2.2 Project Issues
Project Watershed is Council’s response to a complex set of issues that arises from the diversity of the catchment. The issues Project Watershed addresses are summarised below:
- The historic system for financing flood protection systems in the Waikato/Waipa catchment is unable to fund maintenance into the future, due to:
Without an adequate funding system, existing catchment and flood control scheme assets and associated land drainage systems will deteriorate. This in turn will cause land productivity to decrease, increase flooding of rural and urban areas, and lead to a drop in land values.
- the variability and inadequacy of the present rating system
- the need to fund depreciation
- the potential withdrawal of Government assistance, and
- the accumulation of operating debts.
- Current legislation requires recognition of wider beneficiaries and contributors to the need for work, other than the historically recognised landowners who directly benefit.
The lower Waikato flood plain is affected by the past actions of land owners, and power generators and their continued use and operation. The effects of these influences are to increase the height and severity of flood waters and reduce the length of flood peaks. This affects downstream rivers and channels and necessitates higher flood banks, with higher drainage pumping costs to landowners and affected urban centres within the Waipa and lower Waikato flood plains.
While some of these effects were historically recognised in separate funding agreements with Government, these agreements may lapse mid 2003. These historic contributions need to be reassessed and captured in a new rating system which maintains equity.
Pastoral farming increases the speed and severity of runoff. This effect has not been recognised in the historic rating system - an inequity that current legislation requires Environment Waikato to consider in any new rating system.
Major urban areas also increase the speed and severity of runoff, with similar effects to the increase of runoff from pastoral land use. While the percentage of the catchment covered in urban development is small compared to that covered in pastoral development, the intensity of urban runoff is significant.
- Management of soil conservation, flood control, land drainage and water quality are strongly interrelated activities. When activities in one part of the catchment are managed in ways that are incompatible with activities in other parts of the catchment, inequities and inefficiencies are created.
The historic inconsistencies in creating flood management works and other flood management provisions have resulted in a wide range of standards of protection throughout the catchment. In a number of areas, the present levels of protection are not sufficient for present and future needs and additional protection has been requested. For example, residents in parts of Turangi and Tauranga - Taupo are threatened by flooding, but there is currently no suitable funding mechanism in place to meet the cost of protection.
- Flood protection systems create an opportunity for improved land drainage, and therefore a need for either gravity or pumped outlets as part of the protection works. Inappropriate development or management of land drainage systems can compromise the effectiveness of flood bank systems and flood outlets.
- The success of the Lower Waikato flood protection system depends in part on maintenance of the riverbed below natural levels. Uncontrolled erosion within the larger catchment threatens the integrity of the system over time.
- Accelerated erosion affects both local landowners and the downstream river system. Significant areas of the steeper upper catchments of the Waikato and Waipa rivers are vulnerable to erosion. These areas include pumice sands of the Taupo and Upper Waikato, the headwaters and ranges of the Waipa River, and hill ranges of the Lower Waikato.
Landowners in these areas are affected by loss of soil and erosion or damage on their properties. This erosion also puts sediment and debris into local streams, and into downstream rivers and lakes. This increased sediment and debris (including silt, sand, rocks, trees and other debris) can silt up channels downstream, and cause further erosion, instability and damage to streams and rivers. It also lowers water quality, and affects fish and in-stream values
Accelerated erosion is the result a complex set of factors, not all of which can be fairly laid at the door of the site landowner. Erosion low in any catchment, for instance, is exacerbated by the cumulated runoff from land higher in the catchment, which in turn is exacerbated by land use in the upper catchment. The beneficial effects of reducing river and stream sediment almost inevitably spread to landowners and communities downstream. Erosion control on the banks of unstable major rivers and streams can be very expensive and often beyond the resources of individual landowners.
- Increased community recognition of the value of our rivers and streams requires that greater attention be given to water quality issues, including sedimentation.
- Effective and efficient management of river and stream morphology is not occurring in many instances, due to fragmented and inconsistent efforts being made by individual landowners.
- Effective management of rivers and streams through the Waikato catchment requires greater integration and coordination.