Decision-support for arsenic- and salt-mitigation in Bangladesh: the ASTRA approach

Gábor L. Szántó, D. van Halem, L.C. Rietveld, S. Olivero, A. Adams, D.C. Roy, J. Barendse, K. Baby, M. Hoque, J.W. Dogger

Bangladeshi water crisis

Drivers of the water challenge A high population density (~1,000 p.km-1)

combined with widespread poverty

Pathogenic contamination of the surface water bodies

Arsenic contamination of the shallow aquifers

High salinity in the coastal areas

Unbalanced distribution of precipitation

(Over)abstraction of main rivers

Source: www.bgs.ac.uk

ASTRA-Bangladesh

What is ASTRA-Bangladesh? Aiding Sustainable Water Technology Realization in Arsenic- and Salt-

contaminated Areas of Bangladesh

BRAC WASH II

Objectives Assessment of low-cost, appropriate water supply technologies (both

from and outside Bangladesh) for the mitigation of arsenic and salt problems

Multidisciplinary evaluation of the applicability of the best (pro-poor; rural) methods in diverse Bangladeshi settings

Scope of the project

Potentially applicable methods from Best practice technologies involved in current arsenic- and salt-mitigation

in Bangladesh,

Sustainably applied mitigation technologies in the international, developing-context,

High-tech methods that can be potentially relevant for Bangladeshi arsenic, and

Promising arsenic- and salt-removing drinking water methods that can become potentially relevant for Bangladesh in the foreseeable future.

Intended use(rs)

Decision-makers (water experts) Advises on relevant method information

Supports formulation of an approach, a policy or a specific project

Project stakeholders (donors, users, experts, service providers) Advises a joint decision-making process

Support objectivity in a multistakeholder setting

Education (students, trainees) Offers a peer reviewed knowledge base

Supports capacity building

The ASTRA approachCONTEXT ANALYSIS (SITUATION ASSESSMENT)

NATURAL CONTEXT FACTORS HUMAN CONTEXT FACTORSTECHNICAL CONTEXT FACTORS

SELECTION OF APPROACH

WATER SOURCE ASSESSMENT

ARSENIC- AND SALT-FREE GROUNDWATER

ARSENIC/SALT REMOVAL FROM GROUNDWATER

NON-GROUNDWATER SOLUTIONS

MATCHING CONTEXT AND ELIGIBILITY

ASTRA ELIGIBILITY SCREENING

Natural context

Situation criteria Included options Signified aspect

Water source Surface, brackish, rain- and groundwater

Locality of water body

Removal Arsenic, salt Arsenic or salt

Ground formation Sand and gravel, clay formations, compacted formations, soft weathered rock and bedrock

Soil composition

Water lifting 0-8, 8-15, 15-40 and >40 m Depth of water level

Flood danger Not affected, only flooded in extreme weather & annually affected by floods

Level of flood risk

Human contextSituation criteria Included options Signified aspect Location Densely populated urban; densely

populated, low-income urban; moderately populated urban, peri-urban, rural and rural, remote

Settlement type and population density

Site selection Settlement, agricultural and coastal Type of locationScale of implementation Household, shared, small community,

school or institution and large user group

Scale of sustainable dissemination

Preferred level of water delivery

Household, shared, small community, school or institution and large user group

Connection level to water supply

Preferred management level

Household, shared, small community, school or institution and large user group

Type and level of method managing

Energy available None, electricity grid, fuel generated, solar and wind energy

Possible means of powering device

Access to site On parcel, outside of household area, <10 minutes to access, <30 minutes to access and >30 minutes to access

Means of accessibility to water point

Technical contextSituation criteria Included options Signified aspect Status in Bangladesh Widespread, known, little known and

unknownLevel of embeddedness

System sophistication Labor-intensive, intermediate and technology-intensive

Labor-using or automated process

Water transport Manual, animal, small- an large-scale motorized

Water transport options

Construction costs Negligible, <USD25, USD25-100, USD100-1,000 and >USD1,000

Costs of physical installation

Maintenance costs Negligible, <USD5 per month, USD5-100 per month and >USD100 per month

Costs related to O&M

Construction time Insignificant, a day, several days to a week and weeks

Typical duration of constructing

Level of expertise in O&M Household, local technician, local government and external experts

Required level of skills in O&M

User acceptance No activity required, limited extension, considerable extension and extensive campaign required

Level of requirement to inform user about method (implementation)

Method or chain?

The compendium

Testing phase

2 workshops and a 2-phase reviewing round 30+ medior- or senior-level Bangladeshi water experts

20 international water experts

Internal & external reviews: 10+ scientific experts

Testing workshops evaluated Quality of the ASTRA approach and value of the tool to support

sustainability in the Bangladeshi water sector

Quality of the selected pool of methods

Quality of the selection criteria

Evaluation - Approach General opinion of the ASTRA score: Good (3.91±0.74) Strengths:

Easy to define selection criteria

Relevant options are easy to identify

Quick and simple first impression of available pool of methods

Easy to browse for specific information on methods

Bangladeshi track record supports connecting with other local experts

Weaknesses: Information on practical functioning of methods is sometimes lacking

Limited use if location has a complicated setting (many selection criteria; too few options)

Application by non-experts necessitates an elaborate manual on proper use

‘New’ methods

Evaluation - Content Evaluation of the compendium:

Pool of methods is accepted as relevant (3.7±0.67)

Boiling suggested as extra method

Most popular approach: contamination –free groundwater abstraction

Most popular methods: deep tube wells (4.0±1.18), piped water systems (3.91±0.83) and rainwater harvesting methods (3.75±0.75)

Especially treatment and surface water methods are distrusted (riverbank filtration is least popular (2.64±1.03)!)

Evaluation of selection criteria: 16 out of the 20 criteria were evaluated above 3.5

Only ‘Access to site’ and ‘Water transport’ are removed from the criteria list

Conclusions

ASTRA approach can contribute to increased objectivity in water method selection Efficient provision of initial information to

project partners improved cooperation of partners in the

selection of sustainable method(s)

Transparent decision-support to keep process simple and reliable

Even with regular updating, tool reliesheavily on the availability and quality of data on method functioning

Tool users remain responsible for finaldecision!

Thank you for your attention!

The online ASTRA-Bangladesh tool is available for testing and use at

www.astradst.info