Background and Explanation
Purpose of River and Lake Beds Module
This module of the Regional Plan addresses river and lake bed management issues and is divided into three chapters. Chapter 4.1 provides a general overview of river and lake bed management issues, including what issues Chapters 4.2 and 4.3 address, relevant sections of the RMA, a brief description of the adverse environmental effects of concern and the relationship of Module 4 to other chapters of the Plan.
Many structures on, in, under or over the beds of rivers and lakes provide for transport and communication, prevent or reduce flooding, generate electricity and provide for recreational use of water bodies. Chapter 4.2 deals with the use, erection, reconstruction, placement, alteration or extension of structures in, on, under or over the beds of rivers and lakes and any associated disturbances of the beds under s13 of the RMA.
Chapter 4.3 addresses those activities which involve some form of disturbance to the beds of rivers and lakes. Disturbance of the beds of rivers and lakes is necessary when constructing, maintaining or removing a structure, or maintaining the integrity of dams, diversions and drainage districts and river control schemes. Disturbances may include sand and gravel extraction, construction activities, bed maintenance, vegetation removal, dredging and reclamation. Disturbances directly associated with the erection, reconstruction, placement, alteration or extension of any structure is addressed in Chapter 4.2 of this Plan.
This Plan only applies to drains where they are natural or modified watercourses*. Drains that are artificial watercourses* are not included in the definition of a river under the RMA and are therefore not subject to the requirements of rules in this module of the Plan.
This module also applies to wetlands where the wetland becomes part of the bed of the river when the river is at its fullest flow, or part of the bed of the lake when the lake reaches it highest level without overtopping its margins. Also cave passages that are either ephemeral or permanently flowing water bodies are considered to be a river bed.
A wide variety of structures and bed disturbance activities occur in, on, under or over the beds of the rivers and lakes in the Waikato Region. Structures range from the large hydro dams on the Waikato River, and flood control structures on the Waikato, Waipa, Piako and Waihou Rivers, to bridges, culverts, maimai, whitebait sands, telephone or power cables over rivers and lakes, and jetties and moorings on many other rivers. Bed disturbance activities include sand and gravel extraction, construction activities, dredging, and vegetation removal for flood control and drain maintenance purposes.
Many of these structures are important for the provision of transport, communications, electricity generation and supply, gas supply, flood protection and recreational activities. The beds of rivers and lakes are a supply of sand and gravel for individual and industry needs. Disturbance of river beds is necessary to maintain river systems to ensure the efficient functioning of river and drainage control systems and structures associated with electricity production.
RMA Provisions and Interpretation
Explicit provisions relating to the management of river and lake beds are found within s13 of the RMA. Section 13(1) relates to structures, disturbances, planting and deposits on river and lake beds, while s13(2) relates to passage through and removal of plants on river and lake beds. The presumption within s13(1) is that activities cannot be carried out unless they are allowed by a resource consent, or a rule in a regional plan or any proposed regional plan. Section 13(2) has the opposite presumption, with activities allowed unless they contravene a rule or rules in a regional plan or proposed regional plan.
The following diagram of a river bed is included for guidance only to demonstrate where the requirements of s13 of the RMA apply
For the purposes of the rules in this Plan in those situations where the top of one side of the bank is higher than the other side, the top of the bank referred to in conditions on rules is interpreted as being the top of the lower bank, e.g.
Adverse Effects of Activities
Destabilisation of river and lake beds is a natural process. However, destabilisation of the beds of rivers and lakes can be exacerbated through inappropriate instream constructions, fluctuating water levels, sand and shingle removal, inappropriate removal of bank vegetation, surface water activities, such as jet boating, and plant and animal pests. Inappropriate land uses, such as livestock grazing on lake or river banks, may also cause instability through vegetation removal, treading damage and catchment modification.
Destabilisation of the beds of rivers and lakes may have adverse effects on water quality through increased transport of sediment and deposition causing damage to aquatic habitats. Destabilisation may also cause changes in the course of rivers and streams, resulting in loss of land, damage to property and damage to infrastructural assets such a roads, bridges, flood protection and drainage works.
Structures on the beds of larger rivers and lakes may obstruct navigation. Care needs to be taken to ensure that structures are not positioned where they may obstruct navigation. A navigable river is considered to be one where the width at the top of the channel is greater than 10 metres. Rivers with a top of channel width less than 10 metres for most of the year generally have flows that are too small to support navigable recreation by motorised craft.
Structures located within the beds of rivers and streams may alter flow characteristics, water levels or sediment transport patterns, and cause or contribute to erosion and/or deposition resulting in bed destabilisation. Structures in the beds or on the shores of lakes that interfere with either littoral currents or offshore currents, or reflect or refract wave energy, may also cause instability.
Structures may obstruct fish passage up and down rivers. Fish passage is important particularly for species that migrate up and down rivers as part of their life cycle. By blocking river channels, structures can prevent fish access to spawning grounds and to areas that have been used as traditional or recreational fisheries.
Tangata whenua have a special relationship with river and lake beds. For example, Waikato Tainui have a special relationship with the Waikato River and its tributaries as do Tuwharetoa with Lake Taupo, its tributaries and the Waikato River to the confluence of the Waipapa Stream. Tangata whenua are particularly concerned where disturbances affect the health of, or access to, traditional food. Tangata whenua are also concerned about the effects of structures and activities that disturb the beds of lakes and rivers, water quality and subsequent effects on traditional fisheries, other food resources and sites which are of spiritual, cultural and historical significance to tangata whenua. Also refer to Chapter 3.1 of this Plan for a discussion of tangata whenua concerns in regard to the management of water bodies.
Relationship to Other Chapters of the Plan
Chapter 3.6 addresses issues concerning the damming and diverting of water. Under s15 of the RMA the damming and diverting of water requires a resource consent unless there is a rule in a regional plan saying otherwise. The damming or diversion of water often involves the building of a structure in, on, under or over the beds of rivers that requires a resource consent under s13 of the RMA. In order to assist resource users, matters pertaining to the building of damming structures have been included in Chapter 3.6 so they are addressed in one place in the Plan.
Chapters 5.1 and 5.2 have specific rules concerning vegetation clearance, soil disturbance and discharges to land in areas adjacent to the beds of rivers and lakes. Any person building a structure in, on, under or over the bed of a river or lake that involves vegetation clearance, soil disturbance or a discharge to land in these areas should refer to the rules in Chapters 5.1 and 5.2.