Drain maintenance rule – Key issues & proposed amendments
Definitions • artificial farm drainage canal • drain • highly modified river or stream Concerns • complex, lack clarity, please map • water races, stormwater network, channels that flow only during rainfall?
Proposed amendments • New method: Map drains and highly modified water courses • Rationalise and reword definitions
Artificial farm drainage canal – delete Farm Drain An open watercourse, designed and constructed for the purpose of land drainage of surface or subsurface water from farmland. (Note - Most watercourses considered to be farm drains are actually natural watercourses that have been highly modified, often over many decades, and include channels dug to drain natural wetlands .)
Highly modified river or stream : For the purposes of Rule R121 only, means a river or stream that has been modified and channelled for the purpose of land drainage of surface or sub-surface water and has the following characteristics: • it has been channelled into a single flow, and • the channel is predominantly straight, with no ‘natural curves’, and • the channel is mechanically formed with straight or steeply angled banks, and
• it exhibits these characteristics for its entire length through the property in which the activity is being carried out and downstream to the next confluence. Note: Water races, the stormwater network, and artificial channels that only convey water during rainfall events are not highly modified rivers or streams.
Do the amended definitions make it easier to interpret which watercourses are covered by Rule R121?
Methods • Method M14 drain maintenance education programme Concerns • highlight collaboration with industry and landowners
Proposed amendments • Highlight importance of working with landowners & industry • I nformation to increase understanding of ‘drains’ as natural waterways and their ecological values • Support land management practices to reduce inputs of sediment and nutrients reducing need for ‘drain’ maintenance
R121(e) Sediment management R121(e) excludes sediment condition • impossible to meet • step-wise improvement • amend R121(k) to require sediment trapping + Method M14 to support practice change Discuss under clause (k)
R121(f) Changes in grade or x-section • Provide for fish refuge bays & livestock drinking bays Proposed amendments • Add ‘for purpose of constructing a fish refuge bay’ (link to clause (j))
R121(g) Weed bucket Concerns • Bucket specification too detailed Proposed amendments • Delete clause (g)
R121(h) Return of fish Concerns • clause is impractical - amend to take ‘all reasonable steps’ to return fish • require kakahi to be returned too Proposed amendments • maintain clause, minor rewording • add kakahi
R121 (i) sediment spread • Minor amendments for clarification
R121(j) Fish refuge Concerns • Clause is impracticable and inefficient Proposed amendments • Clarify intent to provide fish refuge • Provide options: (i) If waterway is wide enough, clear only one side or (ii) Leave vegetated refuge areas at intervals or (iii) Construct fish refuge bays at intervals
Are amendments to provide options supported? Are the following metrics about right: - a fish refuge area every 200m length of watercourse - a 10m long vegetated buffer - a 1m 2 fish refuge bay
R121(k) Sediment trapping Concerns • Working downstream is impractical Amendments • Replace with requirement for a sediment trap (a vegetation buffer or an installation) Are these amendments supported ?
Biosecurity (change to note) • Add a note to highlight need to comply with the Biosecurity Act
R121(new): Notification • Request notification to understand practice Is this addition supported ?
Drain Any artificial watercourse, open or piped watercourse, designed and constructed for the purpose of land drainage of surface or subsurface water and, for the purpose of Rule R121 only, excluding any ‘device’ included within the definition of stormwater network . Channels designed and constructed to convey water only during rainfall events and which do not convey or retain water at other times are excluded from this definition. Only for the purpose of Rule R121 (drain clearance) a drain also includes a highly modified watercourse or river and is channelled to such an extent that it has the characteristics of a farm drainage canal.
Note: For the avoidance of doubt, this definition does not include water races or artificial channels or swales that only convey water during rainfall events. Many watercourses that are considered to be drains are actually natural watercourses that have been highly modified, often over many decades, and include channels dug to drain natural wetlands.
For the purposes of Rule R121 only, means a river or stream that has been modified and channelled for the purpose of land drainage of surface or sub-surface water and has the following characteristics: to the extent that it has the characteristics of (in form or function) an artificial farm drainage canal . For the purposes of this definition, the characteristics of a farm drainage canal are considered to include that;
• it has been channelled into a single flow, and • the channel has been straightened is straight, with no ‘natural curves’ , and • the channel is mechanically formed with straight or steeply angled banks, and • it is maintained to keep the water table at least 0.3m below the root zone of the surrounding pasture, and • that it exhibits these characteristics for at least its entire length through the property in which the activity is being carried out watercourse is being assessed.
Note: Artificial channels that only convey water during rainfall events, water races and the stormwater network are not Highly modified rivers or streams
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