At the beginning of this century a national sea dike was constructed along the entire coastline of Vietnam minimize the incidence of storm surge and the intrusion of saline water into agricultural areas. Today there are 3000 km² of sea dikes and 5700 km² of river dikes in the country (Hoc, 2010). Historically, both the capital and technical capacity to construct and maintain dikes was provided by external sources. Within the last decade, both local labor and local tax revenues have been increasingly used to develop dikes. Historically, sea dike development has been focused on northern and central Vietnam which are the areas most exposed to typhoons. Projections of sea level rise and increases in storm intensity and frequency show that southern Vietnam is becoming more vulnerable to storm surge and saline intrusion. Motivated by these projections and Typhoon Linda in 2007, a new Dike Development program has begun to focus on the South. This program will restore and upgrade the 900 km sea dike system from Quang Ngai province to Kien Giang province (see Map 1), and was approved by the Vietnamese government on May 27, 2009 under Decision 667. Most of the VND 20 trillion budget that has been allocated to this program will be provided by the national government through a national target program that is discussed later in this chapter. Funding will also be sought from international donors, the private sector, local government and local households. The establishment of a “protective” mangrove forest situated between the sea dike and the coastline with a minimum width of 500 m is a mandatory condition written into this Decision (667).
Mangroves, a soft climate change adaptation measure: Vietnam has lost over 80% of its mangroves since the 1950s. Spraying of defoliating agents during the Vietnam War and the rapid expansion of the aquaculture industry during the early 1980s are considered as the two major causes for the decline. In response to this, mangrove restoration and rehabilitation has been ongoing since 1991, but the process of decline was only reversed in 2001, as indicated in Figure 1 below.