BARISHAL, Mar 9: Navigability crisis, salinity and erosion are affecting agriculture activities, posing a threat to local civilisation in southern (S) region.
According to field sources, agriculture activities and life are already in jeopardy.
Due to upstream river flow control, the water communication got disrupted; seatide makes gradual approaching towards upstream due to lack of adequate rainfall amid climate change, raising the salinity level.
In all 132 small and big rivers in the region, salinity level is continuing to increase. Due to navigability crisis, the boat communication is halted. The fisheries resources are under threat, according to sources at Water Development Board (WDB) and Soil Resources Institute.
The continuous control of the river flow in the upstream of border is increasing sediment on riverbeds; rivers are losing their water-holding capacities; that is why, in the rainy season, erosion by these rivers turns severe; due to lack of sound flow of the sea, Hilsha habitats are being changed. That is why Hilsas are gradually going to the deep sea. According to available estimates of river research institutes, 78 per cent of the water that the sea receives from the countrys rivers is carried and driven by sounthern regions 132 rivers including Meghna, Tentulia and Baleshwar.
In the last several years, 15 river administration projects were taken at more than Tk 5,000 crore. Most of these projects are under implementation. WDB sources said, already several erosion prevention projects have been completed.
Despite that WDB needs about Tk 10,000 crore to prevent erosion in some very important localities.
Due to lack of dredging and timely steps for erosion prevention, the 132 rivers are drying.
The navigability crisis has been continuing across about 500 kilometre (km) stretches of the total about 1,500 km river routes for the last several years.
Because of the same reason, fisheries resources of southern region having a surplus of about three lakh tonnes are under threat. Countrys about 70 per cent Hilsas are collected in the region.
In the last several years, salty water reached 100 km upstream, spreading across Barishal to reach Hizla Point of Meghna in the downstream of Chandpur by 50 more kilometre away.
Entire countrys water communicstions including three river ports are depedendent on rivers of the southern region. Payra Port is completely dependent on these rivers.
As there are navigability problems in Meghna and some other big rivers, there are risks in communicating with Dhaka, Chattogram, North Bengal via Chandpur and southern region including Payra and Mongla ports.
All types of boats including ferry are halted due to navigability crisis across 28km from Bhola Hilsha Ghat to Laxmipur Mozochowdhurirhat.
According to WDB sources, in January, the salinity was 610-630 ppm in the Khirtonkhola River in Barishal in 2006, and 910 ppm (January) in 2017. In 2018 the salinity decreased a little, but it increased to 900 ppm again in 2019. It was about 900 ppm in January in 2020.
The intolerable salinity is still below danger limit.
Even since April, 2021 the salinity has been continuing at 1,000 ppm in the river.
There was short rainfal in 2021. In dry season, the salty water entered the Madhumati River, and it was estimated at 2,100 ppm, the highest of all time against 1,200 ppm in 2016.
The salinity tolerance limit for agriculture, fisheries and human is 600 ppm.
Because of one-way water control in the upstream and climate change impact, lack of usual rainfall in 2021 and 2022 rivers of southern regions changed their characters gradually.
There was not adequate rainfall in the last rainy season. After autumn, heavy rain in the dry season damaged standing Aman and advance Rabi crops. Erosions turned severe. Both agriculture and fisheries were damaged, pushing up the local life towards jeopardy.
