On the night of January 31, 1953, sea water, driven by a North Sea storm and spring tide, burst through the coastal defences in southwest Holland, killing over 1,800 people and flooding over 200,000 hectares. The government's response to this national disaster was a program of dike building that blocked off three of the four major estuaries that form the mouth of the Rhine-Meuse-Scheldt Delta.
The two most northern estuaries were closed off in the 1970s turning them into freshwater lakes. But in response to growing environmental concerns, the 9-km long storm surge barrier across the East Scheldt was made up of 62 sluice gates to allow tidal flows. They are only closed if the water level is dangerously high, which has happened 25 times since the barrier was complete in 1986 or about once a year.
The East Scheldt storm surge barrier, which took 10 years and cost €5.5 billion to build, and costs €19 million a year to maintain, is a miracle of modern engineering. But when I visited the barrier in May and had a chance to ask the manager whether, knowing then what we know now about the costs and benefits of such massive structures, it would have been built, he answered probably not.
This visit was part of a seminar on strategic delta planning organized by UNESCO-IHE, the Institute for Water Education, in Delft with participants from The Netherlands, Bangladesh, and Vietnam. A delta is basically a large wetland in which all its components are interconnected by flows of water and sediment. If you disturb or change these flows, it often has unintended outcomes, creating new problems. Hence the growing interest in strategic delta planning.
The Mekong Delta is particularly complex because of its 4-meter tidal range, highly seasonal flow, and changing monsoonal winds and currents. A major unintened outcome here was, starting in about 2000, the construction of high dikes to allow a third crop of rice to be grown. A recent study shows that on economic, environmental, and social grounds this was a bad idea (http://www.eepsea.org/pub/rr/2015-RR11_Tong_digital_final.pdf).
Because the high dikes in the Mekong Delta block the delivery of nutrient-rich sediment, and three crops a year mean no fallow periods, farmers have to use more and more fertilizer and pesticide to maintain production, so their costs have gone up and profits down. Because the dikes block fish migration and recruitment, capture fisheries are declining, and because they have shrunk the floodplain, urban areas downstream are increasingly flood-prone. Because farmers have to pay for dike maintenance even if they don't grow a third crop, they are trapped. It is the lack of alternatives to low-value rice production that helps explain why the delta is home to the largest number of poor people in Vietnam.
In 2013, the government, with Dutch technical assistance, produced the Mekong Delta Plan (MDP), which outlined a development strategy based on investment in no-regrets projects that make economic sense and don't lock the delta into an unsustainable and unaffordable development trajectory.
The MDP was a milestone because, for the first time, it stated explicitly that decisions over land and water imply trade-offs between economic sectors, geographic regions, and social classes. The MDP's recommendations have influenced a World Bank climate change adaptation project that is currently being designed and will support changes in land and water use that are cost-effective and avoid the risks of mal-adaptation.
The MDP was modelled on similar experience in The Netherlands. In 2008, realizing that the country was not prepared for climate change, particularly in light of the 2005 Katrina disaster, the Dutch Delta Programme (http://www.government.nl/issues/delta-programme/introduction-to-the-delta-programme) was established based on the principle of adaptive management that embeds uncertainty into the decision making. This is done by ensuring that short-term decisions don't close off long-term options, prioritizing flexibility, taking advantage of the huge improvements in weather forecasting, and following development pathways rather than fixed end points. In the words of one participant: "when it comes to deltas, the traditional 5-year planning cycle is dead."
This approach has resulted in a shift away from structural to environmental measures that are often cheaper and provide additional economic and cultural benefits. These include beach nourishment using offshore sand, and opening up of two of the largest sea dikes to re-establish tidal flows to improve water quality and allow the recovery of the lucrative shell fish industry.
To ensure that expensive investment decisions are based on the best possible analysis, a Delta Law was passed in 2011 that established a Delta Programme, a special functionary called the Delta Commissioner, who reports to parliament and is independent of ministries, and a Delta Fund, which receives €1 billion/year. At the Mekong Delta Forum in HCMC in February, a senior Vietnamese government official suggested that the Mekong Delta could benefit from this model.
Vietnam has a great deal to learn from the Dutch experience, which combines political reforms, public engagement, new technology, and cost-benefit analysis. In Vietnam, the greatest challenge is how to get different provinces and ministries to cooperate for mutual benefit, in other words, how to implement planning at the scale of the delta that recognizes uncertainty, rewards innovation, and adapts to new information.