Meredith #4 Diversion phase 2
In 2015, the Meredith #4 Diversion replaced an existing rock diversion with an engineered rock riffle diversion. At that time the existing diversion was left in place to allow the landowner to irrigate in 2016, as the fish screen was not able to be installed. The Meredith #4 Diversion Phase II removed the vacated rock diversion downstream from the new diversion structure installed in 2015 and regraded the channel.
Photo of the Meredith #4 diversion before work had begun to remove it. The diversion consisted of railroad iron driven into the streambed which held boards that were never removed and were supported by large rip rap. Over time the hardened diversion accumulated sediment in combination with increasing velocity and scour behind it, causing the fish passage barrier seen in the photo.
This photo is showing the low ground pressure machine that was used for the removal of the existing structure and the replacement of the structure with a low sloping rock riffle to allow fish passage. The overall elevation of the stream at the location of the diversion was lowered approximately 1 foot, and an apron was created with a combination of imported material and leftover rock material from the existing structure.
Photo showing the previous location of the diversion structure after it was removed. A low sloping, roughened riffle was constructed and vegetation was saved and replanted on the streambanks.