The Weber Basin Water Conservancy District (WBWCD) is investigating additional sources of potable waterfor the rapidly developing area in and around Park City in Summit County, Utah. The area is one of the majorvenues for the 2002 Winter Olympics. A preliminary evaluation of various treatment alternatives wasconducted and treatment of Rockport Reservoir water with low-pressure membranes was found to be the mostattractive alternative. A request for quote (RFQ) was issued to the membrane manufacturers and four membranesystems [including microfiltration (MF) and ultrafiltration (UF)] were selected for pilot-scale evaluation toassure a successful design and performance of the full-scale ultimate 18-million gallons per day plant. The specific objectives ofthe study were to validate the design criteria listed by each manufacturer in the RFQ response and to comparethe performance of various low-pressure membrane technologies.Three low-pressure membrane systems [US Filter/Memcor MF, Aquasource UF, Koch UF] were initiallyevaluated under cold seasonal conditions (January-March 2000). An additional low-pressure UF membranesystem [Zenon ZeeWeed UF] was then tested under warmer conditions (May-June 2000) in parallel with the MFsystem. The first phase was planned to represent worst case conditions associated with the reservoir turn-overperiod and low water temperatures. The second phase was planned to represent conditions normally associatedwith snow-melt and local runoff. Includes tables, figures.