Modelo de susceptibilidad aplicando el método de la relación de

Protection of sand dunes and mangroves in coastal zones of Vietnam

context: reduce the risk of coastal hazards and adapt to climate change problem: destruction of protective natural coastal zones (sand dunes and mangroves) through land use change

solution: awareness-raising and enforced coastal protection (mix of measures)

message: coastal ecosystems are coming under threat throughout the tropics and elsewhere, and action is necessary – for example to re-estab-lish mangrove forests – but alongside this there is an urgent need for awareness-raising

Along the coast in Vietnam, ecosystem-based disaster risk reduc-tion (Eco-DRR) and adaptareduc-tion (EbA) are considered suitable strat-egies to reduce the risk of coastal hazards and adapt to climate change. The potential of dune systems (Figure 2.42) and small mangrove remnants (Figure 2.43) for coastal protection in Quang Nam province (project research area) is summarized in Table 2.4.

Ecosystem Ecological Status Recommended Eco-DRR/EbA measures

Coastal dunes Medium to high degradation due to:

(a) replacement of native vegetation by non-endemic monocultures such as casuarina and acacia species

(b) agriculture and aquaculture activities;

(c) infrastructure development;

(d) sand extraction;

(e) waste disposal

(a) Establishment of awareness-raising and environmental education for coastal population on the multiple ecosystem services coastal dune

systems provide;

(b) Enhanced implementation of environmental legislation so that coastal forests on sandy shores are designated as ‘Protection Forest’

(c) Monitoring of land use changes in the coastal zone, as large stretches of coastal dunes are still being converted into agricultural land or shrimp ponds, and sand extracted for construc-tion purposes;

(d) Development of community-based restoration and conservation programmes including affor-esting measures with native trees and shrubs;

(e) Provision of financial incentives for coastal communities to actively support coastal dune con-servation

Mangroves Very high degradation status; most mangroves have been lost and the few remaining rem-nants are small and highly degraded due to wood extraction and waste deposition

Large-scale restoration of mangroves is difficult, due to land use pressure (infrastructural devel-opment, intensive land use). Suggestion: Improvement of ecological status and connection of remaining remnants. Community-based restoration programs of native species should be devel-oped and supported by government and development/ aid projects. To achieve good protection against typhoons, a mangrove belt of at least 200 m width is recommended.

Table 2.4: Ecological status and recommended Eco-DDR/EbA measures for coastal dune systems and man-grove remnants in the coastal zone in Quang Nam province, Central Vietnam

Conclusions

Overall challenges and opportunities

The growing demand for more land and water for agricultural, industrial and urban use and further societal claims are leading to changes in land use and management alongside challenges to find appropriate SLM practices that deliver services for people. These include changes:

• Within the main land use systems – often non-sustainable inten-sification.

• Conversion of natural and semi-natural land into agriculture and the conversion of agricultural and natural land into settlements, infrastructure and urbanization.

• Upstream land use and management affecting or conflicting with downstream uses.

What is required includes the following:

• Acknowledging the multiple demands on land and its resources while attempting to reconcile the various claims.

• Recognising both synergies and trade-offs between local and regional or landscape interests and potentials: interactions and interdependencies must be acknowledged and accommodated in planning and management.

• Limiting expansion or reducing the area where a particular land use is causing problems and has negative impacts.

• Taking into account water availability and quality – which con-sistently affects land use and management (and vice-versa).

• Using opportunities and rewards for carbon mitigation and bio-diversity protection.

• Reducing disaster risks through landscape management that recognises climate change impacts while assigning space for dif-ferent purposes and services provided.

• Using scenario building and modeling impacts as a knowledge-based tool that can deal with complex interactions and processes related to land management and its impacts. Results provide the basis for negotiation and informed decision-making.

• Utilising research – not just for analysing problems and develop-ing model based recommendations – but as neutral arbitrators within this stakeholder landscape.

• Above all is the need for better cross-sector cooperation and coordination through integrated landscape management. This is a core part of sustainable development: while not new, it needs to be repeated – and put into action.

River Basin management

Within river basins, watershed or catchments the dependency between upstream and downstream resource users is very high.

The key connecting agent between upland and lowland systems is water: its various facets remain a key area for research. Manage-ment is very complex as it must connect various scales, stakehold-ers and interests with numerous interactions and dependencies. A main concern is that upstream land use can cause either too much water flow in the lowlands or too little:

• Too much caused by inappropriate land management upstream resulting in high runoff, erosion and floods and sedimentation downstream.

• Too little when upstream overuse of river water for growing demands for irrigation or hydropower causes water shortage downstream (or diminishes the water quality).

• In addition, climate change is leading to changes in rainfall and temperature: increasing rainfall or decreasing rainfall or pro-longed dry and hot spells, droughts which causes new/addi-tional challenges. For all further research projects, the key challenge will be to project and explore options for the future as both climate and land and water management are changing.

The opportunities that have been identified are as follows:

• Development of an overall management plan involving all water users, and uses, to plan and regulate water distribution and land use. Adapt the plan continuously.

• Improved governance of hydropower and irrigation water man-agement.

• Improved land management to cope with extreme rainfall events and store the water in the soil or excess water in reser-voirs in upstream areas.

• Developing water storage systems and managing them effec-tively (including reservoirs and barrages/ weirs).

• Use of water efficiently during dry periods in both rainfed (e.g.

conservation agriculture no-till, minimum tillage, agroforestry, intercropping etc.) and irrigated land (e.g. re-using return water).

• Choice of land use according to available water (e.g. no high water demanding crop production in areas with water scarcity to reduce water demand for irrigation).

Riparian forest and water quality

Water quality is decreasing in several of the regions from within agriculture (agro-chemicals) as well as from the outside (salt water intrusion, eutrophication). These problems often increase with water scarcity. Indirect water pollution, coming from inappropriate land use needs to be identified and quantified in order to develop appropriate countermeasures. Pollutants mainly come from (i) soil erosion and agro-chemicals – including fertilizers which lead to eutrophication of rivers, reservoirs and groundwater, and (ii) irri-gation drainage or return water polluting water bodies leading to eutrophication or chemical pollution.

The opportunities identified can be summarised as:

• Erosion reduction through better local land management.

• Adapted irrigation management preventing salinization of soils.

• Protection of riparian forests and vegetation, as well as water protection zones.

• Protection and rehabilitation of coastal ecosystems, including mangrove forests.

Chapter 2     Landscape management - adapting to climate change 75

Coastal zones

Major changes in water use and management within river basins due to hydropower and over-abstraction as well as major changes of land use may lead to lower flow to the coastal regions during the dry seasons and higher peak floods during the rainy seasons.

Climate change leads to rising sea levels, and changes in seasonal rainfall patterns, and climate extremes and/or land management cause:

• Increased flooding due increased rainfall and extreme events.

• Salt water intrusion due to reduced river flow in the dry seasons due to over-abstraction of the river water for irrigation.

• Salt water intrusion in rivers or lowlands and in the groundwater due to increased sea level (in combination with above).

• Opportunities identified and principles for improvements:

• Regulations and agreements between upstream and down-stream users guaranteeing a minimum dry season flow.

• Creating flood retention areas to temporarily store freshwater and release it during dry seasons and low flows, simultaneously preventing rise of saline groundwater.

• Hindering salt water intrusion by blocking sea water flow into rivers during low flows, reducing ground water use and abstrac-tions from the rivers.

• Ecosystem-based disaster risk reduction (Eco-DRR) to protect the coastal zone from erosion, salt water intrusion and to adapt to CC.

To achieve significant impact, it is clearly evident that research must be implementation-oriented. However, research often lacks resources as well as cooperation from various stakeholders and sectors involved in river basin management – having different, and partly hidden, interests. Furthermore, even implementation-oriented research is a half-way stage in the overall process of trans-formational development. But it is a step in the right direction.