Monitoring Aquatic Plants in Reservoirs

Noxious aquatic plants in reservoirs and in irrigation canals reduce property value and recreational potential, increase evapotranspiration losses, restrict navigation, increase water treatment costs, and diminish the free flow of water. In support of aquatic plant control efforts in Texas and Oklahoma, studies were conducted of the cost and capability of sequential aerial photography for detection, delineation, and discrimination of the several exotic species now infesting reservoirs in both states. Seasonal photography with color infrared film was found to be an accurate, efficient method for detecting new outbreaks, for mapping, by species, the extent of infested areas, for monitoring the results of control work, and for defining overall aquatic plant control strategy. Aerial photographic monitoring costs, a function of desired scale, format size, and frequency of photography, are relatively low compared with the total cost of an effective, state-run aquatic plant control program.