Ca Mau has 03 major water sources with strong relationships, strongly affecting the process of land use including rainwater, salt water, and groundwater.
During the harvesting season. Photo: Huynh Lam.
Rainwater: As a source of fresh water, rainwater is supplied annually from 6-10 billion m3 of water. Rainwater is stored in freshwater channels during the rainy season and forms freshwater areas in the area. Currently, this water source is mainly left in the U Minh Ha cajuput forest area, the agricultural production area in the north of Tran Van Thoi and Thoi Binh districts. This is the main source of water for agricultural production, animal husbandry, and partly for living so that some areas can produce rice, vegetables, and industrial plants. This area has been shrinking over the years.
Rainwater is mainly left in U Minh Ha cajuput forest.
Saltwater: This is the water that is introduced from the sea or mixed with rainwater. Saltwater is not suitable for freshwater young trees, on the contrary, salt water is a resource to develop aquaculture, salt making, and mangrove development, etc. In fact, the fisheries sector has been a key economic sector that has made great contributions to the socio-economic development of Ca Mau province in the past years.
Saltwater is suitable for aquaculture. In the photo: model oyster cage breeding on the river in Ngoc Hien district.
In the dry season, the salinity of river water and water in shrimp fields increases, often in estuaries with higher salinity, the deeper into the field, the fewer salinity decreases. In contrast, in the rainy season, salinity decreases rapidly (both in river water and in shrimp farms). Therefore, some areas with good salinity and sweetness conditions can produce a crop of rice on shrimp land during the rainy season.
Underground water mining in Ca Mau. Photo: Huynh Lam.
Groundwater: This is an important source of clean water for residential activities and agricultural processing. Without good management, exploitation, and protection, Ca Mau will lose this precious and important resource in the future.
According to the survey results of the Southern Geological Map Federation, groundwater in Ca Mau province has large reserves, quality assurance for living, and industrial production. There are 07 underground aquifers in the following order: All groundwater from layer II to layer VI is pressurized groundwater, and the additional supply domain is defined as from the Southeast area and Cambodia. Layer VII: Freshwater on this layer is newly encountered when drilling on Hon Khoai island, with a depth of 372 m to 413 m, this layer has no pressure.
Clean environment - developing shrimp farming. Photo: Huynh Kim Hai.
Total underground water exploitation potential reserves of Ca Mau province is about 6 million m3/day; of which, the first layer is 0.64 million m3/day, the second layer is 1.2 million m3, the third layer is 1.53 million m3, the fourth layer is 01 million m3, the fifth layer is 0.9 million m3, the sixth layer is 0.75 million m3. Currently, underground water in the province is mainly exploited in layers: II, III, and IV (individual wells of households are mainly exploited in layers II and III). However, currently, the water source on the second layer in many areas of the province has been polluted, so the water source used is mainly exploited in the third and fourth layers, with an average depth of 180 - 200m, which is an underground water source with high pressure, abundant reserves and good quality. This is an important source of clean water for residential activities and agricultural processing. Without good exploitation and protection management, Ca Mau will lose this valuable and important resource in the future.
Combined rice - shrimp production model. Photo: Huynh Lam.
In addition, the survey results show that Ca Mau province has three sources of mineral water. Including:
- Mineral water source in Thoi Binh town, Thoi Binh district: Belonging to the borehole S147, located near to river junction, constructed by Association 804 in 1996. The mineral water source was discovered in a borehole 258m deep, with a flow of 23 liters/second. The analysis results show that Thoi Binh mineral water has the chemical composition of bicarbonate natrium, low mineralization, classified silica, warm mineral water. Currently, this mineral water resource is exploited, supplied for domestic use.
People harvest water chives belonging to the group of aquatic living trees, grow in regularly flooded areas, and adapt to low-lying land. Photo: Huynh Lam.
- Ca Mau mineral water source: Belong to borehole 215, constructed by Association 802, of the Geological and Hydrological Federation in 1996, located in the former headquarters of the Ca Mau Police Department of Fire Prevention and Fighting (ward 2, Ca Mau city). Water appears in the borehole 328m deep. The results of the analysis show that this is a sodium bicarbonate mineral water, low mineralized above and lower segments, classified as warm water above and warm mineralized water below.
- Nam Can mineral water source: Belong to borehole S141, near the headquarters of Nam Can district People’s Committee (in Nam Can town). The water source was discovered at the depth of 257m, the flow is 11 liters/sec, the lower water level is 21,89m. The analytical results show that this is bicarbonate mineral water -chloride - sodium sulfate, medium mineralized, classified as warm mineralized water. Currently, this source of mineral water is exploited and supplied for domestic use.