machan this is a new location and made national park in 2002. Machan you should see the entrance. It was done in 2007 and it has some awesome buildings and a small exbit of animals,
you have to access it through rotawewa which is just near the minneriya national park but to the opposite side of the road,
any new map should carry the route,
Only problem is machan when its goverement owned they do not know how to do marketing.
Machan we went at the ideal time because its now that raining season has started. so where were is where the lake should be, its just starting to fill up. best month i would suggest you to go is either august or the begining of the dry season so that there will be loads of mud to play with.