In the summer, levels are regulated to provide reserve capacity sufficient to contain moderate runoff. No Navigation Severe Damage to Critical Habitat Rule curves are the historical compromise for water level management that have been established to balance competing interests for target water levels. Within that range, navigation levels and municipal water supply are given the highest priorities to ensure a stable, reliable water supply throughout low water summer months. Critical habitat concerns also drive target levels toward the high side of the range to ensure against damage to delicate natural resources. In order to avoid floods, demand for high levels must be balanced against the effects on property owners.
Heavy fall rains before the winter freeze.
At the close of the navigation season, water levels are drawn down for storage capacity anticipating spring runoff. The lowest water level on the system can be achieved mindful of water supply needs. Competing needs must be balanced with the available water supply. DEC is New York State's flood plain management agency, which provides technical assistance to the state's 1,500 flood-prone communities to help them prevent loss of life and to mitigate flood damages. DEC and SEMO work together to train community response teams by providing instructional materials, tests and drills, and evaluation of local training programs.