The Groundwater Department has invited tenders for doing protection works around 50 borewells in the district, to be filed in sealed covers before 3 p.m of August 7. The sealed tenders will be opened on the same day after 3.30 p.m in the office of Deputy Director (DD) of Groundwater Department at Ramannapet here. Bid documents can be obtained from the DD office, according to an official release.