Farmers should also store as much rainwater as possible and use it efficiently, said Agriculture Minister Chalermchai Sree-on on Monday.
"We cannot tell how many storms will hit Thailand this year, but we have ordered RID to prepare personnel and drainage equipment to deal with upcoming issues," he said.
The rainy season will last from mid-May to mid-October, according to the Thai Meteorological Department. It forecast continuous rain across the country this week, with isolated heavy showers in the South.
Chalermchai said the Department of Agricultural Extension is drawing up a plan to grow crops that use less water, such as corn for animal feed. He expects to see the finished plan this week.
"The ministry also asked the Rice Department to seek effective rice species, and the Commerce Ministry to find new markets, such as in the Middle East," he added.
He also asked farmers to cultivate crops that would keep agricultural product prices low.
Meanwhile, RID director-general Prapit Chanma said water management during the drought season went as planned. Thailand has 19.95 billion cubic metres of water reserved for the rainy season, higher than the targeted 15.55 billion cubic metres.
The rainy season is expected to bring lower rainfall between June and July and heavy rain from August and September, he said.
"The department is cooperating with provincial agencies to monitor the water situation and prepare equipment, such as water pumps, excavators and tractors," he added.
The Thai Meteorological Department also warned people in upper Thailand to look out for thundershowers and isolated heavy rain, adding farmers should protect their crops. Meanwhile, the South will see heavy rain that may bring flash floods.
"All ships should proceed with caution and keep off thundershowers today [May 10]," the department added.