Furthermore, there is strong path dependency arising from the history of the sector and from previous policy reform attempts. Decisions are often irreversible, some policy and production choices cannot be undone once made (ibid.). The advantage of this approach to review past policies is that it emphasises the role of interactions across actors and institutions, thereby providing a realistic depiction of decision-making. Yet, at the same time, the approach makes it harder to draw cross-reform conclusions, as it focuses on specific institutional features of the country, region or policy, without considering changes in others. There is evidence that water and agriculture reforms are influenced by pressure group competition. For instance, discussions around the management of the increasingly saline Sacramento-San Joaquin Delta in California have opposed groups representing environmental interests to groups using upstream watercourses for irrigation.