The REACH Khulna Tubewell Audit involved mapping of all public and private tubewells (or handpumps) in Polder 29, one of the 139 polders (embanked islands) in southwestern coastal Bangladesh. Polder 29 has a land area of 80 km2 and covers five unions (Tier-4 administrative boundary) across Dumuria and Batiaghata upazilas (sub-districts) of Khulna district. The polder is further sub-divided into 77 mouzas (Tier-5 administrative boundary), with a total population of 58,000 and 17,000 households (BBS, 2011). The audit covered 3159 tubewells mapped in two phases. Phase 1 (Dec 2017 to Feb 2018) involved a census of 2805 tubewells in the southern half of the polder, while Phase 2 (May 2018) involved a sample of 354 tubewells in the northern half where groundwater salinity is relatively lower than the southern part. The audit collected information on the location, installation date, technical specifications, ownership, maintenance, and usage patterns of tubewells. Water salinity was measured for all functional tubewells using an Ohaus ST300CG Portable Conductivity Meter, 0–199.9 mS/cm.REACH (www.reachwater.org.uk) is a nine-year global research programme (2015 - 24) to improve water security for 10 million poor people in Asia and Africa. REACH is led by the University of Oxford with an international consortium of partners and funded by the Foreign Commonwealth and Development Office (FCDO). REACH research focuses on eight observatories across three countries (Bangladesh, Ethiopia and Kenya).
The audit was administered in Bangla through an electronic form developed in ONA (https://ona.io/), and was conducted by four local enumerators, who were trained and supervised by researchers from the Bangladesh University of Engineering and Technology (BUET). During Phase 1, enumerators walked through their designated villages, visiting every household, school, mosque, health centre and market places to ensure that all tubewells were recorded. In Phase 2, where a sample of households were selected from the REACH Household Survey, enumerators contacted the owners via phone to locate the tubewells. Since the Phase 2 area, that is, the northern half of Polder 29, has relatively lower salinity and therefore a higher tubewell density, a sample audit was conducted instead of a census due to budget restrictions. The tubewell owner or manager was the respondent in most cases; however, where owners were absent, knowledgeable user(s) responded to the audit. Water samples were collected in clean, labelled plastic bottles and later transported to BUET laboratory in Dhaka for testing the electrical conductivity. All forms submitted through ONA were checked by BUET researchers daily to resolve data queries. If accurate GPS readings could not be captured due to poor weather conditions or technical issues, enumerators revisited the tubewells at a later date.
