In the late 1970s and early 1980s, the New York State Department of Transportation (NYSDOT) was involved in selecting geotextiles to be used in a turbidity curtain being designed by consulting engineers for the NYSDOT proposed replacement of the West Side Highway in New York City. The proposed designs involved dredging material from the Hudson River and constructing an embankment in the river over an approximate length of 4.5 km (2.8 mi), extending approximately 183 m (600 ft) into the river. The project's Water Quality Certificate required that turbidity curtains be placed along the US Pierhead line, totally isolating the areas of dredging and filling operations. It was determined that a turbidity curtain of the depth required to comply with the Water Quality Certificate had never been constructed in a tidal estuary. It was therefore decided to develop a laboratory test program followed by the on-site installation of a 180-m (600-ft) long prototype turbidity curtain. Both programs were aimed at supplying data to be used in the design of the actual turbidity curtain. Details of the testing program, design considerations, and conclusions reached from the prototype installation are given. Because of environmental concerns, however, this project was not constructed.