[4] Lake Disappear lies in a valley dammed by a lava flow (similar to the one which also formed Bridal Veil waterfall - see map below) and drained through a limestone sinkhole.

During times of prolonged heavy rain, water backs up behind the outlet to form a sizable lake over what are normally dry alluvial flats.”[6] Elgood Limestone (an outcrop is in the photo - see Gallery - to the left) is part of the Glen Massey Formation.

The geology guide[6] describes it as, “forming prominent bluffs or surface outcrops displaying solution channels, lapiez, and sinkholes, and is everywhere a light grey, flaggy limestone containing up to 95% CaCO3.

About its late Whaingaroan (about 27 million years ago) creation, it says, “The change from estuarine, shallow brackish water conditions (Mangakotuku Formation), to fully marine, open sea, aerobic conditions (Glen Massey Formation) is evidenced by near shore accumulation of the bioclastic Elgood Limestone, onlap of the succeeding Dunphail Siltstone, and subsequent deposition of Ahirau Sandstone in an inner to mid shelf environment.” Pakihi is a Māori term now commonly used to describe poorly drained, infertile land.

[8] A survey for the windfarm described the Pakihi, 2 km up from the Lake (site PR2), as having poor to moderate ecological health, indicated by significant growths of long-green filamentous algae.