COMPONENTS & BENEFITS of

PROPERLY CONSTRUCTED

WELLS

STEVE SCHNEIDER – BSME, MGWC

2011, 2012, 2013 President – National Ground Water Research & Educational Foundation

Figure 1 – Hydrologic Cycle pg.3

Non-Porous Earth and Confining Rock

Fresh Ground Water Zone Ocean

Water Vapor

Rain

Snow

Hail

HYDROLOGIC CYCLE

Septic

System

Salty/Brackish

Water Zone

Water

Well

Soil/Porous Earth

Infiltration &

Percolation

Sun’s Heat

Causes Evaporation

WATER: Same amount

yesterday, today & tomorrow

ROLE OF GROUNDWATER

World’s most extracted raw material (600 to 700 billion m3/year).

Less than 1% of all water is liquid freshwater (not ice).

Fresh liquid: >100X SW

Fresh GW:

>99% of all liquid freshwater

WHY WELL GUIDELINES?

‘WHY PROPER WELL CONSTRUCTION?’

“... in Bangladesh, …half of the countries 12 million … wells have unacceptable levels of arsenic due to the wells not being dug deep enough...” Wikipedia

- - - - - - -

“It is not enough to drill a well and walk away,” says … Jamie Skinner of the London-based International Institute for Environment and Development. … He estimates $300 million of investment has been wasted, …

“In the Menaka region of Mali, 80% of wells are dysfunctional,” …“In northern Ghana, 58% require repair.” Key problems, he says, are bad design and poor construction. ….” NewScientist.com article dated 7/14/2009

WHY… cont.

‘Hand dug or excavated wells pose significant concern for the safety of those constructing, maintaining and using such wells.

In addition, the difficulty of constructing and maintaining a sanitary supply using the dug well technique argue against the practice…’

EVOLUTION of GUIDELINES

2008 NGWA DCIG presentations

2009-10 1st, 2nd, 3rd drafts

◦ Panama, WaTER, NOLA, AWRA, LV, email etc

◦ Circulated to 1000’s; 100’s of suggestions included

2011 4th draft & First Edition @ WaTER

2012 Second Edition – CBA added. EWB regional conference @ Cal Poly

2013 Swahili translation ½ day workshop @ WEDC – Kenya

KNOWN GUIDELINE USES Course text –

◦ US universities / academia

◦ International academia (latest in Afganistan)

Other International uses

◦ Field crews – Drillers/Hydrogeologists

◦ NGOs

◦ Government regulatory agencies (create stds)

◦ Government aid agencies

Reference resource

◦ WEDC - UK

◦ RWSN - Swiss

COMING SOON

Third & ??? editions ◦ Filter pack selection and design

◦ Well design considerations

◦ Shale trap application

◦ Drilling method comparison

◦ Sealant selection / application

Translations ◦ French

◦ Spanish

◦ Chinese

◦ Dari

Workshops?

SOME COMPONENTS

Location, location, location ◦ Set backs

Documentation – well logs ◦ Facilitates O&M

◦ Used by drillers, hydrogeologists Locate other well locations

Design other wells

Facilitate drilling plans for other wells

Aquifer characterization

Reposited & accessible

Annular seal ◦ Mandatory

◦ Chip bentonite

◦ Commingling

COMMINGLING EXAMPLES

BENEFITS–PROMPTED BY BIG Q

Shouldn’t a well be constructed asap, even if resources aren’t available to properly build it, in order to get some immediate result e.g. lives saved?

Related concept: Wells should be constructed today even knowing that the resultant water supply has a high probability of containing a pathogen or harmful chemical or of wasting or contaminating groundwater?

or…

Will more people’s lives be compromised with inferior construction? Water quality, longevity of usefulness and safety are all factors.

e.g. If safety incident happens on your watch, will you be able to forgive yourself?

RISKS / THOUGHTS re: BIG Qs

Inferior wells require decommissioning or repair at some time in future: ◦ $$$ to properly decommission / repair

◦ Safety (open boreholes)

Contamination from GW creates negative perception of GW source ◦ One chance to make first impression

Long term aquifer damage ◦ GW becomes a problem, not a solution

Short term solutions are available ◦ e.g. pots

COST BENEFIT ANALYSIS

June 2012 – OSU

Jaynie Whinnery, BSME

October 2012

PDF on web – also spreadsheet

CBA SUMMARY TABLE J. Whinnery 2012

CBA Revelations

Almost 40x more benefit than cost

◦ If properly constructed, operated, maintained

~5X increase in net value with O&M

Unacceptable: Building wells that will

likely produce localized poor water

quality – negative NPV (B:C ratio <1)

3x to infinity more NPV: Proper well v

Inferior well

CBA Presumption (not specifically analyzed)

UNACCEPTABLE: Well that results in GW

contamination or aquifer damage - e.g.:

◦ Commingling

◦ Uncontrolled artesian

NEGATIVE IMPACTS:

◦ Reduced large-scale benefits

◦ Added cost of remediation / mitigation

Such impacts will most certainly result in negative NPV

CBA – Customizable Spreadsheet

Number of wells

Number of users per well

Construction costs

Discount rate

Percent of income used for water

Local GNI-PPP

Morbidity value

Mortality value

GUIDELINE, CBA, SPREADSHEET www.seidc.com/pdf/Hydrophilanthropy_Well_Guidelines.pdf