Large-scale irrigation agriculture formed the economic backbone of civilizations on the north coast of Peru. Contrary to the notion that large systems required the guiding hand of the state, historical sources suggest that management was largely local and segmentary. At the same time, water and land are a potential source of economic and political power for state administrators who may intervene in the supervision and management of farming. The Pampa de Chaparrí, in the Lambayeque region, is an unusually well-preserved system of canals, fields, and settlements where the dynamics of water, land and politics can be observed. Systematic survey documented a Middle Sicán (A.D. 900-1100), Late Sicán (A.D. 1100-1375), Chimú (A.D. 1375-1460) and Inka (A.D. 1460-1532) occupation. During Middle and Late Sicán, settlement patterns reflect the segmentary organization described in historical accounts. With conquest by the Chimú and Inka Empires, state administrative centers were constructed, existing social groups were reorganized and communities and households were transformed. Thus, though local management is an effective and stable strategy for managing large irrigation systems, the wealth and power that these systems represent make them potential targets for more direct state control, with significant consequences for local inhabitants.