74 Waikanae River Environmental Strategy 12. Arapawaiti/Otaihanga Reach
Figure 12: Arapawaiti/Otaihanga Reach 75 PART C: Protecting and Improving the River Corridor / Arapawaiti/Otaihanga Reach
Waikanae River Environmental Strategy 12.1 Situation On the north bank, this reach extends from Te Aorere Reach to the point where the dune comes close to the river (river cross section 50). This dune defines the inland part of the river, from the open estuary landscape. This area, from the channel that runs in from El Rancho is part of the Waikanae Estuary Key Native Ecosystem (KNE). is working in partnership with and DOC to protect the biodiversity values inherent in this area. There is a backwater area with some wetland plants - this is an oxbow in a former river meander (XS 95, north bank). A significant restoration project has been undertaken to restore the area s ecological values and enhance habitat for whitebait spawning. Weed control on the northern bank has not only included protecting the estuarine edge, but in partnership with has also extended ecological weed control well beyond this area to include the riparian margins, dune faces, and dune slope buffers in this area. In addition, the have been working with FWR and KERMT in controlling ecological weeds and restoration planting around the Northern Oxbow with assistance of the Ministry of Environment funding. On the south bank, the river berm is bounded at the upstream end of the reach by Otaihanga Domain, which has a parkland character. Further downstream, the river berm is narrow and is bounded by the main residential area of Otaihanga. At the lower end of the reach the tidal influence in the river marks the end of riverbank willow plantings. The Otaihanga oxbow (south bank) and surrounding land has high conservation values, as well as playing an essential role in flood risk management as a water storage area. Te Atiawa ki Whakarongotai note that this reach is of particular cultural significance as there are various mahinga kai sites and taonga species populations. There are also several wahi tapu sites in this area. The riverbanks and the oxbow in this reach of the river are spawning grounds for Inanga (whitebait). Therefore, it is important that suitable conditions for spawning are maintained or enhanced. The Ecological Strategy identifies the Arapawaiti site in this reach. The Arapawaiti site comprises both banks, but mainly the northern bank between the old cut-off meander downriver to the high dune. The Ecological Strategy notes that the diverse mosaic of natural estuarine landforms (namely the prominent high dune and two unique wetland habitats being the lagoon and an oxbow) have potential for ecological restoration. 79 12.2 Progress Recommended actions included the protection of the Oxbow as an ecological area, rather than a recreational area. In 2009, the FWR obtained funding from the DOC s Community Conservation Fund for the restoration of the Oxbow. This has contributed to achieving the recommendations from the Ecological Strategy regarding protection and the 2009 Strategy regarding restoration initiatives in this location. Kāpiti Coast District Council and KERMT have since also become involved in the restoration of the Oxbow. have upgraded the culverts between the river and the oxbow, to increase water levels. The Management Plan for Otaihanga Domain was reviewed by in 2004. The Otaihanga Local Outcomes Statement was published in 2004 and updated in 2009. This contains recommendations relating to the Otaihanga domain and boating club, as well as recommendations relating to other sections of the river. North bank oxbow has recently been restored 76 79 Park, G, 1999, p. 27.
12.3 Vegetation Management On the north bank the oxbow at XS 95-105 has high ecological values and is being restored by and community groups. The local residents value the pines alongside the riverbank for their visual quality, shelter, and roosting habitat for birds. The pines do, however, affect visual access between the oxbow and the River Corridor. This in turn masks the oxbow s role as part of the river system. As part of the Oxbow restoration project, some of these pines have been removed as part of preparation for planting of species native to the area. The semi-rural parkland character of Otaihanga Domain on the South bank is to be maintained. 12.4 Access The shared path on the north bank links Weggery Drive with Makora Road on the south bank via the suspension bridge across the river at Otaihanga Domain. The oxbow area on the north bank has a service vehicle bridge near the western end and a concrete pipe on the eastern side. Pedestrian only access on the south bank links the Otaihanga Domain with the Otaihanga Boat Club, which will eventually connect up to the Waikanae Estuary walkways. Horse riding is prohibited within Otaihanga Domain. Signage at the Domain directs horse riders to the end of Makora Road and around the eastern perimeter of the Domain to Makora Road. Access to the river over private land from there has been formalised with signage in consultation with the landowner. Horse access to the south bank bridleway is now via the official bridleway link from Makora Road at the eastern boundary of the Otaihanga Domain. Otaihanga Domain and oxbow 12.5 Recreation Facilities The Otaihanga Domain Management Plan (2004) covers management of Otaihanga Domain. Additional recreation facilities are not envisaged on the north bank, as the Waimanu Lagoon and beach in the next reach are the principal focus of recreation on this side. This side of the river should be kept principally as a walking area with natural values. 12.6 Interpretation Interpretation of the wetland habitats and restoration project at the Oxbow has been erected on the north bank. 12.7 Flood Risk Management A floodwall has been constructed at Otaihanga Domain, along its southern edge. Bank edge protection using rock rip rap was used on the south bank near the boating club, along with some river realignment works. On the north bank, a River Corridor Flow Path has been identified between XS 175 (in the upstream reach) and XS 90. On the south bank, a River Corridor Flow Path has been identified between XS 90 and XS 100. Any new planting in these areas should be restricted to low lying grasses and flaxes to prevent blockages to flood flows, and Flood Protection must be consulted during the planning stage. (See Appendix 1). PART C: Protecting and Improving the River Corridor / Arapawaiti/Otaihanga Reach 77
Waikanae River Environmental Strategy 12.8 Recommended Actions for This Reach 12.8.1 Vegetation Management River cross section (XS) Recommended Actions 80 Parties Involved North bank 95 Protect the oxbow as an area of ecological significance, not a recreational area. Investigate, and where suitable, implement methods to improve whitebait spawning habitat 95 When the pines come to the end of their life, do not replant so that the oxbow has a more evident relationship to the river. Gradually replace the pines around the oxbow with suitable large natives. 90-175 Ensure that River Corridor Flow Paths are preserved. River cross section (XS) Recognise the particular significance of this area for tangata whenua and their interest in the in the management of this reach (see Section 2 of this Strategy) South bank Foster an understanding of revegetation objectives and weed problems that can arise from garden rubbish and garden escapes for private landowners. Investigate and where suitable implement methods to improve whitebait spawning habitat. Private Landowners 90-100 Ensure that River Corridor Flow Paths are preserved. Recognise the particular significance of this area for tangata whenua and their interest in the in the management of this reach (see Section 2 of this Strategy) 105 Investigate methods for reducing the contaminant loading in water discharging from the holiday park duck pond and Bridge Pond (located immediately north of the Otaihanga bridge). 12.8.2 Access River cross section (XS) Recommended Actions Parties Involved 70-90 Upgrade shared path on north bank to commuter standard between Weggery Drive and the suspension bridge to asphalt or concrete surface 78 80 Both the Environmental Strategy and Ecological Strategy support these recommendations.