Kandawgyi Lake Flood Risk Control - Interview with Geologist, U Aye Ko (NEPS)
26 June 18 - Flooding is an obvious problem in Myanmar, mostly in downtown of Yangon and rural regions during monsoon season. Although we desired to live near water, nobody wants to live in flooding.
To learn more about these improvements, we interviewed U Aye Ko who is the project leader of the water control system around Kandawgyi Lake. He is an engineering geologist who dedicated his whole life to hydraulic structures and dams in rural regions.
The team consisted out of engineers, designers, hydrologists and geologists to establish this project in collaboration with the Road and Bridge Department of Yangon City Development Committee (YCDC).
Water retainment and control system
Kandawgyi Lake is an important stormwater storage within the Bahan stormwater catchment area (green lined area in picture below). It includes 7 inlets (and 1 outlet) - The inlet at the west side of the lake, near Bahan street 3, handles 70 % of stormwater flowing from the neighborhoods north of Kandawgyi Lake.
Stormwater influx at Bahan 3 inlet together with the inlet near the Japan Embassy, could before lead to overland flow as it tracks path to a lower spot in the landscape which is around Mingalar Taung Nyunt township.
Outcome of water control gates project
The water control gates are implemented at the point of Bahan 3 inlet and other crucial points such as the Japan Embassy point and U Htoung Bo point. It is to prevent extra stormwater flowing continuously to U Htoung Bo point.
So all stormwater coming down from northern part of the lake is swayed into the lake through Bahan 3 inlet. The control gate is manually controlled to prevent the water overflow at the U Htoung Bo outlet.
All excess stormwater accumulated in Bahan 3 inlet can bring those water into the lake. If the water level of lake exceeds the spillway, U Htoung Bo gate is opened and water flows towards the outside of catchment zone, and is being lead through the sewage system into the river.
This process reduces 70 % of flooding to Mingalar Taung Nyunt Township. There is still risk when it comes to heavy rain and garbage clogging alongside of the drainage which – it should be prevented.
To protect garbage entering into the river, trash remover and conveyor have been installed at the entry point of Bahan 3 inlet.
The system is better treating large quantities of stormwater - detain it and slow down its flows so it does not concentrate in locations and become floodwater.
Also this stormwater is being sent through gates to extract the pollution from plastic and other wastes that end up being transported.
Maintenance of existing culverts, a structure that allows water to flow under a road, needs to be operated in order to ease water load on one drainage. The proposed culverts are required to fully protect Mingalar Taung Nyunt Township against flood protection.