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所在平台: Udemy |
课程主页: https://www.udemy.com/course/learn-hydrology-from-the-scratch/
课程评论：没有评论
课程名称：从零开始学习水文学 课程概述： 本课程旨在让学生深入了解水文学的基本概念。课程主要内容包括孔隙率、渗透性、盐水入侵等基础知识，以及水文图和其类型的应用。水文图是一种展示特定地点或横截面水流速率与时间关系的图表，通常用于评估开发项目特定地点的暴雨径流情况。 在自然景观中，由于植被和土壤的渗透能力，雨水抽取水平高、径流较少，形成逐渐上升的水文图。而当自然景观被开发后，树木和植被被不透水表面（如屋顶、车道、排水沟和停车场等）取代，导致景观过滤和渗透水的能力下降，从而在水文图中显示出更高的峰流量和更多的径流量。失去自然管理暴雨水的重要性，导致土壤侵蚀、沉积和营养物质流入水道。 那么，如何防止这种情况发生呢？低影响开发（LID）是一种旨在模仿原有场地水文特征的设计策略，采用多种最佳管理实践（BMP）进行实施。如果场地规划者了解开发前的水文图，他们能够调整场地规划，采用诸如雨水花园和生物沟等方法来应对现场的径流，从而形成新的水文图。 对于已经建成的房屋，LID同样适用于重新开发或改造的应用。对于以前开发的场地，最佳管理实践可以在现有条件内进行安装。例如，通过断开雨水下水道并将径流引导到草坪或花园中，能够有效改善场地的水文图，减少污染物进入当地溪流的可能性。 水文图是反映水文变量随时间变化的图表，课程还将提供美国地质调查局在宾夕法尼亚州Tioga河附近的监测站的数据作为实例。影响洪水水文图动态的物理因素包括：流域形状、地形与起伏、大雨、持续降雨、植被类型以及岩土种类等。 通过本课程，学生将系统掌握水文学的基本概念及其在环境管理中的应用，帮助他们在未来的开发和再开发项目中做出更为科学的决策。
Students will learn about Hydrology. Porosity, Permeabilty, Salt Water Intrusin along with Hydrographs & types: A hydrograph is a graph or plot that shows the rate of water flow in relation to time, given a specific point or cross-section. These graphs are often used to evaluate stormwater runoff on a particular site considering a development project.A natural landscape with no development or impervious surfaces will have high levels of rainfall abstraction and produce less runoff due to the vegetation and infiltration capacity of the soils, which produces a gradually sloped hydrograph (1). In this scenario, rainwater will meet multiple obstacles while flowing towards a stream in the form of rainfall interception by vegetation,transpiration by plants, evaporation from land surfaces, infiltration into soils, and ponding of water in surface depressions.When the natural landscape is altered by development, trees and other vegetation are replaced by impervious surfaces such as roofs, driveways, gutters, and parking lots. These impervious areas curtail the landscape'sability to filter and infiltrate water, and results in higher peak flows and greater runoff volumes as seen inhydrograph (2). Stripping the landscape's ability tonaturally manage stormwater results in increasederosion, sedimentation, and nutrientsentering our waterways.So how can we prevent this from happening? LowImpact Development (LID) is a design strategy that strives to mimic the pre-existing site hydrology using a variety of best management practices (BMPs). If a site planner knows what the hydrograph for a site lookedlike prior to development, they can amend their site plan to accommodate increased runoff onsite using practices such as rain gardens and bio-swales. This will produce a hydrograph (3).What if my home is already built? LID can be used in redevelopment or retrofitapplications as well. Forpreviously developed sites, best management practices can beinstalled within the confines ofexisting site conditions. Simple practices, such asdisconnecting a downspout and redirecting runoff into a lawn or garden, will have positive impacts on a site's hydrograph and help prevent pollutants from entering your local stream. Stream discharge hydrograph..Hydrographs are charts that display the change of a hydrologic variable over time. Here are several examples from the US Geological Survey's gaging station on the Tioga River near Mansfield, Pennsylvania. Physical factors affecting flood hydrograph dynamicsShape. A circular-shaped drainage basin leads to rapid drainage whereas a long drainage basin will take time for the water to reach the river.Topography & relief.Heavy Storms.Lengthy rainfall.Snowfall.Vegetation.Rock type.Comparing hydrographsSteep Slopes.Deciduous trees.An urban area in its catchment.Clay soils that stop water soaking in.Permeable ground.Heavy sudden precipitation.Long periods of steady rainfall.Lots of streams gathering water in the basin.
