Why the circumambulation (Pradakshinam) is restricted in the Lord Siva Temples (Sivalayas) ?

Lord Maheswara is the lords of the Devas. The Deity Ganga dwelsl  on Maheswara’s Jathajutha (plaited hair) . From the Siva’s Jathajutha, the Ganga flows on to the Himalayas and then on  to the earth. 

When we do the  coronation (Abhishekam) to the Lord Siva, the water of Ganges flows through  His pedestal which is Peetham and then  flows  from the  way arranged to the  outside.  Suppose, if we do the circumambulation (Prakashinam), we will have to  cross that water of Ganges which is Dosham (apacharam = against to the custom). And more over that sacred water which is done for the Coronation to the Lord Maheswara.  Therefore, in the temples of Lord Siva the Pradakshinam is restricted. Some devotees do the Circumambulation in the Apasavya (Anti clock wise direction)way without crossing that Abhisheka Jalam which comes out from the inner temple (Garbha gudi)  for avoiding  that Dosham.