Time line of dam construction and operational changes for the Pak-Mun dam 1994–2011.

The right-most column indicates whether the river flow rate upstream of the dam (near the sampling area) is likely to have been affected during the active phase of the Neotricula aperta life-cycle of that year (i.e., the low-water period March to May); the low-water target elevation of the upstream waters at the dam site was 105.5 m (MSL). Sources [1], [15].
*The dam being open in June would have prevented the more rapid and unnatural termination of the low-water period (and activity of N. aperta), which would have occurred under the usual dam operation policy.