Transmission Gully


Transmission Gully is a chain of steep-sided, isolated valleys in the Wellington Region of New Zealand, running approximately north-south between the Kapiti Coast and Tawa, through hills east of Porirua.
The gully's name comes from the 110,000-volt transmission line that formerly ran through it. The line was built in 1924, linking Wellington to the Mangahao hydroelectric station near Shannon, and later to the wider North Island transmission grid.
Despite lying mostly within the boundaries of Porirua City, Transmission Gully is sparsely populated, and most of the land is farmland, forest, or scrub. There are some areas with lifestyle blocks, particularly near Pauatahanui, and Transmission Gully is also home to Battle Hill Farm Forest Park.
In 1879 a proposed Haywards–Plimmerton Line railway route north from Wellington was to use these valleys but was never built.
The only road access through Transmission Gully is the narrow and winding Paekakariki Hill Road. Beginning at Paekakariki, it travels up and over the western ridge of Transmission Gully, and then gradually descends the western bank along most of the length of the gully to Pauatahanui.
The Transmission Gully Motorway travels through the gully and is currently under construction. It will eventually become part of State Highway 1 when it is scheduled to be completed in late 2020. The motorway was begun as part of the Wellington Northern Corridor portion of the former National Government's Roads of National Significance package of new state highways. It will not, however, offer any access to the gully itself, as no on- or off-ramps are planned to be constructed between Pauatahanui and MacKay's Crossing, north of Paekakariki.