This chapter examines the traditional land and water management practices of Sri Lanka’s unique hydraulic civilization, focusing on their historical context and relevance to modern water governance in the context of climate adaptation. Key discussion areas include the construction of ancient tanks, water resource development under the monarchic system, water conservation through hydro-ecological techniques, land and water sharing practices, irrigation traditions, enforcement mechanisms for water misuse, and the sustainable use of natural resources within tank cascade systems. Particular emphasis is given to the maintenance and management of irrigation tanks as part of tank cascade systems (TCSs); to sustainable cascade management through systems such as Kulu Wewa and Olagam Wewa; and to land governance through traditional frameworks like the Bethma system and the Purana Wela–Akkara Wela system. These practices are key elements of effective water management and governance in the face of climate variability. In addition to these technical systems, the chapter also highlights hydro-ecological aspects such as cascade niches and traditional water control methods implemented by farmer organizations.