«Report prepared for Environment Canterbury by R E Reid (Consultant) M Surman March 2014 With update notes February 2015 Ashley River Rating District: ...»
Ashley River Rating
Report No. R14/28
ISBN 978-1-927299-27-2 (print)
978-1- 927299-28-9 (web)
Report prepared for Environment Canterbury by
R E Reid (Consultant)
With update notes February 2015
Ashley River Rating District: Targeted rating classification review
Table of Contents
1 Executive Summary
1.2 Operations and maintenance funding
1.4 Summary of recommended changes
2 Rating differential issues
2.3 Pegasus Town
2.6 Existing Class A
2.7 Existing Class B
2.8 Existing Class C
2.9 Existing Class D
2.10 Extension of district upstream
2.11 Rural area south of existing rating district
2.12 Recommended classes
3 Effect of making the recommended changes
3.1 Summary of impacts on rating
3.2 Effects of modifying recommended changes
Appendix A - Background information
Appendix B - Map of Existing Ashley River Rating Classification Map.............. 28 Appendix C - Map of Existing Waimakariri-Eyre-Cust Rivers Classification...... 29 Appendix D - Flood Modelling Example
Appendix E - Map of Proposed Ashley River Rating Classification
List of Figures Figure 3-1: Existing rating classification map
Figure 3-2: Proposed classification map
AppendicesFigure A1: Rating classification map
List of Tables Table 3-1: Existing Ashley River Rating District Targeted Differential Rating
Table 3-2: Proposed Ashley River Rating District Targeted Differential Rating
Table 3-3: Comparison of existing and proposed rates
Table 3-4: Comparison of existing and proposed rates if the rating district was not extended south of its current boundary
Appendices Table A 1: Existing Ashley River Rating District Targeted Differential Rating
Table A 2: Rates $/$100,000 CV - 2013/14 incl GST
1 Executive Summary The basis for apportioning benefit and collecting rates to fund the operations and maintenance of the Ashley River Protection Scheme is the classification adopted in 1957 under the Soil Conservation and Rivers Control Act 1941.
With the development of Pegasus Town, and an improved understanding of flood risk based on recent floodplain computer modelling work, the question has been raised as to whether the rating district area boundary, and the relative weightings of the different rating classes within that area are appropriate and equitable.
1.1 Rating Current rating legislation is the Local Government (Rating) Act 2002, as described in more detail in Appendix A, section A2.
This Act provides for targeted rating, either uniform or differential, and sets out matters that may be used to define categories of rateable land (including capital value), and factors that may be used when calculating liability for targeted rates (including extent of provision of service). The matters and factors used must be identified in the rating authority’s annual plan.
The Local Government Act 2002 provides that the funding needs of a local authority are met from the sources that authority determines appropriate.
In relation to each activity to be undertaken, the authority is required to consider;
• Community outcomes the activity provides,
• Distribution of benefits from the activity,
• Actions causing a need for the activity,
• Period over which the benefits occur,
• Costs and benefits of funding the activity separately from other activities,
• Overall impact of any allocation of rating on the well-being of the community.
1.2 Operations and maintenance funding The river control works on the Ashley River are designed to protect properties downstream from the Okuku River confluence, and on both the north and south banks of the river, from floods up to 2400 cubic metres per second (estimated return period of 1 in 50 years and annual exceedance probability of 2%).
These works have been progressively constructed by former authorities since about 1900. The responsibilities, assets, and powers of the former authorities were transferred to Environment Canterbury in 1989.
In 2003 the Waimakariri District Floodplain Management Strategy was adopted, which includes a policy to increase the flood capacity of the Ashley River to 3,000 cumecs (estimated return period of 1 in 100 years and annual exceedance probability of 1%). Most of the river system now has this capacity.
Operation and maintenance of the flood protection system is funded by a mix of rates, and income from reserve lands set aside for that purpose. The rating income is made up of general, works and services, and targeted rates (refer Section 7). The targeted rates are based on property capital value, Several footnotes in this report update the report to reflect the proposal adopted for the draft Long Term Plan 2015/16.
and a 1957 differential classification of expected relative benefits from the works (consisting of six benefit classes within a defined area).
Flood damages will impact on floodplain development. Capital value is therefore an appropriate basis for rating. Capital value also has the advantage of maintaining relativity between properties over time, as it reflects new development and changes in land use. For example, if the rate of urban development and increase in value exceeds the rate of rural development and increase in value, a higher proportion of the targeted rates will be collected from the urban areas.
The flood protection works give differing levels of direct benefit to properties, depending on the prescheme flood risk, the type of property development, and standards of flood protection work. Flood protection also gives indirect benefit, such as protection from damage to community infrastructure, disruption to transport and communications, and economic and social disruption, as well as providing opportunities for enhanced recreational use.
All these elements are taken into account by using a targeted differential rating system, which can include a class for indirect benefit, and provide a level of funding from wider sources through works and services and general rate contributions.
1.3 Conclusions The Capital Value basis used for rating is appropriate for river control activity, and for the Ashley River Rating District, and complies with the requirements of the Local Government (Rating) Act 2002.
It is considered that the rating classification currently used for the Ashley River Differential Targeted Rating District should be updated.
Differentials applied to the targeted rates are intended to be in proportion to the benefits received from
the activity being funded. This is not considered to be the case for the existing classification because:
• There are areas rated at lower levels than is supported by historic observations and recent flood modelling work, particularly for the Rangiora urban area.
• There is an area between the existing classified area and the Waimakariri River (North Kaiapoi & Flaxton) that can be affected by Ashley River flooding, but for historic reasons (legislation applying at the time) was not included in the Ashley classification.
• There are areas rated at a higher level than is supported by recent flood modelling work, including the area being developed as Pegasus Township.
• As Pegasus Township is developed, the inequity of the high level of rating of this area will increase.
• There is an area along the Ashley River south bank between Sunken Road and the Okuku River confluence, that benefits from stopbanking and bank erosion protection works, and is currently not rated. The rating district should be extended to include this area.
A draft proposal is discussed in Section 2 and modifications to the proposal are discussed in Section 3.
The impacts on rates for the 2013/14 year are summarised in Section 3.1 (and Section 3.2 for the situation if there is no extension of the rating district to the south).
Note that there are differences between the draft proposal discussed in this report and the proposal presented in the 2015/16 Long Term Plan. In particular, for the Long Term Plan, the existing rating boundary has not been extended to the south, the urban boundaries have been adjusted to include areas zoned for future urban development, and rates comparisons have been updated to 2015/16 proposed rates.
While there are differences of detail and exact amounts for individual properties, there are no significant differences between the rates comparison presented in Table 3.4 and the proposal in the draft 2015/16 Long Term Plan.
1.4 Summary of recommended changes
The report concludes that for:
• The Fernside, Kaiapoi and Flaxton Swamp areas There is a flood risk to Kaiapoi and Flaxton from the Ashley River, and water could pond to significant depths in parts of Kaiapoi and the Flaxton swamp. These properties are paying Class A or B Waimakariri-Eyre-Cust rates in recognition of their risk from the Waimakariri, Eyre, & Cust rivers, and should also be included in the Ashley River rating district. The modelling has also shown a strip of land through Fernside that receives benefit from the Ashley River stopbanking system.
• Rangiora Most of Rangiora was assessed as Class F for indirect benefit. This classification is considered too low. The modelling shows most of Rangiora is at risk, albeit relatively low risk, from flooding from the Ashley River. It was observed in the 1951 flood that floodwaters only had to rise 300mm to enter Rangiora via Ashley St.
It is recommended for Rangiora that the existing Class F should be increased from 6 to 12 points of benefit, the same relative benefit which is recommended for Pegasus, Woodend, and the area of Kaiapoi adjacent to the Cam River. The extent of this class should be widened to the current urban extents.
• Pegasus Town The area currently being developed for Pegasus Town is within Class A for the current rating classification. With the exception of a small area at the north eastern corner of the Pegasus Town site, both the flood modelling, and maps and reports of historic flooding, indicate that the site does not have a high flood risk. A more appropriate classification would be the same as for Rangiora Town, with a relative benefit of 12.
• Woodend Woodend is a developing urban area and in any review should be put into a separate class which allows easy adjustment as new development occurs. Woodend is currently in Class D, relative benefit 12. The recommended relative benefit is 12.
• Existing classes Modest changes to the existing classes are recommended, including amalgamating Classes B and C, adjusting the relative benefit to 20 (from 24 and 18 respectively), and increasing the relative benefit for the existing class D from 12 to 15. Based on the modelling, this should result in a fairer reflection of the benefits the flood protection and control works provide.
Effects of making the changes suggested.
To raise the same targeted rates as in the 2013/14 year, assuming the 2013 level of development of Pegasus Town, and with the area of Flaxton and Kaiapoi North of the Waimakariri River added to the
classified area, the effect on rating would be as shown in the table below:
1.5 Recommendation It is recommended that Environment Canterbury commence consultation on the revised Ashley River Rating District targeted rating system, with the objective of implementing any change in the 2015/16 year. Changes should appropriately reflect the relative benefits received from the Ashley River Control Scheme works.
2 Rating differential issues
2.1 General The basis for apportioning benefit and collecting rates to fund the operations and maintenance of the Ashley River Protection Scheme is the classification adopted in 1957 under the Soil Conservation and Rivers control Act 1941.
With the development of Pegasus Town, and an improved understanding of flood risk based on recent floodplain computer modelling work, the question has been raised as to whether the rating district area, and the relative weightings of the different rating classes within that area, are appropriate and equitable.
The existing rating classification is a differential system based on capital value. Capital value, as distinct from land value or land area, is considered to be the most suitable basis for rating for the Ashley River District. The Ashley River Control Scheme objective is to reduce flood damage and erosion. The cost of damages due to flooding and erosion are related to value of the capital developments on the land.
The classes adopted in the existing (1956) classification were generally based on assuming no river
control works or stopbanks and considering the relative benefits derived from the works:
Class A - Flooding every 15 to 20 years Class B - Land protected from erosion Class C - Flooding every 20 to 25 years Class D - Flooding every 100 years Rangiora - Complete flooding too remote to consider, light flooding every 50 to 80 years A small Class E (with no description) was subsequently added during the hearing and appeal process in 1957.
Modern subdivisions are often built with raised ground levels to account for flood risk. Building levels assume a breach in the stopbanks but not an absence of stopbanks. With no stopbanks these areas would often be at greater risk from flooding. The classification is based on the benefits the flood protection system provides.
The areas getting benefits from the construction, operation and maintenance of the river control works
have been reviewed as follows: