Ottawa River drainage basin
The Ottawa River drainage basin is the drainage basin in northern North America where surface water empties into the Ottawa River and adjoining waters. Spanning an area of about , it is the 12th largest drainage basin in Canada, occupying the Canadian provinces of Ontario and Quebec. It accounts for about 11% of the total Saint Lawrence River drainage area.
Murray–Darling basin
These waters are divided into four types:The two principal rivers of the basin, the Murray and Darling, bring water from the high ranges of the east and carry it west then south through long flat and dry inland areas. Nevertheless, these waters are subject to major diversions for municipal drinking supplies and irrigated agriculture that began in the 1890s. Currently, 4 major reservoirs, 14 lock and weir structures, and five coastal barrages interject the water flowing down the Murray-Darling. Of the approximately of flow in the basin, which studies have shown to be divertible, are removed for irrigation, industrial use, and domestic supply. Agricultural irrigation accounts for about 95 percent of the water removed, including for the growing of rice and cotton. This extraction is highly controversial among scientists in Australia, regarding the agriculture industry's high water use in a region extremely short of water (as much due to exceptionally low run-off coefficients as to low rainfall). These extensive irrigation systems require a reliable supply of water, not the unpredictable flows that characterize the Murray-Darling. These structures and irrigation implements were ideal when there was a steady flow of water. However, during “the Big Dry,” as the early 2000s drought came to be known, Australian farmers experienced a scarcity unlike ever before. The drought was so severe that numerous rivers and streams such as the Murray-Darling stopped flowing. The basin contains more than 30,000 wetlands. Eleven of these are protected under the Ramsar Convention of Wetlands of International Importance.