios utilizados para distinção e classificação dos solos e uma descrição das principais classes de solos da área estudada, cuja distribuição espacial é representada em um mapa na escala 1:10.000. Este mapa é constituído por 25 unidades de mapeamento, que compõem uma legenda de identificação dos solos, individualizados até o 5º nível categórico do Sistema Brasileiro de Classificação de Solos (SiBCS), seguido de textura, tipo de horizonte A, fases de vegetação, relevo e, para solos pouco evoluídos, substrato geológico. As principais classes de solos identificadas foram: Argissolos Vermelhos; Argissolos Vermelho-Amarelos; Gleissolos, Argissolos Amarelos; Afloramentos de Rocha e Luvissolos. Os primeiros apresentando grande predomínio sobre as demais classes da área com ocorrência superior a 42% do total. O principal tipo de utilização agrícola nessa microbacia é com pastagens, em sua maioria em estágio avançado de degradação, devido à baixa capacidade de retenção de água no solo, a baixa fertilidade e o baixo nível de utilização de insumos e práticas de conservação de solos na área.

Vulnerability and adaptation to climate change in Guam – a case-study of the perceptions, attitudes, behaviors, and knowledge of a small rural community towards their watershed

This thesis argues that examining the attitudes, perceptions, behaviors, and knowledge of a community towards their specific watershed can reveal their social vulnerability to climate change. Understanding and incorporating these elements of the human dimension in coastal zone management will lead to efficient and effective strategies that safeguard the natural resources for the benefit of the community. By having healthy natural resources, ecological and community resilience to climate change will increase, thus decreasing vulnerability. In the Pacific Ocean, climate and SLR are strongly modulated by the El Niño Southern Oscillation. SLR is three times the global average in the Western Pacific Ocean (Merrifield and Maltrud 2011; Merrifield 2011). Changes in annual rainfall in the Western North Pacific sub‐region from 1950-2010 show that islands in the east are getting much less than in the past, while the islands in the west are getting slightly more rainfall (Keener et al. 2013). For Guam, a small island owned by the United States and located in the Western Pacific Ocean, these factors mean that SLR is higher than any other place in the world and will most likely see increased precipitation. Knowing this, the social vulnerability may be examined. Thus, a case-study of the community residing in the Manell and Geus watersheds was conducted on the island of Guam. Measuring their perceptions, attitudes, knowledge, and behaviors should bring to light their vulnerability to climate change. In order to accomplish this, a household survey was administered from July through August 2010. Approximately 350 surveys were analysed using SPSS. To supplement this quantitative data, informal interviews were conducted with the elders of the community to glean traditional ecological knowledge about perceived climate change. A GIS analysis was conducted to understand the physical geography of the Manell and Geus watersheds. This information about the human dimension is valuable to CZM managers. It may be incorporated into strategic watershed plans, to better administer the natural resources within the coastal zone. The research conducted in this thesis is the basis of a recent watershed management plan for the Guam Coastal Management Program (see King 2014).

The toxicology of climate change: environmental contaminants in a warming world.

Climate change induced by anthropogenic warming of the earth's atmosphere is a daunting problem. This review examines one of the consequences of climate change that has only recently attracted attention: namely, the effects of climate change on the environmental distribution and toxicity of chemical pollutants. A review was undertaken of the scientific literature (original research articles, reviews, government and intergovernmental reports) focusing on the interactions of toxicants with the environmental parameters, temperature, precipitation, and salinity, as altered by climate change. Three broad classes of chemical toxicants of global significance were the focus: air pollutants, persistent organic pollutants (POPs), including some organochlorine pesticides, and other classes of pesticides. Generally, increases in temperature will enhance the toxicity of contaminants and increase concentrations of tropospheric ozone regionally, but will also likely increase rates of chemical degradation. While further research is needed, climate change coupled with air pollutant exposures may have potentially serious adverse consequences for human health in urban and polluted regions. Climate change producing alterations in: food webs, lipid dynamics, ice and snow melt, and organic carbon cycling could result in increased POP levels in water, soil, and biota. There is also compelling evidence that increasing temperatures could be deleterious to pollutant-exposed wildlife. For example, elevated water temperatures may alter the biotransformation of contaminants to more bioactive metabolites and impair homeostasis. The complex interactions between climate change and pollutants may be particularly problematic for species living at the edge of their physiological tolerance range where acclimation capacity may be limited. In addition to temperature increases, regional precipitation patterns are projected to be altered with climate change. Regions subject to decreases in precipitation may experience enhanced volatilization of POPs and pesticides to the atmosphere. Reduced precipitation will also increase air pollution in urbanized regions resulting in negative health effects, which may be exacerbated by temperature increases. Regions subject to increased precipitation will have lower levels of air pollution, but will likely experience enhanced surface deposition of airborne POPs and increased run-off of pesticides. Moreover, increases in the intensity and frequency of storm events linked to climate change could lead to more severe episodes of chemical contamination of water bodies and surrounding watersheds. Changes in salinity may affect aquatic organisms as an independent stressor as well as by altering the bioavailability and in some instances increasing the toxicity of chemicals. A paramount issue will be to identify species and populations especially vulnerable to climate-pollutant interactions, in the context of the many other physical, chemical, and biological stressors that will be altered with climate change. Moreover, it will be important to predict tipping points that might trigger or accelerate synergistic interactions between climate change and contaminant exposures.

Isotopic imprints of mountaintop mining contaminants.

Mountaintop mining (MTM) is the primary procedure for surface coal exploration within the central Appalachian region of the eastern United States, and it is known to contaminate streams in local watersheds. In this study, we measured the chemical and isotopic compositions of water samples from MTM-impacted tributaries and streams in the Mud River watershed in West Virginia. We systematically document the isotopic compositions of three major constituents: sulfur isotopes in sulfate (δ(34)SSO4), carbon isotopes in dissolved inorganic carbon (δ(13)CDIC), and strontium isotopes ((87)Sr/(86)Sr). The data show that δ(34)SSO4, δ(13)CDIC, Sr/Ca, and (87)Sr/(86)Sr measured in saline- and selenium-rich MTM impacted tributaries are distinguishable from those of the surface water upstream of mining impacts. These tracers can therefore be used to delineate and quantify the impact of MTM in watersheds. High Sr/Ca and low (87)Sr/(86)Sr characterize tributaries that originated from active MTM areas, while tributaries from reclaimed MTM areas had low Sr/Ca and high (87)Sr/(86)Sr. Leaching experiments of rocks from the watershed show that pyrite oxidation and carbonate dissolution control the solute chemistry with distinct (87)Sr/(86)Sr ratios characterizing different rock sources. We propose that MTM operations that access the deeper Kanawha Formation generate residual mined rocks in valley fills from which effluents with distinctive (87)Sr/(86)Sr and Sr/Ca imprints affect the quality of the Appalachian watersheds.

Morphological characteristics of urban water bodies: mechanisms of change and implications for ecosystem function.

The size, shape, and connectivity of water bodies (lakes, ponds, and wetlands) can have important effects on ecological communities and ecosystem processes, but how these characteristics are influenced by land use and land cover change over broad spatial scales is not known. Intensive alteration of water bodies during urban development, including construction, burial, drainage, and reshaping, may select for certain morphometric characteristics and influence the types of water bodies present in cities. We used a database of over one million water bodies in 100 cities across the conterminous United States to compare the size distributions, connectivity (as intersection with surface flow lines), and shape (as measured by shoreline development factor) of water bodies in different land cover classes. Water bodies in all urban land covers were dominated by lakes and ponds, while reservoirs and wetlands comprised only a small fraction of the sample. In urban land covers, as compared to surrounding undeveloped land, water body size distributions converged on moderate sizes, shapes toward less tortuous shorelines, and the number and area of water bodies that intersected surface flow lines (i.e., streams and rivers) decreased. Potential mechanisms responsible for changing the characteristics of urban water bodies include: preferential removal, physical reshaping or addition of water bodies, and selection of locations for development. The relative contributions of each mechanism likely change as cities grow. The larger size and reduced surface connectivity of urban water bodies may affect the role of internal dynamics and sensitivity to catchment processes. More broadly, these results illustrate the complex nature of urban watersheds and highlight the need to develop a conceptual framework for urban water bodies.