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Hydrology

10:54 07/02/2018

Thai Binh province is located in the monsoon tropical area, it receives an great annual rainfall (1,700 – 2,200 mm). In addition, the area is separated by large rivers, which are tributaries of the Red River, before running into the sea

Rivers

Thai Binh province is located in the monsoon tropical area; it receives a great annual rainfall (1,700 – 2,200 mm). In addition, the area is separated by large rivers, which are tributaries of the Red River, before running into the sea. On the other hand, due to the process of agricultural production, through many generations, people have created a dense river system. The total length of the rivers of Thai Binh is up to 8492 km, the average density is from 5 to 6 km/km2. The flowing direction of the rivers is mostly northwest - southeast. The north and northeast of Thai Binh are influenced by Thai Binh River.

River system outside the dike:

Thai Binh is surrounded and bisected by the following major rivers:

To the west, southwest and south (the confluence of Luoc river to Ba Lat estuary), the meandering Red River is the major water supply and silt source for Thai Binh.

To the northwest, there is Luoc River (a tributary of the Red River), the river supplies water for Quynh Phu district and Hung Ha district.

To the northeast, there is Hoa River flowing into Thai Binh estuary

Tra Ly River (a tributary of the Red River) comes from the Red River to the sea, dividing Thai Binh into two zones: the northern zone and the southern zone

Diem Ho River flows through a part of Dong Hung district and divided Thai Thuy District into two parts (the former parts of Thuy Anh and Thai Ninh) and flows into the sea via Tra Linh drains.

Thai Binh can be said as a “isle" with three river sides and one sea side.

River system inside the dike:

In addition to the river system outside the dyke, Thai Binh also has a dense system of rivers inside the dyke which is mainly for irrigating fields and living activities of the people. Below are some local rivers of the province:

Northern Thai Binh region:

Tien Hung River: was previously a natural river running around Dong Hung and Hung Ha districts. The river is 51 km long and 50 – 100 m wide, irrigating lands along rivers and serving as important waterways of this region.

Sa Lung River: a canal was built from 1896 to 1900 with the length of approximate 40 km, flows through the districts Hung Nhan, Duyen Ha (now being Hung Ha) Tien Hung, Dong Quan (now bieing Dong Hung district), Thai Ninh (now being Thai Thuy district).

Quynh Coi River: Also known as Yen Long River or Ben Hiep River. This is the canal through a portion of Quynh Phu district, downwards Dong Hung, with a length of about 15 km, starting from Ben Hiep drain, connected to Tien Hung River in Lien Giang Commune.

Dai Nam River: It is also a river that runs through Quynh Phu district with the length of 16 km, starting from Dai Nam sewer connected with Diem Ho .

Diem Ho River: It is the most important water drainage river in the irrigation system in the north of Thai Binh. Most of the inland rivers in the area flow into Diem Ho River. When Tra Linh drawer was not available, Diem Ho River became the river inside the dyke the main function of which is to drain water for the northern districts of Thai Binh.

 Thuyen Quan river: It is a 9km long canal, linking with Tien Hung River in the boundary of Dong Giang commune – Dong Kinh commune with Sa Lung River in Vinh Dong commune, and Tra Ly River in the boundary of Dong Linh commune (Dong Hung) - Thai Ha commune (Thai Thuy).

He River: It connects Hoa River with Diem Ho River, is 12km in length, and runs through some communes of Quynh Phu district, Thai Binh.

* Thai Binh Southern Region

Cu Lam River: It flows from Tra Ly river in Xuan Hoa commune through Hiep Hoa, Song Lang, Minh Lang, Minh Quang communes, connects with Vinh Tra River in Vu Thu Town, Vu Thu district . This stretch of the river is 14 km long.

Bung River: It flows through Hiep Hoa , Viet Hung , Dung Nghia, Tan Lap commune, connects Tra Ly river with the Red River, with the length of approximate 13 km.

White River: It flows from Nang culvert (Tra Ly River) at the boundary of Tan Hoa and Phuc Thanh communes winding through Phong Tan, Tan Binh (Vu Thu), Tien Phong Ward, Phu Xuan commune, connects with Tra Vinh River in Phu Thanh, Thai Binh City.

Kien Giang River: It is a canal with several different reaches. The main flow is from Tra Vinh River in Thai Binh City, through some communes of Vu Thu district and then through Kien Xuong District, Tien Hai, then into Lan River with the length of 30 km. This river is important for irrigating fields in the south of Thai Binh and serves as an important water transport in the region. It can be said that it is the backbone of the irrigation system in the south of Thai Binh. Thai Binh has a system of rivers and canals connected to the Red River and Tra Ly River through sewers. Most of the other rivers in the region are linked to Kien Giang River, for example, Nguyet Lam River, Duc Duong River... . Kien Giang River is a quite beautiful river, the banks of which are places for dense population, fertile and verdant villages.

Nguyet Lam River: It is a canal from Nguyet Lam culvert, fetching water from the Red River (Vu Binh commune, Vu Thu district), in connection with Kien Giang River in Hoa Binh commune, Kien Xuong district with the length of 13 km.

Duc Duong River: It is also a canal from Duc Duong culvert, fetching water from Tra Ly River in Tra Giang commune, connecting to Kien Giang River in Binh Minh commune, Kien Xuong district with the length of 13 km.

Huong River: Connecting Red River to Kien Giang River, from Binh Thanh Commune of Kien Xuong district to Phuong Cong commune of Tien Hai district .

Lan River: It is formerly a branch of Red River, flowing into the sea. It now becomes the river inside the dike, running from the boundary of Hong Tien commune (Kien Xuong District) – Nam Hai (Tien Hai) to flow into the sea. Since the dyke was filled and Lan culvert was constructed, it became an inland river. The river irrigates for Kien Xuong district and Tien Hai district. Lan culvert is in charge of preventing salt water and draining water in case of infield flood, as well as regulating irrigation for the south Thai Binh region.

Long Hau River: Connecting Tra Ly River with Kien Giang River from Dong Quy commune to Dong Lan commune (Tien Hai).

The process of formation of large and small rivers of Thai Binh is a combination of natural development and demand for productive and human activities. The river is formed by the natural movement of the flows, starting from the upper basin towards the lower basin, the flow direction always changes because of many meandering rivers. In the past, Red River flow changed frequently. Since the dyke system was formed, the flow of Red River has been almost stable to have today’s appearance. The River system inside the dike is the result of human conquest to limit the effects of natural disasters, take advantage of natural conditions for agricultural irrigation. Over many decades, Thai Binh farmers has continuously improved, dug deeply, diverted inland rivers for irrigation and partly serving the waterway transport.

 Ponds and lakes

In Thai Binh, there is no large lake or pond but mainly small ponds, which are interspersed with villages or adjacent to dikes, coastal due to taking land for embankment or dike break to form the hollow position of water. These small lakes are scattered, interspersed with residential areas as a result of the process of residential land creation. In the past, the soil was not flat, somewhere low and somewhere high, people dug ponds to take soil to fill house floors, create gardens, and took advantage of water source from ponds around houses to get fresh water. Therefore, most of the villages and residents of Thai Binh (houses, fields and gardens) are close to ponds. Total area of ​​lakes is nearly 6,575 ha, accounting for 4.25 % of the provincial land. The lakes of Thai Binh usually do not have large area (approximately 200 – 300 m2). In recent years, the area of several lakes has been renovated, tended to focus on the farms for shrimp and fish farming by semi-industrial processes. Initially, some fish and shrimp farming ponds have brought high economic efficiency, especially shrimp farms in the coastal ponds (giant tiger prawn, greasybock shrimp... )

Sea

Thai Binh sea is located in the sea of the Gulf of Tonkin, part of the East Vietnam Sea. East Vietnam Sea is a large sea connecting with Pacific Ocean through the wide straits.

The Gulf of Tonkin lies in northwest of East Vietnam Sea, is actually part of the submerged continent in sea water so that the sea is shallow, the deepest position is not more than 200 m.

Underground water

Thai Binh is part of the Red River delta triangle, of the sediments of the Quaternary separate bank with river - sea mixed origin. In general, this sediment is capable of reserve great water, the underground water level is shallow and easy to exploit.

According to the study of geology and hydrology, the area has the geochemical hydration zonation horizontally and vertically as follows:

 Horizontal hydration zonation:

Horizontal hydration zonation, taking Tra Ly River flowing in the middle of the province as the boundary: The north of Tra Ly River consists of Hung Ha district, Dong Hung district, Quynh Phu district and some communes of Thai Thuy district next to Hoa River area. It locates in the freshwater zone with a total mineralization of from 300–500mg/l. The fresh water aquifers are very good. The south of Tra Ly River includes Vu Thu District, Kien Xuong District, Tien Hai District, most of Thai Thuy district and Thai Binh City. It locates in the saltwater area. The drill holes show that drilled water has a total mineralization of 600–2,500mg/l, the water is of sodium chloride category. Because the water is salinity, it does not meet the standard for drinking water .

- Vertical hydration zonation

Vertical hydration zonation from the ground to a depth of 140m includes the following layers of water separation and water containing:

+ Poor water containing layer in Thai Binh formation

+ Water separation layer from Hai Hung II formation

+ Little water containing layer at Hai Hung II Formation

+ Water separation layer from Vinh Phuc I formation

+ Pore water containing layer from Vinh Phuc II Formation

+ Water containing layer in the sand - pebble - gravel sedimentary of Hanoi Formation

Water resources, exploitability and current use

Surface water resources

Water is a really precious resource. It participates in the living activities of animals, plants and humans, deciding the public health and crop yields. In industry, water is indispensable in the chemical production, agricultural processing, pharmaceutical processing ...

Water plays a very important role in our life, so we need to exploit and use water in a scientific way to serve the community life. The exploitation and use of water resource is based on the spatial distribution characteristics and of hydrodynamic characteristics.

The water resource in Thai Binh surface flow is very rich. The dense system of rivers contains and circulates a huge amount of surface water. It is a giant supply source of billions of cubic meter of water from the major rivers such as the Red River, Tra Ly River, Thai Binh river plus the very large amount of annual rainfall(billions of tons). These are favorable conditions for residents to use water resources to serve their living and production everywhere in the province. The surface flows were used to irrigate the fields through irrigation systems: ditches, watering canals, gravity sewer system...

On the big river dyke system, there are many culverts taking water from the river to irrigate fields, the water from Red River, Tra Ly River, Thai Binh river ... is used to irrigate the fields, accordingly provides a considerable amount of sediment, making the field of Thai Binh increasingly fertile.

The surface flow of the inland rivers, besides irrigation for the fields and the life of residents, brings the liquid waste to flow into the East Sea (domestic waste water, deacidification water, salt field washing).

The surface flow system, especially the winding inland river system, horizontally and vertically in Thai Binh, creates landscape and a harmonious, tranquil and dreaming setting of river, fields and orchards .

However, in recent years, because of the unreasonable and unscientific use of surface water resources in some places and and the unaware use of surface water of the part of the population, surface water has become polluted in some places, resulting in poor quality water that , fails to meet standards for drinking water. Therefore, the community needs to be educated the awareness of protecting water sources, water resources which the nature presents to humans.

To better protect the surface water resources, in addition to educating the community of the awareness of water resource protection, it is necessary to take synchronized measures:

- Strict management of industrial waste water sources, domestic water (Treatment of harmful substances before pouring into the river system is necessary).

- The flows need to be dredged by regularly dredging the infield rivers. Restrict the encroachment of river systems, which impede the flow.

- Coordinate the regulation of flows through the irrigation system smoothly and scientifically.

- Industrial waste, domestic waste in densely populated areas should be collected for treatment, not littered down into the river, causing pollution and clogging the flow.

- In agriculture, the use of pesticides must comply with the direction of the professional bodies and be examined closely, pesticides should not contaminate the surface water.

- The water used in the activities of the community should be treated, ensuring clean water for life .

Underground water resource

As mentioned above, the underground water resource of the surface layer and deep level of Thai Binh are relatively abundant, but most of them can not even be used for living activities.

The shallow containing layers have high iron content, which exceeds the permitted standard. To be used, it must be treated to reduce iron content, guaranteeing the specified standards. It is shown in most of the wells pollution of organic matters due to remnants of plants, with toxic ions such as NH4, NO2, P04, S. ..

The pore water containing layer in the sediments of sand - pebble - gravel of Hanoi formation which has a depth of 80–140m has large water storage capabilities, is valuable in both quantity and quality for the medium and small water treatment and supply stations. Because the water containing layer lies deeply, the potential to cause water pollution in this layer does not exist because of being protected by the upper water containing layers. However, to ensure safe exploitation and use, measures of protection and reasonable exploitation should be noted.

The surface underground water of Thai Binh can be taken by digging down 1-1.5m into the ground in dry season and less than 1m in rainy one. However, it is only surface underground water, if deeply digging, salt and sour water will be seen, the transparence level is of uncertainty. As a result, water can not even be used in daily life and needs to be treated. The deeper it is inland (Quynh Phu, Hung Ha), the less the salinity and acidity is.