The Waitepuia sub-catchment (of the greater Ford Rd catchment) is a small sub-catchment located between Te Puke, Paengaroa, and Maketū & Little Waihī urban settlements.
It lies on flat to gently undulating land which drains into the Te Awa o Ngatoroirangi/ Maketū Estuary (receiving environment), directly south-east of the Maketū township. The total catchment covers an area of approximately 1,179 ha. The estuary is a shallow, inter-tidal estuary that covers about 233 ha, including Papahikahawai Island.
Over 50% of the land use in the catchment is dairy farming. Horticulture (mostly kiwifruit) is the second largest land use type accounting for more than 30%. The Land Use Capability (LUC) is made up of a mixture of Class 2s (soil limitation), Class 3w (wetness limitation) and Class 3e (erosion limitation) land.
The soils comprising the lower elevation undulating land are gley soil. Gley soils exhibit high water tables in winter and impaired drainage, and are susceptible to flooding (Rijkse & Guinto, 2010). This is managed through drainage systems throughout the catchment. The other, less extensive soil types in the catchment include composite yellow-brown pumice soil on yellow-brown loam. These soils are well drained and volcanic in origin with parent materials coming from Kaharoa Ash, Taupō Pumice and more recent Tarawera Ash, making them versatile soils.
The lower Kaituna Plains (which includes parts of the Waitepuia catchment) were typical of most lowland areas and had natural wetlands (the largest wetland known as the Kawa Swamp ~ 6500ha), streams and large rivers. The majority of wetlands in this sub-catchment have been lost due to land drainage and agricultural development within the Lower Kaituna Wildlife Management Area (LKWMA). Some remnant wetlands of the once vast Kawa Swamp still remain, including Te Pourepo o Kaituna Wetland (in Ford Rd sub-catchment) and Whakapoukorero Wetland (in Waitepuia sub-catchment).
Small lateral drains were dug throughout the Kaituna Plains to help drain the waterlogged soil and allow agricultural development. This had the effect of converting lowland swamps into a series of modified stream channels. Of the 270km of waterways that flow in this area only about 20 km are relatively unmodified which have been contained between large stop banks to minimise flooding. The remaining waterways have been highly modified and straightened to drains.
The Kaituna Drainage Scheme has roughly 30-35kms of canals and drains and three pump stations in this sub-catchment, which are used to reduce flood impacts for low-lying landowners who pay a targeted rate within this scheme area.