The Rejoso Watershed, located in Pasuruan District, East Java, Indonesia, is facing the issue of the depletion of its groundwater resource at least since 2007. The cause is related to the high number of improper drilled self-flowing wells. These low-cost wells are funded by the local communities and are mostly used for agricultural needs (paddy field, annual crops and livestock).
These improperly drilled wells are not grouted, nor screened. As a consequence of no grouting, they lose lots of groundwater without any use, as (i) they leak through their annulus, and (ii) they flow year/day long, also when water is not used. In fact, their owner fears that valving them will reduce their productivity. This fear is partly grounded as annulus leaks may increase following valving. Moreover, due to the absence of a screen, well also collapse and their lifespan is reduced.
In this paper the methodology developed to implement and educate both drillers and community is presented on how to drill a proper artesian well called a "good water well" that can be controlled instead of making "bad wells" flowing about 5 litres/sec for 24/7, that have been spread around 600 units in the aquifer.
The methodology is 3 steps: (i) Drilling process, divided into drilling method, well construction, and grouting. During drilling, a hydrogeological log is elaborated from cuttings description and discharge measurements to locate the aquifer(s) and design the well. (ii) Wellhead construction design: the wellhead is equipped with an efficient valve to enable closing the well when water is not needed. (iii) Educating the local community, government, and private sector, through the implementation of the "Good water well", to the differences between "good" and "bad wells".
This initiative successfully completed a pilot good well flowing 7 litres/sec and closed the bad well nearby with grouting. The log showed that the shallow unconfined aquifer extends down to 60 m. The confined aquifer ranges from 60 to 65 m (bottom of the well). A blind 4" PVC pipe was installed in the 8" borehole (0–60 m) and the confined aquifer was screened. The annulus of the casing from 0–60 m was grouted and the artesian flow stopped in the annulus during the grouting process. To control the wells discharge and ensure monitoring, a flow meter, a gate valve, and a ball valve were installed. A transparent acrylic pipe was also installed to convince local water users that the water is not "disappearing" when the valve of the well is closed and that the well will not collapse, as the community believed. This good water well manages to save water and change the mind-set of the community, resulting in 150 ML/year saved groundwater.
Keywords: drilling, sustainability, artesian management