The Grand River Conservation Commission was the first watershed management agency in Canada when it received its formal Letters Patent in August, 1934. This was the first time local municipalities had banded together to address water management issues on a watershed scale. The founding partner municipalities were Brantford, Galt, Kitchener, Fergus and Caledonia. William Philip of Galt was the first chairman, and the Commission's head office was in Brantford. Other municipalities soon joined the partnership.

"During the Depression, the federal and provincial governments were more interested in helping people by providing government relief. But the tide was turning: governments were thinking about large-scale public works projects that would provide jobs and help the economy. The federal government’s National Employment Commission supported a proposal for a dam across the Grand River. By April 1938, the province and federal government had each agreed to contribute 37.5 per cent of the project. This left the municipalities to cover the remaining 25 per cent, an amount they could manage. This was divided among the municipalities differently based on tax assessment and benefits such as water supply, flood protection and sewage disposal. A second Grand River Conservation Commission Act was passed by the province in 1938 to broaden the commission’s responsibilities so it could manage the construction projects."

In 1942 the Commission completed the Shand Dam near Fergus, the first dam in Canada built for flood control, water supply and water quality purposes. This was followed by the Luther Marsh Dam in 1954 and the Conestogo Dam in 1958. The Commission also planted more than two million trees on their land and undertook some of the province's first large scale reforestation projects.

The success of the Commission, its watershed scope and municipal partnership model led to the Guelph Conference on Conservation in 1941, and the Conservation Authorities Act of Ontario in 1946. This new act led to the creation of 36 conservation authorities across the province. In fact, the commission supported the creation of the Grand Valley Conservation Authority in 1948 and the two organizations — the GVCA and GRCC had the same chair, William Philip of Galt. They amalgamated in 1966 to form the present day Grand River Conservation Authority and are the two founding organizations of the Grand River Conservation Authority.