The Upper Grand Watershed (HUC 04050004) covers an area of approximately 4,070 km² in Ontario, Canada. The watershed is characterized by a variety of land uses, including urban, agricultural, and natural areas. The hydrology of the watershed is dominated by the Grand River, which is the primary source of surface water. The watershed experiences a significant snowpack during the winter months, which contributes to spring flooding. The surface water in the watershed is also impacted by reservoirs, which are used for hydroelectric power generation and water supply. The water quality in the watershed is generally good, but there are concerns related to nutrient levels and bacteria contamination. Interesting climatic facts include the frequent occurrence of severe winter storms and the increasing frequency of extreme weather events, such as heavy rainfall and flooding. Trends in the watershed include population growth and increasing urbanization, which are putting pressure on the natural resources and water quality in the area.