US EPA

6501229 

Journal Article 

Color Aerial Photography for Aquatic Plant Monitoring 

Benton, AN 

1976 

Color aerial photography to detect and assess areas infested with aquatic plants was initiated in 1974 on Lake Livingston reservoir north of Houston, Texas. A. DeHavilland Beaver aircraft with two 70 mm electrically driven Hasselblad cameras was used, with Kodak Aerial Infrared Film 2443 and a yellow-orange filter, and Kodak Ektachrome MS Aerographic Film 2448 without filter. The films were developed in Kodak E-4 chemicals. Photography centered on water hyacinth and hydrilla concentrations, plus coontail and watermilfoil. The color infrared image of water hyacinth is pale to medium lavender in youth, magenta in maturity, deep red-brown in late season, and green-brown with the onset of senescence. The effect of 2,4-D BEE is clearly seen on color infrared film. An initial green-brown change is noted, followed by lightening to brown and tan. If herbicide treatment is stopped, regrowth almost always occurs, starting with lavender and darkening to magenta and rust-red. Normal color film was of much less value than the infrared. Differentiating submersed species with color photography proved more difficult than for emersed species, but was still useful. (Lynch-Wisconsin) 

; Aquatic weed control; Aquatic plants; Remote sensing; Aerial photography; Monitoring; Water hyacinth; Reservoirs; Films; Texas; Cameras; Herbicides; Nuisance algae/