Vulnerability of Kenya’s Water Towers to Future Climate Change: An Assessment to Inform Decision Making in Watershed Management

Recent trends show that in the coming decades, Kenya’s natural resources will continue to face significant pressure due to both anthropogenic and natural stressors, and this will have greater negative impacts on socio-economic development including food security and livelihoods. Understanding the impacts of these stressors is an important step to developing coping and adaptation strategies at every level. The Water Towers of Kenya play a critical role in supplying ecosystems services such as water supply, timber and non-timber forest products and regulating services such as climate and water quantity and quality. To assess the vulnerability of the Water Towers to climate change, the study adopted the IPCC AR4 framework that defines vulnerability as a function of exposure, sensitivity, and adaptive capacity. The historical trends in rainfall indicate that the three Water Towers show a declining rainfall trend during the March-April-May (MAM) main rainy season, while the October-November-December (OND) short rainy season shows an increase. The temperature patterns are consistent with the domain having a common rising trend with a rate in the range of 0.3°C to 0.5°C per decade. Projection analysis considered three emissions scenarios: low-emission (mitigation) scenario (RCP2.6), a medium-level emission scenario (RCP4.5), and a high-emission (business as usual) scenario (RCP8.5). The results of the high-emission scenario show that the annual temperature over the Water Towers could rise by 3.0°C to 3.5°C by the 2050s (2036-2065) and 3.6°C to 4.8°C by the 2070s (2055-2085 results not presented), relative to the baseline period 1970-2000. The findings indicate that exposure, sensitivity, and adaptive capacity vary in magnitude, as well as spatially across the Water Towers. This is reflected in the spatially variable vulnerability index across the Water Towers. Overall vulnerability will increase in the water towers leading to erosion of the resilience of the exposed ecosystems and the communities that rely on ecosystem services these landscapes provide.

Contribution of the cryosphere to runoff in“Chinese water tower”based on environmental isotopes

Cryospheric meltwater is an important runoff component and it profoundly influences changes in water resources in the Tibetan Plateau.Significant changes in runoff components occur in the three-river headwater region(TRHR),which is an important part of“Chinese Water Tower”due to climate warming.However,these effects remain unclear owing to the sparse and uneven distribution of monitoring sites and limited field investigations.Quantifying the contribution of cryospheric meltwater to outlet runoff is a key scientific question that needs to be addressed.In this study,we analyzed 907 precipitation,river water,ground ice,supra-permafrost water,and glacier snow meltwater samples collected from October 2019 to September 2020 in the TRHR.The following results were obtained:(1)There was significant spatio-temporal variation in stable isotopes in different waters;(2)The seasonal trends of stable isotopes for different waters,the relationship between each water body and the local meteoric water line(LWML)confirmed that river water was mainly recharged by precipitation,supra-permafrost water,and glacier snow meltwater;(3)Precipitation,supra-permafrost water,and glacier snow meltwater accounted for 52%,39%,and 9%of river water,respectively,during the ablation period according to the end-member mixing analysis(EMMA);(4)In terms of future runoff components,there will be many challenges due to increasing precipitation and evaporation,decreasing snow cover,glacier retreat,and permafrost degradation.Therefore,it is crucial to establish the“star-machine-ground”observation networks,forecast extreme precipitation and hydrological events,build the“TRHE on the Cloud”platform,and implement systematic hydraulic engineering projects to support the management and utilization of water resources in the TRHR.The findings of environmental isotope analysis provide insights into water resources as well as scientific basis for rational use of water resources in the TRHR.

Importance and vulnerability of water towers across Northwest China

High mountains(known as water towers)in the arid areas of Northwest China(ARNWC)are major suppliers of water resources for the downstream oasis region,where large populations and economic activities are concentrated.Studies on both water supply and water demand in central Asia including ARNWC have been explored in recent decades,but a precise study on the importance and vulnerability of fine-scale water towers still needs to be conducted,because oases are isolated each other and each oasis has its own specific tower(s).Here we ranked the importance of water tower units(WTUs)using a simplified water tower index(WTI)based on water amount of supply/demand side at a fine river basin scale.Then the vulnerability of these WTUs is assessed with the consideration of future changes in climate,population.GDP,water stress,etc.We con eluded that the WTU of the Mid-branch Rivers of the Junggar Basin is the most important with the highest WTI.while the Yarkant River Basin is the most vulnerable.The WTUs such as the Yarkant,Hotan and Kaxgar of the Tarim River Basin as well as the Hei River of the Hexi Corridor are important at present and vulnerable under a considerable pressure from future climate change scenarios.To respond to these opportunities and risks,it is better to reduce the proportion of the primary industry appropriately,improve the efficiency of water use and strengthen the supervision of water resources utilization,especially in the industrial and urban planning as well as ecological engineering projects.

A New Water Saving Device of Swirling Flow for Cooling Towers

This paper is concerned with water saving for water-loop cooling tower system in power plants. A newly developed water saving device of swirling flow is presented. The key point is that the new water saving device makes the steam swirl up along the device wall rather than engender laminar flow in a corrugated plate. The corrugated plate device can save approximately 10 percent of the total lost water. In contrast to the scale model of corrugated plate water saving device, experimental analyses have demonstrated that the new water saving device of swirling flow is more efficient, with a capacity of saving more than 20 percent of water.

某大科学装置项目工艺冷却水系统设计

介绍了某在建大科学装置项目的工艺冷却水系统设计,包括服务对象、系统形式、系统组成、水温控制策略、流量控制策略等方面的内容。简述了热回收型水源热泵在工艺冷却水系统中的应用方案,并对工艺冷却水系统设计后续可开展的工作和研究提出了3个方向。

温升背景下“亚洲水塔”流域水资源压力现状及未来预估

“亚洲水塔”流域养育着亚洲十几亿人口,对全球经济发展起着至关重要的作用。在气候变暖背景下,“亚洲水塔”流域的水资源快速变化以及不断增长的人类活动用水需求,使水塔流域水资源压力风险越显突出。为了解“亚洲水塔”流域水资源压力的状况及未来变化,基于部门间影响模式比较计划(ISIMIP)中全球水文模型的径流和用水数据,利用水压力指数方法,系统评估了“亚洲水塔”21个流域的水压力状况和未来的可能变化。结果表明:1971—2010年间,“亚洲水塔”21个流域的水压力总体上呈现升高趋势,多年平均水压力等级达到高或以上的流域为印度河流域、塔里木河流域和黄河流域;针对“亚洲水塔”21个流域未来水压力的变化预估,各流域水压力表现为先增加,之后不同流域表现出持续增加(2个流域)、趋于稳定(5个流域)和下降(14个流域)三种趋势,人类取水活动在未来水压力的变化中起决定性作用。整体上,南亚和东南亚地区水压力将持续增加,例如,布拉马普特拉河流域和湄公河流域,未来水资源短缺和水安全风险很高。

深圳北坑水库取水塔交通桥地震动力响应规律及抗震安全性研究

取水塔交通桥是水库进水建筑物的组成部分,其抗震性能对保证水库震后安全运行具有重要意义。以深圳北坑水库取水塔交通桥为研究对象,采用有限元动力分析方法开展结构地震响应分析,并对交通桥的抗震安全性进行评价。研究表明:设计地震作用下,交通桥最大横桥向地震动位移3.15 cm,各跨桥板间在地震过程中的最小距离2.97 cm,地震过程中不会发生落梁破坏,也不会发生相邻跨桥面板碰撞现象;交通桥对地震产生明显放大作用,设计地震条件下,桥面板横桥向地震加速度放大倍数最大值4.01,顺桥向加速度放大倍数最大值3.36;设计地震过程中,各桥墩排架墩柱动剪应力水平不高,不会发生墩柱剪断破坏,但桥墩柱底部外侧竖直向动拉应力值较大,桥墩排架下部横梁在顶面和底面都出现较高的动拉应力,需要配置抗震钢筋来保证桥墩排架结构的抗震安全性。

大型冷凝式消雾节水冷却塔性能试验研究

为研究获得菱形模块消雾节水冷却塔的消雾节水和节能特性,对某设计循环水量为5000 m^(3)/h的菱形消雾节水冷却塔的消雾性能、节水性能和节能性能进行了试验研究。建立了冷却塔消雾节水节能性能评价模型,通过现场试验获得冷却塔消雾节水和节能特性参数及其变化规律。结果表明:消雾节水冷却塔设计出塔空气相对湿度为85%,实测出塔相对湿度为82.28%,消雾指数为1.03,符合“零雾型”消雾冷却塔的要求。经菱形消雾冷凝模块换热后的冷凝水量为14.19 m^(3)/h,冷却塔节水率为25.3%,冷凝节水效果好。单塔年总节能收益约40万元,整体年节能收益达240万元,菱形消雾节水冷却塔具有良好的经济效益及环保效益。

JP72举高喷射消防车支腿反力与稳定性分析

举高喷射消防车是重要的消防装备类产品,当其折叠臂完全展开时,等效受力点与回转中心之间的跨距将达到数十米,这将对消防车的稳定性提出更高要求。同时,水炮冲击力及风力等均会对消防车的稳定性产生较大影响,严重时将导致车辆前倾或侧翻。为避免上述危险工况,该文以72 m举高喷射消防车为对象展开稳定性分析,在充分考虑各因素的影响情况下进行C++编程,并依照相关标准计算其等效作用点及作用力,计算出各支腿受力数值,最后依照国家标准以及合力圆分析进行稳定性检验,所研究内容为同类型分析计算工作提供了一定的参考。

低温甲醇洗装置系统排水存在的问题及改造措施

介绍了国能榆林化工有限公司低温甲醇洗装置大检修期间排水系统存在的问题,分析了系统固体杂质的来源以及对不同塔器设备的影响。针对废水输送流程复杂,易造成热再生塔和甲醇水分离塔塔盘堵塞,固体杂质再次带入系统等问题,在排放甲醇泵出口阀后至废水外送液位调节阀后配置一条管线,实现了高效安全的排水,避免了废水中的固体杂质再次带入后堵塞系统的风险,同时降低了洗涤水输送电耗。

开式消雾节水技术在工业循环冷却水中的应用

循环冷却水系统节水是工业企业节水、节能的一个重要环节。常规开式循环冷却水塔因塔顶排放口易产生大量白雾,造成水资源的浪费;新型冷凝模块消雾节水冷却塔技术在消除白雾和节水方面成效显著,近年来受到广泛关注。分析了消雾节水冷却塔的消雾节水及工作原理,并与常规开式冷却塔进行了基本参数、运行费用、投资等方面的初步对比。初步估算,消雾节水冷却塔与常规冷却塔相比,蒸发水量和排污量可减少约20%,设备投资增加约80%,但整体运行费用较低,其投资成本在两年左右即可收回,在化工行业具有较好的应用前景。

低温甲醇洗系统甲醇中水含量高的异常现象及应对实践

针对华鹤公司低温甲醇洗系统甲醇中水含量高带来甲醇吸收效率低、系统腐蚀、影响系统负荷等问题进行了原因分析,发现是由甲醇/水分离塔工况不稳定所致。为此,进行了增加原料气分离罐物料过滤器、尾气水洗塔增加自动控制碱液系统、降低甲醇/水分离塔废水排放温度等技术改造,解决了甲醇/水分离塔管道及设备外漏的问题,保证了甲醇/水分离塔的稳定运行。

空分设备冷却水系统技术改造总结

夏季高温,针对35 000 m^(3)/h空分设备循环冷却水温度与分子筛吸附器进气温度大于高报警值问题,对空分设备循环冷却水系统增设冷却风机、空气预冷系统增设冷冻机,保障空分设备在夏季高温条件下安全、稳定、经济运行。叙述35 000 m^(3)/h空分设备在夏季高温状态运行时,循环冷却水温度与分子筛吸附器进气温度大于高报警值的原因,介绍35 000 m^(3)/h空分设备增设冷却风机与冷冻机技术改造的具体措施、效果。

乙炔装置生产异常事件分析

介绍了乙炔装置的几起生产异常事件,分析了事故出现的原因,提出了整改方案及预防措施。

空分装置预冷系统冷冻水流量降低原因分析与防范

对某公司大型空分装置预冷系统冷冻水流量降低的原因进行分析,认为脱盐水硬度过大和含尘量高致使管道等结垢是预冷系统冷冻水流量降低的主要原因。针对性地采取一系列预防和处理措施后,冷冻水流量恢复至设计值,空冷塔出口压缩空气温度明显下降,减少了装置能耗,提高了生产效率,后续分子筛吸附系统负荷也有所降低,为空分装置的长周期、稳定运行提供了保障。

屋面冷却泵气蚀现象的分析与处理

结合工程实际,对屋顶的冷却水泵产生振动和噪声背后的气蚀现象的原因进行了分析。结合理论计算得出冷却水泵与冷却塔之间的需求高度差,完成了对案例工程系统冷却水侧的改造,使该系统良好运行。同时,总结了通过改变水泵入水口压头以避免气蚀现象的方法,以期为类似工程提供经验参考。

倒锥壳水塔装配式环形可调节托架设计及应用

倒锥壳水塔是一种运用于高速公路服务区的常见储水结构,它的传统施工方式有满堂支架法和地面预制提升法,这两种工艺内部支撑错综复杂,传力路径不明确、不规则,存在较多安全隐患。本文设计了一种装配式环形可调节托架,配合支架平台可实现规范倒锥壳水塔箱体的模板支撑,同时该托架安装便捷且适配不同倾角的倒锥壳水塔施工,大幅提高了现场施工效率与安全性。

汉口城堡暨中山大道城市演变研究

文章以中山大道为研究对象,通过街道的发展历程和历史文化资源现状来总结汉口城市发展的演变机制及特色。首先,对中山大道的前身汉口城堡进行溯源,还原汉口城堡通济门及城墙,梳理该街道从汉口城堡发展至中山大道的演变历程。其次,考察汉口水塔周边的城市风貌变化,对比分析中山大道沿线道路、建筑的风貌变化。最后,对汉口城堡及中山大道的修建时间、中山大道及玉带河的位置关系进行时间、空间上的考证。中山大道的历史文化资源丰富,从汉口城堡到中山大道不仅是名称上的转变,更是从防洪堤坝到交通观光功能的转变,其见证了汉口城市面貌的变化,为保障和促进汉口发展提供了不竭动力。

水浴式汽化器节水降耗研究与应用

水浴式汽化器是一种将水加热,以水为传热介质,将液态气体转化为气态气体的设备。在大型空分装置中,水浴式汽化器的作用是将液态氧、氮等气体吸收足够的热量,使其转变为气态,以满足工业生产的需求。在正常运行时,我公司水浴式汽化器需不断补入一次水保证满液位,使盘管能够全浸其中,保证换热充分,此技术改造的特点是在设备本体上增加了就地液位计,通过补水阀将液位控制在不低于换热管束高度,不高于溢流口高度的限范围内;水浴式汽化器改造后在运行期间,将水浴式汽化器内的液位控制在上下限范围内,且经过多次长时间运行试验,能够满足其实际运行需求,未出现过水浴式汽化器出口温度不达标的问题,彻底解决了溢流水直排问题,为公司节水减排管理及环保管理工作降低了难度和风险,既满足了“节水减排”要求,又能长期稳定运行。

大功率水冷螺杆空压机换热分析与研究

功率为315 kW及以上的螺杆空压机在运行时会释放出大量的热量,为保证螺杆空压机的稳定运行,根据热力学第一定律及对流换热公式,通过对大功率水冷螺杆空压机热量分布及传热过程进行分析与研究,给出了螺杆压缩机组其冷却系统的设计计算方法:包括空压机的循环喷油量,油冷却器换热面积,后冷却器换热面积,冷却水进出水温度,冷却水塔换热参数,冷却水泵流量与扬程等参数进行了分析与计算,能够为大功率水冷螺杆空压机冷却系统的设计提供了较好的指导意义。