水韵发表：人工湖用于雨水管理_【水韵水环境设计】

ManmadeLakesforStormwaterManagement人工湖用于雨水管理Aquas...

Manmade Lakes for Stormwater Management

人工湖用于雨水管理

Aquascape facilities have traditionallybeen considered ornamental and landscape features, primarily serving aestheticpurposes in golf courses, parks and residential developments. However, aquascapes can be applied withinnovative design elements to function as primary infrastructure facilities inurban developments, replacing typical stormwater facilities and adding value tocommunities.   These specialized types ofaquascape systems integrate a living ecosystem into an urban environment, whichmaintains water quality through natural biological processes.

水景设施传统上一直被认为具备观赏性，隶属于景观设施的范畴，主要用于为高尔夫球场、公园及住宅开发项目营造景观效果。但是，水景中也可融入创新的设计元素，使其在城市发展中发挥基础设施的功能，进而取代常规的雨水设施，提升社区价值。这些特殊的水景系统可以将自然生态系统融入城市环境之中，利用自然生物过程维持水体水质。

Planned aquascape features, particularly insemi-arid areas, offer a combination of many unique advantages for stormwatermanagement as well as other benefits that are not available in conventionalengineered systems, including: (1) continuous year-round natural treatmentprocess, (2) stormwater conveyance and storage, (3) enhanced water qualitytreatment, (4) flood protection, (5) combined land use elements, (6)significantly reduced infrastructure costs, (7) dry weather flow treatment, (8)landscape and aesthetic treatment with natural water system, (9) increasedsurrounding land values, (10) natural ecosystem benefits, (11) recreationaldesign feature, and (12) urban design element for communities.

经过设计的水景设施，尤其是在半干旱地区，具备多种独特的优势，不但可以融入雨水管理功能，还具备多种传统工程系统没有的好处，包括：（1）全年持续不间断地进行自然化的处理（2 ）运送和储存雨水（3）改善水质处理效果（4）防洪（5）整合用地规划（6）显著降低基础设施成本（7）处理干燥气候条件的地表径流（8）作为景观设施的同时利用自然系统实现净化处理（9）提升周边土地价值 (10）建立自然生态系统（11）具备休闲娱乐的特点（12）为社区创造城市设计元素。

The necessity for stormwater pollutioncontrol has received increased public attention, especially with the escalatingenvironmental regulations focusing on non-point source pollution and protectionof receiving waters.   Traditionalmethods generally have limited pollutant removal effectiveness; perform singlefunctions; require considerable land; have numerous maintenance issues/constructioncosts; have difficulty integrating with the land plan; and are typicallyunsightly having limited aesthetic appeal to the community. Integrating largescale specialty aquascape systems through constructed lakes, ponds, smallcreeks, or other water features can replace traditional underground drainage infrastructureand provide highly effective stormwater treatment. The result is high waterquality not available through other conventional methods.

对于雨水污染控制的必要性越来越受到公众的关注，特别是关于非点源污染控制和受纳水体的保护的多项环境法规的出台。传统控制方法一般具有诸多问题，包括污染去除效果差、功能单一、占地面积广、维修问题多、施工成本高、与用地规划整合难以及无法为社区营造美丽景观等。但是利用湖泊、水塘、小溪或其他水景等形成的水景设施可以取代传统的地下排水设施，并提供高效的雨水处理功能，其效果是保持高水质的水体，这是传统方法无法实现的。

Standard Aquascape Water Quality Design Requirements

标准水景设施水质设计要求

There are specific design issues andrequirements commonly associated with any aquascape feature in order tomaintain a minimum operational quality of a water body. Critical issues involved in the design of anyaquascape feature include the ability to maintain long-term water quality,which generally focuses on algae control, nutrients, alkalinity, andtemperature. All water bodies willexperience the natural eutrophication process related to the depletion of theavailable supply of dissolved oxygen from increased nutrients and minerals. This can negatively result in changes to thecharacteristics that include algae blooms, scum formation, transparency, andodors. Water features will alsoexperience daily evaporation which increases the long-term alkalinity ordissolved salts in the water. Conventional aquascape system designs attempt to eliminate or prevent stormwaterrunoff inflow in an attempt to minimize nutrient input for algae control. A technique that is employed to minimizeeutrophic conditions is to allow water exchange or flushing of the lake tolimit nutrient concentrations. Manmadelake systems for parks and golf courses commonly serve a dual function as anirrigation storage reservoir and this stored water will be withdrawn from theaquascape for irrigation use, indirectly resulting in flushing of thesystem. Irrigation lakes allow for ahigh turnover or replacement of the water volume and multiple lakes can beinterconnected to achieve the maximum benefits. Correctly locating the inlet and outlet at opposite ends of a water bodyand with the direction of the wind will assist in achieving plug flow tomaximize horizontal circulation benefits.

任何水景设施的设计都涉及许多具体的设计问题和要求，其关键问题包括是否具备保持水质长期良好的能力，，这一般主要着眼于控制藻类、营养盐、碱度和温度。所有水体都会经历富营养化的自然过程，这是由于养分和矿物质增加造成溶解氧供应量出现枯竭所致，所带来的消极结果是藻类大量繁殖、形成浮渣、透明度降低以及出现异味等。同样水景每天也会蒸发，长期以来会造成水中碱度或溶解盐浓度升高。传统的水景设计试图隔绝或者控制雨水地表径流进入水体，以尽量减少养分的输入，从而控制藻类的生长。一个可用来削弱富营养化条件的技术是实现湖体换水或冲洗来限制养分的浓度。公园和高尔夫球场内的人工湖泊除了作为景观设施之外，还具备储蓄灌溉用水的功能，这些蓄积的水可用在需要时被抽走用于灌溉，因此间接形成了对湖泊系统的冲洗。湖泊用于提供灌溉用水后可用获得较高的换水频率或实现湖水的全部置换，同时为了使益处更大化，还可用将多个湖体连通。正确确定湖泊两端的进出水口以及风向可共同作用帮助实现湖体水平向的循环。

Improving low dissolved oxygen in manmadewater features is typically achieved through aeration, either through a bubbleror spray system, and also the natural wind action on the surface. Spray systems generally require morehorsepower to operate or increased long-term costs without any additionaladvantages except for the visual benefits of a fountain-like system. Bubblers or a fine bubble diffusion systemplaced along the bottom of the water feature will induce vertical recirculationwithin the lake itself that results in destratification and reduction of thesurface water temperature, avoiding conditions leading to undesirable algaeblooms.

在人工湖泊中提高溶解氧浓度通常都是通过曝气系统以及水面的自然风作用来实现的。曝气系统有两种，一种是曝气盘，另一种是喷水装置。喷水装置需要较大的电力而且长期运营成本比较高，除了看似喷泉之外其优势并不大，然而设置在湖底底部的微孔曝气盘可以实现湖体的垂直循环，减少水体分层，同时降低水面温度，避免不利条件出现导致藻类大量繁殖。

Another critical aspect of a water featurethat affects operating characteristics and water quality is the horizontallayout and geometry. Constructed lakeswithin residential developments are commonly developed with a layout tomaximize the amount of lake water front homes through a layout incorporatingnumerous “fingers”. However, a layoutwith fingers will develop circulation dead zones, poor water quality, andgenerally require a more extensive plumbing infrastructure and pumping tooffset circulation issues.   A “snake”type layout is preferred since it will provide the same maximum edge frontageas a finger system, but have the benefit of improved circulation since plugflow can now be developed in this system. The other important characteristic of the geometry influencing lakequality is the normal operating water depth since this determines the effectsof temperature and biological reaction time increases with temperature. A minimum operating depth of eight to twelvefeet will eliminate light penetration, maintain lower average temperature,allow temperature stratification, and minimize evaporation.

影响水景运行和水质的另外一个关键因素是横向布局和几何形状。住宅开发项目上的人工湖泊通常情况为了最大程度上增加亲水住宅的数量而形成一个拥有多个“手指”状狭窄水域的湖泊布局。然而，这种布局会出现循环死区，造成水质变差，同时还需要增加更多的管道和水泵来弥补循环不够问题。“蛇”型布局则相比而言更好，因为它不仅可用提供与“手指”布局相同的亲水面积，还可以改善水体循环效果。其他影响湖泊水质的几何因素是正常运行情况下湖泊的水深，因为它直接决定着湖水温度以及生物活性反应时间。最低8-12英尺的水深可用有效减少透光量，保持较低的平均温度，同时实现温度分层，减少蒸发。

Integrating Stormwater Treatment

融合雨水处理

Providing the stormwater treatment functionas part of an aquascape relies on recreating a natural ecosystem that canutilize biologic processes for treatment of urban pollutants in runoff as wellas maintaining the normal health of the aquascape system. The primary elements that have beenintegrated into this unique type of aquascape treatment system include: (1)wetlands planters, (2) lake biofilter beds, (3) pretreatment wetland filters,(4) aeration, and (5) stormwater retention volume/capacity, when successfullyapplied can achieve exceptional water quality results. Pretreatment of the stormwater is a criticalelement to enhancing the overall performance and should be performed for allinflows into the aquascape in order trap larger sediments. Wetland filters or vegetated “first flush”basins can be provided as pretreatment devices and should be installed at theoutfall of all storm drains prior to entering the lake.

将雨水处理功能融入水景设施中主要依赖于再造自然生态系统，利用生物过程处理地表雨水中的污染物，同时维持水景系统的正常健康。水景处理系统中所融入的主要元素包括：湿地植物、湖泊生物滤床、湿地预处理湿地、曝气、雨水蓄积体积/能力等，如果成功实施的话，可以实现相当好的水质效果。雨水的预处理对于增强整个系统的性能是很关键的因素，对于所有流入水景的进水都应事先接受预处理，以便清理较大的泥沙物。湿地植物或者种有植物的滤池盆可视为预处理装置，安装在所有雨水管的出口处。

Lake biofilters consist of separate self-containedsubmerged gravel beds adjacent to the perimeter of the lake through which lakewater is circulated and distributed underneath through a slotted pipesystem. A naturally occurring biologicalmass (microorganisms) will coat the gravel and serve to strip the water passingthrough the filter of nutrients (nitrogen, phosphorous) that would otherwisepromote algae growth. In addition, therecirculation pumping reintroduces oxygen into the lake system and increasesthe overall dissolved oxygen content. The combination of limited food supply andaerobic conditions reduce the potential for lake eutrophication. Generally, placement is recommended atterminal ends of the lake geometry which enhances the overall lake watercirculation. The biofilters are generally designed so that the velocity doesnot exceed 0.5 gpm per square foot, assuming minimum 24-inch thick gravelfilter. The number of biofilters neededto treat the lake system depends upon the amount of turnover or lake recirculationtime for treatment. Industry averages for lake turnover rates withoutbiofiltration range from 5 to 15 days.

湖泊生物滤池是在沿湖边附近的水底铺设的卵石床，湖水通过卵石床底部的割缝管进行循环和输配。自然而生的生物团（微生物）会附着在卵石表面，当水流经过时吸收其中所含有的氮、磷等养分。这些养分如果得不到清楚的话，会对藻类滋生起到促进作用。另外，循环水泵可以将氧气加入湖水中，增加了整体溶解氧的含量。在养分缺失和氧气充足的条件下，湖体出现富营养化的可能性就大大降低了。一般而言，生物滤池最好放置在湖泊的末端位置，这样可以促进整个湖体的循环效果。假定卵石的最低厚度为24英寸的话，生物滤池的设计要保证水流速度不超过0.5gpm/平方英尺。生物滤池的数量取决于换水水量以及湖体循环处理时间。在没有生物滤池的情况下，湖体换水速度的行业平均值为5-15天。

A stabilized biological lake systemrequires maintenance of the dissolved oxygen levels which will eliminate thepotential for odor problems and other lake operating issues. Maintaining the necessary dissolved oxygenlevels is achieved through the application of a fine bubble diffusion systemplaced along the bottom of the constructed lake. Additional benefits of aeration includedestratification of a lake’s water column to reduce surface water temperatureand enhancing the natural vertical movement or circulation patterns. Theaeration utilizes low-pressure and is sized to provide turnover every three tofour hours.

一个稳定的湖泊生物系统需要维持一定的溶解氧浓度，从而防止湖水出现异味以及其他运行问题。维持溶解氧浓度是通过利用放置在湖底的微孔曝气系统来实现的。曝气系统的另外一个益处是防止湖水出现分层，降低表面水温，增强水体垂直向的运动或循环方式。曝气系统所利用的压力很小，其规模尺寸的确定原则是每3-4小时交换一次。

Separate wetland planters periodicallylocated along the perimeter of the lake edge will assist in promoting theoverall water quality objective for the lake system. The wetland planters can be constructed alongshelves in the lake shoreline with walls separating the lake except for thecrest to allow for submergence from the lake water level. The wetlands function to filter out wastefrom the lake water through various natural chemical and biologicalprocesses. Methods to determine theamount of wetland area required for treatment involve correlations related tothe concentration or amount of nutrients in the lake water.

湿地植物沿着湖泊边缘布置，对于整个湖体的水质维持也有辅助作用。湿地植物的功能在于利用各种自然的生物和化学过程从湖水中清除污物。湿地植物面积要根据湖水中养分的浓度来确定。

Providing sufficient additional storagevolume to allow retention of some portion of the design stormwater runoffvolume will enhance the stormwater treatment capabilities of the aquascapesystem. The majority of stormwaterpollutants are captured in the initial ½ inch of runoff and retention of thisinitial storm volume will dramatically reduce pollutant levels through thesettling process prior to discharging to other downstream receivingwaters. In addition, once the water hasbeen retained in a constructed aquascape additional treatment can occur byrecirculation through lake biofilters and wetland planters. Linear constructed lake systems also have theadvantage of providing stormwater conveyance and can potentially significantlyreduce earthwork requirements on development projects.

在水景设系统中提供足够的额外蓄水空间，用于蓄积部分设计雨洪水量，可以增强水景系统的雨水处理能力。雨水中所含有的绝大部分污染物存在于地表径流最初的1.5寸中，如果在其流入下游受纳水体之前能够把这部分雨水蓄积起来，将大大降低污染物的浓度。另外，一旦水在人造水景中被蓄积之后，通过在生物滤池和湿地植物之间的循环可以对其进行净化处理。线状的构造湖泊系统还具备输配雨水的优点，这样可以大大降低项目开发中的土方开挖量。