It turns out that we have had to turn the lake pumps off to stem the water flow and also turn off more than one valve due to the 10 inch waterline that was broken. This means that everyone on the system may experience a lack of water and/or water pressure.
The good news is that we have a length of replacement pipe available. We expect that the repairs can be completed within 2-3 hours, at which time the pumps will be turned back on and water service restored to all properties.