Harvesting Rainwater from Buildings

282 Pages·2017·6.86 MB·English

by  Syed Azizul Haq, PEng (auth.)

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
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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.”
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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
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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
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