This dataset depicts contours of estimated change in groundwater piezometric surfaces in the unconfined or uppermost semi-confined aquifers, between two specified years, by season. Contours represent change in groundwater level (elevation) by year and season (fall or spring). The contour interval is 10 ft. The contours represent lines of equal change in groundwater level surface. Positive values indicate groundwater has risen (groundwater surface elevation has increased) from the early year to the late year, while negative values indicate groundwater level surface has fallen (decreased in elevation ) from the early year to the late year. For 'Elevation' type contours, contours represent lines of equal elevation of the estimated groundwater level surface above mean sea level. Higher contour values indicate higher elevations of the estimated groundwater level. Water level measurements used for contouring are selected based on measurement date and well construction information, where available, and approximate groundwater levels in the unconfined to uppermost semi-confined aquifers.