Not sure about the exact thrust of your question but a few points:
- flood management is not easy to monetize so there is not much incentive for private industry. The timelines for design decisions (100 year, 500 year) often don’t mate well with private incentives
- it crosses many property boundaries which makes it hard to manage unless you have the rights of a government
- much of the work is still done by private companies but managed by the government, just like other infrastructure works like roads, bridges etc.
Flood management in the Netherlands even influenced the country's style of government decision-making: the "Polder Model" of consensus-building.
The idea is that if everyone shares the same dikes and drainage systems, they have to cooperate regardless of political differences. A flood doesn't care whose land it is.
>The polder model (Dutch: poldermodel) is a method of consensus decision-making, based on the Dutch version of consensus-based economic and social policymaking in the 1980s and 1990s. It gets its name from the Dutch word (polder) for tracts of land enclosed by dikes.
>The Maeslantkering 'Maeslant barrier' is a storm surge barrier on the Nieuwe Waterweg, in South Holland, Netherlands. It was constructed from 1991 to 1997. As part of the Delta Works, the barrier responds to water level predictions calculated by a centralized computer system called BOS. It automatically closes when Rotterdam, especially the Port of Rotterdam, is threatened with flooding.
>The Delta Works (Dutch: Deltawerken) is a series of construction projects in the southwest of the Netherlands to protect a large area of land around the Rhine–Meuse–Scheldt delta from the sea. Constructed between 1954 and 1997, the works consist of dams, sluices, locks, dykes, levees, and storm surge barriers located in the provinces of South Holland and Zeeland.
- flood management is not easy to monetize so there is not much incentive for private industry. The timelines for design decisions (100 year, 500 year) often don’t mate well with private incentives
- it crosses many property boundaries which makes it hard to manage unless you have the rights of a government
- much of the work is still done by private companies but managed by the government, just like other infrastructure works like roads, bridges etc.