Syed Azizul Haq, PEng Harvesting Rainwater from Buildings Harvesting Rainwater from Buildings Syed Azizul Haq, PEng Harvesting Rainwater from Buildings 123 SyedAzizul Haq,PEng Public WorksDepartment Dhaka Bangladesh ISBN978-3-319-46360-5 ISBN978-3-319-46362-9 (eBook) DOI 10.1007/978-3-319-46362-9 LibraryofCongressControlNumber:2016954585 ©SpringerInternationalPublishingSwitzerland2017 Thisworkissubjecttocopyright.AllrightsarereservedbythePublisher,whetherthewholeorpart of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission orinformationstorageandretrieval,electronicadaptation,computersoftware,orbysimilarordissimilar methodologynowknownorhereafterdeveloped. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publicationdoesnotimply,evenintheabsenceofaspecificstatement,thatsuchnamesareexemptfrom therelevantprotectivelawsandregulationsandthereforefreeforgeneraluse. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authorsortheeditorsgiveawarranty,expressorimplied,withrespecttothematerialcontainedhereinor foranyerrorsoromissionsthatmayhavebeenmade. Printedonacid-freepaper ThisSpringerimprintispublishedbySpringerNature TheregisteredcompanyisSpringerInternationalPublishingAG Theregisteredcompanyaddressis:Gewerbestrasse11,6330Cham,Switzerland To my wife Dr. Farida Hashmat Jahan Foreword I I would offer my congratulations on the publishing of Harvesting Rainwater from Buildings. I am honored to be writing the foreword and, in my capacity as InternationalAdvisoroftheBangladeshRainwaterForumSocietyandpresidentof GroupRainDrops—whichpublishedRainwater&You—Iamveryhappythatthis vitally important concept of rainwater harvesting will be further disseminated in Bangladesh through the publication of this book. From “drain city to rain city,” from “dependence on off-site water resources to independenceonon-sitewaterresources,”andfrom“life-linetolifepoints”—This isthe“Tokyolesson.”SumidaWardinTokyosufferedfromsevereurbanflooding as well as water shortages and major earthquakes in the 20th century. We started rainwater-harvesting projects in 1982 for flood control, saving the city water sup- ply, securing emergency water, and regenerating urban-water cycles. I have been involved in rainwater-harvesting projects as chief of the Rainwater Harvesting PromotingsectionintheSumidamunicipalgovernment.Sumidatookinitiativesto promote rainwater harvesting at a public level as well as private and community levels,incooperationwithPeopleforRainwater,anNPOestablishedin1995,after the Tokyo International Rainwater Utilization Conference was held inSumida city in 1994. The Sumida Rainwater Rules were established in 2008 to promote urban development. Based on these regulations, Tokyo Sky Tree, which is the highest broadcastingtowerintheworldandwascompletedin2012,hasbecomeasymbol of climate change adaptation in Tokyo. Rainwater falling on the roof of the observation platformsat350and 450mas well astheadjacentbuildings hasbeen stocked into a basement tank with a total capacity of 2635 tons. This means that evenifthepeakrainfallof100mmfallsonTokyo,enoughrainwaterwillflowinto the rain tanks to prevent flooding. Harvested rain has been used for watering the green roof and for emergency water. Rainwater-harvesting systems havebeenintroduced into 560private houses andbuildingsinSumidaCity,andthetotalcapacityofrainwatertankshasreached 22,000 tons. Sumida City has moved from a “rain city” to a “drain city.” vii viii ForewordI Following the initiatives of Sumida City, 208 local governments set up subsidy systems for rainwater utilization and infiltration all around Japan. In addition, the Japan Rainwater Harvesting Promotion law was established in 2014. According to this law, a national guideline for rainwater harvesting was set up in 2015. It states that rainwater-harvesting systems should, in principle, be introduced into new national public buildings. In addition, the Japanese central government has rec- ommended local governments to promote rainwater harvesting all around Japan. Totryandintegratesustainablerainwaterharvestingintothefabricofsociety,in 1995 I published (in Japanese) Rainwater & You: 100 Ways to Use Rainwater.” which covers background, policy, design, and case studies of rainwater harvesting not only in Japan but also all around the world. The book was translated into nine languages and published in eight countries. The Architectural Institute of Japan publishedTechnologicalStandardsonRainwaterHarvestinginMarch2016.Itwill be useful for architects and plumbers who design and install rainwater-harvesting systems in buildings and houses. Industrial national-standard technologies and productsofrainwater-harvestingsystems,suchasthoseestablishedinGermany(as DIN [German Industrial Standard]) should be considered in order to secure low-cost, high-quality, long-life and easy-maintenance systems in the future. After themainstreamingof Japanese rainwaterharvesting in urban areas, it was good timing to publish Harvesting Rainwater from Buildings in Bangladesh. It covers basic information about rainwater harvesting such as water requirements, rainfall, roof, tank storage, water treatment, water supply, ground recharging, and drainage.Mr.Haq,theauthorofthisbook,isadditionalchiefengineerofthePublic Works Department in Bangladesh as well as president of the Bangladesh Rain Forumsociety.Heisaspecialistofplumbinginthefieldofcivilengineering,andin thisbookheproposesspecialdesignsofrainwaterstorageforbuildings.Thisbook wouldbemosthelpfulforarchitectsandplumberswhodesignandinstallrainwater harvesting systems in buildings not only in Bangladesh but also those who do so internationally. I hope that the Bangladesh government encourages introducing rainwater-harvesting systems into new buildings to solve the water crisis in mega cities such as Dhaka city, Chittagong city, and Khulna city. I’m sure that Harvesting Rainwater from Buildings can make a great contribution to develop technological national standards in Bangladesh. JapanandBangladeshareblessedwithrainandbeneaththesameskyofMonsoon Asia. Both countries have suffered from urban flood, cyclone, and water shortages. The problem is insufficient water; the solution is rainwater harvesting! I sincerely hopewecanlearnwaterlessonsfromeachotherandshareandexchangeexperiences of rainwater harvesting. I believe this book is a big step toward that goal. Shizuoka, Japan Dr. Makoto Murase, Ph.D. April 2016 Visiting Professor of Faculty of Pharmaceutical Sciences Toho University, Japan Chairman, Skywater Bangladesh Ltd. Foreword II I read the manuscript on Harvesting Rainwater from Buildings written by Syed Azizul Haq, PEng, with keen interest. Earlier in my life I taught hydrology for a number of years to the students of Civil Engineering at the Bangladesh University of Engineering and Technology (BUET) where I was a member of the faculty. Therefore, issues related to the characteristics of rainfall, the relationship between rainfallandrunoff,issuesrelatedtogroundwaterrecharge,etc.,areofinteresttome. I read the chapters on groundwater recharge, rainwater drainage, and rainwater-harvestingelementswithdueattention.Thebookintroducestheseissues inabriefbutsuccinctmanner;therefore,anyreaderwillbeabletodevelopaclear understandingofthehydrologicalcycleandtheavailabilityofrainwaterthatcanbe harvested in an economical manner for use in a building for various purposes. Bangladesh receives very high annual but limited rainfall over a period of 3–4 months each year. The average annual rainfall in Bangladesh is more than 2500 mm. It varies from 1500 mm on the western side to 10,000 mm in the northeast. However, because the rainfall is limited over the months of June through September, it has never been considered as a regular and dependable source of supply for drinking water throughout the year. Reports are available of people of the coastal belt who, in earlier days, used to storerainwaterinlargeearthenjarsforconsumptionthroughouttheyear.However, thousandofpondsandtankswereexcavatedalloverthecountrytostorerainwater to be used as drinking water over a period of one year. Harvesting rainwater from buildingsinurbanareasisanemergingconceptinourcountry.Thegovernmentis showing keen interest in adapting rainwater harvesting as an important source of water in commercial as well as residential buildings. The book very clearly describes possible options for the collection of rainwater as well as its storage and subsequentuseforvariousdomesticpurposesincludingsanitation.Thechapterson estimating the demand for water in various types of buildings—as well as how to collect, store, and process rainwater—are important sections of the book. In my view, any professional—as well as anyone interested in harvesting rain- water—will find the book to be a practical and professional guide. The book ix x ForewordII demonstrates that in a world where water is a finite resource, it is an economic as wellasenvironmentalandsocialgood;however,rainwaterisafreegoodthatmust be harvested, processed, and used appropriately. Water is one of the essential elementsforsustaininglifeandlivelihoodintheworld.Withsomeeffort,rainwater that occurs naturally can be a valuable resource that can be used for benefit for humankind and society. I am confident that the book will gain popularity among all those interested in harvesting rainwater from buildings. Dr. Ainun Nishat Professor Emeritus, Centre for Environmental and Climate Change Research, Ex-Vice Chancellor, BRAC University, Bangladesh Preface In the year 2000, the Ministry of Housing and Public Works (MoHPW) instructed the Public Works Department (PWD) to write a guideline on rainwater harvesting. Finally a booklet on rainwater harvesting was published jointly by the Public Works Department and the Department of Architecture (DoA) under the same ministry.Thebookletwasmerelyanintroductiontorainwaterharvestingfurnishing someguidelinesthatwereapplicabletosmall-dwellinghouses.Limitedknowledge and availability of information in this regard were the basic reason behind the publishing of such a booklet of rainwater-harvesting guidelines. Engineer Quamrul Islam Sidique, PEng, at that time the secretary of MoHPW, arrangedthevisitofDr.MakotoMuraseofJapan,nicknamed“Dr.Rain”andnow knownas“Dr.Skywater”(andwhowroteoneoftheforwardsforthisbook)came to Bangladesh to share his long-standing and vast experience in this area with engineersandarchitectsinthedepartmentsundertheministry.Subsequently,afew piloting initiatives of harvesting rainwater from buildings, mostly projects, were implemented at a small scale. Withtime,theoverallwatersituation,particularlythewatersupplyforcitiesand urbancenters,intermsofbothqualityandquantity,wasincreasinglybelievedtobe declining considerably. Until today, among water users, buildings of various occupanciesarethemajorconsumersandworsesufferersofthewatercrisis.Inthis situation, although rainwater harvesting was thought to be a reliable mitigating option, little heed was taken among policy makers, building regulators, and developers—inboth thepublicandprivatesectors—totake pragmaticstepsinthis perspective. In these efforts, various important issues surfaced regarding the implementationofthisconceptpredominantlyinbuildingsectors.Themajorissues were the lack of exclusive guidelines covering all of the aspects of rainwater harvesting suitable for different local conditions plus ignorance regarding plumb- ing, which plays a vital role in rainwater harvesting, particularly in buildings. Against this backdrop, with a view toward disseminating the concept of rain- waterharvesting,theunderwriterintroducedrainwatermanagementasanexclusive chapterinhisfirstendeavor,PlumbingPracticesin2006,whichappearedsimplyas an introduction to harvesting rainwater from buildings. However, to obtain xi