基于逻辑构建与算法实现的拟自然水景参数化设计

“拟自然”水景设计从解读自然水景生成规律出发,充分结合地形条件,通过计算机技术辅助模拟自然形态与生态过程,生成拟自然的水景观系统。本文运用Grasshopper软件,紧扣水景构成关键要素,构建“形态—坝高—水量”动态关联,并根据参数化设计逻辑进行算法编写,建立参数化设计模型,实现水量、水体形态、工程量的多要素统筹设计与动态调控,优化设计方案。     

雨水回收利用生态工程及其应用——以中国科学院研究生院怀柔新校区为例

为了节约北京市的水资源,减少雨水中所携带的污染物排放对环境造成的污染,结合中国科学院研究生院怀柔新校区即将建设的实际工程,对怀柔区的自然环境特征进行了调查,并根据现有校园规划设计方案,对园区内水量平衡进行计算,在最大化收集雨水和剩余中水的基础上,得出为保持园区内水量平衡,每月所需补充或外排的水量。同时,基于水量平衡表所得出的园区内水量较为丰富的结果,采用了自然回收净化、部分间接利用的雨水回收利用生态工程,并提出雨水回收利用流程的方案:针对校园内不同汇水面上的雨水质量不同的特点,分别对它们设计了不同的回收方法,使之最终汇入园区内的景观水系。景观水体中的水通过景观水处理装置进行循环处理,保证水的质量。灌溉绿化及清洗道路可直接抽取景观水使用。应用雨水回收生态工程取得了很好的生态效益与社会效益,既节约了水资源,又可以补充地下水源,防洪减排,还能减少雨水所携带的污染物对环境的破坏。     

文化——水利风景区的千古传承

水,作为自然的元素、生命的依托,从一开始便与人类生活乃至文化历史形成了一种不解之缘。水利风景区以水为主体,以水为重要景观和环境背景的载体。没有水,缺少水景支撑,水利风景区则不复存在;水不美,水量不足,水利风景区则失去色彩。保护水与水生态系统,是水利风景区的立身之本。水利风景区不仅要有水,而且要有优美的环境以及水文化。建设和经营水利风景区,必须要以水文化为主题,做大做强水文化产业,水利风景区才能更好地发展。     

苗期杨树生长和光合特征在不同水分梯度和施肥下的比较分析

为提高水肥效率,指导杨树科学浇水施肥,以华石2号杨为材料,通过不同的水、肥配比试验,对其生长和光合特征进行比较分析。结果显示:水分和施肥量双因素方差分析发现,不同土壤水分间,苗高和地径差异均显著(P<0.05),不同施肥量间,地径差异显著(P<0.05),而苗高差异不显著,生长表现最差的为A4B4(自然雨水, 0 g复合肥)处理,生长最好的为A2B2(80%—85%田间持水量, 15 g复合肥)处理。无论是不同施肥处理还是水分处理,植株叶片数差异均显著(P<0.05),A4B1(自然雨水,21g复合肥)处理的单株叶片数最少,均值为17.67片,而A1B2(95%—100%田间持水量, 15 g复合肥)处理的单株叶片数最多,均值为39.00片。比较发现,叶片叶绿素含量比较低的主要是施肥量少的几个处理,叶绿素含量比较高的主要是施肥量较高的处理。光饱和点(PLS)最大为处理A1B1(95%—100%田间持水量,21g复合肥),达到1961.59μmol·m-2·s-1,处理A2B1(80%—85%田间持水量,21g复合肥)的最大净光合速率(Pnmax)最高(24.75μmo...     

遥感和GIS辅助下流域养分迁移过程的计算机模拟

农业非点源污染问题已成为我国重要的环境污染类型之一．利用空间模型对流域N、P的迁移过程进行计算机模拟,是研究非点源污染控制方法的一个有效手段．设计了遥感和GIS技术辅助下的流域水分和养分迁移过程分布式的模拟方法,包括模型选择、流域的空间离散化和参数化、模型模拟和结果验证3个步骤,为控制流域水肥流失提供了思路．以江西兴国潋水河流域(579km^2)为研究区域,选择美国农业部设计的SWAT模型,设计了流域．子流域-水文响应单元的空间离散方案和实现步骤．首先依据地形特征,将整个流域分割成多个子流域,每个子流域内部通过叠加统计分析,生成单一土地利用类型和土壤类型组合的水文响应单元．土地利用参数用TM遥感图像进行监督分类获得,土壤参数化利用地统计学采样和插值分析获得．对1991～2000年的初步预测结果表明,SWAT模型能够较好地模拟潋水河流域的径流水量和泥沙的变化,产水和产沙10年平均预测精度分别为89．9％和70．2％．     

遥感和GIS辅助下流域养分迁移过程的计算机模拟

农业非点源污染问题已成为我国重要的环境污染类型之一.利用空间模型对流域N、P的迁移过程进行计算机模拟,是研究非点源污染控制方法的一个有效手段.设计了遥感和GIS技术辅助下的流域水分和养分迁移过程分布式的模拟方法,包括模型选择、流域的空间离散化和参数化、模型模拟和结果验证3个步骤,为控制流域水肥流失提供了思路.以江西兴国潋水河流域(579km²)为研究区域,选择美国农业部设计的SWAT模型,设计了流域-子流域-水文响应单元的空间离散方案和实现步骤.首先依据地形特征,将整个流域分割成多个子流域,每个子流域内部通过叠加统计分析,生成单一土地利用类型和土壤类型组合的水文响应单元.土地利用参数用TM遥感图像进行监督分类获得,土壤参数化利用地统计学采样和插值分析获得.对1991～2000年的初步预测结果表明,SWAT模型能够较好地模拟潋水河流域的径流水量和泥沙的变化,产水和产沙10年平均预测精度分别为89.9%和70.2%.     

亚高山森林自然与人工恢复对土壤涵水能力的影响

西南亚高山原始针叶林被大规模采伐后,在皆伐迹地上营造了大量云杉林进行人工恢复。但关于这些人工林的土壤涵水能力如何,一直没有系统深入的研究与评价。选择川西米亚罗林区系列不同林龄云杉人工林(20 a、30 a、40 a、70 a)为对象,以相邻同龄自然更新恢复的针阔混交林为对照,比较人工林土壤涵水能力随着演替进程的动态及其与自然恢复次生林之间的差异,结合人工与自然恢复后的林地特征(如细根生物量、凋落物储量和土壤有机碳等)和土壤物理结构参数等差异,阐释自然与人工恢复后土壤涵水能力差异的影响因素。结果显示:随着人工林演替,土壤0—40 cm层最大持水量随林龄的增加而降低,但变化不显著,从20年的2200 t/hm~2下降到70年的2138 t/hm~2,年平均下降速率为1.24 t/hm~2;然而在自然次生林中,土壤最大持水量随着林龄的增加呈现出波动式变化,从20年的2142 t/hm~2增加到40年的2565 t/hm~2,到70年又下降为2302 t/hm~2。通过土壤持水特性与林地凋落物贮量、细根生物量和土壤物理结构参数的相关分析表明,由不同恢复途径导致的林地土壤有机碳含量、凋落物特性及细根差异,进而改变土壤物理结构是影响土壤持水性能差异的主要因素。这些结果说明,从土壤持水量角度考虑,在对采伐迹地进行造林恢复时,应尽量避免营造结构单一、高密度的人工纯林,应选择营造针阔混交林的模式进行恢复。     

杉木人工林蒸散规律的研究及乱流扩散法应用的探讨

 本文根据乱流扩散法原理,利用实验集水区连续6年实测数据,对杉木人工林蒸散规律进行了探讨。结果表明：杉木人工林年平均蒸散量875.45mm,占年降雨量的82.2%。其中,林冠蒸散量781.77mm,林地93.68mm,分别为总蒸散量的89.3%和10.7%。与水量平衡法的结果比较,为水量平衡法的101.2%。在研究蒸散规律的同时,对乱流扩散法的应用及参数的估算也进行了较详细的分析。     

水螨群总科阶元系统发育的支序分析 (蜱螨亚纲：水螨群)

对水螨群9总科进行了系统发育分析,支序分析选用了23个形态学特征和3个生物学特征。据分析结果所揭示的9总科间的系统发育关系和姐妹群关系,将水螨群9总科划分为5类：拟水螨类,含冥绒螨总科;始水螨类,含溪螨总科;真水螨类,含古水螨类和新水螨类;古水螨类,含水螨总科、盾水螨总科和皱喙螨总科;新水螨类,含刺触螨总科、腺水螨总科、湿螨总科和雄尾螨总科。类间姐妹群关系为：拟水螨类与始水螨类+真水螨类为姐妹群,始水螨类与真水螨类(古水螨类+新水螨类)为姐妹群,古水螨类与新水螨类为姐妹群。该文还就所提出的水螨群5类9总科的阶元排列建议与已有的观点进行了比较。     

乐山市动物类产品水足迹测算分析

产品水足迹能反映人类活动在产品全生命周期中对水资源的消耗情况, 为水资源的合理分配和利用提供科学依据。以乐山市为例, 运用水足迹的理论和方法, 测算了动物从出生到出栏过程中的虚拟水量以及出栏后加工成肉类产品期间的生产用水量。结果显示: 乐山市动物产品总水足迹在2000-2011 年呈上升趋势, 2011 年较2000 年总水足迹增加了22.23 亿立方米。比较不同种类动物产品水足迹, 由大到小为牛肉>羊肉>猪肉>其它禽肉>兔肉>水产品>禽蛋>奶类。从水足迹构成看, 年虚拟水量占总水足迹的比重在56.03-60.70%之间。动物产品的耗水环节主要为饲料用水以及出栏后动物产品的加工过程, 建议采取改善饲料成分、改变养殖模式以及加强虚拟水贸易等措施, 从而有效降低动物产品的水足迹。     

内陆河干旱区生态需水分析

根据水分驱动生态演变模型 ,以水分运动和补给条件 ,研究了内陆河平原生态系统的需水结构。生态需水分为过渡带生态需水 ,绿洲生态需水 ;绿洲生态需水又进一步分为天然绿洲生态需水和人工绿洲生态需水。通过流域水分平衡和地面观测资料确定了生态圈层结构的水分需求 ,以及降水与径流对水分需求的补给比例。生态需水的分析计算 ,类似于供需平衡分析。从植物生理角度分析生态需水 ,得到天然植被的总腾发量 Et,作为植被生态需水总量。各典型天然植被的 Et通过实验资料获得。将植被和水面的总生态需水量扣除有效降水补充的部分 ,即为径流性生态需水量 GE。另一方面 ,以流域为单元进行降水和径流统一考虑的水分综合平衡 ,进行生态可利用水量分析。得到生态系统可能实际利用的径流性水资源量 GR。　　将生态需水量 GE与生态系统可能实际利用的水资源量 GR进行平衡分析 ,计算实际生态耗水 ,并分析盐碱地无效耗水。根据 2 0 2 0年生态状态情景分析 ,作出了 2 0 2 0年生态需水与生态系统结构演变的预测     

Urban Water Mass Balance Analysis

Planning for “water‐sensitive” cities has become a priority for sustainable urban development in Australia. There has been little quantification of the term, however. Furthermore, the water balance of most cities is not well known. Following prolonged drought, there has also been a growing need to make Australian cities more water self‐reliant: to source water from within. This article formalizes a systematic mass‐balance framework to quantify all anthropogenic and natural flows into and out of the urban environment. Quantitative performance indicators are derived, including (1) degree of system centralization; (2) overall balance; potential of (3) rainfall, (4) stormwater, and (5) wastewater to offset current demand; and (6) water cycle rate. Using the method, we evaluate Sydney, Melbourne, South East Queensland and Perth using reported and modeled data. The approach makes visible large flows of water that have previously been unaccounted and ignored. It also highlights significant intercity variation. In 2004–2005, the cities varied 54% to 100% in their supply centralization, 257% to 397% in the ratio of rainfall and water use, 47% to 104% in their potential stormwater recycling potential, and 26% to 86% in wastewater recycling potential. The approach provides a practical, water‐focused application of the urban metabolism framework. It demonstrates how the principles of mass balance can help foster robust water accounting, monitoring, and management. More important, it contributes to the design and quantitative assessment of water‐sensitive cities of the future.     

基于控水试验的喀斯特出露基岩生境植物水分来源分析

裂隙发育的喀斯特出露基岩生境,虽无土层覆盖却能维持不同生活型植物的水分消耗.然而目前对该类生境植物的水分来源缺乏清晰认识.本研究以植物潜在水分来源相对简单的孤立出露基岩为例,聚焦遮雨(即剔除雨水对浅层水源的补给)1年后仍然生长旺盛的代表性植物种,同时以无遮雨处理样地(即始终接受降雨补给)的同种植物为对照,运用稳定性氢氧同位素技术,结合对植物水势的测定,综合分析了3种典型植物(落叶乔木菜豆树、落叶乔木紫弹树、常绿灌木四子海桐)的水分来源.结果表明: 在降水充沛的雨季,遮雨条件下3种植物均依赖与泉水同位素比率相近的深层水源,这是植物在遮雨1年后仍能正常生长的根本原因;遮雨菜豆树和四子海桐凌晨水势与自然植株无显著差异,表明植物未受水分胁迫,而紫弹树凌晨水势显著低于自然植株,表明其受一定程度的水分胁迫;自然条件下,3种植物茎水同位素比率均显著低于遮雨植株,且处于近期雨水同位素比率波动范围内,表明植物均依赖受近期雨水主导的浅层水源.遮雨和自然条件下,四子海桐正午水势与凌晨水势始终无明显差异,表现出较为保守的水分利用策略;另外2种植物正午水势显著低于凌晨水势,属于偏挥霍型水分利用策略.具备利用浅层和深层水源的能力是喀斯特无土覆盖出露基岩生境植物适应不同水分环境和维持多样化水分利用策略的关键.     

Semiarid Crop Production from a Hydrological Perspective: Gap between Potential and Actual Yields

Rapid population growth in the dry climate regions, arable land scarcity, and irrigation expansion limitations direct our interest to possibilities of yield increase in rainfed agriculture. Literature, however, indicates large differences between actual and potential yields, and between yields on farmers’ fields and research stations. This article focuses on the determinants of these yield gaps and the windows of opportunity for yield increase on the farmer's field together with the agricultural challenges involved. The study links the conventional approach to estimate crop water requirements and dry spell effects on biomass production to a conceptual Green Water Crop Model. This model addresses the effects on crop yields of the sequential diversions of infiltrating rainfall (rainwater partitioning into runoff, plant available soil water, and deep percolation) and of different relations between nonproductive evaporation flow and productive transpiration flow, defined together as green water flow. Also, the effects of droughts and dry spells are analyzed. The model is used to demonstrate typical situations for semiarid and dry subhumid conditions (lengths of growing period (LGP) of 90 and 179 days, respectively) for maize (Zea mays (L.)) under on-station agricultural conditions. Based on detailed water flow analysis in a 3-year on-farm case study in the Sahel on pearl millet (Pennisetum glaucum (L.) Br.), the model is used to clarify the large scope for improved yield levels, achievable through land and water management securing that runoff losses and deep percolation are reduced and nonproductive evaporation losses minimized. The analysis indicates that poor rainwater partitioning and low plant water uptake capacity alone reduces estimated on-farm grain yields to 1/10th of the potential yields. This suggests that lack of water per se not necessarily is the primary constraint to crop growth even in drought prone areas of sub-Saharan Africa. The conclusion is that even a doubling of crop yields would be agro-hydrologically possible with relatively small manipulations of rainwater partitioning in the water balance.     

延安公路山辽东栎林优势植物水分适应性及适应类型分析

以陕西省延安公路山辽东栎林群落为对象,测定林内外不同状态下12种优势植物的水势日进程、自然饱和亏、临界饱和亏等水分利用参数,分析它们在林内和林外孤立木状态下的水分利用多样性和水分平衡策略,以揭示辽东栎群落水分利用多样性在群落持续发育中的作用.结果表明:(1)在林内或林外12种优势植物的水势日变化趋势基本一致,一天内每一时段物种间水势值跨度不同,林内种间水势跨度为0.85～1.93 Mpa,林外种间水势跨度为0.6～1.83Mpa;林内物种间日最低水势(-1.43～-3.05 Mpa)及临界饱和亏(63.12%～92.59%)变幅较大;各优势植物水势日进程与气象因子显著相关.(2)林内外各时段物种间水势跨度不同,14:00和17:00林外物种间水势跨度大于林内;12种植物的水势日变化与林内有显著差异(P<0.05),且在林内和林外环境下水分参数具有相似变化趋势.(3)根据黎明前水势、日最低水势、自然饱和亏、临界饱和亏将辽东栎林内12种优势植物水分利用策略聚类分为 4个水分适应类型,每个适应类型具有特殊的水分适应方式.可见,辽东栎群落内12种优势植物的水分利用参数及其对环境适应表现出多样性特点,为该群落持续发育奠定了基础.     

How afforestation affects the water cycle in drylands: A process‐based comparative analysis

The world's largest afforestation programs implemented by China made a great contribution to the global “greening up.” These programs have received worldwide attention due to its contribution toward achieving the United Nations Sustainable Development Goals. However, emerging studies have suggested that these campaigns, when not properly implemented, resulted in unintended ecological and water security concerns at the regional scale. While mounting evidence shows that afforestation causes substantial reduction in water yield at the watershed scale, process‐based studies on how forest plantations alter the partitioning of rainwater and affect water balance components in natural vegetation are still lacking at the plot scale. This lack of science‐based data prevents a comprehensive understanding of forest‐related ecosystem services such as soil conservation and water supply under climate change. The present study represents the first “Paired Plot” study of the water balance of afforestation on the Loess Plateau. We investigate the effects of forest structure and environmental factors on the full water cycle in a typical multilayer plantation forest composed of black locust, one of the most popular tree species for plantations worldwide. We measure the ecohydrological components of a black locust versus natural grassland on adjacent sites. The startling finding of this study is that, contrary to the general belief, the understory—instead of the overstory—was the main water consumer in this plantation. Moreover, there is a strict physiological regulation of forest transpiration. In contrast to grassland, annual seepage under the forest was minor in years with an average rainfall. We conclude that global long‐term greening efforts in drylands require careful ecohydrologic evaluation so that green and blue water trade‐offs are properly addressed. This is especially important for reforestation‐based watershed land management, that aims at carbon sequestration in mitigating climate change while maintaining regional water security, to be effective on a large scale.     

北京城市绿地调蓄雨水径流功能及其价值评估

随着城市化进程的加快,城区不透水面积急剧增加,改变了城市自然水循环。充分认识与发挥城市绿地调蓄雨水径流的积极作用,对于城市生态环境的改善和绿地资源的建设管理具有重要意义。本文以2009年北京城市园林绿地调查数据为基础,采用径流系数法和影子价格法评估了绿地调蓄雨水径流的功能及其价值。结果表明：2009年北京城市绿地生态系统调蓄雨水径流1.54亿m3,单位面积绿地调蓄雨水径流2494 m3/hm2;绿地年调蓄雨水径流价值13.44亿元,约合2.18万元/hm2;不同区县绿地调蓄雨水功能主要受其面积影响,朝阳区绿地调蓄雨水径流及其价值量最高,其次为海淀区、顺义区、丰台区区和通州区绿地,而密云县、怀柔区和门头沟区绿地调蓄雨水径流能力及其价值较低。本研究对于认识北京城市绿地的功能与价值、促进城市绿地的科学管理和建设维护具有一定的指导意义。     

Water balance in the arborescent palm, Sabal palmetto. II. Transpiration and stem water storage

The contribution of stem water storage to the water balance of the arborescent palm, Sabal palmetto, was investigated using greenhouse studies, field measurements and a tree-cutting experiment. Water balance studies of greenhouse trees (1.5 to 3 m tall) were conducted in which transpiration was measured by weight loss, and changes in soil and stem water content by time-domain reflectometry. When the greenhouse plants were well-watered (soil moisture near saturation), water was withdrawn from the stem during periods of high transpiration and then replenished during the night so that the net transpirational water loss came primarily from the soil. As water was withheld, however, an increasing percentage of daily net transpirational water loss came from water stored in the stem. However, studies on palms growing in their natural environment indicated that during periods of high transpiration leaf water status was somewhat uncoupled from stem water stores. In a tree-cutting experiment, the maintenance of high relative water content of attached leaves was significantly correlated with stem volume/leaf area. Leaves of a 3-m tree remained green and fully hydrated for approximately 100d after it had been cut down, whereas those of a 1-m-tall plant turned brown within one week. The significance of stem water storage may be in buffering stem xylem potentials during periods of high transpiration and in contributing to leaf survival during extended period of low soil water availability.     

基于暴雨径流管理模型的海绵城市景观格局优化模拟

随着我国城镇化进程加快,城市不透水面积急剧增加,城市内涝问题日益严重.为此我国基于低影响开发理念提出了海绵城市概念.本研究以辽宁省沈抚新城中心城区作为研究区域,利用暴雨强度公式构建不同重现期的降雨过程,基于海绵城市理念对研究区进行景观格局优化,并运用暴雨径流管理模型模拟预规划方案和景观格局优化方案两种情景下的地表径流和雨水调控能力的差异,分析景观格局优化方案对城市地表径流和雨水调控能力的影响.结果表明: 随着降雨重现期的增大,研究区内径流总量和径流系数呈上升趋势;在相同降雨重现期下,景观格局优化方案的径流系数明显降低,径流总量的削减量逐渐增加,1年一遇、3年一遇、5年一遇和50年一遇重现期下的削减量分别为2.94、3.58、3.72、4.19 mm;相对应的削减率逐渐降低,分别为23.9%、16.4%、14.3%、9.3%;优化后的方案可满足降雨重现期p=1时设计降雨量20.8 mm、p=3时雨水管网不超载且p=50时河道不溢流的要求.     

Water sources of dominant species in three alpine ecosystems on the Tibetan Plateau, China

Plant water sources were estimated by two or three compartment linear mixing models using hydrogen and oxygen isotope （δD and δ^18O） values of different components such as plant xylem water, precipitation and river water as well as soil water on the Tibetan Plateau in the summer of 2005. Four dominant species （Quercus aquifolioides, Pinus tabulaeformis, Salix rehderiana and Nitraria tangutorum） in three typical ecosystems （forest, shrub and desert） were investigated in this study. Stable isotope ratios of the summer precipitations and the soil water presented variations in spatial and temporal scales. δ^18O values of N. tangutorum xylem water were constant in the whole growth season and very similar to those of deep soil water. Water sources for all of the plants came from both precipitations and soil water. Plants switched rapidly among different water sources when environmental water conditions changed. Rainwater had different contributions to the plants, which was influenced by amounts of precipitation. The percentage of plant xylem water derived from rainwater rose with an increase in precipitation. Water sources for broad-leaved and coniferous species were different although they grew in the same environmental conditions. For example, the broad-leaved species Q. aquifolioides used mainly the water from deep soil, while 92.5% of xylem water of the coniferous species P. tabulaeformis was derived from rainwater during the growth season. The study will be helpful for us to fully understand responses of species on the Tibetan Plateau to changes in precipitation patterns, and to assess accurately changes of vegetation distribution in the future.