Watershed 9 (68.4 ha) is the second largest gauged watershed at Hubbard Brook after W7.  In this case, however, there was enough room to build a very large ponding basin, and a flume was not necessary.  The metal frame in front of the V-notch in the top photo helps to support the cover that is put in place in winter.  In the bottom photo, the sheet of plywood in front of the V-notch is also part of the winterizing system.  This weir was built in 1995, much later than the other weirs, so the water record is very short.  The watershed as a whole has never been experimentally manipulated.