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1. Geographical location: Dong Hoa town is located in the South Central coastal region, with both plains, hills and mountains, and the sea in Phu Yen province, with geographical coordinates from 12045'59" to 130 03' 10 north latitude, from 1090 16' 15" to 1090 28' 05" east longitude, with a total natural area of 26,828.46 hectares.
The boundary of Dong Hoa town is adjacent to the following localities:
+ The North borders Tuy Hoa city and Phu Hoa district.
+ The South borders Van Ninh district - Khanh Hoa province.
+ The East borders the East Sea.
+ The West borders Tay Hoa district.
Dong Hoa town has National Highway 1A which is a cross-Vietnam route, National Highway 29 from Vung Ro port to the Central Highlands, the North-South railway and Vung Ro port to the East Sea, especially the East bordering the East Sea, which has created a unique advantage for the town. The commune has a favorable position in socio-economic development exchanges with neighboring provinces and marine economic development.
2. Terrain and geomorphology: Dong Hoa town has the characteristics of the South Central coastal plain, gradually sloping and lowering from West to East, with the following 2 basic terrain types:
* Plain area: Flat terrain is located in the North of the town, in the form of riverine plain terrain, extending from West to East, with high elevation. small. The East is the coastal sandy land, the Northwest is the alluvial land deposited by the Da Rang and Ban Thach rivers. Ban Thach River flows from West to East through the town.
The main slope direction is from West to East and gradually slopes towards Ban Thach river. The average slope is 0.05%.
+ Average natural ground elevation +2.5 m to +3 m.
+ The highest area along National Highway 1A, with elevation +5.5 m to +5.7 m.
+ The lowest area along both sides of Ban Thach River, base elevation from +0.5 m to +1.5 m.
* Hilly area: located in the south of the town, stretching from West to East, accounting for a large amount of the town's natural area. The divided terrain is quite complicated. The average altitude is 400 m to 500 m, the mountain slope fluctuates greatly.
3. Climate characteristics: Dong Hoa town is located in the Central Coastal climate zone, the climate is divided into 2 distinct seasons, the dry season and the rainy season;
+ The rainy season is from September to December. Although the rainfall is large, it is unevenly distributed throughout the months of the year. Heavy rain is concentrated in October and November. This season's rainfall accounts for 70 - 80% of the yearly rainfall. The number of rainy days accounts for 30%.
+ The dry season is from January to August, the rainfall in the dry season months accounts for 20 - 30% of the total yearly rainfall, the number of rainy days accounts for 50% but the rainfall intensity is small, usually from 1 - 10 mm.
* Rain:
- Average annual rainfall: 1800 - 2000mm.
- Highest rainfall: 2341mm.
- Lowest rainfall 856mm.
* Humidity:
- Average annual humidity: 80 - 90%
- The month with the highest humidity is October or November: 90%
- The month with the lowest humidity is April or May: 35%.
* Temperature
- Average annual temperature: 26.50C
- Average annual highest temperature: 29.30C
- Average annual lowest temperature is 23.20C.
The annual average temperature does not change much, fluctuating from 4 - 60C.
* Main wind directions of the year: every year there are two main wind directions, the Northeast monsoon in the rainy season and the hot, dry Southwest wind (Lao wind) in the winter. dry season. The annual average wind speed fluctuates between 2 - 2.5m/s, the strongest wind speed is in May to June: 25m/s; Minimum wind speed in December to January: 10m/s.
* Steam mode:
- Average annual evaporation is: 650 mm.
- Month with the highest evaporation: 90.5 mm (June and July).
- Month with the lowest evaporation: 24.5 mm (October). The rainy season months have evaporation lower than the amount of rainwater, whereas in the dry season months the evaporation is 3.6 times higher than the amount of rainwater.
In general, the hot and warm weather is quite stable, usually lasting 9 months of the year, from March to November. It is clear that the heat regime in Dong Hoa town shows a short, not cold winter and a long summer. Hot weather is quite favorable for agricultural production.
4. Hydrology: Dong Hoa town has two large rivers flowing through it, Da Rang river and Ban Thach river. Ban Thach river is one of the 3 largest rivers in Phu Yen province. Ban Thach River originates from high mountains in the south and southwest of Tay Hoa district at an altitude of 1000 - 1500m. Ban Thach River has a total length of 58km, basin area of 600 km2, flows in the West-East direction, average flow of 12 - 15m3/s, upstream has a slope of 7.5%, flows through an area with high altitude. slope 0.2%. Da Rang River is the longest river in the Central Coast region, originating from Kon Tum province at an altitude of 2000 m, flowing through the town in the West-East direction, with a basin located in the area with the highest rainfall in the province. The average water volume is 280 m3/s, so it often causes floods in the southern region of Dong Hoa town. In addition, there are Dong Khon lake, Hon Dinh lake, Tan Giang dam, Dong Lau dam, Bien Ho, three stream dams and irrigation water systems of Dong Cam and Bien Ho irrigation systems, convenient for agricultural production and aquaculture.
5. Resources
5.1. Land resources
According to the results of agrochemical soil investigation, the land of Dong Hoa town includes the following main soil types: alluvial soil, gray soil, Feralit soil developed on granite sandstone, saline soil, sandy soil. .
5.1.1. Alluvial soil group (P)
The town's alluvial soil is concentratedly distributed in the Northwest, deposited by the two rivers Ban Thach and Da Rang. This soil group has two types: alluvial soil that is deposited annually and alluvial soil that is not deposited annually. The soil has quite high nutritional content and is suitable for many types of crops. Suitable crops are food crops, flower crops, fruit trees,...
- Alluvial soil is deposited annually: distributed along riverbanks, concentrated in high terrain areas, light mechanical composition, less acidic or neutral, nutritional content from fair to rich, suitable for grow short-term industrial crops and vegetables.
- Alluvial soil that is not deposited annually: usually concentrated far from the river, where the terrain is high, the mechanical composition is light, less acidic, poor in phosphorus and potassium, suitable for growing short-term industrial crops, rice and trees. vegetable.
5.1.2. Gray soil group (X)
Gray soil is formed on ancient alluvium and sandstone, mainly distributed in Hoa Xuan Dong, Hoa Xuan Tay, Hoa Tan Dong... The soil is characterized by light to medium mechanical composition, acidic soil reaction, Low basic saturation, poor humus, poor total and digestible nutrients. The land is suitable for upland crops, industrial crops, rice and fruit trees. If you can proactively irrigate, fertilize and reduce acidity, you will improve land use efficiency.
5.1.3. Feralit soil group develops on granite sandstone slabs (F). Feralit soil developed on sandstone granite is distributed in Hoa Tam, Hoa Xuan Tay, Hoa Xuan Nam. Soils often have an acidic reaction, low basic saturation, average nutrient absorption ability, have relative and absolute accumulation of iron and aluminum, and are easily eroded and washed away due to being located in high, steep terrain. numerous and strongly fragmented, if not used properly, it can easily lead to land degradation. The appropriate development direction is afforestation.
5.1.4. Saline soil group (M)
The saline soil of Dong Hoa town is distributed along the coast and estuaries, including 2 groups: highly saline soil, medium and low saline soil. The main characteristics of saline soils are that they contain a high amount of salt, average to good nutrient content, average mechanical composition, and the soil has a neutral reaction, slightly acidic to slightly alkaline.
- Highly saline soil: formed in low terrain, coastal areas, estuaries, often strongly influenced by tides and in some places due to saline water containing NaCl salt in sea water, soil with medium mechanical composition. average, the closer it is to the river mouth, the worse it is and the salinity changes with the seasons: in the dry season, the water dries up, so the salt concentration in the soil is high, making the soil more salty in the rainy season. The direction of using saline land is mainly for aquaculture. If it is improved and salinized, rice can be grown.
- Medium and low salinity soil: formed in high terrain from the products of river and sea alluvium, often adjacent to alluvial soil, soil with neutral reaction, less acidic, with loam texture. medium to heavy flesh, brown, dark gray, purple brown, medium protein, poor to medium phosphorus. Directions for use are rice growing, crops and aquaculture.
5.1.5. Coastal sandy soil group (C)
The coastal sandy soil group is distributed in all communes with boundaries with the sea such as: Hoa Hiep Bac, Hoa Hiep Trung, Hoa Hiep Nam, Hoa Tam, Hoa Xuan Nam... The soil is characterized by light mechanical composition, Well drained, poor in nutrients, strong level of organic decomposition, low basic saturation, soil reaction is mildly acidic to weakly alkaline. Suitable crops are protection forests (sand protection), vegetables, crops, and short-term industrial crops.
5.2. Water Resources
a) Surface water source: Dong Hoa town has a main surface water source system from two rivers: Ban Thach and Da Rang, with relatively abundant water;
+ Ban Thach River: A river with a fairly large basin area of 600 km2, 58 km long, average flow of 12 - 15 m3/s, upstream with a slope of 7.5%, flowing through a sloping area. 0.2%.
+ Da Rang River: Is the longest river on the Central Coast, originating from Kon Tum province at an altitude of 2000 m, flowing through the town in the West-East direction, with an average flow of 280 m3/s. Dry season flow is 30 - 40 m3/s.
There are also Dong Khon lake, Hon Dinh lake, Bien Ho, Tan Giang dam, Dong Lau dam and irrigation water system of Dong Cam irrigation system, Nam Binh pumping station.
b) Groundwater source: Groundwater source is easy to exploit, but there are some areas that are contaminated with alum, oil, hard water, and iron content exceeding the allowable level. Groundwater depth ranges from -3.2 m to -0.8 m.
5.3. Forest resources
Dong Hoa town has a total forestry land area of 12,202.41 hectares, of which production forest land is 2,738.89 hectares; protective forest land 1698.67ha; 2,102.20 hectares of special-use forest land in Deo Ca area.
Flora: natural forests are mainly closed broad-leaved forests, rich in species structure, diverse in tree types, and have high protection ability. The forest is mainly planted with trees such as Eucalyptus, Acacia Melaleuca, Acacia mangium, Casuarina and some other species.
Forest animals: According to incomplete statistical data of the projects, the forest fauna of Dong Hoa town is quite rich with a full range of animals living together. Up to now, forest animal resources have decreased significantly in both quantity and quality, mainly due to extensive deforestation. Natural reserves such as Deo Ca forest are places that have both scientific value in biodiversity conservation and great significance for tourism and protection.
In addition to its significance in preserving biodiversity, the town's forests also actively contribute to climate regulation, water conservation, erosion prevention and creating tourist landscapes.
5.4. Natural resources
The biggest potential of Dong Hoa town is Granite and sand for construction. There are also peat mines in Hao Son and some other minerals.
5.5. Marine resources
With a location close to the East Sea, with a coastline of 48 km, this is an extremely valuable resource, creating strengths in the economic development of the town, with marine resources (especially aquatic products). ) is rich, it is necessary to take full advantage and exploit the strengths of the sea./.
