Abyustat: Irrigator of the Maori

According to Wikipedia.org article on the Taniwha:

The Taniwah are beings that live in deep pools in rivers, dark caves, or in the sea, especially in places with dangerous currents or deceptive breakers. Some can tunnel through the earth, uprooting trees in the process. Some taniwha are credited with creating harbours by carving out a channel to the ocean.

Abyustat is a Maori tribesman who is last in a long line of Taniwah trainers. These trainers are used to irrigate their native lands of New Zealand by using their creatures to dig trenches and rivers through the dirt. My idea for the Taniwah is that it would consume dirt and is able to create water from it. It particularly fancies a special blue shell, to which Abyustat uses like a treat to lead the creature. His equipment consists of a training rod, a treat chain, a climbing crook, and devices to catch the crustaceans that live in the special blue shell.