This section of the headwaters of the Werribee River is situated in largely cleared hilly land, with a number of creeks commencing on slopes below the Blackwood Ridge Road. The Kurweinguboora Creek flows from near Blakeville and water is stored in it at the Colbrook Reservoir, which provides drinking water for the township of Ballan to the south.
The Kurweinguboora Creek continues down through hills on its way southwards and meets the Korjamnunnip Creek (also known as Pykes Creek), and then flows into Pykes Reservoir. Dale Creek flows into the reservoir at the north-east corner. All of these creeks once flowed across fertile flats before joining the Werribee River downstream of the dam wall.
Supplementing the flows into the Pykes Creek reservoir, are flows from the upper Werribee River which are piped through a tunnel from a diversion weir on the Werribee River downstream from Ballan, into Myers Creek flowing then into the southwest corner of Pykes Creek reservoir.
“The Werribee River Weir and diversion tunnel were constructed between 1916 and 1918 to divert flows from the Werribee River to Pykes Creek Reservoir via Myers Creek. The weir and tunnel entrance is located on the Werribee River approx. 2km east of Ballan. The tunnel is 1.8m in diameter and 1.5kms long. It opens into Myers Creek on the east side of Monteville Lane and the water then runs along Myers Creek.” 1
The exit point of the tunnel is quite close to Monteville Lane just over the fence line, but is often obscured by long grass, and so the minor to moderate erosion possibly caused by these flows in an otherwise ephemeral creek is difficult to see. See map of the Pykes Creek Reservoir and the Werribee River Water Supply Catchment.
The Pykes Creek flows are then released below the dam wall, and flow back down Pykes Creek and join the Werribee River downstream.