groundwater development basic concepts for expanding crs water programs pptx

Where succesful groundwater development programs have been implementl the transfer of tchnicl knowledge and best practices to ther countries ocasionally hasbeen limited by an inadequate

Groundwater Development

Basic Concepts for Expanding CRS Water Programs

Vincent W.UBL Jen A Baron Wiliam W Dav,

Dennis B.Warner and Christopher C Seremet

Basic Concepts for Expanding CRS Water Programs Vincent W UN ac A Baron, Wiliam WW, Davis

Dennis B Warner and Christopher C Seremet

Duty 2008

Ocrs

provides emergency lin the wake of natural and man-made disasters Trough development projectsin elds suchas education, peace and justice agriculture,

‘microfinance, health, HEV and AIDS, CRS work to uphold human digaty and promote better standands of living CRS also works throughout the United States

to expand the knowledge and action of Catholics nd others intrested in sues of| {ternational peace and justice, Our programs and resources respond tothe US Bishops call to live in solidarity-as one human family-across borders, over oceans,

nd trough diferences in language, culture and economic condition,

Wiliam W Dass - Constant

Dennis B Warner Senior Technic Advisor: Catholic Rel Series

Christopher C, Seromet- Technical Advisor Catholic Rei Services

Graphic design by Ephea Gea

Coverphotoby Andrew McConnal for CRS

© Copyright 2009 Catholic Relief Services—United Sates Conference of

Catholic Bishops

Published in 2009, Download ths publication and related mater at

wow crspeogramuaityorg

CONTENTS

Introduction

1.1 Gmoandiat The Biss eee

1.2 Groundwater as4 Renewable Resource

Part I: Wells and Borcholes

2.1 Selection of Wel its

2.2 Well Construction and Precio

“able 2 Service Level and Quantity of Water Collect

“Tble 3 Simple Table of Basic Survival Water Needs

ible 4 Summary of the Appropriateness of Well Construction Technolog an

Table Ding Method Selection for Difirent So Type 24

“Table 8, Compatson of Pumps

“Tble 7, Comparison of Fnengy Sores

“Tale 8 Pumping Coss

Figure A2: Geondwater

gure A: Unconfined and Confined Aquifers an fects of

Pressure

INTRODUCTION

Because of the groving importance of water inthe belt, agrlulural

ann envionmental sector, the development of groundwater sources

Isbecoming increasingly central tothe succes of integrated an?

development programs, CRS experience with and capacity to undertake

grounder development tends to be restricted by a shortage of technical

stuf Where succesful groundwater development programs have been

implementl the transfer of tchnicl knowledge and best practices

to ther countries ocasionally hasbeen limited by an inadequate

"understanding of the potential nets of groundwater within snior CRS

sulfa the regional and country level

‘The purpose ofthis technical paper isto inform CRS staff ofthe potential

for groundwvster devlopment in country programs, It is nota planning

ordesign guideline, but rather a general technical overview of aeitical,

component of water development,

“This paper explains basic groundwater and wel diling concept and

shows how they can be employed to strengthen and expand CRS water

development programs The target audience isthe CRS Program

Managers, Country Representatives and Regional Advisors who have

_esponsibiles for programs and projects involving water

‘Toenhancea getter awareness and understanding of groundwater

development, this technical paper has the following objectives:

+ To highlight the uses of groundwater in development projects

+ To show how groundwater can improve publi health expand

fod production, and support veldhoods

+ Toilustrate the principles of groundwater occurence

+ To outline the basic technologies in groundwater projects

This technical papers ad out in the following manner:

Part: Groundwater Basis

1.1 Highlights the bases of goundwater hydrology

1.2 Outlines the fragility of gmundwater asa renewable resource

kế

\dentifes advantages of using groundwater over surfice water

Introduction | ¥

VE Introduction

14 List the many uses of groundwater 1.5 Describes groundwater quality and how its determined Part Hs Wells and Boreholes

21 Outlines the siting of dug wells and boreholes

22 Describes the construction of walls 2.3 Outlines the wate of pumps, poser sources and engines Part IT: Groundwater Programming

5.1 Presets key considerations for groundvater programming Appendices

PART I: GROUNDWATER BASICS

1.1 Groundwater: The Basics

Fresh groundwater occurs a my of geologic forms, These range

fom vat regional aguier systems sich asthe Nubian Aguifer (North

Africa) andthe Oglala Aquifer (West Texas, OK

ima, Kans and [Nebrasa) which extend over milions of square miles, tolcalized river

bejn ystems and tiny freshwater lenses that accurheteon the sueace

and the scaeater beneath islands in the Pacific Ocean Groundwater

a principal source of supply for ma yvllags, towns ad les serving

domestic commetcial institutions, industrial and agricultural uses The

leigation of emps worlwide uses more groundwater (70% or geeatet)

than al other applications combined

Groundwater occur in unconsolidated and consalidated bedrock

_gologe formations, In unconsolidated formations which ae made

up of porous media gravel, sands sts and clays), the groundwater i

Hoge and eae in the pore spaces between the patil, In bedrock

formations, the water stored and travels ia jlo fissures and factures

ln the tock, refered to as secondary porosity Asa rule, groundwater

teavels very’ slowly through its geoegle mates oflen on the onder of a

few inches fet pe day The rumored presence of “undergeound rivers”

‘no more than «myth in most types of geologic stings However,

limestone “karst” formations can have systems of major solution

‘openings that comprise caveros and tunnel filled with water

Water able aquifers are unconfined systems In these aulfers, the top of

the ager isthe water tale where the waters at atmospheric pressure,

‘Walls installed ia unconfined agalfers wil sow water loves that are

gen refered toa the water table ao known asthe top of the zone of

saturation, The water table ries in response to precipitation (recharge

vents) and fallsdecines during dry periods Depending onthe aquifer

formation and topographic location, the water able can Huếtite

seasonally from afew inches to tens of fet or more under natural

conditions,

Groundwater development projects take advantage of water as it moves

through an aquifer

‘Groundwater Basics | 1

2 | Groundwater Basics

Aqui abo occur in semi-confined and confined conditions In confined (rtesan systems, the permeable aquifer i sandwiched between two relatively impermeable ayers (lay or bedrock) called the upper and lower confining units The water in the aguifr is at grestr than atmospheric pressure and a surface analogous to the water table can

be visualized above the actual agufer representing the hydraulic head, vhich edlel the piezometie surfes Walls installed in confined or artesian ase wil show water levels tat ae higher than the actual aquifer clevtion and equivalent tothe pierometrc surface In some cases, lowing artesian wel results when the pressure head within am artesian auiferis such thatthe piezometric surfice is higher than the ground

Groundwater development projects take advantage of water si moves through an aguifer Wate that is removed by humans at one place in the auife maybe eplaced by ruin that alls another region An aque

“charged” as groundwater is replenished, which serves as akind of natural

‘Pipeline rom one area to another Tis phenomenon butlers against droughts, Some aquifers are o lange that any water taken out has ite sift on the remaining water Most aquifers are ot this large, howe,

and itis posible for an aguter to hecome depleted through overpumping and othe forms of water extraction, Depletion depends om the bance

‘between hove much water staken ont and how much i replace,

‘Overesplitation of aqufersis sometimes called “mining wate 1.2 Groundwater as a Renewable Resource Groundwater development in CRS projects normally serve the neods

‘of small rural communities for domestic water, local livelihoods and

‘emergency pagposss tis essential therefore that sich project provide groundwater of afcient quantity and quality to serve the identified noo In ts simplet and most immediate form this mans thatthe instalation of wll fora project mus yield the desired quantity nd _qualty of water (wth or without tealmeat) on sustainable basi Forlangerscale projects there isto the rita question ofthe

“sustainability of the aguiferitse forall ofthe stakeholders who dra their water supply from the ager, More rsenly there has been

Increased concer and emphasis on the rol of groundwater ia sustalning

the environment and preserving the dey weather base Hows of teams

and wetlands as habitats for ecological users,

‘hea criterion fra safe and ssamable groundwater poet that

the watering abatracted des ot exceed the ager echare Ths

comparison is usaly ade onan anal asad takes ino acount

the quay of recharge during yeats of oral peipation, During

yesef drought the water supply ny rato some extent onthe amount

ofwater in sorage ta wil dates ver ie unl the quer is

repens gin in years of normal or above-normal precipitation

over an extended prod oftime, the amount of water beng pumped out ‘The basic criterion

is grater than the quantity of echare, then the water evel fhe aquifer foreealeand ill deine and wells wl evel go dey This unsound cndton

of aque depletion aly cilled mining of goundvatet’ hasbeen 3

ring problem in any purtsf the word groundwater project

is that the water

sustainable

‘The growing use of groundwater and the resultant increased demand

on limited groundwater supplies have le to mone complex problems of being abstracted suring and llocstion of stressed groundwater systems, Integrated water does not exceed the resource management or integrated river basin management (WRM/ aqiifee vechargé IRBM) approaches consis of looking tthe groundwater and surface

sear resources of watersheds over basins asa whole nan atte

te balance the limits f the renewable resource agains the needs of the

competing users

As with any natural resource, groundwater ast be developed with

‘luton and managed with ce with espect forts vulnerability and

awareness ofits imitations However, propery utilized inthe right

applications, CRS Country and Regional Managers should recognize

sroundwatsr asa powerful resurce that can create many opportunities

forlocal and regional development

‘Groundwater Bass | 3

surface water and

has a lower potential

for transmitting

disease

41 Groundwater Basics

1.3 Advantages of Groundwater Groundwater often has advantages of quality acess, and relay versace water

Groundwater is usally fee of microbiological poll

perclates fom the surface ito aquifers, sland rocks fer out ving

‘organisms, which an bea major cause of disease, Wate ean also be safely and indefinitely stored in aquifers while maintaining a igh evel

‘of guality The quality of surface water can vary seasonally and rouite

liferent disinfection processes Surface water requites closer monitoring and more extensive disinfection than groundwater,

apt to changing water conditions

Because ofits protected condition, groundwater ess ikly to

he contaminated than surface waterand has lower potent for transmitting disease, Even 11111 111111

«leveloping groundwater sources may bea beter choice to ensue the provision of uf water

Aquifers ate natural storage systems for water and, Fan agate is long enough, may be ale to provide water through dry seasons and lroughts—times when suefae water soueces ate untliable or even absent, However aquifers ary i size in how much water they can soe, and in how quickly the wate i eplenished.Ift90 much water is draen fom an squier too quickly the aque could become depleted Pump testing of individual wes is necessary to determine long:

Aquifers that underlie communities ate convenient sources of wate, People need travel only short distances to walls lea

In townsand villages instead of having to walk to distant surface water sources When

‘waters easly ailable, more oft will bused The increased use of water for drinking, cooking, bathing, washing clothes, and household

‘leaning improves hygiene and health, Sometimes ateas outside of villages are not secure and women and children may fice danger fon criminals when fetching water from distant sources Developing groundwater sources within villages helps to avoid these threats

‘Im many cases, groundwater hased water systems are les expensive

‘to install and operate than suefae water systems, mostly Because

surface water usually requires extensive teatment Installation of wells

and pumps generally require few days to af weeks, including

‘ruining ical people to operate, maintain and repair the system the

groundwater system promotes economic grosth by increasing crop

eld through irigation, fr example, a stepwise installton canbe

{mplmented with farmers building onto the original system overtime

ss their incomes increase In this way a tar-up project can be expanded

withthe profit generates

1.4 Uses of Groundwater

Groundwater is used fora wide rnge of applications, including provision

of potable drinking water for village town and urban suppl ndiutlondl

supplies: ageculuel supply for multple uses small-scale industrial use:

and emergency water supply provision fr eefagees Glabally, many major

‘ites towns, ilages, and emote communities ely on groundwater as

their primary source of water supply

Groundwater soften the only source avalale to locales that are distant

ftom surface water sources A well yield of fe gallons pe minute (less

than 02 bters per second (ps) is often suticint fra small village hand-

pump application, For towns an tes, nvidia well yields i the tens

and bundeeds of gallons per minute (1 to 103 ofp) are desi

‘The framework ofthe CRS Water Sector species four categories of water

+ Water for domestic uses to improve health, Promoting health i

primary gol of water development projects, and this goal should

bea maordeving ctr all watse supply projects isl

accepted thatthe domestic water use of water contributes to the

Improved health of households and communities

+ Water for productive uses to strengthen livelihoods The

Productive uses of water in agriculture, small industries, and

local construction contributes to strengthening the livelihoods of

rogram beneficiaries

Globally, many major cities,

supply

‘Groundwater Bass | 5

6 | Groundwater Basics

‘Water for environmental protection t sustain natural resources, Development programs should contribute tothe sustainable use of water resources inthe watershed

‘Water for emergencies and disasters to protect lives and livelihoods Programs should contribute the stabilization and restoration ofthe health and iveihoods of communities that ate unable to cope with natural or man-made disasters atfecting them, Examples illustrating the above categories of water use follow

Potable Supply for Vages GGroundvatr can be a primary water source for communities, In many pices, groundvater is the only alternative when surface water isnot availble and iste the best option even when surfice wate say able

‘The advantages of groundwater include (Groundwater can often be develope in close proximity fo oF

‘within a vilage/twn setting

“The quality of groundwater is often superior to surface water and tecatmentrequiements ae generally simpler and ls expensive,

‘stem installation costae generally ower for groundwater well systems,

Installation timeframes are markedly shorter fr groundwater well systems,

‘Operation & Maintenance (O&M) requirements ae simpler and les costly for groundwater wll ystems as compared to sources derived from surficev

Insitutions suchas hospitals nd schoo that have wellson the premises

clan and noed not depen on water vendors surface water,

orother posibly untclisble sources, wel that can provide s constant

supply of water helps to ensure contin of institutional operations, In

the absence of neathy water souree, schools often use tents to cary

water which can take a great del of tim

reduced there willbe ess ce forthe wate to gt contaminated, and

students wil have more ee time for their studies

Insitutions use their water supple or several purposes, inelaing

{rinking, cooking, landscaping and small ard irrigation,

houscheeping, small cle industry, an firefighting, Employees of the

Sinsation may use the wel wate for household use a fringe benefit of

Groundwater Bases |7

i z :

an important source of irgation water supplies Wells can provide water for small-scale ivgaton for private landholders a well as community farming Irvgaton aso can help to extend rowing seasons, protect, against drought, and increase cop yields

‘59

‘Small-Scale Industrial Use

‘Vilage-level indore, such asbrick making, textile production

dairy faring, and food pracessing ll equlre witer, Groundwater

development can providea rele supply of water fo entrepreneurs,

whlch cam help o ensure a constant pace of production and provide for

income generition,

Groundwater Bass | 9

[A hanp nd ay vate roa ate

Emergency Water Supply Development for Refugees Displaced People

In emergency situations resources are usually scarce and time for implementing rele programs limited Trucking wate to remote camps

at the onset of crisis common, but it isalso time-consuming and expensive Because groundwater systems canbe built ina shor time and are able to deliver dean water on-site, they are often the prefered method for water supply

1.5 Groundwater Quality

Physical, chemical and microbiological parameters are used to measure _groundwater quality, Physical parameters describe the colo, tempera

an amount of solids that are suspended in the water Chemical pollutants

‘may originate from natural deposits inthe solo from industrial discharges and diferent parameters exis for each pllotant source

10 | Groundwater Bases

Gainer Sap ATS ROME GARY Wa ORNS ARGU Ge Se eae ARE TF

‘Microbiological pollutants mostly come from human and animal waste,

though afeware naturally occurring, Bacteria in drinking water is

major cause of dscase and heepng a water system fre of bacteria isan

important step in protecting community health This section gives an

overview of groundwater quality sues Further information is available

fom the CRS Water Quality Manual, which provides wreater detail on the

scientific hackground of 1111111111

kits and water soure protection

Physical-Chemical Comtaminunts

There isa wide range of physical-chemial contaminants found in

groundwater, mos of which are harmless to human heath although |

1 few pose serious hazards, Physical contaminants ate judged by the

appearance, taste, and odor they impart to the water; For drinking water,

these characteristics should be aeeptable to the consumers, Water that

{scolored or cloudy due to particulate mater and disolved solids may

‘ote harmful to heath but may ase questions about the acceptability

ofthe watero the users, Taste and aor isues can he caused by

Groundwater Bass 111

‘Taste and odor

issues can be caused

<lorne disinfection process Clones canbe removed wit vari

of fitering processes

“otal disolved solids (TDS) isthe overall measure ofthe inorganic sas calcium, magnesium, potassium, sodium, bicarbonate, chlorides, and slits) dissolved in

determines whether the water may he considers fresh, brackish, oF saline A-TDS level of es than 600 mailer, for example i usually acceptable for drinking, while levels exceeding 1,000 mgr tend to

‘cause drinking water tobe to saline for normal consumption, High levels of TDS may ls cause excessive scaling in water pipes, esters boilers and household appliances

soundvate The concentration of TDS

‘becaeflly isle to depths no greater than the extent ofthe freshwater layer Saltwater intrasion/upwalling asa result of excessive pumping

‘of groundwater fom afresh water aguier undedan by salt wae, isa

‘widespread problem that as occured along many costa ares

‘Chemicals in groundwater wally come frm underground mineral {depois although instil runoff can ako be a sourcein mone developed areas Some chemicals, especialy arsenic, uoride, and nities,

‘when present high concentrations, can he harmfl to humans, Arsenic

‘concentrations in excess of World Health Organization (WHO) guidlines and national standards have been found at many locations globally

“Arsenic ean cause cancer, hyperkeratosis, and peripheral vascular disease lurid are common in volcanic ates sich asthe rif valley of east and southern Arca and elsewhere, Fluorides can cause moting of tooth anda clevated concentrations cin case skeletosis Nitrates can he ase bythe leaching of erties into shallow groundvater and fom

‘pie sstems draining to sallow groundwater particularly in town and than stings where septic systems are very dense, Nitrates cam case

‘methemoglbinemia of “blue baby syndrome” in infnts, in which the

hemoglobin inthe Blood is unsble to transport adequate amounts uf

‘oxygen throughout the body

Standatds for drinking water quality are et by atonal governments

slthough individual onganzations may establish thei ca internal

guidlines WHO publishes recommended fits for chemical

concentrations based on heath concerns sample of WHO gullins

{or some common contaminants is found in Table

Common Groundwater Contaminants

‘Contaminant Limit of human WHO guideline | Major acceptability

acceptability (taste/smell) | value or health effects otal basoWved Sods 1000 mạ NA [fiimlesmel

(703)

hyoeoss

(Cue baby syndrome)

ung cancer Fazal (Eco) bactea oy DmgjL — [Gamentetnal

istress, intestinal infections

‘Microbiological Contaminants

Many types bacteria, viruses, protozoa, worms and wher oganisns

{Mat livein water are knoe to cause disease i humans, Because few

ofthese onanism can multiply in thebody and make person i and

a contaminated water source has the potent net great numbers of

people, microbiological water quality i of paramount concern,

COngaisms tat make people sick ate clle pathogens, Because most

vaterbore pathogens come fom human and animal Feces tis important

tw hep ees ot of water supplies, The term E.coli fain bara

sn animal ees a is uses india for fea contamination

‘iter that contaminated with, cols probably lo contaminated with

tht, more harmful, pathogens thus the presence of F cll sam indicator

nga of pathogens lll texts fr E, cll measure the number of

bacteria per volume of water, WHO water quality guidelines recommend [Groundwater Bases | 13,

14 | Groundwater Basics

that drinking water contun no Ecol other fa coliforms

It shout be noted dat bacterial contamination of well fom haman snd animal wastes causes the most sigafcant impacts on human health Examples include a varety of intestinal infections inching dysentery cholera typhoid, and hepatitis,

Drinking water well nee tobe eonsteucted with sanitary proeetive seat of xen goat been the ded borehole and wel asng Tiss prevents surface contaminants especally hacer om mngrating (seeping) down the well tween the casing nd the borehole into the groundwater

[His als important that drinking water well sited at safe distances fom subsurtace wastewater disposal systems (sept systems) and ater lund uses that can impact groundwater quality Soures of plltion Include workshops fuel song and dispensing facies, garbage dumps

un landfills ageeutural products sa chemical sorage teas and areas

cf ndustry and manutacturing Principal water quality parameters, such as toa colfrm and eal coliform bacteria, iteates and total solved solids, should be

‘monitored on a outine bass, Quarterly or semi-annual monitoring is commended for fecal coliform bacteria, while fr total dissolved solids and nates, les frequent monitoring (anual of biannual i usually sulfcent, Ic acter ane found tobe present in wate source, then corrective ation shoul be implemented This could ake the frm of (2) isitecting the well with a chlorine solution and then eetesting, (b)

"egating the wellhead where wate might be seping/ntitrating nto the wall betwen the casing andthe borehole, or (c weating te water inthe home ort the wellhead

PART II: WELLS AND BOREHOLES

2.1 Selection of Well Sites

Several factors ntlence the selection proces fr the sting of well

‘The aalabilty of groundwater aquiters within or near a community

{sa factor bat just as important are community politics and Factors

nlacncing sustainability, The bew sie Fora well sone that des not

Alisrupt the social norm ofa commanity and atthe same time provides

reasonable access and safe and alicint quantities of water fo the

community members shouldbe involved at al stages of wel pla

located on public grounds dose as possible to the users, Well bul on

private property may cause problems of access and ownership between

landowners and users Wells bu to fae fom the population o

dangerous parts of town cou expose people to dangers when they fetch

wer, Because women and gis carry most ofthe water, the well shoul

beina place accessible to them and where they fel secue, The best way

to determine this to have the women participate inthe selection ofthe

wel site,

Quantity of Water Needed

Public heath in communities geal fficted by both access to water

sources and usage of water in households, WHO defines basi acces

to water tobe a less 20ers of water per person per day within one

kilometer ofthe dwelling I also recognizes that increasing the amount

ofaalable water can improve hygiene practices and reduce public health

risks in communities WHO docs nt set daly minimum quantity

‘of water per person, bu ses sliding scale tht relates the level of

service of houschold water use to public helt isk as shown in Table

2 Development agencies and communities ae advised to racognize this

‘eltionship and work to improve public heslth by increasing the quantity

of ralale water

Walls and Borehoes | 15

Service level] Distance/time | Likely volumes [intervention priority

collected NoarES More than 1 ky | very low—5 Wer Very High

more than 30- | pe person simon he lay per Hyoiene practice | Provision of basic

[compromised | service Basic consumption | Hygiene education

ay be compromised Bosc occas [MEOInIkm [Average—20 her | Mian mạn

wHØ 3f-mln — rondo (| ey lperpeson per Hygiene may be | Hygiene education

compromised Provision of improved Laundry may cur [levels of service

of plot Traemeiite | Water provided [Average—50 ier | Low Tow

cess Jonplt through | per person per asa a [ar Hygiene shoud not | Hygiene promotion wi

vandal be compromised | yield heath gaine

Laundry tkely to | Encourage optnal foceuron pit | access

[optimal acces |Suppy of water | Average 100-200 | Very Low Very Low

through murine | iters per person aps within the | per day Hyolene should not | Hyoiene promotion wi howe be compromised | yield heath gains

Laundry wi occur Jon pot

‘Sse Pawar to (05) a en WD (208), Gade Orn Naar ea, VB

16 | Wels and Boreoles

In emergency situations, The Sphere Project olden recommend that

‘each person receive an average of 15 ers of water per day (4 gllons per -đy) tobe used for drinking, cooking, and personal hygiene The Sphere guidelines rewritten for humanitarian emergencies, however and should

‘be taken ae the minimum mount of water necessary to sustain cried health and survival needs, As noted above, gester quantities of water

te ruited fr development, CRS development project that havea Arinking water component unl provide « minitnum of 20 lker/capita

ay but plan for tanger quantities when posible, Depending on climate

nd indivktualphysology The Sphere Project breaks down basi water

eds as shown in Table 3

ied Table of Basic Survival Water Needs

Water needs [Amount of water Influencing factors

Survival needs (inking water ]2.5-3 Mrs per day ‘hate and ndviduat

Bsc hyjene pachos 26 ess per day Sol and eral norms

Basic cooking weeds 3-6 ters par day Food type, socal and carat

Total basie water needs | 75-15 liters per day

‘Sas Rape fon Te Sphere Fan Waar Gare od Hmm ans WD ears Se

Fre, Gene, 20,

Wl Yields

‘The amount of water aalale fom a well depends on properties of the

aquifer and constrvetion ofthe well, amps re discussed in detail in

Section RO es important to noe thatthe maximum pumping rate fora

hand pump is 35 cubic meters of wate per hour (25 gallos per hous)

Geology

Exploring for groundater equlres sil nd experience, An in-depth

_guile on how to explore for groundwater fs beyond the scope of this

document; however, observing several hi features ofthe landscape can

help Existing walls area good indicator ofthe presence of goundwater,

(Groundwater als usualy found near surface water orn low-lying

aaa such a valleys, Some types of vegetation can also indicate the

presence of groundwater Local knowledge and scientific expertise can

both be used to determine the most likely placsto dig or dil

A variety of technologies are avaiable to asst in finding groundwater:

+ Satelite imagery

+ Aerial photography

Field sarveys of exiting wlle and springs

Finding groundwater requires skill and experience

Walls and Boreholes | 17

18 | Wels and Boreoles

4+ Ground and doven-hoe geophysics + Aguitrrechange and water balance calculations + Water level measurements and preparation of groundwater flow map

4+ Installation oftest and observation wells 4+ Aguife pumping tests

1+ Specitic capacity tests on individual walls

“The decision to use one of more groundwater exploration technologies willbe influenced by the needs of the community costs and

characteristics ofeach location

Well Upgrades

fa community is alread using wells one solution to increasing water quantities as wells quality ito simply upgrade existing wells Upgrades ray include digging the wel deeper lining the well, disinfctng it and covering it with an apron, collar an lid and installing « pump

ata Collection [Ris important to collect data on wel locations, types of oil material

‘excavated, depth othe Bottom ofthe well, depth to the atc level of

‘waterin the wll and well il, This data canbe used fo planning future groundwater projects and evaluating the impact of curen projets

Pollution Ris imperative that wells are located uphil rom sources of groundvater

«contamination such as lanes, septic ystems, damp ful stations and cil storage tanks, Wells shoul be atleast 0 meters (100) fom latrines and septic systems, and as faras possible fom fuel and chemical storage and dispensing areas,

Pek (990 Tene Boe No 8: Upgrading Tool Wek” [Adit

fom Rute epic sansa by Me Magn Ins (EA)

unin water mar ec bi th, nd baton 9 25-28

Moctoml AM, Dain $0 Daca (22 Snlematlo

ceng geome ow prs aro a, Gel

Shr Fe 201 The per Pj: hari Carter and imam

mm

2.2 Well Construction and Protection

Humans have long known the value of developing groundwater sources—

hand-dug wll date from prohstoric times and are frequently mentions

In the Bible Over 1,50 years ago well-digging technology advanced

when the Chinese developed hand:powered ding machines Drilling

rigs similar to those used bythe ancient Chinese ar in seta

Hand-Dug Welle

Hand dug wll can be constructed with nal expertise and materials

in both unconsolidated (sand and gravel) and bedrock aquifer

systems, They are a good option in areas with relatively shallow water

tables Construction i more labor ntensive and therefore more time

consuming than deiling«borchole, Lage diameter wells termed ug

re usualy dug by hand using shovels and other tools Workers

standin the bottom ofthe well an dig hile other workers al the surface

hal the loosened soil up and oat ofthe wel, Handa wells typically

range fom one to three meters (3 to 10 fet in diameter and usually

extend to depths of es than 30 meters (100 fet) deep, although some are

knoven to Be 0 meter (260 fet) deep

Walls and Borehoes | 19

Hand wels in sof sis mus be lined to preven the wal from

<olapsing Lining material can be enforced concrete rings, tones oF brick No ining need in stable soils or bedrock Digging maybe Llicult or impossible in rockyareas It isalso dificult dig deep into

an aguier by hand because once the aguiter is reached the well starts to fil with eater: Typical hand lug wel usually each only the upper part of

an aguie Fluctuation inthe water able during the dry season usually

‘cause these wel to become dey To remedy this problem, wells can be dog,

<scporin the dry uso, or the inflow watercan be continually pumped

<hring the time of construction, Care mat he taken engine driven pumpsare used to dewaterthe wel The engine exhaust must e prevented from entering the wll and casing low-oxygen conditions when workers are deepening the wal, Serious injury oreven death may occu ifthis not observed

Drilled Walls

Dried wells also calle boreholes, can be complet in unconsolidated

sand and gravel agifr systems and in bedrock aguifr systems, More

Jnormaton on aquifers an be found in Appendix C.Pactrs to take into

consideration fora drilled well construction project include proper well

siting sanitary well construction, and wel completion thats protective

ofthe wellhead

Borcholes or tube well ar typically 150 to 300 millimeters (60 12

finches) in diameter and are constructed

hand anges or engine

powered drilling rigs: Boreoles ean

be conductel more quickly and can

1g deeper than hand-dg wells, which

ables them to reach deep agile, For

hand pump installations the practical

‘maximum depth othe sate water level

{150 meter (500 fst) a pumping by

hand very ficult at his depth The

dạnh othe bottom ofthe borehole

however cam he mach deeper Borcoles

anelined with easing (PVC or see

Pipe) to prevent collapsing swell as

to prevent surface water from entering

the well, well screen is installed the

level of the witer-earing materials to

alow groundwater to enter the borehole

Wel Protection

Willsare easy routes for surface

pollution to enter into groundwater

snd care must be taken to ensure this

used for

des not happen All wel

providing water fr consumption

shouldbe covered and equipped with

‘pump Open wells should only be

used for watering gardens and snimal

and industrial uses, A cover om the well

prevents dir, drainage water, or ther

forms of pollution from entering and

Wels and Borehoes | 21

——————

Many hand dog wells ate vulnerable to contamination because they

ae constructed without coverand a pump People commonly lower buckets or other contance by ope into open wells to deaw water Tis method greatly increases the chance of well contamination because buckets and ropes usually come into contact withthe ground during, handling an storage Boreholes are typically ited with a pumping system that can be powered bya varity of methols—hand, diesel 38 cleetddy vìnl or la These same types of pumping ystems can be

‘nae in a properly designe and constructed hand-dug wll

Protective measures for horcholes are generly the same as with dag

wells The well should be sited away fom sources of groundwater

contamination and the wellhead and platform shouldbe constructed to

prevent surface contamination from entering the well and to provide a

well-drained and hygienic ar forthe community to collet wate

‘lls should he disinfected with chlorine after construction and on &

gular basis thereafter

Community education is very important o prevent contamination of

the well byensusing that the well and pumping system ar properly

‘maintained, the apron is kept clean, and wastewater is propery drained

Additional information or constructing operating, nd msitsining

hand-dug wells and boreholes canbe found in the CRS Water Supply and

Suntation Technical Reference Library DVD

Wills and Borehoes | 23

‘eltvelypletifl However, there are many documented springs in aid landscapes, fr example at desert oases, In mountainous aess springs

‘oflen can be developed as gravity stem, thus aviing the need for

ins, and where nữngdlíc

pemping oquipment Springs also can appear when an overlying layer

‘of consolidated material (ock) eeates significant presse that forces the groundwater to the surface where i forms an artesian well The rate at hich water lows fom a spring depends onthe amount of water in the

‘uifer andthe amount of pressure being applied by the weight ofthe consolidated material, This low may vary seasonally

Springs nce only minor development to hecome good w cause water lows freely from a spring, pumping mechanisms are ssualy not needed, The prospects fr sustainability are usually etter It pumping systems which generally reqite skilled maintenance, can be avoided

‘The biggest threat spring water quality i from contamination by humans and animals C

aminants especialy feces, can wash into

‘the spring and introdacedscase-catsng organisms inthe wate In|

‘order to prevent contamination, springs canbe protected by building an endosurs termed a "spring box” around the spring tats ited with am

‘ute pipe: The area surrounding the spring shold be Fenced o ep humans and animals from contaminating or damaging it A drainage

ch to protec the spring fom rainwater rapo should be dg around {he spring outside the ence The atea wher the community draws water should havea clean pron and proper drainage fr wastewater,

lumpre C2008) “aldngFeneeent Spring Box” Biman Cathe

‘tern to Seige rin aa f Appi ede Water

Aan a a Sg a Say rte wet FN ear PEP

26 | Wels and Borcholes

Borehole DilingTehnigues Several diferent dillng techniques canbe used to install boreholes The

"be technique Fr any specific sitastion f determined by sil type Percussion dling was one of the easiest dling techniques developed Adil bit isattached to a cable or shaft ehich is aise by a winch

an allowed t fill nto the horchole This proces repeated and the bit sol cisls its way into the gmund, The bit mast he withdranen peoically inorder that loose oil and rock chips canbe removed from the hoe witha hailer (backs), This press alo calle eabletook drilling

Auger or rotary ding uses Ari bi that tors ast plunges oven through the si, Soi ani chips of ck are brought to the surface by the dil bit and shat, Rotary percussion dri uses

rl through rock another hand materi,

[Ni water or md sey are sometimes ad the drill shaft

te enol snd Iubrcate the dll it

te help the bit break up soi and

te carry the soil othe surf The slurry can be ade theowgh a hollow dellshaft and pumped oat the hoe or sent dove the hole and pumped back out the shaft, This proces called jetingsadging

or slshing

Just as diferent styles of dling ae appropriate for diferent sol types,

ferent dil blts can be wed onthe same dil fo diferent ypes of ol

Experienced dil operators will know which driling method and dil bit

to use in diferent soil and rock materi

ailing techniques suitable fr use in vatiousgeologi conditions are

‘Mentited in Table 4, The resource inputs and performance outputs of

ferent well construction techologle are summarized in Table 5

conan US

Trang reir

Sa daar wale

age dente wae

lamsen

Sars spn Fon Wr, 7 G50), lng Ponto anapunp Waring Poa ne Sapa veers Santen

Walls and Boreholes | 27

‘Metamorphic | formations: ‘No No OK: ¥ slow No 0K No

28 | Wels and Borehole

Power Sources for Drills

Well-diling igs an be powered by physical bor or by machines

Deep well especially those over 100 meters (30 fet), are always

riled with machine-deven sigs, Hand ding may use human or

animal power and wualy requires more ime than machine lừng

Machine delle well, however, eure costly driling sipmtent and

‘energy sources (diesel or gasoline) snd may not be the hes option in

villages with relatively shallow groundwater tables and plentil supplies

‘oflaboe Engne-poweted delling gs can cost from $100,000 9 over

$1,000.00, depending on the capacity of the equipment Hand- or

snlmal-powered equipment costs faction ofthis total and often can

be locally manufactured,

‘One major benefit fusing local abort dil well ithe need to

‘generate signican! participation of the community a al phases of

the project This involvement helps the community develop a sense of

‘ownership toward the resulting faclity Once established, this sense of

‘wmership provides base for long-term maintenance and sustainability

‘ofthe wal

Borehole Development

‘Once a borehole dled and water i found, several steps must be

taken t develop the well These includea determination that the

amount of roundwate i suilet for the neds ofthe community and

that adequate measures have een taken to prevent the collapse ofthe

borehole and to improve the water fw from the gu,

Derenwivive Tae pRoven Depru, Once waters found the Ho ate

should be measured and, finsufclen the vel shouldbe deepened

unt the deste hw rate facleved The well then shouldbe drilled

up tan addtional 10 meters (33 fet to account fr seasonal variances

Inthe water tbl, Dring time costs money and dling wells

unnecessarily deep can be wasteful

_Measvnave waren row Its important that wate from an agifer

flows into a borchole trate that is sifcen to serve the community’

water needs, A pumping testi conducted to measure tis rae The

hw ate determined by pumping te water at a high rate ntl the

_groundwster table stops declining nd remains sable "The ow rate fs

‘One major benefit of using local labor to drill a well is the need

to generate significant participation of the community at all phases of the project

Walls and Borehoes | 2

30 | Wels and Borehole

calculated by dividing the volume of water pumped bythe pumping tne Deveronixe rn nonznors, Wate should be overpamped fem the borehole for 2 to 24 hours, This procedute creates pid ow through the aguer and into the borehole tha removes soil and sediment fom the

‘gion immedistly surrounding the pump intake, Sometimes gravel ded to the bottom ofthe ole to aid the How of water and t help filer

1 A pipe or tube, called casing typically # to 12 inches in dlmeter i {need inthe botehoe to kaep it fom collapsing The bottom section ofthe pipe has sreen, which x petorated with holes or slots tallow rater to enter the well

2.3 Pumps and Power Systems

Traionally a container, sch as an animal skin bag or bucket ited to.ampe and lied by hand or windlass o extract water from a well, Because it roquires an uncovered vl the bucket and rope sytem makes the well vulnerable to contamination, This method iso inticint and time consuming, especialy with deep wells: Pumps which are mechanical devices for iting ater, can supply greater quates of water than tational bucket ystems and enable wells oe sealed of from

‘outside contamination

All pumping systems have tivo main components—the pump andthe power suppl The pump is what physically lits the water eile the Power supply provides energy o operate the pump Pumps move water

‘ther by eeating sition ina pipe that draws water up the well ory iting the watee trough force applied othe pipe tthe bottom ofthe well Becase of the limitations of atmospheric pressure, sition pumps

‘an operate to maimmum depths of only 6 1 meters (20-25 8), Beyond this dep, i pumps mast be wsed A schematic draeing of it pump

with eyinder and piston manually powered by hand, called the

Indl Mark 1 handpuonp is showa in Figure

‘The power supply to ceitethe suction orto physical ithe water

«ane provided manually by humans or anils oi can he converted from decry solar energy gravty (Elling wate), wlad, othe heat

of combustion of hydrocatbons, Hand-operated pumps ate the most common manwal pumpsand can fatio to well depths of up to 30 meters (065 et) Eletie-ordesel- powered pumps are the most common pumps used for deep wal

Several types of pumps and power systems pÏedly seed in CRS water project ae discussed ext