In general, the penstock is mostly aligned and designed for overburden foundation, thus the anchor blocks and the ring girders have to negotiate the overburden material. The alignment is also crossed by two perennial drainages, viz., Ghatti Khola between AB-8 and AB9, and Thotney Khola between AB-12 and AB-13. The natural drainage of the Ghatti Khola is comparatively narrower with low discharge, whereas that of Thotney Khola natural drainage is comparatively wider with high discharge. Both these drainages alongwith the seepage of HRT has been routed through a concrete drain running parallel to the penstock alignment.

• The anchor blocks are mainly placed in overburden foundation excepting the lower few anchor blocks. The penstock alignment has been feebly investigated and limited geological information is available for the complete alignment. For the better assessment of the alignment, geological information in the form of geological maps and sections are required. Due to the recent movements of the ground mass from valve house area till anchor block AB-5, this information has become much critical to tackle the problem. As an initial preventive and preparatory activity, the site has been advised to initiate a fresh topographical survey along the complete alignment of penstock. It is also advised to mark and monitor the existing ground cracks as well as the anchor block structures on daily basis using total station

• The embedded depth and lateral cover for anchor block seems to be insufficient. It is recommended to provide topographical survey along penstock alignment and cross sections at anchor block locations, so that actual position of embedded depth and lateral cover can be seen.
• As informed by the site personals, some movements have taken place for anchor block. The expansion joins bolts were seen broken, which confirm the movement. Hence, some stability measures for surface penstock need to be proposed.
• The ring girder supports were not complete . At many locations, just reinforcement cage of ring girder was installed and at many locations, the plate was exposed.
• Currently, seepage discharge from Adit-2 is being drained through drainage trench aligned along penstock . At many locations there are cracks in this drainage trench and water is seeping into foundation of anchor blocks and ring girders and causing settlement of foundation soil due to extraction of fines. It is recommended to provide separate drainage arrangement away from the penstock slope for draining of seepage water through Adit-2.
• The movement of few anchor blocks seems to be result of excavation for project access road without any adequate protection works.
• The width of Thotney Khola between AB-12 & AB-13 seems higher, to carry penstock through ring girder and find suitable foundation for ring girder . It is recommended to carry penstock pipe over steel truss bridge at this nala location between AB-12 & AB-13.
• The road crossing portion of surface penstock embedded in concrete is having adequate lateral cover on hill side, but it is exposed on toe side. The protection works need to be proposed on toe side.