During the growing season, essentially April through September, much of the precipitation that falls on our state is lost through evaporation and plant uptake. Consequently, precipitation that falls during this period is generally unavailable for recharging groundwater aquifers. When groundwater levels drop during the growing season, the discharge of groundwater providing baseflow to streams also drops, resulting in decreased streamflow. Minimum groundwater levels and streamflows are generally observed in late summer and early fall, toward the end of the growing season.

Human activities during this time directly impact groundwater levels and streamflow in that the demand for water by humans is the greatest (primarily for outdoor water uses) when natural water availability is at its lowest levels. Withdrawals of water from the surface or groundwater systems for uses such as outdoor watering, directly reduce groundwater levels and streamflow and possibly change hydrology in adjacent wetlands and watercourses. Such impacts can severely reduce aquatic habitat, and may affect instream water quality to the detriment of these resources' ability to support aquatic life.
 

Therefore, as our state continues to grow, water conservation will play an increasingly important role in protecting the health of our state's lakes and streams and the safety of our drinking water.