Water levels are expected to rise along the Ottawa River in the Ottawa-Gatineau area over the next two days due to the heavy rain in the forecast. Environment Canada has issued a yellow warning – rainfall for Ottawa, calling for 30 to 50 mm of rain tonight and on Thursday. The Ottawa River Regulation Planning Board says while water levels are “stable or slightly declining” on the Ottawa River, rain is expected to add “more water” to the river this week. “Forecast rain starting today is expected to add more water from the northern and central unregulated areas, with quantities depending on how much rain falls and where over the next few days,” the planning board said. “This could lead to water levels and flows increasing gradually in all locations over the next few days.” Officials warn a “second flood peak remains possible” along the Ottawa River, from Pembroke to Ottawa and Gatineau and to Montreal. “A rapid melt combined with rainfall could lead to water levels higher than those observed between April 19 and 22 in all locations,” the board said. According to the Ottawa River Regulation Planning Board, water levels dropped one centimetre at Gatineau on Wednesday and remained steady at Britannia. Water levels also remain steady in the Fort Coulonge and Arnprior areas. The forecast for the Ottawa River calls for water levels to increase five centimetres at Ottawa and Gatineau on Thursday. The Ministry of Natural Resources said on Wednesday the flood warming will remain in effect between Pembroke and Arnprior until May 6. “Recent rainfall combined with warm temperatures has resulted in the melting of the snowpack and lake ice,” the ministry said in a statement. “This combined with forecasted precipitation and continued warm temperatures, will result in high water conditions as the freshet runoff moves through the system. This combined effect has caused the water levels and flows of the Ottawa River to rise significantly and may continue to remain above flood levels in flood prone locations throughout the week and into next week.” Second flood peak in Gatineau Officials in the City of Gatineau are warning residents that a “second flood peak cannot be ruled out.” “Residents are encouraged to take advantage of the reopening of certain flood-prone streets to local traffic to stock up on supplies and obtain sandbags, if needed,” the city said on Tuesday. “Depending on the projected water levels, some streets could be reclassified and closed to traffic again.” Officials warn the heavy rain in the forecast could cause water levels to increase. “With the new forecasts, I urge residents to remain vigilant and take advantage of this respite to prepare if needed,” Gatineau Mayor Maude Marquis-Bissonnette said in a statement. “The City is here for you: our teams remain fully mobilized.”