| Climate variation and change | Typhoon/severe tropical storms:
From 2005 – 2010, Da Nang has 8 storms that landed or directly impacted the city. The majority of these storms had recoded wind levels of 11, while before 1998, each year had an average of 1 storm that recorded a wind level over 11.
In the past years, the storms appeared early, unseasonably and more unusually, the frequency of storms has increased significantly. The riparian areas, coastal are frequently affected by storms.
Storm surges/flooding:
In Da Nang city, flooding usually occurs in rivers: Cu De, Tuy Loan, Han due to heavy rainfall, and concentrated, long rain spells. Due to the influence of rainfall changes, in the past 10 years, flooding occurred sooner, often appearing unexpectedly, unpredictably with predominant frequency and intensity. Before 1998, there were 10 years per one super flood. In the 10 year period from 1998 to 2009, there have been six particular super floods occurred in the years 1998, 1999, 2004, 2005, 2007 and 2009.
Sea level rise:
Currently, is no data on sea level rise in the city of Da Nang. However, according to the national target program on climate change adaptation of Ministry of Natural Resources and Environment, the annual average sea level rise is about 3mm in Vietnam during a 16 year period (1993 - 2008) and Da Nang sea level has risen approximately 1.3 mm (measured by satellite station in Son Tra)
Drought:
According to the Agricultural and Rural Development Sector, during 2005 - 2009, there were 2 droughts in 2006 and 2008. There was no damage to people and property, but the area affected by drought was relatively large. Under the impact of climate change, drought trends will intensify and will continue for the following years. |
| Other natural threats and hazards | Coastal erosion:
Effects of storms, especially the November 1999 floods, have caused 8 serious erosion points with a total length of 7.97 km, with an average width of erosion marks from 0.5 to 15m. Many riparian areas have severely eroded such as the Cu De, Tuy Loan, Vinh Dien River. The Cu De River has many sections that have eroded – up to 10m after each flood. In addition, Lien Chieu, Thanh Khe, Son Tra coastal district, Ngu Hanh Son, have areas that have eroded up to 50m.
Sedimentation:
• South Hai Van Pass area from of Mui Nhoi to Van Village, coral reefs died completely and platform reefs covered mainly by Sargassum (Sargassum) and (Rosenvingea), rong tai beo (Padina) and sediment.
• South of Son Tra peninsula area decrease 1.6 ha compared with the results of previous studies and Bai But in recent times, the reef area lost an estimated 5ha. The cause was determined to be affected by many factors, including the polders and sedimentation.
Landslides:
Areas affected by floods and landslides: Primarily includes 6 midland and mountainous communes that are located along Tuy Loan, Cu De river. Belonging to Hoa Vang district are Hoa Phu commune (9 villages), Hoa Nhon commune (6 villages), Hoa Khuong (2 villages), Hoa Lien (5 villages), Hoa Ninh (3 villages), Hoa Bac (6 villages) and some locations of Son Tra district (Suoi Da, Hoang Sa Street) and Lien Chieu (Suoi Luong).
Areas affected by river erosion: Include areas along Yen River, Cu De River, Tuy Loan River, Vinh Dien River with 8 communes with 410 households (2,322 persons) |
| Other climate/man-made hazards | |
| Man-made threats and hazards | Oil spills (from sea-based or land-based sources):
From 2007-2010, there were 8 oil spills occurring consecutively in the sea area of Da Nang. Without objective reasons, specifics cannot be determined due to the offshore oil drift on shore. The main cause of this are petroleum storage depots which are too old (H182 warehouse, K83 warehouse), and weather problems (Aviation fuel storage).
Domestic garbage/solid waste: 203.516 tons/day (2009)
Industrial and hazardous waste: 9996.54 tons/day (2009)
Overfishing/destructive fishing:
Using electricity, dynamite (5-7 units per year)
Over-exploitation/destructive use of habitats (mangroves; coral reefs; seagrass):
Overfishing and unsustainable exploitation:
The destructive use of resources such as electrical impulses, explosives, detonators in recent years has reduced but still occurs. Each year an average of 7-8 cases of using electrical impulses and/or explosive cases detected and disposed. Tourism development and infrastructure construction is also a cause for destructive use of habitats
Uncontrolled development of the coastline/conflicting uses:
The surface area of coastal areas shrunk to serve economic development, especially marine tourism development with restaurants, seaside hotels. This has an impact on coastal water quality, affecting aquatic ecosystems in the region (Bai But, Hon Sup, Bai Lo, Bai Nam and Bai Nom, where there are coral reefs and seagrass beds.) Expanding the infrastructure construction on areas with potential high biodiversity, sediment is generated during construction of coastal areas. Insufficient study has been made towards the environmental impact of the affected reef area. The discharge of waste products and exploitation of plastic bags, fishing nets and other equipment has a negative impact on ecosystems and resources in the area.
Land reclamation: Area of integrated urban golf field Da Phuoc project is 1,815.085 m2 (include polder area).
Polluted groundwater:
Domestic wastewater of households (septic tanks) is one of the causes of polluted shallow groundwater. Among households with septic tanks, only a small proportion of effluent treated by septic tank is connected to the urban drainage system, meaning waste water is most self-absorbed, not to mention the quality of the septic tank is poor, causing pollution of groundwater. The most common pollutants are organic compounds and microorganisms. Wastewater from service activities such as; hospital wastewater, resorts, luxury hotels in the city adds to this pollution. Industrial Wastewater and other sources of pollution, like the Khanh Son dumpsite, production, businesses and services all contribute. Agricultural development via cattle-breeding, poultry, use indiscriminately chemicals, plant protection products. Geological Drilling Activity is a factor, as a canal system has not been dredged.
Overuse/mismanagement of groundwater supplies:
The exploitation of excessive ground water causes salination, and the contamination of aquifers.
Salt water intrusion:
The main supplied water for the city is Cau Do river. Water is carried out at the place, which is 15km from the estuary. This area is often intruded by salt water in dry season, usually there is more than 1,000ml/year. In general, ground water quality of the city is relatively good.
Hypoxia/eutrophication of coastal waters:
The pollution of Phu Loc river is nutrient pollution. Nutrient pollution in the river of Phu Loc river in 5 years has no positive changes; NH4+ is higher than the allowed standard. In the last 5 years, the organic matter and nutrients in some locations on the river exceeded the standard, but not at a high level.
Invasive marine species:
Marine resource protection inspectors checked 19 ornamental fish business establishments, collaborated with the Forest Protection Department, Environmental Police mobilized people and institutions to destroy 32 red-eared turtles. |
