The City of Takoma Park, Maryland, needed to replace a failing retaining wall that supports a roadway in a small residential development. The Linden Avenue site is directly adjacent to Sligo Creek, which is a tributary of Anacostia Creek, a river undergoing a significant restoration effort. T. E. Scott & Associates, Inc., designed a replacement for the failing retaining wall infrastructure, created a pocket park for the local residents, and provided water quality treatment for the unmanaged watershed. This combination of aesthetic and environmental improvements adds value to the project. We’ll look at some stormwater flow design calculations, a storm water flow splitter, an urban modular wetland unit, a step/plunge pool, and an interesting retaining wall design.
The American Society of Civil Engineers (ASCE) includes Levees on its 2009 Report Card for America's Infrastructure, giving them a D–. The category of "Levees" covers major flood control works. However, what about the water that causes the flooding that levees protect against? Throughout drainage basins comprising thousands of square miles, stormwater runoff makes its way downstream. Obviously some systems convey that stormwater and even control it. ASCE says nothing about these storm sewer systems, but they form a vital part of America's infrastructure.
土木工程师设计它们，景观设计师勉强他们，开发商想知道为什么我们需要他们和市政工程师往往需要他们 - 我恨他们。保留和拘留池塘已经成为雨水管理标准在整个美国大部分的商业和住宅项目。他们原本打算用于防洪，后来并入水质的要求也是如此。他们服务于他们的能力减弱峰新开发流还算不错，但其效用停在那里。这里有几个原因，我不是拘留/储水池的粉丝：
Rainwater can be harvested with large, sophisticated, complex systems, linked rain barrels, or a single rain barrel. A single rain barrel is typically installed under a downspout as a repository for the rainwater collected by the roof gutters. 藏用于存储的可用淡水供应。它们通常通过在现有的盆地筑坝天然地表水支流创建的，但它们可以被人工构造为好。 Water stored in reservoirs can have various functions, including serving as a source of potable water, irrigation, recreation and hydroelectric power. Reservoirs are designed and evaluated based on their storage capacity, which is commonly measured in acre-feet. Changes in reservoir storage capacity over a given time period are defined by an assessment of inputs and outputs. Inputs include tributary inflow, precipitation, and water from groundwater flow nets. Outputs are made up of draw-downs for irrigation and potable water, regulated flow to release excess storage or provide turbine power, and losses due to evaporation and seepage. Reservoir (and pond) covers and liners are sometimes used on a smaller scale project to prevent losses from surface evaporation and seepage into the containment basin. Subsurface water stored in soils as groundwater or in aquifers is a variation of the reservoir concept. 
降雨不透的表面，如铺路和屋顶结构将导致雨水径流。 Successive site improvements will trigger a requirement for an engineered system to thoughtfully manage storm water run-off. In improved locations such as new suburban subdivisions, the amount of run-off is significantly increased compared to that of the previously undeveloped acreage. Storm water management is achieved through storm drainage utilities, which are comprised of a physical network of site grading, curbs, culverts, catch basins, piping, manholes and, sometimes, retention or detention ponds. Another aspect of storm water management is government regulation, which may impose water quality discharge standards and limits on how much site improvement can be authorized at sensitive project locations.